BEARING FAILURE AND STRENGTH MODEL OF, BEAM-COLUMN JOINTS BETWEEN STEEL BEAMS AND REINFORCED CONCRETE COLUMNS

Abstract

This paper presents a study on bearing failure of a rigid-framed joint between steel beams and reinforced concrete columns. To have a better understanding of the bearing failure, small-scaled concrete block tests were conducted under a localized bearing loading condition. The variables considered in the tests included the concrete strength, the type and amount of steel reinforcement, and the size of the loading area. The crack and failure patterns observed were similar to the ones typically seen in the beam-column joint tests. The test results indicated that all the variables substantially affected the bearing strength and deformation capability. Based on the test results, a strength model was proposed for the small-scaled" concrete blocks, consisting of three resisting elements such as direct shear resistance, and resistances due to confinement from surrounding concrete and steel reinforcement. Applying a stress block technique using the proposed model, a strength design equation was further derived for the joint bearing failure. Comparing with eighteen interior subassemblage test results, it was shown that the equation provided conservative and consistent strength estimates with proper accuracy.