Pile Assemblies

Pile Drive Housing Cap Investigation and Re-Design

Over the last few months API Engineering has been assisting Thurton Foundries in the investigation of failures occurring in pile assemblies.

Design Issue

Piling involves the installation of structural elements to transfer foundation loads through weak soils to stronger underlying ground. Piles are driven into the ground using a large hydraulic hammer called a pile driver.  The forces experienced by the pile can be extremely high, depending on various factors, including the soil density.

The customer offers a wide range of piling and retention systems, but recently they found that cracks in the welding made between the pile tube and housing were developing. These cracks continued to occur after 6-10 months of operation. Design changes were made, but the cracking developed into a chronic design failure.

On-site Failure Investigation

In order to understand the type of failure which was occurring API Engineering carried out a series of on-site inspections during which data and photos were collected. From these the root cause of failure was identified.

Design Modification

A new pile drive housing cap was designed with a modified load path to avoid overloading the welding during hammering of the pile. FEA analysis and welding strength calculations were used to ascertain the real world stress patterns and increased design life.

Component and assembly drawings were developed and passed to Thurton Foundries for the production of the new design.