Fernbridge is a
concrete
Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wid ...
arch bridge
An arch bridge is a bridge with abutments at each end shaped as a curved arch. Arch bridges work by transferring the weight of the bridge and its loads partially into a horizontal thrust restrained by the abutments at either side. A viaduct ...
designed by American engineer
John B. Leonard which opened in 1911 at the site of an earlier ferry crossing of the
Eel River. Fernbridge is the last crossing before the Eel arrives at the Pacific Ocean, and anchors one end of
California State Route 211
State Route 211 (SR 211) is a state highway in the U.S. state of California that connects Ferndale with U.S. 101 in Humboldt County. The highway was originally designed to be the northernmost segment of State Route 1, but after construction o ...
leading to
Ferndale, California
Ferndale is a city in Humboldt County, California, United States. Its population was 1,371 at the 2010 census, down from 1,382 at the 2000 census. The city contains dozens of well-preserved Victorian storefronts and homes. Ferndale is the nor ...
. When built, it was referred to as the "Queen of Bridges" and is still the longest functional poured concrete bridge in operation in the world.
Construction
After 17 years of petitioning by residents of Ferndale and the Eel River valley,
Humboldt County Supervisors accepted bids for construction in 1910, and work started March 20 of that year.
Reinforced concrete was used because studies after the
1906 San Francisco earthquake along of the
San Andreas Fault
The San Andreas Fault is a continental transform fault that extends roughly through California. It forms the tectonic boundary between the Pacific Plate and the North American Plate, and its motion is right-lateral strike-slip (horizonta ...
from Ferndale south to
San Jose, California
San Jose, officially San José (; ; ), is a major city in the U.S. state of California that is the cultural, financial, and political center of Silicon Valley and largest city in Northern California by both population and area. With a 2020 popu ...
showed that reinforced concrete withstood earthquakes. The nearly span cost to build, and consumed millions of board feet of local redwood timber for the framing. Construction was finished and the bridge put into operation on November 8, 1911.
As completed, the bridge had wooden trestle approach spans and long. The reinforced concrete structure was long overall with a wide roadway carried on seven long arches.
The original wooden approaches were replaced with the current concrete ramps in 1920.
Floods
The bridge survived floods in 1912, 1913, 1914, 1915, 1937, 1953,
1955,
1964
Events January
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and 1986.
In the 1955 Christmas Week flood, the flood waters measured deep at Fernbridge. The south side abutment was washed out, and the approach damaged.
During repairs the first end span was removed and an earthen embankment was built which shortened the bridge by about .
Nine years later during the Christmas flood of 1964, every
stream gauge on the Eel River was either inundated and useless or destroyed except the one at Fernbridge and nearly every bridge on the Eel River was badly damaged because the force of the water was aided by thousands of redwood logs stacked for winter mill production along the bank of the river as well as homes and barns swept away by the rapidly rising waters.
[ Bulletin No. 161, 43 pages plus appendices and charts] The flood peak at Fernbridge occurred at 4:00 a.m. on December 23 when the flood level was .
The waters stayed high for 24 hours, and the discharge was estimated to be in excess of .
A large island which had built itself upstream of the bridge was washed away in the wake of the 1964 floods.
Historic designation
On September 24, 1976, the
American Society of Civil Engineers
American(s) may refer to:
* American, something of, from, or related to the United States of America, commonly known as the "United States" or "America"
** Americans, citizens and nationals of the United States of America
** American ancestry, pe ...
designated Fernbridge as an historic
civil engineering
Civil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including public works such as roads, bridges, canals, dams, airports, sewa ...
landmark and installed a plaque on the northwest approach pylon to the bridge.
In 1987, the
California Department of Transportation
The California Department of Transportation (Caltrans) is an executive department of the U.S. state of California. The department is part of the cabinet-level California State Transportation Agency (CalSTA). Caltrans is headquartered in Sacr ...
(Caltrans) recommended studying the removal of Fernbridge and replacement with a more modern span, such as the many which have washed into the Eel River during floods which Fernbridge withstood.
The Eel River regularly floods Fernbridge to the tops of the lower ridge of the support. In some high flood years, photographs have been taken showing the water level over the upper cone-shaped tops of the support pillars
as well as valley-wide flooding in 1915. Residents of Ferndale campaigned to stop any changes to the historic bridge and Fernbridge was added to the
National Register of Historic Places
The National Register of Historic Places (NRHP) is the United States federal government's official list of districts, sites, buildings, structures and objects deemed worthy of preservation for their historical significance or "great artistic ...
on April 2, 1987.
Recent events
In 1995, Fernbridge served as the set for scenes in the movie ''
Outbreak
In epidemiology, an outbreak is a sudden increase in occurrences of a disease when cases are in excess of normal expectancy for the location or season. It may affect a small and localized group or impact upon thousands of people across an entire ...
'', where a string of U.S. Army tanks rolls across the bridge accompanied by low-flying assault helicopters. In 2008, Caltrans initiated restoration of the railings of Fernbridge to their original appearance. Additional small improvements were made in 2008 and 2009, but Fernbridge's general appearance remains unchanged.
For the 100th anniversary celebration on August 7, 2011, a ceremony was held, the bridge was officially closed to cross vehicular traffic,
a run over and back was held as was done on opening day in 1911, a parade of historic vehicles and local dignitaries crossed over, and a Ferndale resident borrowed construction lights and lit it at night.
The
Ferndale Museum produced a video related to the bridge and continues to exhibit information about its history.
The
United States Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...
maintains a live webcam at Fernbridge near their stream gauge to visually monitor stream conditions.
On December 20, 2022,
an earthquake damaged the bridge, and the California Highway Patrol temporarily closed it to all traffic. The bridge was fully repaired by March 2023 at a cost of over $12 million.
References
{{Humboldt County, California
Bridges in Humboldt County, California
Eel River (California)
Concrete bridges in California
Deck arch bridges in the United States
Bridges completed in 1911
Road bridges on the National Register of Historic Places in California
National Register of Historic Places in Humboldt County, California
1911 establishments in California