- The first of its kind in South East Asia.
- Arup designed a purpose-built dry dock to accommodate construction.
- Installed in 43m of water, a 13,000t top structure addded later.
Arup engineered, procured, constructed and installed the Malampaya Congrete Gravity Substructure (CGS) as part of a consortium with John Holland Group and Van Oord.
The firm was involved from the project outset, conducting initial feasibility studies and a Front End Engineering Design study in 1998.
The project involved many technical and organisational challenges, calling for a wide range of skills. Studies were performed for floating stability, vessel sea-tow response, installation ballasting sequence and post-installation wave and seismic performance.
Arup designed a purpose-built dry dock to ensure a safe working environment during the two-year construction period. Due to high seismic activity in the Philippines, likely ground movement was the principal design issue.
Detailed analyses were conducted for the dry dock, including a seismic hazard assessment, site response studies, liquefaction assessments and slope stability analysis.
Analysis of ground conditions
Analyses of soil conditions highlighted that certain layers were potentially susceptible to liquefaction – a phenomenon where soil loses strength and stiffness under stress. A comprehensive dewatering scheme was installed, with vacuum-assisted deep wells and an array of additional well points.
The consortium organised workshops to facilitate good relationships between team members and clients, and with local communities and workers.
The project was delivered within budget and ahead of schedule, and was awarded an Australia Concrete Institute award in 2001.