POLYSTYRENE FILL is likely to be retained in a key bridge structure on the Channel Tunnel Rail Link which was damaged by fire in February.
Work remains halted at Brewers Road on the Alfred McAlpine/Amec joint venture Contract 330 after the fire ripped through the structure (Ground Engineering March 2001).
It began when polystyrene fill in a road embankment between a roof slab over the CTRL and a road slab mysteriously ignited, badly burning the road slab and surface as well as parts of contiguous piles supporting the sides of the void and rail cutting.
Designer Rail Link Engineering is finalising plans which are understood to be based on repair rather than demolition. Repair would involve waterjetting burned concrete in the road deck, replacing damaged steelwork and making good the slab.
Analysis of the structure is understood to have concluded that the piles and the lower roof slab are undamaged.
RLE engineers are also believed to have recommended that polystyrene fill be retained in the structure and associated embankments covered with 700mm topsoil.
Designers are understood to believe the risk of the embankment catching fire during a traffic accident is mitigated by the topsoil and bridge crash barriers.
Approval is required from Kent County Council and client London & Continental before a final decision is made, but work is expected to finish by mid-June.