Analysis Of Temperature Effect Of New Super-long Basement Connected With Built Basement

In recent years,with the vigorous development of various large-scale public and civil buildings in China,more and more underground space has been developed,and a number of super-long and super-large reinforced concrete basements have appeared.Because of the need of using function,or proceeding from advantageous to the overall work of the structure,or in order to solve the waterproof problem of the structure,there are usually no or few expansion joints in the building structures.In this way,it is necessary to conduct in-depth research on the law of internal force changes caused by temperature changes in buildings and the measures to reduce the temperature effect of structures.Research and development of temperature effect is of great significance to crack control of seepage prevention in Super-long Basement Structure,and it is also the focus of attention of engineers and designers.Because the temperature effect is the main cause of cracks in structures,it is difficult to completely avoid cracks in practical projects.The Super-long Basement in this project,whose East facade is shared with the super-long basement exterior wall of the super-high-rise building which has been buried deeper,is connected with it by planting steel bars to form a super-long + super-long basement.In addition to temperature stress,there are also internal forces of members under various loads,and additional stresses caused by possible settlement differences.In this paper,the actual engineering of this Super-long Basement Concrete structure is taken as the research object,and the effect of temperature variation of the newly built Super-long Basement on the basis of rigid connection with the existing basement is analyzed.The main conclusions of the study include the following aspects:(1)The finite element model of Super-long Basement Structure in construction stage is established by using ANSYS software.The temperature effect of the basement structure under overall cooling is analyzed,and the deformation characteristics and internal force distribution of the super-long basement are obtained.The results show that the maximum deformation of the structure occurs at the end of the side wall farthest from the exterior wall of the built basement with rigid connections.With the decrease of the distance from the exterior wall of the built basement,the deformation of the structure decreases gradually,and the deformation of the exterior wall of the built basement is almost unchanged.The first principal stress of the structure appears at the bottom of the top of the basement exterior wall with rigid connections.With the increasing distance from the basement exterior wall,the first principal stress decreases gradually.The first principal stress in the vertical area of the side wall farthest from the basement exterior wall is generally lower.(2)Based on the stress nephogram drawn by ANSYS software,the distribution map of crack range of basement structure is drawn by using Vplot function command stream program in MATLAB according to whether the first principal stress of structure exceeds the ultimate tensile strength of concrete.The analysis results show that the cracks in the exterior wall of the basement with rigid connections are the most obvious and concentrated.The other side walls and the basement floor all show concentrated cracks in a certain area,but the distribution areas are different.It has practical guiding significance for crack control in practical engineering.(3)Based on the results of finite element analysis of temperature effect and crack distribution range of Super-long Basement Concrete structure,combined with existing crack control technologies and crack control principles,the crack control measures for this project are elaborated from three aspects of design,construction and material.