Great Britain: Victoria Bridge (2)

Another view of the Victoria Bridge in Bath. The Happy Pontist pointed out that this bridge was designed by James Dredge, a local brewer who had some interesting ideas about structural mechanics. He patented his 'taper principle' that took into account that the load in the suspension chain was smallest at midspan and largest at the towers. He made use of this idea on the Victoria Bridge by designing a suspension chain with 12 links at the ends and only 5 links at mid-span.

He designed 50 bridges, but only the Victoria Bridge and the Stowell Park Bridge remain. In fact, the Victoria Bridge is sometimes damaged by vandals because it is in a secluded area. Work was recently completed to make the site part of a parkway that is more frequented by people in the hope that this will protect the bridge.

It is hard to imagine that Victoria Bridge ever carried much traffic. For one thing, the opening in the tower is only large enough to admit a single vehicle. R.A. Griffith's analysis shows that the current pedestrian load is about half the original vehicular load for this bridge.  Griffith also mentioned that Dredge may have gone into the bridge business so he could transport his beer into neighboring communities. However, another Dredge Bridge, the Ballievy Bridge in Ireland, was destroyed when a 27 ton lorry drove onto it in 1988, suggesting that these bridges were not designed for heavy loads.

Victoria Bridge has a span length of 45.7 m (150 ft), a deck width of 5.8 m (19 ft), a tower height of 6.4 m (21 ft), and a chain sag of 6.6 m (22 ft). We'll take a last look at this interesting bridge tomorrow.

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

Great Britain: Victoria Bridge at Bath

A 19th century wrought iron suspension bridge across the River Avon. The bridge was built in 1836 with iron chains instead of steel cables, which wouldn't be in use for another thirty years. The iron chains were draped over a pair of squat, stone towers. Each chain has a pair of sloping hangers supporting the deck. The slope of the hangers becomes more oblique towards the center of the bridge and puts longitudinal elements of the deck into compression. Each hanger is attached to a steel floor beam which carries the timber deck and iron railing.

An interesting article by RA Griffiths was written about this bridge.  The author discusses the designer, the design, the bridge's history, and recent improvements to the bridge and it's site. A structural analysis of the bridge is also provided. We'll take another look at this interesting bridge tomorrow.

Great Britain: Victoria Bridge at Bath by Mark Yashinsky is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.

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.