Thursday, 13 August 2015

The End is Nigh

After nearly 20 months of working on Hammersmith Flyover in West London, it only remains to tidy up and leave the bridge "as we found it". Although, hopefully in a better state than it was in 2012 when it was in danger of collapse following years of neglect and had to be closed to traffic!

Today, the flyover has 34 new sliding bearings beneath its piers, over 150 km of steel cables holding it together (the distance from London to Calais - rather apt given that they were installed by Freyssinet, a French company) and a new waterproofed road surface.

Access to the bearings has been improved to allow future inspections to take place and five new door openings have been cut into some of the piers for access into the bridge deck above.

New door opening (without door)
One of the final tasks is to re-instate the covering over the pits surrounding the piers.  These were removed to enable access to the old and rusting bearings upon which the piers sat.

Threaded couplers were cast into the pit wall during their strengthening.  Following a detailed survey of these, bespoke seating cleats were made so that the bolt holes exactly matched the coupler locations.

One of four seating cleats per pit
Next, galvanised (rust proof) steel beams are installed around each pier and a shelf angle is attached to the pier itself.

Steel beams installed
The pit is then covered with a frame and pre-fabricated trench panels - provided by Fibrelite.

Panel installation
The final steps are to replace the tarmac and paving slabs around the piers to blend into the covers. At the pier, another overlapping cover will be fixed to the pier to allow it to move freely.

[to be continued]

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