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Projects / Programmes source: ARIS

Development of a practice-oriented method for the seismic risk assessment of building structures and equipment

Research activity

Code Science Field Subfield
2.01.04  Engineering sciences and technologies  Civil engineering  Earthquake engineering 

Code Science Field
T230  Technological sciences  Building construction 

Code Science Field
2.01  Engineering and Technology  Civil engineering 
Keywords
seismic risk, probabilistic seismic analysis, earthquake-resistant design, nonlinear analysis, buildings, reinforced concrete, masonry, floor spectra, tolerable risk
Evaluation (rules)
source: COBISS
Researchers (11)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  31961  PhD Marko Brozovič  Civil engineering  Beginner researcher  2011 - 2014  34 
2.  29480  PhD Daniel Celarec  Civil engineering  Junior researcher  2011 - 2012  27 
3.  18793  PhD Matjaž Dolšek  Civil engineering  Researcher  2011 - 2014  776 
4.  00025  PhD Peter Fajfar  Civil engineering  Head  2011 - 2014  869 
5.  33101  PhD Mirko Kosič  Civil engineering  Junior researcher  2011 - 2014  77 
6.  27532  PhD Maja Kreslin  Civil engineering  Researcher  2011 - 2012  142 
7.  05697  MSc Marjanca Lutman  Civil engineering  Technical associate  2011 - 2014  481 
8.  08745  PhD Iztok Peruš  Civil engineering  Researcher  2011 - 2014  283 
9.  01304  PhD Marko Polič  Psychology  Researcher  2011 - 2014  987 
10.  32691  PhD Jure Snoj  Civil engineering  Junior researcher in economics  2011 - 2014  72 
11.  00654  PhD Miha Tomaževič  Civil engineering  Researcher  2011 - 2014  743 
Organisations (3)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0581  University of Ljubljana, Faculty of Arts  Ljubljana  1627058  97,440 
2.  0792  University of Ljubljana, Faculty of Civil and Geodetic Engineering  Ljubljana  1626981  26,383 
3.  1502  Slovenian National Building and Civil Engineering Institute  Ljubljana  5866324000  10,361 
Abstract
Slovenia is located in the seismically active Mediterranean region. The consequences of strong earthquakes can be mitigated only by constructing earthquake-resistant structures and by strengthening of existing structures. The planned research is focused on a problem which has not yet been adequately solved worldwide and is important also for Slovenia, i.e. the development of a practice-oriented method for the estimation of seismic risk.  Research is fundamental and will contribute to the state of knowledge in several fields. The ultimate goal is development of a method which will enable a quantitative assessment of the seismic risk of building structures and their equipment, expressed in terms of the annual probability of collapse (or of the failure of equipment), or of the exceedance of a selected limit state. The method will be relatively simple in order to be useful for practice, but capable to take into account the most essential features of structural response. It will be based on extensions of the N2 method, which was developed at the University of Ljubljana and has been implemented in the Slovenian and European standard for earthquake-resistant structures Eurocode 8, and on the probabilistic methodology developed in the PEER Center, California. The main problems, for which new solutions have to be found or existing solutions have to be improved within the proposed project, are: determination of the deformation capacity of the elements and of the entire structure; obtaining quantitative data on aleatory and epistemic uncertainties related to typical reinforced concrete and masonry structures, extension of the N2 method with the option for determination of floor response spectra, facing  of technical data on risk with the perception of risk, and consideration of findings that the acceptable risk depends on the personal and social value judgments, and is therefore changeable. The research will be analytical and numerical, modern computer software and hardware will be used. Mathematical models will be verified with the results of experiments carried out in European and other international projects in domestic and major European laboratories. The simplified method will be verified by using the results of more accurate numerical methods. Established formal and informal links of the research group with leading research centers worldwide guarantee that the latest research achievements will be taken into account, and that the project will be coordinated with similar efforts around the world. Of particular importance are the partnership in the European research project SERIES (7th Framework Program), which involves 23 European institutions, including all the major experimental laboratories, and excellent cooperation with the Stanford University, where the majority of the work related to the development of the PEER probabilistic methodology has been done. The proposed project is closely associated with the national research program Earthquake Engineering. A collaboration of researchers at universities and research institutions is planned. A special quality of the project represents the collaboration between researchers in engineering and social sciences, which is crucial for practical implementation of earthquake mitigation measures, but is rare in Slovenia and also worldwide.The new method and new knowledge, which will be published in international and national literature, and will be disseminated to students, designers and other stakeholders, will contribute to rational decisions in design process and, ultimately, to increased seismic resistance of structures and their equipment at a reasonable cost, thereby reducing the number of casualties and damage to property and cultural heritage in future earthquakes.
Significance for science
Within the research project several results were obtained which contribute to the knowledge in the field of earthquake engineering. Partial results have already been published in the leading journals in the field of erathquake engineering. The practice-oriented nonlinear N2 method for seismic analysis of structures has been widely recognized and applied worldwide. It has been implemented in the European standard Eurocode 8. New results obtained on the extensions of the applicability of the method for probabilistic analyses represent important achievements. By combining the N2 method and the close-form equations for the assessment of the probability of exceedance of selected performance state of structures it was possible to formulate a method for quantitative assessment of the seismic risk of building structures and their equipment, expressed in terms of the annual probability of collapse (or of the failure of equipment), or of the exceedance of a selected limit state. The method is relatively simple in order to be useful for practice, but is reasonably accurate (considering all uncertainties related to seismic response of structzures and their equipment) since it is capable to take into account the most essential features of structural response. For the practical application of the method quantitative data on aleatory and epistemic uncertainties are needed, i.e. data on dispersions on the structural level. These date were determined for typical reinforced concrete (frames, walls and dual structures) and masonry buildings by extensive parametric studies. The cost of equipment is typically significantly greater than the cost of construction. Nevertheless, not enough attention is paid to its seismic resistance. As a further extension of the N2 method, a practice-oriented direct method for determining the floor spectra was developed, which allows the determination of floor acceleration spectra directly from the design spectrum for the construction and thereby significantly reduces the amount of the computational work. The inelastic behavior of the structure is taken into account, which could significantly reduce the maximum acceleration values in the floor spectra and thereby affect the rationality of the design. The proposed method is believed to be simpler and more accurate than existing methods and suitable for inclusion in the regulations. Determining the deformation capacity of reinforced concrete elements is largely based on the analysis of empirical data. In this field, the most important achievement is the preparation a publicly accessible database of experimentally obtained data for columns, beams and walls. The database is an extremely useful tool for further research on the capacity of reinforced concrete elements. We are not aware of any information on tolerable seismic risk for buildings, which would be obtained by interviewing professionals and laymen. The results obtained within the project therefore represent valuable information which will contribute to the selection of target values of risk .
Significance for the country
Seismic resistance of structures and their equipment is extremely important for the safety of the population in Slovenia, as well as for the protection of the material goods and of the cultural heritage. The results of research will, at the end, contribute to diminishing the number of casualties and material damage as well as to the protection of cultural heritage in the case of strong earthquakes. Young researchers have been trained to solve the most difficult technical problems, which will contribute to their successful independent work after the doctorate. The collaboration of researchers at the university and at a research institute, as well as between researchers in engineering and social sciences has produced important synergetic effects. Although the research was fundamental, the final result is a transparent design methodology that will be of practical significance. The developed method will enable obtaining quantitative information about seismic risk and will facilitate decisions related to earthquake resistant design of new buildings and strengthening of existing structures. An important result is also the contribution to code provisions. The existing N2 method is a constitutive part of the Eurocode 8 which is used as the Slovenian code for design of earthquake resistant structures. It is reasonably to assume that the extended N2 method, which has been developed within the research project, will be also, at least partly, implemented in Eurocode 8, first in the national document for the application in Slovenia, and then in the new version of Eurocode 8 standard. Eurocode 8 will be influenced also by the results obtained in research on the seismic capacity of reinforced concrete and masonry structures. The research results will have an impact on the research community, practicing engineers, professional organizations and committees, and code writing bodies. The research group is constantly involved in the organization of seminars for practicing engineers. The knowledge created is and will be incorporated in earthquake engineering courses at the University of Ljubljana and Univerity of Maribor. The results of investigations, in their final consequence, contribute to an increase of the seismic safety of new and existing structures, to more economical construction and to a better productivity and quality of seismic design. Collected information about existing and tolerable seismic risk, relevant for Slovenia, may, inter alia, contribute to the optimization of investments in earthquake resistant construction.
Most important scientific results Annual report 2011, 2012, 2013, final report, complete report on dLib.si
Most important socioeconomically and culturally relevant results Annual report 2011, 2012, 2013, final report, complete report on dLib.si
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