罕遇与设防烈度地震作用下规则多层砌体结构的抗震计算实用方法

以砌体平均抗剪强度公式和理想弹塑性模型为基础,建立了砌体结构楼层屈服强度系数的计算公式,同时考虑了抗震措施的影响,实现了单片墙肢设计强度计算向楼层屈服强度计算的转换。根据Dwairi等提出的以窄Takeda滞回模型为基础的有效阻尼计算公式,并考虑砌体结构的基本周期和延性特征对其进行适当简化,建立了采用结构整体位移延性系数表达的砌体结构阻尼折减系数公式。根据剪切型薄弱层屈服机制的特征,建立了砌体结构层间位移延性系数与整体位移延性系数的关系。据此,可根据不同性能目标和抗震措施下的层间位移延性系数直接计算阻尼折减系数。通过楼层屈服强度系数与阻尼折减系数的比较,实现罕遇地震与设防烈度地震作用下规则多层砌体结构的抗震计算。分析表明,所提方法简便实用,分析结果合理可靠,可用于基于性能的规则多层砌体结构抗震分析。

Practical method of seismic calculation of regular multi-storey masonry structures under rare and fortification earthquake

Calculation formula of storey yield strength coefficient of masonry structures was established based on the formula of average shear strength and ideal elastic-plastic model. Considering the influence of various seismic measures, the calculation method of storey yield strength of mansory structures was established, the calculation of design strength of monolithic wall limb was converted to the calculation of storey yield strength. According to the formula of effective damping based on the narrow Takeda hysteresis model raised by Dwairi etc. and further simplification of the formula based on the fundamental period and ductility characteristics of masonry structure, the damping reduction coefficient formula expressed by the whole structural displacement ductility coefficient was established. According to the characteristics of yield mechanism of shear weak layer, the relationship between the storey displacement ductility coefficient and the structure displacement ductility coefficient was established. Then the damping reduction coefficient could be calculated based on the allowable value of the storey displacement ductility coefficient under the different performance objectives and seismic measures. Finally, the seismic calculation of regular multi-storey masonry structures under rare earthquake and fortification arthquake was realized by comparing the storey yield strength coefficient with the damping reduction coefficient. The analysis shows that the method is simple and practical and the analysis results are reasonable and reliable. The proposed method can be used for the performance-based seismic analysis of regular multi-storey masonry structure.