Fatigue behaviour of joint-free bridges with steel and GFRP-reinforced ECC link slabs

Abstract

Engineered Cementitious Composite (ECC) link slabs provide a feasible alternative to leaking expansion joints for improving long-term durability of slab-on-girder bridges. The use of Glass Fiber Reinforced Polymer (GFRP) rebars have become increasingly common for inducing superior chemical resistance in bridge decks in salt-prone locations. Existing literature lacks experimental research on effects of fatigue load on joint-free bridges with ECC link slabs reinforced with GFRP bars. This paper presents results of experimental testing of joint-free bridges with GFRP or steel-reinforced ECC link slabs subjected to static and fatigue (up to 1 million cycles at 4 Hz) loadings. Comparative performance between GFRP and steel-reinforced ECC link slab bridges is described based on load–deflection or moment-rotation behaviour, strain characteristics and crack development in pre-fatigue, fatigue and post-fatigue stages. After 1 million fatigue cycles, the GFRP-reinforced ECC link slab exhibited smaller crack widths and higher deformation capacity while its incorporation provided superior ductility and deformation capability of the full bridge. A finite element (FE) model was also developed using experimental results to simulate load–deflection behaviour of composite deck-steel girder joint-free bridge with ECC link slab subjected to fatigue loading. Parametric FE study showed that increasing mean stress level caused increased composite deck-steel girder deflection while link slab deflection was limited by bridge span deformation.