McDowall Affleck was appointed by EPC Contractor, NuEnergy, to provide structural engineering services for the Junction Road Gas Power Station in New Plymouth (NZ) for their end client Todd Energy. The plant consists of a 120 MW Open Cycle Gas Turbine Power Station using two GE LM6000 Gas Turbines and associated balance of plant. McDowall Affleck and Italian partner Studio Techne’ coordinated the geotechnical investigation and provided an optimised design for the two GE LM6000 Gas turbines, based on an advanced dynamic analysis which considered the soil-structure interaction.
We were to provide the coordination of the geotechnical investigation and design optimisation of LM6000 gas turbine foundations and design of foundations for balance of plant.
We were faced with a few challenges; the preliminary design of LM6000 foundation by others significantly exceeded budget and the fast track program required staged delivery. We had inadequate input from the equipment supplier requiring several iterations and inadequate geotechnical input for dynamic analysis which required additional investigation.
We worked closely with NuEnergy to obtain required data to commence design (geotechnical parameters and input from equipment manufacturers) and initial preliminary analysis of the LM6000 foundations based on optimised dimensions as per previous designs was overcome. Our comprehensive dynamic analysis including soil structure interaction allowed optimising the foundation.
Concrete volume of optimised foundations for both LM6000 gas turbines is approximately 300 cubic metres less than the initial design by others.