Boom collapse during pile extraction highlights FPS Guidance
It has been reported that a mobile crane has failed during construction of a £40 million supermarket scheme for Tesco on the former site of Rotherham Borough Council’s civic buildings in Rotherham. Eyewitnesses reported a “loud bang” as the boom failed.
The Construction Enquirer reports that the 80t all-terrain Demag crane was involved in pile extraction when a sudden shock load is understood to have caused the boom to recoil and bend at a right angle.
Emsley Crane Hire are said to own the 80t Demag, which had been called in to “lift the steel piles at ISG’s job”.
Director John Emsley told Construction Enquier that the retractable boom sequence had been set in the right configuration, but the boom had received a shock load during the pile extraction.
“The crane driver realised there was a problem and reacted immediately by slewing round to a safe area to rest the jib. Our company have immediately stopped this crane operation.
Unfortunately our crane was retracting piles with a pile extraction hammer under a CPA hire. Our crane was given a shock load from the hammer causing the jib failure.”
Federation of Piling Specialists Guidance
Extraction of temporary casings and temporary works piles is common within civil engineering and the piling industry. The Federation of Piling Specialists has published Notes for Guidance on the extraction of temporary casings and temporary piles within the piling industry.
FPS state that the document:
“considers the removal of temporary casings and temporary piles which is a common requirement of the industry and is an operation which may generate significant forces which are difficult to quantify.
The extraction process may require the use of rigs, cranes, purpose-built extractors, jacking systems or other means but whatever the system employed an assessment needs to be made of the specific operation being undertaken. The variables which contribute to the force required to extract a particular element are many, varied and difficult to calculate and are not only limited to the soils applying friction to the outside of the casing or pile.
To date, in most cases, assessments have been made on the basis of experience, however, following recent occurrences within the industry, the Safety and Training Committee, together with the HSE., identified that a more rigorous procedure was required and that a set of guidelines which outlined the various factors which need to be considered would be a useful tool, hence this document.”