可提离式群桩基础桥梁滞回性能模型试验

发布时间：2018-01-28 10:12

本文关键词： 桥梁工程滞回性能拟静力试验群桩基础承台提离　出处：《中国公路学报》2017年10期 　论文类型：期刊论文

【摘要】：为了研究可提离式群桩基础桥梁的抗震性能,设计和制作了大比例尺的可提离式群桩基础和普通群桩基础单墩桥梁试验模型。试验模型采用细砂土箱模拟桩周土体的约束作用,并对可提离节点进行改进设计,以防止局部破坏。采用位移控制分级往复加载,进行拟静力试验研究,对比2种不同基础桥梁的基本抗震性能。试验结果表明:可提离式桩的桩身损伤要远小于普通桩,改进后的可提离桩的节点未见明显损伤;可提离式群桩基础单墩桥梁模型的滞回曲线呈明显的旗帜形,表明结构主要为非线性弹性变形,而普通桩基础桥梁模型的滞回曲线为典型的梭形,表明结构主要为塑性变形;可提离式群桩基础发生提离后,承台位移由平动为主转为以转动为主,表明提离式基础主要依赖承台以上结构的整体转动来适应水平地震作用,进而减小基础的受力和损伤;可提离式桩基础桥梁的残余位移仅为相应普通桩工况的10%,表明其具有较好的自复位性能;基于割线刚度的刚度退化指标不适宜评估自恢复结构的刚度退化,建议采用重新加载至正常使用极限状态下的最不利荷载组合时的刚度指标。
[Abstract]:In order to study the seismic performance of removable pile group foundation bridge. The test model of a large scale removable pile group foundation and a single pier bridge with ordinary pile group foundation is designed and fabricated. The fine sand box is used to simulate the restraint effect of soil around the pile. The design of detachable joint is improved to prevent local damage. Displacement control is used to control the step reciprocating loading and the pseudostatic test is carried out. The experimental results show that the damage of pile body of removable pile is much smaller than that of ordinary pile, and no obvious damage to the joint of the improved pile can be found. The hysteretic curve of the single pier bridge model of removable pile group foundation is obviously flag-shaped, which indicates that the structure is mainly nonlinear elastic deformation, while the hysteretic curve of the ordinary pile foundation bridge model is typical shuttle shape. It shows that the structure is mainly plastic deformation. After lifting the pile group foundation, the displacement of the pile cap is changed from translational to rotational, which indicates that the lifting foundation mainly depends on the whole rotation of the structure above the cap to adapt to the horizontal earthquake action. And then reduce the stress and damage of the foundation; The residual displacement of the removable pile foundation bridge is only 10 parts of the corresponding normal pile condition, which indicates that the bridge has good self-reset performance. The stiffness degradation index based on Secant stiffness is not suitable to evaluate the stiffness degradation of self-restoring structures.
【作者单位】：同济大学桥梁工程系;
【基金】：国家自然科学基金项目(51378384) 国家重点基础研究发展计划(“九七三”计划)项目(2013CB036302)
【分类号】：U443.15;U446.1
【正文快照】： 0引言“5·12”汶川地震以后,中国对桥梁抗震规范进行了系统修订[1-3],通过引入能力保护的思想完善了延性抗震体系设计。提高了基础的设防要求,对基础部分要求按能力保护原则进行设计,以降低其发生地震破坏的风险。群桩基础具有竖向承载力大、施工方便、场地适应性好等特点,在

【相似文献】