DYNAMIC BEHAVIOR OF SLANT-LEGGED RIGID-FRAME HIGHWAY BRIDGE

The slant-legged rigid-frame bridge is one type of the most widely used highway bridges. However, very few dynamic characteristics of this type of bridges have been reported. The objective of this paper is to investigate the dynamic response of a slant-legged rigid-frame bridge to one or two trucks (side by side) passing over the rough bridge deck. The bridge was modeled as a space bar system. Trucks were modeled as a nonlinear system with 12 degrees of freedom according to the HS20-44 truck design loading specified in the American Association of State Highway and Transportation Officials (AASHTO) specifications. The road surface roughnesses of the approach roadways and bridge decks were generated from power spectral density function. Maximum dynamic responses of each rigid frame at different sections were determined for two trucks through changing their transverse positions with different speeds and road surface roughnesses.