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High Street Bridge

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Location:
High Street Bridge is located on the Oakland Estuary (Oakland Tidal Canal), which is located in Alameda County, California. The bridge spans the cities of Oakland and Alameda. The Oakland Estuary is a navigable waterway with access to the San Francisco and San Leandro Bays.

See Location Map Page

Built:
High Street Bridge was engineered and built in 1939 by the Federal Government and the County of Alameda. It officially opened in December 1939 at a cost of $750,000.  High Street Bridge was part of the large Public Works Projects of the 1930’s that also included the Golden Gate and Oakland/San Francisco Bay Bridges.

Owner:
County of Alameda, California owns and maintains the bridge. The bridge is the responsibility of the Alameda County Department of Public Works. The United States Coast Guard regulates the draw bridge.

Type:
High Street Bridge is a double leaf bascule draw bridge.

Operation:
The High Street Bridge is operational year around 7 days a week, 24 Hours a day. There are two vessel restriction periods. These restrictions are 7:30 a.m. to 8:30 a.m. and 3:45 p.m. to 5:45 p.m. Monday through Friday.  There are no vessel restrictions on weekends or holidays.

Note:  Vessels can transit the draw during closure hours if advance notice is given, an emergency, or tidal conditions dictate transit during closure hoursYou must call the bridge office to arrange an opening during closure hour's (510) 535-0475.

The bridge is manned by a alternating four-person crew.  High Street Bridge is equipped with a Marine Radio, the working channel in the San Francisco Bay Area is Channel 9. Vessels can also gain a bridge opening by using a horn. The signal is a long blast followed by a short blast.

Maintenance:
The Alameda County Department of Public Works provides preventive maintenance and repairs to the bridge.

Vessel and Vehicle Statistics:

Vessel Traffic (Bridge Openings)

Opening Per Year 1,400
Total Vessels 1,700
Barges 615

Vehicle Traffic

Northbound 12,400 per day
Southbound  13,600 per day
Total Vehicle Traffic 26,000 per day
Busiest Hour North Bound
8:00 a.m. to 9:00 a.m.
1121 vehicles
Busiest Hour South Bound
5:00 p.m. to 6:00 p.m.
1083 vehicles
Slowest Hour North Bound
4:00 a.m. to 5:00 a.m.
34 vehicles
Slowest Hour South Bound
4:00 a.m. to 5:00 a.m.
19 vehicles

Bridge Statistics:

Vertical Clearance MLLW (Low Tide) 21 Feet
Vertical Clearance MHHW (High Tide) 14 Feet 6 inches
Clearance Between Fenders 200 Feet
Maximum Vehicle Load Limit 40 Tons
Bridge Height Restriction for Vehicles 15 Feet 6 inches
Bridge Width 37 Feet
Bridge Length 250 Feet
Width of Roadway 24 feet
Width of Traffic lanes 12 feet
Pedestrian Sidewalk's 6 Feet

Information & History:

High Street Bridge spans the Oakland Estuary and is about 250 feet in length. High Street Bridge is a double leaf bascule bridge. Under normal operating conditions both leafs are used. Each leaf of the bridge can be operated independently. This gives the operator flexibility and helps keep the channel open for vessels in case one leaf is down for repairs.

Main power to the bridge is supplied by the Bureau of Electricity (City of Alameda).  The Power Cable is contained in a submarine cable that is buried on the estuary bottom.  The power cable is fed to the Bridge Tower located on the Oakland side of the Bridge The Alameda feed provides the power to run both or one leaf of the bridge under full power using the 75-hp main motors located in each machinery room. Emergency power is supplied by Pacific Gas and Electric (PG&E).

Emergency power can operate both or one leaf of the bridge using the emergency drive system utilizing a 5-hp motor.   When the bridge is running under emergency power it travels much slower than normal operating power.  There is also the capability to run the bridge using a portable generator in case of extreme emergencies.  The Oakland leaf only is operable under these conditions.

There are two operator towers, the main operational tower is on the Oakland side of the bridge. The secondary tower in Alameda is a backup, and can only operate the Alameda Side of the bridge.   Four gates and two cable barriers secure the bridge for vessel openings.

High Street Bridge has two machinery rooms one for each leaf. Each leaf is powered by a 75-hp main motor and 5-hp backup motor. One service brake in each machinery room supplies the braking power.   Emergency braking is supplied by a hydraulic brake system in case the electrical brake system fails.

If you're wondering how thousands of pound of steel can be lifted by 5 hp, its done by almost perfect counterbalancing. A huge counterweight supplies the balancing needed for the 100 plus foot long section of bridge. The Counterweight Pit is 40 feet below the roadway and when you stand on the pit floor it's only concrete that separates you from the water.  A pump in the pit floor keeps the pit from filling up with water.

A modernization project in 1981 updated many of the electrical and mechanical systems of the bridge. New control consoles, leaf drive systems, power distribution, underwater cables, air buffers, roadway and approach lighting, and much more was completed under the modernization. According to many operators, it was a vast improvement over the original equipment. This equipment is in use today. High Street Bridge is one of the county's most reliable Draw bridges.

Each leaf of the bridge can open to a 76-degree position, this is considered a full opening. A normal opening is 45-degrees and can accommodate 95% of vessel traffic. With a full opening the bridge can accommodate almost any vessel. The main limiting factor would be vessel width and the depth of the channel. The bridge can operate safely under wind conditions reaching 30 mph. When operating the bridge with over 30-mph wind conditions extreme caution must be used.

In 1996 another modernization project was completed. The High Street Bridge was completely stripped of all primer and paint. This was a difficult project as it was necessary to contain the lead-based paint and primer from entering the waterway and the San Francisco Bay. The bridge was completely enclosed in a tent like structure and huge vacuum sucked up all paint debris.  While High Street Bridge had many touch-up paint jobs over the years this was the first complete paint job in 56 years.

Over 25,000 pounds of debris was removed from the bridge during the project. This changed the operation of the bridge and adjustments had to made to the counterbalancing to make the bridge operate correctly. In addition to the paint job, new energy efficient roadway and approach way lights were installed and closed circuit monitors and cameras were installed to aid the in the operation of the bridge.

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