Objective
For industrial and economical purposes, it is very important to improve knowledge of the behaviour of the connections between members of a structure in order to :
be able to control the level of semi-rigidity, by developing practical analytical tools using realistic connection behaviour;
determine the amount of savings that can be achieved by using semi-rigid connections and simplifying accordingly the detailing of the connections;
gain a better estimate of the level of safety and provide information for a realistic determination of partial safety factors;
estimate the energy dissipation in the case of seismic loading and improve seismic design.
From the scientific point of view, the aim is to fill the gap between the levels of accuracy that are now reached for member behaviour on one hand and for connection behaviour on the other hand. So far as the whole response of the structure is concerned, the influence of connection behaviour is as important as member behaviour. Furthermore, in case of seismic loading, any damage in the connection is much more important than any damage in the adjacent members. In order to recognise the importance of connection behaviour, new concepts of structural analysis have to be developed.
The materials concerned are : steel, reinforced and prestressed concrete, timber, composite steel-concrete, polymeric composites and any novel combinations that could appear in the near future.
All the connections used in civil engineering structures are concerned :
welds, bolts, pins, rivets and screws for steel structures;
metal or timber connectors (nails, bolts, plates) for timber structures;
mechanical connectors and cast-on-site concrete for concrete structures;
steel fasteners and rebars for composite constructions.
adhesives, etc.
Current status.
The first meeting of the Management Committee, at which 12 states were represented, took place during May 1991.
At present time of writing (Dec 1996), 23 states participate in the Action (the last being Norway in September). The EC is participating in this Action through the ELSA laboratory (European Laboratory for Structural Assessment) of the JRC in Ispra (I), the University of Civil Engineering and Geodesy in Sofia (BG) joined the Action in the beginning of 1993 and the Technical University of Timisoara (RO) joined the Action in the beginning of 1996.
An inventory of experimental results and analytical tools in each participating country has been updated for all materials and types of connections used in civil engineering. Main divisions are :
connections in concrete structures :
connections in steel structures;
connections in composite steel-concrete structures;
connections in timber structures;
connections in polymeric composite structures.
In order to give the most clearly focused, efficient and effective organisation, the Management Committee set up Working Sub-Groups, in which the specific characteristics of each material are considered, although still within the context of the whole Action.
Subgroups are :
WG 1 Connections in reinforced and prestressed concrete structures
WG 2 Connections in steel structures and in composite steel-concrete structures
WG 3 Connections in timber structures
WG 4 Databases for collection of results
WG 5 Seismic action
WG 6 Numerical methods for behaviour analysis and simulation
WG 7 Connections in polymeric composite structures
The sub-groups 4, 5 and 6 are common to all materials.
The atmosphere between participants shows great enthusiasm and the response is very positive.
Each of the participants sees the opportunity to expand its base of knowledge. This initiative has also created a true multi-material integration.
During the period 1995-1996, the project has focused on all the aspects of semi-rigid connections :
Type of loading :
Static loading, which is investigated to evaluate the level of loading at the typical values in service and ultimate limit state of the whole structure;
Dynamic loading, which is investigated for a better knowledge of the seismic response.
Type of works :
Experimental works on isolated joints, substructures and whole structures;
Theoretical works;
Numerical works (simulation);
Database organisation for model calibration.
Work planned
The future work is still focused on two powerful ideas : classification and component method. Classification is a very powerful tool in practice since it allows the engineer to choose the best design correctly and rapidly. Regarding component method, it is now recognised as a very efficient way to predict connection behaviour for all types of material. It is a form of finite element method for structural analysis, specially adapted for connection problems. Theoretical research has to be done regarding interaction effects between components.
The individual components have to be investigated, for example in a form of catalogue for easy use in a database format. Furthermore the component method is fully relevant for the identification of dissipative zone in structural systems subjected to seismic loading.
It has been decided to press strongly the use of computer network facilities, especially for the exchange of data. Much work has to be done to get the relevant database format.
Programme(s)
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Data not availableCoordinator
4000 Liège
Belgium
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Participants (30)
Warszawa
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80815 Bebek - Istanbul
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1050 Bruxelles
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41296 Goeteborg
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41296 Goeteborg
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EC1V 0HB London
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2970 Horsholm
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DUBLIN 9
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1015 Lausanne
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21020 Ispra
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11000 Belgrade
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28071 Madrid
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80626 Istanbul
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22100 Lund
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221 00 Lund
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75231 Paris
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52074 Aachen
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2600 AA Delft
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2600 GA Delft
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33101 Tampere
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1521 Budapest
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28006 Madrid
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6020 Innsbruck
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4000 Liege
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9052 Zwijnaarde
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Sofia
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62000 Maribor
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NG7 2RD Nottingham
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Fisciano - Salerno
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02200 Espoo
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