In order to allow for container vessels of up to 2,400TEU, the existing quay at Alexandra Quay East (AQE) needed to be deepened to a declared depth of -11mCD. The existing quay structure was made up of large concrete caissons with a shallower foundation than the future dredge depth. This posed a real challenge to the deepening plan.
In order to design a new quay wall and crane beam solution, a detailed understanding of the stability and condition of the caissons was required. The caisson founding soils and backfill material were of particular interest. In order to assess if the caissons could be used as part of the new structure, Arup also designed, procured and managed a unique structural inspection approach which used the latest Multibeam Echo Sounder technology (MBES) with supplementary dive inspections. This provided a comprehensive structural assessment of the underwater features. The DTM was used to highlight structural features, defects and scour to a resolution of 5cm. Arup undertook a detailed stability analysis of the existing caisson quay wall.
Arup developed a series of design options for the proposed quay wall structure and crane rail beam foundations. We also defined all electrical, pavement, drainage and quay furniture requirements for the project. This comprised an onsite review and desk top study of existing services. It included the provision of power supply to the high mast lighting, refer gantry, general site power and MV ducting for a Ship to Shore (STS) crane.
We prepared all tender documents for the works, including the reference design and Employer's Requirements. The works were tendered under the FIDIC Conditions of Contract for Plant and Design-Build (yellow book) and Arup was responsible for the complete tender management, including tender interviews and assessment. During construction, Arup provided the contract administration and full time supervision on site for the duration of the works.