Introduction

The Aberdeen Harbour Expansion Project is one of Europe’s largest greenfield port capital investments projects over the next few decades . With a project investment of over £300 million, the project involves the construction of two new breakwaters each 600 m long, quay lengths of over 1.5 km, 2 million m3 of dredging including 0.25 million m3 of rock dredging, and about 1 million m3 of reclamation. The site is situated on the east coast of Scotland in a severe wave climate with design waves exceeding Hs~8m with single layer concrete armour units of up to 16 m3 required for the Southern Breakwater.

This paper sets out the development of the port masterplan and the key engineering design and environmental constraints, together utilising many of the principles set out in the forthcoming PIANC WG185 guide to the site selection and masterplanning of greenfield ports. The paper includes details of the background and context, the masterplanning process, numerical and physical wave modelling studies, and navigation simulation as well as the engineering and procurement process. Construction was fully under way in September 2017 and completion is scheduled for 2020.[PH1]

Background and context

Aberdeen Harbour has undergone substantial development over the last 40 years, primarily as a result of the growth in the oil and gas industry in the north-east of the UK. The growing trend for new, larger, multi-purpose vessels combined with the potential for new business streams including large cruise ships, the renewable energy sector, and decommissioning of oil and gas installations indicated that there is a case for growth beyond the capacity of the existing harbour infrastructure. Aberdeen Harbour Board therefore proceeded to develop a masterplan examining the case and direction for growth.

Masterplanning process

The masterplanning process is described in the paper using the same structure as the PIANC masterplanning guidelines, namely:

1. Establishing the ‘Needs and Vision’ and the ‘Performance and Functional’ requirements. This set out the initial vision and objectives of the new port at Aberdeen.
2. Establishing the ‘Spatial Needs’. Understanding the water and land areas and hinterland links.
3. Identifying and subsequently characterising three potential sites addressing issues such as:
   1. Marine: Bathymetry, geology, geotechnical, currents, sediments
   2. Terrestrial: Road and rail connections, material sources, utilities
   3. Environmental constraints: Legislative framework, Local planning issues, constraints and consultation. The chosen site included a Site of Special Scientific Interest (SSSI) and was adjacent to other designated sites.
4. Developing and screening the options based on multi-criteria analysis. This involved examining over 20 options in the three different sites.
5. Project Implementation:
   1. Undertaking
      • Numerical and physical wave modelling,
      • Navigation simulations and
      • Site surveys and ground investigations.
   2. Developing the:
      • Preliminary engineering and
      • Reference and Illustrative designs and associated specifications for tender purposes.
   3. Developing cost estimates, schedules and the procurement process.

The project implementation is described in more detail in the subsequent sections.

a) Modelling and simulation studies

The paper will describe the modelling and visualisation studies in detail:

1. Wave modelling for use in design and modelling of conditions from 50:1 to 1:200 year using MetOffice and ReMap data sets.
2. Flow modelling for use as input to the navigation simulation, sediment transport and environmental assessments.
3. Sediment transport assessments
4. Real time navigation simulation of the approach and berthing
5. 2D Physical modelling of the northern breakwater
6. 3D physical modelling of breakwater stability, wave disturbance in the harbour and vessel motions and line and fender loads
7. Visualisation: fly-through visualisation of the proposed works to enable the client and stakeholders to understand the nature and scope of the works being proposed.

b) Engineering design

The paper will describe the key engineering design features of:

1. The layout design including wave attenuation.
2. The breakwater design including examination of a number of options. The adopted Reference Design included 8m3, 10m3, 12m3 and 16m3 concrete armour units with crests at +12.6mCD and toes down to -11mCD. It included an unusual rear drainage trench to enable lowering of the crest structures.
3. Site surveys, review of historical information and extensive ground investigation.
4. The quay wall design, landside works: including paving, services and tie in to the existing local infrastructure.
5. The dredging design and associated revetments.

c) Environmental impact

The paper will describe the environmental impacts and mitigation measures.

d) Procurement strategy

Key to achieving best value for the marine construction was configuring the design to suit the operational constraints of the contractors’ plant and equipment, environmental constraints as well as material sourcing. It was seen that significant optimisation could be achieved if contractors were empowered to refine the design to suit their preferred methods of construction and hence the procurement strategy was configured to enable this goal. A Design & Build form of contract was adopted using the NEC3 form of Contract with a Reference Design forming the basis of the tender.

Key parts of the design package were:

• Detailed Reference design reports
• Design and performance requirements
• Construction and material requirements
• Drawing packages
• Environmental impact assessment
• Site information and ground investigation.