27 July 2017

Yorkshire Bridges: 14. Blonk Bridge, Sheffield

The next bridge upstream from Smithfield Bridge is Blonk Bridge, which carries Blonk Street across the River Don.

This is a three-span masonry arch bridge, completed in 1828 by Doncaster-based architects Woodhead and Hurst, the contractor being a Mr Birchett. It cost £250 to build.

The spans are elliptical in shape, or possibly three-centered. The masonry looks well detailed, with the facing voussoirs tying into the main spandrel stone courses, although the geometry is such that the spandrel courses are all of a different height.

The masonry above the stringcourse seems to be of a different type and construction, perhaps associated with bridge alterations undertaken in 1913 (I can't find any details of what was altered online).

The most attractive feature on the bridge is its downstream parapet, which is a decorative cast iron balustrade. It looks pleasant from the outside, and is very nicely painted on the inner face. The casting is "one-sided" which looks decidedly odd from close at hand.

The upstream parapet is in reinforced concrete, and quite out of character with the rest of the structure. There were plans to replace this with a metal parapet back in 2007, but evidently nothing came of it.

The bridge was Listed Grade II in the early 1970s.

Further information:


stone cutting said...

Some interesting design choices there. Why make the expressed arch so thin at the crown? Even with the current thickness there is room for some fiddling with geometry to even up the beds in the spandrel.

The iron parapet is a later addition for sure. Original road level likely to be at the bottom of that string course.

Note the sag in the arch, made up to get the string course true.

I wonder what is leaking to produce that heavy looking water flow about 1m in on both spans?

Barry said...

I made the cast iron bridge moulds in the 90's, at Thomas Clarke & Sons foundry Sheffield.