Precast Concrete Structures

Research focus

The Peer review has evaluated this group as Average

This research group is active in a variety of fields concerning the behavior of precast concrete structures. In particular, the following research topics are being investigated: a) Seismic behaviour of precast industrial buildings designed according to EC8: In seismic design the simplified method based on lateral equivalent forces relies on proper reducing factor, that simulate – on the whole - the effects of energy dissipation in the non-linear domain. So far these "behavior factors" have been quantified mainly by means of empirical approaches based on few analyses that cannot give precise and reliable values. A more accurate definition of the behavior factors is badly needed on the basis of rigorous analytical modelling, which should consider seismic actions as multi-variable random events. For such reasons, a fully probabilistic approach for the calibration of the behavior factors has been developed by comparing the results of simplified design approaches with those coming from nonlinear dynamic analyses simulating the actual structural behavior under seismic actions. The calibration of the behavior factors is performed by making reference to specific experimental tests. To this aim, an extensive experimental campaign has been planned and carried out at ELSA (European Laboratory for Structural Assessment) located in the Joint Research Center of Ispra – JRC, where pseudodynamic tests were performed on full-scale prototypes of precast RC frames. The objective of the tests is to characterize the seismic behavior of one-story industrial buildings. The nonlinear dynamic behavior of the frames in question is also modeled by introducing the cyclic degradation of the stiffness of the various members. The satisfactory agreement between the numerical and experimental results confirms the validity of the numerical model, as well as the soundness of the probabilistic calibration of the behavior factors for these structural systems. b) Vulnerability, assessment and retrofit of existing industrial buildings: The vulnerability and the assessment of existing precast industrial buildings is a topic of fundamental importance in Italy in view of the recently-introduced seismic Italian zoning code which has rather severe implications for the many industrial buildings built in Italy from the 70s to the 90s. At first the typologies of the existing precast industrial buildings are classified in accordance with five typical orders of connections: type 1 (roof-to-roof element), type 2 (roof element-toprimary/ secondary beam), type 3 (primary/secondary beam-to-column), type 4 (column-tofoundation) and type 5 (panel-to-beam/column). Secondly, an experimental characterization of each order of the connections is in progress, with the focus on the most important parameters affecting the vulnerability of the connections/ systems. Thirdly, after extended numerical analyses, proper methodologies, strategies and techniques for structural retrofitting will be proposed. c) Innovative solutions for precast industrial/residential buildings: In the domain of high-performance seismic-resisting precast concrete frame systems, within the PRESSS Project (PREcast Seismic Structural Systems) different techniques were investigated for the use of unbonded post-tensioned tendons with self-centering capabilities, in combination (when required) with seismic dampers for energy dissipation. New developments of these dry-joint connections are in progress for possible applications to precast residential buildings and precast concrete bridges. A comprehensive experimental campaign is under way at the University of Canterbury (New Zealand), where the tests are accompanied by refined numerical modeling and by the development of design provisions for these innovative structural systems. FURTHER DEVELOPMENTS Cyclic behavior of the connections between precast structural and non-structural elements: 140 As it is well known, the connections are a key element controlling the seismic behavior of precast structures, because - even if all the structural members (columns, beams and roof elements) are correctly designed according to the best seismic code - the actual reliability and safety of any precast structure depends on the correct performance of the connections, not only from the mechanical point of view, but also from the point of view of their location, number, ductility and strength resources. The commonly-used dry connections - consisting of mechanical devices connecting precast concrete elements – will be investigated both experimentally and numerically.

Dipartimento di afferenza

Dipartimento di Ingegneria Strutturale (DIS)

Docenti afferenti

Full Professors
Giandomenico Toniolo
Associate Professors
Fabio Biondini
Roberto Felicetti
Assistant Professors
Liberato Ferrara
Alessandro Palermo