Great Britain: Pulteney Bridge in Bath

I was hoping to enjoy a bath or swim in the mineral springs of Bath. However I was disappointed when my money just paid for the privilege of looking at some Roman ruins! Actually, I had arrived in Bath too early (or too late). In 2006 the Thermae Bath Spa opened with bathing and swimming facilities.

The thermal springs of Bath are a surprising phenomena since hot springs usually occur near the edges of tectonic plates (the UK is not seismically active). I remember after an earthquake near Paso Robles, California (in 2003) the thermal springs were disturbed and hot water gushed onto the streets for several months.

The Pulteney Bridge was completed in 1773. At that time, the upper class enjoyed vacations to Florence and Venice and became fond of the pretty river bridges lined with shops. The Pulteney Bridge has shops along both sides and a road (soon to be turned into a footpath) down the middle. Over time it was damaged by floods, by widenings, and by the shops that hung over the sides. The bridge was restored to something like it's original design in 1951 with further work done in 1975. It is is now a national monument and designated an English Heritage site.

I took this picture while standing on the Parade Bridge over the River Avon and looking north at Pulteney Bridge. Just downstream is a parabolic-shaped weir and the Bath Abbey.

Great Britain: Pulteney Bridge in Bath by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License.

Great Britain: Town Path Bridge in Salisbury (2)

One last photo of Salisbury and then we'll move on. This is another view of the three-span Town Path Bridge across the River Nadder. The bridge has a long embankment on the west (far) side that juts into the river (retained by masonry wingwalls) and then rises over the river into Salisbury.

The Nadder begins as springs and streams in south Wiltshire and flows northeast until it meets the River Avon in Salisbury.  The 32 km river is popular for its clear water, abundance of trout, and the unspoiled meadows along it's banks.

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Great Britain: Water Lane Bridge in Salisbury

Another quaint one span bridge in Salisbury. This structure carries Fisherton Street over a tiny tributary of the River Avon.  It looks like a through girder bridge made out of blocks of stone. Or maybe it's just a reinforced concrete slab with big stone pedestals. Note the pretty green abutments.

Salisbury is quaint. Across Fisherton Street is a bicycle shop, an Indian restaurant, and a philatelist (now a delicatessen). Water Lane is a footpath along the tributary that is lined with shops.

In medieval England, Salisbury was an important center for the wool industry. It survived plagues and rebellions in the 17th century, but the wool industry went into decline. Today its main industry is tourism.

Great Britain: Water Lane Bridge in Salisbury by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Great Britain: New Canal Footbridge in Salisbury

Another pedestrian bridge across the River Avon just south of the Fisherton Street Bridge.

In yesterday's blog I wondered if a steel girder bridge could have a large camber (the Happy Pontist said aye). Today's steel bridge has an even bigger camber! Actually, this bridge is like one of those deck-stiffened arches designed by Robert Maillart (only made of steel instead of concrete).

As we saw yesterday, the bridge's handrail matches the railing used along the nearby paths and houses. However, no child could fall between the closely-spaced bars on today's bridge.

This is a nice area of Salisbury with pretty homes and a path along the river. We can see the Crane Bridge in the distance. I wonder if these huge homes were ever owned by a single family? I would imagine that today, four or five families live on every floor.

Great Britain: New Canal Footbridge in Salisbury by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Great Britain: Bishop's Mill Bridge in Salisbury

I couldn't find any information about this bridge. Its in the middle of town near the Clock Tower (originally a prison) and the Town House Inn (now called the King's Head).

Because of the dark color, I originally thought the deck was supported by steel girders. However, because of the large camber I'm now thinking it must be a cast-in-place reinforced concrete bridge.

I like the metal railing on this bridge (that continues along the sidewalk). I also like the little masonry abutments. Looking downstream (along the River Avon) is the big, Fisherton Street (vehicular) Bridge.

Salisbury is very pretty (with beautiful bridges, buildings, houses, quay walls). Stonehenge is just north of town (along with neolithic burial mounds) and the area has so much history that it gives an added dimension to one's surroundings.

Great Britain: Bishops Mill Bridge in Salisbury by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Great Britain: Crane Bridge in Salisbury (3)

A last look (from the downstream side) at the Crane Bridge. I never understood why they put cutwaters on both sides of a bridge. When you're so far from the sea the chances of the river flowing upstream should be zero.

Unlike the upstream face, all of the cutwaters in this photo are the same size. The facing stones were reused (after the bridge was widened) so it looks similar to when it was first built. This late medieval bridge was constructed with wooden forms to support the arches until the keystones and facing stones were in place.

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Great Britain: Crane Bridge in Salisbury (2)

A closer look at the Crane Bridge. The photo shows the facing stones acting as a retaining wall for the embankment. Also, the closest cutwater is much taller for some reason. It looks almost like a boat ramp beside the bridge, except the arches look too small for anything bigger than a kayak.

Pools of algae have collected in front of each pier and the bridge is covered in lichen. The wet English climate appears to be ideal for a variety of plant life.

While doing research for this article, I found several bloggers complaining about being harassed by landowners while paddling on the Avon. In the U. S. all navigable waterways are owned by the public. In England the public has the right to use established footpaths but no such right exists for traveling on rivers that pass through private land. However, an act by King Charles II may have given such rights to the public on the River Avon.

The Crane Bridge is a couple of blocks to the northwest of the ancient Salisbury Cathedral. The Town Path Bridge is a couple of blocks further to the west. The ancient town of Harnham and the St Nicholas Bridge that was built in 1230 is just south of the pasture to the west. The Nadder, the Ebble, the Wylye, and the Bourne Rivers, all tributary to the Avon, flows south to Dorset and the sea.

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Great Britain: Crane Bridge in Salisbury

Salisbury was an important trading center. There are bridges dating back to the 13th century that were used by farmers for getting their goods across the rivers to market.

The Crane Bridge was built in the 15th century and later widened to two lanes with sidewalks. Four stone arches with cutwaters cross the River Avon a little north of Salisbury Cathedral (with the world's tallest medieval steeple). Solid parapets sit atop the stone spandrels.

The bridge (and the street) were named after Crane House that once stood nearby. Note that quay walls have been built, perhaps to stem erosion and allow construction along the river.

We'll take a closer look at this old bridge tomorrow.

Great Britain: Crane Bridge in Salisbury by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Great Britain: Town Path Bridge in Salisbury

Salisbury is at the confluence of five rivers in the southeast corner of Wiltshire County (about 70 miles west of London). It's an amazingly green place with a number of interesting bridges.

The Town Path Bridge is a continuous three span timber structure on masonry abutments and trapezoidal concrete piers. The two timber beams of the superstructure are haunched with short end spans and a long center span over the River Nadder. They look like 100 ft long glulam beams that were treated to survive the wet environment. I wonder how they were able to transport such long elements to the bridge site? The beams support five foot high timber handrails and a timber deck.

Although I couldn't find much information on the bridge, I would guess that it is about 30 years old. Its on the path between Harnham and Salisbury that goes through a large pasture filled with sheep. I think this is a very handsome footbridge that blends in well with the heavily wooded site.

Great Britain: Town Path Bridge in Salisbury by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Great Britain: Queen's College Bridge in Cambridge (2)

This is my last photo of the River Cam (a closer view of the Queen's College Bridge). I had gone to Cambridge (straight off the plane from California) to give a talk on the seismic design of bridges. As dusk approached, I was anxious to rejoin my family who were in London. I couldn't find a convenient footpath along the river, and so I made a hurried departure for the next train into London.

If you are interested in seeing the other bridges across the River Cam, Wikepedia has a good website. The Bridgemeister also shows a number of bridges. Perhaps, one day I'll be able to sit in a punt and photograph the Coe Fen, the Crusoe, the Darwin College, the Garret Hostel, the Magdalene, the Jesus Lock, and the many other bridges that cross the River Cam.

This must be a most docile river since it flows along the back steps of Cambridge University. It's less than 100 ft wide and would only require a few feet of additional head to flood most of the University.

The Queen's College Bridge seems to have obtained some improvements since the 18th century. It looks like rubber mats now protect the the wooden deck. A timber bridge must be well-made to withstand the stomping feet of adolescents for a hundred years.

Great Britain: Queen's College Bridge in Cambridge (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Great Britain: Queen's College Bridge in Cambridge

This is an odd bridge. One end is supported by the President's Lodge, which is the oldest building on the River Cam (built in 1460). It's called the 'mathematical' bridge because it's design was claimed to allow one to remove any member without affecting it's stability. It was also said to be based on a design by the 16th century Italian architect Andrea Palladio.

The story that it was designed by Isaac Newton, that it was built without nails or connectors, that the design came from China, that the students took it apart and then couldn't reassemble it, etc. are all apparently untrue.

It was designed by William Etheridge and originally built by James Essex in 1749. The current bridge was built to the same design in 1905 but in teak instead of oak. It is an interesting design, with long members fanning out to form tangents to the arch with short radial members that tie the bridge together.

A much longer article about this interesting bridge can be found at The Bridge in Winter on the Internet.

Great Britain: Queen's College Bridge in Cambridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Great Britain: King's College Bridge in Cambridge

Cambridgeshire County is about 60 miles north of London. It includes Cambridge University with the River Cam running through it. There are many interesting bridges crossing the Cam, but unfortunately I only photographed a few of them. I couldn't find a convenient footpath along the river, which l typically use for looking at bridges. Apparently most people find it more convenient to stand on the back of a small boat (a punt) and push with a long pole while viewing the Cam.

King's College, Queen's College, and several other Colleges at Cambridge have pedestrian bridges named after them that cross the Cam. The first King's College Bridge was built on this site in the 15th century and the current bridge was designed by William Wilkins in 1818. It's a single span, filled spandrel stone arch with a solid parapet and paving stones for a deck. You can see under the arch (in the distance) the 1639 Clare College Bridge with its three spans.

A text I use for UK bridges, The National Trust Book of Bridges refers to the bridge's style as Classical. This usually means the design has shapes reminiscent of those used by the ancient Greeks or Romans. Maybe the use of the arch was picked up from the Romans after the Middle Ages. Or perhaps the author is referring to a style that was less ornate and more functional?

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Great Britain: West India Quay Footbridge (3)

I wanted to write one more blog to say goodbye to Canary Wharf. My closing shot is from the deck of the West India Quay Footbridge. There are many more interesting bridges in the area than I had time to photograph.

The Happy Pontist said the developers of Canary Wharf had too much freedom, resulting in a 'dog's dinner' with an occasional nicely designed bridge. That was also my impression from the afternoon I spent walking around.

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Great Britain: Glengall Bridge

The Glengall Bridge is a pedestrian crossing at Millwall Dock on the Isle of Dogs. This bridge carries Pepper Street across a north-south channel in an area of five and six story condominiums. The odd thing about the Glengall Bridge is that it's almost identical to the structure in Van Gogh's painting Bridge at Arles in Southern France.

The Bridge at Arles was a hand-operated lift bridge. The beams at the top of the towers were weighted so they could swing up (over the channel), lifting the bridge deck out of the way (and blocking the roadway).

The Glengall Bridge isn't as evocative as the Bridge at Arles. Still, it's amusing once you are aware of the resemblance. However, I don't see a mechanism on the Glengall Bridge for lifting the deck. Perhaps it's not a working copy.

There's a lot of information on The Bridge at Arles on the Internet. I found an interesting blog by John Vanderslice that includes a photo of the bridge in the 'up' position.

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Great Britain: Canary Wharf DLR Station

Our idea of what's a bridge is stretched by railway platforms. Most bridges are long and thin but platforms are short and wide.This is particularly true for the Canary Wharf DLR Station which includes six platforms serving three sets of tracks on three parallel structures. However, I think that railway platforms are bridges since they are part of long structures that temporarily change their shape to allow passengers to get on and off the trains.

The nicest part of the station is not the familiar DLR bridges with their distinctive blue barrier rails, but a beautiful elliptical arch over the tracks. The Canary Wharf DLR Station was opened on November 1991. It's a short ride between the West Indian Quay DLR Station and the Heron Quays DLR Station. It's also next to the Canary Wharf Tube Station and the Canary Wharf Railway Station, each of which serves a different railroad.

I must be standing at one of the nearby stations while taking this photograph. At least, I don't think I would be standing on a third rail track that carries a train every five minutes. However, railroad bridges are usually designed with a walkway so that passengers can safely exit the train if it stops running.

Great Britain: Canary Wharf DLR Station by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Great Britain: Aspen Way Dockland Light Rail Bridge

The Dockland Light Rail (DLR) tracks leave Poplar Station and turn to the southwest on an embankment supported by handsome red retaining walls. The tracks continue on a long single-span steel through plate girder bridge over Aspen Way. The bridge deck is composed of precast concrete slabs supported on floor beams attached to the bottom flange of the plate girders. The through girders are supported by a two column bent on each end at a high skew. Past this bridge some of the tracks go south towards Heron Quays and some head west towards London.

The most distinguishing feature of the elevated tracks south and west of the Aspen Way DLR Bridge is the blue railing attached to the sides of the slab with square steel plates. The orange of the concrete and the blue of the railing is what you immediately recognize as the Dockland Light Rail.

The people in the communities surrounding Canary Wharf and Docklands live in an uneasy peace with the developers. They once sued them for interfering with their TV signals and lost. Hopefully, the re-development of this area has provided some jobs to the surrounding communities that were getting poorer after the closing of the ports and warehouses.

Its strange that tree names are so popular in an area with so few trees. The bridge crosses Aspen Way next to the town of Poplar but I don't see any Aspens, Poplars, or any other tree except a few clustered in parks. The great forest that once blanketed England has departed, although you can see that a few trees in wooden boxes were placed along the far quay.

Great Britain: Aspen Way Dockland Light Rail Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Great Britain: Docklands Pontoon Bridge

I'm probably giving this bridge the wrong name, but since it no longer exists, it may not matter. Pontoon (floating) bridges are often used as temporary structures and so perhaps it had served its purpose. It's not as fancy as the nearby West India Quay Footbridge which has been compared to a 'water skater insect' due to its visual grace. This bridge looks more like a utilitarian platform to get pedestrians across a channel in Canary Wharf.

The pontoons are big, flat metal boxes with cables to keep them in place. The superstructure is attached to the pontoons with tubular steel members arranged in a 'W' shape. The superstructure has a deeper section at midspan supported by little cable-stayed towers over the pontoons.  The approach spans are supported by simple through trusses. My son Aaron can be seen in this photo standing on the deck.

Pontoon structures are an interesting class of bridges. They are a good idea in theory, but they sometimes have problems in practice. The first recorded use of a pontoon bridge was in China in the 11th century B.C. They are often used by the military as a quick way to get across a river. The Persians apparently liked them and built famous pontoon bridges to pursue the Greeks across the Bosporus and across the Hellespont. Usually they are carried by an army and removed after they have crossed (to make it harder for the enemy to follow). My experience with them was occasionally driving on the Lake Washington Floating Bridge in Seattle before it sank during a storm in 1990.

Great Britain: Docklands Pontoon Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License.

Great Britain: Heron Quays Dockland Light Rail Bridge (2)

A closer look at the Heron Quays Dockland Light Rail (DLR) Bridge. I'm standing on another pedestrian pontoon bridge, but I don't think it still exists. At least I don't see it on Google Earth. It must have been removed when they built a shopping center next to the rail station.

This branch of the DLR goes under the beautiful roof of the Canary Wharf DLR Station, under the Thames, and eventually through Greenwich before ending at Lewisham.

Great Britain: Heron Quays Dockland Light Rail Bridge (2) by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Great Britain: Heron Quays Dockland Light Rail Bridge

We are looking at the elevated Dockland light rail system. It was developed to provide train service between London and Docklands, which includes Southwark, Greenwich, and much of the original Port of London.

The elevated structure is a haunched steel girder superstructure supported by four column bents attached to integral steel bent caps with steel bearings. Timber fenders protect the caisson foundations.

The original cranes that were used to unload cargo at the port have been retained but are no longer in use. We can see Heron Quays Station above the bridge (supported by cable stays). This whole area has changed a great deal since this photo was taken in 2001. The station was moved to provide access to a shopping center and to accommodate more train tracks. In 2006, more than 60 million passengers traveled along the 19 miles of track.

Great Britain: Heron Quays Dockland Light Rail Bridge by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Great Britain: Poplar Station Walkway

In this photo I'm standing at the north end of Canary Wharf looking toward the ancient hamlet of Poplar. The steeple of the early 19th century All Saints Poplar church can be seen in the background.

This bridge reminds me of one of The Happy Pontist's 'copycat coils.' It's a high level walkway to a light rail station over a highway.  There are a variety of elements (white staircases, a grey tower with cable-stays, a greenish tube) that don't seem to be very happy together.

Note the ornate ramp and bridge (in shadow) on the left side of the photo and the neo-Georgean buildings. This mixture of styles (similar to the different elements on the bridge) are hard on the eyes. Perhaps the walkway will get along better with it's neighbors over time, but its hard for me to imaging it being around that long.

Great Britain: Poplar Station Walkway by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

Great Britain: West India Quay Footbridge (2)

Another look at the West India Quay Footbridge. It's hard to imagine this area when it was mostly ships and warehouses for the distribution of sugar and rum from the West Indies (a chain of Caribbean Islands that includes earthquake-ravaged Haiti). Columbus thought he had found a new route to Southeast Asia and so they called the region the West Indies after they realized his mistake.

The Happy Pontist correctly stated that the bridge pontoons are anchored to the channel bottom. This area is affected by tidal currents so the anchorage must keep the bridge from lifting off the quays during high tide.  He also correctly named this bridge. I was originally reluctant to give the proper name because I didn't know if I would be able to continue to do so for all the bridges around Canary Wharf.

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Great Britain: West India Quay Footbridge (1)

A few months ago, we looked at bridges that cross the Thames River west of London. It's an idyllic area with pretty towns that have a rural feel.

The east side of London north of the Thames used to be filled with busy ports that are now closed. A lot of money went into converting this area into a financial center to rival London, but with mixed results due to the volatile economy during the past 20 years.

This area (called Canary Wharf) has a lot of pretty footbridges to carry people across the channels where ships loaded with goods used to travel. I think the developers must have encouraged the bridge engineers to be innovative in the design of these little bridges.

For instance, this pontoon bridge looks like it can be taken apart and reassembled wherever it might be needed. Each module is composed of two air-filled barrels with X-braced four-legged piers supporting a tubular superstructure and a rubber deck. The ends of the bridge are supported by the quay walls on each side of the channel. More information on this bridge can be obtained from the website that the designers (Anthony Hunt and Future Systems) created.

Canary Wharf is in the middle of the big downward bend in the Thames River shown in the Google Earth Photo above. We will look at some of the other bridges in this area over the next few days.

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Peru's Bridges: Puente a Machu Picchu (2)

Another view of the suspension bridge we studied yesterday. I was wondering if the longitudinal planks on the deck were made to carry vehicles or just to hold the deck to the floor beams. I'm not even sure if a vehicle could get through the legs of the towers (or if the bridge could support vehicles).

Lately I've been noticing the difference between the rather humble bridges in my blog and the more elegant structures presented by The Happy Pontist.

I think if we were novelists, he would be Thomas Mann whose elegant prose examined the world of educated people and their ideas. I would be more like John Steinbeck who discussed the ordinary people he met in his travels. The Tall Bridge Guy would represent the American idealism of Jack Kerouac and The Bridge Hunter would be a populist writer like Mark Twain.

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Peru's Bridges: Puente a Machu Picchu (1)

Another interesting pedestrian bridge across the Urubamba River on the way to the ruins of Machu Picchu. A pair of short reinforced concrete towers supports steel suspension cables that are anchored at the far sides of the bridge. Steel clamps are attached to the suspension cables and support suspender cables, floor beams, and the timber deck.

This bridge is similar to the inexpensive suspension bridges we saw by Walter Yanez in Ecuador. Perhaps its most interesting feature is the elaborate design of the fabric on the guard rails along the sides of the deck. The pattern appears to be an authentic design of the indigenous Peruvian culture.

The most distinguishing aspect of this area, which may not be obvious from these photos, is how steep and how green the mountain peaks are in this region. I've hiked extensively through the Sierras in California, but I don't recall ever seeing so many steep peaks crowded together as surround Machu Picchu.

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Peru's Bridges: Puente Aguas Calientes (3)

A last look at Puente Aguas Calientes with Anshel looking back from the bridge deck. This two-span pedestrian bridge couldn't be more different from the austere Incan structures in Cusco and at Machu Picchu.  Those structures are incredibly precise, I don't think I've ever seen stonework that fit together so well. The irrigation structures still function perfectly after hundreds of years of use.

This bridge on the other hand seems individual, personal, and arbitrary in its strange, arch-like bends, varying depth, and delightfully expressive handrail. It's as if the town of Aguas Caliente celebrates the somewhat sterile architecture of the Incas with more modest and personal architectural vision.

These more eclectic structures suggests that today a gentler society exists with greater individual freedoms than existed in the past.

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