Tag: river

Hungerford rail and footbridges, London

Hungerford rail and footbridges, London

The current bridge at Hungerford is formed of two elements: a trussed beam railway bridge on heavy brick supports completed in 1870, and either side of that, two lightweight Golden Jubilee footbridges. These were added in 2003 and are engineered to be attached to the original structure as well as supporting their own weight via a cable-stayed system. The bridge’s history and the cleverness of the engineers to produce something of such elegance and effectivness makes this my favourite bridge in London.

The hardest part about designed the new footbridges is that of course, they need to fit with what is already there. The steel cables and beams of the new bridges are attached to the solid foundations of the old rail rail bridge via a solid ring and carefully calculated pin joints – sketched above. I think it’s clear that the weight of the new bridges is almost negligible compared to the old – partly because pedestrians are much lighter and produce much less vibration than trains, but also signifying massive advancements in materials and engineering technology since the 19th century.

Bridge in Rouen, France

Bridge in Rouen, France

A road trip to Rouen, northern France a while ago led me to this engineering marvel over the Seine: Pont Gustave-Flaubert. It’s actually an opening bridge, which I didn’t even realise whilst I was there. I sketched it here from a photograph I took myself.

It’s a cable-stayed bridge, meaning its weight is carried to the support via cables that connect it to the concrete towers. In fact, the cables wrap around pulleys, which allow for some movement of the structure, but thereby reducing the chance of fracture.

The cables transfer the weight on the bridge on to the reinforced concrete towers and thereby into the ground, producing a structurally stable and reliable yet lightweight bridge.

From inspection I imagine the platforms to be semi-rigid – anchored to the ground but with a pontoon-type floating top element, although this assumption is not confirmed.