剪力墙结构置换加固应力重分布

为深入揭示无支撑置换混凝土加固过程中剪力墙的受力变化规律,对某剪力墙住宅结构无支撑置换加固施工进行全过程监测。基于ABAQUS有限元分析软件,采用生死单元、等效升温以及添加场变量的方法实现剪力墙施工全过程模拟。结合施工监测数据及有限元模拟结果分析了置换剪力墙及与置换剪力墙相连的梁、楼板受力变化过程; 最后给出了考虑应力重分布后,无支撑分段置换墙体正截面受压承载力计算方法。结果表明:有限元模拟方法能有效模拟混凝土无支撑置换加固施工过程; 由于剪力墙分段拆除和置换,墙体出现了应力重分布现象,且应力重分布程度与墙体分段施工顺序有关; 应力重分布会引起墙体洞口处出现应力集中,但应力集中对加固效果的影响较小,同时还会影响与置换剪力墙相邻的连梁、楼板结构的受力,导致该处应力增加; 建议对剪力墙结构进行无支撑置换加固时,有必要通过分段优化设计和受压承载力复核控制应力重分布的影响。

Stress Redistribution of Shear Wall Structure with Replacement Reinforcement

In order to reveal the stress variation law of shear wall during the reinforcement process of unsupported replacement concrete, the whole process monitoring of a shear wall residential building without support replacement reinforcement was carried out. Based on ABAQUS finite element analysis software, the whole process of shear wall construction was simulated by using life and death element, equivalent temperature rise and field variables. Combined with construction monitoring data and finite element simulation results, the stress change process of replacement shear wall, beam and floor connected with replacement shear wall was analyzed. Finally, the calculation method of the normal section bearing capacity of the unsupported segmental replacement wall was given after considering the stress redistribution. The results show that the finite element simulation method can effectively simulate the construction process of concrete without support replacement reinforcement. Due to the sectional demolition and replacement of shear wall, stress redistribution occurs in the wall, and the degree of stress redistribution is related to the construction sequence of wall segments. Stress redistribution will cause stress concentration at the wall opening, but the stress concentration has little effect on the reinforcement effect. At the same time, it will also affect the stress of coupling beam and floor structure adjacent to the replacement shear wall, resulting in the increase of stress. It is suggested that it is necessary to control the influence of stress redistribution through sectional optimization design and compression bearing capacity recheck when strengthening shear wall structure without support.