Parametric Exploration of Block Shear Formulations

Block shear is a mode of failure in which a steel member fails in tension along one plane and shear on a perpendicular plane along the fasteners. The design process for block shear has been at the center of debate since it first appeared in the 1978 AISC Specification and has evolved over the years. This thesis investigated the block shear design equations as they have progressively changed from the 1978 provisions for Allowable Stress Design (ASD) to the 2005 provisions for Load and Resistance Factor Design (LRFD). Block shear strength capacities were calculated for multiple designs involving coped beams, angles, and structural tees. These analytical values were compared to physical test findings available in the literature. The results of this study compare the different strength predictions to one another, as well as benchmark the AISC provisions to actual physical testing strengths. The comparisons were also used to determine whether the ASD and LRFD specifications follow similar trends. Good agreement between the predicted capacities and the results from physical testing was observed for a majority of the geometries investigated. However, capacity predictions based on increasing the number of rows of bolts for a coped beam and changing the length of the outstanding leg for an angle or tee connection were found to disagree with the test results. A finite element study was also completed to further explore the influence of changing the length of the outstanding leg of tee connections because these geometries showed considerable disagreement between the calculated capacities and the test data