Situ Concrete Hollow Floor. Tube Core Mode Stress Analysis And Design Method

The cast-in-situ hollow concrete floor system will be more widely used inmultiple-story and high-rise buildings for its advantages: low structural height andsmall deadweight and relatively high stiffness and convenient construction and thepredominance of noise isolation, heat insulation, thermal retardation. The mostvulnerable spot during application now is the inner mechanics analysis of thecast-in-situ hollow concrete floor system. Because of the different arrangement waysof hollow and dark beam, the phase contrast of the inner mechanics distribution isvery large. It is difficult to know the state of stress and strain distribution in the innerhollow floor from microscopic view because of the limitation of experiment research,although we can see the deformation trait from macroscopic view. The detailconstitution design of the hollow floor lacks research results to refer to, and the designtheory of hollow floor is not perfect. We analyze the hollow floor system as a spatialmodel by using finite element divided finely. From that the stress and deformation ofthe hollow floor can be reflected more actually. This paper will analyze the stressperformance of the whole hollow floor system by using the ANSYS element software,and compare the results of it with the analysis results of the PKPM design software.The thesis proposed the comparative analysis on solid and hollow slabs under theideal constraint condition by adopting the same solid isoparametric elements andmeshing methods. By comparing the compute results with classical result, it wasproved that the divide methods was accurate. That supplied the reference fordetermining the element type and meshing ways for the later finite analysis. Bycomparing the stress and deflection of the hollow floor supported by opposite sideduring the two conditions, it is proved that the stress and stiffness of the hollow floorsectional areas are different in the transverse and longitudinal directions. Thetransverse section stiffness is about 0.97 times of stiffness of the longitudinal section.According to the finite analysis methods mentioned above, cast-in-situ hollowand solid floor supported by column were computed respectively. The influence tostress and deformation brought by the holes and basic properties were analyzed. The stress and deflection distribution of the hollow floor is similar to that of the solid floor,but they are different in details. After comparing the results of ANSYS software withthe results of PKPM (SATWE) software, the amendment advice about the results ofPKPM (SATWE) software was put forward., and auxiliary value was supplied fordesigner to refer to. The ratio coefficient of the moment of flexure of the column stripand middle strip to that of all was put forward. Also, the ratio coefficient of thesupport negative moment of flexure and the midspan positive moment of flexure ofthe column strip and middle strip to that of all respectively ware put forward. Thesuggestion about the direct design method of the tube hollow floor was supplied. Thetables of distribution coefficient were listed.