Dynamic Behaviors and Loading of Steel Tied-arch Bridges due to Moving Vehicles

The purpose of this study is to investigate the dynamic behaviors and impact loading of steel tied- arch bridges. First, a brief description of the analyzed bridges is given. Then, analytical theory is presented, including the vehicle, bridge, and road surface models. A vehicle is simulated as a three- dimensional nonlinear model. The bridge is treated as a space structure consisting of three- dimensional frame elements. The road profile is modeled as a stationary Gaussian random process that is described by a power spectral density (PSD) function. Then, the bridge’s free and forced vibration characteristics are given. Finally, the effects of vehicle speed, number of moving vehicles, and bridge rise-to-span ratio on the bridge’s dynamic loadings, as well as an evaluation of the impact factors/dynamic allowance specified in AASHTO specifications, are presented. Results of this research are applicable to the design of steel tied-arch bridges.