The publication suits a broad audience, including practicing engineers, professional engineering examination candidates, undergraduate and graduate students attending an LRFD class and newly graduated engineers who have been taught the Allowable Stress Design (ASD) method and want to become familiar with the LRFD method.

From the Preface
The purpose of Structural Steel Design (LRFD) is to provide an understanding and appreciation of the Load and Resistance Factor Design (LRFD) method for the design of steel structures. The design applications presented are based on the third edition of the Manual of Steel Construction, LRFD, published by the American Institute of Steel Construction, which is adopted by reference in the 2003 International Building Code, published by the International Code Council. The Manual of Steel Construction contains the specifications for steel buildings, properties of structural shapes, design data and commentary. It also provides a comprehensive interpretation and extensive coverage of the specification together detailed design examples to illustrate its application. The format of this text closely follows that of Column 1 of this series, which was based on the Allowable Stress Design (ASD) method, so as to illustrate the differences in the two techniques.

The Allowable Stress Design method is the traditional design method adopted for the design of steel structures, and the most recent edition of the specification was published in 1989. The method is based on elastic theory and requires that the stresses produced in a member by the applied loads must not exceed a specified allowable stress. In 1986 the American Institute of Steel Construction introduced the alternative design method, the Load and Resistance Factor Design (LRFD) method. In this technique, factored loads are applied to a member to determine the required ultimate strength and this is compared with the product of the member's nominal strength and an appropriate reduction factor.

The principal advantage of the Load and Resistance Factor Design method is that, by applying a statistical analysis to the random values of loads and member strengths, a uniform factor of safety may be achieved for all types of structures. Load and Resistance Factor Design models the behavior of the structure at ultimate loads and provides an accurate estimate of the strength of the structure. In addition, the load and resistance factor specifications are based on current research and developments in steel construction that have not been incorporated into the Allowable Stress Design specifications.

About the Author
Dr. Alan Williams was educated in the United Kingdom where he obtained his B.Sc. and PhD. degrees at Leeds University. He subsequently has had extensive and diverse experience in the practice and teaching of structural engineering.

Dr. Williams' practical experience includes bridge design with the Division of Roads in Zimbabwe and the design of bridges, industrial and commercial structures as a Consulting Engineer in South Africa and the United States. He is currently employed as a Senior Engineer with the State of California Department of Transportation.

His academic positions include Associate Professor at the University of Science and Technology in Ghana, Professor of Structural Analysis at Ahmadu Bello University in Nigeria, External Examiner at the University of Cape Town, and Lecturer in structural steel design and reinforced concrete design at the University of California, Irvine.

The author's published works include text books on structural engineering design, structural analysis, seismic design and reinforced concrete design. He has authored numerous technical papers for international journals and conferences.

Dr. Williams is a Fellow and Life Member of the Institution of Civil Engineers, a Chartered Engineer in the United Kingdom and a registered Structural Engineer in California.