砖砌体结构层数限值及构造柱设置改进

针对现行规范中砖砌体结构层数限值和构造柱设置未考虑楼层内墙体面积差异的问题,提出了楼层墙率指标,通过统计大量砖砌体房屋,分析了不同建造年代和类型砖砌体房屋楼层墙率,根据结构抗震评估理论及判别准则,分析了楼层墙率对层数限值和构造柱设置的影响,提出了不同性能目标下层数限值和构造柱设置建议.分析结果表明:为满足大震不倒的要求,在砌体结构承重方向,对设防烈度7度的7层房屋,装配式楼(屋)盖的楼层墙率应不小于5.5%,现浇楼屋盖的楼层墙率应不小于4.5%;对设防烈度8度的6层房屋,装配式楼(屋)盖楼层墙率应不小于6.5%,现浇楼屋盖的楼层墙率应不小于5.5%;对设防烈度9度的4层房屋,装配式楼(屋)盖的楼层墙率应不小于6.5%,现浇楼屋盖的楼层墙率应不小于5.5%. 

Improvement Measures for Layer Limits and Tie Column Settings in Masonry Structures

In order to make up for some deficiencies in layer limits and tie column settings for brick masonry structures in seismic design code, where the provisions of layer limits and tie column settings are presented without considering the difference in wall area on a floor, an index of the ratio of wall areas in load-bearing direction to the floor areas (RWF) was proposed. Some differences in RWF due to different types and construction ages were studied by a statistical analysis of a lot of design data. In addition, according to the seismic evaluation theory and its judgment standard, the influences of RWF on layer limit and tie column setting were analyzed. Some suitable measures of layer limits in different performance target and structural columns settings were also suggested. The analysis results show that, in order to meet the requirement of a structure does not collapse in a major earthquake, the RWF of a seven-storey brick masonry structure with assembled slabs subjected to seismic fortification intensity of 7 degree shall not be less than 5.5%, and the RWF of the structure with cast-in-situ slabs shall not be less than 4.5%; the RWF of a six-storey structure with assembled slabs subjected to seismic fortification intensity of 8 degree shall not be less than 6.5%, and the RWF of the structure with cast-in-situ slabs shall not be less than 5.5%; the RWF of a four-storey structure with assembled slabs subjected to seismic fortification intensity of 9 degree shall not be less than 6.5%, and the RWF of the structure with cast-in-situ slabs shall not be less than 5.5%.