单体建筑无筋砌体加固体系的抗震韧性研究

Seismic resilience of the reinforcement system of unreinforced masonry in an individual building

摘要:

单体建筑无筋砌体结构的抗震韧性较差,在地震中容易发生严重破坏和倒塌。为此,以抗震韧性为参数指标,对单体无筋砌体结构进行加固并分析,研究其在地震作用下的抗震能力。以某实际工程作为研究对象,运用ANSYS软件建立单体建筑无筋砌体加固有限元模型,选取中国汶川地震波、日本阪神大地震波、美国克恩县地震波、中国台湾集集地震波及人工地震波作为地震动输入,利用韧性指数法和韧性等级法,从无筋砌体加固体系在震后的修复费用、修复时间及人员伤亡等方面进行分析,得到抗震韧性评估结果。研究表明:(1)在罕遇地震、设防地震和多遇地震的情况下,单体建筑无筋砌体结构的层间位移、层间剪应力、破坏程度均大于单体建筑无筋砌体加固体系;(2)在受到地震强弱因素影响下,无筋砌体结构的抗震韧性指数最高为0.877,而其加固体系的抗震韧性指数最低为0.908;(3)在经历不同地震波后,无筋砌体结构受到较大损害等级占比较高,人员伤亡较重,需要花费较长的时间和较多的费用完成灾后重建;而经过加固后的无筋砌体结构,加固体系受到较小损害等级占比较高,人员伤亡较轻,且能够用较短的时间和较少的费用完成灾后重建。

Abstract:

An unreinforced masonry structure is prone to severe damage and collapse during earthquakes because of its poor seismic resilience. In this study, seismic resilience was used as a parameter index for analyzing the seismic capacity of the reinforcement of an unreinforced masonry structure. A finite element model for the unreinforced masonry structure in buildings was established using the software ANSYS. The input waves were the Wenchuan earthquake wave, the Hanshin earthquake wave in Japan, the Kern earthquake wave in the United States, the Chi-Chi earthquake wave in Taiwan, China, and an artificial earthquake wave. Resilience index and resilience grade were used in evaluating the seismic resilience of an unreinforced masonry reinforcement system in terms of repair cost, repair time, and personnel casualties after an earthquake. Results indicate that (1) the inter-story displacement, inter-story shear stress, and extent of damage in the unreinforced masonry structure are greater than those of the unreinforced masonry with reinforcement system during rare, fortification, and frequent earthquakes; (2) the maximum seismic resilience index of the reinforced masonry structure is 0.877, and the minimum seismic resilience index of the unreinforced masonry with reinforcement system is 0.908 at different earthquake intensities; (3) the unreinforced masonry structure suffer from severe damage levels and heavy casualties and needs long time and high costs for post-disaster reconstruction when different seismic waves are inputted. By contrast, the unreinforced masonry structure with a reinforcement system has a high proportion of minor damage and few casualties and can be reconstructed in a short time with low costs.