The 59-story Citicorp Tower in New York, now renamed 601 Lexington Tower, was completed in 1977. The tower has a unique steel structure with perimeter mega-braced frames and a V-braced core. The perimeter mega-braced frame is supported on four 9-story tall mega columns at the base. The mega-columns are located at the center of each side of the structure instead of at the corners, which is the case for most skyscrapers.  The reason for mega-columns not being placed at the corners was the presence of a church on the NW corner of the site. Six 8-story tall V-shaped mega-braces provide lateral wind force resistance. Less than a year after the tower's completion, it was discovered that the mega brace splices did not have the code-required safety factor, and the structure was in danger of collapse during a hurricane. An emergency retrofit plan was developed and implemented to strengthen the mega-brace weak splices in two months before any hurricane hit the tower. The first part of this webinar will discuss the unique structural system of the tower, why the mega-brace joints ended up being weak, and what was done to strengthen them. The second part will focus on the engineering ethical issues of wind retrofit. For years, this case was considered an excellent example of ethical conduct by all involved, especially by the late William LeMessurier, the lead structural engineer of the tower.  However, in recent years, an article by a faculty of architecture has argued the opposite, accusing LeMessurier of violating several canons of the Code of Ethics for Engineers.  Dr. Astaneh will examine the accusations of unethical conduct by William LeMessurier and, based on the facts involved, show that such accusations are not valid. The conduct of William LeMessurier and others involved in the emergency wind retrofit of the CITICORP Tower remains an excellent example of ethical conduct in structural engineering to save lives. References and Recommended Further Readings:

1. Code of Ethics of National Society of Professional Engineers (NSPE) (PDF)
2. NSPE Ethics Reference Guide (PDF)
3. Ethics, Technology, and Engineering, a 2011 book by Ibo van de Poel and Lambèr Royakkers, Wily-Blackwell. (Amazon page)
4. Concepts and Cases-Engineering Ethics, a 2019 book by Charles E. Harris et al., published by Cengage. (Amazon page)
5. The Ethical Executive, a 2010 book by Robert Hoyk and Paul Hersey, Stanford Business Books. (Amazon page)
6. Joe Morgenstern (1995), "The Fifty-Nine- story Crisis", The New Yorker, May 29, 1995. Pages 45–53.
7. Eugene Kremer (2002). "(Re)Examining the Citicorp Case: Ethical Paragon or Chimera", Cross Currents, Fall 2002, Vol. 52, No 3. Brady, S. (2014, February).
8. Citicorp Center Tower: failure averted. The Structural Engineer, pp. 14–15.
9. LeMessurier, William J. “The 59 Story Crisis: A Lesson In Professional Behavior” (video November 17,1995).

Date:  Wednesday.  February 28. 2024.  Starts: 2 – 4 pm ET Credits: 2 PDH Units

Learning Objectives:

At the successful conclusion of this webinar, you will learn the following knowledge and skills:

• The structure of the Citicorp Tower.
• The root cause of the problem of mega-brace splices being weak.
• The solution to strengthen the mega-brace splices and how it was implemented.
• The ethical issues related to the problem of the mega-brace splices.
• Why the conduct of the late William LeMessurier, the lead structural engineer of the CITICORP Tower, is an example of excellent ethical conduct of an engineer saving thousands of lives before a catastrophe occurs.

Special Webinar Instructions

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Biography

Dr. Abolhassan Astaneh-Asl is a professor emeritus of civil and environmental engineering (structures) at the University of California, Berkeley, and a 2013 Minner Faculty Fellow in Engineering Ethics and Social/Professional Responsibility in the College of Engineering. He won the 1998 T.R. Higgins Lectureship Award of the American Institute of Steel Construction, the most prestigious award in his field. He is a licensed civil engineering Professional Engineer (P.E.) in California. Dr. Astaneh is currently a structural engineering and bridge engineering consultant. He has been an expert witness in several court cases on structural and bridge engineering and construction failures. He continues his research and publications and gives lectures and webinars in structural engineering, earthquake engineering, bridge engineering, and engineering ethics.  He has published over 300 journal papers, conference proceedings, technical reports, ​and ​book chapters. He has had hundreds of press interviews on technical aspects of subjects in his expertise. He has been involved in design and construction and ​has ​done extensive research and studies of buildings and bridges for 55 years, including buildings of up to 73 stories​. He was responsible ​for ​the ​turnkey design and construction of a 17-story reinforced concrete structure in ​a ​highly seismic area. He has also done extensive bridge engineering work, including long-span bridges such as the Golden Gate Bridge and the Bay Bridge. Dr. Astaneh has performed the failure analysis of several collapsed structures, including the World Trade Center Towers and the Florida Pedestrian Bridge, a post-tensioned concrete structure.

Group Discounts Available