Seismic design and assessment of bridges using advanced inelastic analysis tools
Event details
| Date | 02.05.2014 |
| Hour | 12:15 › 13:15 |
| Speaker | Prof. Andreas Kappos (City University, UK) |
| Location |
GC C330
|
| Category | Conferences - Seminars |
Modern codes for seismic design of buildings, bridges, and other civil engineering structures offer to the designer the choice between elastic and inelastic analysis methods, i.e.
• ‘Traditional’ methods wherein design is based on the results of a series of elastic analyses that provide linear action effects that are reduced by a global force reduction factor (q-factor in Europe, R-factor in the US) that depends on the overall ductility and overstrength capacity of the structure.
• Displacement and/or deformation based methods, wherein inelastic deformation demands in the structure are estimated for a given level of the seismic action with the aid of a series of inelastic analyses of either the static or dynamic type. These demands are then checked against the corresponding deformation capacities of the critical structural elements.
Over the last two decades, researchers and engineers have gradually shifted towards the performance-based assessment and design concept, wherein inelastic deformation demands are (preferably) directly obtained from the aforementioned nonlinear response analysis of the structure. The safety verification then involves comparing these demands against the deformation capacities to verify the performance of the structure with respect to a given performance objective (e.g. allowable member rotation for ensuring life safety under a ground motion having an appropriately selected probability of occurrence). This type of analysis is more suitable for the assessment of existing structures (where member strengths can be calculated before carrying out the analysis) than for the design of new ones.
The lecture will focus on the use of inelastic analysis methods for the seismic assessment and design of bridges, for which the work carried out so far, albeit interesting and useful, is nevertheless clearly less than that for buildings. A critical overview of nonlinear static (pushover) methods that account for higher mode effects (which are typically significant in bridges) will be given, along with comparisons with response-history analysis results.
In addition to analysis methods, the lecture will include a presentation of a deformation-based design method that can be applied to bridges with several significant modes.
Bio: Prior to joining City University (in March 2013) Andreas Kappos was a Professor at Department of Civil Engineering, of the Aristotle Univ. of Thessaloniki since 2002, and Head of the Structures Section from 2008 to 2010. He has first joined the Department as a lecturer in 1988, after having completed his PhD studies in 1986. In 1983-1984 he was a Visiting Research Fellow at the Univ. of California, Berkeley. From 1995 to 1999 he worked at the Dept. of Civil Engineering, Imperial College London (UK), first as a lecturer and later as a Reader of Earthquake Structural Engineering.
Andreas Kappos is the Secretary of the European Association of Earthquake Engineering (EAEE) since 2010 and the Coordinator of the EAEE Working Group on Bridges since 2004. He has also served as a member of a number of scientific committees dealing with seismic design (incl. the Eurocode 8 Project Team) and assessment (various fib and EAEE task groups).
• ‘Traditional’ methods wherein design is based on the results of a series of elastic analyses that provide linear action effects that are reduced by a global force reduction factor (q-factor in Europe, R-factor in the US) that depends on the overall ductility and overstrength capacity of the structure.
• Displacement and/or deformation based methods, wherein inelastic deformation demands in the structure are estimated for a given level of the seismic action with the aid of a series of inelastic analyses of either the static or dynamic type. These demands are then checked against the corresponding deformation capacities of the critical structural elements.
Over the last two decades, researchers and engineers have gradually shifted towards the performance-based assessment and design concept, wherein inelastic deformation demands are (preferably) directly obtained from the aforementioned nonlinear response analysis of the structure. The safety verification then involves comparing these demands against the deformation capacities to verify the performance of the structure with respect to a given performance objective (e.g. allowable member rotation for ensuring life safety under a ground motion having an appropriately selected probability of occurrence). This type of analysis is more suitable for the assessment of existing structures (where member strengths can be calculated before carrying out the analysis) than for the design of new ones.
The lecture will focus on the use of inelastic analysis methods for the seismic assessment and design of bridges, for which the work carried out so far, albeit interesting and useful, is nevertheless clearly less than that for buildings. A critical overview of nonlinear static (pushover) methods that account for higher mode effects (which are typically significant in bridges) will be given, along with comparisons with response-history analysis results.
In addition to analysis methods, the lecture will include a presentation of a deformation-based design method that can be applied to bridges with several significant modes.
Bio: Prior to joining City University (in March 2013) Andreas Kappos was a Professor at Department of Civil Engineering, of the Aristotle Univ. of Thessaloniki since 2002, and Head of the Structures Section from 2008 to 2010. He has first joined the Department as a lecturer in 1988, after having completed his PhD studies in 1986. In 1983-1984 he was a Visiting Research Fellow at the Univ. of California, Berkeley. From 1995 to 1999 he worked at the Dept. of Civil Engineering, Imperial College London (UK), first as a lecturer and later as a Reader of Earthquake Structural Engineering.
Andreas Kappos is the Secretary of the European Association of Earthquake Engineering (EAEE) since 2010 and the Coordinator of the EAEE Working Group on Bridges since 2004. He has also served as a member of a number of scientific committees dealing with seismic design (incl. the Eurocode 8 Project Team) and assessment (various fib and EAEE task groups).
Practical information
- General public
- Free
Organizer
- Prof. Nikolas Geroliminis & Prof. Katrin Beyer
Contact
- Prof. Katrin Beyer