Load Bearing PilesBored Pile WallsLoad & Integrity TestingGround InvestigationDesign

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EAST

AFRICAN

PILING

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EAST

AFRICAN

PILING

The CompanyEast African Piling Ltd is a specialist piling contractor working out of Uganda and serving the wider region. With six decades experience of construction in East Africa and over 20 years of geotechnical design the team is focused solely on providing piled solutions and offers a turnkey service from ground investigation, design and installation through to load and integrity testing.

Cast Insitu Bored PilesWith our fully computerised Soilmec CM50 rig we can offer piles up to 900mm in diameter and 25m in depth using the Continous Flight Auger (CFA) method.

CFA piles are formed by drilling to the required depth using a hollow stem continuous flight auger. Af-ter reaching the designed depth, a high slump concrete is then pumped through the hollow stem. While the concrete is being pumped, the au-ger is withdrawn at a controlled rate, removing the soil and forming a shaft of fluid concrete extending to ground level. A reinforcing cage is then inserted into the fluid con-crete. The construction sequence is shown in the diagram to the right.

A computer, positioned in the cab directly in front of the operator, continuously displays the bor-ing and concreting parameters. During the drilling phase, the depth of the auger, speed of ro-tation and penetration rate are displayed. Subsequently, during the concreting phase a con-tinuous record of concrete pressure and rate of pumping is shown; the display is presented in a manner that highlights under-supply and over-supply of concrete, compared with the target value. On completion of a pile, a computer printout can be generated for viewing. The full data of pile construction details are stored in a data logger module, which is returned at regular in-tervals to our Head Office. The data is then analysed as a further check on the integrity of each pile.

Bored Pile WallsBored pile walls can be the ideal solution for basements, underground carparks and slope stabilisation where deep retaining walls are required or space is restricted. The most common methods, Secant and Contiguous are discussed on this page, hovever further guidence and explanations of different techniques can be found in CIRIA guide C580.

Secant WallsSecant piles are installed by overlapping reinforced male piles and female piles which are made from a low strength gain concrete. They are adopted to restrict groundwater and fines inflow with re-tained heights of up to 8m common. Se-cant piling offers minimal vibration, low noise levels and the flexibility to fit com-plex site boundaries to maximise land use. While at the same time, avoiding any risk of construction induced settlements to neighbouring structures.

Contiguous Wall Layout

Secant Wall Layout

Contiguous WallsContrary to their name, contiguous piles are actually installed with a gap of 100-200mm per pile. This means that the wall is not water or fines tight. However where the conditions allow, such as in cohesive soils, it can be the most eco-nomic form of retaining wall.

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EAST

AFRICAN

PILING

Load TestingLoad tests are used to either prove the maximum capacity of piles or verify predicted design values and settle-ment under pressure. Where the ultimate load is to be determined the test should be conducted on a pile that is expendable to the main works. A working pile may be used as a test pile but the maximum test load should not generally exceed 1.5 x the safe working load.

Test piles are normally adopted where, for commercial reasons, a factor of safety of less than 3 using a British Standard (BS8004) design approach or 2 using a Eurocode (EC7) design approach has been adopted. Where a factor of safety of 2.5 (BS8004) or 1.7 (EC7) is used working pile load tests are usually needed. Lower factors of safety will necessitate expendable pile load tests, however all approaches should be discussed and agreed with the relevant authorities.

Integrity Testing Integrity testing is carried out in order to identify anomalies in piles that could be of a structural importance. There are a variety of testing procedures available including the ‘impulse response’ and ‘sonic echo’ methods. They work by sending a stress wave down the pile after it has been struck by an impact device. The reflection, when ana-lysed in conjunction with the knowledge of the soil conditions and pile dimensions, provides information on the structural quality.

ContactEast African Piling Ltd.Plot 93 Lubowa,Entebbe Rd. PO Box 23132, Kampala Email: info@eapiling.comUganda Tel: +256 (0)414200119