Analytical study on seismic performance of partially prestressed concrete beam-column joints

Abstract

In this study, six partially prestressed concrete exterior Beam-Column Joints with variable prestressing force and four partially prestressed concrete interior beam-column joints with variable column axial load ratio have been analytically analyzed and assessed to evaluate their hysteretic performance under reversed cyclic loading. A Two-Dimensional finite element software program, VecTor2, is used to validate the non-linear response of beam-column joint experiments executed in Chiba and Kyoto university, Japan. The analytical result adequately simulated the interior joints in all cycles of loading while in the exterior joint a reasonable underestimation of results was obtained at the last cycle. In the partially prestressed concrete exterior beam-column joints, variation of prestressing force had little effect on the ultimate storey shear capacity. Stiffness and ductility increased significantly with prestressing force before wide shear crack formation and high prestress loss at the joint. Strength degradation after peak response was severe with increasing prestress level. This phenomenon undermined the inelastic energy dissipation capacity of the highly prestressed joints at the later cycles. The increment of column axial load in the partially prestressed concrete interior beam-column joint resulted in wider pinching while the converse created severe pinching. Premature crushing of concrete
at the joint due to high compressive stress from the column axial load and prestressing force was not observed in any of the specimens.