Study On Temperature Field And Cracks For Concrete Small Cavity Block Building

In the course of popularizing and application of the concrete small cavity block building (CSCBB), the issue of temperature cracks on top floor's walls has become urgent to solve. So analyzing, calculating or simulating the cracks is essential and has theory and actual meaning. On the basis of the task of CSCBB's controlling technique, this paper deals with simulation and analyzing on CSCBB's temperature field and temperature cracks.Field test on experimental building was described at first. The distribution law of roof and walls's temperature field was summarized including their day changing and year changing. The cracks location and form on them were also introduced in detail.Confirming building's temperature field is the premise to solve crack issue. In this paper, some factors influencing its temperature field have been synthetically analyzed including the ambient temperature, solar radiation, air convection and sky radiation, ground radiation and so on. The hourly temperature of the roof and walls of the tested building in summer and winter was calculated with the finite element software-ANSYS. The results from calculation had well consistent with the experimental results.Block wall is supposed as a uniform material and having same properties in every direction, and its relation of stress-strain adopts the model of Zhejiang University Structure Lab. Aided by ANSYS, eight types of walls under level load have been nonlinear analyzed and achieved the cracking, extreme load, cracks location and form respectively. The simulation results show great agreement with experiment results. And it can be concluded that simulating cracks on CBCBB by finite element method (FEM) is feasible and reasonable.Finally, simplified experimental model was built and analyzed by ANSYS under day changing and year changing temperature field. The typical cracks on top floor's walls were achieved, so the simulation method is reliable. And it can be concluded that cracks on top floor's walls are caused by the temperature difference between floor or wall's inner and outer surface and the temperature difference between floor and walls. If the floor and wall's thermal resistance is appropriate, the cracks issue on CSCBB can be solved.In this paper, temperature field and temperature cracks on CSCBB was probed and practiced aided by nonlinear FEM. It hopes that the work can be helpful to CSCBB's popularizing and application.