A Study of Bond Deterioration in Reinforced Concrete Beam-Column Joints

Sonchao Zhu and James O. Jirsa


The bond behavior and crack pattern in the joint area of reinforced concrete at different load stages are studied in order to understand the nature of deterioration of bond strength.

It is difficult to relate bond deterioration to lateral drift of frame structures under earthquake loadings. Most design recommendations and codes require the calculated inelastic interstory drift be less than 0.01 to 0.02 of the floor height. In this paper of relative inerstory drift of 0.03 is suggested for evaluating the performance of beam-column joint test specimens. Using this criterion, tests conducted at the Univeristy of Michigan, The University of Texas at Austin, the University of California-Berkeley, and the University of Canterbury, New Zealand are reevaluated.

From the reevaluation of the previous test results, design recommendations for the ratio of column width to beam bar diameter are made. Similar suggestions are made for the ratio of beam depth to column bar diameter.

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