This paper concerns the problem of design seismic performance of R/C frames with flexible foundations. Analysis is carried out by capacity spectrum method assuming two parametric nonlinear soil model and inelastic behaviour of structural R/C members. The overall structural model includes R/C part and flexible foundations. An additional rotational degree of freedom is implemented to capture foundation rocking motion. To do this “soil type” plastic hinge is proposed. Soil deformations are calculated through site-specific data such as unit foundation modulus and soil capacity. Capacity spectrum is then calculated considering coupled structure-foundation system. Two categories of results for target displacements are compared and analyzed—first for fixed base structure and second for structure with flexible foundation. The case of fixed base structure is used as reference case. Numerical results are graphically illustrated. An analytical estimate for target displacement—behaviour factor relationship is proposed. It allows for displacement-based control on seismic demands. Basing on the numerical results it is concluded that in general foundation flexibility influences the overall structural response. Due to soil deformations target displacements are larger than corresponding target displacements of the fixed-base structure. Foundation flexibility reduces the global ductility of structure. Displacement demands can effectively be controlled by suitable choice of behaviour factor. This procedure creates opportunity for displacement-based seismic design.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsPreview
Unable to display preview. Download preview PDF.
References
Blagov, D., Georgiev, V., and Bonev, Z. (2008) Influence of flexible foundations on the design response of buildings with accidental eccentricity. Proceeding of the Fifth European Workshop on the Seismic Behaviour of Irregular and Complex Structures, pp. 375–386, 16–17 September 2008, Catania, Italy.
Bonev, Z., Ganchev, S., Blagov, D., and Zerzour, A. (2005) Factor evaluation accounting for the elastic foundation. In Proc. EE-21C, Topic 4: Structural Modelling, Analysis, Design and Seismic Safety, Skopje, Republic of Macedonia.
Chopra, A. and Goel, R. (1999) Capacity-demand diagram methods for estimating seismic deformation of inelastic structures: SDOF systems, A Report on Research Conducted under Grant No. CMS-9812531, US-Japan Cooperative Research in Urban Earthquake Disaster Mitigation, from the National Science Foundation, Report No. PEER-1999/02 Pacific Earthquake Engineering Research Center, College of Engineering University of California, Berkeley.
Chopra, A. K. and Goel, R. (2003) Evaluation of the modal pushover analysis procedure using vertically “regular” and irregular generic frames, Report No. EERC 2003-03, University of California, Berkeley.
EN 1992-1-1 (2004) Eurocode 2: Design of Concrete Structures, Part 1-1: General Rules and Rules for Buildings, December.
EN 1997-1 (2004) Eurocode 7: Geotechnical Design, Part 1: General Rules, November.
EN 1998 (2004) Parts 1 and 5, Eurocode 8: Design of Structures for Earthquake Resistance, Part 1: General Rules, Seismic Actions and Rules for Buildings (EN 1998-1), December.
Fajfar, P. (1999) Capacity spectrum method based on inelastic demand spectra, Earthquake Engineering and Structural Dynamics 28, 979–993.
Fajfar, P. (2000) A nonlinear analysis method for performance-based seismic design, Earthquake Spectra 16(3), 573–592.
Fajfar, P. and Marusic, D. (2005) The extension of N2-method to asymmetric buildings. In Proc. 4th EWICS (European Workshop on the Seismic Behaviour of Irregular and Complex Structures), Thessaloniki, Greece.
FEMA 273 (1997) NEHRP Guidelines for the Seismic Rehabilitation of Buildings, Issued by FEMA in Furtherance of the Decade for National Disaster Reduction, October.
FEMA 274 (1998) Seismic Rehabilitation Commentary C4: Foundations and Geotechnical Hazards.
FEMA 357 (2000) Global Topics Report on the Prestandard and Commentary for the Seismic Rehabilitation of Buildings, Prepared by American Society of Civil Engineers, Reston, Virginia.
FEMA 450 (2003) NEHRP Recommended Provisions for Seismic Regulations for New Buildings and Other Structures, Commentary C7A.
Gazetas, G. and Apostolou, M. (2004) Nonlinear soil-structure interaction: Foundation uplifting and soil yielding. In Proc. 3rd UJNR Workshop on Soil-Structure Interaction, Menlo Park, California, USA.
Geotechnical Engineering, Circular No. 3 (1997) Design Guidance: Geotechnical Earthquake Engineering for Highways, Publication No. FHWA-SA-97-076, Vol. 1: Design Principles, US Department of Transportation, Federal Highway Administration, Office of Engineering, Office of Technology Applications, 400 Seventh street SW, Washington, DC 20 590, May, 1997.
El Naggar, H. M. (2003) Seismic response of structures with underground storeys, JCLR Research Paper Series, No. 26, Institute for Catastrophic Loss Prediction, University of Western Ontario.
Kilar, V. and Fajfar, P. (2000) Simplified nonlinear seismic analysis of asymmetric multistorey R/C building. In Proc. 12th European Conference on Earthquake Engineering, Pap. Ref. 033.
Kramer, S. L. (1996) Geotechnical Earthquake Engineering, Prentice-Hall International Series in Civil Engineering and Engineering Mechanics, Upper Saddle River, New Jersey.
Paulay, T. and Priestley, M. J. N. (1992) Seismic Design of Reinforced Concrete and Masonry Buildings, John Wiley & Sons, New York.
PERFORM 3D v. 4 (2006) Nonlinear Analysis and Performance Assessment of Structures, CSI, Berkeley, California, August.
SAP 2000 (1997) Integrated Finite Element Analysis and Design of Structures, CSI, Berkeley, California.
Schanz, T., Bonev, Z., Georgiev, V., and Iankov, R. (2007) Application of capacity spectrum method to soil-foundation-structure interaction problems. In Proc. of the Jubilee Scientific Conference, Devoted to 65 years Anniversary of the University of Architecture, Civil Engineering and Geodesy, Sofia, Bulgaria.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2009 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Schanz, T., Bonev, Z., Wuttke, F., Iankov, R., Georgiev, V. (2009). Design seismic performance of R/C framestructures taking into account foundation flexibility. In: Schanz, T., Iankov, R. (eds) Coupled Site and Soil-Structure Interaction Effects with Application to Seismic Risk Mitigation. NATO Science for Peace and Security Series C: Environmental Security. Springer, Dordrecht. https://doi.org/10.1007/978-90-481-2697-2_19
Download citation
DOI: https://doi.org/10.1007/978-90-481-2697-2_19
Publisher Name: Springer, Dordrecht
Print ISBN: 978-90-481-2709-2
Online ISBN: 978-90-481-2697-2
eBook Packages: EngineeringEngineering (R0)