CHARACTERIZATION OF PRESTRESSED CONCRETE AND STEEL BRIDGE GIRDERS AGAINST HEAVY TRUCK LOADING

Heavy truck traffic affects the service life of highway bridge superstructures. Damage typically occurs in the bridge deck and in the superstructure main elements. This damage may be mainly due to a bending moment that could exceed the load capacity of the bridge, and/or fatigue damage of the super structure girders ( steel bridges). The goal of this research is to characterize bridge population sensitive to bending moment. This was done based on a static analysis of steel and prestressed concrete ( PSC) girder bridges of different configurations subjected to the AASHTO design truck ( HL-93), the 97-kips trucks ( 97-S and 97-TRB), and AASHTO legal rating truck ( 3S2). Moreover, based on the site-specific WIM data, the site-specific representative heavy vehicles ( 160 and 170 kip) and the site specific fatigue truck ( 85 kip) were analyzed. For static analysis, five different steel and PSC girder bridges of different practical spans ( 30, 60, 90, 120, and 140 ft) and configurations were modeled by two different programs to provide confidence on the accuracy of the analysis, a commercial program ( CSiBridge) and an AASHTOWare Bridge Rating program. The results provide the bending moment at the most critical sections of girders under the selective heavy truck presence case. For the PSC bridges, the site-specific representative heavy vehicle induced the most critical load case for the 60- to 100-ft long PSC bridges; however, the 30-ft-long steel bridge was unsafe under the application of the strength-I load factors but turned to be safe with the application of the strength-II load factors.