EXPERIMENTAL CHARACTERIZATION OF A TWO-STOREY STEEL FRAME EQUIPPED WITH CRESCENT-SHAPED BRACES

The work provides the main results of an experimental campaign aimed at assessing the structural response of steel frame structures braced with so-called Crescent Shaped Braces (CSB) hysteretic devices. The CSB is a steel dissipative device having a kind of “boomerang” shape that connect two points of a structure (either two elements of the same floor, in a link-type configuration, or two different stories, in a brace-type configuration) The particular geometrical shape of the device is responsible of a specific non-linear behavior characterized by an elasto-plastic range followed by a final hardening, when subjected to traction, or by an elasto-plastic range followed by a slight softening, when subjected to compression. The insertion of ad-hoc designed CSB devices in not-moment resisting frames as diagonal braces allows to obtain an enhanced lateral resting system characterized by an optimized global force-displacement behavior capable of satisfying multiple seismic performance objectives. In previous investigations the behaviour of CSB have been investigated by means of analytical studies, numerical simulations and experimental tests on scaled (1:6) specimens. The objective of the paper is to provide the main experimental results and first interpretation of a series of tests conducted at the laboratory CIRI Buildings & Construction of the University of Bologna on a 1:2 scaled two-storey steel frame prototype structure incorporating diagonal CSB devices.