Experimental Study On Seismic Performance Of Special-shaped Column Interior Joints Reinforced By Fiber Concrete

The special-shaped reinforced concrete columns have been widely used in China in recent years. To develop and improve special-shaped columns of reinforced concrete, domestic researchers have done lots of tests on components,such as beam-column joints and RC frames of special-shaped columns. The results show that: Since the form of special-shaped column section makes the joints of special-shaped column weaker than those of rectangular columns, the building height and the scope of application of special-shaped column structure are limited. It is important to improve the seismic performance of joints of special-shaped column structure, which increasing the building height and expanding the scope of application.In this paper, the author proposes that fiber concrete can be used to reinforce the weak parts of special-shaped columns structure, and demonstrates the feasibility by theoretical analysis and low-cyclic reversed load test on joints of special-shaped column reinforced by fiber concrete and the joints of ordinary concrete special-shaped column under the same condition.In this paper, the author has applied the joint model of polypropylene fiber reinforced concrete, steel fiber reinforced concrete and ordinary fiber reinforced concrete special-shaped columns to core area of the joints of special-shaped columns and beam ends intersecting the core area, low cyclic tests are conducted, the seismic performance of the six special-shaped column's joints are carried on. The results show that: pouring the steel fiber reinforced concrete into special-shaped column joints can improve the failure characteristics, improve the cracking load of joint core area, reduce the crack width, slow the stiffness degradation, and improve the shear capacity.In this paper, the shear mechanism of special-shaped column joints and fiber concrete joints are studied based on rectangular column joints, the bearing capacity of special-shaped column joints is analyzed, cracking load of special-shaped column joints is studied, the largest plane core shear of shaped column joint, and the plane shear of joint core as the shear fracture of core area is 0.2mm.