Seismic behavior of cross-laminated timber panel buildings equipped with traditional and innovative connectors

The aim of this paper is to analyze the possibility to improve the seismic performance of cross-laminated timber (CLT) panel buildings introducing in the structure dissipative connectors in substitution of the classical hold-downs. In fact, as demonstrated by past experimental tests and numerical analyses, hold-downs exhibit a limited dissipation capacity. The proposed dissipative connector is called XL-stub and applies the concept usually adopted for ADAS devices. In order to prove the effectiveness of the proposed system the results of an experimental program devoted to characterize the force–displacement response under cyclic loads and low fatigue behavior of the XL-stub are presented and compared to the results of cyclic tests of hold-downs with same resistance. Afterwards, the comparison is extended at the level of the building, evaluating the influence of the connection on the seismic performance of the whole CLT panel building. To this scope, a FE model of the three-storey building tested within the SOFIE project is calibrated and multiple transient dynamic analyses are performed both for the building with the classical layout of connections and for the building equipped with XL-stubs. The obtained results are compared and the values of the behavior factor for the two solutions are calculated.