钢-超高性能混凝土组合板横向受弯静力试验及有限元模拟

Static test and finite element simulation analysis of transverse bending of steel-ultra-high performance concrete composite slabs

为了研究钢-超高性能混凝土(UHPC)组合板的受弯性能,开展8块该类组合板的受弯试验,分析正、负弯矩作用下的受弯破坏开展全过程.在正弯矩作用下,组合板受弯破坏经历了线弹性阶段、裂缝开展阶段和屈服阶段,结构刚度两次衰减的拐点分别是界面滑移与钢板屈服,结构破坏时加载点附近UHPC局部压碎且剪弯段及端部界面出现脱空现象;在负弯矩作用下,UHPC层出现横向裂缝导致结构刚度第一次下降,随着裂缝的发展,截面内力重分布使得钢筋应力持续增大直至屈服,最终主裂缝宽度过大导致结构刚度严重衰减,组合板因UHPC层受拉断裂而破坏.采用有限元软件ABAQUS,建立非线性有限元模型.模型中考虑界面接触、材料非线性、混凝土损伤塑性模型等,模拟试验全过程.在与试验结果进行对比分析的基础上,分析影响钢-UHPC组合板抗弯性能的主要因素,包括界面黏结方式、纵筋配筋率、栓钉数及布置,研究这些因素对组合板抗弯极限承载力、结构刚度、跨中挠度等力学性能的影响.

A series of static load tests were performed on eight steel-ultra-high performance concrete(UHPC)composite slab specimens in order to analyze the flexural properties of steel-UHPC composite slabs under both positive and negative bending moments.The whole damage processes of the specimens were recorded and analyzed.In the case of positive bending moment loading,the specimens experienced three distinct stages,i.e.,the linear elastic stage,the crack-developing stage,and the yield stage.The two turning points on the load-deflection curves represent the onset of interfacial slipping and the yielding of the steel plate,respectively.When the specimens approached failure,the UHPC was locally crushed near the loading point and the steel-UHPC interface was separated at both the shear-bending zone and the specimen end.In the case of negative bending moment loading,a first decrease of the stiffness of the specimens was related to the initiation of transversal cracks in the UHPC layer.The internal forces redistributed in the specimens with the cracks developing,leading the tensile stress in the steel bars to continuously increase until yielding.Then the crack width excessively developed and the stiffness of the specimens severely decreased.The specimens finally failed because of the fracture of the UHPC layer.The load tests were simulated using a comprehensive nonlinear finite element(FE)analysis through the software Abaqus.The FE models considered both the contact nonlinearity and material nonlinearity.The concrete damaged plasticity was considered for the UHPC to simulate its deterioration process.The analysis results were compared to the test results.The factors that influence the flexural performance of the steel-UHPC composite slabs(e.g.,the ultimate capacity,the flexural stiffness,and the deflection)were analyzed,including the interfacial adhesion mode,the longitudinal reinforcement ratio,and the number and arrangement of studs.