超长混凝土结构在使用阶段温度应力下的裂缝控制

Crack control of super-long concrete structures under temperature stress in use stage

温度变化对超长混凝土结构的变形和内力存在较大的影响。结合鲁南高铁临沂北站站前广场项目,介绍了超长混凝土结构使用阶段温度应力的等效温差计算方法。利用有限元软件分析了降温温差作用下的结构内力,探讨了温度变化对超长混凝土结构的影响。根据计算结果及其结构特点,特选用缓粘结预应力技术控制温度裂缝,同时介绍了本项目其他抵抗温度应力的措施。结果表明:在使用阶段,随着结构降温温差的增大,超长结构最大温度应力呈线性增长。控制后浇带闭合时间和施加预应力是有效控制温度应力的方法。

Temperature changes have a great influence on the deformation and internal forces of super-long concrete structures.Based on the Linyi North Station square project of Lunan high-speed railway,a calculation method about equivalent temperature variation of the temperture stress in the use stage of super-long concrete structure was introduced.The finite element software was used to analyze the internal force of the structure under the action of temperature drop and to discuss the influence of temperature change on the super-long concrete structure.According to the calculation results and its structural characteristics,the retard-bonded prestress technology was used to control the temperture cracks.In addition,other measures to resist the temperature stress of the project were introduced.The results show that during the use stage,as the temperature drop of the structure increases,the maximum temperature stress of the super-long structure increases linearly.Controlling the closing time of post-cast strip and applying prestress are effective methods to control temperature stress.