ASD and LRFD Under Gravityand Seismic-Dominated Loads

This study examines the structural performance of a representative private educational facility constructed with a steel framing system, assessed through both the Allowable Strength Design (ASD) and Load and Resistance Factor Design (LRFD) approaches. The structural analysis followed the requirements outlined in AISC 360-22, ASCE 7, and NEC 2015. Preliminary sizing based on conventional dimensioning guidelines was found insufficient for final design purposes, as several structural members exceeded allowable DCR thresholds across stories of the building. To ensure a valid comparison, identical member profiles were maintained in both design methods during the numerical simulations. The results showed that the ASD approach consistently resulted in lower stress demands, achieving up to an 11% reduction in primary beams compared to LRFD. Elastic and inelastic story drift demands were closely aligned between both methods, remaining well within the seismic drift limits established by the code. Additionally, modal analysis confirmed a dominant translational behavior with progressive mass participation across higher modes. Although wind loads were not considered due to the structure’s limited height, the methodology could be extended to steel buildings where wind effects become relevant. Overall, the study suggests that ASD-based design may offer economic advantages while still ensuring compliance with seismic performance criteria.