强震作用下超高桥墩动力稳定性理论研究  

Theoretical Study on the Dynamic Stability of Super-high Bridge Piers under Strong Earthquakes

作　　者：程麦理 李青宁[2] 苗如松 

机构地区：[1]延安大学建筑工程学院,陕西延安716000 [2]西安建筑科技大学土木工程学院,陕西西安710055

出　　处：《地震工程学报》2016年第3期360-365,共6页China Earthquake Engineering Journal

基　　金：国家自然科学基金项目(51078306);国家青年基金项目(51408453);高等学校博士学科点专项科研基金(20106120110004);陕西省自然科学基础研究计划资助项目(2013JQ7007)

摘　　要：根据平截面假定,考虑超高桥墩大位移变形产生的几何非线性影响,建立超高桥墩的振动控制微分方程,利用变步长的龙格-库塔法进行求解,结合B-R运动判定准则,对超高桥墩在地震作用下的动力失稳机理进行研究。理论分析表明,超高桥墩的动力失稳与桥墩的几何尺寸、质量分布、边界条件有密切关系;桥墩动力失稳时刻随地震波加速度峰值的增大而减小;失稳时刻与失稳加速度荷载有对应关系。算例结果表明:本文方法正确,利用本文理论能够准确计算超高桥墩的失稳时刻及失稳加速度,对超高桥墩动力失稳的理论分析及工程实践有重要指导意义。With the steady progress of transportation infrastructure construction in China,a large number of bridges with high piers have been built in the mountainous southwest region,a part of the Alpine-Himalayan seismic belt where earthquakes are frequent.Thus,research on structural seismic response has always attracted close attention.In this paper,we study the dynamic instabil-ity mechanism,seismic response,and performance of super-high bridge piers,develop reasonable structural strategies,and suggest design proposals to avoid dynamic instability.Assuming a plane section and considering the geometric non-linear effect induced by large displacement deformation of super-high piers,a numerical model of super-high piers is established.The governing differenti-al equations of super-high piers are established,and a displacement shape function is proposed ac-cording to the force-deformation constitutive law of members.The Runge-Kutta method is used to solve the equation.Based on the B-R kinematic criterion,the dynamic instability mechanisms of super-high piers are discussed.The results from the numerical model under the dynamic condi-tions of various seismic waves are discussed,and longitudinal and lateral displacement at the top of high piers is studied.Theoretical analysis and calculation results show that the dynamic insta-bility of super-high piers is closely related to pier geometry,mass distribution,and boundary con-ditions.The dynamic instability time of piers decreases with an increase in the peak acceleration of seismic waves.The relationship between the acceleration load and instability time shows strict cor-relation.The results from the example show that the method in this paper is simple,feasible,and correct.Using the theory in this paper,the dynamic instability time and acceleration load critical value of super-high piers can be calculated accurately.The theory is therefore significant in theo-retical analysis and engineering practice regarding the dynamic instability of super-high piers.

关 键 词：强震作用 超高桥墩 动力稳定性 位移形函数 龙格-库塔法 

分 类 号：TU997[建筑科学—市政工程]