Constructing the full State Route 520 corridor from Interstate 5 to Redmond, including a new floating bridge and six-lane highway, is estimated to cost $522 million less than the 2009 legislative budget cap, the Washington State Department of Transportation said Thursday, citing a good bid environment and other factors.

WSDOT finalized documents Thursday for a $300 million federal loan that will fund design and construction of the next portion of the SR 520 project – a westbound bridge between the west-end landing of the new floating bridge and Montlake.

In addition, Transportation Secretary Paula Hammond has instituted personnel and organizational changes for the pontoon construction project to ensure WSDOT has the strongest project delivery team, improved coordination, and stronger oversight of the construction contract. Hammond has also re-convened an expert review panel to conduct additional analysis of pontoon design, repairs and construction management processes.

The organizational changes come as a result of a thorough internal review, ordered by Hammond, of the first cycle of pontoon construction in Aberdeen to fully understand the cause of concrete spalling and more-than-expected cracking. WSDOT’s pontoon design included an error in the post-tensioning duct alignment that is determined to have caused the spalling in one pontoon during tensioning, making repairs necessary. The expert review panel was brought in immediately to evaluate the pontoon cracking and spalling repair and design modifications.

These issues that occurred during the first cycle will likely lead to additional, yet-to-be-determined costs for repairs and schedule delays under discussion between the state and its pontoon and bridge-replacement contractors. Negotiations will take place over the next few months.

The changes within WSDOT will strengthen the delivery team and construction oversight by:

• Relocating bridge design technical advisers for better design coordination.

• Adding additional contract management staff at the Aberdeen pontoon-construction site.

• Adding up to six new quality verification staff in Aberdeen.

• Engaging a short-term claims consultant to help WSDOT assess cost and schedule impacts.

“The good news is that, despite some challenges in constructing these first six of 77 pontoons, we can be confident the pontoons will meet our standards for quality and safety when completed,” Hammond said. “We won’t accept the pontoons from our contractor until we are satisfied they meet contract specification.”

Hammond said the department remains committed to transparency and accountability with taxpayer dollars, replacing SR 520 as quickly as possible, and treating its contractors fairly as responsibility and liability with pontoon design and construction are sorted out.

The remaining budget for the SR 520 projects includes funds to address potential risks during construction. No new funds will be requested from the Legislature.

Program costs

The lower overall program costs are largely the result of a good bidding environment for the pontoon, Eastside, and floating bridge and landings projects, retired risk elements with the completion of the environmental review process, and advanced design on the westside project between Lake Washington and I-5. The updated estimated cost for the 12.8-mile corridor is $4.128 billion, compared with the legislative budget cap of $4.65 billion. With the new federal loan, the unfunded portion of the program is $1.4 billion, down from an estimated $2 billion in 2010.

This new cost estimate is based on the final environmental impact statement and does not reflect potential design modifications being discussed through the Seattle community design process. WSDOT will continue to refine cost estimates based on public feedback on design elements such as the Portage Bay Bridge.

“While bids are coming in lower, we are still accounting for risks so that we are prepared for unexpected issues that can arise during construction,” said SR 520 Program Director Julie Meredith. “We are on track to deliver a new floating bridge that will last 75 years or more. We look forward to finalizing the westside design and cost estimate in the coming year so we are ready to complete the project when funding becomes available.”

TIFIA loan

A new federal TIFIA loan (Transportation Infrastructure Finance and Innovation Act), secured Thursday in Washington, D.C., will fund construction of the north side of the west approach bridge that connects the new floating bridge to land. This will avoid reliance on the existing west approach structure that could be damaged in the event of an earthquake. The new bridge will provide three travel lanes, including one HOV and transit lane and two general-purpose lanes, and connect the regional bicycle/pedestrian path to Montlake. Construction will begin in 2014 and is expected to be complete in 2016.

“With federal funding for state highway projects in short supply, WSDOT is pleased to secure this highly-competitive, low-interest federal loan,” Hammond said. “With this funding, we will continue to make progress on replacing the most vulnerable structures in the SR 520 corridor.”