A comparison of Seismic Behavior of Reinforced Concrete Special Moment Resisting Beam-Column Joints vs. Weak Beam Column Joints Using Seismostruct

Abstract

This paper focusses on a numerical model of a Reinforced Concrete Special Moment Resisting frame beam-column joint. The software chosen for this purpose is Seismostruct. The experimental models chosen for this purpose; referred to as Model-1 (Code Compliant), and Model-2 (Non-code complaint), are two-story twobay frames based on experimental model scaled at 1:3, and tested in University of Engineering and Technology Peshawar. Link elements that follow a distinct predefined constitutive law based on Kim (2012) and Takeda (1970) have been introduced at beam-column joint interface to simulate the failure mechanism in joint panel. Roof displacements, base shear and local damage mechanism of the numerical analysis are compared with the experimental results for the verification of the calibrated numerical models. The results showed close similarity of experimental data with numerical results with a percentage error of less than 5 percent and showed a very close resemblance of local damage mechanism. The numerical models obtained is further used to perform the seismic evaluation of code compliant and code deficient models and results like drift profile and inter-story drift ratio are calculated. Furthermore the response of both models against DBE and MCE is also determined and results shows that beam-column joints in code compliant as well as code deficient models behave in an inelastic manner and hence considering a beamcolumn joint element as a rigid panel in MCE analysis is not a valid assumption. In addition to shear cracking, bar slip mechanism was also generated in code deficient model which caused in an increased story drift, which can be prevented by adequate design of beam-column joint assemblage providing confinement for the concrete strut mechanism and proper bond anchorage to avoid bar slip mechanism.