Calculation of nodes of monolithic frames with reinforcement stressed on concrete in the settlement complex "LIRA-CAD"

Abstract

The stress-strain state of sloping cross-sections remains poorly understood (in comparison with normal cross-sections), which is confirmed by the absence of a single method of calculation that would take into account all factors affecting the operation of reinforced concrete elements with simultaneous bending moment, action and longitudinal force. Pre-tensioning can be carried out both with and without adhesion of a stressed reinforcement with concrete. The difference between the post-tension technology and the widely known pre-stress (carried out in the conditions of the WB plant) is that the stressed reinforcement is tensioned after concreting and concrete with sufficient transfer strength (approximately 70-80% of brand strength). To ensure that the tension of the reinforcement is possible, after the concrete has hardened, it must be able to move freely in the concrete. For this purpose, on-elastic fittings are placed in channels (made of metal or plastic pipes). Efforts on concrete are made by means of the anchor devices installed at the ends. Typically, pre-stresses use arm-tour ropes arranged in structures between the upper and lower meshes of the arm-tour according to the shape of the plot of bending moments (line of the main tensile forces). When tensioning the ropes, the tension of the compression of the concrete (from the force of tension P) and the unloading force (reactive pressure) arise, which changes its direction on the supports in non-different structures. The calculation of the support units with curvilinear tension reinforcement is very important when designing these structures. One of the important issues is the proper modeling of such nodes in computational complexes to obtain reliable results (stresses and displacements).