Difference between revisions of "Arpley Bridge, Warrington"
| Line 1: | Line 1: | ||
[[Image:Geograph-4363473-by-Matt-Harrop.jpg|thumb|The Mersey breaches its wall at Bridgefoot | |||
cc-by-sa/2.0 - © Matt Harrop - geograph.org.uk/p/4363473]] | |||
This is a 180 ft span girder bridge across the River Mersey in Warrington. It is of particular interest because it retains an unusual design of wrought iron box girder from the early 1850s. | This is a 180 ft span girder bridge across the River Mersey in Warrington. It is of particular interest because it retains an unusual design of wrought iron box girder from the early 1850s. | ||
| Line 5: | Line 7: | ||
By 1908 the bridge was no longer suitable for the weight of locomotives needing to use it, and it was decided to strengthen it, and also to widen it to current loading gauge standards. This had to be done while maintaining traffic on the railway. The work was the responsibility of [[William Dawson (1860- )|William Dawson]], who presented a Paper on the subject to the I.C.E. in 1911.<ref>Institutuion of Civil Engineers, CLXXXIV, Session 1910-11, Part II</ref>. Dawson had been responsible for strengthening the Conway railway bridge in 1899. The Paper also describes the design of the original bridge. There were three large wrought iron plate girders, 190 ft long between bearing centres, with a camber of 9". The central girder was of the box type, 16 ft 9" high. The outer girders were of the single plate web type, 13 ft high. Walkways were provided outboard of the outer girders, supported on wrought iron cantilevered brackets. The railway lines were carried on 9" x 9" timber beams, spanning the full width over the girders and bolted to the bottom of the girders. | By 1908 the bridge was no longer suitable for the weight of locomotives needing to use it, and it was decided to strengthen it, and also to widen it to current loading gauge standards. This had to be done while maintaining traffic on the railway. The work was the responsibility of [[William Dawson (1860- )|William Dawson]], who presented a Paper on the subject to the I.C.E. in 1911.<ref>Institutuion of Civil Engineers, CLXXXIV, Session 1910-11, Part II</ref>. Dawson had been responsible for strengthening the Conway railway bridge in 1899. The Paper also describes the design of the original bridge. There were three large wrought iron plate girders, 190 ft long between bearing centres, with a camber of 9". The central girder was of the box type, 16 ft 9" high. The outer girders were of the single plate web type, 13 ft high. Walkways were provided outboard of the outer girders, supported on wrought iron cantilevered brackets. The railway lines were carried on 9" x 9" timber beams, spanning the full width over the girders and bolted to the bottom of the girders. | ||
An interesting feature was the use of iron castings riveted to the top flange to accommodate compression loading. The castings were of semi-circular section with horizontal flanges for bolting to the wrought iron top flanges, each 8 ft long, with a wall thickness of 2.25". The castings had vertical flanges at each end, allowing them to be riveted or bolted together. The castings are visible on top of the flanges in the high resolution photograph [https://www.geograph.org.uk/more.php?id=4363473 here]. | An interesting feature was the use of iron castings riveted to the top flange to accommodate compression loading. The castings were of semi-circular section with horizontal flanges for bolting to the wrought iron top flanges, each 8 ft long, with a wall thickness of 2.25". The castings had vertical flanges at each end, allowing them to be riveted or bolted together. The castings are visible on top of the flanges in the high resolution photograph [https://www.geograph.org.uk/more.php?id=4363473 here]. See above for lower resolution version. | ||
The two outer wrought iron girders were replaced by steel trusses of the Linville type. The original central box girder was retained, but its loading was partly transferred to the two outer girders by means of overhead lattice girders, in order to reduce the stresses in the bottom flange. This [https://www.flickr.com/photos/shaunsgrimepics/38365893292/ high resolution photo] shows the arrangement of the girders. The iron castings on the top of the central box girder are visible. | The two outer wrought iron girders were replaced by steel trusses of the Linville type. The original central box girder was retained, but its loading was partly transferred to the two outer girders by means of overhead lattice girders, in order to reduce the stresses in the bottom flange. This [https://www.flickr.com/photos/shaunsgrimepics/38365893292/ high resolution photo] shows the arrangement of the girders. The iron castings on the top of the central box girder are visible. | ||
Revision as of 15:16, 6 June 2020
This is a 180 ft span girder bridge across the River Mersey in Warrington. It is of particular interest because it retains an unusual design of wrought iron box girder from the early 1850s.
It was erected in 1853-4 for the Warrington and Stockport Railway.[1]. The designer was John Lister, and the ironwork was constructed by the nearby Bank Quay Foundry Co. The W&SR was later absorbed by the London North-Western Railway.
By 1908 the bridge was no longer suitable for the weight of locomotives needing to use it, and it was decided to strengthen it, and also to widen it to current loading gauge standards. This had to be done while maintaining traffic on the railway. The work was the responsibility of William Dawson, who presented a Paper on the subject to the I.C.E. in 1911.[2]. Dawson had been responsible for strengthening the Conway railway bridge in 1899. The Paper also describes the design of the original bridge. There were three large wrought iron plate girders, 190 ft long between bearing centres, with a camber of 9". The central girder was of the box type, 16 ft 9" high. The outer girders were of the single plate web type, 13 ft high. Walkways were provided outboard of the outer girders, supported on wrought iron cantilevered brackets. The railway lines were carried on 9" x 9" timber beams, spanning the full width over the girders and bolted to the bottom of the girders.
An interesting feature was the use of iron castings riveted to the top flange to accommodate compression loading. The castings were of semi-circular section with horizontal flanges for bolting to the wrought iron top flanges, each 8 ft long, with a wall thickness of 2.25". The castings had vertical flanges at each end, allowing them to be riveted or bolted together. The castings are visible on top of the flanges in the high resolution photograph here. See above for lower resolution version.
The two outer wrought iron girders were replaced by steel trusses of the Linville type. The original central box girder was retained, but its loading was partly transferred to the two outer girders by means of overhead lattice girders, in order to reduce the stresses in the bottom flange. This high resolution photo shows the arrangement of the girders. The iron castings on the top of the central box girder are visible.
Another Geograph photo and map here.
For information about the location, and history of the railway in the vicinity of the bridge, see here and here.