任意截面双向偏心受压构件极限承载力计算方法  

Calculation Method of Ultimate Bearing Capacity of Members with Arbitrary Cross Section Subjected to Biaxial Eccentric Compression

作　　者：李波[1,2,3] LI Bo(China Railway Siyuan Survey and Design Group Co.,Ltd.,Wuhan 430063,China;China Railway Construction Bridge Design and Research Branch,Wuhan 430063,China;Hubei Provincial Engineering Research Center of Rail Transit Smart Bridge Technology,Wuhan 430063,China)

机构地区：[1]中铁第四勘察设计院集团有限公司,武汉430063 [2]中铁建大桥设计研究院,武汉430063 [3]轨道交通智慧桥梁技术湖北省工程研究中心,武汉430063

出　　处：《铁道标准设计》2020年第S01期90-93,98,共5页Railway Standard Design

基　　金：中铁第四勘察设计院集团有限公司科技研发项目(2019D003,2020D003)。

摘　　要：Q/CR 9300-2018《铁路桥涵设计规范(极限状态法)》已正式颁布实施,桥梁构件计算方法从"容许应力法"向"极限状态法"转变。为找到一种适用于任意截面形式的双向偏心受压构件极限承载力计算方法,基于平截面和理想弹塑性模型假定,通过对截面应力-应变关系及受力平衡方程进行深入分析,推导出钢筋混凝土截面弹塑性受力数值积分算法。基于该方法,保持初始荷载偏心距不变,采用二分法对轴力进行迭代计算,以混凝土或钢筋达到极限应变为收敛条件,编制计算机程序,求解出构件极限承载力。通过实例对比分析表明,该计算方法正确,程序计算结果可靠,满足工程设计要求。Code for Design of Railway Bridge and Culvert(Limit State Method)Q/CR 9300—2018 has been officially promulgated,and bridge structure design is changing from"allowable Stress Method"to"Limit State Method".In order to find a method of calculating the ultimate bearing capacity applicable for arbitrary cross sections subjected to biaxial eccentric compression,a general numerical integration algorithm of reinforced concrete section subjected to elastic-plastic force is derived by analyzing stress-strain relationship and force balance equation based on plane section and elastic perfectly plastic assumption.With this method,the axial force is calculated iteratively by dichotomy method with the initial load eccentric distance maintained unchanged.Taking the ultimate strain of concrete or reinforcement as the convergence condition,the ultimate bearing capacity of the member could be obtained.The results show that the method is correct,the calculation result is reliable,and the requirements of engineering design are satisfied.

关 键 词：铁路桥涵设计 极限状态法 任意截面 双向偏心受压 极限承载力 数值积分 弹塑性 

分 类 号：U441[建筑科学—桥梁与隧道工程] U448.13[交通运输工程—道路与铁道工程]