CRC begins testing ground near I-5 Bridge
$4.22 million project tries out foundations, techniques, soils as planners aim to determine how to put new span on firm footing
Monday, April 2, 2012
PORTLAND — Huge equipment and construction next to the Interstate 5 Bridge doesn’t mean its planned replacement — the $3.5 billion Columbia River Crossing — will break ground anytime soon. But project officials hope on-the-ground testing will answer some key questions before it does.
Crews recently started preliminary work that will test construction techniques, foundations and bridge supports for the new span. The job began in earnest last week, with pile driving on the Oregon side of the Columbia River. The idea is to clarify how well the soil will hold up under different scenarios as CRC officials finalize their plans for the bridge itself, said lead project engineer Frank Green.
“It’s becoming a lot more commonplace to use this kind of program,” Green said.
Workers are using two main techniques as part of the test. The first is pile driving, which pounds long, cylindrical steel columns into the ground to provide bridge support. The other is drilled shafts, which create deep cylindrical holes into which concrete is poured to form foundations.
Throughout the process, nine sensors will measure noise and vibration near work areas.
The job will put five piles into the ground on Hayden Island, each in two sections totaling 140 feet. Drilled shafts will go as far as 260 feet into the ground.
The work is starting on Hayden Island using both methods. Contractors will move the work to Vancouver by this summer, drilling shafts just west of the freeway near the state Highway 14 interchange. But pile driving won’t be tested on the Washington side of the river. That’s because the technique has already been used and proven in other projects on Washington soil, Green said. Hayden Island sits on a different soil composition, he said.
“It’s trying to really allow us to move forward with bettering our design but also keeping the options open,” Green said.
The CRC awarded a $4.22 million contract for the testing to Spokane-based Max J. Kuney Co. last December. Money for that work has already been allocated from the states of Washington and Oregon and federal funds, said CRC spokeswoman Anne Pressentin.
Work was originally supposed to happen at three locations. But when the U.S. Army Corps of Engineers balked at plans for drilling near Portland’s Marine Drive — near existing river levees — planners decided to just go ahead with the other two sites to expedite the testing, Pressentin said. The CRC still may work with the corps to carry out drilling and pile driving at Marine Drive when the project gets closer to construction, she said.
That schedule, however, remains uncertain. Recent plans had called for project construction to start in 2013, but CRC leaders have indicated that may be delayed until 2014. The project hasn’t secured a firm funding commitment from either state. And a recent spat with the U.S. Coast Guard over the new bridge’s planned height threw a new wrench into an already uncertain timeline.
The CRC would replace the I-5 Bridge, rebuild the freeway on both sides of the Columbia River and extend light rail into downtown Vancouver. The project has spent more than $140 million in planning so far.
This spring’s preliminary work represents the second round of foundation testing in as many years. In early 2011, crews drove pilings into the Columbia River itself.
On Monday, the Hayden Island site hummed with activity as freeway traffic sped by. Several sections of steel pilings were already in the ground, with others lying ready for their turn. One worker welded another cylinder as crews completed maintenance work on the pile driver.
The testing project is scheduled for completion in July.