Application of Crescent-Shaped Brace passive resisting system in RC frame structures

The design of building structures that is capable of providing prescribed seismic performances is the fundamental objective of the Performance-Based Seismic Design (PBSD) approach. Matching a particular seismic response requires additional design freedom that the conventional structural elements (beam/column) fail to provide. Here, it is worth to highlight the role of innovative lateral resisting systems such as base isolation and dissipative systems, which can add flexibility to the design and help to achieve prefixed seismic performance objectives. Among different solutions, the seismic design of a two-storey reinforced concrete building equipped with a novel hysteretic device, namely Crescent-Shaped Brace (CSB), is presented. CSBs are characterised by a unique geometrical configuration, leading to an optimized nonlinear force-displacement behaviour that allows the structure to achieve prescribed multiple seismic performances. In this paper, we propose a procedure for the seismic design of the CSB devices within the framework of PBSD. The global behaviour of the devices is studied and verified for a multi-storey shear-type building structure by means of numerical analyses. The results obtained confirm the validity of the proposed design method and the effectiveness of the new hysteretic device. The force-displacement curve of the building matches the objectives curve (i.e. the one corresponding to the predefined performance objectives), thus ensuring the fulfilment of the prescribed multi-seismic performances.