Painted Bridges - Los Angeles River Bridge

An under-appreciated class of painted bridges are structures covered with graffiti. In fact, bridge owners often pay to have graffiti removed! That's unfortunate since the best graffiti is a highly accomplished and beautiful folk art that enhances a bridge's appearance.

Few graffiti artists have the resources to cover an entire bridge with a single painting. Therefore, graffiti-embellished bridges have two appearances. From a distance we get a pointillistic impression of patterns and colors that remain indistinct while a closer look reveals individual works of art. For instance, looking at this railroad bridge across the Los Angeles River, we get an impression of a variety of colors representing a kind of collage on the steel through girder.

It's amazing how these artists manage to put their paintings on the outside of bridges. On this bridge they might have stood on the deck and painted their image while bending upside down over the girder. On taller structures they might have used rope climbing gear!

Please feel free to send your own favorite photos of graffiti-embellished bridges or your comments on the controversy of allowing graffiti to remain on bridges. Tomorrow, we'll take a closer look at individual works of bridge graffiti.

Painted Bridges - Los Angeles River Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Los Angeles River Bridges: The Glendale Hyperion Viaduct

The Glendale Hyperion Viaduct is a large interchange that carries traffic between Hollywood and Glendale across the Golden State Freeway and the Los Angeles River.  It is about five miles (8 km) north of Broadway Viaduct (the Buena Vista Bridge) which is the next historic arch bridge downstream.

The design of this interchange is credited to Merrill Butler who was the chief bridge engineer for the City of Los Angeles from the 1920's to the 1960's.  It is actually two arch bridges supported on the same long pier walls over the Los Angeles River.  The closer bridge (Glendale Boulevard Bridge) is 316 ft (96 m) long and 27.6 ft (8.4 m) wide. Note the architectural details such as the towers at the ends of the bridge and the pedestals supporting lamps over the piers.  The structure behind it is the Hyperion Avenue Bridge, which is 518.1 ft (158 m) long, 67.9 ft (21 m) wide, and has the same architectural details. Both bridges are reinforced concrete closed spandrel deck arches. 

The interchange includes six bridges as well as plaques and monuments to honor the soldiers who gave their lives during World War I (the interchange was opened a little after the first Memorial Day).

This is an almost a rural setting in the middle of Los Angeles.  The Los Angeles River is allowed to flow somewhat  freely (the channel doesn't have a concrete bottom, trees are growing in the river, and we can see the Verdugos Mountains in the distance) just south of Griffith Park and Los Feliz.

Los Angeles River Bridges: Glendale Hyperion Viaduct by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Los Angeles River Bridges: Atlantic Boulevard Bridge

The Atlantic Boulevard Bridge is a seven span, reinforced concrete deck arch that crosses the Los Angeles River about three miles south of the 26th Street Bridge.  This bridge is 464 ft (141.4 m) long with a maximum span length of 60 ft (18.3 m) and 72 ft wide (21.8 m) from edge of deck to edge of deck with six traffic lanes.  The bridge length is greater than 7 x 60 = 420 ft because the distance is from the beginning of bridge (BB) to end of bridge (EB) which is measured from behind the abutments.

The arches are supported by wide pier walls and by end diaphragm abutments. It was designed by the County of Los Angeles and completed in 1931.  Some of the architectural features of the bridge, like the original lamps that were mounted on pedestals above the piers and abutments have been removed.

Note how wide the Los Angeles River has become. The many railway tracks that followed the river north of downtown have now moved into a trench east of the river. The Alameda Corridor Project eliminated all at-grade railway crossings between the Ports of Long Beach and Los Angeles to downtown Los Angeles http://www.acta.org/. However, the transmission lines still follow the river.

This is the most southern of the architecturally unique arch bridges that cross the Los Angeles River. There are a dozen of these bridges, starting with the Glendale Hyperion Viaduct north of downtown Los Angeles, which we will look at tomorrow.

Los Angeles River Bridges: Atlantic Boulevard Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Los Angeles River Bridges: 26th Street Bridge

We are traveling south from Olympic Boulevard along the Los Angeles River to the City of Vernon.  Both Olympic Boulevard and 26th Street require three spans to cross the river, which continues to widen until we arrive at the estuary in Long Beach. The Los Angeles River's concrete channel gets bigger and bigger to carry all of the runoff that would otherwise flood the region during heavy rains. However, it remains too small to carry anything close to the 100 year flood, due to the reduction of vegetation and soil in the Los Angeles Basin to absorb the runoff.

The 26th Street Bridge was built in 1927 and had additional work done in 2000. It carries only two lanes of traffic and is composed of three 90 ft (27.4 km) reinforced concrete closed spandrel deck arches.  It is supported by squat, rectangular, single column bents and end diaphragm abutments.  It has some of the architectural features similar to the other arch bridges such as a knobby texture between the arches and the deck, floor beams that support the cantilevered deck, and nice details at the bents. The street lamps over the abutments and bents, if they once existed, are now gone.

This photo looks north at downtown Los Angeles.  We can see the Los Angeles City Hall and the Hollywood Hills in the background. A good reference is at http://bridgehunter.com/ca/los-angeles/53C0868/

Los Angeles River Bridges: 26th Street Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Los Angeles River Bridges: Olympic Boulevard Viaduct

I don't have a good photo of Olympic Boulevard Viaduct (a viaduct is a bridge composed of many spans). This viaduct is 1/4 mile south of the busy Santa Monica Freeway, 1/2 mile north of East 20th Street, and there are locked gates along the Los Angeles River so it was hard to get a good photo.

When I visited the viaduct in 2000, it was being taken apart for a seismic retrofit combined with some general maintenance.  The beautiful balusters in the photo are new and made using glass fiber reinforced concrete to match the original railing. The lampposts were removed for repair and temporarily replaced with strictly utilitarian lamps. The ornamental pylon supporting the lamp is obviously the original.  This bridge is in the same Beaux Arts style that was used on many of the arch bridges. The retrofit, like most arch bridge retrofits, involves tying the deck together at the expansion joints in order to carry the inertia force to the end piers. An additional requirement was that the retrofit had to be hidden from the public to preserve the aesthetics of the original structure. It was designed by Dokken Engineering and cost $9 million. More information is at LACity.

The Ninth Street Viaduct was built in 1925 but got its name changed (as well as the name of the boulevard) in honor of the 1932 Los Angeles Olympics.  Trolleys once ran up and down the boulevard and so a stronger girder and a thicker deck were provided along the middle of the viaduct.  The structure is 1,422 ft (433 m) long, with three open spandrel reinforced concrete deck arches over the Los Angeles River and with reinforced concrete T-girder spans that cross over many railway tracks on both sides of the river before descending to the ground. Very substantial piers that are well-anchored into the soil were required at the ends of the arch spans to resist the longitudinal arch force.  The designer of record was Los Angeles city engineer Merrill Butler whose staff must have designed every arch bridge in downtown Los Angeles.

Los Angeles River Bridges: Olympic Boulevard Viaduct by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Los Angeles River Bridges: Seventh Street Viaduct

The Seventh Street Viaduct is one block south of the Sixth Street Viaduct we looked at yesterday.  This structure, built in 1910,  began as a three-span arch bridge over the Los Angeles River.  However, a second deck was added  in 1927 to allow traffic to drive above the trains that ran along both sides of the river.  You can no longer drive on the first deck because it now supports the second deck with three- column bents between each pier.  

The Seventh Street Viaduct is 1000 feet (305 meters) long and 56 feet (17 meters) wide.  The three reinforced concrete deck arches over the Los Angeles River are 92 feet (28 meters) in length.  This viaduct is an interesting and attractive structure in spite or, perhaps due to,  the  addition of the second deck  which was  an afterthought rather than  part of the initial design.   It is unclear from the photograph whether the piers going up to the second deck were added in 1927 or were originally porticoes.   Note the nicely detailed lamp posts atop each pier on the top deck.  The industrial setting and spray painted art provide an evocative context.   It is difficult to imagine how the bridge looked in 1910 when it was originally constructed.  The Los Angeles River was not yet a concrete channel.  However,  it was used as an open quarry for aggregates used in the making of  concrete.  

Los Angeles River Bridges: Seventh Street Viaduct by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Los Angeles River Bridges: Sixth Street Viaduct

Unlike the other river crossings, the Sixth Street Viaduct includes a two-span, steel through arch over the Los Angeles River.  It was designed by Los Angeles city engineer Merrill Butler, but instead of the neo-classical look of his other bridges, this is more of a streamlined Art-Deco design.

Steel members hang from the arches and support the deck with steel floor beams.  Instead of circular arches, these arches are parabolic segments that descend well below the deck and are supported near the bottom of the center pier.  All the piers have clean lines, matching the Art Deco buildings that were being constructed when the bridge was built (in 1932).

The viaduct is 3546 ft (1080 m) long with 150 ft (46 m) long arches and it's 60 ft ( 17.9 m) wide with four traffic lanes. Unfortunately, the bridge was constructed using aggregates with reactive silica that weakened the concrete over time.  Also the bridge hasn't been well maintained and the arches and rebar are rusted.  In fact, no access was provided to get to many areas of the bridge.  Today, this historic bridge has to be replaced, and at considerable additional cost if the city tries to duplicate the original design.

Los Angeles River Bridges: Sixth Street Viaduct by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Los Angeles River Bridges: Fourth Street Viaduct

We've spent the last week looking at arch bridges across the Los Angeles River. Before that, we looked at arch bridges crossing London's River Thames. I wonder what similarities and differences we can identify between arch bridges in these two cities?

Both cities sought to make a more pleasant environment by creating beautiful bridges.  In London, They built highly ornate steel (or iron) deck arches. In Los Angeles, its highly ornate, reinforced concrete deck arches. In downtown London, it required five spans to get across the river. In downtown Los Angeles only one or two spans are needed.  

Los Angeles is in the desert and the river is dry except during the winter.  Therefore, the expense of building cofferdams for bridge foundations is avoided.  However, both rivers have the potential for flooding and the bridges are built with cutwaters to keep debris from damaging piers.

The Los Angeles River often divides rich and poor communities, especially in downtown Los Angeles.   I didn't get a sense of that when I was walking along the Thames. 

The Fourth Street Viaduct was designed by city engineer Merrill Butler and opened in 1930. It is 1837 ft (560 m) long with 25 spans, 70 ft (21 m) wide with five lanes, and it has a single 279 ft (85 m) open spandrel, arch span over the Los Angeles River.

The bridge was designed in the Beaux Arts style introduced during the 1893 Chicago World's Fair, a style that was enthusiastically adopted by the City of Los Angeles. These bridge are along the railway tracks to Union Station and gave visitors the impression that Los Angeles was an affluent and dignified city. Note the familiar use of porticoes at the ends of the arch and the ornate lamps and balusters. Like the other arch river crossings, this bridge was seismically retrofitted in 1995 without impacting its appearance.

Los Angeles River Bridges: Fourth Street Viaduct by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Los Angeles River Bridges: First Street Viaduct

Unlike the Cesar E. Chavez Avenue Viaduct, the First Street Viaduct crosses the Los Angeles River in two shorter (148 ft) arch spans.  Also, the neo-classical porticos are not as embellished as on the Cesar E. Chavez Avenue Viaduct.

The First Street Viaduct was designed by Los Angeles city engineer Merrill Butler and opened in 1929. It is a twenty eight span viaduct that is 1327 ft long and is 71 ft wide with four traffic lanes.

The bridge is currently being widened 26 ft (8 m) to accommodate the Gold Line Metro that will run down the middle of First Street.

Los Angeles River Bridges: First Street Viaduct by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Los Angeles River Bridges: Cesar E. Chavez Avenue Viaduct

In the 1920's, there was a steel truss bridge that carried Macy Street over the Los Angeles River. However the bridge was old, vulnerable to damage when the river flooded, and required traffic to stop for trains on both sides of the bridge.

The City of Los Angeles decided to replace this bridge, along with several other river crossings in the downtown area, with viaducts that included beautiful, reinforced concrete deck arches over the Los Angeles River.

Macy Street was particularly significant to California residents as it was part of El Camino Real, the road that carried travelers from San Diego to Sonoma (about 600 miles) when California was part of Spain. That may explain why the new bridge (completed in 1926) was designed in the Spanish Baroque style, with handsome porticos consisting of spiral columns and decorated capitals supporting a cornice carrying seashells and the seal of Los Angeles. These architectural features were preserved when the bridge was retrofitted in 1995 to protect it from earthquakes.

The viaduct is 1270 (390 m) long, 71 ft (22 m) wide, and spans the river in a single 215 ft (65 m) arch. Merrill Butler, the city engineer was responsible for the design and the Atkinson-Spicer Company won the contract to build the bridge with a bid of $325,000.

The name of the bridge was changed from Macy Street Viaduct (after an area businessman and politician) to the Cesar E. Chavez Avenue Viaduct in 1995 to honor the civil rights activist.

Los Angeles River Bridges: Cesar E. Chavez Avenue Viaduct by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Los Angeles River Bridges: North Main Street Bridge

The Los Angeles River currently flows east for about 40 miles along the north side of the Santa Monica Mountains and then turns south for another 40 miles until it empties into San Pedro Bay. As the river approaches downtown Los Angeles it's crossed by ten old arch bridges.

I was hoping that since today is Cesar Chavez's birthday, I would be able to discuss the bridge that bears his name. However, the next bridge downstream is North Main Street, a reinforced concrete deck arch built in 1910 by Carl Leonhardt and H.G. Parker. It is a three span, open spandrel arch, 300 ft (91 m) long and 56 ft (17 m) wide. It's in an industrial area with railway tracks and transmission towers on both sides of the river. The bridge has two pier walls in the river with large cutwaters to protect it during floods. It would be interesting (but maybe dangerous) to see this river running full. The bridge has been here for 100 years, so apparently the cutwaters are doing a good job.

Los Angeles River Bridges: North Main Street Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Los Angeles River Bridges: North Spring Street Bridge

After spending two weeks looking at arch bridges across the Thames, we are moving to Los Angeles to look at their river crossings. Although the Los Angeles River is often dry and has a concrete liner for much of its length, it is a tidal river just like the Thames, at least near its mouth in Long Beach. Like the Thames, the Los Angeles River poses a flood hazard to its residents because it cannot carry all the water from the river basin during long heavy rains. Although Los Angeles is far younger than London, it has some well-designed, older arch bridges in the downtown area.

We looked at the Broadway Bridge (just north of this bridge) on February 19th. It's the most northern of the arch river crossings (except for the Hyperion Bridge in Glendale) and was built in 1910.

In 1874 the Downey Avenue Bridge (named after the governor) was built at this site. It was replaced in 1928 by the current North Spring Street Bridge. It is a long viaduct crossing over railroad tracks and city streets and includes a two-span, open spandrel, deck-arch across the Los Angeles River. It was strengthened in 1939, got a seismic retrofit in 1992, and was undamaged during the 1994 Northridge earthquake.

The bridge is 682 ft (208 m) long, 40 ft (12 m) wide, and each arch span is 146 ft (45 m) long.

The North Spring Street Bridge isn't as handsome as North Broadway. The approaches are girder spans instead of arches like on North Broadway. The arch ribs are separate instead of continuous and there aren't any architectural details.

Note the huge cutwaters they put on both sides of the pier to protect it from debris that can be carried during floods. These walls provide a convenient location to paint graffiti as shown in the photo (you can see the North Broadway Bridge behind North Spring Street in the photo).

More information on the Los Angeles River can be found at http://folar.org/

More information about the North Spring Street Bridge is at http://bridgehunter.com/ca/los-angeles/53C0859/

Los Angeles River Bridges: North Spring Street Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Arch Bridges: Buena Vista (Broadway) Bridge

Since we studied a closed spandrel arch bridge yesterday I thought we might look at an open spandrel arch today.

Downtown Los Angeles was more rural in appearance when the Buena Vista Bridge (across the Los Angeles River) was built in 1910.  Certainly, this bridge was grander before its sculptural details were removed. Actually, this photo was taken while the bridge was being retrofit, which required taking most of it apart and reassembling it. Seismic retrofits for deck arch bridges require strengthening the spandrel columns and tying the deck together to carry the longitudinal forces to the abutments. There are a couple dozen reinforced concrete arch bridges in Los Angeles and Pasadena that were retrofitted in the 1990's, usually at more expense than replacing the bridges would have cost.

This structure, designed by the architect A.F. Rosenheim, is typical of open spandrel, reinforced concrete bridges built in California at the beginning of the 20th century.  Steel was expensive (and considered ugly) in California, concrete was cheap, and the ornate Beaux Arts style was applied to bridges with the idea of making new cities (like Los Angeles) more attractive. 

Arch Bridges: Buena Vista (Broadway) Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution 3.0 United States License.

Los Angeles River Bridges: Burbank Boulevard Bridges

The Los Angeles River is a concrete-lined channel for most of its 50-mile length between the San Gabriel Mountains and the Pacific. At a few locations, such as just north of the Sepulveda Dam, the river is allowed to meander freely.

The Burbank Boulevard Bridges are three span structures built in 1976. They cross the Los Angeles River just north of the Dam. Their shape is organic, which is very unusual for bridges in California. The piers slope upward and meet a soffit that looks formed by a human hand.

The Dam is also striking, but it was built in 1941 and is much less organic in appearance. These bridges are sculptural, with a style reminiscent of Naum Gabo or Henry Moore. They blend in well with their environment, and are a happy change from the cookie-cutter style of most California bridges.

Los Angeles River Bridges: Burbank Boulevard Bridges by Mark Yashinsky is licensed under a Creative Commons Attribution 3.0 United States License.