Wednesday 14th December – preparing Halley’s bridge for the move


Today I worked with a chippy and rigger to lift the timber panels on the bridge and tightening the cladding fixings and record the condition.
I created a document on the bridge loads so we could plan the lifting operations.  I also looked at the bridge plan bracing and tried to anticipate whether this would cope with the lift being eccentric due to rigging position.  We then spent the afternoon looking and discussing how the bridge could be supported and removed whilst maintaining the cladding in place.
Before anything can happen we need to remove the melt tanks below the bridge droppers, removal of the bridge dropper cladding and steel frame, and then filling in the depressions in the ground to form a stable surface onto which the bridge can be lowered.  The sequence then requires taking load but not raising the bridge more than 25mm, jacking the E2 module away (with the legs extended) against the deadweight of a couple of dozers, then in the space created sliding out the bridge bearing from the mouth of the E1 module, and then dropping down onto the prepared temporary ski frames.