Analysis of Geometric Nonlinearity of Special-Shaped Arch Bridges

Abstract

Application of nonlinear behavior laws is relatively complicated and difficult to master because of the unique configurations of special-shaped arch bridges. In this study, a self-compiled program is used to analyze the nonlinear behavior laws of five special-shaped arch bridges with distinct characteristics. Essentially, the beam-column effect is determined to be the most influential factor for arch-beam composite butterfly-shaped arch bridges, the large displacement effect has the greatest influence for flying swallow-type tied arch bridges, and the cable sag effect is the main factor for arch-tower cable-stayed bridges. For thrust crescent-shaped arch bridges, however, the influence of all nonlinear factors is rather little and can be neglected. In addition, the cable sag effect of inclined cables is more noticeable than that of vertical cables, and all nonlinear factors significantly influence the cable forces. Therefore, the cable sag effect should be considered, and the tension of inclined cables must be calculated by nonlinear methods. Moreover, because the deck slabs and crossbeams only carry load sand are not subject to force as a part of the entire structure, the nonlinear influence on their inner forces is negligible. Therefore, linear methods are appropriate; however, the large displacement effect should be considered when the displacement is calculated.