[UPDATE 11/30/11: We added some great new photos of the actual girder installation from the night of Nov. 20th, courtesy Brett Fish – scroll down to see those.]
The Sylvester Road Bridge Project is “just about at the half way point” of construction, with 12 segments of new concrete girders installed recently, according to the King County Department of Transportation.
The old bridge, which was 80 years old and in bad condition, has been totally demolished, and the new one is taking shape, with four new girder lines in place that will support the new structure.
“Each girder line includes three girder segments that eventually get ‘closed’ together with concrete and rebar above the temporary shoring towers, then eventually tensioned to final position,” said Linda Thielke, from the King County Department of Transportation.
Thielke adds that the new bridge is scheduled to be completed in mid-February or early March 2012, but weather may delay concrete deck pouring, curing and treating.
“So far the project is on budget and the billing is going smoothly,” she said.
The total budget for replacing the bridge is $3.7 million, which covers the cost of engineering, environmental permitting, public involvement, agency coordination, right-of-way, construction, utility coordination, and construction administration engineering.
Recent construction activities include:
- Old bridge demolished
- New bridge drilled shaft substructure foundation completed
- 2 new bridge abutment and wing wall supports completed above drilled shafts
- 2 temporary shoring towers for new bridge girder erection completed
- All 12 segments of the new concrete bridge girders were launched on Nov. 19 and 20 via cranes
Ongoing and future activities:
- Contractor preparing to place temporary form work to complete the concrete girder diaphragms, new concrete bridge deck, concrete girder closure pour and tensioning of girders
- After final position and tension is achieved, temporary shoring towers will be removed
The final bridge will be a 220-foot long single-span concrete girder structure that is slightly wider than the old bridge, with two traffic lanes and a five-foot wide sidewalk. It will look somewhat similar to the old bridge.
“The bridge itself is a beam bridge, but the concrete beams are prestressed,” added Ron Laiminger, a local resident we met while checking the bridge out in person last week.
For more information, visit the county’s website here.
Here are some photos of the bridge in its recent/current state:
ADDED 11/30/11: Here are some additional photos, showing the actual installation of the girders on the night of Nov. 20th, courtesy Brett Fish, who adds:
The crane in the foreground lifts the giant concrete spans off the flatbed trucks, delicately swings them around to a pad where the second crane is attached to the far end.
Both cranes ever so gently lift the span into place like a delicate ballet dance.
Each of the 12 spans took a little over an hour to place.