考虑邻跨混凝土徐变收缩差异的连续组合梁次内力分析  

Analysis of secondary internal forces of continuous composite beams considering difference of creep and shrinkage of concrete in adjacent span

作　　者：韩春秀 HAN Chunxiu(Department of Physics and Civil Engineering,Yunnan Minzu University,Kunming 650504,China)

机构地区：[1]云南民族大学物理与土木工程系,云南昆明650504

出　　处：《大连理工大学学报》2023年第6期637-645,共9页Journal of Dalian University of Technology

基　　金：国家自然科学基金资助项目(52068068,51708486).

摘　　要：为预估徐变收缩对连续组合梁长期服役期间的潜在影响,考虑两跨连续组合梁邻跨混凝土徐变收缩特性、跨度和荷载互异等情况,基于力法基本原理和混凝土徐变本构方程,对徐变收缩次内力进行分析.结果表明:不考虑收缩影响时,两跨连续组合梁邻跨混凝土徐变特性或跨度相同,中间支座徐变次弯矩为零;邻跨徐变特性和跨度均不同,或邻跨徐变特性和加载方式均不同,中间支座产生随时间变化的徐变次弯矩.考虑收缩影响时,所有工况均产生收缩次弯矩.支座次弯矩的变化程度与两跨的徐变系数差、老化系数差、跨度差、荷载差等因素相关,内力的重新分布从两跨中徐变大的一侧向徐变小的一侧转移,两跨的徐变特性差异越大,重分布值越高,徐变次弯矩越大;反之越小,当两跨的徐变特性差异趋于最小,支座徐变次内力趋于零.支座次弯矩大小受截面内部应力重分布影响,与混凝土徐变系数和老化系数及重分配系数相关.采用所提分析方法可对连续组合梁受截面内和结构外双重耦合的内力进行解析,公式的参数可编制成表格,便于工程应用.To predict possible impacts of creep and shrinkage on continuous composite beams during long-term service,the analysis is conducted for the secondary internal forces of creep and shrinkage based on the basic principle of force method and the creep constitutive equation of concrete,considering different status of creep and shrinkage characteristics of concrete in adjacent span,span and load of two-span continuous composite beams.The results show that,without considering shrinkage effect,the secondary bending moment of creep at the middle support is 0 when the creep characteristics of concrete or span of the adjacent span of the two-span continuous composite beams is the same.And the secondary bending moment of creep varies with time when the creep characteristics and span of the adjacent span are different,or the creep characteristics of the adjacent span and loading methods are different.When the shrinkage effect is taken into account,the secondary bending moments of shrinkage are generated in all cases.The change degree of the secondary bending moment of the support is related to the difference of creep coefficient,the difference of aging coefficient,span difference and load difference of the two spans.The redistribution of internal force shifts from the side with greater creep to the side with smaller creep.The greater the difference of creep characteristics between the two spans,the higher the redistribution value and the greater the secondary bending moment of creep.And vice versa,when the difference of creep characteristics between the two spans tends to be minimal,the creep secondary internal force of the support tends to be 0.The secondary bending moment of the support is affected by the stress redistribution inside the section,and is related to the creep coefficient and aging coefficient of concrete and redistribution coefficient.The proposed analytic method can be used to analyze the internal forces of the continuous composite beam under the dual coupling of the section and the structure,and the paramete

关 键 词：徐变 收缩 连续组合梁 次内力 

分 类 号：TU398[建筑科学—结构工程]