钢-混凝土预制混合梁受力性能分析

Analysis on mechanical performance of precast hybrid steel-concrete beam

通过对4个钢-混凝土预制混合梁试件进行拟静力试验,研究了该预制试件的破坏模式、受力过程及受力机理。采用有限元软件ABAQUS对钢-混凝土预制混合梁的受力性能进行模拟,研究了钢材屈服强度、纵筋配筋率和钢梁长度对其受力性能的影响,并分析了钢、混凝土梁两者间刚度及承载力的匹配关系。研究结果表明:钢-混凝土预制混合梁最终破坏表现为混凝土梁端出现塑性铰,而端部钢梁在整个加载过程中保持完好,钢与混凝土连接节点能可靠传递两者间应力。提高钢材屈服强度和增加纵筋配筋率可提高承载力,其中增加纵筋配筋率的提高效果更明显;随着钢梁长度的增加,承载力逐渐增大,但初始刚度呈线性降低。根据研究结果给出了该类型预制构件的设计建议:混凝土梁与钢梁设计受弯承载力比(Mc/Ms)取值范围宜为0.8～1.0,端部钢梁长度取值范围宜为100～200 mm;箍筋加密区范围起算点应取混凝土梁端截面而不应取柱边。

In order to study the failure mode,loading process and mechanism of precast hybrid steel-concrete beams,four precast hybrid steel-concrete beam specimens were tested under cyclic loading.The mechanical performance of precast hybrid steel-concrete beams was simulated by the finite element software ABAQUS.Parametric studies were conducted to investigate the influence of steel yield strength,longitudinal reinforcement ratio and steel beam length on the mechanical performance of precast hybrid steel-concrete beams.Furthermore,the matching relationship between the stiffness and bearing capacity of the steel beam and the concrete beam was also analyzed.The results show that the failure mode of precast hybrid steel-concrete beam is the formation of plastic hinge at the concrete beam end,while the steel beam remains intact during the entire loading process.The steel-to-concrete connection joints can reliably transfer the stress between different members.The increase in steel yield strength and longitudinal reinforcement ratio can improve the bearing capacity of precast hybrid steel-concrete beam,and the effect of longitudinal reinforcement ratio is more obvious.With the increase of the steel beam length,the bearing capacity gradually increases,but the initial stiffness decreases linearly.Based on the research results,some reasonable design suggestions for such precast members were proposed:the range of flexural capacity ratio of concrete beam to steel beam should be 0.8-1.0;the range of steel beam length should be 100-200 mm;the range of dense stirrup area should be calculated from the concrete beam end instead of the column edge.