Study On Equivalent Compositive Temperature Variation Effects Of Super-long And High-rise Concrete Structure

With the development of economic and building technique, the super-long and high-rise concrete structures are built more and more in our county. These buildings usually have no or less expansion joint, which leads to the length of whole structure oversteps the restrictive value of code for design of concrete structures (GB50010-2002). For the high-rise and super-long concrete structure, the comprehensive temperature difference of concrete, which is the sum of Equivalent Temperature Difference of concrete desiccation and shrinkage and seasonal Temperature Difference, is both the important factor that have to be considered in design and the main reason causing concrete cracking. So it is important to research the temperature variation and shrinkage effect of high-rise and super-long concrete structures.In the thesis, firstly, the current situation of temperature variation and shrinkage effect at home and abroad on concrete structures was introduced, secondly, the basic theory of shrinkage and creep was detailedly discoursed. thirdly, the elastic mechanics theory of temperature stress was introduced at first, at last, give a presentation of the finite element theory of temperature stress and how to analyze high-rise and super-long structure with ANSYS using 3D beam and shell element. The triformed Temperature Difference effects which are annual temperature difference, comprehensive temperature difference under considering construction progress and the comprehensive temperature under considering the late poured band and construction progress are emphasized in this paper.The main study of this thesis includes three parts. Firstly, the high-rise and super-long structure reaction under annual temperature load was analyzed, arrive at the variation tendency of internal force on beam and column and stress on floor slab. Secondly, considering the impact on shrink desynchrony under different construction period, There are two question, on the one hand, desiccation and shrinkage is out-of-step, on the other hand, seasonal Temperature Difference also caused desynchrony. Then analyze and compare the structure internal force under annual temperature load and comprehensive temperature load, obtain the reduction factor of internal force. Thirdly, the late poured band could release the early concrete shrinkage stress, using ANSYS to simulate the late poured band and construction progress, find the structure internal force after the late poured band being closured, this sloved internal force is under considering concrete desiccation and shrinkage, seasonal temperature difference of different construction progress and set-up and closure of the late poured band. At last, determine internal variation tendency grap of some structural member, then compare the result under annual temperature load, obtain the reduction factor of internal force.