SEISMIC PERFORMANCE OBJECTIVES: ADEQUATE FOR COMMUNITY RESILIENCE?

TY - GEN

T1 - SEISMIC PERFORMANCE OBJECTIVES

T2 - ADEQUATE FOR COMMUNITY RESILIENCE?

AU - Tsang, H. H.

AU - Daniell, J. E.

AU - Wenzel, F.

AU - Wilson, J. L.

N1 - Copyright: © 2024, International Association for Earthquake Engineering. All rights reserved.

PY - 2021

Y1 - 2021

N2 - Structural engineers design buildings and infrastructure according to the earthquake action to a certain level of return period specified in the code of practice, whilst the rationale behind such requirement is commonly untold. In fact, even if a structure is designed strictly in conformance with a modern code of practice, there is still a small chance of failure or collapse in an extreme earthquake event, due to the uncertainties in material properties and actual ground motion characteristics. This residual risk should be taken as a governing parameter for determining or evaluating the performance goals of seismic design. Various approaches have been implemented or proposed in the last decade for setting risk-based performance requirements for seismic design. But then, how safe is safe enough? Are they adequate for ensuring community resilience after an earthquake? This is a missing piece of knowledge in seismic design. This paper attempts to provide this missing piece by evaluating whether the stipulated performance objectives are adequate for community resilience or not. The earthquake fatality risk for society is estimated based on regional earthquake loss modelling for Melbourne, Australia, which is a region of lower seismicity. This is then benchmarked against a regulatory requirement based on an approach proposed by the authors for evaluating the adequacy of existing code level for life safety and community resilience. The results show that the earthquake fatality risk for society appears to be unacceptable. There is a common belief amongst engineering professionals that it is uneconomical to design structures to resist stronger earthquakes. However, the public has never/rarely been asked about their preferences actually. Recent research has shown that building owners are indeed willing to pay for better earthquake protection and resilience (i.e. habitable or functional after a major earthquake event). As the consequences of structural failure concern life safety, an ideal building code should indicate the expected level of fatality risk since it is a legal document that sets forth requirements for protecting life and ensuring community resilience. The research outcomes presented are important resources for guiding the development of future editions of seismic codes globally.

AB - Structural engineers design buildings and infrastructure according to the earthquake action to a certain level of return period specified in the code of practice, whilst the rationale behind such requirement is commonly untold. In fact, even if a structure is designed strictly in conformance with a modern code of practice, there is still a small chance of failure or collapse in an extreme earthquake event, due to the uncertainties in material properties and actual ground motion characteristics. This residual risk should be taken as a governing parameter for determining or evaluating the performance goals of seismic design. Various approaches have been implemented or proposed in the last decade for setting risk-based performance requirements for seismic design. But then, how safe is safe enough? Are they adequate for ensuring community resilience after an earthquake? This is a missing piece of knowledge in seismic design. This paper attempts to provide this missing piece by evaluating whether the stipulated performance objectives are adequate for community resilience or not. The earthquake fatality risk for society is estimated based on regional earthquake loss modelling for Melbourne, Australia, which is a region of lower seismicity. This is then benchmarked against a regulatory requirement based on an approach proposed by the authors for evaluating the adequacy of existing code level for life safety and community resilience. The results show that the earthquake fatality risk for society appears to be unacceptable. There is a common belief amongst engineering professionals that it is uneconomical to design structures to resist stronger earthquakes. However, the public has never/rarely been asked about their preferences actually. Recent research has shown that building owners are indeed willing to pay for better earthquake protection and resilience (i.e. habitable or functional after a major earthquake event). As the consequences of structural failure concern life safety, an ideal building code should indicate the expected level of fatality risk since it is a legal document that sets forth requirements for protecting life and ensuring community resilience. The research outcomes presented are important resources for guiding the development of future editions of seismic codes globally.

KW - Building

KW - Community resilience

KW - Fatality

KW - Life safety

KW - Performance goal/objective

KW - Residual risk

KW - Societal

UR - https://www.scopus.com/pages/publications/105027857737

M3 - Conference contribution

AN - SCOPUS:105027857737

VL - 2021

BT - World Conference on Earthquake Engineering Online Proceedings

PB - International Association for Earthquake Engineering

ER -