Feb. 2-24-2020
by Adolfo Pesquera
Corpus Christi (Nueces County) — The Texas Department of Transportation reaffirmed its decision to replace the engineering designer of the new Harbor Bridge main spans, emphasizing in a Thursday statement that the original designer had mischaracterized its role in a disastrous Florida bridge failure.
In January, TxDOT announced that it has requested Flatiron-Dragados LLC, the joint venture on the $800 million U.S. 181 bridge replacement project, to replace FIGG Bridge Engineers (FIGG) as designer of the main spans.
FIGG protested the order and claimed that a third-party forensic engineer firm–Wiss, Janney, Elstner Assoc. Inc.–had determined there was faulty construction in the March 2018 Florida International University pedestrian bridge collapse. FIGG claimed it had no role in the construction, only in the design.
The 175-foot-long collapsed section resulted in six deaths, eight injuries and much property damage. This led to separate investigations by National Transportation Safety Board and the Occupational Safety and Health Administration.
In a lengthy statement issued Feb. 20, TxDot Executive Director James M. Bass said the same individual who served as Engineer of Record on the Florida bridge project was in that post on the new Harbor Bridge project. He began by noting TxDOT had questions about the main cable supported spans that were not adequately addressed, and that parallel some of the issues in the NTSB report.
“TxDOT had questions on the FIGG design of the main spans that had not been adequately addressed and that parallel some of the issues identified in the NTSB report,” Bass said. “Prior to release of the NTSB report, FIGG continued to minimize its role in the tragedy and in an October 8th press release the company stressed conclusions from the engineering firm it hired that the collapse resulted from ‘a failure by contractors to conform to the final bridge design plans and comply with state of Florida construction requirements.’”
However, the NTSB found a number of actions by FIGG that contributed to the collapse:
- “…the probable cause of the Florida International University (FIU) pedestrian bridge collapse was the load and capacity calculation errors made by FIGG Bridge Engineers, Inc., (FIGG) in its design of the main span truss member…”
- “Factors in the collapse included bridge design errors, …and lack of redundancy in the bridge design.”
- “The design of the pedestrian bridge did not include redundancy in the bridge load path. As a result, when the 11/12 nodal region failed, the bridge collapsed. The design firm incorrectly believed that the bridge had a redundant design.”
Similarly, a July 2019 investigation of the Miami bridge collapse by the Occupational Safety and Health Administration (OSHA) found:
- “The bridge had structural design deficiencies that contributed to the collapse during construction stage III. The cracks on the bridge occurred due to deficient structural design.”
- “EOR should have known that the truss was a non-redundant structure and if one diagonal member failed, the entire bridge could collapse.”
“FIGG seemed to believe there was relevant information not considered by the NTSB,” Bass said. “In a responsive letter to FIGG in December 2019, the Federal Highway Administration rejected the assertions submitted by FIGG to rebut the NTSB findings and reconfirmed that there were significant errors in the final design calculations, among other issues.”
Bass said that Flatiron-Dragados has already begun the process of seeking a replacement engineering design firm for the main spans. TxDOT is allowing FIGG to continue their work with the more conventional aspects of the project.
Upon completion, the Harbor Bridge will be the longest cable-stayed bridge in the United States at 1,661 feet, and it will be the tallest structure in south Texas at 538 feet.
The change in design engineers could result in delays and affect cost, Bass added, but for safety concerns the course change is “unquestionably the right course of action. As more detail becomes available, TxDOT will share any effects this may have on the project timeline.” The project is already about two years behind schedule.
The NSTB and OSHA findings also concerned the Harris County Toll Road Authority. When TxDOT first took action, the Harris County authority order a work stop on another FIGG project–the main pylons of the cable-stayed segment of the $962 million Sam Houston Tollway Ship Channel Bridge replacement project. FIGG is being allowed to submit a redesign.
adolfo@virtualbx.com
