Structural steel design ASTM Standard The primary purpose of this book is to present the design procedures for steel buildings usinga limit states or strength design approach in a practical, concise, and easytofollow formatthat is thorough enough to include the design of major structural steel elements found in steelbuildings. In the United States, both the load and resistance factor design method (LRFD) andthe allowable strength design method (ASD) are prescribed in the latest standard for thedesign of steel buildings from the American Institute for Steel Construction, AISC 36005.Although the latest AISC manual follows a dual format, with the LRFD requirements placedside by side with the ASD requirements, only one of these two methods is usually taught indetail at most colleges. For the design of steel bridges in the United States, the mandateddesign method for bridges receiving federal funding is the LRFD method, and most civilengineering, architectural engineering, and civil engineering technology undergraduate programs in the United States offer at least one course in structural steel design using the LRFDmethod 1, 2. In addition, many countries, including Australia, Canada, France, NewZealand, and the United Kingdom (among many others) have long adopted a limit statesdesign approach similar to the LRFD method for the design of steel buildings, and most ofthe research in steel structures uses the limit states design approach. A comparative study ofthe cost differences between allowable stress design and LRFD methods for steel highrisebuilding structures indicated a cost savings of up to 6.9% in favor of the LRFD method 20.In this era of global competitiveness, we believe that the trend is toward the LRFD method,and in view of the foregoing, we have adopted the LRFD method in this text.