14 November 2013

Teesside Bridges: 2. Newport Lift Bridge

Like its neighbouring transporter bridge, the Tees Newport Lift Bridge is both an industrial relic and an icon for the area. The Transporter Bridge had been opened in 1911, and as with all bridges of its type it gave priority to shipping - in its "rest" state vessels can pass but vehicles cannot, and when in motion only a very limited number of vehicles can be carried at one time in one direction.

The lift bridge offered a considerable improvement for road users, giving priority to them insofar as traffic could cross while the bridge was at rest. It opened in 1934, built by Dorman Long to a design by Mott, Hay and Anderson, becoming at that time the first significant vertical lift bridge in Britain, and one of the largest in the world (at 82m, its main span was some way longer, for example, than Rotterdam's De Hef, built in 1927 and spanning 52m, which I also visited recently).

As traffic grew, even less frequent lifts of the bridge could lead to considerable disruption. The bridge lifted for the last time on 18 November 1990, remaining in its "down" position ever since.

On a dull rainy day, the bridge was impressive but also somewhat lumpen. The massive lift towers have a considerable presence but the bridge did not appear elegant. However, there are some nice photos online of the bridge at night (taken from both ground level and from tower top), which show how attractive it can appear.

It's remarkable how much of the bridge has been left intact. It's easy to imagine that most of the steelwork is redundant, and due to its complexity, prone to corrosion and expensive to paint. However, it's not just the towers that remain in place, but the control cabin at midspan, and most of the lifting machinery including cables, sheaves and counterweights.

I guess that perhaps the main span is still largely supported on its counterweights, with only a small dead load reaction and all the live load reaction carried down through the span-end bearings. That will certainly have been the arrangement during its working lifetime, and it may have been too expensive to change it when the bridge ceased operating.

Further information:


Anonymous said...

Question--does making the top of the truss curved like that make it stronger, or is that just to please someone's esthetic sense [not mine]? I loves me some vertical lifts--especially when they are still active, and all straight lines--like a couple or 3 here in the Pac. NW.

Anonymous said...

whilst on the subject of opening bridges, were you intending to cover the recent competition for a replacement bridge in Gothenburg, Sweden :



The Happy Pontist said...

Re: the curved truss, think of the bridge span as like a plank of wood. If you load it up, it will always break in the middle. So: the curve is to make the truss deeper, and hence stronger, in the middle.

The Happy Pontist said...

Re: the Hisingsbron contest, I will see if I can get time to cover it, although I'm likely to struggle to get to it.