The Lesser Spans: Richmond – San Rafael Bridge

October 5, 2015 | By | Reply More

1280px-Richmond-San_Rafeal_Bridge_wideSpanning various arms of the San Francisco Bay are several smaller bridges, such as the Southern Pacific railroad bridge between Martinez and Benicia, the drawbridge at Antioch over the San Joaquin channel, and the curving span over Richardson Bay, just north of Sausalito.

The second newest of the bay’s seven major crossings, opened in 1956, is the state-constructed Richmond-San Rafael Bridge across the north bay.

Replacing ferry line across the same route, the double-decked, four mile long structure can be ranked as one of the two longest high-level bridges in the world.

The Bay Bridge though slightly longer and much greater in total size, is actually two bridges connected by a tunnel.

1024px-Richmond_San_Rafael_Bridge_07802Architecturally the new bridge was less notable; its curious built-in sag in the middle between the two cantilever spans caused some bay area resident to dub it in the Rollercoaster Bridge.

Upon its opening, the Richmond–San Rafael bridge was the last bridge across San Francisco Bay to replace a previous ferry service, leaving the Benicia–Martinez Ferry across Carquinez Strait as the only remaining auto ferry in the Bay Area.

Until 1976, the Richmond-Rafael Bridge actually had three lanes – one lane was closed to install a temporary pipeline to alleviate a drought in Marin. After the pipeline was removed in 1978, the lane was restriped as a shoulder.

Nevertheless, the bridge really does represent a major engineering achievement because it crosses two heavily used shipping channels with water depths up to 65 ft, with difficult underwater soil conditions, and with swift tides and currents that comprise the full volume of water draining from the Central Valley into San Francisco Bay.

This four-mile long bridge is indeed a complex structure. It is made up of four distinct segments:

  • On the Marin side, two side-by-side 3,000-ft long concrete trestles, not far above the high tide water level, each carrying two lanes of traffic.
  • The curved western structural-steel approach where the two roadways become stacked vertically and rise to the height of the channel crossing.
  • The central segment of the bridge with stacked roadways and two, 1,070-ft long cantilever steel trusses spanning the two shipping channels with vertical clearances of 188 ft and 138 ft, and connected to each other by lower trusses with spans of 289 ft.
  • The eastern approach that drops both roadways to ground level and separates them so that they are once again side by side at the toll plaza on the Richmond end of the bridge.

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Category: Fog City - City of Fog, San Francisco Bay

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