Willamette River Crossings: Minto Island Bridge in Salem, Oregon

July 2017 (44.9384, -123.0454) Minto Island Bridge

A little south of the Center Street Bridge is the recently opened Minto Island Pedestrian Bridge. The bridge doesn't actually cross the Willamette River but crosses the Willamette Slough on the west side of the island. This project took almost 10 years from the initial proposal to the completed bridge.

In 2008 several design options were studied. In 2010 a 600 ft long tied arch with a 14 ft wide deck was selected. In 2011 the city obtained a permit to cross over the slough. In 2012 OBEC Consulting was hired to complete the design of the bridge. Construction (by Legacy Contracting) began in 2015 but delays set the project back a year. Even small delays can ruin schedules since work in sloughs are limited to a few months out of the year. The bridge was finally opened in May of 2017.

The $10 million in funding came from the City of Salem, the Oregon DOT, and smaller groups such as Friends of Two Bridges. The bridge provides access between Salem's Riverfront Park and Minto Island. Part of the project was providing landscaping (by Greenworks) to integrate the bridge into the park. The city is anticipating the bridge's role in future events such as a yearly marathon.

The bridge is a fairly simple structure. The two arch ribs are one inch thick circular sections, 30 inches in diameter, that rise 44 ft above the deck and extend 327 ft between the triangular abutment/piers. The concrete deck acts as a tie to restrain the arch ribs. The arches are inclined at about a 30 degree angle from vertical, perhaps to provide lateral resistance (no cross-bracing is provided). Single cable stays support the deck and are attached to plates welded to the steel arches and securely anchored into the concrete deck.

The bridge is reasonably attractive. A concrete deck for a steel arch bridge is a little annoying. Also, the black railing appears to be added without much thought to the aesthetics. The bridge isn't innovative but it makes a pleasant addition to the city's bridges.

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Sacramento County, California Bridges: Curtis Park Pedestrian Overcrossing over the Union Pacific Railroad

May 2017 (38.5428 Degrees, -121.4838 Degrees) Curtis Park POC

There's a great deal of interest by bridge engineers in developing Accelerated Bridge Construction (ABC) techniques to minimize the time working in the right-of-way of railways and roadways. A good example of these techniques was in the construction of the Curtis Park POC over the Sacramento Regional Transit Light Rail and Union Pacific Railroad tracks. A 174 ft long tied arch was chosen because it could be picked up and placed on its piers in just a few minutes and because it was long enough to span over the Union Pacific Railroad Yard (the Sacramento Light Rail tracks were spanned by the adjacent precast concrete slab).

As can be seen in the photos above and below the 50 ton arch, which was sitting on the ground on 10th Avenue, was picked up at the top of the arch ribs and swung 180 degrees onto the piers.

A tied arch is a good choice for this project. Steel girders would have been too deep and would have interfered with the 23.5 ft vertical clearance required by the railroad. A tied arch has its supporting members above the deck where it doesn't interfere with traffic below.

Note the long ramps that zigzag along the sides of the bridge to carry pedestrians and bicyclists onto the arch structure. In the United States the Americans with Disabilities Act (ADA) is taken very seriously. I noticed a lot of grinding of the ramps to meet ADA requirements on the grades.

This $6 million bridge opened in April and allows pedestrians and cyclists on the east side of the tracks to get to Sacramento Light Rail, Sacramento City College, and Freeport Blvd. 

Note that the arch ribs support the deck with steel cables attached to the ties (in the photo below). After the arch was placed on its supports a concrete deck was poured, cured, and the bridge was then opened to the public.

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Contra Costa County, California Bridges: Iron Horse Trail POC across Ygnacio Valley Road

February 2014 (37.90707 Degrees, -122.05778 Degrees) Ygnacio Valley Road POC

The next bridge on the Iron Horse Hiking Trail is a more traditional steel arch. The Ygnacio Valley Road Pedestrian Overcrossing is a 550 ft long viaduct with a 136 ft long tied arch main span and with truncated deck arches for the side spans.

This bridge was built in 1998 by C. A. Rasmussen and designed by Santina and Thompson. However, unlike yesterday's Treat Blvd OC, there are few postings on the internet other than the always reliable Bridgehunter Website with photos by Craig Philpott.   

Today's bridge is more utilitarian than the Treat Blvd POC. The arch ribs are parallel steel box girders with lots of tubular steel cross-braces between the ribs.  The deck is wider but it's hanging from steel rods with turnbuckles. The dark fence imparts a feeling of claustrophobia while crossing over the bridge.

Contra Costa County, California Bridges: Iron Horse Trail POC across Ygnacio Valley Road by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Contra Costa County, California Bridges: Robert I. Schroder Pedestrian Overcrossing across Treat Blvd

February 2014 (37.92655 Degrees, -122.0546 Degrees) Iron Horse Trail Bridge

One of the nicest bridges on the Iron Horse Hiking Trail is the Robert I. Schroder Pedestrian Overcrossing in Pleasant Hill. This tied arch bridge was designed by Arup of San Francisco, it cost $6.8 million, and it was completed in October of 2010. It's an 800 ft long steel structure with a concrete substructure and a 10 ft wide deck. The bridge has a steel box girder superstructure supported by outward-inclining steel arches that rise 42 ft above Treat Blvd. 

Each arch rib is composed of three steel pipes bolted to wedge-shaped steel diaphragms. The ends of the steel arch ribs are connected with a steel cross brace and anchored into cylindrical reinforced concrete legs that are part of a single large foundation. The main span is 240 ft long and supported by pairs of crossed cables (40 ft apart) hanging from the wedge-shaped steel diaphragms.

This is an efficiently designed structure. A cylindrical concrete column is placed squarely between the concrete legs of the arch ribs. The steel diaphragms brace the pipe elements of the arch ribs and also carry the weight of the deck. In the past arch ribs were parallel or inclined together into a basket-handle shape but now outward inclining arch ribs seem to be popular.

My friend Richard Hartzell mentioned that the bridge is on a horizontal curve and so each arch rib has a different slope to accommodate the curve, which must have been difficult to analyze and design. More information about this bridge can be found on the Arup website.

Contra Costa County, California Bridges: Robert I. Schroder Pedestrian Overcrossing across Treat Blvd by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Tokyo Prefecture, Japan's Bridges: Kachidoki Bridge across the Sumida River (8)

September 2013 (35.6623 Degrees, 139.7747 Degrees) Kachidoki Bridge

Once we arrived back in Tokyo we went for a walk to see the Tsukiji Fish Market, where fresh tuna are bought and sold for thousands of dollars. Unfortunately, it was Sunday and the market was closed. However, our walk did give me another opportunity to photograph the Kachidoki Bridge across the Sumida River. This bridge has three river spans with tied arches on the ends and a double bascule span in the center. The Sumida River in Tokyo is like the Thames River in London with a movable bridge near the entrance into the city.

Since I included a Japanese woodblock print in yesterday's blog on Mt. Fuji, I thought I'd show another by one of my favorite contemporary artists, Osamu Sugiyama of the Tsukiji Fish Market, the Kachidoki Bridge, and the Sumida River in bright sunlight. 

Tokyo Prefecture, Japan's Bridges: Kachidoki Bridge across the Sumida River (8) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

Kagoshima Prefecture, Japan's Bridges: 5: Gionnosucho Footbridge

September 2013 (31.6046 Degrees, 130.5705 Degrees) Gionnosucho Footbridge

The artificial island of Gionnosucho was build just offshore from Kagoshima. It includes a baseball diamond, some apartments, and a Nissan dealership. There are four bridges connecting the island to the mainland (as seen in the Google earth photo below). Two highway bridges carry Route 10 on and off the island. There are also two footbridges, a modern tied arch bridge and the Tamaebashi stone arch, which we'll study tomorrow.

The Gionnosucho Footbridge is a 110 ft long tied arch structure composed of tubular steel arch ribs connected by cross-braces. Steel rods (with turnbuckles) hang from the arch ribs and support the deck on floor beams. Tubular steel railing is supported on the steel ties and have large square end posts. The superstructure rests on concrete abutments. The photos were taken in the late afternoon, which must have been low tide.

Kagoshima Prefecture, Japan's Bridges: 5: Gionnosucho Footbridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.

Niigata, Japan's Bridges: Yonahime Bridge on Route 8

August 2007 (37.3168 Degrees, 138.4348 Degrees) Yonahime Bridge

This is a 120 m long through truss arch, crossing over a narrow canyon south of Kashiwazaki. We saw a landslide scarp on the uphill side of this bridge, but since the bridge is founded on piles, it was probably strong shaking that caused it to rack during the earthquake.

When we visited the bridge (on Aug. 4^th) we saw many of its members had buckled and some of its connections were damaged along with its bearings.  Still, the bridge remained in service (jacked up and sitting on metal boxes), which shouldn’t be a problem unless another strong earthquake occurs. This very common bridge type is sensitive to shaking, because the struts and bracing can’t resist compression. A deck arch bridge immediately to the north was undamaged by the earthquake.  

It might be possible to redesign the Yonahime and other tied arch bridges for large earthquakes by supporting it on isolation bearings.  Certainly, these fixed bearings, which we saw damaged on several of the longer span bridges, are a lot of trouble to replace.

Niigata, Japan's Bridges: Yonahime Bridge on Route 8 by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Tokyo, Japan's Bridges: Hesei (平成橋) Bridge across the Naka Gawa

March 2012 (35.685 Degrees, 139.846 Degrees) Hesei Bridge

As we paddled east from the Onagi into the Nakagawa, I took a quick photograph to the south of the Hesei (平成橋) Bridge, a single span tied arch structure with 'I' girder hangers and box girder arch ribs. This bridge was built in 1994 and spans 105 meters across the Nakagawa. 


The bridge acts as an evacuation route, perhaps from floods. Note in the Google Earth photo below that it is the last bridge across the Nakagawa before the Arakawa Flood Gates.  

Tokyo, Japan's Bridges: Hesei ((平成橋) ) Bridge across the Naka Gawa by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Tokyo, Japan's Bridges: Kohoku Bridge across the Arakawa

March 2012 (35.764 Degrees, 139.761 Degrees) Kohoku Bridge

Downstream from the big Goshiki Zakura Bridge is the diminutive Kohoku Bridge. The alignment of the two bridges is shown in the Google Earth photo from my May 5th blog.  Route 307 crosses the Sumida River over the Toshima Bridge and then turns to the north and crosses the Arakawa on the Kohoku Bridge.

The Kohoku Bridge was completed in 1967. It is a long steel girder bridge with a steel tied arch span across the shipping channel. A view of the west approach spans is shown below. It's composed of simple spans on big pier walls. Note the floral motif on the railing with the lampposts on the outside.

Japan's Bridges: Kohoku Bridge across the Arakawa by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 United States License.

Tokyo, Japan's Bridges: Toshima Bridge across the Sumida River

(35.767 Degrees, 139.748 Degrees) Toshima Bridge

Another bend in the river and another arch bridge. This interesting structure was completed in 2007. It's a 350 ft long pony arch with two big box girders under the deck (see photo below). If you look closely you can see cables holding the end of the bridge to the ground.

There is often an effort for bridges in Japan to match the color and texture of the surrounding buildings, which this bridge has successfully accomplished. In fact it won several awards for its appearance, shape, color, and details.

Tokyo, Japan's Bridges: Toshima Bridge across the Sumida River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Tokyo, Japan's Bridges: Toyoshima Bridge across the Sumida River

March 2012 (35.763 Degrees, 139.755 Degrees) Toyoshima Bridge

This is a nice view of the Sumida River with fishing poles tied to the railing. The river used to be too polluted for fishing. However, we are near the river's source which may bring cleaner water and more fish. This photo also provides another view of the Metropolitan Expressway along the river's southwest bank.

There are two Toyoshima Bridges that cross this part of the Sumida River (we'll look at the other bridge tomorrow). This bridge is a one span tied arch bridge on a skew that is 350 ft long and completed in 2001. It replaced a steel Gerber Bridge built in 1960 that slowly deteriorated due to ground settlement along the banks.

Tokyo, Japan's Bridges: Toyoshima Bridge across the Sumida River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Tokyo, Japan's Bridges: Kodai Bridge across the Sumida River

March 2012 (35.754 Degrees, 139.763 Degrees) Kodai Bridge

The next bridge across the Sumida is a single span tied arch that was completed in 1992. It's called the Kodai Bridge after the geographical name for this part of Adachi Ward. It replaced a bridge that was built in 1933 (during the building boom following the Great Kanto Earthquake). It is a 400 ft long bridge with two traffic lanes and sidewalks. It carries Hakusan Road from the south across a bend in the Sumida and then the road turns west and runs parallel to the Arakawa.

The City of Tokyo apparently likes painting bridges with bright colors including chartreuse. I think the lamps on the bridge must have been taken from the older bridge since they don't look like they were made in 1992.

Tokyo, Japan's Bridges: Kodai Bridge across the Sumida River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Tokyo, Japan's Bridges: Otake Bridge across the Sumida River (2)

March 2012 (35.753 Degrees, 139.789 Degrees) Otake Bridge

Another view of the Otake Highway Bridge. It's a continuous three span bridge with an arch supporting the center span. If you look closely you can see 'belvederes' placed before and after the arch, just past the hammerhead bents.

Tokyo, Japan's Bridges: Otake Bridge across the Sumida River (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Tokyo, Japan's Bridges: Otake Bridge across the Sumida River (1)

March 2012 (35.753 Degrees, 139.789 Degrees) Otake Bridge

I passed another utility bridge before reaching the Otake Roadway Bridge. It's a 427.5 ft long steel tied arch built in 1994. Unlike the Suijin Bridge, the Otake is a simpler arch bridge with vertical cable hangers supporting the floor beams. The bridge carries Highway 313 north to Highway 461 and across the Arakawa.

Tokyo, Japan's Bridges: Otake Bridge across the Sumida River (1) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Tokyo, Japan's Bridges: Ayase Bridge across a Canal along the Sumida River

March 2012 (35.740 Degrees, 139.816 Degrees) Ayase Bridge

A kilometer upstream from the Suijin Bridge is a short canal that connects the Sumida to the Arakawa. The Metropolitan Expressway turns east at the canal and is supported on big outrigger bents. Under the expressway is the Ayase Bridge that carries Route 461 along the east bank of the Sumida River. The Ayase Bridge is a 200 ft long tied arch bridge with four traffic lanes and wide sidewalks.

Ayase Bridge across a Canal along the Sumida River by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.