Cyber-physical testing of civil engineering structures at the ELSA laboratory

Abstract

The European Laboratory for Structural Assessment performs tests of full-size specimens of civil engineering structures and contributes to the scientific knowledge on the behaviour of different structural typologies. Many of the testing campaigns are oriented to the improvement of design standards such as the Eurocode8, which is the European standard for seismic design of structures. The classic step-by-step Pseudo-dynamic (PsD) testing method is well suited for such huge specimens and is relatively easy to implement, including the case of substructuring, but imposes a very low execution speed of the test. A substantial improvement is introduced by the continuous PsD method that allows for a faster execution of the test and improves the quality of the results by making a more effective use of the measurements. This paper briefly reports on some examples of application of the classic method, such as bi-directional PsD tests on a real-size multi-storey building by using up to nine DoFs and twelve actuators, where sophisticated geometric and static on-line transformations of variables between the equation of motion and the controllers were required. As a second example, substructuring techniques developed within the PsD method have proved to be very useful for obtaining the seismic response of large structures, e.g. bridges. In such case, a testing set-up is devised in which the reduced part of the structure that suffers the largest damage (some of the piers) is the actual specimen whereas the rest of the structure (the deck and the remaining piers) is numerically substructured. Finally, another two examples refer to tests performed with the continuous PsD method on a new-design precast 3-storey building and on a 3-storey reinforced concrete building retrofitted with shear infill walls.