Application of Probabilistic Robustness Framework: Risk Assessment of Multi-Storey Buildings under Extreme Loading

Abstract

Risk assessment is a requirement for robustness design of high consequence class structures, yet very little guidance is offered in practice for performing this type of assessment. This paper demonstrates the application of the probabilistic risk assessment framework arising from COST Action TU0601 to multi-storey buildings subject to extr eme loading. A brief outline of the probabilistic framework is first provided, including the main requirements of describi ng uncertainty in the hazards and the associated local damage as wel l as the consequences of global failure. From a practical application perspectiv e, it is emphasised that there is a need for (a) computationally efficient deterministic models of global failure for specific local damage scenarios, and (b) effective probabilistic simulation methods that can establish the conditional probability of global failure on local damage. In this respect, this work utilises a recently developed multi-level deterministic assessment framework for multi-storey buildings subject to sudden column loss, which is coupled with a response surface approach utilising firstorder reliability methods to establish the conditional probability of failure. The application of the proposed approach is illustrated to a multi-storey steelcomposite building, where it is demonstrated that probabilistic risk assessment is a practical prospe ct. The paper concludes with a critical appraisal of probabilistic risk assessment, highlighting areas of future improvement.

09.10: Shear damage evaluation of bolted steel joints

“…The prescriptive approach is therefore questioned and better ways of establishing the ultimate performance of multi-storey buildings are sought. One approach is the multi-level deterministic assessment, as presented in [8]. This probabilistic framework couples the sudden column loss scenario with a response surface approach, by using first-order reliability methods to establish the conditional probability of failure.…”

“…The approach considers the pseudo-static capacity of the structure determined as a function of the structural configuration (geometry), material response and connection strength and ductility. The authors [8] acknowledge that the behaviour of composite floor systems is largely determined by the connection response and therefore the structural capacity becomes dominated by the uncertainty of the strength and ductility of the connecting components. By performing numerical simulations of T-stub's assuming different fractiles of the lognormal distribution curve for end-plate and bolt strength the authors find the T-stub's deformation capacity (the component governing ductility behaviour of joints) to be the one with the largest uncertainty, with a coefficient of variation of 0.15.…”