Railway Structures
Cast Iron Columns
Many bridges supported on cast iron columns remain in use. These
columns are normally hollow, but may have been filled with concrete. This form
of construction was favoured for bridges over water, because columns could be
cast on land, floated out and sunk into the river bed.
The bridge carrying the Fareham line over the River Itchen at St Denys is a typical example of a plate girder bridge on cast iron columns. The diagonal cross-bracing between the columns is quite usual, especially in river structures. This restrains sideways movement in the columns.
Queen's Road bridge, Hastings is a fine example of a bridge supported on cast iron columns. In this case the columns are fluted and carry a wrought iron deck. The bridge, which is listed grade II was repaired and repainted in 1994. Stitch-weld repairs were required to the columns, which had been damaged by blockage of the drainage system.
Bridge Road bridge, Bursledon is supported on four cast iron columns. If a heavy road vehicle hit one of these it is possible that the column would collapse, leading to complete failure of the bridge. Very substantial concrete blocks guard against this happening.
Station Hill bridge, Ascot, is supported on no fewer than sixteen cast iron columns. The bridge is very wide in order to accommodate all of the tracks that were once necessary to allow operation of Royal Ascot race special trains.
Thurlow Park Road bridge, Tulse Hill is one of those most at risk of bridge strikes anywhere in Britain. This is because it spans an extremely busy road, the A205 South Circular Road, and is on a hill, which can make the headroom appear greater than it really is. Despite the garish paint scheme it is hit regularly. It is not just the bridge deck that has been struck. One of the cast iron columns has been replaced by a steel support. |
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This page was created 8 January 2010
