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Steel bridge erection requires a series of processes in the construction site including shipping, sequentially lifting, and installing bridge components that are fabricated in the factory. Each process is critical and the risks are high due to the fact that conditions in the field are far more complex than in the factory. A detailed lifting plan is important to ensure the successful completion of steel bridge erection. In this particular study, Building Information Modeling (BIM) tools were used to precisely establish the 3D model of a π shape steel arch bridge following 2D detailed design drawings. Combined with the lifting and installation sequences described in the original lifting plan which were prepared by using 2D drawings and explanations, a 4D simulation for the steel bridge erection was produced and used to review and improve the lifting plan.A spatial conflict of steel component and concrete abutment was detected and corrected in time by postponing pouring of a part of the concrete. Three out of the four issues raised by using the 4D lifting plan were verified and the effectiveness of simulation was confirmed in the construction site.

This study focuses on improving the mechanical behaviors of pultruded glass fiber-reinforced polymers (GFRP) composite material. A combined GFRP member was prepared by the insertion of a second GFRP tube inside the prototype GFRP member and then filling the compartment with epoxy resin mortar to combine both members. Analysis of the combined member was performed to consider improvement of the stiffness and strength of the material to meet design requirements. Four different types of GFRP deck specimens and five different types of GFRP beam specimens were investigated by performing the three-point bending test to obtain their ultimate strength, ultimate displacement, stiffness, and corresponding failure modes. Observations from the experiment showed that infilling the rectangular GFRP tube member can effectively increase the GFRP specimen’s stiffness and ultimate strength. Finally, the Euler beam and Timoshenko beam theories combined with the transformed section method were used to obtain the stiffness of the combined GFRP members, and then compare those stiffness with the experimental results.

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In this paper, the mechanical behaviors of bridges with unseating prevention devices in the superstructure were investigated. These devices can prevent bridge from unseating and divert most of the seismic forces from transferring to the bridge columns. The models of the rubber bearing, restrainer, and shear key were proposed and implemented into the SAP 2000 to obtain the seismic response of the bridge. The nonlinear time history analysis was used to determine the time history response of the superstructure of the bridge. In the meantime, the Hilbert–Huang Transform (HHT) was used to transfer the displacement–time responses of the superstructure of the bridge into the time–frequency domain, while the spectra are a function of both frequency and time. The spectra of the HHT can be used to determine the operation sequences of the unseating prevention devices.