Thurston County Public Works crews together with staff from WSDOT made quick work of the installation of WSDOT's Bailey bridge over the L-4 Bridge crossing this week, allowing the county to re-open the bridge to most vehicles a few days earlier than expected. The L-4 crossing on Littlerock Road SW will re-open for passenger vehicles, buses and emergency vehicles at 10 a.m. on Saturday, March 22.
On Friday, March 14, Thurston County Commissioners approved an agreement with the Washington State Department of Transportation for use of a modular temporary bridge structure called a Bailey bridge at the L-4 Bridge crossing on Littlerock Road SW. The Bailey bridge will be one lane wide, and temporary traffic signals will alternate and allow passenger vehicles, buses and emergency vehicles to travel northbound and southbound safely. Heavy trucks will still need to use the detour route. The temporary L-4 crossing will remain open until construction of the new permanent bridge begins later this summer. Construction is expected to take about four to five months, and county staff members plan to complete the project before the end of 2014.
"Our friends at WSDOT have been a huge help," said Donavan Willcutt, Director of Thurston County Public Works. "This Bailey bridge is really a slice of engineering genius, and the crews worked so fast and so well together, they had it installed and ready to go in no time."
Willcutt continued, "Everyone in the Public Works Department has done a tremendous job these last few weeks—detecting the problems with the bridge, working with the community, combing over the options, working quickly with WSDOT to get this Bailey bridge in place—I can't thank my team enough."
The L-4 Bridge on Littlerock Road SW located between 110th Avenue SW and 93rd Avenue SW was first closed on Monday, January 27 after structural deficiencies were discovered. Engineers found the soil under the center pier of the 1950s vintage bridge had been washed away by scour, making the pier unstable. The center pier had developed a significant crack and the bridge deck was sagging in several places, and engineers determined that the bridge was in danger of collapsing with the weight and stress of continued vehicle traffic. The bridge was closed to protect the public's safety, and crews immediately began work on temporary repairs to the bridge structure.
The bridge re-opened briefly on February 19 to passenger vehicles after work was done to temporarily stabilize the pier and the bridge deck enough to support light vehicles. Despite signs limiting speeds and restricting heavy vehicles from the bridge, several heavy trucks and speeding vehicles were seen using the bridge. Because the temporary fixes were not designed to withstand the stress and weight of heavy trucks, crews were forced to close the bridge again less than a day later to prevent any further damage to the bridge and protect the public's safety.
Repair work on the nearby L-5 Bridge will continue next week. Engineers recently found scour under one of the support piers and some cracking in the bridge structure that is similar to the damage on the L-4 Bridge, but not as severe. Traffic is restricted to one lane while crews complete the repair work. Get connected with Thurston County Public Works.
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