Tests and Ratings of Short‐Span Steel Bridges

Abstract

A series of diagnostic tests were performed on three short‐span, two‐lane, steel‐girder bridges. Tests were performed with stationary and moving test trucks placed on the bridges one at a time and side by side. Wheel‐load distribution factors were calculated from results of the stationary‐truck test, and impact factors were calculated from results of the moving‐truck test. Girder strains were calculated using the American Association of State Highway and Transportation Officials' simplified bridge analysis with the measured wheel‐load distribution factors. The calculated girder strains were consistently larger than measured values. The results illustrate some of the inaccuracies of the wheel‐load distribution‐factor approach. Impact factors are calculated by various methods. Comparisons are made between impact factors for the most critically loaded girder and impact factors determined from the combined response of all the girders. The impact factors based on the combined response of all the girders tend to be larger. Impact factors calculated from side‐by‐side truck test results tend to be larger than those calculated from single‐truck tests. Bridge ratings based on the test results are presented and discussed.