Sunday, December 25, 2016

Bridges of Lyon, France: Pont Raymond Barre across the Rhone River

September 2016 (45.7327, 4.8205) Pont Raymond Barre
You might have noticed in last week's blog that there was a shiny new bridge behind the Pont Pasteur. The two bridges are joined on the right bank but are widely separated on the left bank (see Google earth photo below). In that photo we can see the Pont Pasteur and today's bridge (the Pont Raymond Barre) crossing the Rhone and next week's bridges (the Mulatiere Bridges) crossing the Saone with 'La Confluence' between them.
Bridges need to be seen in some isolation to properly admire their form. However, there is too much going on around Pont Raymond Barre. Also, a bridge should flow visually from the piers to the superstructure but on the Pont Raymond Barre that flow is interrupted. There are distracting lines on the back of the piers and a full stop between the pier and the soffit. Actually the bridge looks better from a distance (see the top photo), where the interruptions are less noticeable.
The Pont Raymond Barre was designed by the architect Alain Spielmann whose book "La Resistance de Sites" was reviewed by The Happy Pontist a few weeks ago. The Pontist does a good job of identifying the deficiencies in Spielmann's designs, which may be the result of not challenging the engineer more often.
Actually, the prettiest part of the bridge is up on the deck. The timber walking surface, red sofas, and soaring arches make for an elegant environment to wait for the shuttle.

In the photo below the Pont Pasteur is on the far right, a shuttle is waiting for passengers in the center, and the stairway to the Musee du Confluence is on far left. The approach to the Mulatiere Highway Bridge and Fourviere Hill can be seen in the distance.
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Sunday, December 18, 2016

Bridges of Lyon, France: Pont Pasteur across the Rhone River

September 2016 (45.7333, 4.8208) Pont Pasteur (with the Passerelle de las Paix and the Confluence Museum)
It is a one mile walk downstream from the Perrache Viaduct to the Pont Pasteur along the Rhone. This area, near the confluence of the Rhone and the Saone, has seen less residential development then the rest of Lyon, but plans are being made to build another bridge (the Ponts des Girondins) and also to provide more parks and other amenities for the Girondins Zac (south of the railroad), which is currently mostly industrial buildings.
A bridge was built at this spot in 1914 but it was washed away by a flood in 1918. A three span arch was built in 1923 but it was destroyed during WWII. The current bridge was built in 1950. It is a three span reinforced concrete open spandrel arch bridge (composed of three arch rings) with the arches springing from foundations at water level. The arches also have flat curves that rise only about 25 ft above the water. Consequently, there are no large ships and no movable bridges across the Rhone in Lyon, just barges and pleasure craft. The river has been dammed and there is a system of locks to allow boats to travel along the Rhone (or along adjacent ship channels) from Switzerland 500 miles south to the Mediterranean. More information for those thinking about navigating this river is available from the French Government.
The current Pont Pasteur is 195m (640 ft) long and 18m (60 ft) wide. Pedestrian undercrossings (see photo above) were built in the abutments to allow people to continue walking along the quai since the arches are too low to walk under. This bridge appears to be a favorite hangout for pigeons.
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Sunday, December 11, 2016

Bridges of Lyon, France: Perrache Viaduct across the Rhone River

September 2016 (45.7466, 4.8302) Perrache Viaduct
Continuing downstream past Pont Gallieni we arrive at Perrache Viaduct, a railroad bridge across the Rhone. The bridge was named after the nearby train station (and surrounding district), whose enormous yard can be seen in the Google earth photo in last week's blog. The bridge (and the station) were built in 1856. It is a five span cast iron arch bridge on pile foundations that have been repaired, widened, and strengthened several times. It was bombed twice (by the Allies and then by the Germans) during WWII but it was only partially damaged. After the liberation the U.S. Army used the bridge to carry convoys of heavy vehicles eastward after the retreating German Army.
When looking at the bridge, it isn't hard to identify the newer and older members. The exterior arch on the upstream face (above) appears to be riveted and it supports the deck with steel spandrel columns. The exterior arch on the downstream face (below) is reinforced concrete for two of the spans (as part of a later widening or repair) perhaps because steel was hard to obtain. All of the railroad bridges in this part of France have overhead lines to power the trains.
This is the second railroad bridge that we've studied (we looked at the Viaduc SNCF for the first posting on Lyon). We'll look at several more railroad bridges as we complete our circumnavigation of Lyon and head into the surrounding countryside. I noticed a blog on how to take a train from the Perrache Viaduct to the Millau Viaduct (6 hours and $84) in case anyone is interested. Other trains go to Paris and Rome.
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Sunday, December 4, 2016

Bridges of Lyon, France: Pont Gallieni across the Rhone River

September 2016 (45.7483, 4.8320) Pont Gallieni
The first bridge that was built at this site was part of a plan in 1847 to provide a continuous route through Lyon with bridges across the Saone and Rhone. The current bridge on this east-west route is a three span steel I-girder structure that was built in 1965. The Pont Gallieni was named after a 19th century French military officer, Joseph Gallieni. An earlier bridge was named Pont du Midi but that was changed to Gallieni at his passing in 1916.
In the Google earth photo above we can see the Saone and the Rhone with an elaborate transportation system on the Presqu'ile, the peninsula between the bridges. The highway bridges are to the north and the railroad bridges are to the south. The Pont Gallieni lost two of its traffic lanes to a tram system in 2001.
 The Pont Gallieni has seven steel girders with straight girders on the approach spans and haunched girders on the center span. The girders sit on nicely tapered stone piers. I think stone is Lyon's favorite building material. Exposed stone is used for a walking surface and walls on the quays and no matter what the age of the bridge, it seems to have stone piers and abutments.
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