Crossbars of frame buildings when changing the sign of forces

A large number of reinforced concrete frame buildings are located in seismically dangerous regions. In case seismic impacts plastic strains and local destructions occur elements such buildings, which influence sufficiently on their bearing capacity stress-strain state when changing the sign internal forces. This fact is not taken into account current Russian norms earthquake-resistant construction. The numerical research beams behavior under action alternating load with regard to elastic-plastic properties reinforcement has been conducted. evaluation strain maximum value tensed relative beam force limit coefficient plasticity corresponding destruction compressed zone made. comparison results simulation experimental tests same parameters made, demonstrated good convergence calculations data both terms deformations for coefficients less than 2.5. During experiment it found that forces through cracks form bending throughout entire section height, close afterwards if does exceed For greater values closing doesn’t take place until specimens due rupture bars. According study was concluded, decrease by 40% compared reference samples as increase first semi cycle loading takes place. Also three times plasticity, concrete, observed. models 10 50 cycles have conducted asymmetry equal -1. conclusion made exceeding 1.62 insignificant beams, 10%,