Systematic Experimental Evaluation of EB and NSM FRP Strengthening Configurations for RC Beams: Strength, Ductility, and Failure Mechanisms

Systematic Experimental Evaluation of EB and NSM FRP Strengthening Configurations for RC Beams: Strength, Ductility, and Failure Mechanisms | 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 Systematic Experimental Evaluation of EB and NSM FRP Strengthening Configurations for RC Beams: Strength, Ductility, and Failure Mechanisms E. A. HASSAN, M. S. Zahran, A. OSMAN, Nabil. M. Nagy This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9620259/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 7 You are reading this latest preprint version Abstract Although The flexural strengthening of reinforced concrete (RC) beams using fiber-reinforced polymer (FRP) systems has been widely investigated; however, consistent and systematic comparisons between externally bonded (EB) and near-surface mounted (NSM) techniques under identical conditions remain limited. This study presents a controlled experimental investigation aimed at directly comparing multiple EB and NSM FRP strengthening configurations within a unified framework. Six full-scale RC beams (170 × 260 × 1600 mm) were tested under three-point loading. One beam served as a control specimen, while five beams were strengthened using different configurations, including EB CFRP laminates (soffit and side-bonded), a CFRP sheet, and NSM GFRP bars (single and double). All specimens were designed with identical geometry, internal reinforcement, material properties, and loading conditions to ensure a consistent basis for comparison. The study extends beyond conventional strength assessment by providing an integrated evaluation of structural performance, including load-carrying capacity, stiffness development, ductility, crack propagation, and energy absorption. The results showed that all strengthening techniques significantly enhanced flexural performance, with increases in ultimate load ranging from approximately 50% to 85% compared to the control beam. EB CFRP configurations exhibited superior strength enhancement, while NSM GFRP systems demonstrated more reliable bond performance and improved crack control. However, strengthened beams generally showed reduced ductility compared to the control specimen due to the nonlinear-elastic behaviour of FRP materials. The findings highlight the critical influence of strengthening configuration on overall structural behaviour and provide a comprehensive basis for selecting appropriate FRP strengthening techniques based on performance requirements. This work contributes to a more reliable understanding of configuration-dependent behaviour through a consistent experimental approach and a multi-parameter performance assessment. Flexural Strengthening RC Beams CFRP GFRP ductility Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 09 May, 2026 Reviewers agreed at journal 09 May, 2026 Reviewers agreed at journal 08 May, 2026 Reviewers invited by journal 07 May, 2026 Editor assigned by journal 07 May, 2026 Submission checks completed at journal 07 May, 2026 First submitted to journal 05 May, 2026 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-9620259","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":637545827,"identity":"112cba9b-cdcf-4f1b-9b70-c8fae87fe632","order_by":0,"name":"E. A. HASSAN","email":"","orcid":"","institution":"Military Technical College","correspondingAuthor":false,"prefix":"","firstName":"E.","middleName":"A.","lastName":"HASSAN","suffix":""},{"id":637545828,"identity":"bdb3531f-1074-434d-ab4e-f0e859815e10","order_by":1,"name":"M. S. 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This study presents a controlled experimental investigation aimed at directly comparing multiple EB and NSM FRP strengthening configurations within a unified framework. Six full-scale RC beams (170 \u0026times; 260 \u0026times; 1600 mm) were tested under three-point loading. One beam served as a control specimen, while five beams were strengthened using different configurations, including EB CFRP laminates (soffit and side-bonded), a CFRP sheet, and NSM GFRP bars (single and double). All specimens were designed with identical geometry, internal reinforcement, material properties, and loading conditions to ensure a consistent basis for comparison. The study extends beyond conventional strength assessment by providing an integrated evaluation of structural performance, including load-carrying capacity, stiffness development, ductility, crack propagation, and energy absorption. The results showed that all strengthening techniques significantly enhanced flexural performance, with increases in ultimate load ranging from approximately 50% to 85% compared to the control beam. EB CFRP configurations exhibited superior strength enhancement, while NSM GFRP systems demonstrated more reliable bond performance and improved crack control. However, strengthened beams generally showed reduced ductility compared to the control specimen due to the nonlinear-elastic behaviour of FRP materials. The findings highlight the critical influence of strengthening configuration on overall structural behaviour and provide a comprehensive basis for selecting appropriate FRP strengthening techniques based on performance requirements. This work contributes to a more reliable understanding of configuration-dependent behaviour through a consistent experimental approach and a multi-parameter performance assessment.\u003c/p\u003e","manuscriptTitle":"Systematic Experimental Evaluation of EB and NSM FRP Strengthening Configurations for RC Beams: Strength, Ductility, and Failure Mechanisms","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-18 03:40:31","doi":"10.21203/rs.3.rs-9620259/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"75814738003553197884303947292929935182","date":"2026-05-10T03:44:21+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"164315036338541818913517438935346034120","date":"2026-05-10T03:08:19+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"330195082428699274234321552258091550388","date":"2026-05-08T06:51:26+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-05-08T02:22:39+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-05-08T02:21:45+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-05-07T13:59:23+00:00","index":"","fulltext":""},{"type":"submitted","content":"Asian Journal of Civil Engineering","date":"2026-05-05T14:50:03+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"asian-journal-of-civil-engineering","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Asian Journal of Civil Engineering](https://www.springer.com/journal/42107)","snPcode":"42107","submissionUrl":"https://submission.nature.com/new-submission/42107/3","title":"Asian Journal of Civil Engineering","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"0fee599e-eb59-43a4-afc1-143f16368ac8","owner":[],"postedDate":"May 18th, 2026","published":true,"recentEditorialEvents":[{"type":"reviewerAgreed","content":"75814738003553197884303947292929935182","date":"2026-05-10T03:44:21+00:00","index":15,"fulltext":""},{"type":"reviewerAgreed","content":"164315036338541818913517438935346034120","date":"2026-05-10T03:08:19+00:00","index":14,"fulltext":""},{"type":"reviewerAgreed","content":"330195082428699274234321552258091550388","date":"2026-05-08T06:51:26+00:00","index":13,"fulltext":""},{"type":"reviewersInvited","content":"9","date":"2026-05-08T02:22:39+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-05-08T02:21:45+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-05-07T13:59:23+00:00","index":"","fulltext":""},{"type":"submitted","content":"Asian Journal of Civil Engineering","date":"2026-05-05T14:50:03+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-18T03:40:31+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-18 03:40:31","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9620259","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9620259","identity":"rs-9620259","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}