Damage Concentration Effect of Multistory Buckling‐Restrained Braced Frames

Abstract

Due to the low postyield stiffness of buckling-restrained braces (BRBs), multistory buckling-restrained braced frames (BRBFs) subjected to earthquakes are prone to lateral deformations and damage concentrations at certain stories, which is deemed a damage concentration effect (DCE). A series of nonlinear pushover analyses and response history analyses are conducted to investigate the key factors affecting the DCE of BRBFs. Two comparisons of the DCE are performed for different types of structures and different beam-to-column connections in the main frame (MF). These comparisons show that BRBFs equipped with BRBs as the main earthquake resistance system have a more serious DCE than the traditional moment-resisting frame or conventional braced frame and that the MF stiffness significantly affects the structural residual displacement and DCE. Then, parametric analyses are performed to investigate the influence of two stiffness distribution parameters (in the horizontal and vertical directions) on the DCE of a 6-story BRBF dual system designed according to the Chinese seismic code. The results show that increasing the MF stiffness and avoiding abrupt changes in the BRB stiffness between stories can effectively mitigate the DCE of BRBFs. Finally, the correlations between various damage performance indices are analyzed. A low statistical correlation between the peak and residual drift responses can be observed in BRBFs. Therefore, it is recommended that the DCE be considered in BRBF design.

Eurocode‐8‐conforming seismic design and behaviour factor of high‐post‐yield stiffness concentrically‐braced steel frames

“…16,17 Still, they are prone to damage concentration at specific storeys because of their relatively low post-yield stiffness. 18,19 To reduce the residual drifts, several novel systems have been proposed. Examples include dual BRBFs-MRFs [20][21][22] and dual systems incorporating both BRBFs and self-centering concentrically braced frames.…”

Comparison of Novel Seismic Protection Devices to Attenuate the Earthquake Induced Energy

“…Similarly, viscous dampers (VDs) have been utilized as a passive energy dissipating device for seismic protection of the structures. Both BRBs and VDs are capable of controlling the deformations developed in steel frames by dissipating the energy or increasing the stiffness [16][17][18][19][20].…”

Steel Frames Exposed to Severe Ground Motions: Use of Viscous Dampers and Buckling Restrained Braces to Dissipate Earthquake Induced Energy

“…Both BRBs and VDs are capable of controlling the deformations developed in steel frames by dissipating the energy or increasing the stiffness. Hence, they have been involved in improving the seismic performance of the overall structures [11][12][13][14].…”