Several studies have shown that the application rules of the capacity design principle suggested for chevron braced frames are often not effective in preventing yielding or buckling of the columns of the braced frame. Indeed, the design procedures available in literature or in seismic codes either neglect or significantly underestimate bending moments in columns. These bending moments are negligible when braces are in the elastic range of behaviour, but they may become significant because of concentration of the interstorey displacement demand when the braced frame overcomes its elastic range of behaviour and braces of a few stories experience large inelastic deformations. The high values of bending moments undermine the seismic performance of concentrically braced frames if yielding or buckling of the columns occurs prior to the full exploitation of the ductility capacity of braces. A simple procedure has been recently proposed by the authors to estimate the bending moments in columns of braced frames at the achievement of the ductility capacity of braces. In this paper, the abovementioned procedure is applied to predict bending moments in columns of concentrically braced frames in the chevron configuration designed according to different design procedures available in literature. To assess the effectiveness of the procedure, the predicted values of bending moments are compared to those obtained by nonlinear dynamic analyses with reference to peak ground accelerations leading the structure to either significant damage or near collapse limit state.

Prediction of the Bending Moments in Columns of Concentrically Braced Frames in the Chevron Configuration

Bosco M.;Floridia A.;Marino E.;Rossi P. P.
2022-01-01

Abstract

Several studies have shown that the application rules of the capacity design principle suggested for chevron braced frames are often not effective in preventing yielding or buckling of the columns of the braced frame. Indeed, the design procedures available in literature or in seismic codes either neglect or significantly underestimate bending moments in columns. These bending moments are negligible when braces are in the elastic range of behaviour, but they may become significant because of concentration of the interstorey displacement demand when the braced frame overcomes its elastic range of behaviour and braces of a few stories experience large inelastic deformations. The high values of bending moments undermine the seismic performance of concentrically braced frames if yielding or buckling of the columns occurs prior to the full exploitation of the ductility capacity of braces. A simple procedure has been recently proposed by the authors to estimate the bending moments in columns of braced frames at the achievement of the ductility capacity of braces. In this paper, the abovementioned procedure is applied to predict bending moments in columns of concentrically braced frames in the chevron configuration designed according to different design procedures available in literature. To assess the effectiveness of the procedure, the predicted values of bending moments are compared to those obtained by nonlinear dynamic analyses with reference to peak ground accelerations leading the structure to either significant damage or near collapse limit state.
978-3-031-03810-5
978-3-031-03811-2
Capacity design
Design procedures
Seismic codes
Steel braced frames
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11769/545217
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