牛腿式接缝分段预制拼装盖梁的受力性能

Static behavior of segmental precast assembled cap beam with corbel joints

为探索牛腿式接缝分段预制拼装预应力混凝土盖梁的静力性能,本文开展了静载试验及有限元模型参数分析,探讨各个影响因素对其受力性能的影响。采用粘性接触单元模拟了牛腿接缝界面的相互作用。研究结果表明:分段预制拼装与整体预应力混凝土盖梁模型相比,开裂荷载和破坏形态基本相同,然而极限承载力和极限变形能力均有明显下降;牛腿接缝界面是分段预制拼装预应力混凝土盖梁的薄弱环节,破坏时临近接缝界面的受拉区混凝土完全分离;此外,牛腿接缝位置设置应综合考虑减轻盖梁的最大吊重与极限承载力之间的冲突;增加预应力筋数量或增大盖梁截面高度,均是提高牛腿式接缝分段预制拼装预应力混凝土盖梁极限承载力的有效措施。

The load test and finite element model parameter analysis are conducted to explore the static behavior of a segmental precast assembled prestressed concrete cap beam with a corbel joint structure,and the influence of various factors on its mechanical properties is discussed.Interaction at the corbel joint interface is simulated by using viscous contact units.Results show that although the cracking load and failure mode of the segmental precast assembly are basically the same as those of the integral precast PC cap beam model,the ultimate bearing capacity and ultimate deformation capacity of the segmental precast assembly have reduced significantly.The corbel joint interface is a weak link in the segmental precast assembled concrete cap beam.The concrete in the tensile zone near the joint interface is completely separated when damaged.In addition,the setting of the corbel joint position should be considered carefully to reduce the conflict between the maximum lifting weight and the ultimate bearing capacity of the cap beam.Increasing the number of prestressed tendons or the section height of the cap beam is an effective measure to improve the ultimate bearing capacity of segmental precast assembled concrete cap beams with corbel joints.