Mechanical properties and engineering application of single-span steel-concrete double-sided composite beams

Abstract

This study investigates the mechanical properties of single-span steel-concrete double-sided composite beam, and describes the first practical application of this beam type in building structure. Four steel-concrete composite beams were tested with different parameters that govern the thickness and material strength of the bottom concrete slab. As a control, one ordinary composite beam without a bottom concrete slab was also tested for comparison. The failure mode, load carrying capacity, stiffness, interfacial slippage, internal force of the bottom concrete slab and cross sectional strain distribution are analyzed for all specimens. The results show that most of the damage occurred in the front section of the bottom concrete slab. The bearing capacity and stiffness of the double-sided composite beam are greatly improved compared to the ordinary composite beam. The stability of the lower steel beam flange in the negative moment region is also higher in the composite beams. Theoretical models of the bearing capacity for the various loading stages agree well with test results. The tests also show that interfacial slippage can be effectively mitigated through a full shear connection design. Additionally, to better improve the mechanical performance of the composite beams, the bottom concrete slab should be made with high strength materials or possess a large thickness. Finally, the first-ever practical application of the double-sided composite beam in a building structure is described in this paper.