Seismic demand on brace-intersected beams in two-story X-braced frames

High strength steel in chevron concentrically braced frames designed according to Eurocode 8

“…Indeed, the vertical deflection of those beams imposes larger ductility demand for braces in compression, thus deteriorating the story strength and stiffness and concentrating the damage at those stories. These results are also in line with recent studies carried out by Shen et al [44,45]. These Authors showed that brace-intercepted beams designed with the minimum required strength permitted by the current US design provisions could undergo significant vertical inelastic deformations which considerably increase ductility demands on both braces and beam-to-column connections.…”

“…The second feature is induced by the low flexural strength and stiffness of the brace-intercepted beams, which correspond to large compression demand in the braces, as early shown by [35,[44][45][46][47][48][49][50]. In the most of examined cases, the beam deflection caused by the unbalanced force is large enough to prevent tensile yielding of the brace in tension and to increase the damage in the compression diagonal at SD limit state.…”

The influence of beam stiffness on seismic response of chevron concentric bracings

“…More recently, the numerical studies carried out by Shen et al [21,22] concluded that brace-intercepted beams designed with the minimum possible required strength permitted by the current US design provisions could undergo significant vertical inelastic deformations for interstorey drift ratios ranging within 0.02-0.04. Similar to the results obtained in [19], Shen et al [21,22] also observed that the inelastic deformations in the middle spans of brace-intercepted beams considerably increase ductility demands on both braces and beam-to-column connections.…”

Assessment of the Design Criteria for Concentric V-Braced Steel Structures According to Italian and European Codes

“…Another key aspect responsible for the poor overall response of chevron CBFs has been recently evidenced in literature, being related to the beam flexural stiffness [26,27].…”