Effective width of timber-concrete composite beams with crossed inclined coach screw connections at the serviceability state

Abstract

To support the design and application of timber-concrete composite (TCC) floor systems, the effective width of the TCC beams with crossed inclined coach screw connections at the serviceability state was evaluated in this study. The bending tests on the TCC beams with different slab widths were conducted to assess the shear lag effect in concrete slab and discuss the influence of slab width on the bending performance of TCC beams. A nonlinear finite element (FE) model for TCC beams was established in ABAQUS 6.14 and validated by the experimental results. Based on the experimental and FE studies, an extensive parametrical analysis was performed to evaluate the effect of various factors on the effective width of TCC beams. The presence of shear lag effect was proved by the experimental strain distributions in the concrete slab, and the shear lag effect was found more apparent for the tension strain at the bottom of concrete slab than the compression strain at the upper surface of slab. The FE numerical results showed high agreement with the test results in terms of the macro and micro bending performances of the TCC beams. In addition, the parametrical studies indicated that the effective width of TCC beams mainly depends on the load type, slab width-to-span ratio, slab thickness, and connection stiffness. Finally, for practical use, a general formula was proposed to calculate the effective width of the TCC beams.