Cyclic Behavior of Exterior Reinforced Beam-Column Joint with Cross-Inclined Column Bars

Abstract

The poor design practice of beam column joints is compounded by the high demand imposed by the adjoining flexural members (beams and columns) in the event of mobilizing their inelastic capacities to dissipate seismic energy. Unsafe design and detailing within the joint region jeopardizes the entire structure, even if other structural members conform to the design requirements. Beam moment reversals can produce high shear forces and bond breakdown into the joint resulting in cracking of the joint. The most important factors affecting the shear capacity of exterior RC beam-column joints are: the concrete compressive strength, the joint aspect ratio of the joints and number of lateral ties inside the joint. Advanced Reinforcement Pattern (ARP crossed inclined bars) is a feasible solution for increasing the shear capacity of the cyclically loaded exterior beam-column joints. The presence of inclined bars introduces an additional mechanism for shear transfer. External beam- column joints with crossed inclined reinforcement (ARP) modeled in Ansys Workbench showed high strength, and no appreciable deterioration even after reaching the maximum capacity. The load resisting capacity is increased as compared to that of seismic joint (IS: 13920-1993). A parametric study with cross inclined bars at the joint will be studied with different parameters like grade of concrete, tie ratio, joint aspect ratio, energy dissipation, yield ratio etc. A number of models in ANSYS 13.0 workbench and mechanical APDL are developed for different cyclic loads and boundary conditions. The joint with M50 grade of concrete is discussed in this paper.