桥梁高桩承台体系推倒分析侧向力分布模式

Lateral Load Pattern Study of Pushover Analysis for Elevated Pile Foundation System of Bridges

摘要:

介绍了几种常见的侧向力分布模式,并针对高桩承台体系的等效固结模型,通过改变承台质量,对几种分布模式的推倒分析曲线与非线性时程分析结果进行了比较.发现承台质量较大时,上述模式均低估了承台的惯性力作用,并且时程分析得到的体系抵抗不同地震波的能力差异较大,而上述模式对应的能力曲线却没有体现出这种不同.考虑到高桩承台体系承台惯性力较大的特点,借鉴墩顶集中力分布模式,提出了双集中力分布模式.以一飘浮体系斜拉桥的高桩承台模型为例,进行常见模式以及新模式下纵桥向的推倒分析,并将推倒分析曲线与非线性时程分析的结果进行了比

Abstract:

Common lateral load patterns are introduced and the cap mass is changed in an attempt to study the equivalent fixing model of elevated pile foundation system.A comparison between pushover curves of these load patterns and results of nonlinear time history analysis is made.The result shows that,when cap mass is relatively large,cap inertial force is underestimated by using the above load patterns and through time history analysis,discrepancy of seismic capacity system against different earthquake waves is distinct,while capacity curves of the above patterns can't tell the difference.Given the cap inertial force of elevated pile foundation system is relatively great,double forces pattern is developed based on top single force pattern.At last,with the elevated pile foundation model of a floating type cable-stayed bridge,pushover analysis with common patterns and new pattern on longitudinal direction is made,then compared with nonlinear time history analysis.The result shows the new pattern works well.