墩高渐变的多联桥梁下部结构抗震配筋设计方法研究

Research on Seismic Reinforcement Design Method for Substructure of Multi-Span Bridges with Gradual Pier Heights

摘要:

为研究上下部结构形式一致、墩高渐变的多联桥梁在地震作用下的内力响应特点及规律，从而优化结构的抗震设计，本文以唐山某座城市桥梁为例，借助Midas Civil以该工程为参考建立三维有限元模型进行抗震计算，重点归纳探讨了高墩和矮墩的优势和劣势。为充分发挥不同高度桥墩的优势，提出了一种设计思路：先定义临界墩高，并以此划分高墩和矮墩，在E2地震下允许高墩进入塑性、矮墩保持弹性。按此思路对案例工程进行计算和配筋设计。研究结果表明，该设计思路具有较高的实用性，可有效减少配筋量和计算工作量，兼顾结构的安全性和经济性，为类似多联桥梁抗震设计提供了一种可行的参考思路。

Abstract:

To investigate the internal force response characteristics and patterns of multi-span bridges with consistent upper-lower structural forms and gradually varying pier heights under seismic action, thereby optimizing structural seismic design, this paper takes an urban bridge in Tangshan as a case study. A three-dimensional finite element model of Midas Civil was established based on the project for seismic calculations, with particular focus on analyzing the advantages and disadvantages of tall and short piers. To fully utilize the strengths of piers with different heights, a design approach was proposed: first defining critical pier height to categorize tall and short piers, allowing tall piers to enter plasticity while maintaining short piers elastic under E2 seismic conditions. This design concept was applied to calculate and design reinforcement for the case project. The results demonstrate that this design method exhibits high practicality, effectively reducing reinforcement quantities and computational workload while balancing structural safety and economic efficiency. It provides a feasible reference approach for seismic design of similar multi-span bridges.