The Earthquake Engineering Online Archive

Cyclic response of RC beam-column knee joints: test and retrofit

Mazzoni, Silvia; Moehle, Jack P.; Thewalt, Christopher R.

UCB/EERC-91/14, Earthquake Engineering Research Center, University of California, Berkeley, 1991-10, 24 pages (515/M29/1991)

Two reinforced concrete beam-column knee joints were tested under cyclic loading to determine the seismic response of knee joints designed according to the provisions of American Concrete Inst. ACI 318-83 and ACI 352-85. The tests consisted of cyclic opening and closing of the connection until the load-carrying capacity was reduced to half the initial value. Following testing, one of the connections was retrofit in an attempt to restore the original strength without modifying the original dimensions. The retrofit consisted of added U-shaped bars to constrain the column hook extensions and diagonal reinforcement across the inside corner of the joint to transfer tension across the joint during opening. The retrofit test results are discussed.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-91-14.pdf (1 MB)