Experimental Study On The Seismic Behavior Of Unbounded Partailly Prestressed Concrete Frame Column

Reconcrete frame structure is widely used in building field, and the collapse-resistantcapacity of frame structure mainly depends on the columns’ design. So it is a furtherresearch topic to control the residual deformation and improve the seismic behavior of thecolumn, due to that the column always appears large horizontal displacement in process ofearthquake and residual deformation after seismic.The feasibility and applicability islimited because of the little researching of reinforced concrete frame structure withunbounded prestressed steel strand.The paper produced five unbounded partially prestressed concrete frame columns,which are divided into two groups. In order to fully understand the effect of prestressdegree and pre-axial compression ratio for the reismic behavior and recovery performanceof unbounded partially prestresses concrete frame column, pseudo-static tests are conducted,covering some important factors,for example, the machanical behavior, the failure, crackingmoment, ultimate moment, hysteretic curve, skeleton curves, ductility, energy dissipationcapacity, stiffness and strength degradation as well as its re-centering capacity.The results show that the reinforced concrete frame column with unboundedprestressed steel strand is not conducive to the improvement of the energy dissipationcapacity. Enhancing the prestress degree, the column’ stiffness and ultimate bearingcapacity is degradated, while the ductility asnd re-centering capacity is improved. Theimprovement of pre-axial compression ratio, decreases the stiffness of columns,re-centering capacity and ultimate bearing capacity, but the ductility is increased. Theformula which is suitable for prestressing loss and ultimate stress of tendon of flexuralmember is also applies to unbounded partially prestressed concrete frame columns. Whilethe formula that for cracking moment and ultimate moment needs to be modified.