November 2, 2000

New span bridges the past

The new Novelty Bridge over the Snoqualmie River along Northeast 124th Street has received attention for its innovative incorporation of public art into the bridge design. But, for those who worked to build the bridge, the true innovation is that it all came together in less than seven months.

Photos courtesy of Wilder Construction The old Novelty Bridge was lifted off its trestle by two cranes. For more pictures, click here.

"The county's original schedule was an 18-month schedule," said Mike Bell, project engineer for Wilder Construction, the job's general contractor. "That was a little more reasonable for the quantity of work."

The first Novelty Bridge was built in 1909 with timber beams and without a thought to supporting motorized traffic. The wooden deck was suspended about 50 feet above the water to allow for barges to pass underneath.

Within 10 years, the wooden bridge became decrepit and obsolete, leading to the county's first reconstruction of the span in 1919. A new steel arch bridge was built in the same spot, with 60 tons of steel and two 10-foot lanes.

But the second bridge also became obsolete. After 80 years, the bridge was ill-equipped to handle bigger cars and heavier traffic. In 1997, the King County Department of Transportation began a study into constructing the third incarnation of the Novelty Bridge.

The decision was made to close the route, demolish the old bridge and construct a new one in its place.

Bob Lee, senior engineer for the King County Department of Transportation, said creating a detour was the only real option for bridge construction. Building a temporary bridge would require more right-of-way than was available and would have more impact on the environment. "You would get into some additional permitting problems with that," Lee said.

But residents responded harshly to the idea of closing the major traffic route for more than a year. "The folks in Duvall and the surrounding communities didn't like that too well," Lee said.

A worker forms girder stops for the new bridge.

As a compromise, the county and the project design team condensed the project into one seven-month construction season. Bids for construction called for the accelerated schedule, with severe penalties for taking too long and an ample bonus for finishing early.

Though some had their doubts the project could be finished that quickly, several contractors stepped up to the task. Wilder Construction was awarded the contract for construction of the $10.8 million project in September 1999, giving it six months to prepare for the scheduled March 2000 start date.

"It did help that the contract for this project was let this time last year," Bell said. "It provided us a few months to get a jump on the project."

Several measures were taken to limit the environmental impact of removing the old bridge. In the past, bridges like this were removed by dropping large pieces into the water where they were later retrieved and hauled away. Now, restrictions under the Endangered Species Act severely limit work that occurs in the water.

The old 150,000-pound steel bridge was removed using a crane on each side. "We grabbed on to each end of the truss and walked it off the trestle," Bell said. Wilder Construction had to be careful to prevent chips of lead paint, typically used on bridges built in the 1920s, from falling into the water. "Everything we did over the water had to be fully contained. We couldn't let anything fall into the river."

From the start, crews put in 60 to 80 hours a week on the project. "It was extremely long hours and long weeks for seven months," Bell said. Work went on 12 to 14 hours a day, seven days a week. "We just went full bore for seven months until the road was opened."

The going wasn't always smooth for the highly scrutinized project. "We had an unusual summertime flood," Bell said. A Class 1 flood on the Snoqualmie River impacted the large piers next to the river, pushing the project back by five days. "That was critical activity ... it means you have to make it up with five more days of Saturday-Sunday work or evening work."

Flood waters weren't the only challenge for Wilder. Right away, workers ran into a surprise left by builders of the first bridge. "When they built the second bridge, they decided they didn't want to put the old footings on the new footings," Bell said. The new bridge was constructed just to the side of the old bridge and the old timber pilings were left in place. For the third bridge, "They put it right back in the place where the first footing was."

Bell said dealing with the 90-year-old timbers proved to be a challenge. "There were many of them, 40 to 50 feet in the ground," he said. They had to be removed or driven-through in order to put the new pilings in the right place.

Soil stability was another issue, Lee said. "When we were doing this work, the riverbank became unstable," he said. "We had to get the design consultant and geotechnical consultant together and find out a way to continue on. That was something unforeseen."

The new Novelty Bridge spans the Snoqualmie River near Duvall.

It was Wilder's good relationship with King County, Bell says, that helped it overcome many obstacles. "We felt like they were very responsive with issues that came up," he said. Credit also goes to the design consultant Hans Saxer with engineer Parsons Brinckerhoff Quade & Douglas, and the more than 25 subcontractors and suppliers working on the project.

"It was everyone's number one priority to get this thing done and open early," Bell said.

Through it all, Wilder Construction was able to maintain its work schedule, giving the company the $150,000 bonus guaranteed for an early finish. Bell said so much effort and overtime was invested in the project, "We had to get that bonus. We knew very early, half-way through, that we were going to finish early, simply because we had to."

As the owner representative for King County, Lee said he'd never worked with Wilder Construction before this project. "It didn't take too long to figure out that these guys were on top of this. My confidence level was really high that they would be able to finish this project in the time frame that we had set out," he said. "Professionalism and planning on Wilder's part made this whole thing possible."

The new Novelty Bridge opened to traffic on Oct. 15, about 20 days ahead of schedule.

Related Stories:

• Novel approach to bridge design  10-26-2000
  

Previous columns:

• Constructive education, 10-26-2000
• New furniture line departs from the norm, 10-19-2000
• Green shingles may be no match for gray weather, 10-12-2000
• Builders, counties partner for green homes, 10-05-2000
• Modular construction goes to new heights, 09-28-2000
• Affordable housing to be studied at conference, 09-21-2000
• County trying to curb construction waste, 09-14-2000
• Nuprecon expanding its services and markets, 09-07-2000