Seismic Fragility Assessment of SMA-Actively Confined Bridge Piers for Retrofitting and Precast Construction

Seismic Fragility Assessment of SMA-Actively Confined Bridge Piers for Retrofitting and Precast Construction | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Seismic Fragility Assessment of SMA-Actively Confined Bridge Piers for Retrofitting and Precast Construction Kazi Ishat Mushfiq, Bassem Andrawes This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8808544/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Reinforced concrete bridge piers in high seismic zones often experience steel congestion, particularly in new constructions with strict transverse reinforcement requirements in plastic hinge regions. Shape memory alloys (SMAs) have proven effective in retrofitting seismically deficient piers through active confinement, offering unique thermal prestressing capabilities, whereas other strengthening methods in plastic hinge regions have proven problematic. Precast concrete offers a unique advantage of sequentially applying steel and SMA confinement, which reduces steel congestion in plastic hinge regions without increasing the seismic demand. This paper evaluates the seismic vulnerability of precast and retrofitted piers actively confined with shape memory alloy spiral in the plastic hinge regions, explicitly considering the stress-strain response of actively confined concrete. A reference design, as per existing code provisions, is used as a target performance benchmark for the precast and the retrofitted pier designs. Incremental dynamic analysis (IDA) is performed to obtain the fragility curves for the suggested designs, and the required SMA wrapping length is proposed for both the precast and the retrofitted piers. The results indicate that the precast pier with an SMA wrapping length of half the section diameter and a 50% reduction in the transverse steel in the plastic hinge region can preserve the overall performance. Moreover, a longer SMA wrapping length equal to the section diameter is required for the retrofitted piers to achieve a similar performance level. Shape memory alloy Steel congestion Precast pier Active confinement Plastic hinge Seismic fragility Full Text Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8808544","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":595550506,"identity":"207b9f53-02d9-4650-99b7-47f1a5098fc1","order_by":0,"name":"Kazi Ishat Mushfiq","email":"","orcid":"","institution":"University of Illinois Urbana-Champaign","correspondingAuthor":false,"prefix":"","firstName":"Kazi","middleName":"Ishat","lastName":"Mushfiq","suffix":""},{"id":595550507,"identity":"c8994108-c7d6-4062-8f57-722524c13242","order_by":1,"name":"Bassem Andrawes","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3klEQVRIiWNgGAWjYHACAzDJz8zceCCBgYEHxJEgSotkM2MDiVoMDgC1wITwauGf3bztw882G3vj40AtD3fYyMg3MB+8zYNHi8SdY8Uze9vSErcdBmpJPJPGY3CALdkanxaGGznGDLzbDieYgbW0HeYxYOAxk8anRR6ohfHvtv/2xs1QLfIN/N/wajEAamHm3XaAcQMzVAvDAR42vFoMb6QVM8v+S06cAXEY0C+H2Ywt5+DRIncjeTPjmzN29vz9hw8+BAWdfHvzwxtv8HkfEzCTpnwUjIJRMApGARYAAMV7TXKPe3fCAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0002-8954-3751","institution":"University of Illinois at Urbana-Champaign","correspondingAuthor":true,"prefix":"","firstName":"Bassem","middleName":"","lastName":"Andrawes","suffix":""}],"badges":[],"createdAt":"2026-02-06 15:07:32","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8808544/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8808544/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":109284707,"identity":"71f076d5-7428-4ed4-ad83-279a7049252d","added_by":"auto","created_at":"2026-05-14 21:40:27","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1705793,"visible":true,"origin":"","legend":"","description":"","filename":"ManuscriptFeb62026.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8808544/v1_covered_c0adce25-ee14-428c-b252-62b3edb5a956.pdf"}],"financialInterests":"","formattedTitle":"Seismic Fragility Assessment of SMA-Actively Confined Bridge Piers for Retrofitting and Precast Construction","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Shape memory alloy, Steel congestion, Precast pier, Active confinement, Plastic hinge, Seismic fragility","lastPublishedDoi":"10.21203/rs.3.rs-8808544/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8808544/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eReinforced concrete bridge piers in high seismic zones often experience steel congestion, particularly in new constructions with strict transverse reinforcement requirements in plastic hinge regions. Shape memory alloys (SMAs) have proven effective in retrofitting seismically deficient piers through active confinement, offering unique thermal prestressing capabilities, whereas other strengthening methods in plastic hinge regions have proven problematic. Precast concrete offers a unique advantage of sequentially applying steel and SMA confinement, which reduces steel congestion in plastic hinge regions without increasing the seismic demand. This paper evaluates the seismic vulnerability of precast and retrofitted piers actively confined with shape memory alloy spiral in the plastic hinge regions, explicitly considering the stress-strain response of actively confined concrete. A reference design, as per existing code provisions, is used as a target performance benchmark for the precast and the retrofitted pier designs. Incremental dynamic analysis (IDA) is performed to obtain the fragility curves for the suggested designs, and the required SMA wrapping length is proposed for both the precast and the retrofitted piers. The results indicate that the precast pier with an SMA wrapping length of half the section diameter and a 50% reduction in the transverse steel in the plastic hinge region can preserve the overall performance. 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