Study on seismic behavior of concrete square columns reinforced by ultra-high strength steel bar and partially confined by angle steel
The concrete square columns reinforced by ultra-high strength steel bars with low bond-strength(referred to as RC columns)possess a drift-hardening capability up to large drift with small residual drifts,but of which the energy dissipation capacity is unsatisfactory.In order to improve the lateral strength and energy dissipation capacity of the RC columns with self-centering capability,a strengthening method was proposed to partially confine the RC columns by angle steel.Four RC columns partially confined by angle steel with one counterpart RC columns without angle steel were fabricated and tested under reversed cyclic lateral load while subjected to constant axial load.The effects of the presence or absence of angles,angle thickness and axial compression ratio and shear span ratio on the seismic behavior of RC columns were discussed.The test results show that the lateral force of all the test columns continued to increase until drift ratio of 4%.The residual drifts were within 0.5%and 1%with the drift ratio of 2%and 4%,respectively.That is,the corresponding repairable probability of the specimens were 100%and up to 50%.Compared with the non-angle steel specimen under the same axial compression ratio,the flexural strength of specimens with angle steel increased by up to 47%,the single-cycle energy consumption increased by up to 94%,and the cumulative energy consumption increased by 24%.With the shear span ratio increases,the load capacity of the test column decreases significantly.With increasing thickness of the angle steel,the increasing rate of the lateral strength of the columns increased,while the increasing rate of the energy consumption decreased.
万方数据
维普
