Experimental Study On Seismic Behaviour Of Prefabricated Reinforced Concrete Column To Steel Beam Hybrid Joints

To meet the needs of the industrial development of high-rise building industry inour country, a new through-column-type reinforced concrete column-steel beam(RCSfor short) hybrid joints is proposed based on the efficient RCS hybrid structure. Thejoint core of such new hybrid joints contains a steel bucket, encased steel web plate,horizontal stiffeners and has on transverse stirrups. Embedded high strength steelbolts are adopted to connect the steel beams to the joint. Such new hybrid joints havehigh shear strength, fabrication convenience and replacement feasibility of damagedsteel beams.Twelve half scale through-column-type RCS hybrid joints were tested undercyclic loading to investigate the effect of strong joint coefficient i, details of steelweb plate and axial compression ratio to the failure modes, hysteretic performance,energy dissipation capacity and deformation composition of specimens. Followingcollusions were attained based on experimental study:(1) With decrease of the, the failure mode of specimens is converted fromflexural failure of steel beams into shear failure of joint core.(2) The hysteretic curves of specimens failed due to beam flexural failure have aplump shape with good energy dissipation capacity while the hysteretic curves ofspecimens due to joint shear failure have a pinched inversed “S” shape with poorenergy dissipation capacity.(3) Shear strength of the joint is remarkably increased while shear deformation isreduced because of the encased steel web plate which can fully provide its shearstrength. The principal tensile strain of the encased steel web plate decreased with theincrease of the web thickness.(4) The encased steel web plate can be yielded or even hardened while the jointwas subjected large shear forces. The shear strength of the joint has no significantdegradation due to the remarkable plastic deformation capacity of the steel web plate.(5) Details of connection using embedded high-strength bolts are valid and noobvious separation deformation was observed. Such details can be referenced for engineering practice.(6) Story drift of specimens is mainly caused by the flexural deformation of steelbeams and RC columns while the shear deformation of joint core is neglectable. Withthe decrease of the strong joint coefficient i, the contribution of flexural deformationof steel beams to the story drift decreased while the contribution of flexuraldeformation of RC columns increased.(7) Considering the confinement of the steel bucket to the concrete in joint core,the calculation formula of shear strength of the joint is proposed based onsuperposition principle. Calculation results agree well with test results. Thecalculation method can be referenced for the engineering design practice.