PSI - Issue 44

Francesco Morelli et al. / Procedia Structural Integrity 44 (2023) 574–581 Francesco Morelli, Agnese Natali, Gabriele Poggi / Structural Integrity Procedia 00 (2022) 000–000

576

3

One of the key parameters that influence the overall dynamic behavior of the HCSWs is the coupling ratio (CR), defined as expressed in eq. (1). ≥ ∙ 2 + 2 + ( ∙ ) (1) Numerous researches (Dall’Asta et al. 2015; Zona et al. 2016; Das et al. 2018) investigated the optimal values of the CR, studying both the possibility of using the same profile for all the dissipative links along the height (“uniform distribution”) and of varying it to optimize the dissipation capacity (“non-uniform distribution”). All these studies used nonlinear analyses, both static and dynamic, to assess the seismic performance of the HCSWs. They highlighted, at the same time, the influence of the higher modes on the global structural response for higher buildings along with the difficulties in catching the correct behavior through simplified, static, nonlinear analysis. To this end, the present paper shows the results of incremental dynamic analyses used to gain a deeper insight on the dynamic behavior of high-rise HCSWs, and of multimodal nonlinear static analyses used to better represent the To analyze the dynamic behavior of HCSWs, the 6-storeys structure studied by (Das et al. 2018) and represented in Fig. 3 was used. The building is regular in plan and has two HCSWs in each direction, Fig. 3a, and the interstorey height is 3.50 m. As regard the gravitational loads, the permanent and variable floor ones are 4.30 and 2.00 kN/m2, while the permanent and variable roof ones are 3.30 and 1.97 kN/m2, respectively. The concrete class for the RC wall is C30 (characteristic cylindrical compressive strength fck = 30 MPa) and the reinforcements are B450C (characteristic yield stress fyk = 450 MPa). Complete details of the geometry and mechanical properties of the case study can be found in (Das et al. 2018). a b global response than classical nonlinear static analyses. 2. Case study: properties and numerical models

Fig. 3. (a) Plan view; (b) front view of the case study structure.

Among all the case studies analyzed by (Das et al. 2018), in the present research it was considered the 6-storey structure with a CR of 0.6 and uniform link distribution. The global model of the HCW system is developed in OpenSEES (Mazzoni et al. 2007): the RC wall is modelled using a force-based distributed-plasticity element with fiber section, Fig. 4, whereas the Steel Links using a lumped plasticity model. All the finite elements are placed in correspondence of the axes of the corresponding structural element and connected among them by means of rigid elements to consider the actual eccentricity (Fig. 5). The masses related to permanent and live loads are applied to the equivalent leaning columns while the mass associated to the self-weight of structural elements is lumped at the end nodes of each element. The leaning column with gravity loads is linked to the frame by truss elements, to simulate P-Delta effects. The leaning columns are modeled as elastic beam-column elements. The column is connected to the beam by zeroLength rotational spring element,