Performance of Innovative Mechanical Connections in Precast Buildings Structures under Seismic Conditions
SAFECAST is a project financed under the 7th Framework Programme's Research for Small and Medium Enterprises (SME) Associations action. The project emerges from two previous research projects, the ECOLEADER and the PRECAST EC8 project, respectively. Both these projects dealt with the seismic behaviour and ductility capacity of precast concrete structures compared to cast-in-situ concrete structures. The outcome from both ECOLEADER and PRECAST EC8 confirmed that precast frames and buildings can exhibit ductile behaviour comparable to cast- in-situ structures. However, it was clear from the findings that the deformability of the floor system, and in particular the actual design of the connections between the floor/deck system and the vertical columns, was not fully understood and therefore difficult to model correctly for the numerical studies used in design of precast buildings structures.
The lack of an in-depth understanding of the seismic behaviour and ductility of precast concrete structures makes it difficult to utilize the beneficial ductility these structures can exhibit during an earthquake, if properly built. The limitations are mainly related to a lack of verified standardised floor system - column connections, and adequate and reliable numerical models for these connections to be used in design. Hence, SAFECAST has been established to address these current limitations, and to bring the seismic design of precast concrete structures in line with that of cast-in-situ concrete structures.
The main objectives of the project will be to fill the gap in the knowledge of seismic behaviour of precast pre-stressed structures, with specific reference to connections, deformability and interaction between precast and cast-in-situ elements. Further, the project aims to develop adequate, reliable and verified numerical tools to be used in design, and finally, to codify new criteria for the design of precast structures in seismic regions exploiting the properties of connection devices.
To address the objectives of the study, a series of monotonic, cyclic and shaking-table tests on connection devices, joints and subassemblies will be carried out. The technical solutions emerging from these tests will be applied in full scale structures, both single-storey and multi-storey frame structures, that will be verified in a large-scale pseudo-dynamic testing campaign.
The connection devices, joints and subassemblies tests, as well as the large scale pseudo-dynamic tests, will be simulated numerically in order to verify adequate numerical models for the various connections used in the test campaign.