Dumbarton Bridge

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Dumbarton Bridge (California)

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The Dumbarton Bridge is the southernmost of the highway bridges across San Francisco Bay in California. Carrying over 81,000 vehicles daily, it is the shortest bridge across San Francisco Bay at 1.63 miles (8,600 ft; 2,620 m). Its eastern end is in Fremont, near Newark in the San Francisco Bay National Wildlife Refuge, and its western end is in Menlo Park. Bridging State Route 84 across the bay, it has three lanes each way and a separated bike/pedestrian lane along its south side. Like the San Mateo Bridge to the north, power lines parallel the bridge.

Contents
1 Tolls
2 Environmental factors
3 History and engineering features
4 Roadway Connections
5 Dumbarton Rail Bridge
6 Hetch Hetchy Aqueduct

Tolls


Tolls are only collected from westbound traffic at the toll plaza on the east side of the bay. Since July 2010, the toll rate for passenger cars is $5. For vehicles with more than two axles, the toll rate is $5 per axle. Drivers may either pay by cash or use the FasTrak electronic toll collection device. There are seven toll lanes at the plaza. During peak traffic hours, the leftmost lane is designated a FasTrak-only HOV lane, allowing carpool vehicles carrying two or more people or motorcycles to pass for a toll of $2.50. The next two leftmost lanes are FasTrak-only lanes for all vehicles, and all other lanes accept both cash and FasTrak. During non-peak hours the HOV lane is open to vehicles carrying only one person, but remains FasTrak-only.

Environmental Factors


When the current bridge was planned in the 1970s, Caltrans conducted extensive environmental research on the aquatic and terrestrial environment. Principal concerns of the public were air pollution and noise pollution impacts, particularly in some residential areas of Menlo Park and East Palo Alto. Studies were conducted to produce contour maps of projected sound levels and carbon monoxide concentrations throughout the western approaches, for each alternative connection scheme.

The area around the bridge is an important ecological area, hosting many species of birds, fish and mammals. The endangered species California clapper rail is known to be present in the western bridge terminus area.

Near the bridge on the Peninsula are Menlo Park’s Bayfront Park, East Palo Alto’s Ravenswood Open Space Preserve, and the Palo Alto Baylands Nature Preserve. An accessible portion of the San Francisco Bay National Wildlife Refuge lies immediately north of the western bridge terminus, where the Ravenswood trail runs.

On both sides of the east end of the bridge are large salt ponds and levee trails belonging to the Don Edwards San Francisco Bay National Wildlife Refuge. The headquarters and visitor center for the refuge is on a hill south of the bridge approach. North of the east end of the bridge is Coyote Hills Regional Park, with its network of trails running over tall hills. North of that is the Alameda Creek Regional Trail from the Bay to Niles Canyon. East of Coyote Hills is Ardenwood Historic Farm, a restored working farm that preserves and displays turn-of-the-century farming methods

History and Engineering Features


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The original vertical-lift span of the Dumbarton Bridge, shown in 1984 shortly before it was demolished

The bridge has never been officially named, but its commonly used name comes from Dumbarton Point, named in 1876 after Dumbarton, Scotland. Built originally to provide a shortcut for traffic originating in San Mateo and Santa Clara counties, the bridge served industrial and residential areas on both sides. The earlier bridge opened on January 17, 1927 and was the first vehicular bridge to cross San Francisco Bay. A portion of this old drawbridge remains as a fishing pier on the east side of the Bay. The original bridge was built with private capital and then purchased by the state for $2.5 million in 1951.

Its age and the two-lane undivided roadway and lift-span led to a replacement bridge, built to the north. This bridge opened in October 1982 as a four-lane, high-level structure. The structure was re-striped to accommodate six lanes on October 18, 1989 in response to the temporary closing of the San Francisco–Oakland Bay Bridge due to the Loma Prieta earthquake, and the permanent widening of the approaches was completed by July 2003. The cost of the complete replacement project was $200 million. The current bridge includes a two-way bicycle and separate pedestrian path on the south-facing side. A 340 ft (104 m) center span provides 85 ft (26 m) of vertical clearance for shipping. The approach spans on both sides of the Bay are of pre-stressed lightweight concrete girders supporting a lightweight concrete deck. The center spans are twin steel trapezoidal girders which also support a lightweight concrete deck. In 1970 the movie Harold and Maude was filmed at the toll plaza and showed Maude speeding and disobeying a police officer.

The center span of the original bridge was demolished in a controlled explosion in September 1984.

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A view from the air, above Palo Alto, looking towards Fremont

Roadway Connections


The bridge is part of State Route 84, and is directly connected to Interstate 880 by a freeway segment north of the Fremont end. There is no freeway connection between U.S. 101 and the southwest end of the Dumbarton Bridge. Motorists must traverse one of three at-grade routes to connect from the Bayshore Freeway to the bridge. These are (from northwest to southeast):

  1. the Bayfront Expressway, a limited-access road linking to U.S. 101 at Marsh Road, Atherton (the official routing of SR 84)
  2. Willow Road (SR 114), an approximately one-mile expressway through east Menlo Park to U.S. 101
  3. University Avenue (SR 109), an arterial road and the main commercial street of East Palo Alto.

The Willow Road and University Avenue junctions with Bayfront Expressway are at-grade intersections controlled by traffic lights; there are two additional controlled intersections at Chilco Road and Marsh Road, and the Marsh Road interchange on U.S. 101 is a parclo. The result is that Bayfront Expressway is frequently congested, and when not congested is often the site of high-speed car crashes. In 2007, prominent author David Halberstam was killed in one such crash at the Willow Road intersection.

Access to I-280 is available via State Route 84 to Woodside Road (as signed) or other arterial routes. There are no cross-Peninsula freeway connections between State Routes 92 and 85 (which is so far south that it technically lies in Silicon Valley and not on the Peninsula). In addition, there are no direct cross-Peninsula arterial routes between State Route 84 and Page Mill Road, a five-mile gap.

Although the present situation has resulted in severe traffic problems on the bridge itself and in Menlo Park and East Palo Alto, Caltrans has been unable to upgrade the relevant portion of Highway 84 to freeway standards for several decades, due to opposition from the cities of Menlo Park, Atherton and Palo Alto. Freeway opponents fear that upgrading Highway 84 will encourage more people to live in southern Alameda County (where housing is more affordable) and commute to jobs in the mid-Peninsula area (where businesses wish to be located in order to be close to Silicon Valley), thus increasing traffic in their neighborhoods to the south and west of U.S. 101.

Bus service across the bridge is provided by the Dumbarton Express, run by a consortium of local transit agencies (SamTrans, AC Transit, VTA and others) which connects to BART at Union City and Caltrain at Palo Alto and California Avenue. AC Transit also runs Transbay buses U (Fremont BART and Amtrak to Stanford) and DA (Ardenwood to Oracle and Facebook headquarters) across the bridge. The free Stanford Marguerite Shuttle also runs buses AE-F and EB across the bridge.

Dumbarton Rail Bridge


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Dumbarton Rail Bridge 2007 (seen from a kayak)

Just to the south of the car bridge lies the Dumbarton Rail Bridge. Built in 1910, the rail bridge has been unused since 1982 and its western approach collapsed in a fire in 1998. When the bridge was in use, boaters would signal the operator, who would start a diesel engine and rotate the bridge to the open position on a large gear. The bridge is now left in the open position as shown. There are plans for a new rail bridge and rehabilitation of the rail line to serve a commuter rail service to connect Union City, Fremont, and Newark to various Peninsula destinations. A successful March 2004 regional transportation ballot measure included funding to rehabilitate the rail bridge for the commuter rail service, but in October 2008 the Metropolitan Transportation Commission transferred $91 million from this project to the BART Warm Springs Extension Project in Fremont.

Hetch Hetchy Aqueduct


Between the Dumbarton Bridge and the Dumbarton Rail Bridge is the Bay crossing of the Hetch Hetchy Aqueduct. The aqueduct rises above ground in Newark at the east side of the Bay, falls below the water’s surface at a pump station in Fremont, re-emerges in the middle of the Bay and then continues above water until it reaches the west side of the Bay at Menlo Park.

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San Mateo–Hayward Bridge

From Wikipedia, the free encyclopedia

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Aerial view of the San Mateo–Hayward Bridge, with Foster City in the foreground

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San Francisco Bay Bridges

San Mateo–Hayward Bridge

The San Mateo–Hayward Bridge (commonly called the San Mateo Bridge) is a bridge crossing the U.S. state of California’s San Francisco Bay, linking the San Francisco Peninsula with the East Bay. The bridge’s western end is in Foster City, a suburb on the eastern edge of San Mateo. The eastern end of the bridge is in Hayward. It is the longest bridge in California and the 25th longest in the world by length. The bridge is owned by the state of California, and is maintained by Caltrans, the state highway agency. Further oversight is provided by the Bay Area Toll Authority.

The bridge is part of State Route 92, whose western terminus is at the town of Half Moon Bay on the Pacific coast. It links Interstate 880 in the East Bay with U.S. Route 101 on the Peninsula. It is roughly parallel to and lies between the San Francisco–Oakland Bay Bridge and the Dumbarton Bridge, and is sometimes used by commuters to avoid traffic delays due to emergencies on those bridges.

Contents
1 History and description
1.1 1929 original bridge
1.2 1967 orthotropic bridge
1.3 Upgrades and repairs
1.3.1 Seismic upgrades (1997–2000)
1.3.2 Widening (2002–2003)
1.3.3 Seismic beam (2010–2012)
1.3.4 Repaving (2015)
1.4 Werder Pier
2 Tolls

History and Description


1929 Original Bridge

The San Francisco Bay Toll-Bridge Company issued US$4,500,000 (equivalent to $62,000,000 in 2016) in bonds to raise a portion of the estimated US$7,500,000 (equivalent to $103,400,000 in 2016) budget required to build the first bridge. First-year operating revenues were anticipated to be US$868,469 (equivalent to $11,974,000 in 2016), but the original bridge lost money in its first year of operation.

The original bridge, known as the San Francisco Bay toll bridge, opened on 2 March 1929 after approximately a year of construction. It was a privately owned venture and was then the longest bridge in the world. The original bridge was mostly a two-lane causeway trestle with five 300-foot (91 m) truss spans in the center incorporating a vertical lift over the main shipping channel. Clearance when the lift was down to allow road traffic over the bridge was 35 feet (11 m), and clearance with the lift up to allow marine traffic to pass the bridge was 135 feet (41 m).

The original drawbridge played a minor role in the history of the Stanford Axe. When Stanford students stole the Axe back from Cal in April 1930, the getaway car was presumed to be traveling the shortest route, which would be over the bridge, and pursuing Cal students gave chase. The operator on duty, who was a graduate student at Stanford, learned that Cal students were causing the increased traffic in pursuit of the Axe, so he raised the draw and stopped traffic. In fact, the getaway car was traveling back to Palo Alto via San Jose.

Although the initial press was favorable, daily traffic fell from the opening months and never exceeded 2,000 cars per day until 1947. The State of California purchased the bridge on 12 September 1951 for US$6,000,000 (equivalent to $55,400,000 in 2016). By 1955, traffic exceeded 9,000 cars per day,] and in 1957, traffic was stopped an average of six times per day to allow ship traffic to pass the bridge. The bridge originally had pole lights along the entire stretch, which were later abandoned except over the vertical lift span. Traffic on the bridge increased from 3,000 cars per day in 1929 to 56,000 cars per day in 1968. Before the new bridge was complete, California put the original truss spans up for sale in 1965, with the buyer obligated to remove all five truss spans after completion of the 1967 bridge.

1967 Orthotropic Bridge

With increased road and marine traffic, a bill was introduced in 1961 by State Senator Richard J. Dolwig to fund a new fixed high-level bridge to replace the 1929 lift-bridge. The modern span, which began construction on 17 July 1961, opened for traffic in 1967 at a cost of US$70,000,000 (equivalent to $503,000,000 in 2016). The originally designed upgrade would retain the existing lift span (along with the attendant delays due to passing ship traffic), adding a second deck to the truss spans and widening the existing trestles to four lanes, but the California Toll Bridge Authority added US$30,000,000 (equivalent to $240,400,000 in 2016) to the project budget in September 1961 to replace the existing lift span with a fixed high-level double-deck span, which would have been similar in appearance to the nearby 1956 Richmond–San Rafael Bridge.

By that time, prior phases of the project had already been awarded to relocate the toll plaza from San Mateo to Hayward on new fill and bids were taken for the new eastern trestle, with trestle construction awarded to Peter Kiewit Sons’. The finished single-deck design was not finalized until January 1962, with work initially estimated to complete in 1965.

The new span won two prizes in 1968: an ASCE Award for Outstanding Civil Engineering Achievement and an American Institute of Steel Construction long-span prize bridge award.

William Stephen Allen was retained as an architectural consultant, although the bridge was designed by the Bay Toll Crossings Division (under Chief Engineer Norman C. Raab) of the California Department of Public Works. Chuck Seim, one of the design engineers working for Bay Toll Crossings, would later credit Allan Temko’s criticism of Raab’s economical truss design for the Richmond–San Rafael crossing for generating sufficient public pressure to drive the single-deck design. Temko’s article quoted Tung-Yen Lin as being against a repeat of the Richmond–San Rafael design, but Lin ultimately gave Temko the credit for the design. Raab retired and his successor, E.R. “Mike” Foley, was willing to incorporate aesthetic considerations, resulting in the final design. The western highrise span features an all-steel superstructure, with an orthotropic deck over two parallel box girders, following the construction of several smaller test bridges using the same orthotropic deck technology. It was the first large-scale use of an orthotropic deck, which reduces weight, and thus seismic loading, although the bridge is expected to receive moderate to major damage following an earthquake.

Murphy Pacific Marine built the Marine Boss floating barge-crane in 1966 with a 500-short-ton (454 t) capacity to perform the heavy box girder and deck-section lifts. The heavy lift capacity of Marine Boss enabled Murphy Pacific to raise much longer prefabricated girders than existing barge cranes would have allowed. Box girder and deck sections were fabricated in Murphy Pacific’s Richmond yard and were carried by Marine Boss to the bridge construction site. Marine Boss was sold for scrap in 1988 to Weeks Marine in New Jersey, who renamed it the Weeks 533 and refurbished it. Weeks 533 has since been used for several notable heavy lifts, including moving the Concorde and Enterprise onto the Intrepid Sea, Air & Space Museum and lifting the downed hull of US Airways Flight 1549 from the Hudson River.

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The highrise section of the San Mateo-Hayward bridge (1967 span).

The total length of the bridge is 7 miles (11.3 km), which is made up of a western 1.9-mile (3.1 km) highrise section and an eastern 5.1 miles (8.2 km) trestle section. 425,000 cubic yards (324,936 m3) of fill were used at the Hayward end to reclaim land for placing the toll plaza and administrative buildings. The eastern trestle span was built on 4,840 prestressed hollow concrete piles, each 60–90 feet (18–27 m) long. The contractor built a casting yard in Richmond to produce the concrete piles continuously. The new eastern trestle span was completed in 1963 and traffic over the existing 1929 bridge was moved over to it.

Work on the western highrise span was bid in October 1964 and commenced in 1965. It crosses a shipping channel, with an orthotropic main span that is 750 feet (229 m) long (at the time, the longest girder span in the United States) and has a vertical clearance of 135 feet (41 m). The main span is flanked by two orthotropic back spans which are each 375 feet (114 m) long, and there are seven orthotropic side spans on the approach to each back span. Each of these side spans are 292 feet (89 m) long. Although these spans appear to be formed from continuous box girders, they consist of alternating anchor spans and suspended spans. Anchor spans rest on top of two adjacent piers and cantilever over each side slightly, and suspended spans are hung between the ends of two adjacent anchor spans. There are an additional nine 208-foot (63 m) steel spans carrying a concrete deck on the San Mateo side of the highrise, and ten steel spans carrying a concrete deck on the Hayward side, ranging from 186–208 feet (57–63 m). The bridge carries about 93,000 cars and other vehicles on a typical day, almost double its original projected design capacity of 50,000 vehicles per day.

The steel deck of the bridge, approximately 418,000 square feet (38,833 m2), was paved with an epoxy asphalt concrete wearing surface in two layers. The San Mateo Bridge was the first deployment of an epoxy asphalt concrete wearing surface. As of 2005, the original wearing surface was still in use, but was subsequently replaced in 2015.

The highrise section was initially built with six lanes and the eastern causeway with four lanes (two in each direction). The causeway section was a perennial traffic bottleneck until it was expanded to six lanes in 2002, along with much needed improvements in its connections with Interstate 880 in Hayward.

Bus service over the bridge is provided by AC Transit’s Line M Transbay service.

San Mateo-Hayward Bridge

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San Mateo-Hayward Bridge (1967), showing some of the electric transmission towers paralleling the bridge route and Werder Pier (at left)

High-voltage power lines built by PG&E in the 1950s parallel the bridge all the way across the bay. They provide power to the peninsula and San Francisco.

Upgrades and repairs

Seismic upgrades (1997–2000)

The bridge was closed in the wake of the 1989 Loma Prieta earthquake as a precaution, but reopened on 18 October 1989. It underwent an extensive seismic retrofitting from 1997 through 2000 to protect against earthquake damage.

Widening (2002–2003)

The bridge was considered the worst evening commute in the Bay Area, which ended with the completion of a new eastern trestle carrying westbound bridge traffic in 2002. Eastbound bridge traffic took over the old trestle completely, although eastbound traffic was not expanded to three lanes until February 2003. Funded as part of BATA’s regional Measure (RM) 1 program, which raised bridge tolls, the new low-rise trestle portion of the bridge added 10 feet (3.0 m) shoulders on both sides in both directions and effectively widened traffic from four to six lanes, matching the configuration of the high-rise portion of the bridge. With the completion of the new westbound trestle, the speed limit on the bridge was raised to 65 miles per hour (105 km/h).

Seismic beam (2010–2012)

A beam, which had been added as part of the seismic retrofit project, was found in a cracked condition during a routine inspection in October 2010. The beam, which was on the westbound approach to (east of) the highrise section, was patched with a steel plate as an emergency repair, and permanent repairs, requiring a weekend shutdown, were completed two years later.

Repaving (2015)

After nearly forty years of service from the original orthotropic deck wearing surface, Myers and Sons Construction, a partnership between C. C. Myers and Sterling Construction Company, was the selected bidder to remove and replace the wearing surface on the highrise portion in 2015. The work required two full weekend closures on 8–11 May 2015 and 22–25 May 2015. The new polyester concrete wearing surface, developed by Caltrans and used to great success in other Bay Area bridges, is anticipated to be at least as durable as the original epoxy asphalt concrete, according to laboratory tests conducted at the University of Missouri-Columbia.

The bridge was closed to traffic, for the first time since opening, starting at 10pm on Friday, May 8, 2015, for resurfacing and maintenance. The bridge reopened before 4am on Monday, May 11, 2015. It closed again for the final phase over Memorial Day weekend, May 22–25, 2015, fully reopening by 4:55am on May 25.

Werder Pier

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Werder Pier, the remnant of the original 1929 western trestle span

After the new bridge was built, the old bridge was demolished but the western approach (the trestle span up to the original truss spans) was purchased by the County of San Mateo in 1968 for the nominal sum of US$10 (equivalent to $70 in 2016) and retained as the 4,055 feet (1,236 m) Werder Fishing Pier, which was known as one of the best places to catch sharks in San Francisco Bay. San Mateo County operated Werder Pier under a lease agreement with Caltrans, which stated that Caltrans may temporarily revoke the lease in order to perform use the pier as a staging area for repairs to the 1967 span, and that San Mateo County must maintain the pier and keep it open for public use for twenty-five years.

Werder Pier was closed to the public in 1996, when Caltrans used it as an equipment staging area for the seismic retrofit of the 1967 span. In addition, there were liability concerns since the pier’s structure had degraded due to exposure to marine elements. A report was prepared for the County in 2004; the cost of rehabilitating the pier and providing some improvements was estimated at up to US$7,200,000 (equivalent to $9,100,000 in 2016), depending on a more detailed evaluation of the pier’s condition, since the investigation for the report revealed numerous cracks, spalls and exposed reinforcing steel. However, the report also stated the pier did not require any seismic retrofitting.

As of 2013 ownership of the parking lot and land access to the pier was transferred to Foster City. Initial concepts for the newly acquired space included a possible ice rink and ferry terminal, but the land was deemed too environmentally sensitive to support high-intensity use. The park carried an interim name of Werder Park, and was dedicated as Bridgeview Park for a grand opening on June 27, 2015.

Tolls


Tolls are only collected from westbound traffic at the toll plaza on the east side of the bridge. Since July 2010, the toll rate for passenger cars is $5. For vehicles with more than two axles, the toll rate is $5 per axle. Drivers may either pay by cash or use the FasTrak electronic toll collection device. During peak traffic hours, the two left lanes are designated HOV lanes, allowing carpool vehicles carrying two or more people or motorcycles to pass for a toll of $2.50. The next three lanes are FasTrak-only lanes. During non-peak hours the two HOV lanes become FasTrak-only lanes.

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