Project Onslow, Australia


Innovation over open water

Marine works by BESIX and its partner Thiess were designed, procured and constructed for Chevron in the form of 2 quays and a breakwater to facilitate transport and protect the operation’s harbour from storms and heavy seas.

Risky requirements, remote location

The market for marine works is dynamic and demanding, requiring ad hoc, innovative solutions and involving a high level of risk. Onslow in Western Australia is prone to tropical storms, high seas and unpredictable weather, making marine protection critical to transport in the area – especially for global energy company Chevron, which operates a facility along the nearby coast. Chevron had to find design and construction subcontractors that are capable of meeting greater-than-usual market demands.

Challenging environment

BESIX and Thiess were chosen as joint subcontractors by Chevron Australia to design, source and construct a series of marine works in a remote location, often over open water and under dicey environmental conditions. The design of the works also incorporated construction elements that have never been applied to offshore structures.

Our ability to work proactively with the client to find design solutions along with our safety culture, high performance and reliability have made us one of the most trusted subcontractors on site.

Fabian Boucher
Operations Manager, BESIX

Slow and steady for the win

Taking a slow and steady approach characterised by an extreme focus on safety-in-design, BESIX was able to complete the project 3 months ahead of schedule with zero safety or environmental incidents. Chevron’s new offloading facility consisting of two quays and a 1-km breakwater made of rock and concrete designed to last a half century, even in the face of storm surges, extreme waves and seismic activity. The BESIX team relied on its expertise in creative solutions to combine offshore stone columns with partial soil replacement to keep costs down.

Project details

Project name



Quay Walls, Breakwaters

Contract type

Design & Build


Onslow, Australia




Chevron, USA and Bechtel

Building Period

2011 - 2015



Total value

€ 250 million

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