Experimental and numerical investigations on flexural behavior of stress-laminated timber-concrete composite decks with butt joints

Abstract

Stress-laminated timber (SLT) products are increasingly used in the field of timber bridges. However, existing butt joints and significant vibrations of SLT greatly hinder its application. Allying a concrete slab on the top of an SLT deck to form a composite structure can effectively ameliorate these deficiencies. In this study, the flexural behavior of SLT-concrete composite decks (SCCD) was investigated via four-point bending tests. The test parameters include prestress level, butt joint frequency, and concrete slab thickness. Comparative analysis against the SLT deck revealed substantial improvements in the load-carrying capacity and initial bending stiffness of SCCD, with increases of 30.2 % and 86.2 %, respectively. Additionally, the improvement is more significant when the concrete slab thickness increases. The presence of butt joints reduces the structural performance of SCCD, and its stiffness reduction degree is slightly greater than that of the SLT deck at the same butt joint frequency. Furthermore, a finite element (FE) model for the SCCD was established, and the numerical simulation showed good agreement with the test results in terms of failure modes and bending performance. Finally, the bending stiffness reduction coefficient for the SCCD was recommended by considering various butt joint frequencies based on tests and numerical simulations, which can serve as a reference for practical engineering.