IKPIR, the Institute of Structural Engineering, Earthquake Engineering and Construction IT was founded on 27.10.1971 as part of the Faculty of Architecture, Civil Engineering and Geodesy of the University of Ljubljana. Its original name was the Computing Centre of the Faculty, and it operated as an internal institute of the Faculty for the needs of its teaching, research and consulting work. In its early years the main tasks of this Centre were education and the development of urgently needed software for the fields of building and civil engineering.
In the autumn of 1980 the Computing Centre was renamed as the Institute of Structural Engineering, Earthquake Engineering and Construction IT, which was an expression of the main fields covered, since that time, from the teaching, research and consulting point of view. Over the last 25 years IKPIR has developed into the largest teaching and research unit at the Faculty, both according to the number of staff employed on a full-time or a part-time basis, and according to the number of completed research projects and published works.
The aim of this publication is to provide a brief description of the teaching work carried out at IKPIR, as well as a survey of the most important achievements in research and consulting work in the different fields of work of the Institute, and of the academic staff who have been involved in this work.
University of Ljubljana
3 university colleges
26 500 students
Faculty of Civil and Geodetic Engineering
Department od Civil Engineering
7 chairs andinstitutes
Institute of Structural Engineering, Earthquake Engineering and Construction IT
Apart from their regular teaching work, i.e. lecturing, tutorials and seminars in the fields of the statics and dynamics of structures, reinforced-concrete structures (partly), earthquake engineering and computing, as part of undergraduate and postgraduate curricula for degrees in civil engineering, the academic staff of IKPIR have acted as mentors to 20 Ph.D. students, 30 M.Sc. students, and 176 B.Sc. students, and as co-mentors to 85 B.Sc. students and 7 M.Sc. students.
The researchers at IKPIR have played an important part in the government-supported programme for the training of young researchers. They have acted as mentors to 27 young researchers who have not only started to make important contributions within various research organizations, but have also assumed important responsibilities in various fields of civil engineering.
Through its numerous seminars for practicing civil engineers (more than 30 since 1971 , as many as 2500 engineers have taken part in them), the staff of IKPIR have endeavoured to provide a rapid transfer of research results into the design processes of the construction industry. In this way they have made an important contribution towards the introduction of modern methods of structural analysis in the design of building and civil engineering structures.
RESEARCH AND DEVELOPMENT ACTIVITIES
The staff of the Institute of Structural Engineering, Earthquake Engineering and Construction IT perform their work mainly in three fields, which are recognized in its title and presented on the following pages.
In the field of structures, IKPIR's work involves research into methods for the design of structures, the development of computer programs and their introduction into practice, and design projects involving the fields of the non-linear analysis of structures and industrial processes.
In the field of earthquake engineering, the Institute has achieved internationally recognized status and awards for its work in the development of new methodologies for the aseismic design of building structures, bridges, and industrial structures. In Slovenia, the Institute has had a decisive effect on the raising of design standards, as well as on the introduction of adequate technical regulations in the field of earthquake engineering.
Over recent years, the ever more intensive use of the computer in research work has resulted in the research of the more general problems of the use of the computer in building and civil engineering. The field of construction information technology includes integrated construction, information delivery, and management of information technology .
Since 1971, a total of more than 120 important research and development projects have been carried out, and several hundred scientific and technical papers have been published in Slovenia and in other countries. More than 50 publications have been written.
Structures - Computer aided design of structures
In the early years of work of the Institute, members of IKPIR's staff were engaged in studies of then new methods for the analysis of structures, including the Finite Element Method. This made possible the introduction of the Finite Element Method into the regular curriculum, the development of the Institute's own computer programs, and the introduction of these and other structural analysis computer programs into the everyday practice of designers of building and civil engineering structures. It was at this time that general computer programs for the analysis of linear structures, slabs and high-rise structures were developed, as well as special computer programs for the analysis of building systems consisting of precast reinforced-concrete elements.
At the beginning of the 1980's, the development of computer graphics made possible the use of computers in those parts of the design process which could previously only have been performed using traditional methods. Methods for the computerized design of reinforcement were studied, and computer programs were developed which were able to produce reinforcement plans for precast elements, slabs, walls and frame structures. The results achieved by these programs could be used directly for the planning and management of production at bar-bending plants. Up-to-date graphic pre- and post-processors were added to the majority of existing computer programs. In the second half of the 1980's research work was begun into expert systems in the field of technical regulations.
As an extension of the previously carried out research into the design of reinforcement, at present possibilities for the robotized assembly of reinforcement are being investigated. The assembly processes are being studied by means of computer programs for the simulation of robotized processes, which will make possible a realistic assessment of the feasibility and costs of robotized systems.
IKPIR is involved in the TEMPUS and ESPRIT programs, financed by the European Union.
Structures - Non-linear numerical analysis
At the end of the 1980's, a number of research projects were begun at the Institute involving the non-linear analysis of structures and industrial processes. This has provided affirmation of the Institute's work in several new areas. As well as performing fundamental research into non-linear numerical procedures and the development of computer programs, the Institute also participates in the solving of complex practical engineering problems. Various non-linear numerical models have been developed, together with software for the non-linear analysis of reinforced-concrete structures, for the analysis of the dynamic interaction between structures and liquids, and for the non-linear, transient analysis of heat transfer and of thermo-mechanical problems (ranging from tools for the heat treatment of industrial products, to industrial semi-conductors). Apart from various non-linear models for the description of the mechanical behaviour of materials (e.g. the elasto-plastic model, the elasto-visco-plastic model, the realistic model for concrete, which takes into account cracks in tension and failure in compression), a model for rubberlike materials and elastomers has also been developed. A model for the description of the movement of landslides has been developed on the viscous flow formulation. A special thermo-mechanical model for the simulation of processes for the treatment of glass and plastics has also been derived. The availability of all these non-linear numerical models have made it possible to analyse a wide spectrum of tasks which either could not be solved by using standard linear methods or whose solutions would be insufficiently accurate.
At present a new model for the static and dynamic analysis of thin shells is being developed, which will, in comparison with presently known formulations, make possible more accurate analysis of thin shell structures with large displacements and rotations, and will also be applicable to the analysis of large plastic-laminate containers. Improvements are being made to the model for the realistic non-linear behaviour of reinforced-concrete, which will make this model suitable for the analysis of complex structures such as cooling towers, chimneys, large industrial buildings, bridges, etc. A start has been made to the development of a modern program for the computerized design of tunnels and deep excavations.
In this field, the Institute is involved in a number of international projects financed by the European Union within the framework of the TEMPUS, COPERNICUS and CEEPUS programs.
Earthquake engineering is a discipline which deals with the effects of earthquakes on buildings and other kinds of structures, including their equipment, and involves studies of the resistance of these structures to seismic loads. If problems in the field of earthquake engineering are to be adequately solved, then an interdisciplinary approach is needed. Most important is knowledge from the fields of the theory of structures and structural design, and the link with engineering seismology is a particularly strong one. Earthquakes produce non-linear cyclic deformations of structures, so good knowledge of the behaviour of materials and structures up to their limits of load-bearing capacity and deformability forms one of the most important elements of earthquake engineering. As a result, earthquake engineering is at the forefront among those disciplines which lead to further progress in the field of building structures.
Research in the field of earthquake engineering has been going on ever since IKPIR was first established. At first this research was limited to the elastic analysis of high-rise buildings. The result of this research was the development of the well-known computer program EAVEK, which is still today, in its updated and somewhat more sophisticated version, an irreplaceable tool when designing building structures. Later, research was extended to include the non-linear analysis of building structures, inelastic response spectra, the determination of seismic loads, energy-based methods, aseismic regulations, methodologies for aseismic design, the analysis and design of bridge structures, and computer tools for the support of aseismic design of structures.
Through their achievements, the researchers of IKPIR have become well-known in Slovenia, and have at the same time become involved in world-wide developments in earthquake engineering, so that the results of their research work are internationally recognized. This is proved by the numerous articles that have been published in international journals of high standing, by invitations to the position of visiting professor and lectures given at well-known foreign universities (including Stanford University, McMaster University at Hamilton, ETH of Zrich, Technion of Haifa, Tsinghua University of Peking), by membership of the editorial boards of a number of international journals (including Earthquake Engineering and Structural Dynamics, the Journal of Earthquake Engineering, Soil Dynamics and Earthquake Engineering) and in the scientific committees of international conferences, by membership of the working committees of international professional organizations and of international committees for standardization, by cooperation over many years in international research projects, including those financed by the U.S. - Slovenian Joint Board for Scientific and Technological Cooperation (joint projects with the University of California, Berkeley, with Stanford University, and with NIST) and by the European Union (projects within the framework of the INCO-COPERNICUS, COST and TEMPUS programs), as well as by numerous Slovenian and foreign awards (including the most important national award for research work). The international workshop entitled "Non-linear seismic analysis and design of reinforced-concrete buildings", which was organized by IKPIR together with Stanford University and took place at Bled in Slovenia in 1992, was a particularly resounding success. Members of the research group also carry out, apart from their fundamental research, applicative and developmental studies, and the results of this work are transferred into practice through the updating of technical regulations, seminars, and developmental projects, as well as through the work of young researchers and students.
Construction Information Technology
The goal of construction information technology is to provide computerized information management throughout the life-cycle of a building product.
Back in the days of large centralized computers, IKPIR produced high quality software for computer graphics, user interface design and data management. The consequence of the rapid development of information technology and the introduction of personal computers have been the introduction of languages C and C++, of object-orientated data-base, and of user-friendly interfaces. IKPIR was amongst the first in the field to take advantage of the object-orientated approach which turned out to be very suitable for structural and civil engineering problems. Computer integrated construction (CIC) was systematically researched at IKPIR during the period 1993-95 within the national research project "The computerized integrated design and construction of reinforced-concrete structures". IKPIR also participates in the work of the CIB working group on CIC. We have also been studying the computerization of building regulations, the electronic technical document management, for integrated information systems, and object-orientated data-bases.
In 1993, IKPIR was among the first in the field to start publishing on the Internet. IKPIR has prepared a number of frequently visited and read services, which were aimed at the international community of researchers and teachers. Together with the GI-ZRMK (Building Institute) and the Building Center of Slovenia, IKPIR set up the core of Slovenia's technical information system for building and civil engineering - TIGRA. The organization of an international workshop "Construction on the Information Highway" has also further affirmed the work of IKPIR in this field. IKPIR is also full partner in the European Union's ESPRIT project on concurrent engineering - ToCEE.
Ever since it was first established, the staff of IKPIR have endeavoured to achieve the transfer of research results into practice, into civil engineering design and consultancy work, and into the development of updated technical regulations for the fields of building and civil engineering (IKPIR is particularly active in the implementation of the new European standards for structures - Eurocodes - in Slovenia). Members of IKPIR's staff have also carried out several hundred complex studies, development projects, and consulting jobs. Listed below are some typical examples of this work.
Computer software for the design of building structures (1971-96)
This computer software, developed at IKPIR, is used by the majority of designers of building structures in Slovenia, and has been applied to the majority of Slovenia's more important buildings, built over this period.
Structural analysis of GORICA prefabricated structures (1971-80)
More than one hundred structural analyses were performed for structures built in all parts of the former Yugoslavia. A computer program developed at the Institute was used. The results of the program consisted of the internal forces, the stresses in the concrete and in the subsoil beneath the foundations, and the necessary reinforcement.
Residential tower-blocks, 12 to 22 storeys high, in the Knježevac Housing Estate in Belgrade (1976)
Designs were made of the load-bearing structure of these tower-blocks, using all available computer programs for the analysis of structures.
Structural analysis of the load-bearing structure of the arched bridge at Solkan, and of the supporting shuttering (1981-83)
Static and dynamic analyses were performed for the arched road bridge at Solkan.Computer programs developed at IKPIR were used for this design project, too.
Review of the design for the building structure of the National and University Library at Zagreb (1983 and 1987-90)
Designers at "Tehnika" and "Građevinski inštitut" of Zagreb had the task of designing the complex structure of the new library building in Zagreb. The experts of IKPIR performed reviews of the design as it progressed, and members of some of the Faculty's other chairs also participated in the case of certain parts of the structure. As the result of excellent cooperation between the designers and IKPIR's experts, who carried out numerous additional analyses, a number of mistakes were eliminated from the design, and several proposals for significant improvements to the structure were made.
Development of the SCT large-panel system (1986-87)
SCT, ZRMK (the Institute for Testing and Research in Materials and Structures), and IKPIR all participated in an extensive research and development project. The result of this work was the development of a large-panel system which can be used for the construction of buildings in regions of high seismicity. Blocks containing more than 1000 flats have been built using this system in Ljubljana.
Seismic analysis of the Reber Viaduct (1990)
In 1990, when adequate Slovenian technical regulations for the design of bridges in seismic regions were not yet available, a seismic design was carried out for two parallel reinforced-concrete viaducts, 600 m long, to be built on the motorway section between Malence and Šmarje Sap. In the design, the findings of the latest Slovenian and foreign research work were taken into account.
Probabilistic analysis of the seismic hazard at the location of the Krško Nuclear Power Plant (1991-94)
This was, from the technical and the organizational point of view, an exceptionally demanding project, which involved the reassessment, using the most up-to-date methods, of the seismic design parameters for the location of the Krško Nuclear Power Plant. This study, which was ordered by the Krško Nuclear Power Plant, was headed by IKPIR, taking into account very stringent quality assurance requirements, and lasted for four years. Also taking part in the project were seismologists and geologists from Slovenia and Croatia, as well as numerous foreign experts.
Implementation of the Eurocode 8/2 Standard (1994-95)
Taking into account the critical state, in Slovenia, of the technical regulations and standards dealing with the aseismic design of bridges, as well as the rapid building of such structures within Slovenia's new motorway construction program, it was necessary to establish, within the shortest possible time, the European pre-standard Eurocode 8/2, which deals with the design of bridges in seismic regions, for use in Slovenia. Within the framework of a research project, financed by DARS, the Company for Motorways in Slovenia, over the period 1994-95 a national application document, a translation of the pre-standard into Slovenian, and five test examples were prepared. The pre-standard and two of the test examples have been prepared in the form of hypertext . A handbook has been prepared, and two seminars for designers have been organized.
Numerical structural safety evaluation of the cooling-tower of block 5 (tower No. 4 of height 80 m ) of the Šoštanj Thermo-Electric Power Plant (1995)
The structural safety of the cooling-tower was analysed in order to determine the critical zones for repair of the structure on the basis of the actual geometry and condition of the structure. The structure was analysed as a spatial beam system, loaded by its own weight, wind and thermal loadings. The results of the analysis produced the basis for the design of adequate and urgently needed repair works to the cooling-tower.
Numerical non-linear analysis of the 150 m high chimney of block 4 of the Šoštanj Thermo-Electric Power Plant (1996)
The purpose of this project was to determine the reasons for the occurrence of cracks and the selection of an appropriate method of repair for the chimney. A transient, non-linear, thermo-mechanical analysis was performed using the software package BTHEV44, which was developed at IKPIR. This program package is based on the simultaneous solving of two systems of equations (the heat transfer equations, and the incremental equations of the mechanical equilibrium of deformable bodies) within selected time intervals. In the case of transient analysis, the thermal load was described by taking into account the changing temperature of the chimney, which simulated the operational gas temperature changes. On the external surface of the chimney, different temperatures were simulated corresponding winter and summer temperatures, partial insolation and partial shading. The mechanical loadings consisted of the chimney's own weight and wind.
IMPORTANT FUNCTIONS HELD AT THE UNIVERSITY
Rector of the University: E.Prelog
Dean of the Faculty: J.Duhovnik, P.Fajfar
Head of Department: J.Duhovnik
Member of the Slovenian Academy of Sciences and Arts: P.Fajfar
Professor Emeritus: E. Prelog
Associate Member of the Engineering Academy of Slovenia: F.B.Damjanić
Associate Member of the Croatian Academy of Technical Sciences: F.B.Damjanić
State awards for research work: P.Fajfar (2), M.Fischinger, E. Prelog, T.Vidic
Awards made by foreign universities: F.B.Damjanić, P.Fajfar (2)
Prešeren prizes for students at the University: M.Cuderman, M.Fischinger, P.Gašperšič, T.Vidic, D.Žlajpah, T.Cerovšek