Construction of La.'s Interstate 10 Twin Span bridges is state's largest public works project...

At $803 million, construction of the new Interstate 10 Twin Span bridges is the largest public works project ever let by the Louisiana Department of Transportation and Development.

Construction of the new bridges will offer a benchmark for design standards and teamwork and be symbolic

"I feel honored to be here," said Bill Moulton, project superintendent for Boh Bros. Construction of New Orleans. "Completing this project will be the biggest challenge of my lifetime."

From the emergency repair and maintenance of existing bridges to design and construction of new ones, these have been unusual projects.

The existing spans were heavily damaged when Hurricane Katrina's storm surge lifted the bridge decks off 58 spans and misaligned 473 more.

In spite of a scattered work force and loss of equipment and resources, Boh Bros. performed emergency repairs on the bridge and opened four lanes of traffic by Jan. 6, 2006.

Richard Capka, acting administrator for the Federal Highway Administration, lauded contractors and heralded the project as a "visual metaphor" for the region's recovery. At the September groundbreaking for the new bridges, Gov. Kathleen Babineaux Blanco said the project is "a sure sign that we are headed down the road to recovery in a very big way."

A fast-paced schedule is again a factor in Boh's $379-million contract to construct roughly 4.5 miles of the low-level portions of the new spans. The westbound span is scheduled for completion in 2009 and the eastbound in 2011.

"For the first contract, we have a maximum bonus incentive of $4.5 million," said G.J. Schexnayder, project manager for Boh. "That means we would have to finish by December 2008."

Volkert Construction Services Inc. of New Orleans, which is performing construction, engineering and inspection services for the DOTD, also worked with Boh Bros. on the emergency bridge repairs. "During that time, we developed a relationship with Boh Bros., and we are committed to a common goal - opening the bridge early and having it meet all the specifications," said John Horn, vice president and project manager.

Volkert's role on the project represents another first for the DOTD, Horn said. "They don't typically contract out engineering services but do it all in house."

Since no bridge design standards existed for resisting the wind and wave combination that damaged the twin spans, the DOTD set a precedent involving elevated height, weather resistant concrete and reinforced attachments to prevent the deck uplift from storm surge on Lake Pontchartrain.

"If it had been about 10 feet higher, it most likely would not have toppled as it did," said Hossein Ghara, DOTD bridge design administrator. The new bridge is being constructed 300 feet south of the existing one and will be 21 feet higher at 30 feet with three lanes of traffic on each side. The design also stipulates larger foundations and more redundant pilings to better resist ship impact.

"The bridge will also be built entirely of higher-performance, high-strength concrete that is more resistant to saltwater corrosion and wind and water loads," Ghara said.

Shear keys, supports that prevent lateral movement of girders, have also been added to prevent any displacement.

"This is one sturdy bridge," Schexnayder said. "If a storm surge comes through that is big enough and tall enough to knock this bridge down, there will be nothing left on the other side of the lake to get to."

By April, Boh Bros. will drive pilings from both sides of the lake, working toward the middle. The joint venture of Traylor Bros. Inc., Kiewit Southern Co. and Massman Construction Co. won the $166.6-million contract to construct the "hump" portion of the bridges, a roughly 1-mile, 80-foot elevated section with 200-foot horizontal and 73-foot vertical navigational channel clearance.

The joint venture work order was issued Jan. 25 and key staffers are being hired, offices are being located on site, and subcontracts and purchase orders being signed, said Scott Armstrong, project manager.

"We won't start any physical work until April when we start driving production piles," Armstrong said.