Projects / Programmes
Design of structures for tolerable seismic risk using non-linear methods of analysis
| 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 |
structural design, seismic risk, tolerated risk, nonlinear analysis, protection of built environement, buildings, bridges, cyclic experiment, web applications, high-throughput computing environment
Researchers (16)
Organisations (2)
Abstract
Slovenia is located in active seismic region with a moderate seismic hazard, where strong earthquakes may occur. Earthquakes with similar magnitude as that of L’Aquila earthquake, which caused over 300 losses of human lives, 1500 injured and 65000 homeless people, are expected in Slovenia. Experiences form recent earthquakes around the world show that the risk of loss of life and property due to seismic hazard is too high, if structures are not properly designed. This finding is not new, since different standards for the design of structures in seismic areas exist, but due to the complexity of the problem they involve many simplifications and assumptions. The usual design process does not prescribe the use of nonlinear methods of analysis, although it is assumed that the structure can be significantly damaged once subjected to design seismic action. In addition, seismic risk is not explicitly assessed in the design process. Therefore, we cannot claim that the current standards for seismic resistant design of structures control seismic risk to such an extent that would be acceptable for all types of structures and for all investors.
Development of nonlinear methods of analysis and powerful software for simulation of seismic response of structures offered a possibility to overcome shortcomings of the standards for earthquake resistant design of structures. The objective of the proposed project is therefore development of procedures and tools for design of structures for a tolerable level of seismic risk using the nonlinear methods of analysis. The innovative procedure for design of structures will represent a major step towards scientifically oriented design procedures employing high level of technology. The proposed design procedure will be iterative. Firstly, the initial structure will be defined whether on the basis of standards for seismic resistant design of buildings or on the basis of minimum requirements in conjunction with experiences of the structural engineer. The second step of design process will involve probabilistic seismic risk assessment of structure. If the seismic risk will be beyond the tolerable risk, structural configuration will be modified in accordance with developed guidelines and process of risk assessment will be repeated until the level of risk will be bellow the tolerable level, which will be defined according to established models for tolerable risk or according to the model which will be developed under the basic research project entitled Development of practice-oriented method for the seismic risk assessment of buildings structures and equipment (J24180, led by P.Fajfar).
If project will be approved, it will run in parallel with similar basic research project, which are under preparation at the most prestigious centres in the world that conduct research in the field of earthquake engineering (e.g. PEER Center - USA, Stanford University, EUCENTER - Italy). Well-established formal and informal collaboration with leading research centres worldwide guarantee that proposed research will be coordinated with similar research efforts around the world as well as with the research conducted within the European research project of the 7th Framework Programme in which member of research group are involved (SERIES, SAFECLADDING).
The project group will be similar to that of the project J2-0845 High-throughput computing environment for seismic risk assessment, which was estimated by the Slovenian Research Agency with the highest score. Thus, the members of project group will be researchers of research program Earthquake engineering and E-construction, as well as the researchers from the Slovenian National Building Institute, which have a lot of experience associated in performing the experiments. Under these circumstances it can be reasonably expected that the results of the proposed research will have high international impact and will significantly contribute to efficient mitigation of seismic risk.
Significance for science
The main result of the project is the method for the seismic design of buildings based on acceptable/tolerable risk. From a physical point of view, the proposed design approach is much more accurate than that used in the current design practice, where seismic risk is not even checked explicitly. This result of the project is significant from a scientific point of view, since it opens new research possibilities, as well as for the development of the profession, since it enables the design of structures based on physically justified facts. An important contribution for the development of the science field is an analytical method for the deaggregation of the probability of collapse. This method allows the determination of the level of seismic intensity which has the greatest impact on the probability of exceedance of a certain limit state. With the 3R method we introduced characteristic ground motions, which can be used for nonlinear dynamic analysis and allow the decision about the safety of the building which is defined by the probability of exceedance of a certain limit state. Since the number of characteristic ground motions is usually low (e.g. seven), a decision about the tolerability of the seismic risk of the investigated building can be made without performing a large number of simulations. Results show that decision-making based on few dynamic analyses is quite accurate, which was considered impossible, especially in earthquake engineering due to a large randomness of ground motions. To facilitate research and the dissemination of the 3R method we developed a web application, which automates selection of characteristic ground motions. We also upgraded the PBEE toolbox since software tools are a prerequisite for the implementation of the proposed design process. With the results of experiments on reinforced concrete columns we expanded the database of experimental results, which serves as a basis for the development of models for the prediction of the capacity of columns. The experiment was intentionally designed in such a way that it enabled investigations of the impact of uncertainty in construction. We therefore tested 12 nominally equal columns that were made by different companies. Results showed a large dispersion, especially for ultimate rotations. A detail of the stirrups had the largest negative impact on the ultimate rotation. There are very few similar experiments addressing the impact of the quality of construction worldwide. We expect that the project results will allow the implementation of new design processes, especially by enabling decision-making based on information, which is understandable to a wide society and not just to engineers. The dissemination of high-quality information about seismic risk already in the stage of design can significantly contribute to strengthening the resilience of society against extreme natural phenomena, as well as to the development of some fields of social sciences.
Significance for the country
Basic research project entitled Design of structures for tolerable seismic risk using non-linear methods of analysis contributed results which are important for the development of Slovenia in different fields: Development of methods and tools for the risk-based design of new and existing structures: The new design method is based on nonlinear analysis. Therefore, it is no longer required to take into account several assumptions, which are necessary with the conventional design method, which takes into account the results of linear elastic analysis. A physically specified design will also contribute to strengthening the resilience of society to extreme natural phenomena. The method is developed to such an extent that it can be used in practice, for example, for important technological buildings, where investment depends primarily on the equipment or where the consequences due to collapse are very large. The importance for the development of standards for the design of buildings in seismic areas: Slovenia is located in a seismic zone, where strong earthquakes can occur. It is therefore necessary to design all buildings to be earthquake resistant. Current standards allow that buildings can be damaged during strong earthquakes. The standard also states that the achievement of the goals of the standard can be measured only in probabilistic terms, but it does not specify the methods and procedures by which designers could inform stakeholders regarding the risk of damage or loss of functionality or even collapse. The new design method solves this shortcoming. The results of the project will therefore contribute to the development of new standards for design of buildings in seismic areas. Transfer of knowledge into practice, the development of new services on the market: The knowledge we have gained in the project was transferred into practice. The results of the project were used directly in the development of guidelines for the risk-targeted design of the house JUB Home. Part of the results of the project contributed to the development of a new service for the Krško nuclear power plant, which needed a seismic vulnerability study of a building within the plant. This analysis is part of an upgrade of safety of the power plant operation due to the accident in Fukushima. Žiga Šebenik, who was a key developer for web applications, was employed by CELTRA. Development of postgraduate education, mentoring doctoral students: The project results will be included in the curriculum of doctoral courses (e.g. Reliability of structures with application in earthquake engineering (Doctoral study programme Built Environment), Seismology and Earthquake Engineering (Interdisciplinary doctoral programme Environmental Protection)). This will enable a systematic education of students, who are interested in the field of earthquake engineering. Web applications and the extended software tool PBEE Toolbox enable new research. Additionally, the experimental results are accessible to other researchers. Promotion of Slovenia in the world: During the project we organized several events in the international area (mini symposium at the international conferences COMPDYN and VEESD, a special section on the World Conference on Earthquake Engineering 16WCEE) and a one-day workshop at Stanford University, where we presented the results of the project. In addition, we have published several research articles in prestigious international journals or international conferences. Participation in the application for European and other projects: The project results directly or indirectly contributed to integration into international consortia for the application of research projects. During the project we participated in four project applications. We have been successful with two applications: NEWREBAR (Research Fund Coal and Steel) and XP RESILIENCE (H2020, MSCA-ITN-2016). The results of the project will also be upgraded or used in the two new European projects.
Most important scientific results
Annual report
2013,
2014,
2015,
final report
Most important socioeconomically and culturally relevant results
Annual report
2013,
2014,
2015,
final report
