The Collapse of the World Trade Center Twin Towers - A Metallurgist's View

Frank W. Gayle, National Institute of Standards and Technology

The National Institute of Standards and Technology conducted a 4 year investigation of the collapse of the World Trade Center Towers at the request of Congress. The investigation addressed many aspects of the catastrophe, from occupant egress to factors affecting how long the Twin Towers stood after being hit by the airplanes, with the goal of gaining valuable information for the future. The investigation required substantial metallurgical analysis of structural steel from the Twin Towers. The analysis included characterization of mechanical properties, failure modes, and temperature excursions seen by the steel. This talk on the metallurgical investigation will describe the structure of the towers, the recovered steel, and special issues faced in the analysis of the steel. In addition, major results and conclusions of the NIST Investigation will be presented, along with recommended and enacted changes in building codes.

Dr. Frank W. Gayle is Deputy Director of the U.S. Advanced Manufacturing National Program Office (AMNPO), an interagency team with participation from all Federal agencies involved in manufacturing.  Principal participant agencies currently include the Departments of Commerce, Defense, Education and Energy, NASA, and NSF. The AMNPO reports to the Executive Office of the President and operates under the National Science and Technology Council.  The office two priority focus areas:  1) enabling industry-led, private-public partnerships focused on manufacturing innovation, including the President’s proposed National Network for Manufacturing Innovation, and 2) enabling a coordinated “whole of government” focus on advanced manufacturing initiative to facilitate collaboration and information sharing across federal agencies.

Prior to joining the AMNPO in December 2012, Dr. Gayle worked 25 years in the Metallurgy Division of the National Institute of Standards and Technology, in positions from research metallurgist to Division Chief.  As Division Chief, he was responsible for broad support of industry needs in measurements, standards, and data in the application of metals. The primary core expertise of the division is thermodynamics and kinetics applied to phase transformations in materials, electrochemistry, magnetic and electronic materials, mechanical properties, and modeling of materials phenomena.

His personal research has covered a wide range of materials, including quasicrystals, lead-free solder, and aerospace materials ranging from the Wright Flyer to the Space Shuttle. In addition, he led the team of experts addressing steel forensics aspects of the NIST World Trade Center Investigation.

Dr. Gayle holds a Doctor of Science degree in Metallurgy from the Massachusetts Institute of Technology.  He also earned a BS in Civil Engineering and a MS in Materials Science from Duke University. Prior to coming to NIST, Dr. Gayle spent 11 years in industry in the field of alloy development for aerospace applications.

Major accomplishments and awards include twice winning the Department of Commerce Gold Medal (the highest award from the Department), the Duke University Paper Airplane Contest, and being the only metallurgist in the world over six feet tall who can walk on his hands.

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