Non-linear macro modelling of cyclic response of non-seismically detailed reinforced-concrete connections

摘要

Past earthquakes show that a large number of existing reinforced-concrete (RC) buildings sustain relatively substantial damage especially at the beam-column connections where it is mostly caused by either diagonal shear cracks due to the absence of transverse reinforcement or by bar slippage due to the insufficient bond length of the beam bottom bars. Slip of the beam longitudinal reinforcement in the joint and shear deformation of the joint panel significantly decrease the rigidity of the joint and make a significant contribution to the lateral response of RC buildings. In the current study an efficient non-linear macro model in the OpenSees software platform was used to simulate the non-linear behaviour of joints which fail under joint shear cracking and bar slippage mode. The proposed method is validated by experimental results for both seismically and non-seismically detailed external RC beam-column connections. The non-linear macro modelling results of seismic joints were compared with those of specimens with non-seismic joints. The analytical results confirmed that the proposed joint element successfully predicted the experimental cyclic behaviour of beam-column connections, and it was also found that the rigid joint assumption was not appropriate when assessing the behaviour of existing non-seismically detailed structures.