During the recent earthquakes in the Emilia-Romagna region of Italy, the cladding-to-structure connections, which were installed in industrial precast buildings did not perform as had been expected. In several precast buildings collapse of cladding panels was observed. This indicated the need for new research and improvements in the design and execution of such connections. In this study the cyclic response of a cladding-to-structure connections, which is most commonly used in the current European design practice of precast buildings was studied experimentally and analytically. Such connections consist of cold-formed or hot-rolled channels and hammer-head straps. Up until now no information has been available, in the existing literature, about the cyclic response of such connections in the plane of the cladding panels. The results of the performed experimental studies were used to develop reliable numerical models of typical connections, and to define appropriate procedures for the safe design of in-use connections.
COBISS.SI-ID: 7456865
In the presented study, a second-line back-up system for the seismic protection of cladding panels in RC precast buildings is first presented. The system consists of special anchoring elements and a rope restrainer. The latter is activated only in the case when the existing connections between the primary structure and the panel fail, resulting in the occurrence of relatively large impact forces in the restrainer and in the anchoring elements. In order to adequately design the constitutive parts of the system, a simple yet sufficiently accurate procedure for the estimation of the impact forces is needed. A relatively easy-to-use formula was therefore proposed for this purpose. Next, an extensive parametric study, using response history analysis (RHA), was performed and the influence of several parameters affecting the impact forces in the restrainers was studied. The results obtained in the study were used to evaluate the proposed analytical formula. Considering the simplicity of the proposed formula, its accuracy was good. It can therefore be applied to the design of short restrainers which could be used in reinforced concrete (RC) precast buildings for the protection of cladding panels against the effects of earthquakes.
COBISS.SI-ID: 7581793
The cladding panel connections, which are typically used in RC precast buildings in Europe, have been analyzed experimentally and analytically. Vertical as well as horizontal panels were addressed. The typical cladding panel connections were mostly designed to be used in the non-seismic regions. Even though a little was known about their seismic response they were extensively used in the seismic regions. The basic mechanisms of their seismic response were identified for the first time. Contrary to the prevailing opinion that cladding panels are most vulnerable in their out-of-plane direction, it was proved that the most critical components – connections typically fail due to the seismic effects in the plane of the panels. This observation was in a good agreement with the damage observed after recent earthquakes. Based on the experimental and analytical studies of complex response of typical cladding panel connections, appropriate robust engineering numerical models were defined, which can be used in the design practice. The design procedures developed, and the expressions, which can be used to estimate their displacement and strength capacity, were derived.
COBISS.SI-ID: 7949153