Construction
27 Feb 13
Review finds flaws in SR520 design process
An internal review has been completed into the causes of the problems with the pontoons of the SR520 bridge, which is under construction in the US state of Washington.
“The results of our internal review show that we did not follow standards of good practice to validate the pontoon design elements, and as an engineer, that is particularly frustrating,” said Washington transportation secretary Paula Hammond. “We also did not strictly follow some of our protocols for oversight and administration of the contract on the construction site.”
Hammond requested the internal review to determine if employees or managers acted or failed to act in ways that led to greater-than-anticipated pontoon spalling and cracking, deficiencies in contract administration, and lack of proactive resolution of problems. The review also identified areas where Washington State Department of Transportation (WSDOT) can improve management, communications, and internal alignment of capital project delivery practices.
“I agree with the internal review findings that there were technical design, construction management, and decision-making failures by our employees and managers,” said Hammond. “I am directing WSDOT’s chief of staff to prepare the appropriate disciplinary actions, and make the necessary changes to agency protocols and practices.”
Hammond has said that the repairs and design modifications now being made to the SR 520 pontoons will ensure a 75-year life of the floating bridge. “We are implementing the expert review panel’s findings to make repairs to the pontoons on Lake Washington and design modifications to the pontoons still to be built in Aberdeen,” she said. “The panel agrees the pontoons are structurally sufficient, and we take our responsibility for public safety seriously. These changes will ensure the SR 520 bridge is built to the highest standards.”
During the course of bridge construction, 44 pontoons built in Tacoma will be joined with 33 pontoons built in Aberdeen for a total of 77 pontoons needed to construct the world’s longest floating bridge. Construction on the US$367 million SR 520 pontoon construction project broke ground in February 2011 in Aberdeen and construction of the US$586.6 million SR 520 floating bridge and landings project began in spring 2012.
