接缝处纵筋连续预制节段梁弯剪受力机理试验研究

摘要:

基于网格抗剪配筋原理，提出了接缝处纵筋连续预制节段梁概念。设计3根试验梁，将接缝类型作为试验参数，以试件裂缝发展、钢筋应变、破坏模式、刚度、承载力为研究对象，开展弯剪试验。结果表明，接缝处纵筋连续预制节段梁中腹板水平纵筋有效承担了由剪力作用引起的截面上轴向拉力，与箍筋同样起到抗剪作用；腹板水平纵筋在接缝位置处的连续可以更好地抑制斜裂缝的发展，限制主裂缝的宽度，从而有效提高预制节段梁结构的刚度；从试件腹板开裂至试件破坏的整个加载过程中，纵筋连续预制节段梁接缝附近节段受力基本满足平截面假定，各项力学行为与整体梁相似。试验结果充分验证了接缝处纵筋连续是预制节段梁从受力性能上消除“接缝”的必要手段。

Abstract:

Based on the principle of grid shear reinforcement， the concept of precast segmental girders with continuous longitudinal reinforcements across joints was proposed. Three test beams were designed， and the joint type was taken as the test parameter. The bending shear test was carried out with the research objects of crack development， reinforcement strain， failure mode， stiffness and bearing capacity. The test results show that the longitudinal reinforcement of webs across joints effectively bears the axial tension caused by shear force， and plays the same role of shear resistance as the stirrup. The continuous longitudinal reinforcement can restrain the development of oblique cracks and limit the width of main cracks， so as to effectively improve the stiffness of precast segmental beam structure. During the whole loading process from the cracking to the failure of continuous longitudinal reinforcement precast segmental beams， the structure near the joint satisfies the plane cross-section assumption， and the mechanical behavior is similar to that of the whole beam. The test results fully verify the necessity of continuous longitudinal reinforcement across the joint of precast segmental beams.