外套钢筋混凝土墙的多层砌体结构抗震性能分析

Seismic analysis of multi-story masonry structure parceled with reinforced concrete wall

砌体结构房屋在我国应用广泛,早期建造的多层砌体结构住宅多未考虑抗震设防,在汶川地震中这类房屋存在严重的震害,如何通过合理的结构加固实现对这些已有建筑的综合改造值得研究。介绍6层砌体结构住宅实施综合平改坡加层改造的工程实例,原结构的竖向承载能力可满足加层要求,但结构的抗震能力存在不足,为此采用在原砌体结构的南北外侧新增钢筋混凝土墙的结构加层加固方法。采用PKPM系列软件进行了小震作用下的结构强度分析,并得到了刚度凝聚层模型的主要分析参数,利用SAP2000软件建立了钢筋混凝土-砌体层模型进行大震作用下的弹塑性分析,结果表明地震作用主要由新加的钢筋混凝土墙承担,结构的抗震性能明显改善,具有大震不倒的抗震能力。

Masonry structures are widely used in our country.Early masonry residential buildings have some defects in seismic performances since seismic codes were not issued when they were constructed.These kinds of masonry buildings have severe damages in the massive Wenchuan Earthquake.The comprehensive transformation of these buildings by reasonable structural retrofit techniques is worthy of study.An engineering case of adding storey and slope roof on a 6 storey masonry building with structural retrofit is introduced in this paper.The vertical capacity satisfies the static strength demand of adding storey,but the poor seismic capacity should be strengthened.Reinforced concrete walls are added outside,both the north and the south of the original masonry structure.Analytical models are established by the PKPM software for the strength check under minor earthquakes and the key parameters of the lumped storey model.The SAP2000 software is used for elasto-plastic analysis of the lumped storey model under major earthquakes.The seismic performance of the strengthened structure is greatly improved as most of the earthquake action is taken by the parceled reinforced concrete walls.The demand of no collapse under major earthquake is guaranteed.