考虑水作用的桥墩自振特性计算方法对比分析  

Comparison of methods for natural frequency calculation of piers considering interaction with water

作　　者：杨吉新[1] 党慧慧[1] 雷凡[1] 

机构地区：[1]武汉理工大学交通学院,湖北武汉430063

出　　处：《世界地震工程》2010年第3期91-95,共5页World Earthquake Engineering

基　　金：国家高技术研究发展计划(863)项目(2007AA11Z107)

摘　　要：地震作用下,深水中的桥墩在水流作用下动力特性会有很大的变化,《铁路工程抗震设计规范》(GB50111-2006)规定:在常水位以下的部分,对水深超过5m时,应计入地震动水压力对桥墩的影响。考虑水的作用,目前可以用于计算桥墩自振频率和周期的方法主要有解析法、数值分析法和规范中给出的公式法,文中对这3种方法做了简单的介绍,并通过对某连续钢构桥桥墩的周期和自振频率的计算,综合其他各个方面对这3种方法进行进一步对比分析。总结得出了这3种方法分别适用的范围:公式法可用于只需1阶频率、不用考虑地基土影响的圆形或圆端形桥墩;解析法则适用于结构形式简单,截面统一的桥墩;数值分析法可以用于所有形式的桥墩,灵活性强,但对建模能力要求较高。在此基础上对这3种方法的优缺点进行了分析,为考虑与水相互作用的桥墩自振特性计算方法的选择提供了参考依据。Owing to the interaction of pier and water,the dynamic characteristics of pier in water have great change.Code for Seismic Design of Railway Engineering（GB50111-2006） prescribes that if the normal water level is deeper than 5 meters,the dynamic water pressure on piers should be considered.For calculating natural frequency and period of the pier in deep water,the available methods include analytic method,numerical method and the formula given in the Code.There is a short introduction of the 3 methods.The natural frequency of piers of a rigid frame bridge project is calculated.The results are found that the Code formula is suitable only for fundamental frequency calculation,and no considering the earth base effect of circle section shape piers.The analytic method is suitable for the piers with simple shape and constant section.The numerical method applies to all types of piers,but requires high techniques in creating calculation model.Based on the above relative merits of the three methods,the results can be for a reference of the method selection in calculating the dynamic characteristics of piers.

关 键 词：动力特性 基本周期 自振频率 动水压力 

分 类 号：U443.22[建筑科学—桥梁与隧道工程] P315.95[交通运输工程—道路与铁道工程]