POLYSTYRENE FILL is likely to be retained in a key bridge structure on the Channel Tunnel Rail Link which was damaged by fire last month.
Work remains halted at Brewers Road on the Alfred McAlpine/Amec joint venture Contract 330 this week, six weeks after the fill fireball.
A night time fire ripped through the structure when polystyrene fill, forming a road embankment and contained in a void between a roof slab over the CTRL and a road slab, mysteriously caught fire (NCE 22 February).
The road slab and surface were badly burned along with parts of contiguous piles supporting the sides of the void and rail cutting.
Designer Rail Link Engineering (RLE) 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 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 that the risk of the embankment catching fire during a traffic accident will be mitigated by the topsoil and bridge crash barriers.
Approval is required from Kent County Council and client London & Continental Railways before a final decision is made, but the work is expected to finish by mid-June.