Acceptable risk bases for design of structures

Abstract Structural design standards provide the foundation of good engineering practice and a framework for addressing safety and serviceability issues rationally. Structural reliability methods provide the tools for managing uncertainties in modern codified structural design. Current probability‐based structural codes are based on performance measures expressed as notional reliabilities of structural components. These notional reliabilities, encapsulated in reliability indices, were obtained by calibrating the proposed codes to traditional practice rather than from quantitative risk analysis. Because the reliability estimates are based on models of real systems, they may not correspond to historical failure rates, and therefore confound the process of risk communication among structural engineers, building or regulatory officials, and the public. The research and professional engineering communities must work together to confront future challenges arising from new trends in structural engineering practice towards tailoring building design to performance expectations of the building owners, occupants and the public. In this context, the prospects of basing future codes on a quantitative acceptable risk measure warrant further examination.