Analytical and experimental studies on torsional behavior of hybrid truss bridge girders with various connection joints

A hybrid truss bridge (HTB) is a bridge constructed by replacing the concrete webs of a pre-stressed box girder bridge with steel truss webs. With its open web section, HTB offers advantages of high structural efficiency and excellent aesthetic appearance. The core technology of HTB is the connection system between the steel trusses and the concrete deck. Since the open web section of a HTB decreases the torsional capacity, precise analysis of the torsional behavior of the open web section with respect to the connection joint type is needed to ensure the safety of HTBs. In this study, the torsional capacity of HTB was calculated using the torsion formula derived based on the steel plate thickness conversion equation for corrugated steel web plates and the space truss theory. The torsion formula was verified by performing a parametric study using a commercial finite element program. Next, the torsion analysis results of the HTB girder were compared to experimental results to evaluate their accuracy. Finally, the simulation, experimental, and torsion formula results were compared to evaluate the feasibility of using the formula in design.