A search for a missing Caspar Creek Bridge road sign found it deeply entangled in vines beneath massive but mostly unseen pillars.
This was just one indication that the 14 aging bridges along the Mendocino Coast”s Highway 1 examined in this series have gone from admired to mostly forgotten.
Even though the structures are largely ignored, thousands of people every day put their lives onto the beams of tall bridges that are nearing the end of their anticipated lives. For 10,000 motorists a day, a trip across Caspar Creek takes about 5 seconds, and there isn”t much reason to look east or west at treetops, much less down at the bridge. The search for just the right angle to photograph Caspar Creek Bridge showed how little current interest there is in the structure.
The best path to see the bridge, on the southwest, was littered with the remains of about a dozen butchered deer, rotting atop garbage, apparently dumped by some poacher where nobody would look.
There was no evidence that anybody had been under the massive bridge recently, not even the usual trash and graffiti.
Yet back in 1966, the Caspar Creek Bridge was a true California celebrity.
At the north end, there is an almost completely faded wooden sign saying that “Mrs. Edmund Brown” presided over a gala dedication ceremony on Oct., 3, 1966.
“She broke a champagne bottle on the bridge abutment, and it was a big party,” said Michael Potts, who has an Mendocino Community Network historical Website about Caspar.
Bernice Layne Brown came to Caspar to christen the final jewel in the greatest building wave ever on the California Coast—the Coast Highway.
“It”s an amazing structure,” said Potts. “The new concrete Caspar Creek Bridge was the centerpiece of the whole Coast Highway in our county,” said Potts.
“Before that Point Cabrillo Drive was Highway 1, if you can picture that. I remember logging trucks making that hairpin turn, which was frightening,” said Potts.
1966 was the end of a era when the first name of the colorful daughter of a famed Los Angeles Police Department lieutenant and political partner and wife of Gov. Pat Brown was omitted in favor of her husband”s first name.
But it was also the end of a building era, unprecedented in world history, when America built suburbs, dams and highways, with few worries. The Vietnam War protests, the environmental movement and serious worries about the pace of dam and bridge building after the war were about to flower.
The state had an improbable task in creating Coastal Highway 1, bridging dozens of gaping canyons both south and north of San Francisco during 33 years full of Depression, World War and lots of post-war Manifest Destiny.
That 20th century history of the Mendocino Coast is visible in the beams and designs of the 14 Shoreline Highway bridges beginning at the Greenwood Creek Bridge and ending at Ten Mile Bridge.
The legacy of the past is inspiring — the safety travelers enjoy was built in by the high standards and values of a previous generation. But it also isn”t so pretty for the future as all but one of the bridges are nearing the end of their anticipated lives. National Bridge Inventory data also raises some red flags about several of the towering old structures.
In 1967, the greatest bridge disaster in modern U.S. history happened, when the Silver Bridge fell into the Ohio River, killing 46 people. That disaster (featured in the movie “The Mothman Prophesies”) resulted in the creation of federal bridge inspection standards and eventually National Bridge Inventory ratings of bridges needing work to remain safe as “structurally deficient.”
A deficient bridge, when left open to traffic, typically requires significant maintenance and repair to remain in service, according to the Federal Highway Administration. A structurally deficient bridge with a sufficiency rating below 50 (out of 100 points) qualifies for federal funds to replace it. Between 50 and 80, a deficient bridge is eligible for federal funds to repair it, American Society of Civil Engineers board member Andrew Herrmann told the Advocate-News and The Mendocino Beacon.
The American Society of Civil Engineers gave the nation”s bridges a “C” and estimates more than $10 billion per year will need to be spent to repair and replace structurally deficient bridges before they become unsafe.
Six of the 13 Mendocino Coast Highway Bridges between Elk and Ten Mile River earn the worrisome “structurally deficient” designation. They are the Greenwood Creek, Salmon Creek, Big River, Jughandle Creek, Hare Creek and Ten Mile River bridges.
An in-depth look at bridge history and inspection data shows that the most problematic building locally was done just after World War II, when bridge building became less about quality and more about working fast and saving money.
With salt-air hitting all 14 of the bridges on a daily basis, Caltrans faces unique challenges on the Mendocino Coast.
“Some bridges along the coast do present special challenges due to their exposure to the salt environment,” said Caltrans engineer Barton Newton.
“In some cases, portions of a bridge have more extreme exposure than other portions of the same bridge,” said Newton. “In particular, steel bridges along the coast have a shorter paint system life when compared to bridges elsewhere. The environment that these bridges are painted in also presents additional challenges that are not encountered elsewhere. All exposed metal parts of bridges along the coast are subject to more rapid deterioration, resulting in higher costs and more frequent repairs.”
Greenwood Creek
Over the past decade, taxpayers have spent nearly $100 million locally to fix or replace three local postwar bridges. Tens of millions more will be spent on the next postwar bridge to be replaced, the 505-foot-long Greenwood Creek Bridge in Elk, built in 1956. Its deck is in “imminent failure” condition, the worst possible rating, which demands replacement.
Instead of a fix, Caltrans will replace the entire bridge in 2009. The Greenwood Creek Bridge also has unstable foundations that could make the bridge fail in the case of a likely flood, National Bridge Inventory data shows.
“The bridge is scour critical and the foundations are unstable for the scour conditions. [Scour is washout during high water.] The existing deck has a history of yielding and raveling asphalt. There are multiple medium shear cracks in the exterior girders near both abutments. The asphalt deck surface is generally in rough condition, with numerous existing patches ?” says a report from Caltrans. “Unless corrective action is taken, the bridge will require an increasing maintenance effort and will eventually fail.”
The report lists many more problems with this bridge. Despite this, the bridge earns a sufficiency rating of 73.9 out of 100, meaning the superstructure and substructure had top scores and illustrating how NBI data can be misleading if taken only in part.
Caspar Creek
The 860-foot-long Caspar Creek Bridge is one bridge with no red flags in its inspection data. Its sufficiency rating on a scale of 1 to 100 is 67.
The superstructure, which rates as fair, is composed of seven massive pillars made of pre-stressed reinforced concrete. Its deck is rated as satisfactory, and its substructure”s condition is good.
Unlike the bridge in Elk, the creek below isn”t seen as a potential threat to the Caspar Creek Bridge (nor any of the other 13), each passing the crucial scour test for foreseeable flood events.
Prior to 1933, Highway 1 was a meandering gravel road that delved into each river canyon along the California Coast, crossing frightening low bridges that often got washed out in winter. There were tolls on virtually all the bridges.
The Caspar Lumber Company built the old Caspar Creek Bridge and allowed free travel on it, according to Ted Wurm”s book on the history of the Caspar Lumber Company.
The old county bridges were often of poor quality. A Savings Bank of Mendocino County calendar shows a truck that had just fallen through the low wooden bridge that connected North Harbor Drive and South Harbor Drive. Although everyone knew that high bridges would make travel much safer and faster, they were too expensive and difficult for local agencies or timber companies to build.
The agency later known as Caltrans took over the task of building these difficult bridges in 1933, with a dual mission of architectural beauty and engineering quality and functionality.
“The Bridge Department group, led by Harlan D. Miller had high ideals relating to the aesthetics and architecture of bridge design,” a Caltrans report states. “They were responsible for the design of many of the state”s open-spandrel arch bridges, most notably the series of early 1930s structures along State Route 1,” the study states.
Roosevelt teams with Caltrans in New Deal
Caltrans took over from the counties at the same time as federal New Deal funding arrived.
Robert Winn”s Mendocino Historical Research, Inc. publication, “Bridges, Huckleberries and Robin Stew,” chronicles how the Franklin D. Roosevelt Administration came to the rescue of the Mendocino Coast (and countless other rural areas) during the Great Depression with the Works Progress Administration and other efforts.
The WPA employed thousands of local people. Millions were spent in the coast economy to build Cotton Auditorium, the Mendocino Woodlands Camp and to bridge three difficult chasms.
These were built to be spectacular and lasting monuments by what some saw as a socialist federal government. There was no effort to cut corners with cheaper design, New Deal histories shows.
1938 saw the building of the concrete arch bridge at Jughandle Creek, followed by the concrete girder bridge at Jack Peters Creek in 1939 and then the spectacular Russian Gulch Bridge.
“The Russian Gulch Bridge is the jewel of the Shoreline Highway,” Wurm”s book says, quoting sources of that time. “It”s design, the open spandrel concrete arch,” combines strength and beauty, making visible the powerful forces it holds in repose.”
The Jughandle Creek and Russian Gulch bridges each feature the curved Roman arch and ornamental concrete handrails. These were architectural statements and a tribute by Harlan Miller, Caltrans” most famous chief engineer, to the history of architecture.
The Pacific Coast Highway 1, from San Luis Obispo north is dotted with graceful structures he helped create in the 1930s.
Jughandle Creek
The 387-foot-long arched Jughandle Creek Bridge is now the worst of the three WPA “New Deal” Mendocino Coast bridges. Although it was reconstructed in 1966, Jughandle still rates only a 33 on a scale of 1 to 100, while the Minnesota Bridge that collapsed Aug. 1 rated a 50. Its “substructure” — the pilings and concrete abutments the towering arch sits on — get a “poor” rating, one of the few such low National Bridge Inventory ratings for bridges on the coast.
“The reconstruction” work that was completed in the 1960s was a widening of the bridge deck and did not include foundation work,” said Caltrans” Newton.
“The substructure rating of poor” is based on the spalls [chips or small holes] and delaminations [soft spots] on the columns and bent caps [horizontal beams on top of columns], which are considered substructure elements of this bridge,” Newton said.
While that might not sound comforting to the traveler over Jughandle Creek Bridge, the bridge qualifies for federal replacement funds based on its low rating. It also gets inspected more often than bridges without such red flags, which are inspected by Caltrans at least once every two years.
Bridge condition is rated on a scale of 1 to 9. Failed condition being 1 and excellent condition being 9. Poor is 4, Serious is 3 and Critical is 2. A bridge in critical condition must either be scheduled to be closed or repairs made. Closure is mandatory when a bridge is listed as “failed.”
Jack Peters Creek
The best quality New Deal bridge is the least spectacular, the 223-foot-long Jack Peters Creek Bridge just north of Mendocino. It rates as “equal to present minimum criteria,” in the National Bridge Inventory, a higher structural evaluation rating than some newer bridges on the coast.
Its overall score of 73 also indicates good condition, especially for its age and daily exposure to salt air. The data shows no reason for concern about the 69-year-old concrete box-girder bridge. All of its components rank in “good” condition save the superstructure, which is in satisfactory condition.
Russian Gulch
The 525-foot-long Russian Gulch Bridge, gets mostly fair and good marks marks, a 58.4 sufficiency rating and a substructure that rates fair, with the rest of the components getting “satisfactory” ratings.
The bridge, which underwent seismic retrofit a decade ago, is featured in engineering and photo publications, including as a classic example of the arch in the Encyclopedia Americana.
Both Jack Peters Creek and Russian Gulch are listed as “functionally obsolete,” because the bridge decks are narrow for the amount of traffic that now crosses them, Newton said.
Part 3 of 3, which includes information on the remaining Mendocino Coast bridges, will be published in the Sept. 27 edition.
SIDEBAR #1
Fracture critical bridges
Provided below is a list of the nine fracture critical state highway system bridges in Mendocino County, as provided by Caltrans. There are 238 of the bridges in California, including major bridges like the Richmond-San Rafael Bridge.
Caltrans released a full list of the bridges following the Aug. 1 Minnesota bridge collapse, as it was also a fracture-critical bridge. A fracture critical bridge is a steel structure that is designed with little or no load path redundancy. That means the bridge is less likely to hold together if one major component fails.
This designation is a function of the design of the bridge and not the condition. In fact, a brand new bridge can be fracture critical.
Caltrans has a fracture critical inspection unit that uses specialized access and non-destructive testing equipment to identify any potential concerns, even those that are not visible to the human eye.
Mendocino Coast fracture-critical bridges
– Garcia River Bridge, carries Highway 1
– Navarro River Bridge, carries Highway 1
– Salmon Creek Bridge, carries Highway 1
– Albion River Bridge carries Highway 1
Other Mendocino County fracture-critical bridges
– South Fork Eel River Bridge, carries Highway 1 at milepost 104.96
– East Fork Russian River Bridge, carries Highway 20 at milepost 36.36
– South Fork Eel River bridge, carries Highway 271
– Jitney Gulch Bridge, carries Highway 101
– Russian River Bridge, carries Highway 101 at milepost 9.24
SIDEBAR #2
What they”re made of
Five Mendocino Coast bridge types
– Truss-deck: Albion River, Salmon Creek (and failed Minnesota and Ohio bridges)
– Box Beam or Girders: Multiple — Big River, Ten Mile River, new Noyo Bridge, Greenwood Creek, Jack Peters Creek
– Stringer/Multi-beam or Girder: Caspar Creek, Navarro, Howard Creek, Pudding Creek
– Arch ? Deck: Russian Gulch, Jughandle Creek, Hare Creek
– Tee Beam: James Creek on Highway 20, Orr Springs Road over Orr Creek
