Work to repair the footbridge at the station will begin on Monday, after engineers revealed the problem was “a lot worse than first envisaged”.
The bridge was closed to pedestrians on January 6, after staff from the SVR station notified police that the end of the footbridge, on the station side, “had lifted up significantly and appeared to be hanging dangerously in mid-air”.
Shropshire Council engineers have now carried out an investigation to discover the cause of the problem, believed to be the effects of cold weather and the long-term wear of people using it, and come up with a way to fix it.
However, the initial work will be a temporary repair, intended to be completed before February 19.
It will then remain open throughout the summer before contractors return for permanent repairs in late October, early November.
Gurnek Singh, Shropshire Council’s interim bridges and structures manager, said the problem had been hidden for many years despite inspections because of the design of the bridge.
He said: “The holding down bolt anchorages to the west end bearing supports have completely failed. The exact cause of failure is still largely unknown, and engineers have been looking at as-built records and will be undertaking further analysis work, modelling and calculations to try to determine the cause of the failure.
“The eight holding down bolts fix the deck walkway in position and prevent it from moving excessively under live pedestrian loading. However, engineers looking at the mode of failure believe the bolt failure has been caused by a combination of slat laden de-icing salts, which have penetrated onto the tops of the bank supports and ‘eaten’ away at the high tensile steel bolts; cyclic fatigue failure due to pedestrian live loading; and contraction of the main cables and lattice steelwork caused by the recent prolonged cold temperatures. Engineers also suspect the problem has been ongoing for a number of years, but has remained hidden from view during routine bridge inspections due to the design detailing.”
Over the coming months engineers will be working on the permanent solution to replace the holding down anchorage systems, and to tighten up the tension in the cables to the west tower, which have slackened following the failure of the holding down bolts.
Shropshire Council said that engineers will continue to monitor the footbridge on a regular basis to make sure it is safe until the permanent repairs are completed.
Steve Brown, the authority’s highways, transport and environmental maintenance manager, said: “Engineers from the council and its consultant WSP who have been assessing the damage and reviewing historical records, and have confirmed that it is a lot worse than first envisaged. Works to design a permanent repair will also be a lot more complex and therefore engineers have worked up a ‘quick-fix’ solution to enable the footbridge to be re-opened sooner to avoid major disruption to members of the public and tourist visiting the SVR.
“The footbridge is also a vital link between the SVR station and the surrounding facilities and businesses in the town centre. A permanent solution will be drawn up in the interim period, with works being planned for later in the year to avoid the peak tourism season.”