Experimental Investigation of Flanged Tube Retrofitting Effects on Reinforced Concrete Beams with Web Openings

Experimental Investigation of Flanged Tube Retrofitting Effects on Reinforced Concrete Beams with Web Openings | 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 Experimental Investigation of Flanged Tube Retrofitting Effects on Reinforced Concrete Beams with Web Openings Mohammad Zuhair, Parikshit N. Deshmukh This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7468328/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 (RC) beams are commonly used in modern construction because of their strength and flexibility. However, making web openings for services like electrical conduits, HVAC ducts, and plumbing lines often results in decreased stiffness, strength, and premature cracking. Several studies [ 1 – 6 ] have shown that these openings negatively impact the shear capacity, crack progression, and overall load-bearing ability of beams. To address these issues, various strengthening and retrofitting methods, such as FRP wrapping, steel plate bonding, and hybrid techniques, and have been examined [ 7 – 12 ]. While these methods provide some improvements, there are still challenges regarding cost, build ability, and long-term durability. This experimental study introduces a new retrofitting technique that uses flanged tube inserts to improve the performance of RC beams with circular web openings. A series of beam specimens, both with and without the retrofitted flanged tubes, were tested under four-point bending to assess load-carrying capacity, stiffness, deflection behavior, and crack patterns. The results showed that flanged tube retrofitting greatly improved shear resistance, lowered stress concentration around openings, and enhanced energy absorption compared to unstrengthened specimens. This technique offers a promising, practical, and cost-effective solution for retrofitting RC beams with service openings, ensuring better usability and structural safety. Reinforced concrete beams web openings flanged tube retrofitting experimental investigation load-deflection behavior and crack pattern Full Text Additional Declarations No competing interests reported. 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-7468328","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":538502863,"identity":"e20e6c5a-b423-4187-960c-d3eac153bdeb","order_by":0,"name":"Mohammad Zuhair","email":"","orcid":"","institution":"P.R. Pote Patil College of Engineering \u0026 Management","correspondingAuthor":false,"prefix":"","firstName":"Mohammad","middleName":"","lastName":"Zuhair","suffix":""},{"id":538502864,"identity":"c0b3bfc0-5063-4301-8012-3740860a70b3","order_by":1,"name":"Parikshit N. 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Openings","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":"Reinforced concrete beams, web openings, flanged tube retrofitting, experimental investigation, load-deflection behavior, and crack pattern","lastPublishedDoi":"10.21203/rs.3.rs-7468328/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7468328/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eReinforced concrete (RC) beams are commonly used in modern construction because of their strength and flexibility. However, making web openings for services like electrical conduits, HVAC ducts, and plumbing lines often results in decreased stiffness, strength, and premature cracking. Several studies [\u003cspan additionalcitationids=\"CR2 CR3 CR4 CR5\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] have shown that these openings negatively impact the shear capacity, crack progression, and overall load-bearing ability of beams. To address these issues, various strengthening and retrofitting methods, such as FRP wrapping, steel plate bonding, and hybrid techniques, and have been examined [\u003cspan additionalcitationids=\"CR8 CR9 CR10 CR11\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. While these methods provide some improvements, there are still challenges regarding cost, build ability, and long-term durability. This experimental study introduces a new retrofitting technique that uses flanged tube inserts to improve the performance of RC beams with circular web openings. A series of beam specimens, both with and without the retrofitted flanged tubes, were tested under four-point bending to assess load-carrying capacity, stiffness, deflection behavior, and crack patterns. The results showed that flanged tube retrofitting greatly improved shear resistance, lowered stress concentration around openings, and enhanced energy absorption compared to unstrengthened specimens. This technique offers a promising, practical, and cost-effective solution for retrofitting RC beams with service openings, ensuring better usability and structural safety.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e","manuscriptTitle":"Experimental Investigation of Flanged Tube Retrofitting Effects on Reinforced Concrete Beams with Web Openings","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-03 09:31:09","doi":"10.21203/rs.3.rs-7468328/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","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}}],"origin":"","ownerIdentity":"a76fde7c-477e-41a8-b74e-2bd47f0aa02d","owner":[],"postedDate":"November 3rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-03-11T09:24:33+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-03 09:31:09","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7468328","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7468328","identity":"rs-7468328","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}