Parametric Analysis for Post-Tensioned PSC Composite Girder Bridges Using 2,360 MPa High-Strength Strand

In this paper, design variable analysis is performed to the post-tensioned PSC composite girder bridge by applying the Korea Road Bridge Design Code (limit state design method). As design variables, span length, initial allowable prestress, concrete design compressive strength, construction stage, and rebar ratio are considered, and a method for exhibiting the characteristics of a 2,360 MPa high-strength strand is studied. The standard section of the Korea Expressway Corporation EX girder is selected for variable analysis. After designing the PSC composite girder bridge for each span that satisfies the serviceability limit state, the satisfaction of the ultimate limit state requirement is examined. For the long-term behavior analysis by construction stage, the AEMM method considering the aging of concrete is applied. For design flexural strength, the strain compatiability analysis is conducted for design flexural strength of PSC composite girder. As a result of the parameter analysis, as the span length increases, the amount of prestressing tendons introduced in the PSC composite girder increases, and the depth of the plastic neutral axis sharply increases. Based on the research results, as a way to design a PSC composite girder bridge more rationally, it is proposed to increase the initial allowable prestress to 0.95f_py of 2,360 MPa high-strength strand and increase the allowable tensile stress at the bottom surface of the PSC girder.