Computer Modeling Analysis in Bridge Evaluation.

摘要

This is an interim report of the first year's work on computer modeling analysis in highway bridge evaluation. The study was carried out because of the need for a more accurate method of assessing the bridge dynamic response and predicting fatigue life of highway bridges under moving live loads. The road surface roughness for the classes of very good, good, average, and poor roads was generated in accordance with the International Organization for Standardization specifications. According to the H20-44 and HS20-44 trucks, two nonlinear vehicle models with seven and twelve degrees of freedom were developed and validated by the experimental data. The prestressed concrete and steel highway bridges were designed according to AASHTO specifications as bridge models. Two percentage of critical damping was assumed for the bridge. The impact percentages of moment, deflection, and end shear of prestressed concrete bridges for different bridge span lengths, vehicle speeds, and road surface roughness were obtained and compared with values specified by AASHTO specifications and the Ontario Highway Bridge Design code. Also, the reliability-based methodology was introduced. The fatigue life of both noncomposite and composite steel beam bridges for different vehicle speeds, classes of road surface, and levels of reliability was calculated.