Indicators of improvements in seismic performance possible through retrofit of reinforced concrete frame buildings

Harrington, Cody C.; Liel, Abbie B.

doi:10.1177/8755293020936707

Cited by 8 publications

(10 citation statements)

References 28 publications

(49 reference statements)

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“…This trend can be empirically inferred from past results (e.g. Aljawhari et al, 2021; Harrington and Liel, 2021). Such a trend can also be demonstrated on theoretical grounds under specific conditions.…”

Section: Fragility-oriented Retrofit Designmentioning

confidence: 71%

“…Contrarily, other studies considered applying different retrofit techniques with varying intervention levels to achieve various performance objectives (e.g. Harrington and Liel, 2021; Ligabue et al, 2018), but only collapse fragility relationships were evaluated. These studies also attempted to map different performance metrics to decision variables of interest, such as collapse risk and/or seismic losses, to provide insight into their correlation.…”

Section: Introductionmentioning

confidence: 99%

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A fragility-oriented approach for seismic retrofit design

2022

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This study proposes a practical fragility-oriented approach for the seismic retrofit design of case-study structures. This approach relies on mapping the increase of the global displacement-based ratio of capacity to life-safety demand ( CDRLS) to the building-level fragility reduction. Specifically, the increase of CDRLS due to retrofitting is correlated with the corresponding shift in the fragility median values of multiple structure-specific damage states, observing that a pseudo-linear trend is appropriate under certain conditions. Accordingly, a practical approach is proposed to fit such a (structure-specific) linear trend and then use it by first specifying the desired fragility median and subsequently finding the corresponding target value of CDRLS that must be achieved through retrofit design. The validity of the proposed approach is illustrated for an archetype reinforced concrete (RC) structure not conforming to modern seismic design requirements, which has been retrofitted using various techniques, namely, fiber-reinforced polymers wrapping of columns and joints, RC jacketing, and steel jacketing.

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Section: Fragility-oriented Retrofit Designmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 99%

A fragility-oriented approach for seismic retrofit design

2022

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“…It should be noted that the unique failure modes pertaining to FRP, such as debonding and fracture mechanisms, are not explicitly modeled, assuming the FRP retrofitting is designed and installed appropriately so that the concrete and reinforcement will govern the softening behavior of the retrofitted elements at high levels of deformation (e.g. [22], [45]).…”

Section: Nonlinear Modeling Strategiesmentioning

confidence: 99%

“…In the case of FRP or steel jacketing, the concept of equivalent transverse reinforcement is implemented (e.g. [12], [22], [45]). In this approach, the FRP or steel jacketing can be simply converted to standard transverse reinforcement that mimics their effect by generating a lateral confining pressure equal to that produced by either of them.…”

Section: Damage State Definition and Thresholds Mappingmentioning

confidence: 99%

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Mapping Performance-Targeted Retrofitting to Seismic Fragility Reduction

Aljawhari¹,

Gentile²,

Galasso³

2021

Proceedings of the 8th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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This study investigates the improvement in the seismic performance of an archetype reinforced concrete (RC) frame due to varying structural retrofit levels. Specifically, the study attempts to map the increase of the displacement-based global ratio between capacity and life-safety demand (CDRLS) to the reduction of seismic fragility. Such a reduction is characterized by the shift of the median fragility for different structure-specific damage states (DSs). The considered structure does not conform to modern seismic design requirements, and it is retrofitted using various techniques. Advanced nonlinear models are developed for the archetype frame, accounting for potential failure mechanisms, including flexural, joint, and shear failure. Three common retrofitting techniques are investigated, namely RC jacketing, steel jacketing, and fiber-reinforced polymers (FRP) wrapping of columns and joints. Each technique is specifically designed and proportioned to achieve predefined performance objectives (i.e., performancetargeted retrofitting), thus generating many retrofit alternatives. The improvement in seismic performance for the retrofitted frames is first characterized by computing the global CDRLS, which can be obtained using nonlinear pushover analysis combined with the Capacity Spectrum Method. Subsequently, cloud-based nonlinear time-history analyses are performed to derive fragility relationships for the as-built and retrofitted configurations, monitoring the variation in the median fragility for all DSs. Finally, the global CDRLS increase due to retrofitting is correlated with the corresponding shift in the median fragility. A linear trend is found, and it is used accordingly to develop simple models that engineers can implement to provide reasonable estimates for such shift once the global CDRLS is known.

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Functional recovery evaluation of hybrid self‐centering piston‐based braced frames

Rahgozar,

Alam

2023

Earthq Engng Struct Dyn

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Severe earthquakes possess formidable destructive potential, leading to substantial damage, widespread disruptions, and tragic loss of life. In response, researchers and policymakers strive to develop innovative solutions to quantify the seismic resilience of structures. This study aims to evaluate the post‐earthquake functional recovery of two types of braced frames: Self‐Centering Piston‐Based Braced Frames (SC‐PBBFs) and Buckling Restrained Braced Frames (BRBFs). The SC‐PBBFs are designed to mitigate structural damage by incorporating Self‐Centering Piston‐Based Bracings (SC‐PBBs) equipped with Shape Memory Alloy (SMA) bars and Friction Springs (FS). A set of building prototypes, representing low‐, mid‐, and high‐rise archetypes in seismic regions, are subjected to comprehensive analyses under 44 far‐field ground motions. This thorough examination incorporates seismic hazards, structural demands, and component damages to quantify the earthquake‐induced losses and repair timelines. The study findings indicate that BRBFs suffer more significant collapse losses than SC‐PBBFs. However, BRBF systems incur lower repair costs, mainly due to limited damage to acceleration‐sensitive non‐structural components. Additionally, the FEMA P‐58/ATC‐138 framework is employed to estimate re‐occupancy, functional recovery, and full repair time, identifying systems and components that exert a significant impact on functional recovery.

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Indicators of improvements in seismic performance possible through retrofit of reinforced concrete frame buildings

Cited by 8 publications

References 28 publications

A fragility-oriented approach for seismic retrofit design

A fragility-oriented approach for seismic retrofit design

Mapping Performance-Targeted Retrofitting to Seismic Fragility Reduction

Functional recovery evaluation of hybrid self‐centering piston‐based braced frames

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