PERFORMANCE BASED EVALUATION AND RISK ANALYSIS E. Mistakidis Dept. - PowerPoint PPT Presentation

COST C26: Urban Habitat Constructions under Catastrophic Events WG2: Earthquake resistance PERFORMANCE BASED EVALUATION AND RISK ANALYSIS E. Mistakidis Dept. of Civil Engineering, University of Thessaly, 38334 Volos, Greece R. Vacareanu Dept. of Reinforced Concrete, Technical University of Civil Engineering, 020396, Bucharest, Romania A. Kappos Laboratory of Reinforced Concrete Technology and Structures Dept of Civil Engineering, Aristotle University of Thessaloniki, Greece Naples, September 16-18 2010

Introduction This chapter of the general report of the activities of the action COST- C26 concerns the topics of :  performance based evaluation of structures  risk analysis  seismic vulnerability assessment. It is part of the activity developed within the Working Group 2 (WG2) of the Action, with the title " Earthquake resistance ". This activity is generally documented by the proceedings of the main events of the Action, i.e.  the workshop that took place in Prague in 2007,  the seminar organized in Malta in 2008, and  the final conference that was organized in Naples in 2010  interesting contributions that were given in the working group meetings of the Action are presented. All the presentations of the WG2 members are available on the web (http://www.civ.uth.gr/cost-c26/index.files/WG2.htm).

PERFORMANCE BASED STRUCTURAL EVALUATION AND DESIGN

Short state of the art Every seismic occasion reminds the need to improve the seismic performance of the built environment through the development of advanced procedures and guidelines. Such procedures have been termed Performance Based Seismic Engineering (PBSE) in the literature and can be applied :  for the design of new structures  for the evaluation of the seismic adequacy of the existing buildings stock. Early contributions :  capacity spectrum method (Freeman 1975,1987, Deierlein and Hsieh 1990)  acceleration-displacement response spectrum format (Mahaney et al 1993) These methods have application to low or midrise structures, in which the response is characterized by the fundamental mode of vibration. The reliability of these methods for structures in which higher modes of vibration are significant may not be adequate. Recent contributions :  the adaptive pushover method (Bracci et al. 1997, Elnashai 2000) the “N2”method ( Fajfar and Fischinger, 1988, Fajfar and Gašperšič , 1996)   the incremental response spectrum analysis (Aydinoglu 2003)  modal and multimodal methods (Chopra and Goel 2002, Chopra et al 2004, Sasaki et al 1998)  upper bound pushover analysis (Jan et al 2004)  A very detailed state of the art is contained in FEMA 440 (FEMA, 2005).

COST-C26 contribution  Mistakidis E., Apostolska-Petrusevska R., Dubina D., Graf W., Necevska-Cvetanovska G., Nogueiro P., Pannier S., Sickert J.-U., Simões da Silva L., Stratan A. & Terzic U. 2007. Typology of seismic motion and seismic engineering design, Proceedings of Workshop in Prague, March 2007.  Mandara A., Avossa A.M., Ferraioli M., Ramundo F. & Spina G. Performance-based seismic retrofit of masonry and R.C. buildings, Proceedings of Workshop in Prague, March 2007.  Pascu R. The performance based approach in seismic rehabilitation of Buildings, Proceedings of the International Symposium in Malta, October 2008 (Keynote lecture).  Lungu D., Arion C. & Calarasu E. Bucharest soil conditions and input ground motion for the structural performance analysisProceedings of the International Symposium in Malta, 23- 25 October 2008.  Apostolska, R., Necevska-Cvetanovska, G. & Cvetanovska, J. 2010. Seismic performance of RC building structures with masonry infill, Proceedings of the Final Conference in Naples, September 2010.  Ayala, A.G., Mendoza, M. & Apostolska, R. (2010). Development and validation of a procedure of seismic performance evaluation of structures, Proceedings of the Final Conference in Naples, September 2010.  Dogariu and Dubina Performance based evaluation of seismic retrofitting techniques, presentation during the meeting in Aveiro (http://www.civ.uth.gr/cost- c26/index.files/WG2.htm).  F. Mazzolani, A. Mandara, B. Faggiano, A. Formisano, A. Marzo, A robustness based method for the validation of seismic retrofit, presentation during the meeting in Aveiro (see http://www.civ.uth.gr/cost-c26/index.files/WG2.htm)

Mistakidis E., Apostolska-Petrusevska R., Dubina D., Graf W., Necevska-Cvetanovska G., Nogueiro P., Pannier S., Sickert J.-U., Simões da Silva L., Stratan A. & Terzic U. COST-C26 contribution 2007. Typology of seismic motion and seismic engineering design, Proceedings of Workshop in Prague, March 2007. The report contains two contributions related to performance based design.  The first concerns a study on the magnification of seismic action on short period structures . The study was performed using a nonlinear SDOF oscillator subjected to various ground motions recorded in Greece . In order to cover various structural typologies, different force-displacement models were used. The study compared the results of the various nonlinear analyses performed with the formulas given in FEMA356 for the estimation of the target displacement using the Displacement Coefficient Method (DCM). R=4 7 DCM, T2=0.4 6 MODEL-A PROPOSITION 5 4 d n /d e 3 2 1 0 0 1 2 3 4 5 6 7 8 9 10 Frequency ν

Mistakidis E., Apostolska-Petrusevska R., Dubina D., Graf W., Necevska-Cvetanovska G., Nogueiro P., Pannier S., Sickert J.-U., Simões da Silva L., Stratan A. & Terzic U. COST-C26 contribution 2007. Typology of seismic motion and seismic engineering design, Proceedings of Workshop in Prague, March 2007. In the second contribution, an extension of the performance based design procedure was presented that considered uncertainties through the notion of fuzzy analysis .  Informal and lexical uncertainties are described and quantified on the basis of fuzzy set theory with the aid of assessed intervals. In the field of seismic structural analysis, this framework gives the ability to treat deficits of information describing input variables, human mistakes and mistakes in fabrication, utilization and maintenance of structures, etc.  A simple application if presented in which the uncertainty in the input parameters affects the structural response .  A fuzzy capacity curve is obtained, which is afterwards combined with the seismic demand to obtain a fuzzy target point . H/V 0.400 0.400 0.400 0.300 0.300 0.300 Elastic Point 0.200 0.200 0.200 "Fuzzy" capacity curve 0.100 0.100 0.100 Displacement (m) 0.000 0.000 0.050 0.050 0.050 0.100 0.100 0.100 0.150 0.150 0.150 0.200 0.200 0.200

Mandara A., Avossa A.M., Ferraioli M., Ramundo F. & Spina G. Performance-based seismic retrofit of masonry and R.C. buildings, Proceedings of Workshop in Prague, COST-C26 contribution March 2007. Applications of performance based seismic retrofit for reinforced concrete and masonry buildings were presented. The R.C. frames were reinforced by eccentric steel braces and the masonry walls were strengthened by additional ties . All the analyses were carried out complying with the basic assumptions of the Performance Based Design. A damage-controlled nonlinear static procedure was defined to estimate maximum lateral displacement and plastic dissipated energy of RC frames, in order to keep damage indices in structural elements within tolerable limits at each performance level.

Pascu R. The performance based approach in seismic rehabilitation of Buildings, Proceedings of the International Symposium in Malta, October 2008 (Keynote COST-C26 contribution lecture). The paper presented a brief review and state of the art of Performance Based Seismic Design (PBSD) methods, focusing on the developments in the U.S. Moreover, the recent European Code EN 1998-3 and the Romanian Code P100-3 were presented and discussed. Some particular features of the PBSD were also discussed, as the demand assessment through incremental dynamic analysis , nonlinear response history analysis and nonlinear static procedures . Finally, an example of the rehabilitation design of a residential building in Bucharest was given.

Lungu D., Arion C. & Calarasu E. Bucharest soil conditions and input ground motion for the structural performance analysis. Proceedings of the International Symposium COST-C26 contribution in Malta, 23-25 October 2008.  The study concerned the Bucharest soil conditions and was based on the available data obtained from more than 400 boreholes .  The geological results, permit seismic microzonation of Bucharest to be used as a tool for urban planning and earthquake risk reduction . The results were correlated with shear wave velocity measurements in several locations having depth between 30 m and 200 m and with analysis of recorded strong earthquakes.