Seismic site investigation in Hull addresses the unique geological and industrial challenges of this historic Humber port city. The area is underlain by a complex sequence of Quaternary glacial deposits, including the Devensian till of the Skipsea Member and the associated Burnham Chalk Formation at depth, all of which influence seismic wave propagation and local site response. Understanding these ground conditions is essential for compliance with UK regulations, including the Building Regulations Approved Document A and the structural Eurocodes, specifically BS EN 1998-1:2004+A1:2013 for earthquake-resistant design. Our approach integrates geotechnical investigation with targeted geophysical surveys to map bedrock topography and identify potential seismic amplification zones within the superficial deposits. Detailed soil classification to BS 5930:2015+A1:2020 standards forms the foundation of every seismic assessment, ensuring that dynamic laboratory testing is performed on representative samples.
Our seismic methodology is firmly rooted in current UK standards and international best practice, combining invasive and non-invasive techniques to characterise the small-strain stiffness of the ground. We employ the Standard Penetration Test (SPT) in accordance with BS EN ISO 22476-3, often with energy calibration, to provide an initial correlation with shear wave velocity (Vs). This is complemented by advanced In-Situ methods, most critically the seismic cone penetration test (SCPTU) and multichannel analysis of surface waves (MASW), which directly measure Vs profiles. For projects requiring the assessment of hydraulic conductivity under dynamic conditions, we conduct field permeability tests using the Lefranc or Lugeon methods, particularly where soil liquefaction potential must be evaluated. All data is processed to derive the Site Class in accordance with BS EN 1998-1, providing the essential parameters for structural engineers to perform modal analysis and seismic design.
Typical projects in Hull and the wider East Riding demand a pragmatic seismic assessment due to the region's history of moderate seismicity and its critical infrastructure. We routinely support the development of tall structures on the deep soft alluvium of the Humber floodplain, where the contrast in impedance between the superficial deposits and the chalk bedrock can amplify ground motion. Our work is also essential for the Port of Hull's quay walls and heavy-lift pavements, for flood defence embankments where liquefaction of loose granular layers is a concern, and for the burgeoning renewable energy sector’s onshore substations and cable routes. A deep understanding of soil mechanics study principles, particularly critical state soil mechanics, allows us to model the cyclic degradation of strength and stiffness for these strategic assets, moving beyond simple linear-elastic assumptions.
The process begins with a desktop study to define the seismic hazard, followed by a phased field investigation designed to answer the specific questions of the design team. The final deliverable is a comprehensive Ground Investigation Report with a dedicated seismic annex, presenting Vs profiles, site class determination, and, where required, liquefaction potential indices and ground motion parameters. This is not a commodity output; it is a rigorous, interpretative document that provides clear recommendations for foundation design, earth pressures, and soil-structure interaction. By choosing a specialist who integrates geophysics with a complete suite of laboratory dynamic testing, including resonant column and cyclic triaxial tests, clients in Hull receive a defensible, code-compliant seismic design basis that de-risks their investment and ensures long-term structural resilience.