铁路圆端形空心墩位移能力与等效塑性铰长度分析

Analysis of displacement capacity and equivalent plastic hinge length of hollow piers with rounded rectangular cross section in railways

为采用简化公式计算桥墩的位移能力,大多数国家的桥梁抗震规范均已引入等效塑性铰长度这一概念。由于铁路桥墩粗大等特点,目前我国铁路规范尚未给出桥墩等效塑性铰长度的计算公式。针对影响等效塑性铰长度的3个主要因素:墩高、配筋率和截面宽度,采用基于OpenSees平台的纤维单元,对72个桥墩进行横桥向推覆数值模拟,计算得到等效塑性铰长度,通过回归分析给出适合此类桥墩的等效塑性铰长度计算公式,并基于所得到的等效塑性铰长度,利用简化公式计算桥墩的位移能力。研究结果表明:基于本文所提出的等效塑性铰长度计算公式能较好地与有限元计算结果相吻合。

In order to calculate the displacement capacity of bridge piers using a simplified formula,the concept of equivalent plastic hinge length has been introduced in bridge seismic codes in most countries.However,due to the characteristics of large railway piers,code for seismic design of railway engineering in China has no recommendations for the equivalent plastic hinge length.Based on the three main factors affecting the equivalent plastic hinge length:pier height,reinforcement ratio and cross-sectional width,the transverse static pushover numerical simulation of 72 railway hollow piers with rounded rectangular cross section was carried out utilizing the fiber element based on OpenSees platform,and the equivalent plastic hinge length was calculated,in order to give a suitable formula for calculating the equivalent plastic hinge length for such piers by regression analysis,based on the obtained equivalent plastic hinge length,the displacement capacity of the pier was calculated by using the simplified formula.The results show that the formula based on the equivalent plastic hinge length proposed in this paper can be well matched with the finite element calculation results.