Experimental and numerical investigation on mechanical performance of continuous steel-UHPC composite slabs

Abstract

Ultra-high-performance concrete (UHPC) has recently gained popularity for use in bridge constructions. Innovative steel-UHPC composite slabs (SUCS) with perfobond rib shear connectors were utilized as the deck slabs of the Fulong Xijiang Bridge (a composite cable-stayed bridge with span length of 580 m) in Foshan, China. The SUCS functions as multi-span continuous slabs supported on the transverse diaphragms of the girder. Two full-scale experiments were conducted to explore key mechanical performance aspects of continuous SUCS, including the load-deflection response, strain development, cracking behavior, moment redistribution and interface slipping behavior. The specimens experienced ductile flexural failure, and significant moment redistribution occurred with the formation of three plastic hinges. A detailed finite element model (FEM) was established to simulate the tested continuous slabs and also simply supported SUCS reported in the literature. A new constitutive model is proposed to describe the strain-hardening behavior of UHPC. Fasteners based on the shear stiffness formula and load-slip relationship reported in the literature modeled perfobond rib shear connectors and studs, respectively. The predicted results of deflection, interface slip and failure mode correspond well with experimental results, indicating that the FEM accurately simulates SUCS. In addition, comprehensive parametric studies performed using the validated FEM revealed the influences of different parameters on mechanical performance of continuous SUCS.