Tuesday, September 10, 2013
|Photo from City of Shoreline website|
Hidden Lake Bridge
Hidden Lake Bridge is functionally obsolete
The Hidden Lake Bridge was originally constructed in 1931 and is a two lane, 310 foot long concrete bridge built into the side of a hill along a ravine above Hidden Lake. The bridge was retrofitted in 1996 to address several deficiencies.
Despite these measures, the bridge is classified as functionally obsolete due to the narrow deck width and has experienced deterioration of several components. Due to these deficiencies, the bridge is currently rated at 51.3 (bridges less than 50 should be considered for replacement).
|The Bridge is where the map says 10th Ave NW,|
north of Innis Arden Way
The bridge as it currently exists is in poor condition. Many concrete elements are spalled or cracked, exposing reinforcing steel. The bridge railing is in poor condition and presents a hazard for vehicles due to the steep slopes. There are signs of soil sloughing around the foundation of the bridge. One footing has been exposed. The bridge was reinforced with wood supports to retain some of the soil and prevent cave-ins at the sidewalk above. A load rating determination has been recommended by King County to reassess the load carrying capacity of the bridge.
The existing bridge is currently deteriorating and is in need of either rehabilitation or replacement. The currently bridge rating of 51.3 (out of a rating of 100) meets the threshold for rehabilitation (a minimum score of 80 is needed) and borders on replacement (a minimum score of 50 is needed).
Current available funds will support the predesign phase of this project with the following work to be done:
- The load carrying capacity of the bridge will be evaluated
- A revised bridge rating will be determined
- A recommended option to address the bridges deficiencies
- An engineer’s estimate for construction
- Prepare grant applications for design and construction of the recommended alternative
Continued work beyond the predesign phase is dependent on additional funding made available. Once full funding is secured, the recommended alternative will be designed and constructed.