LOADING HISTORY OF HIGHWAY BRIDGES: COMPARISON OF STRESS- RANGE HISTOGRAMS

THE RESULTS OF A LOADING HISTORY FIELD TEST ON A RURAL HIGHWAY BRIDGE IN MARYLAND ARE PRESENTED. TWO WAYS OF DATA REDUCTION ARE COMPARED: ONE TECHNIQUE NOTES ONLY ONE STRESS EVENT PER TRUCK PASSAGE, WHILE THE OTHER TECHNIQUES PRODUCES SEVERAL EVENTS FOR EACH VEHICLE. THE COMPOSITION AND WEIGHT OF THE TRUCK TRAFFIC ARE PRESENTED, ALONG WITH A NUMBER OF OCCURRENCES OF MULTIPLE CROSSING. SEVERAL METHODS OF ESTIMATING THE FATIGUE LIFE OF THE BRIDGE ARE ALSO ATTEMPTED. SOME CONCLUSIONS ARE THAT SIGNIFICANT DIFFERENCES IN THE SHAPE OF STRESS-RANGE HISTOGRAMS CAN RESULT, DEPENDING ON THE INCLUSION OR EXCLUSION OF THE SEVERAL SECONDARY STRESS RANGES, BUT THAT FOR STRESS RANGES ABOVE 3.0 KSI NO SIGNIFICANT DIFFERENCES IN THE HISTOGRAMS ARE FOUND. HIGHER AVERAGE STRESS RANGES WERE PRODUCED BY MULTIPLE CROSSINGS THAN BY SINGLE CROSSINGS. IT WAS ALSO CONCLUDED THAT THE MAIN LOAD-CARRYING MEMBERS OF THIS BRIDGE ARE NOT LIKELY TO SUFFER FROM TRAFFIC-INDUCED FATIGUE DISTRESS. /AUTHOR/