PECULIARITIES OF CALCULATION OF U-SHAPED REINFORCED CONCRETE FRAMES WITH REDISTRIBUITON OF MOMENTS

Abstract

Reinforced concrete frames are used for the construction of both single-storey and multi-storey industrial and civil buildings and structures, as well as in hydraulic and transport construction. The frame systems are widely used in the engineering due to their high reliability while having vertical and horizontal loads of different nature. The use of the reinforced concrete frame systems is especially important now in the construction of new civil and industrial buildings with underground floors, which provide for the installation of built-in dual-use premises with protective characteristics of storage facilities. Therefore, the method of calculating the frames needs to be further improved.

The modern practice of designing of reinforced concrete frames contains a contradiction, in which the static calculation is based on the use of structural mechanics for homogeneous elastic systems, but the bearing capacity of cross-sections of frame elements is performed by deformation technique based on elastic-plastic properties of the materials. Based on this, the article improves the method of calculation of U-shaped reinforced concrete frames with the redistribution of moments due to elastic-plastic deformation of materials.

As a result of the researches it was discovered which types of frames are recommended to be calculated with redistribution of moments, the method of calculation of moments in frame elements is developed, influence of a parity of rigidity of a column and a crossbar on moment redistribution is established. It is proved that the calculation of U-shaped reinforced concrete frames with the redistribution of forces makes it possible to reduce the cost of reinforcement to 12% and simplify the reinforcement of frame elements.