Design method for the ‘impression pile’

Urban development in congested cities requires a better exploitation of the available surface, leading to taller structures. These buildings are usually founded on piles that have be increased dimension accommodate larger loads, resulting increases both cost and carbon dioxide footprint pile foundation. An alternative option is improve performance by enhancing shaft capacity, which commonly most important factor determining ultimate capacity constructed clay soil subjected axial load. For stiff clays such as London Clay, soil–pile friction may profiling side walls bored cast situ with small discrete ‘impressions’ latter form nodules concreted pile. Centrifuge tests carried out at City, University London, field trials undertaken Keltbray Piling across different sites showed an increase around 40%. In this work, simple design method based experimental evidence existing plastic failure mechanism was derived for ‘impression’ piles. The proposed shows good agreement data enables direct prediction future designs.