ELSA - European Laboratory for Structural Assessment

About the lab

The core research activities of ELSA are developed in support of the standardization in construction and for assessing the physical vulnerability of critical structures.
The main facility of ELSA is a Reaction Wall unique in Europe by its size and capabilities, allowing tests of structures at full scale to assess their behaviour when exposed to earthquakes or other forms of cyclic loads. Work related to existing structures includes the development of techniques for their strengthening and/or repair that are validated by means of tests performed on representative models.
Another facility of ELSA is a large Hopkinson bar (HopLab) that allows dynamic testing of materials and structures subjected to extreme loads, simulating high strain rates representative of impact and explosion.

Featured projects (7)

The Joint Research Centre is offering transnational access to the ELSA Reaction Wall, within the Horizon Europe project ERIES (Engineering Research Infrastructures for European Synergies). This is a unique opportunity to have your experimental project fully financed. The ERIES project will cover the cost for the construction of the specimens, use of the laboratory, staff and equipment necessary for the experimental project, as well as travel and subsistence of users for preliminary meetings and for attending the tests. Two transnational access projects will be hosted at the ELSA Reaction Wall.
Fill the gap in the knowledge of seismic behaviour of the connections between precast concrete members. Pseudodynamic tests on a full-scale 3-storey precast concrete building, carried out at the European Laboratory for Structural Assessment (ELSA), Joint Research Centre (JRC) of the European Commission in Ispra.
Multi-hazard performance assessment of structural and non-structural components subjected to seismic and fire following earthquake Access to the ELSA Laboratory at the Joint Research Centre (Ispra, Italy) This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No.730900
European regulations for Seismic design do not include parts related to flat slab design. The Slab STRESS research project was launched as a basis for code development. A real scale flat slab building was designed and the response for gravity and lateral loads was studied experimentally.
The Joint Research Centre is opening the ELSA Reaction Wall to academia and research organisations, industry and SMEs. We invite cross-boundary proposals for projects to experiment, prototype and demonstrate ideas on the New European Bauhaus. The call for proposals is open until 16 January 2022. You can find more information in the link Priority topics may address, but are not limited to: • safe and green renovation of buildings • nanomaterials in buildings and construction (projects under this topic will use both the ELSA Reaction Wall and the JRC Nanobiotechnology Laboratory) • design and retrofit for resilience • safety of built infrastructure against multiple hazards, including climate change • new materials and technologies • sustainable construction • application of advanced testing methods. Prospective applicants are strongly encouraged to contact for clarifying matters concerning the technical capabilities of the facility, feasibility, cost, time schedule, etc.

Featured research (68)

The influence of cladding panels on the seismic behaviour of precast structures has for a long time been neglected, on the grounds that they were intended as non-structural elements and, as such, not expected to affect the global behaviour of the buildings. Increasing evidence from past earthquakes led to the conclusion that those assumptions did not held true and that new rules to account for the presence of claddings in the design of the buildings were badly needed, as well as rules for the design of their connections. The problem was addressed by means of the research project SAFECLADDING. The projects included an extensive experimental campaign, in which the interaction of the claddings with the prefabricated RC structure was studied in potentially all possible configurations. The evidence arising from those tests resulted into a set of guidelines, which in turn inspired the standard ISO22502:2020 for the simplified design of reinforced concrete structures with cladding panels and their connections. The experimental evidence that underpinned those design rules has been presented in an earlier companion paper for the case of vertical cladding panels only. Horizontal cladding panels are used more often because of their architectural flexibility, but their behaviour is more complex than that of vertical panels. Some design assumptions are often difficult to implement in practice, mainly due to their complex interaction. Therefore, what can be adopted for vertical panels may be difficult or even impossible to adopt for horizontal panels.
In flat-slab frames, which are typically designed as secondary seismic structures, the shear failure of the slab around the column (punching failure) is typically the governing failure mode which limits the deformation capacity and can potentially lead to a progressive collapse of the structure. Existing rules to predict the capacity of flat slab frames to resist imposed lateral displacements without losing the capability to bear gravity loads have been derived empirically from the results of cyclic tests on thin members. These rules account explicitly only for the ratio between acting gravity loads and resistance against concentric punching shear (so-called Gravity Shear Ratio). Recent rational models to estimate the deformation capacity of flat slabs show that other parameters can play a major role and predict a significant size effect (reduced deformation for thick slabs). In this paper, a closed-form expression to predict the deformation capacity of internal slab-column connections as a function of the main parameters is derived from the same model that has been used to develop the punching shear formulae for the second generation of Eurocode 2 for concrete structures. This expression is compared to an existing database of isolated internal slab-column connections showing fine accuracy and allowing to resolve the shortcomings of existing rules. In addition, the results of a testing programme on a full-scale flat-slab frame with two stories and 12 columns are described. The differences between measured interstorey drifts and local slab rotations influencing their capacity to resist shear forces are presented and discussed. With respect to the observed deformation capacities, similar values are obtained as in the isolated specimens and the predictions are confirmed for the internal columns, but significant differences are observed between internal, edge and corner slab-column connections. The effects of punching shear reinforcement and of integrity reinforcement (required according to Eurocode 2 to prevent progressive collapse after punching) are also discussed.
This paper presents an overview of the developments performed at the European Laboratory for Structural Assessment (ELSA) of the Joint Research Centre of European Commission concerning the new generation of servo-hydraulic real-time digital controller/acquisition system adopted in large scale experiments. The hardware architecture is based on EtherCAT® modules that guarantee a versatile and modular system easily adaptable to changing requirements (a typical situation experienced at ELSA with custom adapted non-standardized large scale structural experiments). Other fundamental features of this system are that all the analog signals are digitalized in the proximity of the transducers reducing noise-to-signal ratio (a great advantage for Pseudo-dynamic tests but in general for all experimentation), and all the different slave controllers communicate at each time sampling through a deterministic robust digital bus. In addition to the increasing computer performances, the developed simplified software architecture does offer a substantial improvement of control quality in terms of speed, safety, and accuracy compared with conventional/commercial systems.
Full-scale testing of a two-storey flat slab structure is reported, undertaken in the SlabSTRESS research project; the construction and testing were planned and carried out at the ELSA laboratory of the European Commission's Joint Research Centre. The dimensions are three bays by two, spans 4.5 and 5 m, slab thickness 0.2 m, interstorey height 3.2 m. Two different longitudinal reinforcement details were considered; welded studs shear reinforcement was provided only in the second floor slab. The testing program included seismic tests for service and ultimate actions, using the pseudodynamic technique with virtual walls. To this aim a building structure was designed with primary walls and the flat slab frame as secondary element. Cyclic loading tests followed up to ultimate drift capacity of the structure. The sequence of tests included strengthening of a set of damaged connections using bolted bars in holes drilled through the slab, followed by cyclic testing to failure. The instrumentation was provided for the global response and the connections with local rotations in the columns and slab; cracking around the columns was measured with through-crack sensors; a measurement system for internal forces and moments was included within the columns. The results show the response with deformations and damage for the different loading conditions up to failure. The results obtained on a full-scale structure extend and confirm the knowledge in the literature, mainly based on isolated connections and/or small-scale samples.

Lab head

Pierre Pegon
  • Joint Research Centre (JRC)
About Pierre Pegon
  • Current interest is focussed on the improvement of testing method at ELSA: 1) Fatigue testing using limit criteria formulated in displacement, force or both (application to embedded plate testing for ITER) 2) New implementation of the STEP method (Classical PsD method driven by an external software) with increment specified in displacements or force (application to the EQUFIRE project) 3) Improvement of the testing software for visualisation on the client side (test checking, telepresence, etc)

Members (9)

Paolo Negro
  • European Commission
Francisco Javier Molina
  • European Commission
Artur Pinto
  • European Commission
M. Peroni
  • European Commission
Georgios Tsionis
  • European Commission
Silvia L. Dimova
  • European Commission
Martin Poljansek
  • European Commission
Fabio Taucer
Fabio Taucer
  • Not confirmed yet

Alumni (5)

Samanta Robuschi
  • Chalmers University of Technology
Teresa Netti
  • Politecnico di Milano
Filip Manojlovski
  • Institute Of Earthquake Engineering And Engineering Seismology
Maria Chiara Caruso
Maria Chiara Caruso