Abstract:

The seismic hehaviors of steel reinforced concrete joints with plastic hinge shifting away from the heam end were investigated hased on the experimental results of 2 full-scale joint specimens under cyclic loading. In the investigation , the joints designed as strong connections were treated with dog-hone style weakening on the upper and helow flanges of the H-type steel at the heam end near the joint core , and the longitudinal reinforcement ratio ,which distrihutes from the root of heam end to the maximum weakened flange of the H -type steel , was properly in-creased.Experimental results show that the ductility factors of the 2 joint specimens are all more than 5. 27 , which meets the requirements of the ductile frame in seismic design , and that the equivalent viscous damping coefficients on the maximum load are all more than O. 30 , which reveals quite high energy dissipation of the joints. Moreover , it is indicated from analyses that the constitution of plastic hinges for steel reinforced concrete joints can not only de-crease the shear in the joint core and the stress of seam in the beam-column connection hut also improve the rotation and shear capacities of plastic hinges in the heams , thus increasing the ductility and energy dissipation of the joints.

Key words: steel reinforced concrete, composite joint, dog-hone style weakening, seismic hehavior, plastic hinge