Months of traffic chaos in Derby will begin to tail away over the coming months as a new bow string arch bridge designed by HBPW begins to alleviate congestion in the East Midlands city.
The London Road over bridge on the south east side of the city centre carries the two lane A5194 over a total of seven railway lines and sidings, which form part of the Derby to Birmingham line.
However, when assessed, the ailing structure failed Network Rail’s BE4 liability for carrying two lanes of traffic, and an 18 tonne ‘buses only’ restriction was introduced until the problem could be solved.
Following design and build competitive tendering, contractors Morgan Sindall, working alongside Network Rail and the City Council, won the bid and invited HBPW to produce a bridge design to improve the situation and restore better traffic flow to Derby’s London Road area, which is close to the city’s main rail station.
“The existing over bridge is being demolished as part of the scheme,” said engineer James Cable, “with four existing spans being replaced by two new superstructures crossing a total of seven railway lines.
“Three of the spans will be replaced by a bow string arch bridge which, in turn, will see the removal of two supporting piers whilst creating a more open area beneath the new bridge. In addition the vertical alignment will also be altered to increase minimum vertical clearance from the railway to 4.78m in order to allow for future electrification of the lines.”
The scheme will also feature a traditional pre-cast concrete bridge deck across the remaining Bombardier span. The detailed design has been completed and work has now commenced on the sub structure for the span featuring the bow string arch bridge as well as the sub structure of the second span.