All-Ways Rigging Gear, Unanderra
Certification of 180 Tonne Lifting Beam for Snowy Hydro Limited
Westlake Punnett was engaged by All-Ways Rigging Gear in Unanderra to undertake structural assessment, testing and certification of a 180 Ton (182.88 Tonne) lifting beam in accordance with AS4991-2004.
The beam was designed primarily for the lifting of rotors for the Murray 1 Power Station, which is one of the 9 main power stations used for the Snowy Mountains Hydro Electricity Scheme. Fabrication of the lifting beam was conducted circa 1950’s and had been intermittently used throughout its life-span.
The scope of the project involved the inspection, material identification, non-destructive testing, detailed analysis and design checks in accordance with several relevant standards. As the beam was fabricated more than half a century ago, the materials used for the fabrication of steel and their mechanical properties varied significantly from those of today’s carbon steels. As such, research involving Australian and British Standards from the mid-to- late 1950’s along with material testing was required in order to accurately determine the mechanical characteristics of the beam.
Due to the non-standard geometry of the beam itself, Westlake Punnett & Associates Pty Ltd decided to approach the detailed analysis from two different angles – Quasi-Static analysis and Finite Element analysis. This allowed for thorough cross-referencing of results for both the Ultimate and Serviceability limit states required by modern day standards including AS4100-1998 as well as the Permissible Stress analysis required by AS3990-1993 and AS4991-2004.
The design check found that the beam did meet the modern standards providing any weld defects were rectified. Upon the rectification of defects noted through non-destructive ultrasonic, magnetic particle and bearing blue testing by Bureau Veritas and Lavis Engineering respectively, the beam was certified as structurally adequate to withstand its in-service load demands.