双向地震作用下砌块整浇墙受力机理与抗震性能研究

Fully grouted reinforced-block masonry shear wall (FG-RMSW) structure is a novel structural system. FG-RMSW is based on RMSW structure, but it is different from RMSW in porosity rate, building method, the reinforcement method, and so on, which makes mechanical property different. Currently FG-RMSW has been little investigated, so there will be great theoretical significance and the engineering application value if the dynamic properties and seismic performance of this type of structural system could be revealed. This project will investigate the effect of the ground motion direction, aspect ratio and the applied axial compressive stress on the seismic performance of such walls, according to tests of the full-scale T-type FG-RMSWs subjected to the low cyclic reversed lateral load or the shaking table. The mechanical properties, damage modes and failure mechanisms will be revealed. The module of materials on fully grouted block masonry will be exploited, and then the mathematical formula for estimating the bi-directional shear bearing capacity will be obtained. The skeleton curve model will be extracted according to the test records, meanwhile, the load-displacement restoring force model will be proposed, and the seismic design method and construction measure will be provided. The project will further modify the seismic design theory of FG-RMSW, and also provide the theoretical foundation and technological support for revising the provisions in the seismic design codes or masonry structures design code.

砌块整浇墙结构是一种新型的结构体系，它是在配筋砌块砌体剪力墙结构基础上发展起来的，二者在对孔率、组砌方法、配筋方式等方面均有较大变化，势必导致二者的力学性能存在较大差别。目前，此种体系的研究仍处于初级阶段，了解其动力特性和抗震能力，具有重要的理论意义和工程应用价值。本项目以T型砌块整浇墙为研究对象，通过足尺砌块整浇墙在双向地震作用下的拟静力试验、振动台试验及精细化有限元分析，探讨地震作用方向、剪跨比、竖向压应力等参数对墙体抗震性能的影响规律，揭示此种墙体的受力性能、破坏模式和失效机理。开发全灌芯砌块砌体的材料模块，建立砌块整浇墙的双向受剪承载力计算公式。利用试验数据确定骨架曲线模型，给出双向地震作用下的荷载-位移恢复力模型，提出抗震设计方法和构造措施。本项目的研究成果将进一步完善砌块整浇墙的抗震设计理论，为建筑抗震设计规范和砌体结构设计规范的修订提供理论依据和技术支持。

针对在多次地震中纵横墙交接处常常破坏的现状，以T型砌块整浇墙在双向荷载作用下的拟静力试验、振动台试验为切入点，揭示双向荷载作用下砌块整浇墙的受力性能、破坏模式和失效机理，实现材料层面滞回本构关系和构件层面滞回抗震性能的精细化数值模拟分析。系统研究竖向压力、水平、竖向配筋率等参数对砌块整浇墙抗震性能的影响。分析墙体刚度衰减规律，计算墙体的耗能能力，得到耗能-位移关系曲线，给出墙体在特征点处的耗能比和等效粘滞阻尼比。通过荷载-位移滞回曲线，分析了墙体破坏过程，探讨墙体的强度变化趋势，提出了抗震设计方法。通过对砌块整浇墙受力状态分析，给出广义应变能密度和值-荷载关系曲线，应用相关性准则判定剪力墙受力状态的跳跃特征点，揭示并验证了剪力墙滞回受力状态跳跃特征，确定了墙体滞回受力状态的弹塑性分支点荷载。进行了双向地震作用下足尺砌块整浇墙的振动台试验研究，得到了地震作用方向对砌块整浇墙双向抗震性能的影响，对模态进行分析，得到墙体动力特性变化趋势，进行了动力响应分析，得到了不同强度下、不同作用方向下，墙体的加速度时程曲线、位移时程曲线、最大绝对位移、最大相对位移、最大加速度等参数。完善双向地震作用下砌块整浇墙的抗震分析手段，为建筑抗震设计规范和砌体结构设计规范的进一步修订提供理论依据和试验基础。