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

Barbagallo, Francesco; Bosco, Melina; Marino, Edoardo M.; Rossi, Pier Paolo

doi:10.1002/eqe.3105

Cited by 16 publications

(6 citation statements)

References 43 publications

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“…In the recent past, several studies have suggested a combined approach to building renovation. Among all the possible combined intervention strategies, those that can be performed from the outside are more appealing [9][10][11][12], because they reduce the disruption to the occupants during the works and do not require their relocation. La Greca and Margani [4] have highlighted the advantages of combined renovation actions, indicating the barriers that currently limit such actions and suggesting possible countermeasures.…”

Section: The State Of Art Of Combined Retrofit Interventionsmentioning

confidence: 99%

Decision Support System for the Sustainable Seismic and Energy Renovation of Buildings: Methodological Layout

et al. 2020

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In Italy, as in many other European countries, a large part of the real estate was built before the issue of restrictive regulations regarding seismic resistance and energy efficiency. Consequently, most existing buildings show inadequate structural and energy performance. However, although a combined renovation is highly recommended, and despite relevant tax incentives which are currently available, the building retrofit market is still struggling to take off. In fact, the lack of information and/or awareness of the involved parties and the consequent difficulty for condominiums to approve the retrofit works are often insuperable obstacles. A Decision Support System (DSS) may help in evaluating and comparing different combined renovation scenarios, thus promoting the regeneration of the building stock. This study presents a new methodology for the selection of the optimal building renovation scenario through a DSS, which is conceived as a tool to allow a quick, simple and effective identification of the best retrofit strategy, based on a priority scale (e.g., costs and duration of intervention, disruption to the occupants, environmental sustainability, energy savings, thermal comfort, structural safety). For this purpose, the DSS calculates suitable performance indices and relative costs. Finally, the system proposes a ranking of the best combined retrofit scenarios. This research study is still ongoing and next steps will deal with the calibration of the proposed methodology.

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Section: The State Of Art Of Combined Retrofit Interventionsmentioning

confidence: 99%

Decision Support System for the Sustainable Seismic and Energy Renovation of Buildings: Methodological Layout

et al. 2020

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“…In regard to the inelastic behaviour of braces in tension, some research studies have highlighted the importance of the flexural stiffness of the braced beams. 2,7,8 Indeed, flexible braced beams limit the inelastic elongation of braces under tension and sometimes prevent these members from yielding. Conversely, stiff beams ensure large plastic elongations and thus high energy dissipation prior to brace fracture.…”

Section: Introductionmentioning

confidence: 99%

Proposal and validation of a design procedure for concentrically braced frames in the chevron configuration

Barbagallo

Bosco

Marino

et al. 2021

Earthq Engng Struct Dyn

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In the recent past, several research studies have highlighted that the prescriptions reported in codes for the design of structures with concentric braces in the chevron configuration are often not effective in preventing yielding or buckling of non‐dissipative members and in ensuring collapse mechanisms characterised by uniform damage of braces. To investigate the reasons of these deficiencies, in this paper the seismic response of concentrically braced structures designed according to procedures reported in the literature and in the European seismic code is first examined. Then, a new design procedure is proposed, in which the innovative aspects are mainly related to the estimation of the bending moments in columns and to the formulation of requirements on the stiffness of braced beams and columns. The impact of the proposed procedure on the structural costs is computed on a large number of buildings characterised by different occupancy types and geometric properties. The seismic performance of these structures is evaluated by incremental nonlinear dynamic analysis and discussed at the achievement of the significant damage and near‐collapse limit states.

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“…However, the relative displacement caused by the added damping depends to a great extent on the properties of the adjacent structures, 11 so local strengthening of the existing slabs connected to the dampers may also be required 10 . Another alternative is the use of external post‐tensioned walls 12–17 and steel braced towers, 18,19 centrally pinned at the foundation to impose uniform interstorey drift along the height of the frame. It should be noted that the self‐weight of pinned rocking systems acts against stability, leading to permanent displacement unlike stepping rocking wall able to re‐centre because of gravity 20 .…”

Section: Introductionmentioning

confidence: 99%

Dissipative steel exoskeletons for the seismic control of reinforced concrete framed buildings

Mazza

2020

Struct Control Health Monit

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Summary The insertion of steel bracing systems equipped with dissipative devices is a widely used technique for the seismic retrofitting of reinforced concrete (r.c.) framed buildings; yet, few attempts have been made so far to construct an external arrangement in the form of a double skin. The dissipative exoskeleton (DEX) appears convenient from energetic and functional points of view. It eliminates the indirect costs associated with downtime during retrofitting and cuts out the unwanted effects to the existing structure that commonly arise with the dissipative endoskeleton. This paper provides a DEX sizing procedure through use of overdamped elastic response spectra, which could prove a valuable tool for practitioners. The DEX is designed on the assumption of a rigid coupling with the existing structure, making a distinction between mass and stiffness properties of the steel exoskeleton and added damping of the dissipative bracing system. Concentrically braced chevron frames with pinned joints and damped bracing systems incorporating fluid viscous dampers (FVDs) are considered. Elastic‐linear behaviour of steel frame members and nonlinear pure viscous dashpot for FVDs, with a storey‐shear proportional distribution, are hypothesised. The retrofitting of a six‐storey r.c. framed structure, representative of the Italian residential buildings designed for moderate seismic loads during the 1990s, is to be simulated in a high risk‐seismic region. Three external arrangements of DEX are selected: parallel (DEX.Pa) and perpendicular (DEX.Pe) to all façades of the existing building and a mixed solution (DEX.Mi) with both parallel and perpendicular disposition placed along the shorter façades without apertures. Nonlinear structural models of the original (F) and coupled (DEXF) structures are developed in OpenSEES, considering ductile and brittle failure modes of r.c. elements and joints. The seismic analyses not only confirm the effectiveness of the proposed DEX design but also provide insights into the strength and weaknesses of the examined configurations.

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

Cited by 16 publications

References 43 publications

Decision Support System for the Sustainable Seismic and Energy Renovation of Buildings: Methodological Layout

Decision Support System for the Sustainable Seismic and Energy Renovation of Buildings: Methodological Layout

Proposal and validation of a design procedure for concentrically braced frames in the chevron configuration

Dissipative steel exoskeletons for the seismic control of reinforced concrete framed buildings

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