BEDFORD SQUARE

belfast

The largest building to be underpinned in Ireland.

A listed building over four floors, of solid masonry and sandstone column construction it certainly was challenging. With wall and column loadings being provided by the contractor’s engineer, we designed and constructed a full underpinning scheme whilst working in tandem with CFA piles being installed for a new adjoining basement.

Provision of a low vibration system was key as settlement was due to the erosion of the original timber piles and ground beams.  To overcome this, we provided drilled and cased mini piles working to vibration levels less than 5mm / sec.

Piles were installed within 450mm of existing walls and columns using our D500 piling and mini CFA rigs. Due to the restricted access and limited openings for air transfer we used our 3 phase electric power packs which meant no fume extraction was required. This provided an excellent working environment for all trades and one less cost for the main contractor.

The piles were incorporated within our internal piled raft underpinning system where structural steel needles were placed in diamond cored holes, attached to piles and encompassed within a 450mm deep reinforced concrete structural floor slab.

This challenging project was completed within programme and budget helped enormously by good contractor / sub-contractor communication and team work.

PROJECT SPECIFICATION

364 drilled and cased piles totalling more than 3500L/M – that’s over 2 miles of piles.

Over 300 diamond cores up to 400mm dia between 600mm and 3.0m long.

Over 450 cubic meters of concrete.

Almost 100T of reinforcement and structural steel.