28 July 2014

Yorkshire Bridges: 4. Needle Eye Bridge

Okay, I'll continue this series of posts a little further north along the M1 Motorway. I'm bypassing the Cock Inn Bridge simply because it proved impossible to get a decent photograph, which means the next bridge of interest is the Needle Eye Bridge.

This is a three-pin concrete arch "accommodation bridge", built to carry farm traffic and pedestrians. The arch spans 88m between springings, and was cast entirely in-situ in reinforced concrete.

It seems to owe more than a little to Robert Maillart's 1933 Felsegg Bridge, the first of the Swiss designer's concrete arch bridges to adopt an angle at the upper hinge rather than a continuous curve. This is a departure from pre-conceived notions of what an arch should look like, and is structurally more rational, responding appropriately to the full envelope of possible live load effects. Needle Eye Bridge lacks the sharp angle at the crown of the arch, but overall the bridge is shaped in a similar manner.

It is better than Maillart's bridge, however, in its use of prestressed suspended side spans, preserving a simple, clear geometry. Maillart's designs paired the solid main span with finicky, slender approach structures, often over-fussy in their detailing.

My sense is of a design team very aware of precedent, and enjoying the rare opportunity to experiment with form.

As with the other two M1 bridges I featured recently, at Droppingwell and Smithy Wood, I find it amazing that this bridge is not protected by any kind of heritage status. Sure, it only dates to the 1960s, but the whole set of bridges along this part of the motorway, designed by the West Riding County Council, is remarkable and worthy of wide recognition.

Further information:


Imre Laufer said...

It's interesting to see how the bridge faces react to the climate. One side (with the graffiti) has a rather clean surface, but there are runoff stains on the other face - even though the drip edges are missing on both sides.

James Clark said...

There is a very similar bridge to this near J7 of the M621 (which originally was the northernmost section of the M1 I believe). In great condition and very elegant!