The Mechanical And Numerical Analysis On Crack Of Basement Bottom Concrete Slab

It is a normal phenomenon that most of high buildings appears different degrees and kinds of cracks during the construction period and usage.High buildings were wide used,while basement bottom slab cracking problems have become increasingly prominent. The crack,not only influence structural durability and reduce the mechanical performance, but also may lead to leakage.This paper mainly applys the effect of upper load and subgrade differential settlement and concrete damaged plasticity to the basement bottom slab,which has initial damage caused by crack appearing in the construction period, to observe the stress and settlement and damage field of basement bottom slab.In the thesis, the Mechanical on crack of Basement botton slab has been illustrated.Basde on the theory of unsteady temperature field, using the analysis software of ABAQUS finite element, establishing three dimensional model and solving the temperature field of basement bottom slab with Sequentially coupled thermal-stress analysis. It summarizes the distribution of temperature field of botton slab,which will be put on the basement slab as predefined fields to get the distribution the thermal stree of bottom slab. The basement bottom slab with initial damage,which caused by crack appearing in the construction period, is simulated by computer under the effect of upper load and subgrade differential settlement and the concrete damaged plasticity to get the distribution and value of damage field and strains.Finally, through the definition of equivalent plastic strains can get the developed direction of crack.The direction of the vector normal to the crack plane is parellel to the direction of the maximun principal plastic strain,therefore the direction can be viewed through the direction of maximun principal plastic strain.Through the research of this thesis get the distribution of temperature field and thermal sress field, and the settlement and damage field of slab with the the effect of upper load and subgrade differential settlemen.The results of this article provide a useful reference for the crack control of basement bottom slab.