A study on Residual Drift and Concrete Strains in Unbonded Post-Tensioned Precast Rocking Walls
A study on Residual Drift and Concrete Strains in Unbonded Post-Tensioned Precast Rocking Walls
复制标题
DOI：
--
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Sumedha Sharma;Sriram Aaleti
中科院分区：
文献类型：
--
作者：
Sumedha Sharma;Sriram Aaleti
现代抗震设计一直专注于开发具有成本效益的结构系统，这些系统在地震期间遭受最小的破坏。无粘结后张预制混凝土墙提供了一个合适的解决方案，因为它们的自定心行为和承受大的非线性变形的能力，以最小的损害。在过去的二十年里，人们对无粘结后张预制墙的抗侧力性能进行了大量的试验和分析研究。这些调查主要集中在横向承载力，自定心能力，能量耗散和损伤程度的限制混凝土区域的墙系统。过去的实验结果表明，墙系统的自定心能力降低在较高的横向漂移。特别是耗能能力较大的摇摆墙，其残余位移较大。墙系统中的这种残余位移可能会影响整个结构重新居中的能力。虽然增加初始预应力有助于减少残余位移，但它也会使混凝土承受更大的轴向压应力，这可能导致摇摆角处约束混凝土的强度过早退化。在这种墙系统的设计中，准确预测在增加的漂移周期期间受限区域中的预期混凝土应变是至关重要的。文献中的简化设计程序假定塑性铰长度的不同值，以估计临界混凝土应变值。从文献中的实验测试的结果进行了分析，以了解残余位移的能量耗散元件的影响，并检查预测临界混凝土应变的简化设计程序的准确性。根据试验结果，对无粘结后张预制摇摆墙的耗能构件和塑性铰长度的设计提出了建议。
Modern seismic resistant design has been focusing on development of cost effective structural systems which experience minimal damage during an earthquake. Unbonded post-tensioned precast concrete walls provide a suitable solution due to their self-centering behavior and their ability to undergo large nonlinear deformation with minimal damage. Several experimental and analytical investigation focusing on lateral load resisting behavior of unbonded post-tensioned precast walls has been carried out in the past two decades. These investigations have primarily focused on lateral load resistance, self-centering capacity, energy dissipation and extent of damage in confined concrete region of the wall system. Past experimental results have shown that self-centering capacity of the wall system decreases at higher lateral drifts. Particularly, rocking walls with higher energy dissipation capacity, sustain considerable residual displacement. This residual displacement in the wall system may affect the ability of the entire structure to re-center. Though increasing initial prestressing force helps in reducing residual drift, it also subjects concrete to increased axial compressive stress which may lead to premature strength degradation of confined concrete in rocking corners. Accurate prediction of expected concrete strains in confined regions during increasing drift cycle is critical in design of such wall systems. Simplified design procedures available in literature assume different values for plastic hinge length to estimate critical concrete strain values. The results from the experimental tests available in literature were analyzed, to understand the effects of energy dissipating elements on residual drift and to examine the accuracy of simplified design procedures in predicting critical concrete strain. Based on the findings, recommendations are made on design of energy dissipating elements and plastic hinge length for unbonded post-tensioned precast rocking walls.