The role of claddings in the seismic response of precast structures: the SAFECLADDING full-scale tests

The knowledge gained with different research projects, focused on seismic performance of precast reinforced-concrete buildings and during different earthquakes, permits to observe that the frame resisting systems, if designed for seismic actions, maintain their efficiency. On the contrary, the façade cladding and the connections between structure and panels, can meet with failure. These observations draw the attention to the need of further research on this field. The SAFECLADDING Project was started to tackle this issue with the aim to Improve Fastening Systems of Cladding Panels for Precast Buildings in Seismic Zones. It is a Research Project for SMEs associations, granted by EU FP7 which involves seven industrial partners: enterprises, European or national associations of precast concrete producers; four universities and the European Laboratory for Structural Assessment (ELSA). The SAFECLADDING Project analyses the ways to improve the performance of existing buildings, as well as the new ones. Three different Approaches can be followed to enhance the connections in frame-cladding system: Isostatic, Integrated, and Dissipative. The experiment, the mock-up and the test sequence were designed to assess the most common cladding systems using the same frame structure. The mock-up is a single-storey building made by six square columns, inserted into pocket foundations. The columns bear four roof beams and seven slabs, with masses comparable to the common construction with this typology. Two main Façade Arrangements, with horizontal and vertical panels, were selected as the most common in the European industrial buildings. Also different connection layouts subdivide each façade arrangements into different Setups for vertical and horizontal panels. The displacement are applied to the building roof using two pairs of hydraulic actuators for a total load capacity up to 2000 kN, each one equipped by a cell to measure the load. The drift at roof level is continuously measured by two digital displacement transducers. All the other measures of displacements, rotations and deformations are acquired by a network of analog transducers, integrated by optical measurements to capture the displacements of the panels and rigid displacements of the devices included to dissipate energy. The joints involved in the experiments can be classified by the role-played as: Panel-to-Frame, Panel-to-Panel and Simple Retain. The experimental programme, foresees nine different setups for vertical-panel arrangement with twenty-five tests and seven different setups for horizontal-panel arrangement with other nineteen tests. Hence every setup is tested using increasing levels of action, which are quasi static Push-Over (PO) up to 0.9% of drift ratio, and Pseudo Dynamic (PsD) both at Serviceability Limit State (SLS) and at Ultimate Limit State (ULS).

NEGRO Paolo;  LAMPERTI TORNAGHI Marco; 

2014-09-04

European Association for Earthquake Engineering

JRC90755