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SAFECAST

Performance of Innovative Mechanical Connections in Precast Buildings Structures under Seismic Conditions

Background

SAFECAST is a project financed under the 7th Framework Programme\u2019s 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.

Rationale

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.

Objectives

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.

Method

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.

Scientific Publications


Design Guidelines for Connections of Precast Structures under Seismic Actions

Design Guidelines for Connections of Precast Structures under Seismic Actions

This document represents a set of practical guidelines for the design of the mechanical connections in precast elements under seismic actions. As a final outcome of the project SAFECAST, the document covers all the types of connections which were studied, experimentally as well as numerically, as a part of the project. However, by integrating the knowledge acquired during the project with the general state-of-the-art knowledge existing in the literature, the guidelines were extended to a potentially exhaustive set of connection typologies. Guidelines are also provided for defining the actions to be used in design. These guidelines can be used as a reference for designing the connections of precast structures under seismic actions whenever neither specific norms nor mandatory provisions exist. The guidelines do not cover the specific case of the connections of cladding elements, a problem which might deserve a specific study and might be the objective of a future research project.

Download the report (2.6MB)



October 5-7, 2009

International Workshop

Seismic performance of precast structures

A collaborative work of Structural and Earthquake Eng. Lab. Istanbul, Turkey and ELSA.

Ongoing Research

In the framework of the Project Performance of Innovative Mechanical Connections in Precast Building Structures Under Seismic Conditions (SAFECAST), a complete full-scale three-storey precast building is being subjected to the maximum earthquake for which it has been designed (0.3 g peak ground acceleration).

The building is being tested in different structural configurations, to throw light onto the behaviour of different types of connections (traditional as well as innovative).

A first test was conducted on the building connected to two shear walls.

In a second test, the shear walls were disconnected from the structure, to test the building in its most typical configuration (standard connections). The building behaved as expected, however, it suffered large deformations (more than 20 cm on top).

Further tests are expected, in which the advantages of the new connections developed as a part of the project will be explored.

The results of the tests will be used to calibrate adequate numerical models, which in turn will be used to derive practical design guidelines.

Structure PGA View
Test 1 - Walls 0.15g View
Test 1 - Walls 0.30g View
Test 2 - Hinged 0.15g View
Test 2 - Hinged 0.30g View

Framework

The Project is part of the 7th Framework Programme. It is an activity under the action SAFECONSTRUCTION, Research in Support of Standardization in Construction and Construction Products

Duration 1st October,2008- 30th September, 2011.

Contact

Paolo Negro
European Commission - Joint Research Centre
Institute for the Protection and Security of the Citizen
Tel. +39 0332 785452 - Fax +39 0332 789049
paolo.negro@jrc.it

Consortium

RTD Providers:

  • POLIMI, Labor srl (Italy)
  • NTUA (Greece)
  • ITU (Turkey)
  • LNEC (Portugal)
  • U Ljubljana (Slovenia)
  • IPSC/ELSA

SME Associations:

  • Assobeton (Italy)
  • ANDECE (Spain)
  • ANPD (Portugal)
  • SEVIPS (Greece)
  • TPCA (Turkey)

Recent Publications