Ora Bridge: CFA, August 2019
Scope of Services:
Design and installation of bearing piles for abutments of a new highway bridge in Arua District, financed by the Uganda National Roads Authority (UNRA). A total number of 10 piles, each 600mm in diameter and 11m long were installed using a CFA rig within a week of mobilisation to site. All 10 piles were integrity tested using ultrasonic testing methods.
Location: Ora, Arua District, Uganda
Completion Date: August 2019
Main contractor: Terrain Services Ltd
Client: Uganda National Roads Authority (UNRA)
Project Description:
As part of UNRA’s prestigious programme of highway and bridge construction, EAP was once again selected as a preferred subcontractor to perform all piling works for Ora Bridge in Arua County, Northern Uganda. The main contractors for the project were Terrain Services Ltd., adding to EAP’s portfolio of successful contracts completed with the company.
EAP proposed installing the piles by the CFA method, which offers significant cost and time savings over traditional rotary bored piling techniques. The final offer came within the client’s budget and programme schedule.
In consultation with a specialist pile designer based in the UK, EAP undertook all piling design works for the project in order to achieve the most efficient solution. The piles were designed to withstand an axial load of 1200kN from the bridge’s superstructure and traffic loading.
The soils on site consisted of gradually stiffening clays going into intact rock. In order to achieve the required strength, all 10 No. piles were bored to practical refusal into the underlying bedrock.
The Soilmec CM50 CFA piling rig was mobilised to site from Kampala and succeeded in installing all 10 No. piles within a week of arriving on site, despite working within a remote and challenging environment.
EAP ensured the murram piling platform was adequate to perform the works in a timely and safe manner. Concrete was batched and delivered by a subcontractor commissioned by EAP. Reinforcement cages were cut and tied by EAP on site and subsequently installed in the CFA piles by vibration.
Following installation, EAP cut down the excess concrete to the required cut off level, exposing the reinforcement for tying into the pile cap. All the piles and tested for integrity using the TDR2 machine and the frequency response method.
