考虑双向水平循环加载对混凝土筒体性能影响的试验研究

Experimental Study on the Effects of Biaxial Cyclic Loadings on the Behavior of Concrete Core Walls

为了研究混凝土核心筒的抗震性能,采用相同的2个高宽比为3.14、设计轴压比为0.4的混凝土核心筒大型试件进行了水平单向和双向拟静力试验,研究了双向加载对于核心筒的破坏形态、承载能力、变形性能、刚度退化、滞回耗能等方面的影响.结果表明:试件在水平单向和双向反复加载下的最终破坏形态均为底部钢筋受拉屈服后混凝土压溃的整体弯曲破坏.与单向加载相比,双向加载的影响使筒体的承载力和极限变形能力明显降低,刚度退化加剧;双向加载时筒体耗能较大是由墙肢底部关键区域提前破损和失效所致,而连梁转动耗能小于单向加载时的耗能.

To study the seismic behavior of concrete core walls, two large size specimens of concrete core wall with aspect ratio of 3. 14 and axial load ratio of 0.4 were tested, horizontally applied to uniaxial and biaxial pseudo-static loadings, respectively, to investigate the effects of biaxial cyclic loadings on their failure pattern,load-carrying capacity, deformation ability, stiffness degradation, energy dissipation, etc. It shows that both specimens fail in flexure at the bottom of the wall; compared to the ease of uniaxial cyclic loadings, the effects of biaxial loadings result in significant decrease of load-carrying capacity and deformation ability, and faster stiffness degradation. The increase of energy dissipation with biaxial loadings as compared to that with uniaxial loadings is mainly due to the early damage and failure of the bottem of the wall, and the energy dissipated from plastic hinges of coupling beams in the case of biaxial loadings is less than the latter.