EXPERIMENTAL AND STUDY ON ECCENTRIC COMPRESSIVE PERFORMANCES OF REINFORCED CONCRETE COLUMNS WITH REBAR HRB635

Hot-rolled ribbed steel bars of 635 MPa are a new high-strength metal material produced by hot rolling and micro-alloying processes. Compared with heat-treated and cold-rolled high-strength steel bars, they have significant advantages of high strength, good ductility, low cost. In order to study the eccentric compressive performances of concrete columns reinforced with hot-rolled ribbed high-strength rebars of 635 MPa, a total of 20 high-strength reinforced concrete columns with hot-rolled ribbed high-strength rebars of 635 MPa were tested under the eccentric loading. The test parameters were load eccentricity ratios, longitudinal reinforcement ratios, stirrup strength and aspect ratios. The typical failure modes and mechanical properties of the columns were revealed as well. Moreover,deflection curves of columns subjected to eccentric compressive loads and development rules of cross-section strain were obtained. The results indicated that the failure modes of the columns with hot-rolled ribbed high-strength rebars of 635 MPa mainly included compressive failures subjected to large or small eccentric loads. The eccentric compressive strength of columns was enhanced with the decrease of the load eccentric ratios and the aspect ratios, and with the increase of the longitudinal reinforcement ratios and the decrease of stirrup strength. The ductility properties of the columns were obviously improved with the increase of the stirrup strength and the longitudinal reinforcement ratios. Based on the code of GB 50010-2010, the predicted eccentric strength of the columns was compared with those by the experiments. The results showed that the current code could be used to evaluate the eccentric bearing capacity of reinforced concrete columns with high-strength hot-rolled rebars of 635 MPa accurately. The study might provide scientific reference for application of the hot-rolled ribbed high-strength rebars of 635 MPa in concrete structures.