A Capacity Design Procedure for Columns of Steel Structures with Diagonals Braces

Bosco, Melina; Ghersi, Aurelio; Marino, Edoardo M.; Rossi, Pier Paolo

doi:10.2174/1874836801408010196

Cited by 26 publications

(14 citation statements)

References 40 publications

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“…Consequently, the interstorey displacements are not constant along the height of the building, and the columns are significantly deformed in flexure. Thus, significant values of the bending moments arise in columns that are designed to sustain only axial forces . In systems “04C1‐235‐R”, “08C1‐235‐R”, and “12C1‐235‐R” (not included in the tables), the values of the PGA leading to a maximum interstorey displacement equal to 1.25% h are 0.245, 0.105, and 0.124 g, respectively.…”

Section: Application To Case Studiesmentioning

confidence: 99%

Seismic retrofitting of braced frame buildings by RC rocking walls and viscous dampers

Barbagallo

Bosco

Marino

et al. 2018

Earthq Engng Struct Dyn

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Summary A design procedure for seismic retrofitting of concentrically and eccentrically braced frame buildings is proposed and validated in this paper. Rocking walls are added to the existing system to ensure an almost uniform distribution of the interstorey displacement in elevation. To achieve direct and efficient control over the seismic performance, the design procedure is founded on the displacement‐based approach and makes use of overdamped elastic response spectra. The top displacement capacity of the building is evaluated based on a rigid lateral deformed configuration of the structure and on the ductility capacity of the dissipative members of the braced frames. The equivalent viscous damping ratio of the braced structure with rocking walls is calculated based on semi‐empirical relationships specifically calibrated in this paper for concentrically and eccentrically braced frames. If the equivalent viscous damping ratio of the structure is lower than the required equivalent viscous damping ratio, viscous dampers are added and arranged between the rocking walls and adjacent reaction columns. The design internal forces of the rocking walls are evaluated considering the contributions of more than one mode of vibration. The proposed design procedure is applied to a large set of archetype braced frame buildings and its effectiveness verified by nonlinear dynamic analysis.

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Section: Application To Case Studiesmentioning

confidence: 99%

Seismic retrofitting of braced frame buildings by RC rocking walls and viscous dampers

Barbagallo

Bosco

Marino

et al. 2018

Earthq Engng Struct Dyn

View full text Add to dashboard Cite

show abstract

“…The safety level of all the other members (top storey braces, columns, zipper columns and beams) against flexural buckling is evaluated by means of the ratio B

B = max \frac{N_{Ed} ((),, t)}{N_{normalb, Rd, ((),, M)} ((),, t)}

where N Ed is the design axial force of the member and N b,Rd (M) is the design buckling resistance due to combined axial force and bending moment. The expressions of N b,Rd (M) are derived from the interaction formulae specified in EC3 .…”

Section: Numerical Analysesmentioning

confidence: 99%

“…where N Ed is the design axial force of the member and N b,Rd (M) is the design buckling resistance due to combined axial force and bending moment. The expressions of N b,Rd (M) [41,42] are derived from the interaction formulae specified in EC3 [31]. The relationships used for the calculation of the safety level of the non-dissipative members against yielding are different depending on the member considered.…”

Section: Numerical Analysesmentioning

confidence: 99%

A design procedure for suspended zipper‐braced frames in the framework of Eurocode 8

Rossi

Quaceci

2017

Earthq Engng Struct Dyn

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Summary In the recent past, suspended zipper‐braced frames were proposed to avoid one‐storey collapse mechanisms and dynamic instability under severe ground motions. In this paper, the design procedure suggested by Yang et al. is first slightly modified to conform to the design approach and capacity design rules stipulated in Eurocode 8 for concentrically braced frames. The procedure is applied to a set of suspended zipper‐braced frames with different number of storeys and founded on either soft or rock soil. The structural response of these frames is analysed to highlight qualities and deficiencies and to assess the critics reported by other researchers with regard to the design procedure by Yang et al. Then, improvements are proposed to this procedure to enhance the energy dissipation of the chevron braces and the response of the structural system as well. The effectiveness of the design proposals is evaluated by incremental dynamic analysis on structures with different geometric properties, gravity loads and soil of foundation. Copyright © 2017 John Wiley & Sons, Ltd.

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“…To mitigate this disadvantage, Yu et al [9] proposed a less demanding design procedure for elastic braces, zipper columns and columns. In complying with the usual design approach of CBFs, these procedures considered only the axial force for the design of the members and, therefore, left the braced columns prone to failure because of unexpected and non-negligible bending moments, as noted in recent research studies on CBFs [10]. The above procedures also provided no provision for the control of the effectiveness of the suspension system, which is variable in elevation because of the axial deformability of members.…”

Section: Introductionmentioning

confidence: 99%

11.46: The design of suspended zipper braced frames in the framework of eurocode 8

et al. 2017

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To counteract the tendency of chevron-braced structures to form soft storey mechanisms during earthquakes, some researchers have proposed the addition of zipper columns between brace locations at midspan of floor beams and the design of an elastic hat truss system. In this paper, the design procedure proposed by Yang et al. for suspended zipper braced frames is first slightly modified to conform to the design approach and capacity design rules stipulated in Eurocode 8 (EC8) for concentrically braced frames. The procedure is applied to a set of structures with different number of storeys and founded on either soft or rock soil and the structural response is analysed to highlight qualities and deficiencies of the above design procedure. Some improvements are then proposed to the design procedure proposed by Yang et al. to achieve a better seismic performance of the suspended zipper braced frames. Compared with this latter design procedure, the proposed procedure allows a more accurate evaluation of the internal forces -axial forces and bending moments -and a direct control of the inelastic response of chevron-braces of all storeys. The effectiveness of the design proposal is evaluated by incremental dynamic analysis on structures characterised by a different number of storeys and soil of foundation.

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A Capacity Design Procedure for Columns of Steel Structures with Diagonals Braces

Cited by 26 publications

References 40 publications

Seismic retrofitting of braced frame buildings by RC rocking walls and viscous dampers

Seismic retrofitting of braced frame buildings by RC rocking walls and viscous dampers

A design procedure for suspended zipper‐braced frames in the framework of Eurocode 8

11.46: The design of suspended zipper braced frames in the framework of eurocode 8

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