استفاده از روش شيارزني به جاي آماده سازي سطحي متداول جهت جلوگيري از جداشدگي صفحات تقويتي FRP در برش

چكيده انگليسي :

Grooving as a Substitute of Surface Preparation to Postpone Debonding of Shear Strengthening FRP Laminates from Concrete Surface Amirhomayoon Tabatabaei Kashani a tabatabaei@cv iut ac ir Date of Submission April 21 2011 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisors Dr Davood Mostofinejad dmostofi@cc iut ac ir Adviser Dr Mohamadreza Eftekhar eft@cc iut ac ir AbstractIn the last part of this thesis a practical analytical model that is applicable in commoncommercial softwares to simulate the elastic and inelastic behavior of reinforced concretebeam column joints is presented A data set of 20 planar interior beam column joints isused to evaluate the analytical models Results of comparative analysis with analyticalmodels show their capability in simulation of linear and nonlinear behavior of reinforcedconcrete beam column joints By comparing the numerical analysis and experimentalresults a good conformity between the results was achieved The main feature of theanalytical model is their applicability in reinforced concrete frames for a more accurateassessment of response and behavior of new or existing structures One of the methods ofretrofitting reinforced concrete structures is use of FRP sheets to increase the flexural and shearstrength of concrete elements Use of FRP materials is in rapid progress because of their highstrength light weight and easy installation of FRP composites Poisson s ratio mismatch betweenFRP sheets and concrete is resulted premature debonding of FRP strips Surface preparation forbeing connected to the sheets can delay debonding to some extent This separation however hasbeen evidenced in most studies in reinforcement concrete beams have been strengthened by FRPsheets On the other hand preparing the surface of concrete suffers from such limitations as lossesdue to pause in work expensiveness and even lack of access to the member involved Therefore inthe current study the effect of preparing the surface for shearing strength of reinforcement concretebeams and replacement of this method by grooving will be investigated The experimental specimen included 20 beams of 560 85 80 mm and 48 beams of 560 85 70mm and covered 11 series subjected to four point loading An attempt was made to delay flexuralfailure of beams through longitudinal and mechanical anchorages so that it would be possible tocompare the increase in the shearing capacity of the beams resulting from the use of differentmethods in installing FRP strips The beams used in each series include control beams thestrengthened without surface preparation with surface preparation and with grooving method Theresults of the study showed that surface preparation before installation of FRP strips can increasefailure load to a small extent when compared with specimen without surface preparation However the debonding of FRP strip from concrete surface still occurs This method increases shearcapacity and can also increase ultimate load of beams up to 12 percent On the other hand Comparison between the ultimate load and deflection of the test beams demonstrates that groovingmethod was effective and led to elimination of debonding of FRP strips used for shearstrengthening This method increases mid span deflection and also increase ultimate load ofbeams up to 19 percent Key WordsSurface preparation grooving strengthening shearing reinforcement reinforced concrete FRPcomposites

طباطبايي كاشاني، امير همايون

استفاده از روش شيارزني به جاي آماده سازي سطحي متداول جهت جلوگيري از جداشدگي صفحات تقويتي FRP در برش

مقاوم سازي , تقويت برشي , بتن آرمه