February 7, 2023 - 5:00pm to 7:00pm

Initial Investigation into the Partial Collapse of the Champlain Towers South (CTS) Building in Surfside Florida

On June 24, 2021, the Champlain Towers South building in Surfside Florida collapsed without warning. The initial collapse occurred outside of the building tower, in the pool deck region. Seven minutes later, the central portion of the building collapsed; the eastern portion of the building collapsed quickly after that. The western section of the building remained standing. Professor Lehman worked with an investigative journalist team at the Miami Herald led by Sarah Blaskey to investigate the partial collapse using tools and technologies she had developed through her research on seismic evaluation of existing buildings and design of new concrete connections. The primary objective of the investigation is to understand how initial damage in a pool deck could lead to partial collapse of this flat-plate cast-in-place reinforced concrete structure with an eye towards improving evaluation methods for these structures.

This talk will address the building collapse using:

  • The timeline of the collapse as reported by witnesses.
  • Building damage photographs and videos.
  • Building plans and repair drawings and permits
  • Advanced nonlinear finite element analyses of the Level 1 slab to investigate possible initiation points and progression of damage.


Learning Objectives

  • Fundamental approach to forensic engineering of damaged and collapsed structures
  • Uses and limits of photographs and video to identify final failure modes and explore possible damage/collapse scenarios.
  • Use of high-resolution nonlinear analysis with fundamental understanding of structural behavior to investigate initiation of failure and progression of collapse.


1 CE credit will be issued for this event. CE certificates will be emailed to all attendees within a week after the event.


Cliff Dwellers Club

200 S. Michigan Ave, 22nd Floor

Chicago, IL 60604


  • Bibb Lettuce and Belgian Endive, Asparagus and Orange and Grapefruit Sections
  • Grilled Chicken Piccata Wild Mushroom Demi Glaze
  • Tiramisu


Presentation time: 6:00 – 7:00 pm

Cocktail hour: 5 – 6 pm


In Person:

Member - $60

Non-Member - $90

Live Streaming:

Member - $30

Non-Member - $45

Registration will close Thursday, February 2nd at 4pm. Contact staff@seaoi.org to inquire about registration after this date, though note that registration is not guaranteed.

About the Speaker

Dawn Lehman

University of Washington

Dawn Lehman is a Professor of Civil and Environmental Engineering at the University of Washington. She received her BS from Tufts University in 1989 and her PhD from U.C. Berkeley in 1998. She worked as a structural engineer in Boston MA between these degrees. She has been a faculty member at the University of Washington since 1999. Her research expertise lies in seismic engineering of structural systems. She has conducted research on a range of systems including reinforced concrete walls and frames, steel braced frames, as well as concrete-filled-tube, precast and reinforced-concrete bridge systems. Her research results have been implemented in codes, design manuals and provisional structural engineering recommendations, including AASHTO, AISC, WSDOT BDM, Caltrans SDM, and ASCE 41. She has authored over 100 peer-reviewed research articles. She led the technical investigation of the partial collapse of Champlain Towers South as a consultant to the Miami Herald. The team was awarded the Pulitzer Prize for Breaking News for this work.



Dennis Penepacker
Brian Lammert ( Raths, Raths & Johnson, Inc. )
John Miller ( Nayyar & Nayyar, International, Inc. )
José Medero ( ESD (Environmental Systems Design, Inc) )
Michelle Ryland ( Klein & Hoffman )
Scott Nacheman ( J.S. Held, LLC )
Dave Eckmann ( Magnusson Klemencic Associates )
Fernando Saz ( The Structural Group )
Harry Kuchma ( The Structural Group, Ltd. )
Mark Danielak ( The Structural Group, Ltd )
Roman Szczesniak ( RSJR Engineering Ltd. )
Debra Hoegemeyer ( Uptown Structural Engineering LLC )
Crystal Ramos ( ECS Midwest, LLC )
John Wysockey ( Thatcher Foundations )
Michael Bronson ( Thatcher Foundations )
samhar hoz ( ICC (International Code Council) )
Wilson Smith ( ECS Midwest LLC )
Jared D'Amico ( K2N Crest )
Sam Mittal ( STV Inc. )
Richard Drew ( Retired, UIUC )
Benjamin Sexton ( Thornton Tomasetti )
Aphrodite Angelakos ( a1a Design Group Corporation )
Tracy Naso ( Wiss, Janney, Elstner Associates, Inc. )
John McLean ( Simpson, Gumpertz & Heger )
Eduardo Prieto ( Exp Federal )
Stacey Ceretti ( Envista Forensics )
Jeff Ruhde ( Burns & McDonnell )
Nate Morriss ( Lakeshore Engineering, LLC )
Brian Boysen ( Burns & McDonnell )
Matt Wagner ( Walter P Moore )
Steve Rienks ( American Surveying & Engineering )
Alex Brown ( Vulcraft )
Matthew Hopper ( Cary Kopczynski & Company )
Barry Kravitz ( HDR, Inc. )
Adam Theiss ( Magnusson Klemencic Associates )
Cathleen Jacinto ( FORSE Consulting, LLC )
Josh Brickman
Don Jabczynski ( S.E. Enhancements, LLC )
Tom Harrison ( Muller2 )
Donald Redar ( Bulley & Andrews Concrete Restoration LLC )
Bryan Rodriguez ( Bulley & Andrews Concrete Restoration LLC )
Don Cox ( Bulley & Andrews Concrete Restoration, LLC )
Joshua Freedland ( Bulley & Andrews )
Josh Wolf ( Bulley & Andrews Concrete Restoration, LLC )
Todd Lawford ( Bulley & Andrews Concrete Restoration LLC )
Dan Stanek ( Bulley & Andrews Concrete Restoration LLC )
Robert Lau ( Klein and Hoffman, Inc. )
William Bast ( LPI, Inc. )
David Weihing ( ESD )
Stephanie Hautzinger ( CannonDesign )
Bryan Wickert ( Wallace Design Collective )
Derek Boeldt ( Jacobs )
Keli Dudek ( KeliAnn Engineering, LLC )
Jennifer Traut-Todaro ( American Institute of Steel Construction )
Bob Davies
Will Kolbuk ( Sargent & Lundy )
Brian Boysen ( Burns & McDonnell )
Jon Sfura ( Wiss, Janney, Elstner Associates, Inc. )
Nezar Abraham ( Thornton Tomasetti )
Larry Stevig ( State Farm )
Kevin Conroy ( Simpson Gumpertz & Heger )
Terrence McDonald ( Klein and Hoffman, Inc. )
Steven Jastrzebski ( Sargent & Lundy )
Jace Jackson
Stephanie Crain ( Structural Engineers Asso )
Dawn Lehman ( Speaker )
Jan Blok ( The Structural Group, Ltd. )