Raziskovalna dejavnost na UL FGG

Research programmes

The following research programmes are active at the faculty:

E-civil engineering

Detailed data: SICRIS

Work of the group can be divided to four main fields and one horizontal field which together contribute to computer integrated construction in virtual organisation. The work aims at making the construction industry more efficient and competitive.

Topic 1: Numerical modeling of structures, computation and intelligence. Research has been done on numerical simulation of behavior of structures, structural elements and materials. Part of the work was related to development of procedures for simulation of damage and collapse of complex structures under extreme loading conditions.

Topic 2: Structured and semantic data. We developed a methodological framework for improvements to both BIM tools and schemata, which were studied using a conceptual process model and systems thinking. The results embrace the requirements for a BIM research methodology, with an example of methods and procedures and a multi-standpoint framework for developments.

Topic 3: Internet and communications. We were focusing on the computer-mediated communication together with the impact of the Web 2.0 trends and services on the communication and collaboration in engineering. The rationalle is in the fact that the uniqueness in the construction processes in many ways resembles the improvised nature of communication in social networks.

Topic 4: Engineering computing environments. The use of recently developed novel numerical methods (Topic 1) requires various computing environments. The evaluation of different technologies has been done. Specifically grid, cloud and sky computing technologies has been evaluated in the context of SMEs in AEC domain.

Topic 5: Knowledge transfer. Knowledge transfer of ICT in often a bigger problem than innovation and knowledge creation. Because the implementation of information communication technologies (ICT) in university study environment is important for the development of graduates’ competences and their initial preparation for entering labour market we studied this aspect of knowledge transfer.
The group remains internationally active. It contributed to a successful end of the Framework 6 Project I3CON. It succeeded in calls for proposals in the Leonardo da Vinci scheme. It continues the pan European collaboration in the post graduate Construction Informatics programs and the collaboration with the Stanford and Pecz Universities. Group leader had several invited and keynote lectures, he became the editor in chief of the ITcon Journal, member of the high level group for the evaluation of the Framework 7 IST program as a whole, chair of the high level group on the future of European academic networking. Members are also taking part in the review and scientific boards of conferences. In Slovenia the group continues the collaboration with the Engineeering Chamber, Gradbeni Vestnik Journal, leading companies such as Trimo, DARS, AMZS and DRSC. The group is also a partner in the Competence centre »Sustainable construction«.

Building Structures and Building Physics

Detailed data: SICRIS

Theme 1: Composite structures made of high strength steel and high strength concrete. Concretes and steels of up to the strength classes C80/95 and S690, respectively, are investigated together with composite structures and structural components made of these high performance materials

Theme 2: Prestressed concrete structures exposed to fire. The computational procedure of the nonlinear analysis of the response of reinforced concrete structures on simultaneous mechanical and fire loading will be extended also to prestressed structures. In addition to the hitherto considered regular nonlinearities of the material and the structure, the analysis will also take into account the slip at the contact between concrete and steel, as well as the influence of elevated temperature on the behaviour of the concrete and steel reinforcement.

Theme 3: High strength steel in seismic resistant frame structures. For the enhancement of seismic resistance at reasonable costs a combined use of mild and high strength steel is investigated – mild steel in dissipation zones and high strength steel outside these zones. By applying this approach (steel up to nominal yield stress 690 MPa) the following key aspects of steel frame robustness are to be fulfilled:

  • to enable development of plastic zones in preselected dissipative elements
  • to enable multiple routes for the transfer of forces and to ensure the redistribution of them
  • to provide sufficient overstrength to structural members that are not allowed to collapse at any cost.

Theme 4: Plated girders.Technical discussions within the ECCS/TC8/WG3, responsible for plated structures, revealed the necessity for additional research on moment-shear interaction in longitudinally stiffened web panels at intermediate supports of continuous plate girders. This problem is studied by means of numerical simulations, supported by full scale specimens.

Theme 5: Flame straightening of steel structures. The problems of flame straightening of welded steel structures are studied by means of test and primarily by numerical simulations. The main goal of the project is to develop (together with other partners in the RFCS project) recommendations for flame straightening.

Theme 6: Development of methods and tools for numerical modelling of materials and structures. New materials and new technical solutions require description of problems on different scales from nano, micro to macro level of the structure. The basic goal of the program in the field of numerical modelling is to bring together modern symbolic-numeric software tools and multi-scale modelling.

Theme 7: Renewable energy sources in buildings. Starting point of the work is harmonization of thermal and optical flows on the basis of the bioclimatic concept of building design. The conceptualization of innovative bioclimatic building elements with low energy use and supported by incorporation of renewable energy technologies comprises low-temperature large-surface system for heating and cooling.

Structural Mechanics

Detailed data: SICRIS

The research group was successful in publishing and promoting its results in high-quality peer-reviewed international journals and in disseminating new knowledge on national and international conferences. We wish only to point out here those works that seem to us to undoubtedly contribute to the “development of science”.

Tools for numerical non-linear static and/or dynamic analysis of structures. In 2010 we proposed a family of composite planar beam finite elements, where both slip and uplift at the contact between the beams is accounted for; a parallel work has been performed in the development of composite planar beam finite elements for the fire analysis of composite structures; a new energy-conserving time-integration scheme was employed in the optimizational dynamics with the view to be employed in the flexible robot design. We started solving the moving-boundary problems with meshless and level set methods which appear to be an effective substitute of the finite element methods in waste spreading analyses required for assessing the pollution danger of the nuclear power plants waste repositories. We have derived theoretically the sufficient conditions for convergence of finite elements AGQ6-I and AGQ6-II and show the effect of meshing on the rate of convergence. In the bilateral research project with the Technical University of Denmark in Lyngby, we developed a new mathematical model for water transport in porous hygroscopic material (e.g. wood). The similar research regarding new numerical tools will be ongoing in the next years. The finite elements derived here have been validated against analytical and experimental results from literature and thus provide tools for a reliable analysis of structural behaviour in various engineering problems, as shortly and selectively described in the sequel.

Composite structures in fire. It is essential to be able to predict behaviour of engineering structures in fire while considering both slip and uplift between the layers. Our numerical tools described above were in 2010 modified to include time-dependent temperature loading and realistic material laws that are capable of describing the behaviour of material during high temperature shocks. A systematic analyses have been performed to assess the effect of a number of parameters on composite, steel-concrete plates. A good insight into the behaviour of concrete in fire has been obtained, particularly with regard to moisture, pore pressure and temperature distributions and time-variations, along with the distributions of displacements, strains and stresses, which are typically needed in a structural design.

The waste spread from the nuclear power plants waste repositories (in co-operation with the NTF department of University of Ljubljana). In 2010 the NTF group started solving the moving-boundary problems with meshless and level set methods. These appear to be effective substitutes of the finite element methods in waste spread analyses when required in assessing the pollution danger from the nuclear power plants waste repositories.

Chemical Engineering

Detailed data: SICRIS

Results of research program contribute to the basic knowledge in the field of chemical engineering.

Research in the field of chemical engineering have contributed to the development of many new products in the slovenian companies, the competency of staff and improvement of quality, and comprehensive renovation of study program of Chemical Engineering at the University of Ljubljana.

Geoinformational Infrastructure

Detailed data: SICRIS

Majority of human activities are connected to physical space and numerous decisions are based on spatial data. Geodetic science, together with its professional fields, provides geoinformation infrastructure of the country and its society at the level of physical space. Mathematical and physical base of the geoinformation infrastructure is well-defined reference (coordinate) system. It is practically realized through geodetic land registers: land cadastre, topographic and cartographic system and urban infrastructure information system. On 1 January 2008, Slovenia adopted new coordinate system. According to “Real Estate Recording Act”, the use of the new coordinate system for all technical tasks regarding the real estate recording is obligatory. For all further activities relating to space, it will be is obligatory from 2010. The new coordinate system is the realization of the European Spatial Reference System (ESRS) at Slovenian territory. The ESRS consists of two separate coordinate systems: ETRS89 (European Terrestrial Reference System 1989) and EVRS (Euroepan Vertical Reference System). Both of them are realized at the level of pracictal use, still some further development is neccessary. The priority of the research programme is further development of the national coordinate system. In this regard, the care of the state and local communities for management of numerous spatial data bases is very important. This significant and permanent task is very demanding in respect of financial, temporal, organizational, and conceptual point of view.

Spatial data and data on land are the base for spatial planning and land use. Land is considered as the elementary source for human existence but its extent is limited. From this reason, land must not be seen as an isolated physical entity. On the abstract level (from the legal perspective), land represents a set of rights and regulations relating to its use. The extent and content of these rights and regulations had been changed in the human history, today they are introduced by different institutions with the aim of guiding suitable land management, spatial development. Suitable land policy and guidelines for sustainable development require monitoring of the space (spatial changes), and knowledge on the roles of institutions by land management procedures. Beside the physical and legal data on land, other spatial data are referring to the land (real property), which can be included in the spatial data analysis as well as in decision making procedures in the framework of advanced GIS technology. The importance of spatial data has to be particularly emphasized in the field of spatial planning, land policy and spatial development in general. Spatial data quality and suitable approach to their analysis are nowadays of crucial importance in the area of decision making for sustainable economic, social and environmental development of society.

Water Science and Geotechnics

Detailed data: SICRIS

In the field of hydraulic and hydrodynamics research, the work was focused on further development of our own 1D, 2D and 3D mathematical models for computations of flow and transport of pollutants in rivers, lakes and coastal seas. The model PCFLOW2D was accomplished with new boundary conditions and connected with 1D model PLAZ1D and 1D model IMPLI2009. With the combined models the computations of unsteady free surface flow over irregular terrain in sudden enlargements are now possible. The 3D model PCFLOW3D was completed into a fully 3D model which is capable to simulate flow in cases where horizontal and vertical velocities are of the same order of magnitude. In 2009, we focused to introducing hybrid modelling in the field of modelling of natural and man-made watercourses including all water management structures and hydro power plants, as hybrid modelling combines good properties of physical and mathematical models into a tool that can be used to solve complex, demanding and comprehensive problems in hydarulic practice.

In the research field of hydraulic engineering and hydrology, we actively executed the proposed research programme and so we performed field measurements in the experimental watersheds, analyses of available enviromental data in this two fields, and collaborated with field measurements at modelling of hydro power plants.

In the research field of sanitary engineering we continued the proposed work in all three fields: (1) mathematical modeling of ecosystems, (2) advanced techniques of waste-water treatment (WWT) and (3) theoretical hydraulics. On the basis of deterministic conceptual mathematical model WEST for simulation of urban drainage watershed with mixed sewerage and including WWT plant we have constructed a robust MM by induction. This model enables on-line real-time simulations and predictions. The model was built into big GIS relational base for transport and fate of priority pollutants according the Water framework directive (WFD). Within advanced oxydation processes (AOP) we investigated ultrasound and cavitation for decomposition of heavily degradable organic matter in WW. The results are statistically significant, but not quite repeatable. Pilot wastewater treatment plants are running for testing purification of brackish or heavily biodegradable municipal wastewater. Nutrients mass balances are established for the intermittent Lake Cerknica.

In the field of geotechnics, we focused research efforts into investigation of soil suction, especially of flysch landslide masses of the active Slano blato landslide, performing laboratory tests and field measurements of relevant parameters on a test plot on the landslide itself.

Earthquake Engineering

Detailed data: SICRIS

The research is aimed at obtaining new knowledge which will contribute to an increased seismic resistance of structures and their equipment, at transferring this knowledge to the designers and other stakeholders and thus contributing to the mitigation of consequences (prevention of casualties, decrease of material damage, and protection of cultural heritage) of future earthquakes. Reliable mathematical models will be developed which will be useful for complex analyses of important structures. On the other hand, simplified models appropriate for everyday practice will be proposed. Research is devoted mainly to the problems which have not been adequately solved worldwide and which are, at the same time, important for the application in Slovenia. Research involves studies on extending the applicability of the N2 method (asymmetric structures, the inclusion of the influence of higher modes of vibration, probabilistic analyses), studies on the influence of multi-layer facade elements and shear panels on the seismic response of frame structures, research related to the determination of the capacity of structural elements and whole structures, development of a macromodel with several springs for the analysis of reinforced concrete walls, and studies of connections in prefabricated industrial systems. Response of a bridge will be studied, which will be tested on a shaking table, and where innovative materials and details will be used. Research involves also studies of the improved technology for strengthening of bridge piers by using carbon fibers, studies on the prediction of seismic ground motion at the location of the facility, the development of methods which can quite reliably predict the response of structures with a very small number of analyses, and the development of load bearing laminated glass panels. In addition to the research oriented to structural aspects, research on the application of advanced materials for design of seismic resistant structures are also performed. The materials of our interest are self compacting concrete, fibre reinforced plastics and laminated glass. In the area of immovable cultural heritage, the low intrusive intervention techniques in heritage building aimed at increasing their capability to resist natural disasters and particularly earthquake actions are studied. The influence of an integral intervention in existing buildings including heritage ones (structural interventions, increase of energy performance, durability concern oriented actions) on the life time behaviour including life cycle cost assessment are investigated. Research is analytical, numerical and experimental. A collaboration with numerous research centres worldwide has been established. Young researchers are trained within the programme group. The results of the basic research are used in application and development projects and in research related to the updating of standards. The research results are transferred into practice in different ways.