Queensferry Crossing, UK: foundations and geotechnical works

Each foundation for the Queensferry Crossing road bridge over the Firth of Forth in Scotland, UK, required significant investigation and technical development to deliver a successful project. The tender stage decision to use only mass footings for the crossing placed an emphasis on clear understanding of the geology, application of this understanding in analysis and the verification of these conditions during construction. This paper summarises the collaborative approach between the contractor, designer and employer used for investigation, analysis and design of permanent and temporary works with substantive dialogue started during the tendering process. Post contract award this dialogue continued with collective agreement on the performance indicators that would define success to allow continuation of the construction of the permanent works. This approach resulted in a construction process that permitted speedy resolution of issues such as the encounter of unexpected rock conditions or localised breaching of temporary cofferdams that would have created substantial delay on projects of a similar scale and complexity. Construction included the use of underwater inspection techniques that were unique to this project.