MSc Dissertation - Selection & Scaling of Natural Earthquake Records for Inelastic Analysis of Reinforced Concrete Structures
- 1. Selection and Scaling of Natural Earthquake Records for Inelastic Analysis of Reinforced Concrete Structures MSc Dissertation by Konstantinos Myrtsis Project Supervisor: Dr. J.E Martinez-Rueda School of Environment and Technology MSc Civil Engineering September 2015
- 2. Konstantinos Myrtsis – MSc Civil Engineering 2 Abstract This dissertation addresses the influence of selection and scaling of natural earthquake records on the variability of the estimated seismic demands of inelastic reinforced concrete structures when analysed through non-linear time-history analysis. By using a database of 148 input ground motions which were recorded on firm soil, sample sizes of 4, 7, and 11 earthquake records with best, average, and worst spectral matching with the associated EC8 target design spectrum were generated. The implemented scaling criteria were based on four spectral intensity scales, as well as three levels of seismicity. The combined criteria under consideration required a total of 396 non-linear time-history analyses, while the total earthquake cases which produced the output of this research is calculated to 2214 cases of earthquakes. The results are assessed in terms of the estimation of the structural responses expressed as mean and peak displacement ductility demands of the critical floors of the three- storey structure under study.
- 3. Konstantinos Myrtsis – MSc Civil Engineering 3 Chapter 1 Introduction Preview This chapter includes introductory information on the challenge of using appropriately modified natural earthquake records for performing non-linear structural analysis. A detailed outline of this present scientific research on selection and scaling of natural earthquake records for inelastic analysis of reinforced concrete structures is included, followed by a description of the aim, the objectives and the importance of the project.
- 4. Konstantinos Myrtsis – MSc Civil Engineering 4 Chapter 2 Background Preview This chapter contains information and the suggested output from existing literature about the application of selecting and modifying ground motions for performing inelastic analysis of structures. Reference on current seismic code provisions in Europe and the United States is given, as well as a brief introduction on seismology is included.
- 5. Konstantinos Myrtsis – MSc Civil Engineering 5 Chapter 3 Methodology Preview This chapter contains detailed information on the methodology which was followed for the selected analyses to investigate the effect of selecting and scaling natural accelerograms on the response of inelastic reinforced concrete structures. The method includes all stages of procedure in a step by step sequence relative to the actions which were taken, from modelling and setting the properties of the inelastic reinforced concrete structure, defining the loads on the structure to processing the database of natural earthquake motions which were used for the purpose of this research.
- 6. Konstantinos Myrtsis – MSc Civil Engineering 6 Chapter 4 Results Preview This chapter contains the research results. The output from processing the natural earthquake records is presented, the computed scaling factors are provided, the outcome of the pushover analysis as well as the output of the time-history analysis are contained in this chapter. This section also illustrates the response of the RC structure under consideration from randomly selected cases of earthquake excitations.
- 7. Konstantinos Myrtsis – MSc Civil Engineering 7 Chapter 5 Discussion of results Preview In the following chapter, the elaboration of the results of the inelastic analysis will be given. The main focus of the discussion is on the influence of the number of records for analysis, the spectral matching under consideration and the scaling procedure which was used for analysis, as well as to identify correlation with the findings of existing experimental procedures in the current literature. Additionally, although assessing the structural integrity of the reinforced concrete structure may be beyond the scope of this study, a brief reference to the seismic performance of the structure subjected to a randomly selected earthquake motion will be provided.
- 8. Konstantinos Myrtsis – MSc Civil Engineering 8 Chapter 6 Conclusions Preview This section contains the implementation of the suggested output of this research regarding the influence of selecting and scaling real accelerograms on the output of non-linear time-history analysis. Additionally, recommendations for possible future studies will be provided.
- 9. Konstantinos Myrtsis – MSc Civil Engineering 9 List of References Akkar, S., & Ay, B. O. (2010). Selecting and Scaling of Real Accelerograms. Turkey: Middle East Technical University. Ambraseys, N. N., Douglas, J., Sarma, K., & Smit, P. M. (2005). Equations for the Estimation of Strong Ground Motions from Shallow Crustal Earthquakes Using Data from European and Middle East: Horizontal Peak Ground Acceleration and Spectral Acceleration. Bulletin of Earthquake Engineering, 3(1), 1.-53. Anaxagoras, E. (2011). Intensity Parameters as Damage Potential Descriptors of Earthquakes. Computational Methods in Structural Dynamics and Earthquake Engineering. Corfu: III ECCOMAS. ASCE. (2006). Minimum Design Loads for Building and Other Structures - ASCE/SEI 7-05. Reston, Virginia: American Society of Civil Engineers. ASCE. (2010). Minimum Design Loads for Buildings and Other Structures - ASCE/SEI 7-10. Reston, Virginia: American Society of Civil Engineers. Bracci, J. M., Reinhorn, A. M., & Mander, J. B. (1992). Seismic Resistance of Reinforced Concrete Frame Structures Designed Only for Gravity Loads. Buffalo: State University of New York. Caputo et al. (2012). GreDaSS (Greek Database of Seismogenic Sources). Retrieved August 01, 2015, from Earthquake Geology in Greece: http://eqgeogr.weebly.com/seismogenic- sources-in-greece.html Craig, R. R., & Kurdila, A. J. (2006). Fundamentals of Structural Dynamics (2nd ed.). New Jersey: John Wiley & Sons Inc. CSi Inc. (2014). CSi Analysis Reference Manual. California: Computers & Structures Inc. Eurocode 8. (2004). Design of structures for earthquake resistance - Part 1 BS EN 1998-1- 2004. London: BSi Standards Ltd. Flores, L. M. (2004). Performance of Existing Reinforced Concrete Columns under Bidirectional Shear and Axial Loading. Berkeley: University of California. Ger, J., & Cheng, F. Y. (2012). Seismic Design Aids for Nonlinear Pushover Analysis of Reinforced Concrete and Steel Bridges. CRC Press. Housner, G. W. (1952). Spectrum Intensities of Strong Motion Earthquakes. Proceeding os Symposium on Earthquake and Blunt Effects on Structures. EERI. Kalny, O. (2014). Hinge. Retrieved Aug 14, 2015, from CSi Knowledge Base: https://wiki.csiamerica.com/display/kb/Hinge Kappos, A. J., & Penelis, G. G. (1997). Earthquake-Resistant Concrete Structures. Abingdon: Taylor & Francis.
- 10. Konstantinos Myrtsis – MSc Civil Engineering 10 Krawinkler, H., & Seneviratna, G. D. (1997). Pros and Cons of a Pushover Analysis of Seismic Performance Evaluation. Engineering Structures, 20(4-6), 452-464. Mander, J. B., Pristley, M. N., & Park, R. (1998). Theoritical Stress-Strain Model For Confined Concrete. J.Struct. Eng(114), 1804-1826. Martinez-Rueda, J. E. (1996). Application of Passive Devices for the Retrofitting of Reinforced Concrete Structures. Proceeding of 11WCEE. Martinez-Rueda, J. E. (1998). Scaling Procedure for Natural Accelerograms Based on a System of Spectrum Intensity Scales. Earthquake Spectra, 14(1), 135-152. Martinez-Rueda, J. E. (2009). INARKUT: Seismic Inelastic Analysis of SDOF Systems using Runge-Kutta Method . (computer software). Martinez-Rueda, J. E. (2014). Scaling Procedure to Comply with Eurocode 8 Recommentations. University of Brighton. Martinez-Rueda, J. E., & Hamedi, F. (2014). Dual vs. Amplitude Scaling in Non-Linear Time-History Analysis. 10NCEE. Anchorage, Alaska. Matsumura, K. (1992). On the Intensity Measure of Strong Ground Motions Related to Structural Failures. Proceedings of 10WCEE, 1, pp. 375-380. National Institute of Stantands and Technology. (2011). Selecting and Scaling Earthquake Ground Motions for Perfoming Response-History Analyses. USA: US Department of Commerce. Park, Y. J., & Ang, A.-S. (1985). Mechanistic Sesmic Damage Model for Reinforced Concrete. Journal of Structural Engineering(111), 772-739. Reyes, J. C., & Kalkan, E. (2012). How Many Records Should be Used in an ASCE/SEI-7 Ground Motion Scaling Procedure. Earthquake Spectra, 28(1), 1223-1242. SHARE. (2012). The European Database of Seismogenic Faults. Retrieved August 01, 2015, from SHARE: http://diss.rm.ingv.it/share-edsf/index.html Shearer, P. M. (2009). Introduction to Seismology (2nd ed.). New York: Cambridge University Press. Statistics How To. (2015). Trimmed/Truncated Mean. Retrieved Aug 28, 2015, from Statistics How To: http://www.statisticshowto.com/trimmed-mean/ Tsaklidis, K. (2011). Effect of Size and Degree of Fitting to Design Spectrum of a Family of Scaled Natural Accelerograms on the Estimation of Inelastic Seismic Demands . University of Brighton. USGS. (2014). Magnitude / Intensity Comparison. Retrieved August 02, 2015, from U.S Geological Survey Website: http://earthquake.usgs.gov/learn/topics/mag_vs_int.php Villaverde, R. (2009). Fundamental Concepts of Earthquake Engineering. New York: CRC Press.
- 11. Konstantinos Myrtsis – MSc Civil Engineering 11 Whittaker, A. S., Hortascu, A., Baker, J. W., Bray, J., Grant, D. N., & Haselton, C. B. (2012). Selection and Scaling Earthquake Ground Motions for Performing Response-History Analyses. Lisboa: 15 WCEE.