Study On Mechanical Performance Of The Long Span Concrete Slab With Low Ribs

With the improvement of China's economic level, now people's requirement on household is higher than ever before. The population structure of the family is dynamic, and people's requirement on space function of the house is various and changing as well, consequently the adaptable house arises at the historic moment. The keys of realizing this kind of houses that possess large space are mechanical performance and the long span concrete slab with excellent economic index. The dissertation has done a study on the mechanical performance of the long span concrete slab with low ribs by means of the ANSYS software. First of all, two substantive finite element models have been set up under the condition, which is in the same load and restriction, in order to know mechanical performance and action of the shell better. The models are different that one has the shell, which is 40mm high, and the other has not. Comparing the data from the two different slab models,the author analyzed not only the action of shell and its stresses state but also torsion rule of ribs and the deflection of the long span slab. Secondly, through analysis of a large number of data,the phenomena that the shell in the middle of area is pressed on the whole section is found, which is mainly caused by membrane effect of the shell. Horizontal distortion in the shell is restricted because of relative rigidity of the ribs. For guaranteeing boundary conditions, ribs will inevitably give the shell a reactive force against shell. Finally, Torsion rule of ribs is been found through anglicizing the relative data of displacement, which is caused by torsion of tip and bottom of ribs. Torsion is greater in three ribs on the edge and in the same rib it is greater in the area near the midspan. Generally speaking, the shell has good mechanical performance and can link the long span concrete slab as a whole, therefore the rigidity of this kind of slab is increased, and at the same time the deflection of the slab meets the normal requirement. Research on the slab is primarily preparing for following study and project and possesses certain practicability. At present, research on the calculation of this slab by means of substantive finite element is still seldom. The author hope the work in this dissertation can play a role in casting a brick to attract jade and offer reference for research on the long span space structure of household and practical application.