The Atkinson team delivering the new 70th Avenue East Bridge reached a significant project milestone this weekend with the successful installation of ten giant girders that span I-5 and form the support of the new bridge deck in Fife, Washington.
The 70th Avenue Bridge project is part of WSDOT’s effort to complete SR-167 and improve connections to I-5 and the Port of Tacoma. The new bridge, which features four lanes and a 12-foot wide path for pedestrians and bicycles, replaces an old two-lane bridge.
Safely setting the massive bridge girders, which measure 220-feet-long and weigh 231,000 pounds, required a complete closure of I-5 over two consecutive nights.
The extreme length of the girders allowed Atkinson to complete this operation in 18 hours over two days.
“Shorter girders would have required us to widen I-5 and build columns in the median – work that would have brought prolonged lane closures,” said Laura Newborn, communications manager at the Washington State Department of Transportation. “The longer girders only required one weekend to install.”
The girders, which are among the longest precast concrete girders ever made, were loaded individually onto a 250-foot-long truck at Concrete Technology Corp. in Tacoma, where they were fabricated. They were transported five miles during the night to the bridge site.
Cranes stationed near southbound and on northbound I-5 then guided each of the girders to their predetermined spot.
“This was an extremely technical operation,” said Brandon Dully, vice president at Atkinson Construction. “Our ultimate goal was to ensure that we executed the work according to our plan and did so safely. It took everyone – Atkinson, our hard working crews, WSDOT, and our project partners working together to ensure we set these girders successfully.”
With this milestone complete, the Atkinson team will shift their focus to completing the bridge deck and bridge approaches to open to traffic in the summer of 2021.