Organized by SAEE and the Faculty of Civil Engineering in Belgrade, on May 8, 2019, a lecture was held by Prof. Dr. Peter Fajfar from the University of Ljubljana on the topic "Practice-oriented nonlinear seismic analysis of structures."
Abstract
The seismic response of a structure and its content can be assessed by an appropriate analysis. Since the nature of the problem is dynamic and, in most cases, nonlinear, the method that theoretically provides accurate results is nonlinear dynamic analysis — nonlinear response-history analysis. Additionally, since ground displacements during an earthquake are arbitrary and structural characteristics have a certain level of uncertainty, a probabilistic approach to the problem is necessary. However, considering financial and time constraints in structural design, as well as the level of knowledge of civil engineers in seismic design, simplified analysis methods are usually used in practice.
Despite various limitations, nonlinear static – pushover analysis methods often represent a rational option for practical assessment of the seismic response of structures. The relationship between factors determining seismic response can be more easily understood if the nonlinear static – pushover analysis is presented graphically, through acceleration-displacement (AD) dependency. The lecture emphasized the N2 pushover method. Both the basic version of this method, which is implemented in the current version of Eurocode 8, and an extended version, which accounts for higher mode effects and structural torsion and is included in the draft of the new Eurocode 8, were presented. Also shown was a method for the direct determination of acceleration spectra of inter-story floors, recently formulated and planned to be included in the new version of Eurocode 8 for seismic design and response assessment of non-structural (secondary) elements sensitive to inter-story floor accelerations.
The lecture slides (in PDF format) and video recordings are available to SAEE members with the consent of the lecturer.
Video recording of the lecture – Part I (lecture)
Video recording of the lecture – Part II (discussion)
Peter Fajfar is a professor at the Faculty of Civil and Geodetic Engineering, University of Ljubljana, Slovenia. His main research area is seismic analysis and design of structures. His most significant contribution in this field is the formulation of the N2 method, which is applied within the nonlinear static (pushover) analysis framework. He has been a visiting professor at several prestigious universities, including Stanford University in California. From 2003 to 2015, he was one of the three editors of the journal Earthquake Engineering and Structural Dynamics.
He served on the Board of the International Association for Earthquake Engineering (IAEE) and on the Executive Committee of the European Association for Earthquake Engineering (EAEE), where he is now an Honorary Member. He was involved in the development of Eurocode 8 and leads its implementation in Slovenia, which was the first country to adopt Eurocode 8 as a mandatory design standard for structures. As a designer, consultant, or reviewer, he has participated in numerous industrial projects. Together with H. Krawinkler, Professor Fajfar organized three well-known workshops in Bled, Slovenia (“Bled Workshops”). Professor Fajfar has received several awards, including the highest scientific award in Slovenia and the Nicholas Ambraseys Distinguished Lecture Award for outstanding lectures.
He is a member of the Slovenian Academy of Sciences and Arts, the Slovenian Academy of Engineering, the European Academy of Sciences (Belgium), and the National Academy of Engineering (USA).
Organized by SAEE and the Faculty of Civil Engineering in Belgrade, on May 8, 2019, a lecture was held by Prof. Dr. Peter Fajfar from the University of Ljubljana on the topic "Practice-oriented nonlinear seismic analysis of structures."
Abstract
The seismic response of a structure and its content can be assessed by an appropriate analysis. Since the nature of the problem is dynamic and, in most cases, nonlinear, the method that theoretically provides accurate results is nonlinear dynamic analysis — nonlinear response-history analysis. Additionally, since ground displacements during an earthquake are arbitrary and structural characteristics have a certain level of uncertainty, a probabilistic approach to the problem is necessary. However, considering financial and time constraints in structural design, as well as the level of knowledge of civil engineers in seismic design, simplified analysis methods are usually used in practice.
Despite various limitations, nonlinear static – pushover analysis methods often represent a rational option for practical assessment of the seismic response of structures. The relationship between factors determining seismic response can be more easily understood if the nonlinear static – pushover analysis is presented graphically, through acceleration-displacement (AD) dependency. The lecture emphasized the N2 pushover method. Both the basic version of this method, which is implemented in the current version of Eurocode 8, and an extended version, which accounts for higher mode effects and structural torsion and is included in the draft of the new Eurocode 8, were presented. Also shown was a method for the direct determination of acceleration spectra of inter-story floors, recently formulated and planned to be included in the new version of Eurocode 8 for seismic design and response assessment of non-structural (secondary) elements sensitive to inter-story floor accelerations.
The lecture slides (in PDF format) and video recordings are available to SAEE members with the consent of the lecturer.
Video recording of the lecture – Part I (lecture)
Video recording of the lecture – Part II (discussion)
Peter Fajfar is a professor at the Faculty of Civil and Geodetic Engineering, University of Ljubljana, Slovenia. His main research area is seismic analysis and design of structures. His most significant contribution in this field is the formulation of the N2 method, which is applied within the nonlinear static (pushover) analysis framework. He has been a visiting professor at several prestigious universities, including Stanford University in California. From 2003 to 2015, he was one of the three editors of the journal Earthquake Engineering and Structural Dynamics.
He served on the Board of the International Association for Earthquake Engineering (IAEE) and on the Executive Committee of the European Association for Earthquake Engineering (EAEE), where he is now an Honorary Member. He was involved in the development of Eurocode 8 and leads its implementation in Slovenia, which was the first country to adopt Eurocode 8 as a mandatory design standard for structures. As a designer, consultant, or reviewer, he has participated in numerous industrial projects. Together with H. Krawinkler, Professor Fajfar organized three well-known workshops in Bled, Slovenia (“Bled Workshops”). Professor Fajfar has received several awards, including the highest scientific award in Slovenia and the Nicholas Ambraseys Distinguished Lecture Award for outstanding lectures.
He is a member of the Slovenian Academy of Sciences and Arts, the Slovenian Academy of Engineering, the European Academy of Sciences (Belgium), and the National Academy of Engineering (USA).
