Study Of Design Method On THIN-WALL Core Box Cast-in-site Reinforced Concrete Hollow Floor System

Cast-in-site concrete hollow floor has been used widely in china. But its design method is not very mature. Combined with a project financially supported by the Construction Bureau of Hunan Province, some studies on this floor have been carried out in this thesis. The valuable results achieved are outlined as below:1. Compared with the current concrete criterion, a method for the stiffness of thin-wall core box cast-in-site concrete hollow floor which is analyzed in this thesis is proposed. Comparing numerical analysis results and testing results with the ones achieved by the experimentation, it is found that they are tallied well.2. A rational finite element model of thin-wall core box cast-in-site concrete hollow floor is established and such floor is made a non-linear analysis in ANSYS which is an international common software. Comparing numerical analysis results and testing results with the ones achieved by the proposed formula, it is found that they are tallied well, so the validation of the above two methods is verified.3. The ultimate bearing capacity of such floor is worked out by applying yield line theory to thin-wall core box cast-in-site concrete hollow floor. And it is proved to be feasible according to the theoretic analysis. Moreover, membrane effect is taken into account for calculating. Actually the application and the feasibility of this method are testified by contrasting to the subsistent testing.4. The elementary analysis about the geometrical parameter influences of plate thickness and breadth of rib beam on mechanical properties of the thin-wall core box cast-in-site concrete hollow floor is also made. A single geometrical parameter on mechanical properties of such floor system is set forth and the fitting scale for these parameters is determined to provide the reference when designing. The method for design thin-wall core box cast-in-site concrete hollow floor using common structural computing software is put forward and the scale for the magnifying stiffness coefficient of the spandrel beam and middle beam is discussed. Furthermore, the results are amazing in agreement with the ones by finite element analysis. So it is a good way to calculate the internal force and the deformation of such floor.