This is a characteristic example of a “high risk – high gain” project, where we all focus on the scientific gain and tend to deliberately overlook the associated risk (and the pain).

HYSTERESIS is, without any doubt, the most complex and challenging test we ever performed in SoFSI: The UKCRIC Soil-Foundation-Structure Interaction Laboratory not only as part of ERIES: Engineering Research Infrastructures for European Synergies but also since the facility became operational in 2022. Representing soil behaviour physically introduced a number of practical and scientific uncertainties, particularly related to the stability of the hybrid simulation algorithm and the overall fidelity of the test. Furthermore and quite interestingly, the relative contribution of strongly coupled and concurrent phenomena (i.e., soil plasticity, rotation at the soil-foundation interface, uplift at the CLT wall-foundation interface and the energy dissipation provided by the BRBs and sand dampers ) could only be fully understood at the end of the test.

The successful execution of this geographically distributed hybrid experiment is solid evidence of the current capabilities to interconnect complementary research infrastructures and combine multiple physical phenomena within a single framework. It also highlights the potential of hybrid simulation to experimentally investigate aspects of resilient structural behaviour that are highly uncertain while modelling numerically those that we understand better.

Even if, in fairness, we faced the risk of not delivering the test successfully, the knowledge gained and the excellent collaboration between all partners was very much worth all the effort and the risk involved.