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The SR520 Montlake EB Bridge completes the updated bridge portion of SR520 over Lake Washington and is the companion project of the westbound bridge project of 2015. The project consists of a 41-span bridge over Lake Washington, a lid over SR520 on the project’s west side, and a pedestrian bridge. Notably, this project embraced some accelerated bridge construction concepts by utilizing precast columns and caps in addition to girders. To comply with safety requirements the lid girders were customized to add ½” of concrete cover for fire protection.
Accelerated Bridge Construction – Precast piles, pile caps, and girders for faster in-field construction.
Custom Lid Girders with extra concrete cover for fire protection – Lid girders added ½” extra concrete cover to bottom flange and web of girders for extra fire protection rating.
High Performance Girders – This project is designed to support lightrail in the future. Several girders of each span were designed with extra stand and rebar in order to accommodate the light rail loads in the future.
Lid:
50pc WF58FPG girders (longest = 92.47’, Heaviest = 98,200 lbs.)
130pc WF74FPG girders (longest = 118.48’, Heaviest = 149,300 lbs.)
2pc UF58G4 Tub girders (longest = 92.54’, Heaviest = 132,700 lbs.)
2pc UF72G4 Tub girders (longest = 118.60’, Heaviest = 200,000 lbs.)
24pc 30” Voided Slabs (longest = 41.12’, Heaviest = 51,600 lbs.)
Pedestrian Land Bridge:
30pc WF66G girders (longest = 109.34’, Heaviest = 112,900 lbs.)
Direct Access Ramp:
5pc WF58G girders (longest = 107.84’, Heaviest = 105,300 lbs.)
2pc U58G4 Tub girders (longest = 111.00’, Heaviest = 154,600 lbs.)
SR 520 East Bound Bridge:
40pc UF72G4 Tub girders (longest = 147.05’, Heaviest = 239,100 lbs.)
185pc WF74G girders (longest = 148.37’, Heaviest = 162,100 lbs.)
80pc Precast Columns (longest = 40.27’, Heaviest = 131,800 lbs.)
43pc Precast Pile Caps (largest = 79.5’ x 6’ x 23.5’, Heaviest = 149,500 lbs.)
