Portland's Bridges: Ross Island Bridge

Upstream from the much maligned Marquam Bridge is the more appreciated Ross Island Bridge. Perhaps the public found the Ross Island Bridge more likable because the main truss span is in the shape of an arch. It was designed by Gustav Lindenthal (along with the Burnside and Sellwood Bridges) after a bribery scandal involving the original designers. The 1819 ft long truss bridge was built by Booth and Pomeroy for Multnomah County. They constructed the side spans on falsework and then used cantilever construction to build the main span, which is 535 ft long and rises 123 ft above the Willamette River. The bridge includes 29 reinforced concrete approach spans, for a total length of 3700 ft.

The Ross Island Bridge, along with the Burnside and Sellway Bridges, was completed in the mid-1920s, marking the end of a prolific period of bridge building for Multnomah County. Although it's called the Ross Island Bridge, it crosses the Willamette River about 800 ft north of Ross Island. It carries US 26 across the river and connects to a variety of streets and highways in south Portland. This bridge, along with the St Johns Bridge, was given to the Oregon Department of Transportation in the mid-1970s, when the county could no longer afford to maintain it.

Portland's Bridges: Ross Island Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Portland's Bridges: Hawthorne Bridge

There are four movable bridges crossing the Willamette River in midtown Portland. The Hawthorne Bridge is the southernmost of these bridges. It is the oldest lift bridge (built in 1910) operating in the United States and it's the oldest highway bridge and the busiest bicycle bridge in Portland.

The Hawthorne Bridge is a six span, 1382 ft long, truss bridge with a 244 ft long lift span. It has 49 ft of vertical clearance when it's closed and 159 ft when it's open. It replaced the second Madison Bridge, which was built in 1900 and destroyed by fire in 1902 (the bridge connects Madison Street to Hawthorne Blvd. in Portland). The 440 US ton counterweights are suspended from 165 ft tall towers. It was designed by John Waddell who invented the lift bridge (see comments) and designed the nearby Steel Bridge (see the September 12th posting). However, unlike the Steel Bridge, it has only a single deck with two lanes inside the truss and two lanes and wide bicycle lanes/sidewalks outside the truss (widened and restored in 1999). The bridge cost $511,000 and it's estimated to have a replacement cost of about $190 million.

Portland's Bridges: Hawthorne Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Portland's Bridges: Morrison Bridge (2)

One more look downstream at the Morrison Bridge from the deck of the Hawthorne Bridge. The side spans are deck trusses and the approach spans are steel girders. As I mentioned, there are several ramps and connectors that carry vehicles from streets and expressways on and off this bridge. Like the other movable (non-railroad) Willamette River crossings, this bridge is owned by Multnomah County.

The bascule span is usually opened once a day, which is fortunate since the roadway is so heavily traveled. There's about 69 ft of vertical clearance with the bridge closed. The machinery that performs this operation was manufactured by Northwest Marine and Iron Works of Portland and installed in 1957 by US Steel.

It seems like movable bridges aren't built as often anymore, although some unusual movable footbridges have been built lately. Most bridge owners aren't willing to invest in the much higher operating and maintenance costs. The alternative would be long retaining walls or approach spans to lift the crossing high above the water. I'm not sure whether retaining walls or approach spans would be more expensive. It probably varies from place to place. Still, an approach span would be required whenever there are streets that must be crossed over.

As I've previously mentioned, bridge building is a dangerous occupation. Construction of the Morrison Bridge took the life of a Mr. Davies when he was buried by a slide while checking footing reinforcement.

Portland's Bridges: Morrison Bridge (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Portland's Bridges: Morrison Bridge

There have been three Morrison Bridges at this location. The first bridge was designed and built by Charles Swigert of the Pacific Bridge Company in 1887. It was a timber truss bridge with a steel swing span and it was the first bridge in Portland across the Willamette River. It survived the flood of 1894 which rose to the bridge's deck and damaged the motor and railing. It was replaced with a wrought iron and steel swing bridge in 1905. It had a timber deck and carried street cars but no automobiles.

The current Morrison Bridge was built in 1958 at a cost of $13 million. It included an elaborate interchange with ramps for the I-5 and the I-84 expressways. It's a double leaf bascule bridge, similar in appearance to the Burnside Bridge, but with an airport motif instead of medieval battlements. It was designed by Sverdrup of St. Louis and by Moffat and Nichol of Portland and built by the American Bridge Division of US Steel.

Large cofferdams were build for the two main piers. While the east cofferdam was being de-watered, several struts buckled from the increased stress but adjacent struts prevented collapse of the cofferdam. While the new bridge was being built, the east side of the existing bridge was moved to the south and continued carrying traffic. Because the second bridge was kept in service, the west side of the third bridge doesn't connect to Morrison Street.

The third Morrison bridge is 760 ft long, 90 ft wide, and with a  284 ft long double leaf bascule span. The deck of the bascule span was made of grated steel to reduce its weight. The bridge is the largest machine in Oregon with 36 ft tall gears driving the 940 US ton counterweights inside each pier. It carries 50,000 vehicles a day as well as bicycle and pedestrian traffic. Its scheduled for a seismic upgrade in the near future.

Portland's Bridges: Morrison Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Portland's Bridges: Burnside, Morrison, and Hawthorne Bridges

This photo was taken from the Oregon Health and Science University (OHSU) on a hill west of the Willamette River. You take the Portland Tram up to the University Hospital.  I wondered how they handled emergencies, especially if the tram were to lose power, but apparently they have adequate back-up systems. In the foreground are three moveable bridges and above the horizon is Mount St. Helens, which was cone shaped before it erupted in 1980.

We studied the Burnside Bascule Bridge yesterday. The Morrison Bridge is also a bascule bridge, which means the center leaf spans meet at midspan and swing up and down with the help of motors and counterweights (behind the pivot point). The Hawthorne Bridge is the oldest vertical lift bridge still in operation in the United States. We will take a closer look at these two bridges in the next few days.

Portland's Bridges: Burnside, Morrison, and Hawthorne Bridges by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Portland's Bridges: Burnside Bridge

It is appropriate that a movable bridge was named after Dan Burnside since he was instrumental in  having the Willamette River dredged (in 1866) in order to make it a shipping channel. The original bridge at this site (built in 1894) was a swing bridge. When this bridge became outmoded because it was slow to open and close, it was replaced with a faster moving bascule bridge in 1926.

The double-leaf bascule span was designed by Joseph Strauss who later designed the Golden Gate Bridge. The design of the fixed spans was begun by Hedrick and Robert Kremers of Portland. It was completed by Gustav Linderthal after Robert was arrested for bribery and collusion. I don't know what it was like in Portland in the 1920s, but I know that in many places you can't get a bridge built without some bribery and collusion due to corrupt politics. The bridge was built by the Pacific Bridge Company.

The design of the Burnside Bridge included the services of Houghtaling and Dougan Architects of Portland who created a Disney fantasy similar to St. Johns Bridge. The main piers have octagonal towers attached to crenelated battlements that make the bridge resemble a medieval castle. This was part of the City Beautiful Movement that was initiated during the 1893 Chicago World's Fair, and which also influenced the design of several Los Angeles bridges.

One interesting peculiarity of the Burnside Bridge is that the bascule leafs were made of reinforced concrete which made them extremely heavy and required counterweights inside the two piers weighing 1700 US tons. Moreover, the lifting operation is controlled by the operator on the nearby Hawthorne Bridge.

The Burnside Bridge has a center span 251 ft in length that provides 64 ft of vertical clearance when it is closed. It has two 261 ft long steel truss approach spans and 34 steel girder spans for a total bridge length of 2308 ft. The bridge carried streetcars and electric trolleys until the 1950s. In 1995, one of the six vehicle lanes was converted to a bicycle path. In 2002 it became one of the first bridges in Portland to get a seismic retrofit. In 2007 the aging deck was replaced. Bridges are considered to have a 75 year life and the first thing to go is their decks which get a terrible beating, especially due to the heavier trucks currently using our roads.

This bridge provides shelter for an illegal skatepark under its east end. Politicians tend to allow these parks to exist even though the bridge owner now has liability for people using their right of way. In California, we tried to remove a skatepark in Oakland, because the construction of the park covers the bottom of the columns with concrete, which shortens the column's effective length and tends to make them fail in shear during earthquakes. However, the California politicians were more concerned with pleasing the local communities then worrying about an earthquake that might not occur for many years.

Portland's Bridges: Burnside Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Portland's Bridges: Steel Bridge

The Steel Bridge (over the Willamette River in Portland, Oregon) is a very unusual 'telescoping lift bridge' that can raise its lower deck without disturbing traffic on its upper deck and it can raise both decks to allow for the passage of large vessels. In the closed position it provides about 26 ft of vertical clearance. With the lower deck raised it provides 72 ft of vertical clearance. With both decks raised it provides 162 ft of vertical clearance. It has independent counterweights to lift each span.

The Steel Bridge is also unusual for the variety of vehicles that it can accommodate on its two decks. In this photo we can see a light rail train traveling on the upper deck while three diesel locomotives are crossing on the lower deck. The average daily traffic includes 23000 trucks, buses, cars, and motorcycles, 200 light rail trains and trolleys, 40 freight and Amtrak trains, over 2000 bicycles, and uncounted pedestrians. It carries railroad, pedestrian, and bicycle traffic on the lower deck and highway, light rail, and streetcar traffic on its upper deck.

The Steel Bridge was designed by Waddel and Harrington (consultants from Kansas City) with support from the Oregon Railway and Navigation Company and the Union Pacific Railroad. The two railroad companies also built the bridge, which was completed in 1912. It replaced the previous Steel Bridge from 1888 that was so named because it had replaced an even earlier wrought iron bridge.

The Steel Bridge is composed of a 290 ft long steel Pratt truss on each side of the 211 ft long lift span. The superstructure is supported on short concrete piers on caisson foundations. Wikipedia has a nice website for this bridge that includes several drawings of the structure and the lift mechanism.

Portland's Bridges: Steel Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Portland's Bridges: Broadway Bridge

About half a mile upstream from the Fremont Bridge (across the Willamette River) is the Broadway Bridge. It is an unusual Rall-type bascule bridge, which was chosen as the low bidder in a competition. However, the complex mechanism (it rolls back on rails as it lifts) has required frequent repairs and has been more expensive in the long run.

The bridge was designed by Ralph Modjeski and built by the Pennsylvania Steel Company over two years at a cost of $1.6 million. It had the world's longest double leaf bascule span when it was completed in 1913.

The main piers are reinforced concrete faced and topped with granite. The approach piers are 12 ft diameter concrete-filled steel pipes tied together with cross-bracing. A 278 ft double-leaf bascule span is supported on the main piers and crosses over the shipping channel. It provides 70 ft vertical clearance when closed and is opened about once a day. An operator's house is above each of the main piers (on the other side of the bridge). The approach spans are steel, camelback trusses. A reinforced concrete ramp on the west side goes over Union Station and carries traffic on and off the bridge. A similar ramp on the east side goes over Highway 99 and light rail tracks.

The bridge is 1742 ft long and 70 ft wide. It has two lanes of traffic in each direction and two broad sidewalks. It carries about 2700 vehicles and 1200 bicycles a day. It has been frequently repaired and renovated over the years. The concrete deck was replaced with a steel grating in 1948 to make it easier to lift. The steel deck was replaced with a fiber-reiforced composite material in 2005.

I'll just mention that Portland, Oregon is a very nice, attractive city with a very efficient transportation system. The area around the Willamette River is particularly pleasant and attracts large crowds on the weekends.

Portland's Bridges: Broadway Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Portland's Bridges: Fremont Bridge (2)

The Fremont Bridge crosses the Willamette River several miles upstream from St. Johns Suspension Bridge.

If you look closely at today's photo, you can see St. Johns Bridge under the Fremont Bridge. The Burlington Northern Railroad Bridge 5.1 sits between them, but I think it must be obscured by a bend in the river. It was originally a swing bridge that was converted to a vertical lift bridge in 1989.

We previously looked at the Fremont Bridge on February 17, 2009. Although these through arch bridges are often built as cantilever structures that are held back with towers and cables, the center span of this bridge was built in California, taken apart and reassembled at Swan Island. put on a barge for the 1.7 mile trip to the bridge site, and lifted onto the 'below-deck' part of the bridge.

The Fremont Bridge is a double-deck structure with four lanes of traffic in each direction. At 1255 ft it has the longest arch span in Oregon. We previously studied the Lupu Bridge in Shanghai which will shortly lose its title of having the longest arch span to the Chaotianmen Bridge (with a 5712 ft span), which is also in China.

Portland's Bridges: Fremont Bridge (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Portland's Bridges: St. Johns Bridge (3)

The back spans of St. Johns Bridge are supported on tall reinforced concrete piers in a Gothic arch shape similar to its towers. They also are reminiscent of the towers on the Brooklyn Bridge. Perhaps this shape, originally used for the churches of medieval Europe was consciously chosen by bridge engineers to add importance to their work.

This bridge was named after a saint and the piers are in Cathedral Park, so the church-like architecture could be appropriate. However, I think that bridge engineers like Roebling, Linderthal, Steinman, and McCullough were saying that big bridges were the churches of the industrial age because they best express our yearning for the spiritual. Perhaps there's also a touch of American Transcendentalism in using religious icons for structures that span rivers, canyons, valleys, and other landscapes that suggest a deeper meaning or revelation in nature.

Portland's Bridges: St. Johns Bridge (3) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Portland's Bridges: St. Johns Bridge (2)

St. Johns Bridge was designed by David Steinman who had been an assistant to Gustav Linderthal on the 1917 Hell Gate Bridge (see blogs of July 20th and 21st). Those bridges were also designed with a concern for their appearance that was separate from their function. As a result of this excessive decorativeness, the bridge resembles a ride at Disneyland.

The bridge was built in the St Johns neighborhood of northern Portland, hence its name. It's the only suspension bridge in Portland and its completion ended ferry service across the Willamette River. The main span is 1207 ft long and its total length is 2067 ft. The suspension cables are composed of 91 - 1.5 inch diameter steel rope strands that were manufactured and pulled across the river by John A. Roebling and Sons Inc.

Multnomah County was reluctant to build a bridge so far from downtown Portland and so the local residents had to lobby hard to get the $4.25 million bond approved in the 1928 election. The Great Depression began soon after construction began and so the bridge served as secure employment for the region. Perhaps that explains why the bridge was $1 million under the budget when it was completed. It was originally owned by Multnomah County but by the 1970s the county couldn't afford to maintain the bridge and ownership was eventually transfered to the State of Oregon. From 2003 through 2005 the bridge was extensively renovated (at a cost of over $38 million).

Portland's Bridges: St. Johns Bridge (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Portland's Bridges: St. Johns Bridge (1)

The Willamette River flows northward for 187 miles through northwestern Oregon and empties into the broad Columbia River. A little south of the Columbia is the City of Portland with the Willamette flowing through its center and crossed by many bridges. When I first heard the river's name, I assumed it was named after the British monarch William of Orange and was surprised that it's name derived from a Clackamas Indian village.

St. Johns Bridge is a highly ornamented suspension bridge that was built in 1931 about six miles upstream from the mouth of the Willamette River. It's hard to believe that the modern George Washington Bridge across the Hudson River was built in the very same year. However, Oregon bridges have a Gothic aesthetic far removed from the clean lines of bridges being built in New York. Its the tallest bridge in Portland with 408 ft tall towers and 205 ft vertical clearance over the river. We'll take a closer look at the bridge tomorrow.

Portland's Bridges: St. Johns Bridge (1) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.