In an event organized by SAEE and the Faculty of Civil Engineering in Belgrade, on March 29, 2019, a lecture was held by Prof. Dr Božidar Stojadinović from ETH Zurich on the topic “Performance-Based Seismic Design – What is it? How is it applied in practice? And why?”.
Abstract
The concept of designing and verifying structures based on desired and specified performance entered earthquake engineering over two decades ago. Initially, it was a way to expand the design objective from a single goal (preventing collapse or structural failure) to multiple goals. Over time, performance-based design has evolved in three directions: 1) achieving specified performance without being tied to particular technologies; 2) probabilistic definition of performance objectives based on risk assessment; and 3) expanding the design objectives from damage control to facilitating rapid recovery, and from individual structural elements to groups of buildings and interdependent infrastructure systems forming the built inventory of settlements and cities.
Faced with this expanded design scope, civil engineers need guidance on how to design for specified performance. Only a few of the many methods developed in academia have been accepted in practice. Two methods were emphasized: one is nonlinear static pushover analysis of structural response under equivalent lateral loading corresponding to a defined seismic hazard level, and the other is probabilistic incremental dynamic analysis (IDA) of structural response, which determines the seismic risk level to which a structure is exposed. Using these methods, engineers can assess the seismic vulnerability of a structure and determine the likelihood that the structure will meet desired performance criteria. By applying additional tools for estimating direct and indirect damage, engineers can quantify expected monetary losses from a single earthquake or over the structure’s lifetime, as well as aggregate these monetary loss estimates for groups of buildings and infrastructure systems within a settlement.
Designing or verifying structures according to specified performance significantly increases the workload for civil engineers. Moreover, the tools and time required to demonstrate that the design meets the desired performance substantially raise the cost that investors must pay compared to conventional design following existing codes focused on structural safety and collapse prevention. Despite the higher cost, probabilistic performance-based design is sought for two reasons. First, investors want to assess risk over the structure’s lifetime to manage their portfolio risk and apply appropriate financial protection measures (e.g., insurance). Second, engineers must demonstrate the advantages and quality of their advanced designs, which surpass conventional solutions and justify the additional project or assessment costs.
Performance-based design is inevitable. It is becoming part of modern regulations and modern computerized tools for structural analysis and design—not only for seismic design but also for designing structures under other loads (e.g., fire resistance) and other system design areas (e.g., sustainable, resilient, and recoverable system design). The adoption of performance-based design is the future of civil engineering, both in practice and in research and education.
Slides from the lecture (in PDF format) and video recordings are available to SAEE members with the lecturer’s consent.
Video recording of the lecture – Part I (lecture)
Video recording of the lecture – Part II (discussion)
Speaker Biography
Prof. Dr Božidar Stojadinović is the Head of the Chair for Structural Dynamics and Earthquake Engineering at the Swiss Federal Institute of Technology (ETH) in Zurich and a member of the ETH Risk Center. Before joining ETH in July 2011, he was a professor at the University of California, Berkeley, and at the University of Michigan, Ann Arbor. He earned his PhD in 1995 at the University of California, Berkeley, his master's degree in 1990 at Carnegie Mellon University in Pittsburgh, and his undergraduate degree in 1988 at the Faculty of Civil Engineering, University of Belgrade.
Community disaster resilience is Professor Stojadinović’s main research area. He applies probabilistic performance-based design for assessing existing and designing new infrastructure systems, buildings, and bridges. Another area of his work is applying performance-based design principles to develop new methods for modifying the dynamic response of structures (e.g., seismic isolation and rocking) to protect them from earthquakes, as well as developing new methods for seismic design and structural assessment. A third area covers developing new experimental methods, such as hybrid simulation, where structural dynamic behavior is modeled using a hybrid model consisting of physical and numerical elements. He has published over 350 scientific papers presenting his research results.
At ETH, Prof. Stojadinović teaches courses on earthquake engineering, structural dynamics, and statics. At Berkeley and Michigan, he taught courses on steel design, experimental methods, finite element methods, earthquake engineering, statics, material strength, and mechanics. He has supervised 38 PhD students.
Selected publications on performance-based seismic design, listed chronologically:
- Hamburger (1996), "Implementing performance based seismic design in structural engineering practice"
http://www.iitk.ac.in/nicee/wcee/article/11_2121.PDF
- Bertero (1996), "The need for multi-level seismic design criteria"
http://www.iitk.ac.in/nicee/wcee/article/11_2120.PDF
- Holmes (2000), "A vision for a complete performance-based earthquake engineering system"
http://www.iitk.ac.in/nicee/wcee/article/0836.pdf
- Hamburger (2004), "The ATC-58 Project: Development of next-generation performance-based earthquake engineering design criteria for buildings"
http://www.iitk.ac.in/nicee/wcee/article/13_1819.pdf
- Hamburger i ostali (2012), "FEMA P58: Next-Generation Building Seismic Performance Assessment Methodology"
http://www.iitk.ac.in/nicee/wcee/article/WCEE2012_4156.pdf
- Online biblioteka NEHRP-a
https://www.nehrp.gov/library/guidance_pbsd.htm
In an event organized by SAEE and the Faculty of Civil Engineering in Belgrade, on March 29, 2019, a lecture was held by Prof. Dr Božidar Stojadinović from ETH Zurich on the topic “Performance-Based Seismic Design – What is it? How is it applied in practice? And why?”.
Abstract
The concept of designing and verifying structures based on desired and specified performance entered earthquake engineering over two decades ago. Initially, it was a way to expand the design objective from a single goal (preventing collapse or structural failure) to multiple goals. Over time, performance-based design has evolved in three directions: 1) achieving specified performance without being tied to particular technologies; 2) probabilistic definition of performance objectives based on risk assessment; and 3) expanding the design objectives from damage control to facilitating rapid recovery, and from individual structural elements to groups of buildings and interdependent infrastructure systems forming the built inventory of settlements and cities.
Faced with this expanded design scope, civil engineers need guidance on how to design for specified performance. Only a few of the many methods developed in academia have been accepted in practice. Two methods were emphasized: one is nonlinear static pushover analysis of structural response under equivalent lateral loading corresponding to a defined seismic hazard level, and the other is probabilistic incremental dynamic analysis (IDA) of structural response, which determines the seismic risk level to which a structure is exposed. Using these methods, engineers can assess the seismic vulnerability of a structure and determine the likelihood that the structure will meet desired performance criteria. By applying additional tools for estimating direct and indirect damage, engineers can quantify expected monetary losses from a single earthquake or over the structure’s lifetime, as well as aggregate these monetary loss estimates for groups of buildings and infrastructure systems within a settlement.
Designing or verifying structures according to specified performance significantly increases the workload for civil engineers. Moreover, the tools and time required to demonstrate that the design meets the desired performance substantially raise the cost that investors must pay compared to conventional design following existing codes focused on structural safety and collapse prevention. Despite the higher cost, probabilistic performance-based design is sought for two reasons. First, investors want to assess risk over the structure’s lifetime to manage their portfolio risk and apply appropriate financial protection measures (e.g., insurance). Second, engineers must demonstrate the advantages and quality of their advanced designs, which surpass conventional solutions and justify the additional project or assessment costs.
Performance-based design is inevitable. It is becoming part of modern regulations and modern computerized tools for structural analysis and design—not only for seismic design but also for designing structures under other loads (e.g., fire resistance) and other system design areas (e.g., sustainable, resilient, and recoverable system design). The adoption of performance-based design is the future of civil engineering, both in practice and in research and education.
Slides from the lecture (in PDF format) and video recordings are available to SAEE members with the lecturer’s consent.
Video recording of the lecture – Part I (lecture)
Video recording of the lecture – Part II (discussion)
Speaker Biography
Prof. Dr Božidar Stojadinović is the Head of the Chair for Structural Dynamics and Earthquake Engineering at the Swiss Federal Institute of Technology (ETH) in Zurich and a member of the ETH Risk Center. Before joining ETH in July 2011, he was a professor at the University of California, Berkeley, and at the University of Michigan, Ann Arbor. He earned his PhD in 1995 at the University of California, Berkeley, his master's degree in 1990 at Carnegie Mellon University in Pittsburgh, and his undergraduate degree in 1988 at the Faculty of Civil Engineering, University of Belgrade.
Community disaster resilience is Professor Stojadinović’s main research area. He applies probabilistic performance-based design for assessing existing and designing new infrastructure systems, buildings, and bridges. Another area of his work is applying performance-based design principles to develop new methods for modifying the dynamic response of structures (e.g., seismic isolation and rocking) to protect them from earthquakes, as well as developing new methods for seismic design and structural assessment. A third area covers developing new experimental methods, such as hybrid simulation, where structural dynamic behavior is modeled using a hybrid model consisting of physical and numerical elements. He has published over 350 scientific papers presenting his research results.
At ETH, Prof. Stojadinović teaches courses on earthquake engineering, structural dynamics, and statics. At Berkeley and Michigan, he taught courses on steel design, experimental methods, finite element methods, earthquake engineering, statics, material strength, and mechanics. He has supervised 38 PhD students.
Selected publications on performance-based seismic design, listed chronologically:
- Hamburger (1996), "Implementing performance based seismic design in structural engineering practice"
http://www.iitk.ac.in/nicee/wcee/article/11_2121.PDF
- Bertero (1996), "The need for multi-level seismic design criteria"
http://www.iitk.ac.in/nicee/wcee/article/11_2120.PDF
- Holmes (2000), "A vision for a complete performance-based earthquake engineering system"
http://www.iitk.ac.in/nicee/wcee/article/0836.pdf
- Hamburger (2004), "The ATC-58 Project: Development of next-generation performance-based earthquake engineering design criteria for buildings"
http://www.iitk.ac.in/nicee/wcee/article/13_1819.pdf
- Hamburger i ostali (2012), "FEMA P58: Next-Generation Building Seismic Performance Assessment Methodology"
http://www.iitk.ac.in/nicee/wcee/article/WCEE2012_4156.pdf
- Online biblioteka NEHRP-a
https://www.nehrp.gov/library/guidance_pbsd.htm
