Experimental and numerical investigation of the mechanical behavior of a cable-stayed bridge with shell-shaped pylons

Abstract

A novel cable-stayed bridge (CSB) with shell-shaped pylons was first proposed, of which the shell-shaped pylons were uniquely composed of five concrete-filled steel tube (CFST) pylon arches (PAs) and curved circular hollow steel transverse braces. To investigate the force transmission mechanism of this new type of CSB, a static loading test of a 1:25 scale model of the whole bridge and finite element analysis (FEA) of the prototype bridge were performed. The results showed that under the action of vehicular load the shell-shaped pylon and main girder jointly shared the load effect in a distribution ratio of 1:9, and the stress levels of the pylon arch in the middle (PAm) and the pylon arch immediately next to it (PAn) were much greater than the outermost pylon arch (PAo), and the maximum stress occurred at the bottom section of PAs. However, the location where the maximum stress occurred under permanent load would shift to the junction section of the curve and the straight segment of the PAs. Meanwhile, the stress levels of PAm, PAn, and PAo were almost equal under the temperature load, and the maximum stress occurred at the apex of the arch. Furthermore, the refined FEA results of the steel–concrete composite pylon pedestal showed that there were obvious stress concentrations at the steel tubular intersecting joints of the PAm and PAn and the connection area between the connecting steel plate and the steel tube in the pylon pedestal. Nevertheless, the pylon pedestal still behaved elastically under the ultimate limit state.