南京长江大桥桥头堡填充墙加固方法比较

Comparison of Strengthened Methods for Bridgehead of Nanjing Yangtze River Bridge Infilled Walls

为研究南京长江大桥桥头堡填充墙特殊加固方法的加固效果,首先,选取桥头堡典型尺寸的非整墙加固进行有限元分析,并与整墙加固进行比较;然后,针对不同加固区高度进行参数分析,研究加固区高度对填充墙的抗震性能的影响;最后,给出不同加固区高度的非整墙加固的抗震承载力及刚度增强系数的计算公式.研究结果表明:南京长江大桥桥头堡非整墙加固相比于整墙加固虽效果有所下降,但依然有效;加固区高度基本为整墙高度的74%,其抗震承载力提高293%~335%,刚度增强系数为1.891~1.935,均大于规范值;加固墙的高宽比对加固效果也有影响,但是对刚度增强系数影响略小,而且不同高宽比加固填充墙在地震时中部裂缝的方向存在明显差异;随着加固区高度减小,填充墙面层加固效果明显降低,而且可能导致未加固区域墙首先开裂,故建议非整墙加固区域高度要超过整墙高度的74%.

In order to study the effect of special reinforcement method used in the infilled walls of the bridgehead of Nanjing Yangtze River Bridge,non whole wall reinforcement method of typical bridgehead size was analyzed by finite element method,comparing with whole wall reinforcement method.Based on the parameter analysis of different reinforcement heights,the influence of reinforcement heights on the seismic performance of infilled wall were studied.The formulas to compute the shear capacity and the stiffness enhancement factor of the infilled walls with different reinforcement heights were presented.The results show:although the effect of non whole wall method is not as good as the effect of whole wall method,it′s still effective generally.When height of reinforcement is 74%of whole wall height,the shear capacity is improved by 293%335%,and the stiffness enhancement factor(SEF)is 1.8911.935,which both exceed the value suggested by the code.The reinforcement effect is also influenced by the height to width ratios of the infilled walls,but the stiffness enhancement factor is less influenced,and crack direction of reinforcement infilled wall in the earthquake is influenced significantly by the height to width ratio.The reinforcement effect of infilled walls reduces dramatically as reinforcement height decreases,and the wall without reinforcement may cracks firstly.Therefore,it is suggested that the reinforcement height should exceed 74%height of the whole wall.