ABSTRACT
A statistical study was performed to evaluate the cyclic instability of steel beams with reduced beam sections (RBS). Based on test results of 55 full-scale specimens, regression analyses were performed to evaluate the relationships between response quantities and slenderness parameters for buckling. As the RBS moment connection is becoming popular after the North-ridge, California earthquake in 1994, lateral bracing of RBS beams has become a concern. Plastic rotation and strength degradation rate were selected as response parameters for the statistical study. Dekker et al. showed that, under negative bending, the lateral-torsional buckling resistance of a steel beam is dependent on the extent to which the web can transmit the restraining action to the unstable bottom flange. A statistical study on the cyclic instability of steel moment connections with RBS was performed. A database of 55 full-scale RBS moment connection specimens that were tested cyclically was used for the regression analysis.
