DESIGN RECOMMENDATIONS FOR TYPE 2 HIGH-STRENGTH REINFORCED CONCRETE CONNECTIONS

The present recommendations of ACI-ASCE Committee 352 for the design of ductile moment-resistant beam-column connections limit the joint-shear stress to a gamma factor relationship, where the gamma factor is a function of the type of joint and loading condition. Test results of corner connections subjected to inelastic cyclic loading show that when a frame is constructed with high-strength concrete with compressive strength between 8000 and 14,000 psi, the equation becomes unconservative. In addition, the current recommendations for joint confinement, which were devloped for normal strength concrete, cannot be satisfied for high-strength concrete frames. Based on the test results, new requirements for allowable joint-shear stress as well as joint confinement are presented to insure ductile behavior of frames.