Already plagued with problems, floating-bridge construction in Seattle will now cost tens of millions of dollars more after state transportation officials conceded that their own design mistakes were to blame for cracked concrete.
The Washington State Department of Transportation said Tuesday (Feb. 26) that its own design mistakes may now cost upwards of $100 million to fix.
The state chose to design the pontoons for the SR 520 bridge on a fast track, rather than make contractors responsible for them, and inspections have now revealed that pre-existing cracks on the pontoons have grown worse over the winter.
After nearly 50 years in service, the SR 520 bridge's floating pontoons are nearing the end of their life. Construction on the new floating structure started in May 2012 and has been plagued with problems ever since.
In January 2011, WSDOT awarded a $586 million design-build contract to Kiewit-General-Mason Joint Venture to build the concrete pontoons and a six-lane bridge, among other things.
Once completed, the SR 520 bridge roadway will provide a seamless transition from the floating bridge to fixed bridges off the shore and on land, connecting Seattle and Medina.
'Failures' by Employees, Management
Designing the pontoons itself was WSDOT's strategy to attract lower bids and get the floating section built by 2014. The winning bid to build the pontoons was $180 million less than the state expected to pay.
The SR 520 program has an established budget that includes a remaining balance of $200 million in risk and contingency. WSDOT and Kiewit are expected to complete negotiations next month on a change order, WSDOT said.
"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."
'Disciplinary Actions' Requested
Hammond requested an internal review to determine if employees or managers had 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."
"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 will be leaving her post on March 8, the Seattle Times reported. Gov. Jay Inslee, seeking a greater emphasis on transit and clean fuels, named Lynn Peterson as the DOT secretary. Peterson is a highway engineer and adviser to Oregon's governor.
Internal Review Findings
The internal review found that in the summer of 2009, as the request for proposal (RFP) was being developed, the Bridge and Structures Office (BSO) "did indicate strongly, several times to SR 520 staff ... that they felt the specifications and plans for the pontoons should be much more developed and prescriptive than what was normally called for in Design-Build."
WSDOT revealed on Tuesday (Feb. 26) that its own design mistakes were to blame for some of the bridge's construction problems.
Then, in August 2009, the BSO delivered its specification requirements to be incorporated into the RFP. The specifications were found to be too rigid to meet Federal Highway Administration Design-Build requirements, and the SR 520 staff and BSO staff were directed to "urgently and quickly revise the specifications so that they would meet FHWA requirements for a Design-Build contract," the internal review found.
Other findings from the internal review included:
Lack of sufficiently complete internal alignment process "led to problems with the pontoon design, definition of design responsibility, RFP suitability, and development and construction implementation of the pontoon design";
Cracking caused by thermal effects "might have been better prevented or minimized if proper thermal controls, as specified in the contract, had been implemented";
Some QA/QC processes were "not understood or agreed upon by BSO, were inadequately implemented and/or documented, or were not carried out properly by the BSO"; and
Changes to the contract were allowed without appropriate approval or contract change documentation.
The report documents dozens of other findings as well as recommendations for WSDOT executives and key managers.
This winter, divers examined four large pontoons on the lake and found cracks on the undersides that had been concealed when the pontoons were sitting in the casting basin.
Similar cracks on the top of the pontoons have grown four to six inches in length since being towed to Seattle in August, said John Reilly, head of an expert review panel that WSDOT formed last year to review causes of cracking and spalling in the first cycle of construction.
Now, the plan is to add post-tensioning from side to side, squeezing the cracks shut, and then injecting them with epoxy as well as possibly applying carbon-fiber patches, said Jeff Carpenter, chief construction engineer for WSDOT.
On Feb. 18, WSDOT made available the expert panel report on phase two of the pontoon construction.
In May 2012, crews found cracking and spalling after completing post-tensioning on a longitudinal pontoon. The problems were repaired by adding reinforcing steel to fix the spalling, replacing concrete, and injecting epoxy to fix the cracks, according to WSDOT.
Once repairs were completed, the first six pontoons were floated out of the casting basin on July 30, 2012. However, an Aug. 22, 2012 inspection found ballast water leaking between two cells in one pontoon and moisture on the inside of an end wall in another.
WSDOT stated that the leak was repaired almost immediately, but "WSDOT and the contractor are continuing to look into the cause of this moisture" found in the end wall.
An expert review panel recommended adjusting the design and position of post-tensioning strands and ducts, but said that repairs were "adequate for structural capacity."
Over the winter, existing cracks grew in size and new cracks were discovered, underwater inspections revealed.
In October 2012, crews began construction on 10 58-foot-tall concrete columns to put on top of one of the two cross pontoons. The new roadway deck will be installed on top of bridge piers before sloping down onto the columns.
KGM inspectors then discovered that one of the concrete columns had too little buffer between the concrete and reinforcing steel, causing project managers to remove and replace the column.
WSDOT later issued a quality assurance update that said crews were removing and replacing one of the 10 concrete columns where the concrete pour failed to meet quality specifications.
When the tube was removed from one column, some of the concrete peeled off with it, and workers found the rebar cage had shifted during the pour, leaving less than the normal 1.5-inch concrete thickness around the rebar, a WSDOT spokesperson said at the time.
"KGM's decision to replace this column at their expense is the appropriate action," said Julie Meredith, SR 520 program director.
In November 2012, crews had completed construction of 345 pre-cast concrete wall panels; KGM rejected nine of them. Three exceeded the contractual limits for cracking, and six were rejected due to a duct alignment issue, WSDOT reported.
The SR 520 bridge sees 115,000 cars per day and has only two lanes in each direction. After nearly 50 years in service, it is nearing the end of its original service life. The bridge's pontoons have become vulnerable to windstorms, and its support columns have become vulnerable to earthquakes.
The new pontoons are designed for a 75-year service life to withstand windstorms up to 89 mph and a 1,000-year earthquake event. The new bridge will provide a six-lane roadway.
This project is the first construction phase of the SR 520 – I-5 to Medina: Bridge Replacement and HOV Project, for which the Washington Stage Legislature has set a program budget of $4.65 billion.
According to WSDOT, the latest jobs report counted 832 jobs directly connected to the pontoon and floating bridge project sites.