不同加载方式及配束比下节段预制箱梁受力性能试验  

Force bearing performance test of precast segmental bridge beams with different tendon ratios under different loads

作　　者：袁爱民[1] 何雨[1] 戴航[2] 孙大松[3] 

机构地区：[1]河海大学土木与交通学院,江苏南京210098 [2]东南大学土木工程学院,江苏南京210096 [3]江苏省交通规划设计院股份有限公司,江苏南京210005

出　　处：《长安大学学报（自然科学版）》2016年第1期58-68,共11页Journal of Chang’an University(Natural Science Edition)

基　　金：江苏省交通科学研究计划项目(2013Y11);江苏省自然科学基金面上项目(BK2011748);博士点基金项目(20100094120013)

摘　　要：体内体外不同配束比的节段预制混凝土箱梁已在桥梁建造中得到了广泛的应用，其受力性能主要受配束比和加载方式的影响。将4种不同配束比的节段预制箱梁在2种不同加载方式下的受力行为进行对比分析，并将试验结果与国内外类似试验结果进行对比，提出了节段预制箱梁正截面抗弯极限承载力计算公式。研究结果表明：不同加载方式下，最大挠度及胶接缝张开位置不同；弯剪耦合作用使梁体承受的竖向荷载和竖向挠度降低；单点集中加载使受压区高度和胶接缝张开宽度增大。不同配束比时，体内柬越多，开裂弯矩和极限弯矩均越大；受压区高度越大，胶接缝宽度越小；体外束的极限应力增量可以达到35％～55％。单点集中加载且预应力配筋率f0〈2％时，破坏模式为箱梁顶板混凝土压溃后的脆性弯曲破坏；．0〉2％时，破坏模式为弯剪破坏，节段间有错动；1／3点处两点加载时均为弯曲破坏；提出的公式在充分考虑预应力筋极限应力和受压区预应力筋增量的基础上，计算值与试验值吻合较好。Segmental prestressed concrete beams （SPCB） with hybrid tendons have been widely used in construction of bridge structures, and the performance of which is affected by two important factors, tendon ratio and combined load（bending and shear）. This paper presented an experimental investigation of structural behaviors of SPCB under four different tendon ratios and two types of loads. Comparison between this test results and the similar tests at home and abroad was carried out, and a new calculation formula of flexural bearing capacity was presented. The results show that the maximum deflection and the joint opening location are different under different types of load. The interaction of shearing and bending reduces the vertical load and vertical deflection, and the concentrated loading increases the height of compressive region for beams and the width of joint opening. For beams with different tendon ratios, the more internal tendons it has, the higher the cracking moment and the failure moment are, and the greater the height of compressive region is, the smaller the width of joint opening will be. Furthermore, the stress increment of external tendons is approximately 35%-55% of the ultimate strength. When the segmental beam is subjected to concentrated load and the reinforcement ratio p is less than 2%, flexural failure occurrs after concrete crushing. When the reinforcement ratio p is greater than 2%, flexural and shear failure occurrs, and there is a sliding between segments. If beams are subjected to one-third loading, only flexural failure occurrs. Formula presented in this paper is in accordance well with the test results on the basis of considering fully of the ultimate stress of prestressed steel and the effect of prestressed steel in compressive region. 3 tabs, 11 figs, 21 refs.

关 键 词：桥梁工程 节段预制混凝土梁 混合配束 组合加载 受力行为 抗弯承载力 

分 类 号：U441[建筑科学—桥梁与隧道工程]