High Street Bridge

The High Street Bridge is a double-leaf bascule drawbridge spanning 296 feet of the Oakland Estuary in the San Francisco Bay Area, California, United States. It links the cities of Oakland and Alameda. The bridge is opened approximately 1,400 times a year. The bridge carries an average of 26,000 vehicles per year. The bridge was built when the Oakland Estuary was trenched, converting Alameda from a peninsula to an island.

High Street Bridge
Aerial view in 2010
Coordinates37.7645°N 122.2250°W / 37.7645; -122.2250
CarriesCars and trucks on High Street
CrossesOakland Estuary
LocaleSan Francisco Bay Area
Characteristics
DesignDouble-leaf bascule
MaterialSteel
Total length250 ft (76 m)
Width37 ft (11 m) overall
24 ft (7.3 m) roadway
6 ft (1.8 m) sidewalk
Clearance above15 ft 6 in (4.72 m)
Clearance below14 ft 6 in (4.42 m) (high tide)
21 ft (6.4 m) (low tide)
No. of lanes2
History
Constructed byHarrison Bridge Company
Opened1894, December 1939
Rebuilt1901, 1939
Statistics
Daily traffic30,000
High Street Bridge
Location in Oakland, California
High Street Bridge
High Street Bridge (San Francisco Bay Area)
High Street Bridge
High Street Bridge (California)

The High Street Bridge is one of the four bridges and two tunnels that allow access to Alameda.

History
The bridge in 2003

The estuary was originally spanned by an iron swing bridge, completed in 1894 by the Harrison Bridge Company for $24,747. In May 1901 a fire destroyed the swing span and part of the approaches, which were rebuilt the following year. Three bridges were built by the federal government in 1901 at High Street (road), Park Street (road), and Fruitvale Avenue (combined road and rail) in exchange for permission and rights-of-way to dredge the channel between San Antonio Creek and San Leandro Bay.[1]

After the three bridges were completed, they were left closed to allow road and rail traffic to pass, but never opened for marine traffic.[2][3] The northern approach to the High Street Bridge was destroyed by a fire in May 1909, which also damaged the bridge; repairs were performed late in 1909.[2][4][5] After pressure was applied by Senator George Clement Perkins and Congressman Joseph R. Knowland,[6] the federal government turned the bridges over to Alameda County in 1910, conditioned on the county assuming responsibility for maintenance, staffing, and operation.[3]

The present bridge was designed by the County of Alameda Surveyors Office and constructed under the Federal WPA Program in 1939 at a cost of $750,000.[1] It opened in December 1939.[7]

The bascule bridge was modernized in 1981 and 1996. The 1981 project included upgrades to electrical systems and motors; the 1996 project completely repainted the bridge, removing over 25,000 pounds (11,000 kg) of lead-based paint.[1]

Design

The bridge normally opens both leaves to 45°, which accommodates most marine traffic; the maximum opening for each leaf is 76°.[1] It is designed to safely operate in wind speeds of up to 30 miles per hour (48 km/h).[1]

Each leaf may be operated independently, allowing marine traffic to pass in the event that one leaf is inoperable.[1] Each leaf has a 75-horsepower (56 kW) main motor using electricity from Alameda Municipal Power, and a 5-horsepower (3.7 kW) emergency motor for each leaf is powered from Pacific Gas and Electric; using counterweights, full operation is possible using emergency power.[1]

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References
  1. "High Street Bridge". ACPWA.org. Alameda County Public Works Agency. Retrieved 13 November 2012.
  2. "Government May Give Canal Bridges to City". San Francisco Call. 106 (176). 23 November 1909. Retrieved 2 May 2017.
  3. "Bridges will be open to traffic". San Francisco Call. 108 (86). 25 August 1910. Retrieved 2 May 2017.
  4. "High Street Bridge will be repaired". San Francisco Call. 106 (50). 20 July 1909. Retrieved 2 May 2017.
  5. "High Street Bridge is being repaired". San Francisco Call. 106 (164). 11 November 1909. Retrieved 2 May 2017.
  6. "Urge Congress to Deliver Bridges". San Francisco Call. 107 (28). 28 December 1909. Retrieved 2 May 2017.
  7. "Henderson's Kin Designs New Bridge". Healdsburg Tribune, Enterprise and Scimitar. 11 December 1939. Retrieved 2 May 2017.
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