Temperature Crack Mechanism And Controlling Technique Of Reinforced Concrete Shear Wall Structure

In these years, with the increase of the number of high-rise buildings in cities, temperature cracks of members draw more and more public attentions. Because of the complex shapes and structures of high-rise building, there are considerable difficulties in calculating temperature stress of the reinforced concrete high-rise building. In china, temperature variations are usually not taken into consideration in design of high-rise buildings. Researches of this paper are just carried out under such a background, and as a sub-topic of "cracking mechanism and a whole set of control technique of modern concrete structure "(NO:50278031) supported by national natural science foundation, shear wall of high-rise building is chosen as an object of study. This paper studies temperature effect on shear wall structure by ANSYS software and all-round and systematical research is carried on temperature crack mechanism and controlling technique .The main work done in this paper is as follows:(l)Based on the characteristics of temperature distribution on high-rise building, how to define the temperature cases is discussed given;(2)With calculating and analyzing the temperature effects of three temperature cases for shear wall structure, distribution regularity of temperature deformation and temperature stress in the structure in shear wall and the slabs are obtained;(3)With studying the mechanism and the regularity of temperature cracks of three temperature cases in frame-shear wall structure, the distribution regularity of temperature stress(internal force) of the structure beam column and slab is obtained;(4)The susceptibility of kinds of possible influencing factors is analyzed and the methods to control crack of shear wall structure are summed up.On the basis of the research work mentioned above, some crucial conclusions are acquired as follows:(l)Temperature effects are mainly on bottom and top of the structure where temperature stress in shear wall and slab is considerable;(2)Temperature effects are mainly on peripheral member of the structure, and the internal forces in beam and column resulted from temperature variation must be taken into account;(3)Where structure arrangement changes sharply ,such as near the tip door hole window hole or joints of floors and shear walls ,and joints of floors and slabs , temperature stress is increased sharply;(4)Some effective measures to reduce temperature stress in reinforced concrete shear wall are proposed ,such as arranging properly the form of structure useless high concrete and reducing the thickness of shear wall and the stiffness of column. Controlling crack should provided setting external wall thermal system control restriction deformation and properly arrange steel for construction requirement.