Large-diameter open caissons are a widely used construction solution for deep foundations, underground storage and attenuation tanks, pumping stations, and launch and reception shafts for tunnel boring machines. The sinking phase presents a number of challenges during construction, including maintaining caisson verticality, controlling the rate of sinking and minimising soil resistance through the use of lubricating fluids.

This lecture will describe the instrumentation and monitoring of a large-diameter caisson on a UK construction site. The caisson was instrumented for the measurement of settlement and tilt, soil-structure interaction contact stresses and structural performance.

A key objective for the monitoring project was to provide real-time feedback to the site engineering team to inform the construction process. The monitored data revealed the occurrence of complex soil-structure interactions during sinking that are not readily captured by existing prescriptive design approaches.

This case history provides valuable information for the development of an improved basis for design as well as an important frame of reference for future monitoring projects.

Dr Ronan Royston, Engineer, Ward & Burke Construction

Dr. Ronan Royston oversees the design and delivery of major infrastructure projects for Ward and Burke Construction across the UK and Ireland, with particular focus in the Water Industry. He employs an interdisciplinary approach encompassing geotechnical, structural, electrical, and mechanical design, through the procurement, construction, commissioning, and operational stages. Ronan completed his DPhil at the University of Oxford, focusing on soil-structure interaction for large diameter caissons. His research concentrated on the design and construction of underground pumping stations and tunnels. In recognition of his contributions to engineering, Ronan was awarded the James Rennie Medal for best Chartered Engineer by the ICE in 2022. He also serves as an Adjunct Associate Professor in Civil Engineering at the University of Limerick.

Dr Brian Sheil, Laing O'Rourke Associate Professor in Construction Engineering, University of Cambridge

Dr Brian Sheil studied Civil Engineering for his undergraduate degree at the National University of Ireland, Galway (NUIG). He studied the behaviour of deep foundation systems for his PhD (also at NUIG), which involved a period as a Visiting Scholar at the University of California, Berkeley. In 2014, Brian joined the University of Oxford as a postdoctoral researcher in experimental geotechnics focused on industry-funded research projects and was subsequently promoted to Departmental Lecturer in geotechnical engineering in 2017. In 2018, he was awarded a Royal Academy of Engineering Research Fellow at Oxford. He took up his current position as the Laing O'Rourke Associate Professor in Construction Engineering at University of Cambridge in 2022. In January 2024 he became Director of the Centre for Smart Infrastructure and Construction, also at Cambridge.

Professor Byron Byrne, Professor of Engineering Science, University of Oxford

Professor Byron Byrne holds the Ørsted / Royal Academy of Engineering Research Chair in Advanced Geotechnical Design at the University of Oxford, where he pursues a wide-ranging research program in geotechnical engineering. He works collaboratively with industry to solve practical problems applying experimental work, at both laboratory scale and larger scale in the field, theoretical analysis and computational techniques, to develop simplified design methods for the engineer. He has a specific interest in offshore geotechnics, principally the design of foundations for offshore wind turbines, but also offshore pipeline design, as well as for onshore infrastructure activities, including pipelines, caissons, and other related soil-structure interaction problems. He is a Fellow of the Royal Academy of Engineering and of the Institution of Civil Engineers.