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Rio Vista Bridge

The Rio Vista Bridge is a continuous truss span with a vertical-lift bridge in the middle which carries California State Route 12 across the Sacramento River at Rio Vista, California. The present bridge was completed in 1960 and is one of several moveable bridges spanning rivers in the Sacramento–San Joaquin River Delta. It is named after Helen Madere, who served as vice-mayor of Rio Vista. As of 2013 the bridge carries approximately 21,000 cars per day.

1919 bascule bridge
The original bridge spanning the Sacramento River was built in 1918 and opened in January 1919 at a cost of . From west to east, the 1919 bridge consisted of a concrete tied arch, the Strauss double-leaf bascule, three concrete tied arches and timber A-frame trestle spans. ==1960 tower bridge==
1960 tower bridge
The 1919 bridge was replaced during seventeen years of piecewise construction. The finished 1943–1960 bridge consists of thirteen steel Warren truss spans (with one of those being the vertical-lift chorded Warren truss main span) carried on twelve piers. The main lift span weighs , with an equal amount in counterweights, so the lift mechanism operates using two electric motors, one in each tower. In the event of electrical failure, backup electrical power is provided by a diesel generator set. Clearance under the raised lift is to the highest anticipated water level, and the navigation channel is wide between the timber fenders protecting the tower piers. With the lift down, vertical clearance is only . No one was injured in the crash, although two youths who were stopped on the bridge while the freighter passed were tossed into the river and were subsequently rescued. Once Ilice was freed from the wreckage, she proceeded upriver to Sacramento to take on its scheduled load of rice. The remnants of the destroyed span were cut free from the bridge and dropped into the water. A temporary repair consisting of a steel trestle and two steel girders was erected after three weeks, with a ferry carrying traffic across the river while the temporary span was erected. The Marine Boss crane barge, built for the heavy girder lifts during the construction of the 1967 San Mateo Bridge, erected a permanent replacement span (which included a cantilevered section to replace damage in the adjacent truss span) in June 1967 and removed both the wreckage from the original bridge and the temporary span at the same time. Renamed for Helen Madere In 1998, the Rio Vista Bridge was officially designated the Helen Madere Memorial Bridge after Helen Madere, a former vice-mayor of Rio Vista who served as that city's representative to the Solano Transportation Authority. The legislative act also cited her instrumental role in improving driver safety on California State Route 12. On August 9, 2018, the bridge again became stuck open for ten hours, until work crews were able to manually lower the draw. It was unable to be raised again until August 16, blocking marine shipments of rice and cement to the Port of West Sacramento. Caltrans made plans to manually raise and test the draw section after determining the motor gear box had failed, but warned motorists that repairs would take up to thirty days to complete, as the gearbox would need to be rebuilt in Alabama. The bridge was raised by hand, closing to road traffic overnight every few days to allow marine traffic to pass. Repairs to the bridge were completed on September 14. ==Proposed replacement==
Proposed replacement
The bridge opened 200 times for ship traffic during peak months in 2004 (nearly seven times per day); peak queues reached 200 vehicles extending and caused travel delays of up to 30 minutes. Fixed high-level bridges of various designs would require longer approaches to accommodate the required height with reasonable road grades, and resulted in the proposed alternative crossings north and south of the existing SR-12 alignment. Both a mid-level moveable bridge (with approximately of clearance with the draw down) and tunnel crossings were proposed for the existing alignment, with the mid-level bridge being named the preferred alternative in 1992. Rio Vista businesses along the existing SR-12 alignment urged no change to the route, worried that moving SR-12 traffic could result in business closures. One of the proposed measures to raise funds would have imposed a toll on the existing bridge, and was met with similar resistance. Caltrans performed a 2012 study for the entire SR-12 corridor, which concluded the cost of a replacement high-level bridge would be close to . The City of Rio Vista dropped its support for the north (Airport Road) alternative alignment in 2012. Preservation project Caltrans is undertaking a two-part preservation project for the bridge. The first part of this work, which involves cleaning and painting the bridge, is expected to complete in winter 2020 at a cost of $37.1 million. After the bridge has been repainted, the mechanical and electrical systems will be upgraded, starting in spring 2022, at an anticipated cost to range between $11.9 and $19.2 million. ==References==
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