The research team is very active in the application of the research results. The knowledge has been applied in the case of many specific projects. However, a single application is typically limited to only one or few structures. When a standard (in particular European standard) is improved, the benefit is multiplied many times. Therefore, we consider the continuous active participation of the research team members in the development of Eurocodes (in particular EC8 – Design of seismic resistant structures) and in the implementation of Eurocodes in Slovenia as one of the key results. We shall stress once again that Slovenia was the first country which adopted Eurocodes standards as a National code. The research team importantly contributed to this. Based on this experience, several members were invited to participate at the development of the new versions of Eurocodes. On the highest level, are the representatives of Slovenia in: - CEN/TC250/SC8 - Design of earthquake resistant structures (Peter Fajfar) and - CEN/TC 250/SC 11 – Structural Glass, which is the newest part of Eurocodes (Roko Žarnić) Several members are active in project teams, which are involved in development of the new versions of standards: CEN/TC250/SC8/PT1 (Matjaž Dolšek) CEN/TC250/SC8/PT3 (Tatjana Isaković) and in research working groups, in support of further developments of standards: CEN/TC250/SC8/WG2 (Roko Žarnić) CEN/TC250/SC8/WG4 (Peter Fajfar) CEN/TC250/SC8/TG1 (Peter Fajfar) CEN/TC250/SC6/WG1 (Vlatko Bosiljkov) Tatjana Isaković is the Chairman of the SIST Technical Committee for structures. In 2017 the Slovenian representatives were particularly active and successful. Based on their proposal the following important improvements have been incorporated into the new versions of Eurocodes (additional partial description of these contributions is given in Chapter 3): - EC8-1: Extended N2 method for inelastic analysis, which considers the contribution of the higher modes along the height of the building and the contribution of torsion (originally published in 2012, COBISS 5591649); - EC8-1: Simplified reliability-based verification format (M. Dolšek, M. Kosič, J. Žižmond, N. Lazar-Sinković, Development of Eurocode 8 - proposal for ANNEX F – Informative, COBISS.SI-ID 8273761); - EC8-1: Procedure to evaluate story response spectra (V. Vukobratović, P. Fajfar, Code-oriented floor acceleration spectra for building structures. Bulletin of earthquake engineering, COBISS.SI-ID 7896673); - EC8-3: T. Isaković included several modifications of the EC8-3 - Seismic Assessment of Existing Structures (M/515 for the development of 2nd generation of EN Eurocodes CEN/TC 250; Project CEN TC250 PT3, COBISS 8336993); - Amendment of masonry chapter of EC8 (S. Lu, K. Beyer, V. Bosiljkov, et.al.: Amendment of masonry chapter of Eurocode 8 : paper No. 4746, 16th World Conference on Earthquake Engineering; COBISS 7984993).
F.31 Development of standards
Seismic safety of bridges is typically less investigated than seismic safety of buildings. Therefore the methods for seismic analysis of bridges are still not well established due to the limited research. However, the adequate seismic response of bridges is a decisive factor for seismic resilience of the society in the case of catastrophic earthquakes. Two alternative approaches for the design of R/C bridges are compared in this work, namely the traditional Strength Based Design (SBD) and the Direct Displacement Based Design (DDBD). It is found that these two methods give the same results when the same set of assumptions is employed. These assumptions are (a) the yield curvature (displacement) is nearly invariant for the chosen type of steel and geometry of the critical cross-section, (b) the equivalent pre-yielding stiffness is strongly correlated to the strength, and (c) the equal displacement rule is applied in both cases. The basic assumptions and properties behind the non-linear pushover-based methods, which are included in modern design codes, are reviewed and some specifics related to their use for the analysis of bridges are presented and briefly discussed. Research was also conducted with the purpose of establishment a Multi-Criteria Decision Model, to be used in decision-making when refurbishment priorities within a group of passes are established; with the purpose of selecting the optimum set of passes to be refurbished (Kušar in Šelih, 2017; COBISS 8129889)
F.17 Transfer of existing technologies, know-how, methods and procedures into practice
COBISS.SI-ID: 8103009Precast buildings represent a considerable part of industrial and commercial infrastructure in Europe. While tenths of millions of square meters of precast buildings are built each year, the behaviour of the crucial element determining their seismic safety (beam-column dowel connection) was purely understood. These connections were frequently designed by (inadequate) feeling. The potential losses in the case of the strong earthquakes are therefore large. Two types of the failure mechanism of dowel connections are possible: (a) local failure, characterized by the simultaneous yielding of the dowel and crushing of the surrounding concrete; and (b) global failure, characterized by spalling of the concrete between the dowel and the edge of the column or the beam. The strength corresponding to these two types of failure were estimated using different procedures available in the literature and it was compared with experimental results. These procedures provide significantly different accuracy and reliability. In particular, the strength corresponding to the local failure is estimated quite precisely, while the strength corresponding to the global failure is typically considerably underestimated. Therefore, a new procedure for the estimation of the global failure was proposed and described. This procedure, based on the strut-and-tie model, grossly improves the reliability and economy of the design.
F.17 Transfer of existing technologies, know-how, methods and procedures into practice
COBISS.SI-ID: 8247649KEYS is an initiative for young scientists from countries in Africa and from Germany to enhance their skills in innovative research in the field of cement and concrete construction technology. It targets young postgraduate and young postdoctoral scientists and offers the unique opportunity to network with international high profile researchers and industry representatives. It also fosters networking of young scientists with peers in an international forum that promotes their role as future decision makers. Violeta Bokan Bosiljkov was invited to give lecture at the 3rd KEYS Symposium in Johannesburg, South Africa. She decided to focus on self-compacting concrete technology in Slovenia, which was predominantly developed in framework of the research programme Earthquake Engineering and later transferred to Slovenian construction sector. Applications of the technology for strengthening of civil engineering structures, such as bridges and viaducts, and transfer of technology to lime-based grouts and mortars for strengthening of cultural heritage buildings in order to increase their earthquake resistance were important part of her presentation.
F.05 Ability to launch new technological development cycle
COBISS.SI-ID: 8109409