High-rise Building Basement Shear Cracks Thermal Stress Analysis And Control

The shear wall crack in high-rise building basement in Lanzhou area is a common disease, which is caused by big size, complex boundary conditions and hostile temperature conditions during the construction. It seriously affects the shear wall structure durability, even resulting in lower the security of structures because of stiffness degradationFirstly, from two angles of temperature difference and shrinkage, this paper analyze the crack formation mechanism using finite element analysis theory of temperature field and stress field. Combined with a project in Lanzhou, the basement concrete shear wall temperature shrinkage stress is analyzed, and the distance between the expansion joints of the basement shear wall is obtained. Secondly, a 3D entity model is established by using finite element analysis software ABAQUS to solve the basement concrete shear wall temperature stress and study on the concrete shear wall temperature field distribution after pouring within 7 days. The suggestion about crack control measures were put forward from the aspects of design, structure, and construction by comparing theoretical analysis and finite element calculation results with the actual engineering situation. The main researches are as follows:1. The distribution of basement concrete wall cracks is analyzed, and the temperature field and stress field finite element theory is applied to the ABAQUS finite element simulation to analysis basement concrete wall crack formation mechanism.2. Combined with practical engineering of Lanzhou, the distance between the expansion joints of the basement shear wall is 21.58 m according to the concrete shear wall temperature-shrinkage stress theory. The basement concrete shear wall temperature field of the three-dimensional entity model is get using ABAQUS, and the application software simulation obtain the distribution of temperature field of early concrete shear wall pouring, the maximum distance between the expansion joints of the concrete shear wall should be taken 21.7m. After field monitoring, the actual situation is in good agreement with the two results.3. In the early crack control, the "code for design of concrete structure", according to table 8.1.1, The soil or indoor basement wall construction joints maximum spacing of 30 m. Take into account the environmental characteristics of Lanzhou, It suggest that soil or indoor basement wall expansion joint spacing less than 21.58 m.4. Some technical measures aimed at early cracks control are proposed from the aspects of design, structure, and construction.