THE STRENGTH OF HIGH-RISE BUILDINGS FROM MONOLITHIC REINFORCED CONCRETE TAKING INTO ACCOUNT DIFFERENT RESISTANCE AND DAMAGE OF MATERIAL

The derivation of a finite element model to determine the stress-strain state of a multi-storey building made of monolithic reinforced concrete is considered. This takes into account the dependence of the mechanical characteristics of concrete on the type of stress state, the development of plastic deformation in the reinforcement, cracking. The equations of state for the nonlinear isotropic materials proposed in the framework of the theory of A.A. Treschev, based on the parameters of the normalized stress spaces, accepted as defining relations. The characteristics of the material are determined from experiments on uniaxial tension and compression under simple loading conditions. Especially for the solution of this problem, a modification of the triangular hybrid finite element was developed for a plate of medium thickness of an arbitrary shape with five degrees of freedom in the node. The necessary equations of the finite element method for solving the problem of calculating the stress-strain state of the building taking into account the cracking, the different resistance of concrete and plastic deformations in the reinforcement obtained. The description of the methods of modeling the fictitious layers of the element corresponding to different variants of the stress-strain state of reinforced concrete: concrete layers without cracks, concrete layers with cracks, concrete layers without cracks and reinforced concrete layers with cracks in one and two directions. The results of solving the problem in form of graphs of the distribution of individual displacements in the slabs of the building. Confirmed, that taking into account the complicated properties of the material are necessary to obtain correct estimates of the stress-strain state of reinforced concrete structures under conditions of progressive cracking.

finite element method reinforced concrete, monolithic reinforced concrete, multi-storey building, multimodulus behavior, cracking, hybrid finite element

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