Twed Heights: Rotary Piles, June 2018
Scope of Services:
Installation of 121no. 800mm rotary piles 278no. 600mm rotary piles.
Integrity testing on at least 50% of the piles.
Location: Lourdel Rd, Nakasero Kampala
Completion Date: June 2018
Main contractor: Twed Property Development
Client: Twed Property Development
Project Description:
EAP mobilised a Soilmec R620 rotary piling rig to install the piles at the site in central Kampala. The project is a mixed use development. The main contractor had excavated down to the basement level and required piles to found the building on the underlying rock.
Challenges came from the difficult access in the excavated area, which had very little space around, tight corners and a steep ramp. This caused problems not only for getting the piling equipment onto the site but also the delivery of concrete to the pile locations since the ramp was difficult to drive on when wet.
The piles were drilled to practical refusal in the rock which was found between a few metres and 20m under the surface. The rig was equipped with a 4 section telescopic interlocking Kelly bar capable of drilling to over 40m. EAP mobilised augers with rock bits for 800mm and 600mm diameter piles in order to penetrate into the rock and cleaning buckets to clear as much loose material as possible from the base of the pile.
Steel cages were fabricated on the site by another contractor were loaded into the open bore by EAP using an all-terrain crane.
Concrete was batched on site by the client. EAP used an 8inch tremie pipe system to install the concrete. The concrete was filled from concrete mixer trucks directly into the tremie hopper.
The pipes were lifted into position using the all-terrain crane. The site suffered from poor drainage and the surface was not solid after rain so EAP mobilised an all-terrain concrete mixer to assist in the delivery of the concrete.
Approximately 50% of the piles were subject to integrity testing using the frequency response method. The data was taken using TDR2 machine and analysed jointly between EAP and ND Technology of Southampton, in UK, experts in the analysis of pile integrity test data.
