US 6 – Santa Clara River Bridge – A Closer Look

US Highway 6, now known as Sierra Highway, crossed the Santa Clara River near Solemint, California. The bridge it originally used, constructed in 1938, is planned to be replaced in the near future. This bridge is one of the oldest remaining in the Santa Clarita area and is the longest span on former US 6 in California. The bridge has remained almost intact from its original construction. The only changes have been minor to the bridge itself. The highway, however, has changed quite a bit. In 1968, Sierra Highway, then State Route 14, was widened to four lanes. A second bridge for northbound traffic was added, with the original bridge being used for southbound traffic.

Presently, Sierra Highway is six lanes wide at the river crossing. As the bridges were built with a four-lane highway in mind, only a narrow shoulder along both directions exists. This condition is one of the reasons the bridges across the Santa Clara River are being replaced.

In March of 2017, I took a trip to inspect in more detail the bridge and the surrounding area. It was nice to see the bridge again, as it brought back a lot of memories. I used to live near the bridge and crossed it almost daily. It will be sad to see it go as it is one of the last remaining pieces of the old highway. So, please, check it out yourself while you still can. I’m not quite sure when the construction will begin, it may have already.

Main Structure:

Side view, from the northern end. Note the small arches along each span.
Southern abutment and wing wall.
Between the 1938 and 1968 spans. Quite a difference between the girders.
Deck view, looking northerly from the south end.
Side view showing the railing, arched spans, and wing wall.

Detailing:

Underside view of the bridge.
Closeup of the west side railing from the south end of the bridge.
View showing the railing at the expansion joint.
Expansion joint that may have moved during an earthquake or from settling.
Expansion joint along the bridge deck.
Deck drain detail.
Remaining section of railroad rail and wire fence embankment protection.

Sand Fire Information

As the Sand Fire has grown quite substantially in the past few days, it has become more difficult to track where it is going. I’ve found a couple of good links for up-to-date information on this fire. Map below courtesy of the Los Angeles County Fire Department.

Old US 99 at Weldon Summit

US 99, known as “The Old Road” in the Santa Clarita area, has had a varied past. It was first built through this area in 1930 as a three-lane highway. This roadway, known then as the Newhall Alternate, would be the first of many versions of the road through this pass.

This is the last remaining uncovered stretch of the 1930 Newhall Alternate concrete. Motorcycle is on the 1951 alignment.
This is the last remaining uncovered stretch of the 1930 Newhall Alternate concrete. Motorcycle is on the 1951 alignment.

In 1949, the roadway was temporarily widened to four lanes by restriping and adding some paving to the shoulder. This was done as the real work to upgrade the highway wouldn’t commence for a couple of years. Evidence of this widening can still be seen today.

Double white striping from a "temporary" four-lane configuration of the old three-lane concrete. This was done in 1949 as an interim measure before the road was reconstructed as an expressway in 1951.
Double white striping from a “temporary” four-lane configuration of the old three-lane concrete. This was done in 1949 as an interim measure before the road was reconstructed as an expressway in 1951.

In 1951, US 99 was realigned and finally upgraded to an expressway, though this would not last long. Just south of this point, the highway was realigned again to accomodate a new freeway from the Tunnel Station Junction (US 6 and Foothill Blvd) to Sepulveda Junction (State Route 7). This freeway still exists today in part and serves as the “Truck Route” through the pass.

North view of the old southbound lanes just south of the summit.
North view of the old southbound lanes just south of the summit.

Starting in 1967 and ending in 1975, the pass was yet again the site of major construction. This time, little of the old highway would be utilized as the new route of Interstate 5 bypassed much of the existing route. Where it didn’t bypass the alignment, it was torn up and completely replaced with the current roadway.

US 99 would, however, serve as the main route one last time following the January 17, 1994 Reseda / Northridge earthquake. Portions of I-5 collapsed during the earthquake, resulting in a need for a quick replacement. The resulting detours created an alignment very similar to the pre-1967 highway, giving motorists (albeit not with joy) a chance to drive old US 99 again. Upgrades were made to the highway through the pass including repaving, guardrail, and a temporary prohibition on left turns. Sadly, for highway historians, this resulted in the loss of the 1951 concrete and some curbing. It is a price to pay to help keep California’s Backbone functioning during a crisis.

Looking northerly toward Gavin Canyon. This was the location where I-5 was temporarily rerouted onto old US 99 in 1994.
Looking northerly toward Gavin Canyon. This was the location where I-5 was temporarily rerouted onto old US 99 in 1994.

Image of the Week – 3/9/15

St. Francis Dam site in 2006 from the reservoir side. The crumbling remains of the wing dam are visible on the ridge to the right.
St. Francis Dam site in 2006 from the reservoir side. The crumbling remains of the wing dam are visible on the ridge to the right.

March 12, 2015 will mark the 87th anniversary of the collapse of the St Francis Dam in San Francisquito Canyon, Los Angeles County, California. The collapse occurred just before midnight on March 12, 1928. It is still California’s second largest disaster in terms of lives lost. Approximately 500 people died in the ensuing flood which flowed to the ocean near Oxnard, CA along the Santa Clara River Valley. Only the 1906 San Francisco Earthquake and Fire exceeds the number.