简支组合梁收缩徐变效应的精确与近似计算方法  

Precise and Approximate Methods to Calculate Shrinkage and Creep Effects of Simply-Supported Composite Beam

作　　者：周东华[1] 韩春秀[1,2] 杨天元[1] 杨应恩 王永爽[1] 

机构地区：[1]昆明理工大学土木工程学院,云南昆明650504 [2]昆明冶金高等专科学校建工学院,云南昆明650033

出　　处：《西南交通大学学报》2015年第6期1018-1024,共7页Journal of Southwest Jiaotong University

基　　金：国家自然科学基金资助项目(51268022;51468026)

摘　　要：为提供一种简便、可行的计算方法,基于迪辛格法,分别按精确和近似方法推导、求解组合梁徐变和收缩效应的微分方程组.精确方法须求解耦合微分方程组,求解困难,解析解冗长,不便运用;近似方法忽略了混凝土板中重分布弯矩对轴向应变的影响,可实现微分方程组解耦,求解方便.计算结果表明:当混凝土板与钢梁的刚度比小于0.2时,两者的计算误差很小,在2%以内.钢梁刚度越大,对混凝土板徐变的约束越大,重分布内力也越大;钢梁中存在一个特殊的徐变应力零点.To provide a simple and feasible calculation method,differential equations for composite beam with creep and shrinkage were derived and solved based on the Dischinger＇s method by using exact and approximate methods respectively. When the exact method is adopted, the coupled differential equations need to be solved,the solution is difficult to acquire and too complex to apply.When the approximate method is used,the effect of moment redistribution in concrete slab on axial strain is neglected, this makes the differential equations decoupled and easy for solving. The calculation results of the two methods have a good agreement in the case of the rigidity ratio of concrete slab to steel beam being smaller than 0. 2,and the error is within 2%. The larger the rigidity of steel beam,the larger the creep restrain to concrete slab and the redistribution internal forces. Furthermore,a special creep stress zero point exists in the section of steel beam.

关 键 词：简支组合梁 收缩与徐变 约束徐变 内力重分布 徐变应力零点 

分 类 号：TU398[建筑科学—结构工程]