New Model for Shear Failure of RC Interior Beam-Column Connections

The primary objective of this study is to point out an irrationality in the existing models for shear failure, adopted by current design codes for reinforced concrete (RC) monolithic interior beam-column connections. To investigate this issue, 20 tests of RC interior beam-column connections exhibiting shear failure are reexamined. Test data indicated that joint shear stress is not proportional to story shear. Joint shear increased until the end of the test in most specimens, even if the joint shear deformation apparently increased and the story shear decreased. Moment in section at the beam end decreased due to a reduction in distance between stress resultants at the column face. The cause of the deterioration of story shear is shown to originate from a finite upper limit of anchorage capacity of beam longitudinal reinforcements passing through the beam-column connection. A new mathematical model is introduced for shear failure of the beam-column connection to reflect this behavior.