Temperature And Shrinkage Effect Analysis And Control Methods Of Overlong Concrete Structure

With the rapid development of contemporary economic construction and the rise ofthe construction technology level, more and more overlong concrete structure inlarge-scale public buildings and industrial buildings appear. The characteristic ofoverlong concrete structure is its length far more than the rules and regulations in ourcountry about adjustable seam limits. Temperature and shrinking stress of concrete isvery complex, and is the main causes of the crack of this kind of structure. So theanalysis of temperature stress and the study of effective control technology on crack ofoverlong concrete structure has vital significance.The main research include:(1) Analysis overlong concrete structure under season temperature difference, theinternal force distribution characteristics under the temperature and Shrinkage Effectand its influential factors were analyzed; Draw the conclusion：in the structure design,more attention should be paid to the design of the structural constraint members (shearwall, column, etc), try to control the bottom column, shear wall lateral stiffness. Thereasonable high scale of the first floor have important influence to reduce the effect oftemperature shrinkage.(2) Analysis the effect of the overlong concrete structure under instantaneoustemperature difference effect. By comparing the structure effect under the uniformtemperature field, grad temperature, linear instantaneous temperature load, get thedistribution characteristic of internal force and deformation under sunshine radiationload. Linear temperature effect on the top floor beam, plate component have more greatinfluence, and has no connection with structure length factors, and the verticalcomponent have small effects. The average temperature difference on the roof, lineartemperature difference is the major effect factors of the sunshine radiation temperaturedifference. So as long as to take good thermal insulation measures to roofing, this canreduce the adverse impact by sunshine radiation temperature difference.(3) Reference the mature experience of brigde project-installing the rubber bearingin the concrete frame structure, and the effectiveness and practicability is proved by thischapter and section. The installation of rubber bearing on column of the bottomstructure, the top structure can effectively reduce the ground floor temperature stressand the top of floor stress caused by sunshine radiation temperature difference, it releasethe shear and moment of column constraints egative internal force, significantly reducethe beam-column stress, especially stress of the most outside column.(4) Combining with a project, take into account of the concrete creep and transient shrinkage properties, the construction sequence including the late casting strips, themost adverse temperature variations in the life of the building structure fromconstruction, and the rubber bearings of the limited constraint stiffness concept. Thecomputation results indicate that the approach, the construction simulation oftemperature variation, the shrinkage and effects of concrete,and the casting strip effect,can be widely applied to the analysis and calculation of super scale and mass longconcrete structure projects. And rubber bearing application is the effective practicalmethod to control the temperature and shrinkage stress.