混凝土箱梁热—力耦合模型及剪力滞时变效应  

Thermo-mechanics coupling model for concrete box girder and time-dependent effect of shear lags

作　　者：张岗[1] 贺拴海[1] 

机构地区：[1]长安大学交通行业旧桥检测与加固重点实验室,陕西西安710064

出　　处：《解放军理工大学学报（自然科学版）》2010年第2期131-136,共6页Journal of PLA University of Science and Technology(Natural Science Edition)

基　　金：国家自然科学基金资助项目(50908017);交通部西部交通建设科技项目(200531881215);中央高校基本科研业务费专项资金资助项目(CHD2009JC015)

摘　　要：为了研究混凝土箱梁墩顶块翼缘板早期裂缝机理,采用热-力耦合方法,建立了混凝土箱梁水化热温效剪力滞耦合模型,提出了广义剪力滞概念,以混合网格对混凝土箱梁墩顶块进行分层网分。计算了剪力滞随水化热温度荷载变化的全过程,分析了水化热温效剪力滞时变效应规律,并将计算值与试验数据进行了比较。结果表明:水化热温度所产生的剪力滞效应为负剪力滞,其程度与水化热温差峰值相关,降低水化热温差峰值,可有效降低水化热负剪力滞效应;翼缘板边缘拉应力峰值出现的时间滞后于温度峰值时间约40h。因此,水化热—力耦合模型能有效地模拟混凝土箱梁墩顶块水化热剪力滞效应,估计翼缘板拉应力峰值出现的时间,及时采取措施进行控制,防止开裂。Aiming at the earlier temperature crack phenomenon for pier-on mass of concrete box girder during construction based on the actual engineering, the coupling model of hydration heat and shear lag was put forward ,taking the temperature expansion and mini-work principle into consideration. The whole procedure of the shear lag with temperature was computed, the time-dependent effect curve was analyzed, and the time-dependent effect law was studied. The results indicate that negative shear lag effect from hydration heat is related to the peak of its temperature difference, that its negative results may be effectively controlled by the decrease of the temperature difference peak of the hydration heat, and that the occurring time of the tension stress of the hydration temperature heat effect for flange plate is approximate to the occurring time of the temperature difference peak, which is delayed forty hours compared with the occurring time of the temperature peak. Therefore, the calculation results approach to the test value indicate that the coupling model of the hydration heat and shear lag for concrete box girder and test theme is feasible, and that the occurring time of the tensile stress for flange plate is estimated by the occurring time of the temperature peak, in order to adopt effective theme to prevent crack.

关 键 词：桥梁工程 混凝土箱梁 热-力耦合 广义剪力滞 

分 类 号：TU111.1[建筑科学—建筑理论]