为充分发挥装配式工业化程度高和钢-混组合结构优良力学性能的优势,提出一种装配式双拼槽钢-混凝土组合楼板,对3组简支组合楼板试件进行了四点加载试验,研究了该组合楼板的竖向静载下力学性能.分析了楼板裂缝、挠度、应变(钢筋、钢梁、混凝土板)随荷载发展规律;基于极限平衡法,提出了考虑受拉薄膜效应和刚度强化系数的承载力计算公式.结果表明:组合楼板的变形呈双向板特征,试件破坏时均出现板顶角部裂缝和弧形裂缝,混凝土板底中心区域为网状裂缝和向角部延伸的斜裂缝,双拼主梁发生塑性弯曲;在楼板的中心挠度达到l0/40时,试件荷载分别为327.63 kN、436.92 kN和406.12 kN,组合楼板承载力较高;钢筋的应变发展在垂直钢梁方向较大,沿着塑性铰线屈服;考虑受拉薄膜效应和刚度强化系数的计算公式与试验结果吻合良好,准确地预测了楼板荷载-挠度全过程曲线.
In order to give full play to the advantages of the high degree of industrialization of assembly and the excellent mechanical properties of steel-concrete composite structures,a kind of assembled double-slotted channel steel-concrete composite floor slab was proposed.Three groups of simply supported composite floor slab specimens were tested under four-point loading,and the mechanical properties of the composite floor slab under vertical static load were studied.The development law of floor cracks,deflection and strain(steel bar,steel beam,concrete slab)with load was analyzed.Based on the limit equilibrium method,the bearing capacity calculation formula considering the tensile membrane effect and stiffness strengthening coefficient was proposed.The results showed that the deformation of the composite slab is characterized by two-way slab.When the specimens are destroyed,the corner cracks and arc cracks appear on the top of the slab,the central area of the concrete slab bottom shows mesh cracks and oblique cracks extending to the corner,and the plastic bending of the double main girder occurs.When the center deflection of the floor reaches l0/40,the load of the specimens is 327.63 kN,436.92 kN and 406.12 kN respectively,and the bearing capacity of the composite floor is higher.The strain development of the steel bar is larger in the direction perpendicular to the steel beam and yields along the plastic hinge line.The calculation formula considering the tensile membrane effect and the stiffness strengthening coefficient is in good agreement with the test results,and the load-deflection curve of the floor is accurately predicted.