Design and Analysis of Concrete-Filled Rectangular Steel Tubular Truss-Arch Composite Bridge Stiffened with PBL

Under the influence of long time load actions, shrinkage and creep of concrete, temperature variation, and concrete pouring quality, debonding may occur between steel tube and concrete. Debonding affects the mechanism behavior of arch rib and joint and even threatens the integrity of an entire bridge. To reduce such possibility, a concrete-filled steel tubular arch bridge stiffened with perfobond ribs (PBL) is proposed. Based on a concrete-filled rectangular steel tubular truss-arch composite bridge stiffened with PBL in Xining City, Qing Hai province, we conduct force analysis of the bridge on the aspects of the arch ribs and the truss-arch composite system. According to the mechanical properties of the bridge, we establish finite-element models, including joint models in which web members bore relatively large axial force and a typical arch rib model. Based on the models, the local mechanical property of joints, and the interfacial properties between steel tube and concrete under solar radiation are studied. Results show that PBL reduces the length of force transmission and improves the stress and deformation concentration of the joints. PBL also alleviates the debonding between steel tube and concrete. This bridge scheme meets the requirements of function, aesthetics, and safety.