Experiment and numerical study on the static and fatigue behavior of a novel deck joint

Abstract

To increase the prestressing efficiency and alleviate the longitudinal cracking in the concrete slab of composite cable-stayed bridges, a novel deck joint was proposed. The joint is composed of epoxy joint and concrete wet joint, which allows to introduce the prestress before the precast deck slabs are connected to the steel girder, therefore significantly increases the prestressing efficiency. Full-scale test models were fabricated and tested under repeated negative bending load, with the main variables being prestress level and fatigue load amplitude, and the evolutions of displacement, strain, crack width and moment distribution were investigated. A numerical study was conducted to investigate the effects of joint geometries and prestress level on the joint strength, the moment distribution and the neutral axes. The failure mechanism of the joint was revealed and a calculation method was recommended. Results show that the failure modes of the test models are rebar fracture in the tension zone, and the prestress has significant benefits on the joint behavior. The moment distribution between the precast and the post-cast sections is affected by the prestress level and the width ratio of epoxy and wet joints. The recommended method can predict the static flexural resistance of the joint with accuracy.