Influence of different mechanical column-foundation connection devices on the seismic behaviour of precast structures

Abstract

Dry-assembled precast concrete frame structures are typically made with dowel beam-to-column connections, which allow relative rotation along the beam direction. In the orthogonal direction the rotation of the beam is prevented but again the connections of the superimposed floor elements allow for relative rotation. All the ductility and energy dissipation demand in case of seismic action is therefore concentrated at the base of cantilever columns. Hence, the column-to-foundation connection plays a key role on the seismic performance of such structures. Mechanical connection devices, even if correctly designed for what concerns resistance, may affect the behaviour of the whole joint modifying the ductility capacity of the columns and their energy dissipation properties. An experimental campaign on different mechanical connection devices has been performed at Politecnico di Milano within the Safecast project (European programme FP7-SME-2007-2, Grant agreement No. 218417, 2009). The results of cyclic tests on full scale structural sub-assembly specimens are presented. Design rules are suggested for each of the tested connections on the basis of the experimental observations, and numerical analyses have been performed with hysteretic parameters calibrated on the experimental loops. The seismic performance of structures provided with those connections is investigated through a case study on a multi-storey precast building prototype, which has also been subject to full-scale pseudo-dynamic testing within the same research project at the European Laboratory of Structural Assessment of the Joint Research Centre of the European Commission. The comparison of the results from the structure provided with the different studied connections clearly highlights how some solutions may lead to both reduction of ductility capacity and dissipation of energy, increasing the expected structural damage and the seismic risk

Assessment of a capacity spectrum seismic design approach against cyclic and seismic experiments on full‐scale precast RC structures

“…The various hysteretic shapes are reported in Figure 4 (1 example case for every structural type). Details on the geometrical/mechanical properties of the specimens are not presented in this paper for the sake of brevity, while exhaustive information can be found in the above‐cited referenced papers . The corresponding EVD curves shown in Figure 5 (1 example case for every structural type) are evaluated based on the EVD vectors associated to approaches (i) and (ii).…”

“…Details on the geometrical/mechanical properties of the specimens are not presented in this paper for the sake of brevity, while exhaustive information can be found in the above-cited referenced papers. [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] The corresponding EVD curves shown in Figure 5 (1 example case for every structural type) are evaluated based on the EVD vectors associated to approaches (i) and (ii). Each point of the EVD vectors is evaluated by considering the mean value of the EVD factors of the 3 cycles associated to a determined imposed displacement.…”

Evaluation of out‐of‐plane seismic performance of column‐to‐column precast concrete cladding panels in one‐storey industrial buildings

“…The structural layout of the precast concrete structures considered herein, typical of industrial and commercial buildings, is composed of cantilever columns pin‐connected to prestressed RC beams spanning in one direction, which support prestressed concrete roof elements spanning in the transverse direction. The columns are embedded in a grouted socket left in the footing or connected to the foundation by means of mechanical devices or grouted sleeves . Industrial and commercial precast concrete buildings are typically characterized by higher interstorey height and higher roof flexibility compared to RC buildings.…”

End support connection of precast roof elements by bolted steel angles

“…Cyclic and pseudo‐dynamic tests on full‐scale prototypes of dry‐assembled structures with steel angle floor‐to‐beam connections were carried out in the framework of the Precast Structures EC8 (Growth) EU‐funded research project . Within the Safecast EU‐funded research project, pseudo‐dynamic tests were performed on a multistorey full‐scale prototype where direct dowel connections were used to connect the floor elements to the supporting beam . The cited experimental campaigns were focused on the overall seismic behavior of the structure.…”