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Estimating Residual Fatigue Life of Bridges - Research Library

1. CQ v oc cles per Hours i Effective Stress Range 1 58 Printout from RFLO Program FIGURE 5 2 48 fatigue damage factor versus the stress range The damage factor is also the last column of the printout and is defined as Yi ST 5 4 This term is the function summed in Eq 5 1 the effective stress range calculation The larger values of this damage factor indicate the levels of stress range producing significant fatigue damage The two plots histogram and fatigue damage can be used to determine the significance of the measured stress ranges relative to the fatigue calculations Figures 9 3 and 5 4 show the stress range histograms for all intervals and each relevant individual interval Figure 5 5 shows the stress cycles in each interval Figure 5 6 shows the fatigue damage for each interval Most of the fatigue damage occurs at a stress range of 3 ksi Intervals 1 3 and 4 show significantly lower number of stress cycles 5 3 Calculating Fatigue Life It is recommended that a minimum of seven days of data be used in assessing a bridge This one week period should prevent a biases in the analysis due to daily truck tra
2. MM PROCEDURE GETC_COM VAR CH CHAR VAR AVAIL BOOLEAN REGS gt REGISTERS DONE BOOLEAN BEGIN IF COM READY THEN BEGIN REGS AX 0200 REGS 0 0000 INTROS 14 REGS CH CHRCLOCREGS AX AND 7F AVAIL TRUE END ELSE AVAIL FALSE IF AVAIL IF FULL DUPLEX THEN PUTC END EE PROCEDURE WRS COM MESS MESSAGE VAR 1 INTEGER CH CHAR BEGIN 1 TO ORD MESS 01 DO COM CMESSI1 COM CH CHAR_AVAIL YC200 ee x ie ieee ii s n PROCEDURE INIT_CAMPBELL VAR CH CH2 CHAR DONE BOOLEAN COM PAR CBAUD PARITY NSTOP NDATA CHR 13 CHAR AVAIL FALSE DONE FALSE WHILE NOT DONE DO BEGIN COMCCH 1 GETC_COMC CH2 CHAR IF CHAR AVAIL THEN BEGIN WRITECCH2 cL DONE TRUE END SE 100 PROCEDURE GO REMOTE VAR CH CHAR BEGIN INIT CAMPB WRS_COM 2 CH CHR PUTC_COMCC GETC COM C DELAY 200 PUTC COM CHAR AVAIL PROCEDURE OPEN COM BEGIN ASSIGNCSERIAL PORT COM REWRITECSERIAL PORT END PROCEDURE CLOSE BEGIN CLOSECSERIAL PORT END PROCEDURE SEND MODE 1 B
3. 3 2 22 Campbell 21X Box CHS 3 2 2 25 Battery Boxes o ly x39 dE 2 ee OUS RD e 4 2 2 3 Data General Computer and 4 2 2 4 Transducers Strain Gage Completion Boxes and Case 4 2 2 5 C Clamps and Tool 11 2 2 6 Cables and Connectors 11 2 2 7 Transducer Calibration Specimen 11 CHAPTER THREE TEST 13 idk Test Plany g x ZX uox lao ORE RA WA Q GA de A Ge hasa 13 3 2 Transducer Calibration 16 Power IY au s d he Se S 8 ad S ab BS 18 3 14 JBesICCanliS x e uae eade D G 19 3 5 Field Equipment Check List 19 3 6 Equipment Setup cse uode 20 CHAPTER 4 TEST 23 4 1 Program 23 4 2 Channel 25 4 3 Data Acquisition 5 25 odo oom e t e o 31 4 3 1 F1 Check Channels 4 54 9x 22 31 4 3 2 F2 Take Single Reading x x 34 4 3 3 Take Zero Reading 34 4 3 4 F4
4. e a Lr P Q a F zo o soc 000 oz lt gt u gt e 1c e gt u d gt gt Q Q ae w O lt lt 2 Aq o Uw JO ona 1 edo 2 ce LL Ode o gt A202 O r zog ROUND CTEMP REAL 9 updated E 79 0 79 0 5 be saved ITY MESS HOUR MESS nel P P e fo 2 gt a t eX m P C 3 o ng lt a zo c Oo O C c 1 a oo o o we gt 2 lO o gt gt gt o 2 n o gt 9 gt gt gt 2 Seo e dou lt lt gt lt o lt el x x gt OF cz qc Oc co Z l lt Ow u gt ul o 20 gt gt 2 gt Z gt u gt l e gt gt Oh oe gt gt gt z 0 Q0u rxul 0 O0O0u O uo Ix o oodo
5. lo gt gt d lt K LJ O lt K LU O C GOnMOSHNKOSZNAS WAIT 2 TOGGLE_RECORD 1 CLSCACTIVITY MESS ROW O ACTIVITY MESS ROW 79 0 AR ACQ SCREEN i END END FG 3 F 10 BEGIN save rainftow data WRCOLCACTIVITY MESS ROW 0 3 Setting Rainflow capture flag off INIT CAMPBELL WAITC5 TOGGLE RECORD 1 XX ACO SCREEN CLSCACTIVITY MESS ROW O0 ACTIVITY MESS ROW 79 0 WRCOLCACTIVITY MESS ROW 0 3 Channe description must read Press any key GETCCKEY CLSCACTIVITY MESS ROW O ACTIVITY MESS 79 0 LOAD FILECACTIVITY MESS ROW 0 5 MESS ROW O ACTIVITY MESS ROWwW 79 0 SAVE RAINFLOW DATA CURSORCACTIVITY MESS ROW O END E F10 1 ESC DONE TRUE END case END while PAGE OLD PAGE SEL PAGE CLSCO 0 24 79 0 END 6 PROCEDURE DESCRIBE VAR DONE BOOLEAN DN BOOLEAN MESS MESSAGE CHANNEL INTEGER BEGIN CURR PAGE 1 SEL PAGE f IF NOT SCREEN SET THEN BEGIN CLS 0 0 24 79 0 SHOW TABLE SHOW VALUES END WHILE NOT DONE 00 BEGIN ROW CHANNEL _INFOLCURRENT_CHANNEL ROW CASE CURRENT_FIELD OF t BEGIN COL CHANNEL INFOL CURRENT CHANNELI TRANSDUCER COL GET_TRANSDUCERCCHANNEL_INF
6. t parameter 2 initiat location of input WRS COM A advance WRS COM A f parameter 3 on line cont processing WRS COM ACMEANS _BINS t parameter 4 of means beans WRS COM A advance WRS TO ACAMPLITUDE BINS parameter 5 of amplitude beans wRS COMC A advance wWRS_COM l _ ACLOW_LIMIT parameter 6 low limit of input data mv IF LON LIMIT lt 0 THEN WRS COM C wRS COMC A advance WRS TO A CHIGH parameter 7 high limit of input data mv WRS COM A t advance PEAK VALLEY DISTANCE WRS TO ACPEAK 95 0 CHANNEL 1 SR MIN CHANNEL INFOLCHANNEL SR MAX VALLEY DISTANCE 2 2 0 parameter 8 minimum distance between peak and valley a p p t t WRS COM dvance WRS COM 11A t arameter 9 open form counts recorded WRS COM C OA f parameter 10 send output to final storage INITIAL LOC INITIAL LOC 1 if defined 3 end instruction t label subroutine instruction parameter 1 subroutine 2 t do command instruction f parameter 1 set output flag sample and output data in input storage J CHANNELS advance 1 98 parameter 1 8 of transducers WRS_COMC 2A location of initial input storage location WRS COM 95A end instruction j WRS COMC X 0
7. 01 GETNAM CFNAMELO lt gt CHRCOOD file specified THEN BEGIN I 1 3 WHILE FNAME 1 lt gt DO ft 5 1I 1 FNAMEL 11 2 F FNAMEL1I 31 L 1 ROS GNCOATASEEEESE NAME f RESETCDATA_FILE CLOSECDATA_FILE 14 FOUND IOresult 0 IF FOUND THEN duplicate file exists BEGIN WRCOLCACTIVITY_MESS_ROW FILE_COL 25 4 File exists Overwrite Y DN FALSE L6 WHILE NOT DN DO BEGIN GETCCKEY Eu IF CHRCKEYO IN Y y N n THEN DN TRUE D IF CHRCKEYO IN Y y THEN overwite file J BEGIN RETRIEVE DONE TRUE END END E then ELSE BEGIN RETRIEVE DONE TRUE END ENO ELSE DONE TRUE END END I rur C ca PROCEDURE ACQUISITION VAR DELAY INTEGER i 5 ARRAY 4 K INTEGER OLD_PAGE BYTE DONE AVAIL BOOLEAN CH CHAR RESPONSE 1 MESSAGE COUNTER INTEGER TEMP_REAL REAL N_CHAN INTEGER PCHAN PLOT CHANNELS PROCEDURE GET _PCHANCVAR INTEGER VAR PCHAN PLOT_CHANNELS VAR ROW COL INTEGER DONE BOOLEAN FOUND BOOLEAN TEMP REAL REAL CHAN INTEGER BEGIN ROW SPEM MESS ROW COL CLSCACT Ivitv MESS ROW 0 ACTIVITY MESS ROW 79 0 WRCOLCACTIVITY MESS ROW 0 3 Enter channels to be plotted 3 DONE z
8. 9 Data General Computer e hn 10 Transducers Completion Boxes and Case 10 Transducer calibration specimen nien e 12 Bridge Test Data Sheet 14 Transducer Calibration Program m 17 Equipment edu 2i Mari NIBH Z 2 x Red me MM SA QE us 24 Example Test Data Sheet P War 26 Channel Description Input Screen ois urge 27 Example Channel Description Data 2210 Data Acquisition Example Test P osx xd RFLO Input 45 Printout from RFLO Program oh m 4 4 47 Stress Range Histogram Intervals xp 30 Stress Range Histogram Each Interval Cycles Per Interval ee he adi a x S 90 Fatigue Damage Spreadsheet Output 51 Influence of Growth Value on Error ADT 2 2 53 Influence of Growth Value on Fatigue Life ax 109 ADT Estimate 64 Fatigue Life Estimate Years ln 94 Influence of Cycles Day From Field
9. OFFSET e n FOC JI MULTIPL ed Press an 102 UX RESPONSE OMCCR C READLN ae UJ LLJ Updating pointers MESS ROW 79 0 SS ROW 4 3 Capture stopped SS MESS ROW 79 0 gt gt m Eo o on e ao gt oz IE o gt jew gt gt we A gt gt gt gt gt lt 2 lt Hie MESS 0 amp jn E u gt z G O gt lt I now o OG x am 0Q c jo Or 223GC Ouo 2 zuoz OOozT oO oo xx amp 0 u 6 i xx oo z lt I lt m 2 lt 2 I c O e z e lt an I X z 62 2 ri GO w 5 d gt 2 2 oz Z 20909 gt 624 How Ox OO wa an je a jue O gt gt Zu uuoo s zma os 9ra Oat V0 ul 2 uic ua MN u wr L E tw e 4 4 23 c E c e or he a eo 2 or c at
10. N_CHAN WHILE NOT DONE DO BEGIN TEMP REAL 9999 9 CURSORCROW COL GETNUMCTEMP REAL 1 0 IF TEMP REAL 0 0 THEN BEGIN CHAN ROUNDCTEMP_REAL FOUND FALSE FOR 1 TO CR21X_CHANNELS DO BEGIN CHAN ACTIVE_CHANNELS I THEN FOUND TRUE END FOR 1 CHAN DO BEGIN CHAN PCHANEI THEN FOUND FALSE ENO IF FOUND THEN BEGIN 86 END END BEGIN DONE fALS CLS 0 0 24 7 OLD_PAGE SoC 6 SEL PAGE CHAN CHAN CHAN WRCOLCROW COL d51 WRCOL CROW COL 1 23 COL COL 2 i END ELSE WRCOLCROW COL 3 221 2 END ELSE DONE TRUE E 3 9 0 CURR PAGE 2 00 MESS ROW O ACTIVITY MESS ROW 79 0 ACTIVITY MESS ROW 3 Waiting for command EY TIVITY_MESS_ROW 0 ACTIV ITY_MESS_ROW 79 0 PRESSED OF BEGIN check WRCOLCACTIVITY MESS ROW 4 3 Checking channels ur E WRCOLCACTIVITY_MESS_ ROW 60 3 scanner TOGGLE_RECORD 2 WRCOLCACTIVITY MESS ROW 60 3 stop scanner2 TOGGLE_RECORD 2 ACQ_SCREEN WRCOLCACTIVITY MESS ROW 4 3 Checking channels WRCOLC CACTIVITY MESS ROW 60 3 get pointers POINTERS COUNTER NSCAN FOR I TO CR21X _CHANNELS DO BEGIN ACTIVE 1 CHANNEL INFOLJJI CURRENT 0 0 i CHANNEL INFOL J HI 499999 9 CHANNEL_INFO J LO
11. SIGN 001 34 K WLEN INTEGER TEMP1 TEMP2 FACTOR INTEGER i ALPHA MESSAGE BEGIN IF IVLU O THEN BEGIN IVLU VLU SIGN 1 END IF VLU 0 THEN BEGIN ALPHAT 03 CHR 1 11 0 A 2 ALPHA END E SE BEGIN TEMP 1 VLU WLEN gt 0 WHILE NOT TEMPI lt 1 DO BEGIN TEMP TEMP DIV 10 WLEN 1 END EMP VLU 2 IVLU OR J 1 TO WLEN DO 555 j FACTOR 1 WHILE K lt WLEN DO BEGIN FACTOR FACTOR 10 K K 1 END TEMP1 2 DIV FACTOR ALPHA J CHRCTEMP1 48 cid 2 TEMP2 FACTOR 1 ALPHALO CHR WLEN IF SIGN 1 THEN BEGIN FOR I DOWNTO 1 DO ALPHAtI 1 ALPHA 11 ALPHA 0 CHRCWLEN 1 END ALPHA END END 4 FUNCTION FCASCII MESSAGE REAL VAR J K L M INTEGER INDEX INTEGER SIGN REAL WSTRG STRING 5 89 ww L J OR ASCITUJ J THEN SIGN 1 0 WHILE ASCII J1 lt gt DO BEGIN K 1 ASCIIIJ TEMP ORD WSTRGILI 48 FOR M L 1 DO TEMP TEMP X 10 WHOLE WHOLE TEMP RGIL 48 K 1 DO TEMP TEMP 10 TEMP is 7 i Hoe HO
12. FALSE parameter change needs to be programmed N IF CHANNEL DETAIL N E ELSE BEGIN WRCOL ROW COL 3 WRCOLCROW COL 4 3 TO IF 010 DETAIL lt gt CHANNEL DETAIL BEGIN CHANNEL SR MAX 1 0 1 HARNESS MIN 1 0 i IF CCCHANNEL DETAIL gt 0 ANO CHANNEL DETAIL lt 7 THEN BEGIN CHANNEL SR MAX SRMAX CHANNEL DETAIL CHANNEL SR MIN SRMINOICHANNEL DETAIL WRCOL CROW COL 12 3 WRCOLCROW COL 12 3 F ACCHANNEL SR MAX 2 2 CROW COL 20 3 9 mun oT en eee ET HE 3 END TIMECROW COL INTEGER V I8 TEMP REAL REAL STR MESSAGE WIT BEG H REGS DO BEGIN AX 2COO MSDOSCREGS CURRENT HOUR HICCX CURRENT TIME MINUTE LOCCX a SENI TEN SEDE HI DX N WRCOL CROW COL 3 Current time is WiTH CURRENT TIME DO BEGIN STR ACHOUR O IF ORDOCSTRIO1 1 THEM BEGIN STRI2 STRI1 STR 1 0 STR 0 CHRC2 END WRCOL CROW COL 16 3 STR WRCOL CROW 18 3 STR TO ACMINUTE IF ORDCSTR O1 1 5 21 STRC1 STRI1 STRIO CHR 2 END i N 4 TEMP REAL 9999 0 WRCOL ROW COL 25 3 Enter new hour CURSORCROW COL 42 GE
13. tr Q o C mr Oo x O JTO O mg Z u lt O Zu lt Ou O x CLSCACTIVITY MESS MESS 79 0 END BEGIN DONE FALSE WRCOLCACTIVITY MESS ROW 0 3 Verifying channels i WAIT 2 GET NUMBER CHANNELS WAIT 2 IF CR21X CHANNELS 0 THEN BEGIN WRCOLCACTIVITY_MESS_ROW 0 3 No channels to read Press any key GETCCKEYO DONE TRUE END CLSCACTIVITY MESS MESS ROW 79 0 ACQ SCREEN WRCOL CACTIVITY MESS ROW 0 3 Verifying number of elapsed intervals IF NOT DONE THEN BEGIN GET CR21X TIME MINUTES 5 ELAPSED 1 24 60 CR21X_TIME HOUR 60 CR21X TIME MINUTEO 1440 START TIME HOUR x 60 START TIME MINUTE INTERVALS ELAPSED MINUTES DIV RAIN INTERVAL INTERVALS ELAPSED MAX INTERVALS THEN INTERVALS ELAPSED MAX INTERVALS IF INTERVALS ELAPSED 0 THEN BEGIN WRCOLCACTIVITY MESS ROW 0 3 No data to read Press any key i GETC CKEY DONE TRUE END END WHILE NOT DONE DO BEGIN IF CFNAMEL O lt gt CHR 0 THEN BEGIN FOR 1 TO ORDCFNAME 01 2 DO TEMP 1 FNAME 1 2 END NAMELO1 CHRCORD C FNAMEL O1 2 2 CLSCACTIVITY MESS ROW O ACTIVITY MESS ROW 79 0 WRCOLCACT VITY MESS ROW FILE COL 3 Save File CURSOR CACTIVITY MESS _ ROW FILE 12
14. 56 Influence of ADT Capacity on Fatigue Life SX xw 90 Changing Scan X CHAPTER ONE INTRODUCTION This manual describes the capabilities and operating procedures for an automated bridge testing system The system was developed for the Texas State Department of High ways and Public Transportation to provide a portable self contained and user friendly means for evaluating the residual fatigue life of steel girder bridges The bridge testing system has been designed so that it can be easily installed on a bridge in less than a day and can record data automatically for up to two weeks The system has been enclosed to protect the electronic components from the environment and the entire system can be clamped onto a bridge girder The main components of the system are a Campbell Scientific eight channel dat alogger and a Data General portable computer The Data General computer is used to program the Campbell to record strains measured using conventional strain gages or spe cial clamp on strain transducers The system is very flexible with respect to the types of data that can be collected The Campbell can be programmed to record data continuously while a truck of known weight crosses a bridge and this data can be used to check analysis results The Campbell can also be programmed to record and count stress cycles using the rainflow method for use in fatigue analysis Other types of special te
15. 0 COL 1 WRCOLCROW COL 14 2 CURSORCROW COL D WLEN WLEN 1 END ELSE JF 46 AND CWLEN gt 0 IF CFL gt WR COL ROW COL COL END WHILE NOT FDONE DO BEGIN GETCCCB NUMERICCCB THEN dae w END SE SPECIA THEN B E END WL gt 0 AND WLEN gt 0 WHILE J gt 0 DO P 1 CURSOR ROW COL END WDONE TRUE END ELSE DISP ERRC5 ooz ZO w mz m u gt m ND CB 8 MES COL COL 2 WRCOLCROW COL 14 79 CURSOR ROW COL WDONE FALSE WLEN 1 FDONE TRUE END ELSE DISP ERR C5 9 99 WHOLE WHOLE TRUNCCORD CENTRY 48 MUL MUL MUL x 10 0 J J 1 END FRAC 0 0 MUL 10 0 J 1 WHILE J lt WLEN FLEN DO BEGIN FRAC FRAC CTRUNCCORDCENTRY J 48 MUL MUL MUL x 10 0 J J 1 END NUMBER WHOLE FRAC LAST NUM NUMBER END END 4 FUNCTION F TO REAL WL FLEN INTEGER MESSAGE VAR SIGN l J K INTEGER TEMP 2 FACTOR REAL ALPHA ALPHA2 MESSAGE BEGIN SIGN 1 IF VLU lt 0 0 THEN BEGIN VLU VLU SIGN END TEMP 1 VLU WLEN 0 WHILE NO
16. flashing light 5 COM 3000A WRS COMCI TO ACINPUT LOCATION 5 COMC A WHS COMC 21A7 wWRS COMC 1A WRS COM TO AC NPUT_LOCATION WRS COM A WRS_ COM 30A WRS COMC OA WRS COMC I TO ACINPUT LOCATION 12 1 WRS COM A WRS COMC 21A WRS COM 1A WRS TO ACINPUT LOCATION 1 WRS COMC A WRS COM X3A UXX X Xx xk ENTER MODE 3 3 WRS COM B85A labe subroutine WRS 1A subroutine 1 7 range channel level 3 multiplier 3 L8 WRS COM 92A COM OA 5 COMCI TO WRS COMC A WRS COM 10A WRS COMC 7A wRS COM 110A INITIAL FOR CHA BEG t NE E END WHS COM 9 8 WRS_COM WRS COM 2 5 COM 864A WRS COM 10A WRS 70 wRS COMCI TO WRS COMC A gt gt 5 5 r A if time output instruction sets time interval for output of data arameter 1 tart at time 0 RAIN I TERVAL parameter 2 rainfiow time interval advance parameter 3 set output flag for end of i time interval output time tagging instruction parameter 1 day hour minute format 2 1 1 TO 8 DO D CCHANNEL IN WRS COM 81A i rainflow intermediate processing inst 5 COM 1A parameter 1 of transducers WRS TO
17. the total number of cycles recorded gt n Note that mean stress is not included in equation 5 1 Fatigue research on welded structural steel details indicate that mean stress is not a significant variable The number of cycles at the two mean stress levels should be added to obtain for each Spri The effective stress range represents the stress range which produces the same fatigue damage as the variable stress cycles measured on the bridge The estimated fatigue life in cycles can be calculated using Eq 5 2 Nije SR 5 2 The constant A in equation 5 2 is obtained from the fatigue life equation of the detail on the bridge where the stresses were measured The value of A can be obtained from the 43 44 AASHTO fatigue design stress ranges for redundant load path members at 2 million cycles in Table 10 3 1A using the equation below A 2x 106 x 5 3 where Srp is the stress range in Table 10 31A for the detail under consideration In order to relate the cyclic life from equation 5 2 into the structure life in years an estimate of the number of cycles per year is required The number of cycles in a year can be estimated by annualizing the cycles gathered in the field collection period and adjusting this estimate for past and future traffic volume differences Methods of adjusting the number of cycles using traffic surveys and estimated traffic volumes are presented later The measured stresses may often b
18. 16 i KEY gt REGS AX AND SOOFF KEY PRESSED REGS AX ANO DIV 256 END dl ed wed i us PROCEDURE WRCOLCROW COL COLOR INTEGER MESS MESSAGE VAR l J K INTEGER REGS REGISTERS COL J ORDCMESS 0 FOR I 1 TO J OO BEGIN CURSORCROW K REGS DO BEGIN AX gt 9 256 ORD MESSEI 1 8x gt CURR PAGE 256 COLOR CX gt 0001 INTRCS1O REGSO K z K 1 END ENO 19 PROCEDURE CURSOR VAR ROW COL BYTE VAR REGS REGISTERS BEGIN REGS AX 0300 REGS BX CURR PAGE 256 O INTR CSIO REGS ROW REGS DX AND SFFO00 DIV 256 COL REGS DX AND SOOFF PROCEDURE VDO STATCVAR MODE PAGE BYTE 1 VAR REGS REGISTERS BEGIN REGS AX OFOO INTRCSIO REGS MODE LOCREGS AX WIDTH HICREGS AX PAGE gt HICREGS BX END PROCEDURE VDO_MODECMODE BYTE VAR REGS REGISTERS I BEGIN REGS AX 0000 MODE INTR 10 REGS END FUNCTION NUMERICCCH BYTE BOOLEAN BEGIN NUMERIC FALSE IF CCH gt 48 AND CH lt 579 THEN NUMERIC TRUE END FUNCTION SPECIAL CB BYTE BOOLEAN BEGIN SPECIAL FALSE IF CB 13 OR CB 44 OR KEY PRESSED UP ARROW OR KEY PRESSED DN ARROW OR KEY PRESSED LT ARROW
19. 3 CURSORCROW COL FDONE FALSE i FLEN FLEN 1 1 EDONE TRUE END ELSE DI SP ERRC1 END END IF FLEN 0 THEN BEGIN NEW PF TRUE PF FOUND FALSE 3 NAME OJ CHR FLEN ELEN 3 01 a 11 DEFAULT DRIVE FNAMET 2 Ga NEN FOR t 3 01 DO FNAMEE END END 6 PROCEDURE GETNUMCVAR NUMBER REAL WL FL INTEGER VAR ENTRY ARRAY 1 101 OF CHAR Io J INTEGER WHOLE FRAC MUL REAL WLEN FLEN INTEGER DONE WDONE FDONE BOOLEAN CB BYTE CH CHAR ROW COL BYTE BEGIN CURSORCROW COL FOR I 1 TO 10 DO ENTRY L11 WLEN IF WL gt 0 THEN WDONE FALSE ELSE WDONE TRUE DONE FALSE WHILE NOT DONE DO BEGIN FLEN O IF FL gt 0 THEN FDONE FALSE ELSE FDONE TRUE WHILE NOT WDONE DO BEGIN GETC CB IF NUMERICCCB THEN BEGIN WLEN WLEN 1 ENTRYIWLEN CHR CB CROW COL 14 ENTRYIWLEN 1 COL COL 1 CURSORCROW COL IF WLEN L THEN FDONE THEN BEGIN WDONE TRUE DONE TRUE END ELSE BEGIN WDONE TRUE WRCOLCROW COL 14 COL COL 1 CURSORCROW COL END END ELSE IF SPECIALCCB THEN BEG IN WDONE TRUE G9 D
20. 1980 20 000 This measured traffic data can be used to estimate the traffic for the life of the structure using simple compound traffic growth model shown below ADT 1 Ry 5 5 where ADT ADT after j years R rate of growth per year In order to use this formula the value of R must be estimated from the measured data A SuperCalc spreadsheet was used to determine the best fit R value This spreadsheet was also used for some of the ratio calculations The template file is named fatigue cal and is on the diskette provided Figure 5 8 shows the absolute error of the predicted ADT versus the measured values for R from 0 04 to 0 063 The lowest error best fit R value is R 0 051 The estimated fatigue life is sensitive to value of R Figure 5 9 shows how the predicted fatigue life changes with R with all other parameters remaining constant Figure 5 10 shows the 53 Influence of Growth Value on Error in ADT Capacity 50 000 Cycles Day Field Test 2565 100 ene Absolute Error ADT 20 0 4 0 4 5 5 0 5 5 6 0 6 5 Estimated Growth Value R Figure 5 8 Influence of Growth Value on Fatique Life Capacity 50 000 Cycles Day Field Test 2565 L A n _o gt S amp 1qA lt Q nn x L Fatigue Life Estimate Years 69 Hu Gr c c ccm sa 04 045 05 055 06 065 Estimated Growth Value R Figure 5
21. case END END END white not done END 85 PROCEDURE DIRECT VAR DONE BOOLEAN BEGIN CLSCO 0 24 79 0 DONE FALSE WHILE NOT DONE DO BEGIN _ WHILE KEYPRESSEO DO BEGIN GETC COMCCH CHAR AVAIL WHILE CHAR AVAIL DO BEGIN IF ORD CH lt gt 17 THEN WRITECCH GETC_COM CH CHAR AVAIL END END GETC KEY SOT CASE KEY PRESSED SET PAR 4 INIT CAMPBELL MOTE DONE TRUE 98 T T r 0 G gt e 2 END END case END CLSCO 0 24 79 0 i gt x r o ATTN zm m o S STATE DEPARTMENT OF HIGHWAYS PUBLIC TRANSPORTATION t w Level Programming i1 anne Description i WRC ou rm n n Acquisition Menu t to DOS 9 lt af j 00 48 4 d PP or lt lt OO we lt lt Oe ftn 4 GRAMMED THEN ACQUISITION 1 SORCCUR ROW CUR COL 5 3 TO DOS Y or N 1 8 2 rm n 2 0 40 c D 0 momm f oma 4 mz m x 21 78 11 0 HAE 4 E i 23 4 ROW
22. ROW 1 FOR ROWS 1 TO 7 DO BEGIN WRCOL ROW COL 3 TABLE_M IDDLE WRCOL ROW 1 COL 3 TABLE_LINE ROW ROW 2 END WRCOL ROW COL 3 TABLE MIDDLE WRCOL CROW 1 0 3 TABLE BOTTOM WRCOL CTABLE START ROW 1 TABLE START COLUMN 1 3 Channel WRCOLCTABLE START ROW 2 ARRESE TANT CEUM 3 WRCOLCTABLE START ROW 1 COLUMN 11 3 Channel WRCOLCTABLE START ROW 2 TABLE START COLUMN 11 3 Type 1 WRCOL CTABLE START ROW 1 TABLE_START_COLUMN 26 3 Calibration i MR Ut TAPRE RON TABLE START COLUMN 27 3 S MV V 1 WRCOL TABLE_START_ROW 1 TABLE START COLUMN 41 3 Fatige WRCOL CTABLE START ROW 2 TABLE START COLUMN 41 3 Detarirl WRCOL CTABLE START ROW 1 TABLE START COLUMN 53 3 Sr i wWRCOL CTABLE START ROW 2 TABLE START COLUMN 53 3 WRCOL CTABLE START ROW 1 START COLUMN 60 3 Sr WRCOL CTABLE START ROW 2 TABLE START COLUMN 60 3 min H O gag Se TAB ER TABLE_START_COLUMN 4 3 1 WRCOL TABLE_START_ROW 6 TABLE_START_COLUMN 4 3 727 WRCOL TABLE_START_ROW 8 START COLUMN 4 3 3 WI O ADLE STAR E CLUAN A S enia WRCOL CTABLE START ROW 12 TABLE START 4 3 5 HOO IA ES IA O WRCOL TABLE_START_ROW 16 TABLE_START_COLUMN 4 3 7 WRCOL TABLE_START_ROW 18 TABLE_START_COLUMN 4 3 8
23. 19 The operating times given above are based on the performance of relatively new batteries operating at moderate temperature approx 70 F Consideration should be given to the drop in performance of the batteries with age and at lower temperature Battery performance will drop considerably if the test is conducted at colder temperatures Extreme care should be taken to insure that sufficient battery power is available for the full length of the test since all of the data will be lost if the battery voltage drops below the threshold needed to operate the Campbell power supply is also required for the Data General during test set up and data retrieval The Data General has an internal battery which when fully charged can operate the computer for a maximum of two hours Additional power can be provided by a portable generator or by the 12V batteries special adaptor has been provided which converts the 12V battery supply to the 7 5V used by the DG The cable on this adapter is approximately 15 ft long and has a 2 pin connector for connecting to the battery It should be noted that running the Data General off of the 12V batteries will reduce the length of time which the Campbell can run Care should also be taken when running the Data General off of a portable generator since sudden power surges can damage the computer in line voltage meter is useful in monitoring the output of the generator 3 4 Desiccants Inside the Campbell are
24. 2 PARITY 0 END CASE PARITY OF 0 WRCOL 6 49 3 None 1 WRCOL 6 49 3 Odd 2 WRCOL 6 49 3 Even END END 1 F5 BEGIN CASE NSTOP OF 1 NSTOP 2 2 2 NSTOP 1 END f case CASE NSTOP OF 1 WRCOL 7 52 3 1 2 WRCOL 7 52 3 2 END f case 1 END F5 1 F7 BEGIN CASE NDATA OF 7 NDATA 8 8 NDATA 7 END case CASE NDATA OF 7 WRCOLC8 52 3 7 8 WRCOL 8 52 3 8 END f case END ELSE BEGIN END END case key of 1 END COM PARCBAUD PARITY NSTOP NDATA CURR PAGE SEL PAGE END PROCEDURE COM STAT CVAR LINE MODEM BYTE VAR REGS REGISTERS BEGIN REGS AX 0300 TZ REGS DX 0000 INTRCSTA REGSD LINE HICREGS AX MODEM LOCREGS AX END o m pL ML ee PROCEDURE PUTC_COM CH CHAR VAR REGS REGISTERS DONE BOOLEAN i BEGIN REGS 0100 REGS AX REGS AX REGS DX 0000 INTR 14 REGS END ee
25. 4 5 s excitation z excitation location BEGIN IF DEFINEDCCHANNEL THEN BEGIN CHANNELS CHANNELS 1 ACTIVE z CHANNEL 5 COM 6A full i Le b rs j WRS COM 1A param 8 repetitions for 1 WRS COM I TO A CHANNEL NFOLCHANNEL 1 RANGED s f param WRS COM A WRS 6 ACCHANNEL2 2 ft param 3 input channel 8 j WRS_COMC A WRS COMCI TO ACCHANNEL INFOLCHANNELJ EX CHANNEL2 param 8 5 COM A WRS Le Lona f param 5 COM A WRS TO ACINPUT_ LOCATION f param 6 input storage WRS_COM A WRS_COM F_TO_ ACCHANNEL_INFOLCHANNEL MULTIPLIER 4 42 f param WRS COM A WRS COM CF TO ACCHANNEL INFO CHANNEL OFFSET 4 4 IF CHANNEL 3 lt 0 THEN WRS__ C WRS COM A INPUT LOCATION INPUT LOCATION END END WRS COM 91 A if flag set control instruction used to start and stop data processing subroutines 5 COMC 11A t parameter 1 do if flag is set WRS COMC 1A t parameter 2 call subroutine 1 WRS COMC 91A if flag set control instruction used to t start and stop data processing subroutines 1 WRS COM 12A parameter 1 do if flag 2 is set wRS COM 2A t parameter 2 cali subroutine 2 WRS COM 30A
26. COL z OL 20 WRCOL MESSAGE ROW 0 3 SR MIN M IF CHANNEL I NFOL CHANNEL 1 SR MI THEN WRCOL CROW COL HILITE F T OW CHANNEL_INFOC CHANNEL uan N INFOLCHANNELJ SR MIN 2 2 6L ELSE WRCOLCROW COL 2 HILITE CURSORCROW COL DONE FALSE 99 GE TNUMCTEMPREAL IF TEMPREAL 0 THEN d BEGIN CHANNEL 1 5 IF CCCHANNEL CHANNEL INFO CHANNEL THEN BEG 99 2 2 2 0 s MIN L J DE AN DE vas T RE TAIL 7 TAIL 0 P gt F E E N 1 DETAIL CHANNEL_INFOICHANNEL SR_MIN PDATE_SCREEN_SR END PROGRAMME END WRCOLCROW COL 3 IF na 5 0 0 FALSE parameter change needs to be programmed THEN WRCOLCROW COL 3 F_ ELSE WRCOLCROW COL 2 3 9 PROCEDURE S CALIBCVAR S CALIB REAL ROW COL INTEGER VAR TEMPREAL REAL DONE BOOLEAN BEGIN WRCOL MESSAGE_ROW 0 3 S_CAL B_MESSAGE S_CALIB 9999 0 THEN WRCOL CROW COL HILITE F_TO_ACS_CALIB 2 2 ELSE WRCOLCROW COL 2 HILITE CURSOR CROW COL DONE FALSE TEMPREAL 9 L E f parameter change needs to be programmed 7 ROW COL 3 PROCEDURE GET MVPERV CALIBCVAR MVPERV CALIB REAL ROW COL INTEGER VAR TEMPREAL REAL DONE BOOLEAN 8EGIN WRCOL MESSAGE_ROW 0 3 MVPE
27. lt lt c lt lt lt lt O t lt lt lt I lt lt O e 9 UJ O O lt we O lt O 9 1 JANAN Maus IM mq O00000 100 joOu ma OOOO0DOOoOr COOOZzooo oOoozzca co ZO Ic Og oOocdctuodcdcacaoozcaoogctmatoo zu aga 3r ec z zo zxzo zzz zzou N u X_CHANNELS DO SS_ROW 60 3 ent r 1 ROW O0 ACTIVITY MESS T iTY_ Tivi Y_MESS_ROW 0 e t t c eA dw Q oo Ed D 63 e Y e m O To r 0 zz z zz OO o 5 an d an oo ov an uJ gt 2 25 gt gt gt gt gt F3 x F 4 F 5 GET POINTERS COUNTER NSCAN FOR 1 CR21X _CHANNELS DO BEGIN J ACTIVE _CHANNELS 11 CHANNEL INFOL J1 ZERO 0 0 END ACQ SCREEN WRCOL CACT VITY MESS ROW 4 3 Taking zero readings WRCOLCACTIVITY MESS ROW 60 3 averaging scan FOR K 1 TO NSCAN DO BEGIN WRCOLCACTIVITY MESS 76 3 9 3 WRCOLCACTIVITY MESS 76 3 1 TO ACCOUNTER COUNTER COUNTER 1 DUMP 5 1 _ 5 FOR 1 TO CR21X CHANNELS DO BEGIN ACTIVE_CHANNELS pA CANNEL ZERO gt DATA POINTSIUL1 VAL CHANNEL I EN
28. the remaining life of the bridge may show the existing structure can remain in service The resulting savings may be considerable In addition an accurate fatigue life assessment method will allow the replacement of deficient bridges to be scheduled in an orderly and efficient manner based on the estimated remaining service life The determination of the residual fatigue life of an in service bridge requires an accurate means of estimating the stress history of the bridge The procedures used in design of new bridges do not lend themselves to accurate prediction of fatigue lives The design procedures do provide conservative designs by using simplified vehicle load distribution factors impact fractions and design load placements Measured live load stresses are normally much less than the calculated design stresses more accurate fatigue life prediction can be made using the live load stresses measured on the bridge during normal traffic conditions equipment and analysis procedures presented in this report are designed to allow the fatigue life of existing bridges to be determined based on measured stress The equipment uses state of the art fatigue life assessment techniques The equipment is designed to be used without extensive training of the users to be rugged and reliable The report is written in the form of a user s manual of the equipment developed in the study 111 SUMMARY The research effort produced a portable and
29. transducer output in MV V versus the stress in the calibration bar The transducer output will be equal to the transducer reading minus the original transducer reading at zero load The stress in the calibration bar will be equal to the load reading divided by the cross sectional area of 75 2 A best fit line should be determined for the data and any point on the line can be taken as the calibration data for the transducer It is recommended that the calibration test be run two or three times for each transducer and the results averaged The transducers should be recalibrated after every three or four tests or whenever a transducers has been subjected to stresses over approximately 10 ksi 3 3 Power Supply Power for running the Campbell during a test is provided by 12 volt marine batteries If fully charged one battery provides enough power to operate the Campbell for at least 18 days when all eight channels are being used If fewer channels are being used then the Campbell can operate longer If a longer test is desired then a second battery can be connected to the Campbell and the operating duration will be doubled Two battery connectors wired in parallel have been provided on the Campbell box for this purpose Batteries can also be switched out during a test fully charged battery can be connected to the second battery connector and the old battery can then be disconnected Two 12V batteries have been provided with the system
30. 08996 stress cycles per vehicle This ratio is extremely important in determining the estimated fatigue life Figure 5 12 shows how the fatigue life estimate changes as the average number of stress cycles per day is changed A low of 1 317 and a high of 3 575 were measured during the field test The result is a two fold difference in fatigue life A field test duration should be long enough to insure that daily variations in traffic do not cause the number stress cycles counted to be biased The last figure Fig 5 13 shows how the estimated fatigue life varies with the estimated ADT capacity In this example capacities above 75 000 do not significantly change the fatigue life since the majority of the fatigue damage occurs before the ADT reaches this capacity The estimated life for this example based on steady state number of fatigue cycles equal to the average measured in the field test for the life of the bridge is 88 years Using a best fit R of 0 051 and a ADT capacity of 50 000 yield a life of 77 years Using the same value of R and ADT capacity but increasing the number of stress cycles per day to the maximum in the field test yields a fatigue life of 62 years Therefore based on these estimates the Category E detail in the example bridge would be expected to have significant cracks after a life of 60 80 years or between the years 2013 and 2033 The bridge should be inspected and retrofitted prior to this date Further future fie
31. 2 2 ELSE WRCOLCROW COL 13 3 WRCOL CROW COL 7 3 S 1 IF CHANNEL I NFOLCHANNEL 1 MVPERV CALIB gt 9999 0 THEN WRCOL ROW COL 7 3 F ACCHANNEL INFOLCHANNELI1 MVPERV CAL B 2 2 ELSE WRCOL ROW COL 5 3 IF CHANNEL INFOLCHANNELI DETAIL 0 THEN BEG N WRCOL ROW COL 3 Undefined END ELSE BEGIN WRCOLCROW COL 3 pur nec cm WRCOL C ROW COL 12 5 ue IF CHANNEL INFOLCHANNEL1I SR MAX gt 0 0 THEN wRCOLCROW COL 12 3 F TO ACCHANNEL INFOLCHANNELJI SR 2 2 ELSE WRCOL CROW COL 12 3 WRCOL CROW 20 3 i IF CHANNEL INFO CHANNEL1 SR MIN gt 0 0 THEN wRCOLCROW COL 20 3 F ACCHANNEL INFOLCHANNELIJ SR MIN 2 2 ELSE WRCOL CROW COL 20 3 2 3 ROW ROW 2 ENO END 4 PROCEDURE SHOwW TABLE VAR CHANNEL ROWS ROW COL INTEGER CAT 5 41 BEGIN CLSCO 0 24 79 0 WRCOL O O HILITE TITLE WRCOLCFKEY ROW 1 0 3 SOLID WRCOL ROW 0 3 FKEYS i ROW TABLE START ROW i COL TABLE START COLUMN i w st LL WRCOLCROW COL 3 TABLE TOP HOW ROW 1 3 TABLE MIDDOLEI 321 WRCOLCROW COL 3 TABLE_M IDDLE ROW WRCOLCROW COL 3 TABLE MIDDLE TABLE MIDDLETI321 CHR 179 P gt ROW ROW 1 WRCOLCROW COL 3 TABLE TOP 2 HOW
32. 28 ESC 1 DEL 83 4 DEFAULT DRIVE C ERR ROW 25 i ERR COL 0 3 ROW 24 MESSAGE ROW 22 FILE ROW 22 FILE 10 TABLE START COLUMN 6 TABLE_START_ROW 2 ACTIVITY_MESS_ROW 24 MAX_PL J_POINTS 650 MAX INTERVALS 14 DEFAULT_SG_EXCITATION 4000 t 4000 mitivoltts 4 volts DEFAULT SG RANGE 11 5 mitivolt range DEFAULT_DT_EXCITATION 4000 i 4000 milivolts 4 volts DEFAULT DT RANGE 13 i 50 milivolt range HILITE 40 BLINK 83 LCD ME ESSAGE STRING 80 MESS_ARRAY ARRAY 0 10 OF MESSAGE REGISTERS RECORD E Bx CX DX BP St Dt DS ES FLAGS INTEGER CHANNEL RECORD RECORD INTEGER TRANSDUCER INTEGER t q sg 2 dt 0 undefined TRANSDUCER_COL INTEGER INTEGER DETAIL COL INTEGER EXCITATION INTEGER 1 CHANNEL INTEGER ROW INTEGER SR MAX REAL SR_MIN REAL i S_CALIB REAL 86 MVPERV CALIB REAL OFFSET REAL ULTIPLIER REAL ZERO CURRENT REAL 1 LO REAL 3 RANGE INTEGER END VAL ARRAY ARRAY 1 81 OF RECORD INDEX INTEGER VAL REAL t END PLOT_ARRAY 1 MAX_PLOT_POINTS OF REAL j PLOT CHANNELS ARRAYI 1 8 OF INTEGER HOUR INTEGER MINUTE INTEGER i SECOND INTEGER END VAR CURR PAGE BYTE MESS MESSAGE 4 ROW COL INTEGER CUR ROW CUR COL BYTE COLOR INTEGER
33. 399999 9 D ACQ_SCREEN WRCOL ACTIVITY_MESS_ROW 4 3 Checking channels 47 MESS 60 3 scan FOR K 1 TO NSCAN DO BEGIN WRCOLCACTIVITY_MESS_ROW 75 3 WRCOLCACTIVITY MESS ROW 75 3 1I TO ACCOUNTER COUNTER COUNTER 1 DUMP SINGLECDATA POINTS FOR 1 21 CHANNELS DO BEGIN J ACTIVE CHANNELSI 1 CHANNEL INFOLJ CURRENT DATA POINTSII CHANNEL INFOLJJ H lt DATA POINTSII J VAL THEN CHANNEL DATA POINTSI I1 VMAt IF CHANNEL INFOL J1 LO gt DATA POINTSITt1 VAL En THEN CHANNEL INFOL J1 LO DATA POINTSCI VAL END for k WRCOLCACTIVITY MESS ROW 60 3 2 CLSC 9 40 17 79 0 WRCOL 9 44 3 LO 3 WRCOL 9 57 3 AVERAGE INFOLJ CURREN 66 100 9 CURRENT 2 4 INFOC J 79 0 scanner MESS m o u m lt Ec e lt gt a lt e on e e m m m oa a gt i N tem gt gt on lt o o 2c a c cm em e 73 gt c c um e e O2 gt o c lt O Z 7 on om e o ou u 0 he d he 40 w wx mmm m gt o
34. 9 54 ADT Estimate 051 50000 Measured Estimoted 41000 V lt 25000 14000 5000 1950 1990 2030 2070 2110 2150 Yeor Figure 5 10 Fatigue Life Estimate Yeors 051 21 3 o u o whet 0 a 1950 1990 2050 2070 2110 2150 Year Figure 5 1l 55 estimated ADT versus the ADT calculated from Eq 5 5 using R 0 051 The agreement is seen to be fairly reasonable In addition to employing the measured ADT a capacity limit upon the ADT should be used This is necessary to prevent the ADT predicted from Eq 5 5 to exceed the absolute capacity of the highway This limit can be obtained from highway rating procedures or estimated based on observed conditions at peak traffic hours An estimated maximum value of 50 000 was used in Figs 8 through 10 resulting fatigue life prediction is shown in Fig 5 11 The estimated end of life is 2030 a fatigue life of 77 years The ADT limit of 50 000 is reached after 47 years the year 2000 The life estimates assume the ratio of stress cycles to number of vehicles remains constant over the life of the bridge The ratio used in the spreadsheet analysis is based on the average number of stress range cycles from the seven day field test 17 958 7 2565 cycles divided by the estimated ADT for 1988 for an R value of 0 051 The estimated 1988 ADT is 28 514 which results in 0
35. COM C 1 ELSE PUTC COM 2 READLNCAUX RESPONSE1 PUTC COMC X 16 SPONSE 1 SPONSE1 SPONSE2 m m m PROCEDURE DUMP SINGLE CVAR DATA POINTS ARRAY RESPONSE2 1 70 VAR RESPONSE RESPONSE2 RESPONSES MESSAGE J K INTEGER BEGIN 70 get a dump of readings PUTC COM CHR 13 READLNCAUX RESPONSETI READLNCAUX RESPONSE1 READLNCAUX RESPONSE2 IF CR21X CHANNELS 8 THEN READLNCAUX RESPONSE3 FOR 1 70 DO RESPONSESCI RESPONSE 1 1 10 RESPONSE3 0 CHR CR21X CHANNELS 10 IF CR21X_CHANNELS 8 THEN BEGIN FOR i 71 TO 80 DO RESPONSE3 I 1 CHR 80 END END ons Duce ues cuis edd e esq ues ieee te eee Ed 2 Ts PROCEDURE ACQ SCREEN BEGIN CLS 0 0 24 79 0 TITLE TEXAS STATE DEPARTMENT WRCOL O O HILITE TITLE WRCOL 4 4 3 Check Channels WRCOL 6 4 3 F2 Take Single reading WRCOL 8 4 3 F3 Take zero readings WRCOL 1O 4 3 F4A Zero the data logger WRCOL 12 4 3 F5 Capture Truck WRCOL 13 4 3 F6 Retrieve Truck data WRCOL 14 4 3 F7 Plot Truck data WRCOL 15 4 3 F8 Save Truck data WRCOL 17 4 3 F9 Start Rainflow routine WRCOL 18 4 3 F10 Retrieve Rainftow Data WRCOL 20 4 3 ESC Exit to main menu WRCOLCACTIVITY_MESS_ROW 1 0 3 SOLID_LINE
36. CUR 901
37. F2 SAVE DESCRIPTIONCFILE ROW FI LE COL F3 BEG CANCELLED FALSE ALL DEFINED AND CNOT CANCELLED DO BE N MESS I TO ACCURRENT CHANNEL DEFINE_MESSAGE 91 MESS 1 8 WRCOLCMESSAGE 0 3 MESSAGE DN FALSE WHILE NOT DN DO BEG N GETCCKEY IF CCHRC KEYO IN Y y N n OR KEY 27 THEN DN TRUE END IF KEY 27 THEN CANCELLED TRUE ELSE IF CHRCKEYO IN Y THEN ELIMINATECCURRENT CHANNEL ELSE CANCELLED TRUE END IF NOT CANCELLED THEN BEGIN EMPTY TRUE FOR 1 1 TO 8 DO DEFINEDCI THEN EMPTY FALSE IF EMPTY THEN BEGIN WRCOL MESSAGE_ROW 0 BLINK EMPTY_MESSAGE YOT GETCCKEY a ROW 0 MESSAGE_ROW 79 0 ELSE BEGIN WRCOL MESSAGE_ROW 0 BLINK SENO_MESSAGE SEND PROGRAM Puno b 0 55 79 0 END F5 BEGIN SR TABLE UPDATE SCREEN SR ENO ESC BEGIN DONE TRUE CR21X CHANNELS 0 FOR CHANNEL 1 TO 8 DO BEGIN IF DEF INEDC CHANNEL THEN BEGIN CR21X_CHANNELS 2 1 CHANNELS 1 ACTIVE CHANNELS CHA 95 CHANNEL END END t CURR_PAGE 20 SEL PAGE j CLSCO 0 24 79 0 END DEL ELIMINATECCURRENT CHANNEL ELSE BEGIN CASE CURRENT FIELD OF 1 CURRENT FIELD 2 2 BEGIN IF CHANNEL INFOC CURRENT CCHANNEL 1 DETAIL gt 7 THEN CURRENT FIELD 3 ELSE CURRENT FIELD 1 END 3 CURRENT FIELD 4 CURRENT F IELD 1 ENO
38. KEY_PRESSED BYTE FNAME 501 PF_FOUND BOOLEAN i NEW PF BOOLEAN SOLIO LINE MESSAGE ERRORS MESS ARRAY BOOLEAN SCREEN_SET BOOLEAN ACQ_SCREEN_SET BOOLEAN LAST_NUM REAL LAST CHAR CHAR SERIAL_PORT gt TEXT t CH CHAR CHAR AVAIL BOOLEAN FULL_DUPLEX BOOLEAN INTEGER LINE MODEM BYTE DESCRIPTION FILE TEXT DATA FILE TEXT 4 TRUCK DATA TEXT STK FILE TEXT 8 REGS REGISTERS BAUD INTEGER PARITY INTEGER NSTOP INTEGER INTEGER CANCELLED BOOLEAN EMPTY BOOLEAN PROGRAMME D BOOLEAN ZEROED BOOLEAN TITLE MESSAGE TABLE_TOP MESSAGE 3 TABLE_TOP_2 MESSAGE i TABLE MIDOLE MESSAGE TABLE_LINE MESSAGE TABLE BOTTOM MESSAGE FKEYS MESSAGE S CALIB MESSAGE MESSAGE i MVPERV CALIB MESSAGE MESSAGE i 66 09 TRANS MESSAGE MESSAGE DETAIL MESSAGE MESSAGE SR 5 lt MESSAGE SR MIN MESSAGE MESSAGE SEND MESSAGE MESSAGE READ MESSAGE MESSAGE DEF INE MESSAGE MESSAGE EMPTY MESSAGE MESSAGE CHANNEL INFO ARRAYL1 81 OF CHANNEL RECORD RAW VOLTAGES ARRAY 1 81 OF REAL ACTIVE CHANNELS ARRAY 1 81 OF INTEGER RAIN ARRAY ARRAYL1 201 OF MESSAGE SRMAX SRMIN 1 71 OF REAL CURRENT TIME T ME CR21X START TIME TIME DAYS_ELAPSED INTEGER INTERVALS ELAPSED I NTEGER i RAIN_INTERVAL INTEGER CURRENT CHANNEL INTEGER CURRE
39. Main Menu 25 secondary menus use the 5 key It is not possible to move directly from one secondary menu to another secondary menu To illustrate the use of the program an example test will be discussed The appropriate steps for conducting the example test will be given with the discussion of each of the program functions The example test will involve taking both single truck continuous and rainflow type data at two locations on a bridge The first location is a category C weld detail and will be instrumented with two strain transducers The second location is a category E weld detail and will be instrumented with one strain transducer and one strain gage The test data sheet is shown in Figure 4 2 Assuming that the equipment is set up properly as discussed in Section 3 6 the steps necessary to execute the example test will be discussed in the following sections and will be listed in Section 4 5 4 2 Channel Description The first step in executing a test is to input the channel description data This is done using the channel description screen shown in Figure 4 3 The channel description data is used to tell the Campbell which of the eight input channels will be active and what type of instrumentation will be connected to each channel The channel description screen is accessed from the main menu using the F5 key The arrow keys at the bottom right corner of the keyboard can be used to move around the screen The followin
40. O OoOOomm gogo oo mmm em FS GER wy v a dees ex wf qaw PROCEDURE GET NUMBER OF CHANNELS VAR RESPONSE MESSAGE J INTEGER CH CHAR ASCI 5 71 BEGIN GO_REMOTE WRS COM 6AA READLNCAUX RESPONSE READLNCAUX RESPONSE FOR I 1 TO 7 DO 5 11 11 RESPONSE 1 3 5 01 CHR 7 CR21X CHANNELS ROUND A TO F ASCII12 WRS_COM 0Q READLN AUX RESPONSE READLNCAUX RESPONSE READLNCAUX RESPONSE END w x qt ee W ub ub w 99 G6 INTEGER CHAR MESSAGE VAL _DATA INTERVALS K RAINFLOW DN POINTS J DONE TEMP NAME MINUTES CH PROCEDURE RETRIEVE VAR RESPONSE DATA PROCEDURE SAVE VAR CHANNEL I NFOI m a a e e e ve eo gt i gt gt gt e gt k O he o c o c e 2 e e a 73 a c a gt o uJ m u er O e 2 e gt D gt Land o gt eU a E m a e e 20 lt gt m lt e lt gt N cx m a E T 0 ona do
41. OR KEY PRESSEO RT ARROW OR KEY PRESSED OR KEY PRESSED F2 OR KEY PRESSED F3 OR KEY PRESSED F4 OR KEY PRESSED F5 OR CKEY_PRESSEO F6 OR KEY PRESSED F7 OR KEY PRESSED F8 KEY PRESSED F9 OR KEY PRESSED F10 OR KEY PRESSED ESC OR KEY PRESSED DEL THEN SP CIAL TRUE END lt PROCEDURE DISP ERRCERR INTEGER VAR CUR ROW CUR COL BYTE BEGIN CURSORCCUR ROW CUR COL WRCOL ERR ROW ERR COL 4 ERRORSTERR WRCOLCERR COL 8 ERRORS 0 5 ROW CUR COL END PROCEDURE DIG INTEGER VAR DONE BOOLEAN KI Y BYTI DEGIN DONE FALSE WH tB NOT DONE DO BEGIN GETCCKEY CNUMERICCKEY THEN BEGIN END ELSE IF S FUNCTION LEGAL CCCH BYTE BOOLEAN BEGIN LEGAL C FALSE IF CCH gt 48 AND CH lt 57 OR gt 64 AND CH lt 90 OR CCH gt 95 AND 6 lt 123 OR CCH gt 35 AND CH lt 39 OR CH 33 OR CH 2 125 OR CH 126 THEN LEGAL TRUE END cs Sk a et a ol PROCEDURE GETNAM VAR CB ROW COL e BYTE FLEN ELEN INTEGER DONE BOOLEAN BOOLEAN NAME STRING 501 BEGIN GET CURSORCROW COL FOR 3 TO 50 DO NAME Ee M on DO
42. TNUMCTEMP _REAL 2 0 IF REAL gt 9999 0 THEN CURRENT T ME HOUR ROUND TEMP REAL TEMP _ REAL 9999 0 WRCOL CROW COL CPU new minute CURSOR ROW COL 69 GETNUMCTEMP_REAL 2 0 IF TEMP REAL gt 9999 0 THEN CURRENT TIME MINUTE ROUNDCTEMP_REAL CURRENT_TIME SECOND 0 REGS DO BEGIN AX 2000 CX CURRENT_TIME HOUR 256 CURRENT TIME MINUTE DX CURRENT TIME SECOND 256 MSOOS REGS END CL s ROw cOL ROW COL 72 0 i N PROCEDURE INIT_SR_TABLE BEGIN SRMAX 1 28 0 SRMAX 2 20 0 SRMAX 3 16 0 SRMAXI 4 16 0 SRMAX 5 14 0 SRMAX 6 9 0 SRMAX 7 5 0 SRMIN 1 3 0 SAMIN 2 2 0 SRMINI31 1 0 3 SRMIN A 1 0 SRMINI 5 1 0 i SRMIN 6 0 5 SRMINI7 0 8 8 5 d zz e den cca rom om aag u euo o One 5 D OF gt user ESC to canc thru 99 for or 9 U Erase Channe nim Transducer Del or T for and E or e h 1 p e h 1 P T RU d g h h n e y 5 t n Send File e F3 147 incomp INITIALIZE PROCEDURE VAR INTEGER ROW COL INTEGER CHANNEL ROWS BEGIN SR E INIT TABLE ar P ewm 7 ue lt Cr c c o a TIIT t ve ae an ne
43. V Details C no Type max min re os pem m Lr uw ww 4 Message Line F1 Load File F2 Save File F3 Send File Del Erase Channel ESC Exit Undefined FIGURE 4 4 Example Channel Description Data GE 88 TEXAS STATE DEPARTMENT HIGHWAYS AND PUBLIC TRANSPORTATION F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 ESC Check Channels Take Single Reading Take Zero Reading Zero the Data Logger Capture Truck Retrieve Truck Data Plot Truck Data Save Truck Data Start Rainflow Routine Retrieve Rainflow Data Exit to main menu Waiting for command Fig 4 5 Data Acquisition Menu 34 will include the offsets used in the zeroing process If the data are far from zero gt 1 0 MV V then a good zero has not been obtained and the Campbell should be rezeroed 4 3 2 F2 Take Single Reading This function is similar to the Check Channels function It instructs the Campbell to take data and then retrieve and display it However unlike the Check Channels function it only retrieves one data point instead of retrieving several points and averaging them advantage of this function is that it is much quicker than the Check Channels It only takes a few seconds to execute single reading function also differs from the check channels function in that even if the channels have been zeroed the F2 function will always give the raw data read directly from
44. an increase the percentage of threshold stress range to be used 5 2 Program RFLO In order to facilitate reduction of the stress range data gathered in the field an additional program is provided The program title is RFLO This program is written in Turbo Pascal RFLO can be used to plot the stress range and the fatigue damage factor for 45 each channel and collection interval on the screen In addition the user can print out the data for further study and documentation The program will also create comma separated files in which the printed data is written to a disk file with each value separated by a comma This comma separated file can then be used as input into other programs such as commercial spreadsheet programs detailed description of how to use this program and interpretation of its output is given in the next section Data File 35 Save File C 135 11 Number of intervals 7 Interval Length 1440 Minutes Number of channels 5 SR Max SR Min Channel 1 9 000 0 500 Channel 2 9 000 0 500 Channel 3 9 000 0 500 Channel 4 9 000 0 500 Channel 5 9 000 0 500 Interval 1 Channel 1 Fi SUM MSL vs SR F2 D F vs SR F4 PRINT F5 SAVE ESC END F7 SAVE ALL F8 PRINT ALL FIGURE 5 1 RFLO Input Screen 5 2 1 Using Program RFLO The program is executed from DOS by typing RFLO followed by a carriage return The prompt Data File will then appear on the screen Enter the data file you wish to work
45. life of steel girder bridges The bridge testing system has been designed so that it can be easily installed a bridge in less than a day and can record data automati cally for up to two weeks The system has been enclosed to protect the electronic components from the environment and the entire system can be clamped onto a bridge girder The main components of the system are a Campbell Scientific eight channel datalogger and a Data General portable computer The Data General computer is used to program the Campbell to record strains measured using conventional strain gages or special clamp on strain transducers The system is very flexible with respect to the types of data that can be collected and programs have also been written to analyze the data This user s manual has been written to provide the information required to conduct a bridge test 17 Key Words 18 Distribution Statement automated testing residual fatigue No restrictions This document is life steel girder bridges data available to the public through the strain gages transducer Campbell National Technical Information Service Scientific eight channel datalogger Springfield Virginia 22161 19 Security Classif of this report Security Classif of this page 21 No of Pages Unclassified Unclassified 118 Form DOT F 1700 7 8 69 ESTIMATING RESIDUAL FATIGUE LIFE OF BRIDGES by G Jeff Post Karl H Frank and Bahram Alec Tahmassebi Research R
46. lt gt 6 0 t file specified NCDESCRIPT ION FILE FNAME CDESCRIPTION FILE lOresult 0 DONE WRCOLCROW COL 25 4 File Not Found Reading Data 920 FILE START TIME HOU DO ACTIVE _CHANNE 222020 7070720 M SS xd ce o 2 m z INTERVAL 1 f inactive O x x rm D O G gt I Pbro mo m D i gt 2 3 vt loaded DEFAULT SG EXCI TATION gt DEFAULT SG RANGE CHANNEL 1 1 21 CITATION CHANNELS new zeroes need be taken new program needs to be CHANNELSICHANNELS AXI CHANNEL INC CHANNEL CHANNELS M M EGIN END INTEGER END PROGRAMMED gt TRUE lt gt CHR 0 DESCRIPTIONCROW END ELSE DONE DONE DN FOUND T PL CFNAMETO TH UNT VAR PROCEDURE SAVE BOOLEAN u STR INTEGER CHAR PROCEDURE RECORD DONE i CH INFO VAR CHANNEL INTEGER BEGIN WRCOLCROW COL 25 4 Please wait Saving file to disk REWRITECXCDESCRIPTION FILED WRITELNCDESCRIPTION FILE START TIME HOUR 2 START TIME MI
47. me wiy MEM Gum M Ue ec amm GR GER des GS mb a ARR GE Gub db g PENN DION ALL DEFINED BOOLEAN CHANNEL INTEGER OEFINED BOOLEAN BEGIN DEFINED TRUE CHANNEL 1 WILLE CHANNEL lt 8 ANO DEFINED DO GIN IF CC CCHANNEL_ NFOL CHANNEL TRANSDUCER 0 AND CHANNEL INFOLCHANNEL DETAIL z 0 AND CHANNEL INFOLCHANNEL SR MAX lt 0 0 AND CHANNEL_INFC CHANNEL SR_MIN 0 0 AND CHANNEL 5 CALIB lt 9999 0 AND CHANNEL INFOLCHANNELI MVPERV CALIB lt 9999 0 OR CCHANNEL INFOLCHANNELI TRANSDUCER lt gt 0 AND CHANNEL INFOLCHANNEL1 DETAIL 0 AND CHANNEL INFO CHANNEL 1 SR MAX gt 0 0 AND CHANNEL_ NFO CHANNEL 5 MIN gt 0 0 AND CHANNEL I NFOLCHANNEL1 S CALIB gt 9999 0 AND CCHANNEL INFOL CHANNEL MVPERV_CALIB gt 9999 0 THEN DEFINED TRUE ELSE BEGIN DEFINED FALSE CHANNEL_INFO CHANNEL TRANSDUCER 0 THEN BEGIN CURRENT_CHANNEL CHANNEL CURRENT FIELD 1 END ELSE CHANNEL INFOLCHANNELJ DETAI IL 0 THEN BEGIN CURRENT CHANNEL CHANNEL eS r ee 4 ELSE CHANNEL 1 5 MAX lt 0 0 THEN BEG N 58 CURRENT 6 CHANNEL CURRENT FIELO 5 END ELSE IF CCHANNEL_INFOCC
48. mounted near the right side of the Campbell box and connected into one of the two pin connectors The Data General also connects into the right side of the Campbell box Figure 2 3 shows the location of these connectors on the box Once the Data General and the battery have been connected programming of the Campbell can begin regardless of whether the transducers have been connected The cables from the transducers and strain gages connect into the left side of the Campbell box The eight connectors correspond to the eight input channels as shown in Figure 2 2 The cables should be wrapped around a C clamp or a secondary bridge member near the Campbell box so that the cable weight will not be pulling on the connector The same should be done for the connectors at the transducers and strain gages The cables should be pulled tight to prevent them from hanging below the girder When installing the transducers the C clamps should be tightened by hand as tightly as possible to insure that no slipping occurs When strain gages are used the strain FIGURE 3 3 Equipment Set up 21 22 gage completion boxes should be clamped to the girder and the connection to the gage should be insulated from moisture After all of the equipment has been connected two checks can be made to see if the Campbell is working properly On the right side of the campbell box is a voltage meter which can be used to check that power is getting to the Campbell The b
49. of the data can be obtained by pressing the F4 key F4 will print out the current interval and channel The printout for all intervals and channels is obtained by pressing the F7 key typical print is shown in Figure 5 2 The headings on the printout are defined as follows SRL stress range level MSL1 number of cycles recorded in mean stress level 1 MSL2 number of cycles recorded in mean stress level 2 SUM total number of cycles recorded in both mean stress levels SR stress range in ksi for the given SRL MSL1 percent of the total number of cycles recorded that are in the mean stress level 1 MSL2 percent of the total number of cycles recorded that are in the mean stress level 2 PALL percent of the total number of cycles recorded that are in the particular SRL damage factor see Eq 5 4 In addition to the printing analysis and saving functions the program provides for a graphical display of the data on the screen Pressing F1 produces a bar graph his togram of the level of occurrence of the stress ranges The levels at the two mean stress levels are added together to produce this plot Pressing the F2 key produces a plot of the 47 Interval 1 Channel 1 SRL MSL1 MSL2 ALL D F SR MSL1 MSL2 SUM 9 o gt s o o e o 400 207 78
50. read 50 millivolt range input channel number for transducer use excitation channel 1 4000 mV excitation use storage location 1 use multiplier of 1 use offset of 0 exit programming table begin taking data display transducer reading in mV V FIGURE 3 2 Transducer Calibration Program 18 power can be disconnected from the Campbell and then reconnected and the programming started again from the beginning Additional information on programming the Campbell can be found in the Campbell User s Manual After the Campbell has been programmed the calibration test can begin The transducer reading at zero load should be recorded and then load should be applied in 1 kip increments up to approximately 6 kips 8 ksi The Campbell will continuously display the output of the transducer in MV V Transducer and load readings should be taken at each increment The same procedure should then be followed for unloading The test loading should not exceed six kips because the configuration of the transducers causes stress concentrations which can lead to local yielding of the transducers at higher load levels After the load has been removed the transducer should be moved to the other side of the calibration bar and the test repeated The results of the two tests should be averaged in order to remove the effects of any bending that might be occurring in the specimen The required transducer calibration data can then be determined by plotting the
51. readings can be converted to stress using the following formula Stress Sr Max output 95 36 where Sr is the value entered on the channel description for the maximum stress expected for this particular channel To remove the plot from the screen press any key The F7 function may be repeated as many times as desired 4 3 8 F8 Save Truck Data The F8 key is used to save the data onto the DG hard disk If the data are not saved using the F8 function before the F6 Retrieve Truck Data function is used again or before the program is exited the data will be lost When the F8 key is pressed the DG will ask for a filename and a filename should be entered with no file extension The DG will assign a file extension of STK Single TrucK If a filename of EXA is entered the data will be stored in file EXA STK 4 3 9 F9 Start Rainflow Routine The F9 function is used to program the Campbell to take rainflow data for use in fatigue analysis In the rainflow mode the Campbell counts the number of stress cycles measured during a specified period of time Rainflow refers to the technique that is used for counting the cycles The cycle counts are stored in a two dimensional histogram with the cycle amplitudes on one axis and the mean cycle magnitudes on the other axis The histogram is 2 by 50 with 2 mean cycle rows and 50 amplitude columns For specific details on the Campbell rainflow program see Instruction 81 in the Campbell ma
52. the strain gages or transducers 4 3 3 F3 Take Zero Reading When the strain gages and transducers are installed they will not produce a zero electronic output It is necessary to subtract these initial non zero outputs from each channel so that all of the channels will read zero stress under the same conditions and also to allow the full dynamic range of the Campbell to be utilized This is referred to as zeroing and must be done before running a test Zeroing is accomplished using the F3 and F4 functions The F3 function instructs the Campbell to take data for a few seconds and the DG then retrieves the data for each active channel The data are then averaged and displayed for each channel These average values are saved by the DG and are used to zero the Campbell when the F4 function is used The F3 key should be pressed when there is relatively little traffic on the bridge Some automobile traffic is acceptable but no truck traffic should be on the bridge when the zero readings are taken If a truck should enter the bridge while zero readings are being taken the zeroing function should be repeated by pressing the F3 key after the current zeroing operation is complete 4 3 4 F4 Zero The Data Logger After satisfactory zero readings have been taken using the F3 key the Campbell must be reprogrammed using the zero values The F4 function is used to accomplish this Pressing the F4 key instructs the DG to reprogram the Campbell using a multipli
53. 2 4 1 DO FRACR FRACR 10 0 A F SIGN WHOLE FRACR gt O Hone FUNCTION COM READY BOOLEAN VAR LINE MODEM I J INT REGS REG BFGIN COM READY REGS AX REGS DX INTRCS 14A LINE MODEM WRITELN READY LINE tINE 3 MODEM MODEM 3 LINE LINE AND 01 WRITELN LINE IF CLINE AND 01 1 THEN COM READY TRUE EG H L und 69 PROCEDURE COM PAR CBAUD PARITY STOPS NDATA INTEGER VAR adu s BYTE J INTEGER REGS REGISTERS BEGIN PARAMETERS CASE BAUD OF 110 PARAMETERS 00 150 PARAMETERS 20 300 PARAMETERS 40 600 PARAMETERS 60 1200 PARAMETERS 80 2400 PARAMETERS AO0 4800 PARAMETERS CO 9600 PARAMETERS 5 END case CASE PARITY OF 0 PARAMETERS PARAMETERS 00 none 1 PARAMETERS PARAMETERS 08 odd 2 PARAMETERS PARAMETERS 18 even END i case CASE STOPS OF 1 PARAMETERS PARAMETERS 00 2 PARAMETERS PARAMETERS 04 END case 3 CASE NDATA OF 7 PARAMETERS PARAMETERS 02 8 PARAMETERS PARAMETERS 03 END case REGS 0000 PARAMETERS REGS DXK 0000 INTRC 14 REGS END PROCEDURE SET PAR BEG N CURR PAGE z 1 SEL PAGE CLSCO 0 24 79 0 WRCOLC1
54. 40 3 Communications Parameters WRCOL 2 40 3 3 WRCOL 24 1 3 F1 Baud F3 Parity F5 Stop Bits F7 Data Bits ESC Exit WRCOL 5 40 3 Baud Rate CASE BAUD OF 110 WRCOLC5 52 3 110 150 WRCOL 5 52 3 150 9 300 WRCOL 5 52 3 300 600 WRCOL 5 52 3 600 3 1200 WRCOL 5 52 3 1200 2400 WRCOL 5 52 3 2400 4800 WRCOL 5 52 3 4800 9600 WRCOL 5 52 3 9600 END f case 12 WRCOL 6 40 3 Parity CASE PARITY 0 WRCOL 6 49 3 None 1 wRCOL 6 49 3 O0dd 2 WRCOL 6 49 3 Even END f case WRCOL 7 40 3 Stop Bits CASE NSTOP OF 1 WRCOLC7 52 3 1 2 WRCOL 7 52 3 2 END case 3 WRCOL 8 40 3 Data Bits CASE NDATA OF 7 WRCOL 8 52 3 7 8 wWRCOL 8 52 3 8 END case OL KEY 127 GETC KEY WHILE KEY PRESSED lt gt ESC DO BEGIN CASE KEY PRESSED OF F1 BEGIN CASE BAUD OF 110 BAUD 150 150 BAUD 300 300 BAUD 600 600 BAUD 1200 1200 BAUD 2400 2400 BAUD 4800 4800 BAUD 9600 9600 BAUD 110 END case CASE BAUD OF 110 WRCOL 5 52 3 110 150 WRCOL 5 52 3 150 i 300 WRCOL 5 52 3 300 9 600 WRCOL 5 52 3 600 1200 WRCOL 5 52 3 1200 2400 WRCOL 5 52 3 2400 4800 WRCOL 5 52 3 4800 9600 WRCOL 5 52 3 9600 END E case END t Fil F3 BEGIN CASE PARITY OF 0 PARITY 1 1 PARITY 2
55. 40 minutes 1 day 1420 current time start time of test save rainflow description in file exrfl 21x return ESC return to main menu ESC exit 21X program disconnect DG return at end of rainflow test and reconnect cd campbell change to campbell directory 21x execute 21X program F9 enter data acquisition mode F10 retrieve rainflow data read rainflow description file retrieve and save data return ESC return to main menu ESC exit 21X program copy exr l rfl a make backup copy of rainflow data on floppy disk FIGURE 4 6 Example Test cont CHAPTER FIVE ESTIMATION OF REMAINING FATIGUE LIFE 5 1 Background The data gathered during a field study of bridge can be used to provide a realistic estimate of a structure s fatigue life The stress cycles measured in the field are stored in a two dimensional array for each period of collection and data channel in the Campbell These arrays are then transferred to Data General microcomputers where the data is retrieved The array contains the number of stress range cycles which occurred at each of the fifty stress range increments and two mean stress levels for each channel and period The stress range level and number of cycles can be used to estimate the fatigue damage using a Miner s rule summation to calculate the effective stress range as shown below Sre qv Sh 3 5 1 where n T the number of cycles at stress range Sp
56. 9 Pm ee T am CG K u u x T lt Z lt Z lt Z lt O C x ARS PI A gt N I I IN II mA on mS oem WFR OA 6269269 63 PA wm 0000000 00000000 2 222329 0aco0dcgodgdao aoa CN c7 c7 v T pr m p re o m e w w que qu qe m m F w w w w O u O u Ou V A oO eee VU I e VS AR O 222222 Z gt 2222 Q 2 22 2 2 27 CIILILILLII IIIIIIII IIIILILIII aaqa lt lt lt lt lt lt M po j lt OOOOOOO OOOOOOOO OOOOOOOO0 2 SII Wu Bon oy gon uon on nou H H H Hon nort Don H H Hos oH n Hou NH H u ft H qn 2 Z Z Lew ss r 4 se 9 ee se sa 2 0 e 2 gt 22 22 22 te ee ne LL
57. BEGIN J ACTIVE CHANNELSII WRITECTRUCK DATA J 1 END WRI TELNCTRUCK_ DATA COUNTER NSCAN FOR SCAN 1 TO NSCAN DO BEGIN WRCOLCACTIVITY_MESS_ROW FILE_COL 62 3 WRCOL ACTIVITY_MESS e FILE COL 62 3 1 TO ACCOUNTER i1 COUNTER COUNTER FOR 1 TO CR21X CHANNELS DO BEGIN J ACTIVE CHANNELSII DATA PLOT DATALJ SCAN1 10 5 3 WRITELN TRUCK_DATA END CLOSE TRUCK_DATA CLSCACTIVITY_MESS_ROW 0 ACTIVITY_MESS_ROW 79 0 END record BEGIN DONE FALSE REPEAT IF FNAME O1 lt gt CHR O THEN BEGIN FOR 1 TO OROCFNAME 01 2 DO TEMP NAME 1 4121 END SR _ CHR CORDCFNAME 01 2 CLSCACTIVITY MESS 0 ACTIVITY MESS ROW 79 0 WRCOL CACTIVITY MESS ROW FILE COL 3 Save File CURSOR CACTIVITY MESS ROW FILE 12 CHR O GETNAM L0 gt CHR 0 file specified H 6 2 2 i du 3 lOresult 0 IOO m aa orri gt O mc T o file exists 1 WRCOLCACTIVITY MESS ROW FILE COL 25 4 Filfe exists Overwrite Y or N ON FALSE WHILE NOT DN DO BEGIN GETC CKEY UD t Y y N n THEN ON TRUE E IF CHR KEY IN Y y THE overwite file EGIN RECORD_INFO DONE TRUE END END then ELSE BEGI
58. E 2 1 Campbell 21X Box FIGURE 2 2 Campbell Box Connector Numbers voltmeter battery FIGURE 2 3 Right Side of Campbell Box Input Channel Numbers ip _ ss ERESNZEAEANJN Campbell Input Channels De Excitation FIGURE UN Channels 12 2 4 Campbell Box Wiring Diagram Battery Inputs FIGURE 2 5 Battery Box 10 FIGURE 2 7 Transducers Completion Boxes and Case 11 completion boxes The transducers were manufactured by Bridge Weighing Systems Inc The transducers include four 350 ohm strain gages wired in a full bridge configuration and provide a mechanical amplification of approximately 7 5 The strain gage completion boxes contain three 120 ohm resistors for use with 120 ohm strain gages The resistors are manufactured by Micro Measurements and are guaranteed to have a resistance within 01 of 120 ohms The completion boxes have been sealed to protect the circuit from moisture and should not be opened unless repairs are necessary 2 2 5 C Clamps and Tool Box C clamps are used to fasten the Campbell and battery boxes to the bridge girder They are also used to clamp down the transducers and completion boxes Thirty 3 inch clamps have been provided for this purpose tool box has also been provided for storing and carrying the clamps Space is also available in the tool box for additional tools as required 2 9 0 Cables and Connectors Approximately 1000 f
59. EGER CHAN INTEGER YMAX YMIN REAL ROW COL INTEGER BEGIN XMAX NPOINTS XMIN i XLEN XMAX YMAX 9999 9 1 9999 9 FOR 1 TO CHAN DO BEGIN CHAN PCHAN FOR J 1 NPOINTS DO BEGIN IF PLOT gt YMAX THEN YMAX PLOT_DATA CHAN J IF PLOT 1 lt YMIN THEN YMIN PLOT_DATAL CHAN J END YLEN ABSCYMAX YMIN IF YLEN 0 0 THEN YLEN ABS YMAX XSCALE 639 0 XLEN YSCALE 199 0 YLEN IF YMAX lt gt YMIN THEN WRCOL 24 0 3 F TO ACYMIN 5 40 1 WRCOL O 0O 3 F TO ACYMAX 5 4 FOR 1 CHAN DO BEGIN CHAN PCHANII FOR J 1 TO NPOINTS 1 DO BEGIN X1 J ROUNDCXSCALE 1 ROUNDCCYMAX DATA CHAN 1 YSCALE X2 J 1 ROUNDCXSCALE Y2 ROUNDCCYMAX DATACCHAN J 11 YSCALE i DRAWCX1 Y1 X2 Y2 3 DELAY 25 END END END 6S Se oe oe ee Se oso mme I eh SS SS eS See Se e Pe ei m dii TRANSLATECLINE MESSAGE VAR NVAL INTEGER VAR VALUES VAL ARRAYO VA t J INTEGER PTR INTEGER INTEGER ASCII STRINGIS BEGIN PTR a ne NVAL 0 WHILE PTR lt ORDCLINELO DO BEGIN NVAL NVAL 1 VALUESINVAL1 INDEX CCORDCLINETPTR 48 10 CORDCLINELIPTA 1 48 06 FOR J 1 TO 6 DO ASC
60. EGIN GO REMOTE DELAYC200 COMC 1 COM A PUTC COMC D PUTC_COM 0 1 COM 2 PUTC_COM 5 PUTC COMCCHRC I PUTC COM 6 COMCCHR 13 PUTC COM 2 PUTC COMCCHR 132 PUTC COMC 1 1 COMC 1 PUTC COMCCHRCT D COMC 1 PUTC COMCCHR C132 PUTC_COM 1 PUTC COMt CHR C130 _COM 2 PUTC_COM 0 0 0 PUTC COMC 1 PUTC COM CHR PUTC_COM 7 R R C 96 me Ll l oe SAN SA 132 PUTC_COM CH PUTC_COM 2 PUTC COM PUTC COM 5 PUTC COMCCH 2 13 3 13 Ar 3 13 L DEFINED CHANNEL INTEGER BOOLEAN CCCHANNEL INFOLCHANNEL 1 TRANSDUCER CHANNEL iNFOL CHANNEL 1 DETAIL CHANNE NFOLCHANNEL1 SHR MAX n OL CHANNEL1 SR MIN D J i gt TRUE NE PROCEDURE LOAD_FILECROW COL INTEGER VAR DONE BOOLEAN TEMP NAME STRING I 501 CHANNEL INTEGER t INTEGER CH CHAR BEGIN gt FALSE i lt gt CHR O2 FOR I 1 TO 022 2 DO 51 NAME 11 2 TEMP _NAME O CHRCORDCFNAMET 0 2 ROW COL 3 Data File ROW COL 12 CHR 0 1
61. END f for 3 WRCOLCACTIVITY MESS ROW 60 3 9 CLS 9 40 17 79 0 wRCOL 9 62 3 Z2ERO FOR I 1 TO 21 CHANNELS DO BEGIN J ACTIVE CHANNELS I1 CHANNEL NFOLJJI ZERO CHANNEL INFOLJJ ZERO NSCAN CHANNEL INFOLJI ZERO CHANNEL INFOLJ ZERO CHANNEL CHANNEL INFOLJ MULTIPLIER WRCOL 9 1 55 3 I TO ACJ A CCHANNEL INFOCJ ZERO 2 4 N 3 CLSCACTIVITY_MESS_ROW 0 ACTIV ITY_MESS_ROW 79 0 CURSORCACTIVITY_MESS_ROW 0 END 1 BEGIN 4 zero the campbell 3 FOR 1 TO CR21X CHANNELS DO BEGIN J ACTIVE_CHANNELS 1 CHANNEL INFOL JJ MULTIPLIER 95 0 CHANNEL INFOLJJ S CALIB CCHANNEL 1 58 MAX X CHANNEL a ONNEN INFOC J OFFSET 5 CHANNEL_INFO J ZERO CHANNEL IN 55 0 3 description must be saved updat G CLSCACTIVITY MESS MESS ROM 79 0 SAVE DESCRIPTIONCACTIVI TY MESS ROW 0 WRCOLCACTIVITY MESS ROW 0 BL INK SEND M SSAGE 1 SEND PROGRAM CLSCACTIVITY MESS ROW 0 ACTIVITY MESS ROW 79 0 1 CURSORCACTIVITY MESS ROW 0 ACQ SCREEN END t 1 BEGIN t dade truck WRCOLCACTIVITY MESS ROW 4 3 lnitializing the data logger TOGGLE RECORD 2 ACQ_SCREEN CLSCACTIVITY_MESS_ROW 0 ACTIVITY_MESS_ROW 79 0 CURSOR ACTIVITY_MESS_ROW 0 WRCOLCACTIVITY_MESS_ROW 4 3 Capturing Data Press any key to stop 4
62. HANNEL SR_MIN 0 0 THEN BEGIN CURRENT_CHANNEL CHANNEL 6 ELSE iF CCHANNEL 1 5 CAL B lt 9999 0 CURRENT CHANNEL CHANNEL CURRENT FIELD gt 2 END ELSE CCHANNEL_INFOC CHANNEL MVPERV_CALIB lt 999 THEN BEGIN CURRENT_CHANNEL CHANNEL CURRENT FIELD 3 END END f else CHANNEL CHANNEL 1 END f while ALL_DEF INED DEFINED END p SS SH SSS SSeS cidem SSS omo dm en ur ee Seer SSeS Se ee Se SS 1 JUMP_TO LOCATION INTEGER VA INTEGER RESPONSE1 MESSAGE BEGIN INIT CAMPBELL wRS TO ACLOCATI OND2 PUTC COM PUTC COM PROCEDURE ERASE PROGRAM VAR I INTEGER BEGIN GO REMOTE WRS COM AAAAS978A FOR I 1 TO 200 DO DELAY 100 GO REMOTE END PROCEDURE SEND PROGRAM VAR CHANNEL INTEGER INPUT LOCATION INTEGER INITIAL LOC INTEGER BEGIN PROGRAM GO REMOTE WRS COM AA2434A WRS COM X1A WRS COM 00125A 98 write of channels to WRS COM 30A COM I ACCHANNEL S2 5 COM A WSS 1A INPUT _LOCAT ON 2 CHANNELS O FOR CHANNEL 1 TO 8 FOR CHANNEL 1 TO 8 DO input location 1 3 DO ACTIVE_CHANNELS CHANNEL 1 1 inactive
63. I I J 5 LINELPTR 1 Jl ASCII O CHR 86 VALUES NVAL VAL A TO F ASCII PTR PTR 10 END 1 RESPONSE2 MESSAGE J INTEGER OK BOOLEAN BEGIN OK FALSE WHILE NOT OK DO BEGIN PUTC_COMC A PUTC__COMCCHR 13 READLNCAUX RESPONSE1 READLNCAUX RESPONSE2 IF RESPONSE2 2 R THEN OK TRUE ELSE 1 ene i WHILE NOT D Sas IN 15 2 8 4 5 877 AND l lt BO DO 1 J WHILE RESPONSE2C 11 lt gt DO BEGIN RESPONSE1 J RESPONSE2 1 J J 1 J 1 END RESPONSE1 0 CHRCJ 1 DSP ROUND A_TO_F RESPONSE1 WHILE RESPONSE2 11 lt gt L DO i 1 l P 2 J oas To WHILE RESPONSE2T i lt gt DO BEGIN RESPONSEI1 J RESPONSE2T 1 J J 4 1 3 J l 1 3 END RESPONSE1 01 CHR J 1 ROUNDCA_TO_FCRESPONSE1 IF MPTR gt DSP THEN NSCAN 14588 DSP MPTR DIV CR21X CHANNELS 1 ELSE NSCAN DSP MPTR D V CR21X_CHANNELS 1 END 6 PROCEDURE TOGGLE_RECORD MODE INTEGER VAR RESPONSE1 RESPONSE2 MESSAGE CH CHAR BEGIN GO REMOTE READLNCAUX RESPONSE 1 PUTC COM 6 PUTC COMC A READLNCAUX RESPONSE1 COMC D READLNCAUX RESPONSE 1 IF MODE 1 THEN PUTC
64. L and ESC keys The DEL key erases all of the information that has been entered for the channel that the pointer is currently on The ESC key is used to return to the main menu 31 The channel description screen for the example problem discussed earlier is shown in Figure 4 4 The two transducers to be used at the category C weld detail are connected into channels 1 and 2 The calibration for the transducers is 0 81 MV V output at 7 0 ksi for the first transducer and 0 94 at 7 0 ksi for the second transducer category detail corresponds to a fatigue detail number of 4 and the default values of 16 00 ksi and 1 00 ksi for the maximum and minimum stress ranges will be used For the category detail one transducer and one strain gage will be used and they are connected to channels 4 and 5 The calibration for the transducer is 0 95 MV V at 7 0 ksi and the calibration for the strain gage is 0 35 MV V at 20 0 ksi Category E corresponds to fatigue detail number 7 and again the default values for Sr Max and Sr Min will be used Once the data has been entered as shown in the figure the data should be saved using the F2 key and then sent to the Campbell using the F3 key The channel description data was saved under the filename EXAMPLE 21X After the data has been sent the Campbell is programmed and is ready to take data The ESC key can then be used to return to the main menu 4 3 Data Acquisition The data acquisition menu is a
65. LL UL LL UJ lt LL lt LL lt J lt U LL rm n Land n pn Le C Zzzrczzzrzrzrezrzz See eA O u O cO rn u e m cc rO lt lt lt Q ec wel gt gt 2 gt 22 gt 5 gt 22 uoeo w w w w Ww w O w O w O w O WU u u CONTON O NANN ee ON czzzczzcz r r r rzz Fr OW 2ZZZ2z2Z2ZZ cr zz 2222227222 rererere 2002 lt lt lt lt lt t lt lt u u II reer eee 22222 f mnmdaomtmugg re se OO 115 EI 1 J 22 30222 4022 DEN 2 3 43 2 1 od 22 2 2 3 md 2 eed moan lt lt lt lt lt X X lt lt lt lt lt X lt lt lt lt lt lt lt lt lt lt lt 4 lt lt lt lt lt K lt K lt X lt X lt lt lt lt lt coll
66. MIN A 1 28 ksi 3 ksi B 2 20 2 3 16 1 4 16 1 D 9 14 1 6 9 5 E T 5 For continuous data collection it is not necessary to enter fatigue detail number based on the AASHTO categories Any number from 1 99 may be entered For numbers from 8 99 no values for maximum and minimum stress ranges will ap pear and these stress range limits should be entered as described in steps 5 and 6 9 Sr Max The maximum stress range that is expected during the test on this channel should be input in ksi The default values based on the fatigue detail number may be changed if desired In the rainflow mode stress cycles with ranges up to the maximum stress range plus 596 will be recorded properly Stress cycles exceeding this value will be recorded but will be assigned the value of the maximum plus 5 For continuous data tests the Sr Max value is used for scaling only and does not actually limit the maximum stress that can be recorded The absolute maximum stress values that can be recorded are governed by the maximum voltage range that the Campbell is set to and the calibration of the strain gage or transducer The Campbell voltage range that 15 set automatically by the 21X program is 5 mV for strain gages and 50 mV for transducers This allows a stress of greater than 50 ksi to be recorded when using transducers or strain gages with gage factors of approximately 2 The Campbell voltage range may be increased using the low level progra
67. N RECORD INFO DONE TRUE ENO END ELSE DONE TRUE UNTIL DONE END C N B PROCEDURE MOVE BACK VAR RESPONSE MESSAGE I J K INTEGER CH CHAR BEGIN INIT CAMPBELL COM B PUTC COMCCHRC13 READLNCAUX RESPONS READLNCAUX RESPONS READLNCAUX RESPONS PROCEDURE SET CR21X TIMECCR21X TIME TIME VAR RESPONSE MESSAGE J K INTEGER CH CHAR BEGIN INIT CAMPBELL NSE TO ACCR21X TIME HOUR 21 TIME HOUR 10 EN BEGIN SESCONSEERH CHR 2 D m D c mmm Qro kawa usd 76 WRS COM RESPONSE PUTC COM RESPONSE 1 TO A CR21X TIME MINUTED If CR21X_TIME MINUTE lt 10 THEN RESPONSEI21 m RESPONSEL 1 RESPONSE 0 RESPONSEL1 CHR 2 CR21X TIME SECOND E 1 n f 5 1 CHR 2 WRS COM PUTC COM COM READLNCA READLNCA END 4 TOMO PROCEDURE CR21X TIME VAR RESPONSE MESSAGE K INTEGER CHAR BEGIN INIT CAMPBELL f m lt 92092797 220222 m m m cto c Pm GOO i WDD lt Qooc IX X AA w uf ato w v am 2202020 200 m m 00 DDD 9 maenmoo z z D 9 g c5
68. ND C IOresult O IF FOUND THEN f duplicate file exists BEGIN CROW COL 25 4 File exists Overwrite Y or N DN FALSE WHILE NOT DN DO GETC C KEY can CHRCKEYO IN THEN ON TRUE IF CHRCKEY IN Y y THEN overwite file BEG N RECORD INFO DONE TRUE END END then ELSE BEGIN RECORD INFO DONE TRUE 9 END END ELSE DONE TRUE UNTIL DONE IF 01 lt gt CHR 0 THEN 3 BEGIN FOR 1 TO ORD CFNAMELO12 2 DO TEMP 21 TEMP NAME O CHRCORDCFNAME 01 2 WRCOLCROW COL 12 3 B 3 WRCOL C ROW COL 2 3 TEMP END END 5 HO RUNE SHOW VALUES VA ROW CHANNEL COL INTEGER CAT STRINGIA BEGIN ROW TABLE START ROW 4 FOR CHANNEL 1 TO 8 DO BEGIN CASE CHANNEL_ INFO CHANNEL TRANSDUCER OF 0 WRCOL CHANNEL INFOCCHANNELI TRANSDUCER Undefined t WRCOLCROW CHANNEL INFOLCHANNELI TRANSDUCER COL 3 Strain Gage 2 WRCOLC ROW CHANNEL INFOLCHANNELI TRANSDUCER Transducer END COL CHANNEL INFOLCHANNELI DETAIL COL WRCOLCROW COL 15 3 IF CHANNEL 1 5 CALIB gt 9999 0 THEN WRCOL ROW COL 15 3 F ACCHANNEL 1 5 CALIB
69. NE FALSE FDONE FALSE NEW FALSE FLEN 0 ELEN 0 WHILE NOT DONE DO BEGIN ELEN 0 FALSE WHILE NOT FDONE DO BEGIN GETC CB IF LEGAL CCCB THEN BEGIN WRCOLCROW COL 14 CHR CCB2 COL COL 1 CURSORCROW COL FLEN FLEN 1 NAMEILFLEN 21 1 IF FLEN 8 THEN BEGIN FDONE TRUE NAME FLEN 3 WRCOLCROW COL 14 COL COL 1 CURSORCROW COL END END ELSE 59 gt 0 AND 46 FDONE TRUE 14 COL 1 CURSOR CROW COL NAMECFLEN 3 3 IF CB 8 AND FLEN gt 0 COL 1 Ow COL FLEN IF 29 20 IF SPECIAL CB THEN BEGIN FDONE EDONE mrmr iunt in END ELSE DISP E 2 mmm gt rrr END WH LE NOT EDONE DO BEGIN GETC CB IF LEGAL THEN BEGIN END ELSE WRCOL CROW COL 14 CHRCCB COL COL 1 CURSORCROW COL ELEN ELEN 1 NAME TFLEN 3 ELEN CHR CB iF ELEN 3 THEN BEGIN EDONE TRUE DONE TRUE END IF SPECIALCCB THEN BEGIN EDONE TRUE DONE TRUE IF ELEN 0 THEN BEGIN ELEN 3 NAMETFLEN 4 NAME FLEN 5 NAMEILFLEN 81 END ENO ELSE IF CB 8 THEN ELEN gt 0 THEN BEGIN COL COL WRCOL CURSOR ELEN 1 t W COL 14 w at w gt x gt x 9 w 79 ELSE BEGIN COL COL 2 WRCOL ROW COL 14
70. NT FIELD INTEGER MEANS BINS INTEGER AMPLITUDE BINS INTEGER LOW LIMIT INTEGER HIGH LIMIT INTEGER VALLEY DISTANCE REAL CR_LF STRINGI2 CR CHAR 5 INTEGER 21 CHANNELS INTEGER DSP INTEGER MP TR INTEGER NSCAN INTEGER PLOT_DATA ARRAY 1 81 OF PLOT_ARRAY NPOINTS INTEGER PROCEDURE CLS STROW STCOL ENDROW ENDCOL COLOR BYTE VAR REGS REGISTERS BEGIN WITH REGS DO BEGIN AX 0700 BX COLOR 256 0 CX STROW 256 STCOL DX ENDROW 256 ENDCOL END INTRCSTO REGS END PROCEDURE SCROLL UP STCOL ENDROW ENDCOL BYTE VAR REGS REGISTERS BEGIN WITH REGS DO BEGIN AX 0601 BX 0700 CX STROW 256 STCOL i ie 256 ENDCOL INTR 10 REGS END PROCEDURE SCROLL STROW STCOL ENDROW ENDCOL BYTE VAR REGS REGISTERS BEGIN WITH REGS DO BEGIN 0701 BX 0700 CX STROW 256 STCOL i DX ENDROW 256 ENDCOL END INTRCS 10O REGS END PROCEDURE CURSOR ROW COL BYTE VAR REGS REGISTERS BEGIN WITH REGS DO POS BEGIN AX 0200 BX CURR PAGE X 256 DX ROW 256 COL END INTRC 10 REGS END PROCEDURE SEL PAGE VAR REGS REGISTERS BEGIN REGS 5 256 CURR_PAGE INTR 10 REGS END PROCEDURE GETC VAR KEY BYTE VAR REGS REGISTERS BEGIN REGS AX 0000
71. NTRY cd campbell 21X F5 F2 example return F3 ESC F9 F1 F3 F4 exzero return F1 F5 any key F6 1 2 4 5 return any key F8 exa return F5 any key F6 1 2 4 5 return any key exb return FIGURE 4 6 DESCRIPTION change to campbell directory execute 21X program enter channel description screen enter channel data as shown in Figure 4 4 save channel description data channel description filename send channel description data to Campbell exit to main menu enter data acquisition mode check channels verify that all active channels are reading properly take data for zeroing process send zeroing values to Campbell save zeroing values in file named exzero 21x check channels verify each channel is reading approximately sero begin taking data for first single truck test end single truck test retrieve single truck test data plot single truck test data plot channels 1 2 4 and 5 erase plots from screen save single truck test data save data in file exa stk begin taking data for second single truck test end single truck test retrieve second single truck test data plot second single truck test data plot channels 1 2 4 and 5 save data from second single truck test save data in file exb stk Example Test 41 ENTRY DESCRIPTION F9 begin rainflow test 1440 use rainflow period of 14
72. NUTE 2 RAIN INTERVAL 4 FOR CHANNEL 1 TO 8 DO BEGIN wWwRITELNCDESCRIPTION FI LE CHANNEL INFOLCHANNEL 1 ID 1 WRITELN DESCRIPTION_FILE CHANNEL_INFOI CHANNEL1 TRANSDUCER I 6 WRITELNCDESCRIPTION FILE CHANNEL DETAIL WRITELNCDESCRIPTION FILE CHANNEL 1 EXCITATION WRITELNCDESCRIPTION FILE CHANNEL CHANNEL WRITELN DESCRIPTION_FILE CHANNEL_INFO CHANNEL ROW WRITELN DESCRIPTION_FILE CHANNEL_INFO CHANNEL 1 SR_MAX WRITELN DESCRIPTION_FILE CHANNEL_INFOICHANNEL 1 SR_MIN WRITELNCDESCRIPTION FILE CHANNEL INFOLCHANNEL OFFSET WRITELNCDOESCRIPTION FILE CHANNEL NFOLCHANNEL MULTIPL IER WRITELN DESCRIPTION_FILE CHANNEL_INFO CHANNEL 1 S_CALIB WRITELNCDESCRIPTION FILE CHANNEL INFOLCHANNEL1 MVPERV ND CLOSE DESCRIPTION_FILE WRCOLCROW COL 25 4 1 END record BEGIN DONE FALSE REPEAT IF FNAME O lt gt CHR O THEN BEGIN FOR i 1 TO ORD FNAMELO12 2 DO TEMP FNAME I 2 TEMP NAMEFO CHR ORD FNAME 01 2 END CLSCROW 0 ROW 79 0 WRCOLCROW COL 3 Save File IF FNAME O1 lt gt CHR 0 THEN WRCOLCROW COL 12 4 TEMP NAME CURSOR CROW COL 112 FNAME O CHR O GETNAM IF CFNAME O lt gt CHR OOO file specified THEN BEGIN TOES i 1 RESETCDESCRIPTION FILED CLOSECDESCRIPTION FILE Si FOU
73. O CURRENT _CHANNEL TRANSDUCER ROW COL CASE CHANNEL INFOLCURRENT CHANNELI TRANSDUCER OF O CHANNEL INFOLCURRENT CHANNELI EXCITATION 1 t BEGIN strain gage CHANNEL INFOLC RRENT CHANNEL1 EXCITATION DEFAULT SG EXCITATION CHANNEL INFOL CURRENT CHANNELJ RANGE DEFAULT SG RANGE EXCITATION 2 BEGIN f transducer 3 CHANNEL _INFOECURRENT_CHANNEL EXCITATION DEFAULT DT CHANNEL INFOL CURRENT CHANNEL 7 DEFAULT DT END END case 1 END 2 S CALIB CCHANNEL NFOLCURRENT CHANNEL1 S CAL1B CH CHANNEL INFOL CURRENT CHANNEL DETAIL_COL 15 3 MVPERV CALIBCCHANNEL iNFOLCURRENT CHANNEL MVPERV CALIB CHANNEL CHANNEL INE OT CURRENT CHANNEL DETAIL COL 7 I 4 GET FATIGUE DETAILCCHANNEL OLCURRENT CHANNEL 1 5 CE Le M CUBEEN CHANNEL 6 GET SR MINCCURRENT CHANNEL END f case CASE KEY PRESSED OF RT ARROW BEGIN IF CURRENT FIELD 6 THEN CURRENT FIELD ELSE CURRENT FIELD CURRENT FIELD 1 END L f ARROW BEGIN IF CURRENT_FIELD 1 THEN CURRENT FIELD 6 ELSE CURRENT FIELD CURRENT FIELD 1 END DN ARROW BEGIN IF CURRENT CHANNEL 8 THEN CURRENT CHANNEL 1 ELSE CURRENT CHANNEL CURRENT CHANNEL 1 END ARROW BEGIN IF CURRENT CHANNEL 1 THEN CURRENT CHANNEL B ELSE CURRENT CHANNEL CURRENT CHANNEL 1 EN F 1 BEGIN LOAD FILECFILE COLD SHOW VALUES END
74. RV_CALIB_MESSAGE MVPERV_CALIB gt 9999 0 THEN WRCOLCROW COL HILITE F_TO_ACMVPERV_CAL IB 2 2 ELSE WRCOLCROW COL 2 HILITE CURSOR ROW COL DONE FALSE 9999 0 GETNUMCTEMPREAL 2 2 IF TEMPREAL gt 9998 0 THEN BEGIN MVPERV_CALIB TEMPREAL FALSE parameter change needs to be programmed WRCOL ROW COL 3 IF MVPERV_CALIB gt 9999 0 THEN WRCOLCROW COL 3 F TO ACMVPERV CALIB 2 2 08 ELSE WRCOLCROW COL 2 3 PROCEDURE GET FATIGUE DETAILCVAR CHANNEL CHANNEL RECORDO VA HOW COL INTEGER DONE BOOLEAN i CAT STRINGIA TEMP REAL REAL OLD DETAIL INTEGER BEGIN ROW CHANNEL ROW COL CHANNEL DETAIL_COL WRCOL CMESSAGE_ROW 0 3 DETAIL_MESSAGE OLD DETAIL CHANNEL DETAIL IF CHANNEL DETAIL 0 THEN BEGIN eg E mage ees i ELSE BEGIN WRCOLCROW COL HILITE 3 4 4 1 1_ TO ACCHANNEL DETATILO O 3 IF gt 0 AND CHANNEL DETAIL lt 7 6 5 MAX SRMAXICHANNEL DETAIL 5 MIN SRMINI CHANNEL DETAIL WRCOL CROW COL 12 3 WRCOL CROW COL 12 3 F_TO_AC CHANNEL SR_MAX 2 2 WRCOL CROW COL 20 3 pug oe 9 END CURSORCROW COL 4 TEMP REAL 9999 0 GETNUMCTEMP_REAL 2 0 IF TEMP REAL 0 0 THEN BEGIN CHANNEL DETAIL REAL
75. SCREEN SET TRUE END TRANSLATE CRESPONSE3 K DATA_POINTS PROTI DUE RETRIEVE_SINGLE_TRUCK VA CHANNEL INTEGER DATA_POINTS VAL_ARRAY COUNTER INTEGER SCAN INTEGER BEGIN WRCOLCACT VITY MESS ROW 5 3 Please wait COUNTER NSCAN JUMP TO MPTR IF NSCAN MAX PLOT POINTS XXXXEXXXXX THEN NSCAN POINTS xx ACQ_SCREEN WRCOLCACTIVITY _MESS_ROW 5 3 Please wait HIGHWAYS AND PUBLIC TRANSPORTATION w 4 Vt 8 vo wt Retrieving X XX Retrieving truck data truck data 6 gt 1 NSCAN DO GI WRCOL CACTIVITY MESS ROW 60 3 reading scan WRCOLCACTIVITY MESS ROW 75 3 i WRCOLCACTIVITY_MESS_ROW 75 3 1_TO_ACCOUNTER COUNTER COUNTER 1 DUMP_SINGLECDATA_POINTS FOR I 1 TO CR21X CHANNELS DO BEGIN J ACTIVE CHANNELS 11 PLOT_DATALJ SCAN DATA POINTS 11 VAL END CLSCACTIVITY MESS MESS ROW 79 0 END retrieve single truck PROCEDURE SAVE SINGLE TRUCK VAR DONE DN FOUND BOOLEAN STRING 50 1 J K SCAN CH CHAR PROCEDURE RECORD INFO VAR CHANNEL INTEGER DATA POINTS VAL ARRAY COUNTER INTEGER BEGIN wait Saving file to disk RHEWRITECTRUCK DATA WRITELN CTRUCK DATA NSCAN 5 1 FOR 1 CR21X CHANNELS DO
76. SCREEN SET TRUE END f X X A m m s x a c m s ee s PROCEDURE UPDATE SCREEN SR VAR I INTEGER BEGIN FOR 1 TO 8 DO BEGIN CCCHANNEL iNFOL 11 DETAIL lt 7 AND CHANNEL INFOL11 DETAIL gt 0 THEN BEGIN CHANNEL_INFOCI SR_MAX SRMAXICHANNEL INFOL 1 DETAIL ao ANNER INFOLIJ SR MIN SRMIN CHANNEL_INFOLII 1 END SHOW VALUES END PROCEDURE GET TRANSDUCERCVAR TRANSDUCER INTEGER ROW COL INTEGER AR DONE BOOLEAN BEGIN WRCOLCMESSAGE ROW 0 3 TRANS MESSAGE CASE TRANSDUCER OF WRCOL ROW COL HILITE Undefined 9 1 WRCOLCROW COL HILiITE Strain Gage 2 WRCOLCROW COL HILITE Transducer END case CURSORCROW COL 84 GETC KEY IF CHRCKEYO g G t T THEN BEGIN IF CCHRCKEY G x OR CCHRCKEYO 4 THEN TRANSDUCER z 1 ELSE TRANSDUCER 2 DONE TRUE uo PROGRAMMED FALSE f parameter change needs to be programmed Bs ELSE IF SPECIALCKEY THEN DONE TRUE D CASE TRANSDUCER OF 0 WRCOLCROW COL 3 Undefined i 1 WRCOLCROW COL 3 Strain Gage 2 WRCOLCROW COL 3 Transdu
77. T 1 0 DO BEGIN TEMP 1 TEMP1 10 0 WLEN WLEN 1 END TEMP 1 VLU VLU FOR J 1 TO WLEN DO BEGIN FACTOR 1 0 WHILE K WLEN DO BEGIN FACTOR FACTOR 10 0 K 1 END TEMP1 TEMP2 FACTOR ALPHA J CHRCTRUNCCTEMP1 48 TEMP2 TEMP2 FACTOR TRUNCCTEMP1 END 0 THEN BEGIN FOR J 1 TO WL DO BEGIN WLEN 1 ALPHAIWLEN 2 Q END END ALPHAIWLEN 1 FOR 1 TO FLEN DO BEGIN TEMP2 TEMP2 10 0 ALPHAIWLEN 1 11 CHRCTRUNCCTEMP2 48 i z TEMP2 TRUNCCTEMP2 EN i ALPHAI 0 CHR CWLEN 1 FLEN IF SIGN 1 THEN BEGIN FOR 1 WLEN 1 FLEN DOWNTO 1 DO ALPHALI 1 ALPHA 11 ALPHA 0 CHROWLEN 1 FLEN 1 END IF SIGN 1 THEN 2 ELSE 1 1 x L9 WHILE CCALPHA L 072 1 1 0909 DO 1 1 IF SIGN 1 THEN J 2 ELSE J 1 FOR K J TO DO 5 ALPHAILK J ALPHA CHRCORDCALPHAIO J 6 Ivo epos WHILE ALPHATI gt DO l 5 l 1 J 1 FOR 1 TO J ALPHA2 1 5 FOR 1 TO OROCALPHA 0 DO ALPHA2 1 J 1 1 ALPHA2 01 CHRCORD CALPHA 0O J 34 F_TO_A ALPHA2 ENO 4 FUNCTION TO ACIVLU INTEGER MESSAGE
78. TECHNICAL REPORT STANDARD TITLE PAGE 3 Recipient s Catalog No 1 Report No 2 Government Accession No FHWA TX 464 1F 4 Title and Subtitle 5 Report Date March 1988 6 Performing Organization Code ESTIMATING RESIDUAL FATIGUE LIFE OF BRIDGES 7 Author s G Jeff Post Karl H Frank and Bahram Alec Tahmassebi 9 Performing Organization Name ond Address B Performing Organization Report No Research Report 464 1F 10 Work Unit No Center for Transportation Research Ihe University of Texas at Austin Austin Texas 78712 1075 11 Contract or Grant Research Study 3 5 86 464 13 Type of Report ond Period Covered 12 Sponsoring Agency Name ond Address Texas State Department of Highways and Public Transportation Transportation Planning Division P 0 Box 5051 Austin Texas 78763 5051 15 Supplementary Notes Study conducted in cooperation with the U S Department of Transportation Federal Highway Administration Research Study Title Estimating Residual Fatigue Life of Bridges 16 Abstract Final 14 Sponsoring Agency Code This manual describes the capabilities and operating procedures for an automated bridge testing system The system was developed for the Texas State Department of Highways and Public Transportation to provide a portable self contained and user friendly means for evaluating the residual fatigue
79. X Box The Campbell 21X Micrologger is mounted in an aluminum box which provides protection for the 21X during deployment The box also provides connectors which greatly simplify the field hook up of transducers strain gages and batteries to the Campbell The box is constructed of 3 16 1n thickness aluminum and 4 has outside dimensions of 25 x 10 x 11 in and is shown in Figure 2 1 The top of the box is bolted on and is oversized to provide for ventilation The left side of the box has eight connectors corresponding to the eight input channels of the Campbell Figure 2 2 shows the channel number corresponding to each connector The right side of the box is equipped with two battery connectors and a con nector for the Data General computer The arrangement of these connectors is shown in Figure 2 3 voltmeter is also provided to indicate the voltage level of the battery s con nected to the Campbell The small button to the left of the voltmeter is used to activate the meter The small light below the voltmeter indicates whether or not the Campbell is currently taking data the light flashes when the button next to it is pushed then the Campbell is taking data Also included in the Campbell box is a small black communication box which is required to establish communication between the Campbell and the DG computer schematic of the wiring arrangement in the Campbell box is shown in Figure 2 4 The specifications and complete opera
80. XZERO Rainflow Description File EXRFL Single Truck Tests Data Files 1 STK 2 EXB STK 3 STK 4 STK Rainflow Test Notes Notes Notes Notes Rainflow Period 1440 minufes Start Date 1 20 88 1 Time 14 20 Stop Date 12488 Time 9 55 Data File EXRFL RFL trans 1 1 trans 3 2 trans 4 4 S G 5 ful Y k in FIGURE 4 2 Example Test Data Sheet Channel no Type Undefined Undefined Undefined Undefined Undefined 3 RM Undefined NAM Message Line Undefined Undefined Undefined 1 2 4 5 7 9 2 C T gt D F1 Load File F2 Save File F3 Send File Del Erase Channel ESC Exit FIGURE 4 3 Channel Description Input Screen 16 28 column which corresponds to the stress level entered in the first column linear relationship between the stress level and the strain gage output is assumed and the MV V value represents the voltage output of the gage in millivolts divided by the excitation voltage for the selected stress level For a strain gage the Campbell is programed to use an excitation voltage of 4 volts and the MV V value can be calculated using the following formula MV V S G F 004 E where S calibration stress level in ksi G F gage factor for strain gage E modulus of elasticity in ksi The value should be entered with t
81. Zero The Data 34 4 3 5 F5 Capture 35 4 3 6 F6 Retrieve Truck 35 4 3 7 Plot Truck Data 35 4 3 8 Save Truck Data 36 4 3 9 F9 Start Rainflow Routine 2 36 4 3 10 F10 Retrieve Rainflow 37 4 4 Low Level Programming 38 2 9 example Test s 2 y DR W Q 39 CHAPTER FIVE ESTIMATION OF REMAINING FATIGUE LIFE 43 Dil Background 8 xx AUN IUE ds 43 5 2 Program RPCO 252 amp oe domom J ues Q 44 5 2 1 Using Program RELO Z v S lt 45 5 3 Calculating Fatigue Life 48 5 3 1 Fatigue Life Calculation 48 APPENDIX DATA GENERAL PROGRAM LISTING 57 2 1 2 2 2 3 2 4 2 5 2 6 2 7 2 8 3 1 3 2 3 3 4 4 2 4 3 4 4 4 5 4 6 9 1 9 2 9 3 9 4 9 9 9 6 9 7 5 8 5 9 9 10 5 11 5 12 5 13 1 LIST OF FIGURES Page Campbell 21 BOX 5 25 d 5 Campbell Box Connector 6 Right Side of Campbell 7 Campbell Box Wiring Diagram 8 Battery 2 2 lt x x Qe 5 5 GIS Qp
82. c c o ww c c 4 0 ou ooo O oc gc oc uuu c co ca c o jz 2 zzz 0 9 gt lt gt z 2 oo gt eq o 1I I a QO 2 c ct cu 4 gt xt xt ii a ow C w ae ou Q gt m p o mMm 0 0 0 zZ 2 uuna e lt e e e lt O O 2 cro lt To lt Z wo Z eee a a gt gt emn ad z Z 5 zz zzo zo OO O co c tr cazzo q Io0m mowowo il 1 1 j gt ona qv oo 203 an Ou o awn lt oo nna lo uu src ww x gt 2 gt 2 lt gt z o lw e ri tho n gt gt gt gt gt gt gt gt lt 0 OH KU lt lt lt K x w we ul gt gt gt gt gt 0 gt gt gt gt z eo m 2 2 2 2 Oe WR LU OWE x uj 0 lt cogodgoOoagauoozuoo uooouoozu z I lt
83. ccessed from the main menu using the F9 key and is shown in Figure 4 5 The main functions that are controlled from this menu include checking the data being received from the individual channels zeroing the channels initiating the collection of single truck continuous mode and rainflow data and retrieving single truck or rainflow data from the Campbell To use the functions on this menu the Campbell must have already been programmed previously i e the channel description sent to the Campbell The specific tasks carried out by each of the function keys are discussed below 4 3 1 F1 Check Channels This function and F2 are used to check that each of the active input channels are giving reasonable readings When the F1 key is pushed the Campbell is instructed to take data for a few seconds After the data has been taken the DG then automatically retrieves the data from the Campbell and processes it The scan number shown at the bottom of the screen indicates the number of readings for each channel that are still to be processed After processing has been completed the high low and average readings in MV V are displayed for each of the channels which were specified on the channel description screen If the Campbell has not been previously zeroed see F3 and F4 then the data displayed will be raw data read directly from the strain gages or transducers If the Campbell has previously been zeroed then the data displayed Calibration S MV
84. cer END f case 1 END PROCEDURE GET SR MAXCCHANNEL INTEGER VAR TEMPREAL REAL DONE BOOLEAN ROW COL INTEGER BEGIN ROW CHANNEL_INFO LCHANNEL ROW COL CHANNEL INFOLCHANNEL DETAIL COL 12 WRCOL MESSAGE 0 3 SR MAX MESSAGE IF CHANNEL_INFO CHANNEL 1 SR_MAX gt 0 0 THEN WRCOL ROW COL HILITE F_TO_AC CHANNEL_INFO CHANNEL SR_MAX 2 2 ELSE WRCOLCROW COc 2 HILITE CURSORCROW COL DONE FALSE TEMPREAL 9999 0 GETNUMCTEMPREAL 2 2 IF TEMPREAL 0 0 THEN BEGIN CHANNEL INFOL CHANNEL SR MAX TEMPREAL IF C CCHANNEL_ INFOC CHANNEL DETAIL lt 7 AND CCHANNEL I NFOLCHANNELJ DETAIL gt 0 THEN BEGIN 6 NFOLCHANNELJ DETAIL CHANNEL INFOLCHANNELJI SR MAX dod SCREEN SR END FALSE parameter change needs to be programmed WRCOLCROW COL 3 IF CHANNEL _ 1 SNAM 0 0 THEN WRCOL ROW COL 3 ACCHANNEL 5 MAX 2 2 ELSE WRCOLCROW COL 2 da 21 3 END 65 PROCEDURE SR MINCCHANNEL INTEGER REAL DONE BOOLEAN ROW COL INTEGER BEGIN ROW CHANNEL INFO CHANNEL R
85. cll ce cell ool ell 8 el ell OR Kiki ol el i i P i i i i PFP FPE 1 FOR CHANNEL CHANNEL 1 5 MIN 141 0 f undefined CHANNEL INFOL CHANNEL1 ZERO 0 0 4 CHANNEL 1 CURRENT 0 0 CHANNEL 1 5 CALIB 9999 9 CHANNEL MVPERV_CALIB 9999 9 CHANNEL 1 1 0 CHANNEL INFO CHANNEL OFFSET 0 0 I ND START TIME HOUR 99 3 START TIME MINUTE 99 RAIN_INIFRVAL 9999 MEANS BINS 2 AMPLITUDE BINS 50 I LOW LIMIT 50 i HIGH LIMIT 50 i PEAK VALLEY DISTANCE 0 2 f 0 2 mv 1 52 ksi RAIN INTERVAL 1440 PROGRAMMED FALSE END m ewe wo a Q w lt w ss cvm mm Uum x ms ds UR im m m x AD Q d m Cub ss cum GED um cam q GER cum GAS dep cem x s m ss Q ELIMINATECCHANNEL INTEGER CHANNEL TRANSDUCER 0 f undefined 2 CHANNEL INFOLCHANNEL DETAIL 0 f undefined 3 CHANNEL_ INFO CHANNEL SR_MAX z 1 0 f undefined CHANNEL _INFOUC CHANNEL SR MIN 1 0 f undefined CHANNEL INFOL CHANNEL1 S CALIB 9999 9 undefined CHANNEL NFOL CHANNEL MVPERV CALIB 9999 9 undefined SHOW VALUES END 1 me cup puc mme Cus MES lama MD Ce
86. e T 0ON C w LL u aH I c cao cc Programmi n Description Level nne a Acquisition Menu to DOS it S STATE DEPARTMENT OF HIGHWAYS AND PUBLIC TRANSPORTATION Load File r r L is e e x C n n Channel j2 gt ya 5 ea Hon H H J 59 fe of ead wader gt gt zz lz uwaoag oume 2o oao BAUD PARITY NSTOP NDATA COM PAR TO 80 DO C M 1 gt 2 TO 66 DO FOR COL BEGIN e Lu am D 9 lt O 2 I c oe Oc Z gt er e gt o gt zo D T n w w b w oo on c gt a 6 92 92 u 2 ul e wU gt o2 2o O lt do wu lt o lt QO oro d g n gw u pe u 2 z c Z Z lt lt lt lt e o o JZ x lt OO gt gt Oat x ON zusausul gt 2 lt 22 22222 lt lt O lt Z lt Z lt Z lt Z G gt am so e TA vf ae P TP AP am om PP om F or ap P
87. e life based on the effective stress range cycles are shown Load Comma Separated Files from RFLO Starting at Cell A20 Fatigue Detail Sr 2x109 cycles 5 8ksi enter value 3 9022 8 Interval Cycles 1 617 3 134 1 567 1 328 3 398 3 339 3 575 l 17 958 gt Cycles Year 936 381 Sr 1 58 1 64 1 58 1 78 1 72 1 71 1 70 1 68 Sr 3 79 5 68 3 79 4 11 4 55 3 79 3 79 5 68 Fatigue Life Analysis Life Yrs 167 6 7 8 171 6 143 6 62 0 64 5 61 3 88 0 Graphs 1 Sr Histogram All Interval 2 Sr Histogram Ea Interval 3 Cycles per Interval 4 Fatigue Damage Factor FIGURE 5 7 Spreadsheet Output The values for all the intervals taken together is also shown The overall values should be used for the fatigue life calculation The estimated fatigue life based on the traffic conditions during the study is 88 years Since the structure is 35 years old one estimate of the remaining fatigue life is 43 years 52 The calculated remains life of 43 years assumes that past and future traffic volume and distribution of trucks within the traffic remain stationary more realistic estimate of the fatigue life can be made by using actual historical traffic counts on the roadway As an example of the use of measured traffic counts assume the following traffic data is available YEAR ADT 1953 5 000 bridge opening 1960 7 900 1970 10 000 1975 15 000
88. e so low that no fatigue damage is occurring at the location The stress ranges listed in Tables 10 31A and 10 31B of the AASHTO Specification for over two million cycles represent the estimated fatigue limit or threshold stress range of each fatigue category The values listed in Table 10 31 for redundant members are based on laboratory studies The values in 10 31B are reduced stress ranges to provide increased reliability for non redundant members If the largest measured stress range gathered in the field study is less than the values listed for over two million cycles for the detail instrumented no fatigue damage occurred at the detail during the period the data was collected If the largest measured stress range is less than or equal to 75 of the threshold value and the data gathering period is representative of typical traffic at least five days of data then it is reasonable to assume that the location instrumented on the bridge will not exhibit fatigue cracking No fatigue life estimate is required since the fatigue life is infinity The 75 limit on the threshold stress range suggested above is based on the authors judgement Higher cutoffs but less than or equal to 100 of the threshold can be justified if the user is satisfied that present or future loadings will not cause an increase in the measured stresses longer sampling period for example two weeks versus one or sampling another week will allow more refined analysis and justify
89. easy to use computer based system to measure the fatigue stresses on a highway bridge The equipment is light weight protected from the elements and powered by ordinary rechargeable storage batteries The equipment is housed in weather proof aluminum boxes which mount directly to the bridge using ordinary C clamps The equipment is designed to stay in place on the bridge unattended during the data collection period A portable lap top type computer is used to program the data collection hardware and to retrieve the data in the field The process is menu driven using software developed in the project The system may also be used to capture the live load stress history of a single vehicle This was done during the field testing of the unit to measure the stresses produced by a large special permit vehicle The resulting stress time history of up to eight measurement point on the bridge can be viewed within minutes after the passage of the vehicle The fatigue analysis procedures use rainflow counting to determine the effective constant amplitude stress range on the bridge The fatigue life assessment uses the stress range cycle relationships of the standard AASHTO fatigue detail categories Software to preform remaining life calculations was developed and sample calculations presented The equipment can use both clamp on type strain gage transducers and single strain gages bonded to the bridge element to measure the stresses in the bridge Calibra tion
90. eet of cable in various lengths has been provided to connect the instrumentation to the Campbell The cable is manufactured by Belden and is insulated with teflon and has a silicon jacket All of the cable is 4 wire except for the strain gage completion boxes which use 3 wire cable to connect to the strain gages The connectors are standard Amphenol connectors The transducers strain gages and DG computer use 5 pin connectors and the 12 volt batteries use 2 pin connectors All of the connectors are sealed to prevent shorting due to moisture 2 2 7 Transducer Calibration Specimen The calibration specimen has been fabricated to fit in a standard tensile testing machine and can be used to calibrate the strain transducers The specimen is shown in Figure 2 8 and is made of 375 inch thick A514 steel 100 ksi yield strength The total length is 37 inches and holes have been drilled on the neck of the specimen for bolting on the transducers The width of the neck is 2 inches and the cross sectional area is 75 in Strain gages have been mounted on both sides of the specimen and these can be used to measure the applied stress if desired The strain gages have a resistance of 120 ohms 15 and have a gage factor of 2 04 The procedures required for using the specimen to calibrate the transducers are given in Section 3 2 12 Fig 2 8 Transducer Calibration Specimen 1 4 dia typ CHAPTER THREE TEST PREPARATION Prior to conducting a br
91. eport No 464 1F Research Project 3 5 86 464 Estimating Residual Fatigue Life of Bridges Conducted for lexas State Department of Highways and Public Transportation In Cooperation with the U S Department of Transportation Federal Highway Administration by CENTER FOR TRANSPORTATION RESEARCH BUREAU OF ENGINEERING RESEARCH THE UNIVERSITY OF TEXAS AT AUSTIN March 1988 The contents of this report reflect the views of the authors who are responsible for the facts and the accuracy of the data presented herein The contents do not necessarily reflect the official views or policies of the Federal Highway Administration This report does not constitute a standard specification or regulation There was no invention or discovery conceived or first actually reduced to practice in the course of or under this contract including any art method process machine manufacture design or composition of matter or any new and useful improvement thereof or any variety of plant which is or may be patentable under the patent laws of the United States of America or any foreign country 11 PREFACE Often when widening an existing highway or rehabilitating an older roadway the bridge superstructure does not satisfy the existing AASHTO fatigue design requirements The superstructure often shows no signs of distress The decision is often made to replace the existing bridge due to its fatigue insufficiency more rational procedure to judge
92. er and offset which are derived from the zero values for each channel The multiplier and offset values act on the raw data to give the zeroed values desired Before reprogramming the DG will ask for a filename to use for saving the de scription file This description file will contain the data entered into the channel description screen the zero readings and the multiplier and offset values used This information must be saved since it is used to retrieve and process the data The filename should be different than the filename used to save the channel description data The channel description data 35 file contains default multiplier and offset values of 1 and 0 This channel description data fle may be used again for another test at a later time but the description file containing the actual zero multiplier and offset values should not be reused No filename extension should be given the DG will assign an extension of 21X This is the same extension that is assigned for the channel description filename so care should be taken not to write over the channel description file In the example problem the channel description data file was named EXAMPLE 21X The description file containing the zero values will be named EXZERO 21X 4 3 5 F5 Capture Truck The F5 through F8 functions are used for capturing a single truck crossing a bridge The F5 function instructs the Campbell to start taking data continuously until instructed to stop The Cam
93. eriods number of channels 100 3 If the total length of time for which data is going to be taken exceeds 18 days then the battery life needs to be considered See section 3 3 When taking continuous data single truck test the maximum length of the test depends on the rate at which data is being taken A maximum of 660 scans can be taken for any given single truck test One scan consists of one reading of each active channel The maximum test length is then equal to the scan rate times 660 The scan rate is automatically set to 0125 seconds by the Data General This is the fastest possible scan rate that the Campbell can use With the 0125 second scan rate the maximum length of a single truck test would be approximately 8 25 seconds If several channels are being used the Campbell may not be able to actually scan each of the channels every 0125 seconds and the maximum test time may actually be longer If longer test lengths are desired then the scan rate must be increased If a test length of 90 seconds is desired then the scan rate must be set to 136 seconds or greater The procedure for adjusting the scan rate is discussed in Appendix B Instrumentation Spacing All of the locations that are to be instrumented must be connected by cable to the Campbell box The maximum spacing between the instrumentation is therefore limited by the length of available cable Four 90 foot cables and twelve 50 foot cables have been provided The
94. ervals The DG will then begin to retrieve the rainflow data from the Campbell The total number of intervals being retrieved will be displayed along with the interval number of the current interval being retrieved The intervals are retrieved one at a time and are then automatically saved on the DG hard disk before the next interval is retrieved The data is saved in a file that has the same filename as the channel description file used in F9 and F10 However the file extension will be RFL instead of 21X If a rainflow channel description file of EXRFL is used then the rainflow data will be stored in EXRFL RFL The number of intervals retrieved will not include any partial intervals at the beginning and end of the test period For example if a test begins at 10 00 a m on Monday and ends at 4 00 p m on Friday and has a rainflow period of 1440 minutes 1 day only three intervals will be retrieved These will be for Tuesday Wednesday and Thursday The data taken on Monday and Friday will be only partial intervals and will not be recorded Retrieving rainflow data takes approximately 45 seconds per interval per channel 4 4 Low Level Programming Mode The low level programming mode allows the user to program the Campbell di rectly through the DG In this mode the DG acts only as a communication link to the Campbell and the Campbell programming is done just as it would be done directly on the Campbell keyboard This feature has been i
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96. evel The following procedure should be used to obtain the transducer calibration data The calibration bar should be mounted in a test machine which is tall enough to handle the 37 long bar with a tension capacity of at least 10 kips The load indicator on the test machine should be zeroed after clamping down the calibration bar One transducer can then be bolted to the specimen and connected to channel 1 of the Campbell box 12V battery should also be connected to the box to provide power for the Campbell The Campbell must then be programmed to read data from the transducer For the calibration test it is best to program the Campbell directly using the Campbell keyboard as opposed to using the DG for programming The keystrokes required for the program are shown in Figure 3 2 After the battery is connected to the Campbell the Campbell will come on check the memory circuits and then display 11 1111 11 on the screen After the eight ones are displayed programming can begin Each entry in the program should be followed by an to advance to the next program step If a mistakeis made in a program entry the key can be used to backup and the previous entry can be corrected Alternatively the 5 6A 1A 13 1 1 4000 1 1 0 6A 17 FUNCTION enter programming Table 1 execution interval 0 5 seconds Instruction 6 full bridge measurements 1 strain transducer being
97. f compile program and execute CLS3CMESSAGE ROW 0 MESSAGE ROW 79 0 PROGRAMMED TRUE DURE WAITCLENGTH INTEGER R START CURRENT TIME 5 DONE BOOLEAN CH CHAR LAPS RESPONSE 1 MESSAGE BEGIN DONE FALSE WITH REGS DO BEGIN AX 2C00 MSDOSCREGS START MINUTE START SECOND END WHILE NOT DONE DO BEGIN WiTH REGS DO BEG uu X DX 0 CURRENT SECOND CSTART MINUTE 60 START SECOND 4 MN em m CCUR zZ AZOO 2 1 mm AUX RESPONSE 1 rD 12 gt PROCEDURE LOAD_STK C ROW COL INTEGER VAR DONE BOOLEAN TEMP_NAME STRIN CHANNEL INTEGER J SCAN IN CH CHAR BEGIN G 50 TEGER ASSIGN STK_FILE C TR2 STK 5 1Oresult 0 DONE 25 4 File Not Found L EGIN t RE 5 IF ELSE 8 A Reading Data 3 NSCAN S 68 J ACTIVE CHANNELS READCSTK FILE PLOT DATAL J SCANIO END READLNCSTK FILE END END f else 1 I CLOSECSTK_FILE ENO 4 PROCEDURE PLOT CHANNELCN CHAN NPOINTS INTEGER PCHAN PLOT CHANNELS VAR d INTEGER XMAX XMIN INTEGER XLEN YLEN REAL XSCALE YSCALE REAL X1 X2 Y1 Y2 INT
98. ffic fluctuations more refined analysis is obtained if the number of days of collection is increased Based on our experience however care should be exercised in extending the testing for periods more than one week Daily variations in traffic can be considerable If for example eight days of data are collected and the repeated day of the week is a low traffic day the resulting fatigue life estimate will be biased and possibly unconservative Before a fatigue life is estimated the collected data should be screened to de termine if it looks reasonable The effective stress range for each collection interval of a channel should be reasonably constant This daily effective stress range is given in the printout from RFLO The number of cycles for each interval for all the channels should show reasonable correlation That is the ratio of the number of cycles between two chan nels from one day to another should be reasonably constant If large differences occur that cannot be explained then the field test should be repeated to determine the cause of the differences Switching transducer is suggested to determine if the differences are caused by a faulty transducer 5 3 1 Fatigue Life Calculation Example The data from a seven day one interval equal to a day test of an AASHTO category E fatigue detail are used to estimate the fatigue life of a bridge The data was analyzed using a commercial spreadsheet program SuperCalc 4 A copy of the Su
99. g input is required for each channel to be used 1 Channel No The channel number corresponds to the input channel being used on the Campbell The connectors for each Campbell channel are numbered on the outside of the Campbell box If the cable from a strain gage or transducer is connected to the number 2 connector on the Campbell box then the data for that gage or transducer should be entered into the channel number 2 line on the screen 2 Channel Type In this space a G should be entered if a strain gage is being used on this channel and a T should be entered if a transducer is being used This information is used to set the expected input voltage range for the channel 3 Calibration This column is used to input the specific calibration data for the strain gage or transducer being used on this channel Two related inputs are required stress level in ksi is entered in the 5 column The stress level can be chosen up to a value of 99 99 A MV V value is then entered in the adjacent 26 BRIDGE TEST DATA SHEET Bridge Location Bridge Test Test Dates Start 1 20 88 Finish 1 28 88 Instrumentation Description Fatigue 1 field splice girder 4 2 span cover plate girder 4 north side 1 st support Description Files C E Instrument Channel TOT Descript 4 N Channel Description File _EXAMPLE Zero Description File _E
100. hmassebi and a listing of the program code is included in Appendix D The 21X program and others used for conducting bridge tests are stored on the DG hard disk in the CAMPBELL sub directory The program can be executed simply by typing 21X while in the CAMPBELL directory The 21X program is menu driven and upon entering the program the main menu is displayed The main menu is shown in Figure 4 1 From this menu three options can be selected using the function keys at the top of the DG keyboard or the program can be exited by pressing ESC Pressing the F3 key enters the low level programming mode for the Campbell This can be used to check the current program in the Campbell to change the scanning rate to modify the Campbell program or to input a completely new program It will not be necessary to use this mode for most tests The F5 key brings up the channel description screen which is used to input the number and configuration of strain gages and transducers Inputting the channel description data will normally be the first step in conducting a test The F9 key accesses the data acquisition menu which is used to take and retrieve data Each of these three secondary menus will be discussed further in the following sections To return to the main menu from any of the 23 TEXAS STATE DEPARTMENT OF HIGHWAYS PUBLIC TRANSPORTATION F3 Low Level Programming F5 Channel Description F9 Data Acquisition Menu ESC Exit to DOS Fig 4 1
101. idge fatigue test proper preparation is required to help insure that quality data is obtained The major tasks involved in test preparation are the development of a test plan calibration of the strain transducers assembling and setting up the required equipment and arranging for access to the bridge 3 1 Test Plan The initial step required in preparing for a bridge test is to clearly define a test plan The test plan should identify the locations to be instrumented the fatigue category of each location the type and number of instruments strain gages or transducers at each location the length of the test and whether continuous or rainflow data is to be taken test plan must be developed which is within the limitations of the data acquisition system and which gives a clear picture of the fatigue condition of the bridge Figure 3 1 is a data sheet which can be used in putting together a test plan The data acquisition system has been developed to be as flexible as possible but the following limitations must be considered when developing the test plan Number of Data Channels The maximum number of channels of data that can be taken at one time is eight combination of strain gages and transducers can be used Maximum Test Length The maximum test length depends on whether continuous or rainflow data is taken and is controlled by the memory capacity of the equipment When taking rainflow data the maximum test length de
102. ld studies can be performed to redefine the number of stress cycles and effective stress range produced by traffic to compare with the values estimated in this analysis Influence of Cycles Day From Field Test R 0 51 Estimated ADT Capcity 50 000 nana e e im nOTTn O I F e A eta 140 120 x 100 Fatigue Life Estimate Years 80 n M qe 2 1500 1800 2500 2800 3300 3800 Stress Cycles per Day From Field Test Figure 5 12 Influence of ADT Capacity on Fatigue Life R 0 51 Cycles Doy Field Test 2565 2 IX MM I DNE i Fatigue Life Estimate Years i t i fe eee eee 30000 60000 90000 120000 Estimated ADT Capacity Figure 5 13 APPENDIX DATA GENERAL PROGRAM LISTING PROGRAM CR21XCINPUT OUTPUT 1 t AUTHOR BAHRAM ALEC TAHMASSEB DFVELOPED FERGUSON STRUCTURAL ENGINEERING LABORATORY l BALCONES RESEARCH CENTER i UNIVERSITY OF TEXAS AT AUSTIN VERSION 1 1 7 1 88 GER m asa es Be e ree CONST 1 59 2 60 F3 61 F4 62 F5 63 F6 64 7 65 F8 66 4 9 67 F10 68 ARROW 72 DN_ARROW 80 LT_ARROW 75 RT ARROW 77 t CARRIAGE
103. lt x 2 o oq Ou 22 gt 7 gt z wm aqu lt z 0 m o gt Z O0 m a ec r 3 Z Lr a 5 n a o ul e u z c re o o o e OES o az 2 gt a F a m e 2 gt T m gt gt gt Z 2 v lt lt ZO e gt gt O Wr lt oz o 2e m Z lt 2 Q a X eco lt 1 za lu eo lt lt In _ ovoo On t x v a so na a a sn e gt ve e lt P Od lt O u 2 Zz wee 5 1 22 05 Z mAd wv gt lt lt v lu lt si z gt Z O uo o 4 O gt e gt lt lt 2 2 5 2 M JO wu HOU FM I dE Nx gt lt lt Y Nod Wa AJ 3 o O I O gt 2 gt lt gt lt zzzrz zzzo 1 lt CeO COW m re z gt gt OOOOOcC X oOc lt zourm o q ro rc AQ 2 or l l la AN A gt z ju I OU Q zzoz ao Or de W WNN 2S OX Za gt z ws 007000 0 OO ooucd
104. mming mode if higher voltage ranges are required 6 Sr Min In the rainflow mode it is necessary to enter a minimum stress cycle value that is to be recorded This is to prevent the recording of low level cycles that are the result of electronic noise or are of no structural significance A value of 0 5 ksi is generally sufficiently low to prevent recording of noise cycles The default 30 values that entered based the fatigue detail number used are based on the best judgement of the authors as stress ranges which would produce insignificant fatigue damage For continuous data tests the Sr Min value has no effect on the test and any value may be entered The above information can be input in any order and as the cursor is moved from column to column a message is displayed near the bottom of the screen which gives helpful information about the data to be input in that particular column Below the message line is displayed the function keys which can be used from the channel description screen The F1 and F2 keys can be used to load and save channel description files These functions are useful because they allow the channel input data to be input prior to going into the field The F1 key can be used to load a previously saved file into the channel description screen When the F1 key is pressed a prompt will be given requesting the filename of the file to be loaded When the F2 key is pressed to save the channel data promp
105. ncluded to make the system as flexible as pos sible but for most applications it will not be necessary to use this mode The 21X program has been developed to program the Campbell automatically for typical tests n example of a standard Campbell program generated by the 21X program is included in Appendix A If some changes to the standard Campbell program are desired they can be made using the low level programming mode n example of this might be to change the sampling rate being used by the Campbell The 21X program automatically sets the sample rate at the fastest possible 0 0125 seconds For a single truck test it might be useful to use a slower sample rate The sample rate can be adjusted using the low level programming mode n example showing the keystrokes necessary to change the scan rate are given in Appendix B To use this mode it is necessary to understand the Campbell programming pro cedures These are discussed extensively in the Campbell manual Additional commands 39 that are used by the DG in the low level programming mode are discussed in Appendix B When this mode is entered there are no prompts or menus provided To exit to the main menu press the ESC key 4 5 Example Test To illustrate the steps required in a typical test the computer entries required to execute the example test discussed in the previous sections are shown in Figure 4 6 The final Campbell program generated is shown in Appendix A 40 E
106. nual When F9 is pressed the DG will ask for a rainflow period The rainflow period is the length of time over which the Campbell takes rainflow data before writing the rainflow histogram to final storage If a period of 20 minutes is specified the Campbell will take rainflow data for 20 minutes then write the histogram to storage and start taking data in a new histogram for the next 20 minute period The maximum period that can be used is one day 1440 minutes When entering the rainflow period the period must be in whole minutes a decimal point should not be entered The DG will then ask for the current time The time must be entered in military format ie 4 30 am 0430 and 4 30 pm 1630 The two digit hour should be entered first followed by the two digit minute The DG then asks for a filename for storing the channel description data This file can have any name but just as in the F4 function the filename should be different from the file used for the channel description data Again a file extension of 21X is automatically assigned to the filename After the file is saved the DG will program the Campbell for taking rainflow data and will set the rainflow capture flag The Campbell will then begin to take rainflow data Sometimes when the rainflow capture flag is being set the DG keyboard will lock up This is due to a bug in the Campbell processing unit which occurs occasionally when a very short rainflow period is used If this occu
107. ogram will not know how many histograms are to be retrieved For these reasons only time intervals which divide evenly into 1440 should be used more detailed discussion of the procedure used by the Campbell for synchronizing the time interval can be found in Instruction 92 of the Campbell manual The most commonly used time interval will be 1440 minutes or one day For this case the first full time interval will always begin at midnight after data collection has begun If data collection is begun on Wednesday the first histogram that will be retrieved when the F10 function is used will be for Thursday 4 3 10 F10 Retrieve Rainflow Data When returning to the test site to retrieve rainflow data the DG must first be reconnected to the Campbell and then the F10 function is used to initiate the data retrieval Upon entering the 21X program no other tasks should be attempted before executing the retrieve data function Executing some of the other functions could result in the rainflow data being erased In addition data should not be entered on the channel description screen When the F10 function is pressed the DG will request the channel description file to be entered This must be the same file that was saved when the F9 function was used to start the rainflow data collection Again the filename extension does not need to be entered 38 The DG will determine the number of input channels being used and the number of elapsed rainflow int
108. pbell must have been programmed and zeroed previously using the F4 function When the F5 key is pressed there is a delay of a couple of seconds before data acquisition is actually begun because the Campbell must first be initialized After the Campbell begins recording data a message will be given at the bottom of the DG screen to press any key to stop taking data Again there is a slight delay between pressing the key and stopping data collection The maximum length of time that the test can cover is discussed in Section 3 1 4 3 6 F6 Retrieve Truck Data After a truck crossing has been recorded using F5 F6 can be used to retrieve the data from the Campbell Only the data recorded during the last execution of the F5 function are retrieved While the DG is retrieving the data the number of scans remaining to be retrieved is displayed in the bottom right corner of the screen 4 3 7 F7 Plot Truck Data The most recent data retrieved using the F6 function can be plotted using the F7 function When the F7 function is used the DG will ask for the channel numbers to be plotted Any combination of the active channels may be specified After the channel numbers have been entered press the return key and the specified channels will be plotted on the screen The plot will be of time on the horizontal axis and a scaled output on the vertical axis The maximum and minimum output readings for the specified channels will also be displayed The scaled output
109. pends on the rainflow period being used The rainflow period is selected by the user and is discussed in Section 4 4 The rainflow period can range from one minute to one day When rainflow data is taken on all eight channels the maximum number of rainflow periods for which data can be taken is 18 For example if a rainflow period of 24 hours is specified then 18 days of data can be taken and stored If the Campbell is allowed to 13 14 BRIDGE TEST DATA SHEET Bridge Location Test Dates Start Finish Instrumentation Description Fatigue Instrument Channel 4 D C I N N i Description Files Channel Description File Zero Description File Rainflow Description File Single Truck Tests Data Files 1 STK Notes 2 OTK Notes 3 STK Notes 4 STK Notes Rainflow Test Rainflow Period Start Date Time Stop Date Time Data File RFL FIGURE 3 1 Bridge Test Data Sheet 15 take data for 19 days then the first day of data will be overwritten and only the data for the last 18 days will be recoverable If a greater number of rainflow periods are desired then the number of channels of data being taken must be reduced The maximum number of rainflow periods can be calculated for a given number of data channels using the following formula 14 556 2 7 21 NE number of rainflow p
110. perCalc template example cal file is provided on a diskette 49 Stress Range Histogram All Intervals M M Es M P M s 2 Percent Occurence M i x x nea aee A e m ru m Mae A a 5 t See 114 152 ZA Z AAR 0 gt gt gt gt gt gt gt gt gt 0 0 gt gt gt t o n d x R C 8 N N m m u Stress Range ksi Figure 5 3 stress Range Histogram Each Interval M M Y Percent Occurence gt r 4 Stress Range ksi Figure 5 4 Cycles per Interval WLLL VME MMM Fatique Damage Factor 51 The data was first processed through program RFLO to create comma separated files The seven files for Channel 1 the channel connected to the transducer at the E detail were loaded into the SuperCalc template The template was used to analyze the data and to produce hard copy plots using a pen plotter The data in Fig 5 2 is one of the files used Figures 5 3 through 5 6 were made using this spreadsheet program Figure 5 7 shows a printout from the spread sheet program The number of cycles effective stress range maximum stress range and the fatigu
111. procedures and calibration equipment for the clamp on transducers were developed Individual bridge completion boxes are used for quarter bridge strain gages All field wiring is done with prefabricated silicone covered wires with mating female and male connectors installed Due to the modular arrangement of the wiring and the use of clamp on transduc ers the system may be installed on a typical bridge in less than four hours The equipment has shown excellent reliability in field tests under both rain and extreme heat The fatigue stress data collection of up to eight locations on the bridge is performed twenty four hours per day for a week or more IMPLEMENTATION The equipment developed in this project provides a simple and reliable method to determine the fatigue damage occurring in a bridge due to service stresses The equipment along with the analysis techniques presented in the report provide the user with the ability to accurately assess the estimated time to visible fatigue cracking The use of the equipment and analysis techniques will allow the continued use of some structures which do not satisfy the current AASHTO fatigue design requirements This will eliminate the unnecessary replacement of these structures vii TABLE OF CONTENTS Page CHAPTER ONE INTRODUCTION 1 CHAPTER TWO BRIDGE TESTING EQUIPMENT 3 2l 6 uk x S y exc S eR AIEO 3 3 ox mox 3 2 2 Equipment
112. rs the DG should be turned off and 37 then restarted After the 21X program is reentered the data file just saved in the Start Rainflow Routine should be loaded into the channel description screen It is not necessary to send this file to the Campbell The data acquisition menu can then be entered and the F9 function can be executed again The rainflow period is synchronized with the real time that is input by the user If a 60 minute interval is used the Campbell will store a rainflow histogram every hour on the hour If the Campbell is instructed to begin taking rainflow data at 1630 a histogram will be written to storage at 1700 and then again at every hour However this first partial histogram which included only 30 minutes of data will not be retrieved when the rainflow data is retrieved using the F10 function Regardless of the time interval used the first time interval of each subsequent day will always begin at midnight For this reason if a time interval is entered which does not evenly divide into 1440 minutes the last histogram of each day will have a different interval length than the specified time interval For example if a time interval of 300 minutes 5 hours is used a histogram will be written to storage at 0500 1000 1500 2000 and 2400 The last interval will be only 240 minutes or 4 hours long This is undesirable from a testing viewpoint and it will also lead to a problem when retrieving the rainflow data since the pr
113. se cables can be connected together to make longer lengths if necessary The cable lengths should be kept as short as possible to minimize noise and signal attenuation 16 Type of Instrumentation Five clamp on strain transducers have been provided with the system If more channels of data are desired then 120 ohm strain gages must be used or more strain transducers acquired If strain gages are used they must be used with the strain gage completion boxes Five completion boxes are provided Once the test plan has been developed the channel description data as described in Section 4 3 can be entered and saved on the Data General computer This will help reduce the time required to set up the test in the field 3 2 Transducer Calibration Each of the strain transducers provides a slightly different amplification of the actual strain values and therefore each transducer must be calibrated individually The calibration data that must be input into the test program for each transducer is the output of the transducer in millivolts volt for a specified stress level The calibration is performed by bolting a transducer to the calibration bar and applying a known load The calibration bar is shown in Fig 2 8 stress in the bar can be calculated using the bar cross sectional area of 75 in and the output of the transducer can be read using the Campbell The output of the transducer represents its calibration for the applied stress l
114. several small desiccant packages These packages contain material which absorbs moisture from the air to prevent possible damage to the Campbell circuits At least once a year these packages need to be taken out of the Campbell and dried lo remove the desiccants the top of the Campbell must be removed Special care should be taken not to disturb the wiring connected to the Campbell The desiccant packages can then be placed in an oven to dry The packages should be dried for 6 hours at 250 F and then replaced in the Campbell 3 5 Field Equipment Check List The following equipment is required in the field to set up and run a bridge test Campbell 21X box 12V battery and box Data General computer Strain transducers 20 cables computer to Campbell and transducers to Campbell C clamps tool box In addition the following equipment may be required depending on the type of test planned strain gages strain gage installation supplies strain gage completion boxes converter for running Data General off of 12V battery voltmeter Camera 3 6 Equipment Set up Once the equipment has been transported to the test site the actual set up can be done fairly quickly Figure 3 3 shows a typical set up of the equipment The order in which the equipment is mounted on the bridge is arbitrary and can be determined based on the method of access being used to get to the various locations on the bridge The battery box must be
115. sts can also be set up Programs have also been written to analyze the data This user s manual has been written to provide the information required to con duct a bridge test Chapter 2 describes the equipment that makes up the bridge testing system and Chapter 3 contains the procedures needed to prepare for a bridge test and to set up the equipment Chapter 4 describes the use of the programs written for conducting a test and Chapter 5 discusses the program written for analyzing the test results The ap pendices contain program listings and additional detailed information Further information on the operation of the system can be found in the Campbell Scientific and Data General manuals CHAPTER TWO BRIDGE TESTING EQUIPMENT 2 1 Equipment List The following major equipment comprises the bridge testing system Campbell Scientific 21X Micrologger aluminum box for micrologger two Stowaway 12 volt batteries two aluminum battery boxes Data General DG One computer computer carrying case five strain transducers five strain gage completion boxes carrying case for transducers and completion boxes 12 50 foot cables 4 90 foot cables 30 three inch C clamps tool box for C clamps transducer calibration specimen 2 2 Equipment Description This section contains a general description of the major pieces of equipment More detailed specifications for the equipment can be found in Appendix C 2 2 1 Campbell 21
116. t will be given requesting a filename for the data to be saved The filename should be in the standard DOS format It is not necessary to enter a filename extension since the DG will automatically assign an extension of 21X to the file The same channel description file can then be retrieved by pressing F1 and entering the filename It is not necessary to type the 21X extension If a mistake is made when entering a filename the backspace key in the upper right corner of the keyboard can be used to go back and correct the entry The F3 key is used to send the channel description data to the Campbell data logger The DG is effectively programming the Campbell to take data on the specified channels This programming takes 1 or 2 minutes and a message is flashed on the DG screen indicating that the Campbell is being programmed It is recommended that the channel description data be saved using the F2 key prior to sending the program using the F3 key The channel data remains in the 21X program until the program is exited but it should be saved in case it is necessary to come back to it at a later time or if the program is abnormally exited due to a power failure When the program is sent the Campbell is turned on and begins to take data However the Campbell does not store the data taken until it is given instructions to do so using one of the commands on the data acquisition menu other keys shown at the bottom of the screen are the DE
117. ting instructions for the Campbell can be found in the Campbell operator s manual 2 2 2 Battery Boxes The two battery boxes are made of aluminum and have construction similar to the Campbell box The outside dimensions of the box are 20 x 14 x ll in and the box is shown in Figure 2 5 The batteries used are Stowaway 12 volt sealed marine batteries rated at 154 amp hours plastic battery box is mounted in the aluminum box to hold the battery in place and to contain any spilled battery acid in the event of a leak The batteries must be slow charged and can be fully charged in about 12 hours using a 15 amp charger 1 amp fuse has been wired into the battery cable to protect the Campbell 2 2 3 Data General Computer and Case lightweight carrying case made by the Zero Corporation has been provided for the Data General One Model Two portable computer The Zero carrying case is filled with foam that has been cut to hold the DG firmly in place during transportation The computer has 256 kilobytes of memory and uses the MS DOS operating system The computer can run off of an internal battery or from an external 7 5 volt power supply The computer and carrying case are shown in Figure 2 6 2 2 4 Transducers Strain Gage Completion Boxes and Case Five clamp on strain transducers and five strain gage completion boxes have been provided Figure 2 7 shows the Zero carrying case which has been provided for storing the transducers and FIGUR
118. utton next to the meter must be pushed to activate it Figure 2 3 shows the location of the meter Below the meter is a light which flashes when the Campbell is taking data The light must be activated by pushing the button next to it The light will only come on after the Campbell has been programmed The light will flash each time the Campbell takes data 4 TEST EXECUTION Once the equipment has been set up properly a test can be controlled and exe cuted directly from the Data General DG computer The Campbell can be programmed using the DG and direct physical access to the Campbell is not required The DG is con nected to the Campbell by a cable which plugs into the serial port on the back of the DG The DG is an IBM compatible machine which uses the DOS operating system It includes 10 megabyte hard disk for permanent storage and a 3 1 2 floppy disk drive that can be used for transferring data to and from other IBM compatible machines The programs supplied on the DG have been written specifically for the purpose of conducting bridge tests The programs provide for a quick and simple means of programming the Campbell recovering data from the Campbell and performing preliminary analysis of the data The specifics of using the programs for conducting a test are discussed in the following sections 4 1 Program Overview The primary program used to conduct bridge tests is titled 21X This program was written by Alec Ta
119. with by typing in the characters RFLO automatically adds the extension RFL Only files with the RFL extension can be accessed by this program The RFL extension was added to your file name in program 21X when you retrieved the data After the file name is typed and a carriage return pressed RFLO will search the disk for the file and retrieve the header information in the file The screen should look like Figure 5 1 after the file has been accessed The number of channels intervals interval length and the minimum and maximum stress ranges of each channel are displayed Also the program defaults the save file to File name 11 The numbered 46 extension refers interval and channel For example 135 21 refers to the data gathered during the second interval on channel one The cursor position is at the bottom of the screen adjacent to Interval The number of the current interval and channel are displayed The data from this interval and channel are the data the program will graph or print out on your command using the function keys The interval and channel can be changed by moving the cursor using the arrow keys and typing in the desired quantities The save file extension is automatically changed to match the current values The save file is comma separated file created by RFLO if you press the F5 key You can also create comma separated files for all intervals and channels by pressing the F8 key printout of the data and an analysis
120. wo significant figures to the right of the decimal point If the value is less than one then the entry must include a zero before the decimal point ex 0 50 For a transducer the MV V value should be determined from a calibration test as described in Section 3 2 Fatigue Detail No AASHTO fatigue category for the detail to be instru mented should be determined in order to establish the maximum stress range that can be expected The AASHTO categories are designated alphabetically from to The alphabetical category should be entered using the fatigue detail num bers shown on the message line at the bottom of the channel description screen Category A is represented by 1 category B by 2 and so forth until category E which is represented by 7 When a fatigue detail number between 1 and 7 is en tered default values for maximum and minimum stress ranges are automatically entered into the next two columns The default maximum stress range value is the expected maximum stress for the specified type of detail and the minimum stress range is set at a level sufficient to prevent recording electronic noise The default values may be modified if desired When one channel is modified the other channels with the same fatigue detail number are automatically updated with this modified value F5 will restore the Sr Max and Sr Min values to the original default values The default values are shown below 29 CATEGORY DETAIL NO Sr MAX Sr

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