Great Britain: Midland Road Bridge (2)

Returning to Bath on the footpath along the River Avon, we get an interesting view of the underside of the Midland Road Bridge. We can see the bottom chord of the truss supporting the floor beams that hold up the deck. You can also see the thousands of rivets used to build the floor beams and the bottom chords.

The underside of the bridge is surprisingly clean with just a few rust spots on the soffit. Since the bridge was most probably built before WWII, I would guess it has been rehabilitated.

I found an article on the internet (by someone with the poetic name of Pierre Terre), who said the Midland Road Bridge had been moved from its original location at the Bath Green Park Railway Station. Most likely the bridge was cleaned during the move. Note the use of soldier piles for a quay wall under the bridge. Perhaps the river was wider at it's former location because you can't even see the north bridge abutment behind the heavy shrubbery.

Unlike the underside of many bridges, the underside of this bridge clearly shows how the load is carried.  The beefy, bottom chords not only acts in tension, but they also carrying the floor beams through shear and moment. I like how the floor beams are haunched to better carry the positive moment (and to allow room for the chords). I wonder if the bridge was used to carry trains at its former location?

Great Britain: Midland Road 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.