Engineers Australia

Advanced quality assurance for piling works for the Wicet Project in Gladstone

M. Larisch, N. Poskitt, H. Netterville and S. Dredge

Abstract

The “Wiggins Island Coal Export Terminal” (WICET) in Gladstone is one of the largest Greenfield port development projects in Queensland to date. The project will significantly increase the export capacity of the Gladstone Port making it one of the world’s largest coal export facilities. Stage 1 of the port development project commenced in 2011 with completion expected in 2014.

The piled foundations for the overhead gantry stacker and several of the yard conveyors were planned and executed in a design and construction contract by Abigroup Golding Joint Venture and Piling Contractors. WICET agreed to replace the original scheme of driven pre-cast concrete piles with a more efficient, economic and innovative CFA piling solution. This paper will briefly highlight the advantages of the alternative piling method comprising close to 700 CFA piles, approximately 25 m deep, most of them 900 mm in diameter.

The design and approval process included an in depth analysis of the pile group behaviour using numerous pile design software packages including finite element modelling for non-linear analysis.

Verification of conformance with horizontal and vertical design deflection criteria of the piles and pile caps for both ULS and SLS conditions was achieved by testing 3% of all working piles dynamically. Furthermore one vertical and one lateral static load test were carried out to verify the soil parameters used for the design of the deep foundations.

This paper describes the different load test procedures and their execution with respect to compliance with AS2159-2009. The authors will also highlight the advanced quality control systems adopted for the construction process of CFA piles.

The aim of this paper is to increase industry confidence in the use of CFA piles following a detailed review of the data collected during the design, testing and construction of these piles.