| Coupling beams between openings are the main plastic energy dissipation elements of coupled walls, but whether short coupling beams could ensure that shear failure wouldn't take place before coupling beams have reached certain displacement ductility or not, is still a problem of engineering which hasn't been solved and is one of the critical problem of the code for design of concrete structures which remains to be solved. In this paper, based on the experiments of three short coupling beams under reversing long cyclic loading, the seismic ductility of the coupling beam which is strictly designed by the code for design and construction of reinforced concrete high-rise structures (the draft asked for advise in 2000) was found out and the influence of the increase in stirrups besides the strengthen of longitudinal detailing reinforcement on the coupling beams was studied. Then the coupling beams with new reinforcement layout were made an inquiry into, and the improvement on the seismic behavior by coupling beams diagonally reinforced with a few rows in end regions was found out At last, based on the observations of the experimental phenomena and the analysis of the measurement result, and by the comparison of seismic behavior by making use of hysteretic response, ductility and energy dissipation behavior, a conclusion is presented: the code for design and construction of reinforced concrete high-rise structures (the draft asked for advise hi 2000) can't ensure that the coupling beams have fairly good seismic ductility; the result of improvement of the seismic ductility of the coupling beams by the increase hi stirrups besides the strengthen of longitudinal detailing reinforcement wasn't obvious; the coupling beams diagonally reinforced with a few rows in end regions have fairly good mechanisms, and the ductility and the behavior of energy dissipation are better than conventionally reinforced concrete coupling beams, so it is suitable to te tised in short coupling beams. |
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