DAWSON-WAM were appointed by Kevin Watson Construction to carry out the installation of a secant piled basement, reinforced concrete capping beam, temporary propping, bulk excavation, load bearing piles and pile caps as part of a substantial residential development on the site of the Old Curzon Cinema on the Ormeau Road, Belfast. The development consisted of 54 luxury apartments with underground basement car parking.
The secant piled basement consisted of a hard-to-hard configuration of 720nr 450mm diameter concrete CFA piles with temporary steel casings and cage reinforcements to depths of up to 10m. The basement walls were temporarily supported by steel props and waling beams in isolated locations where the secant wall was adjacent to existing properties. The remainder of the basement was designed to cantilever during the 4m deep bulk excavation. The secant piled wall was installed as close as 100mm from adjacent properties with noise and vibration monitors in use throughout the piling installation. Through the use of one of DAWSON-WAM's fleet of eight double auger drive rigs the piles were installed with minimal noise and vibration resulting in no damage to any of the adjacent properties.
On completion of the 12,000m3 bulk excavation DAWSON-WAM constructed a temporary access ramp and mobilised the piling rig into the 4m deep basement. An additional 208nr 450mm diameter cased CFA load bearing piles were installed at depths of up to 14m together with piles caps.
The contract was completed on time within the 20 week programme period as well as to budget. The development was duly completed in late summer 2009.