9735

8979

كارشناسي ارشد

سازه

اصفهان: دانشگاه صنعتي اصفهان، دانشكده عمران

1393

هجده،131ص.: مصور،جدول،نمودار﴿رنگي﴾

ص.ع.به فارسي و انگليسي

داود مستوفي نژاد

94/1/22

كياچهربهفرنيا، مهرداد حجازي

مهندسي عمران

ID8979

Bond Slip Relationship of Grooving Method by Strain Analysis Using Particle Image Velocimetry PIV Mohsen Heydari Mofrad Mohsen heidary@cv iut ac ir December 13 2014 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language PersianSupervisor Dr Davood Mostofinejad Prof Email address dmostofi@cc iut ac irAbstractFiber Reinforced Polymer FRP composites are widely accepted as a promising and easy to use constructionmaterials especially for strengthening purposes due to the numerous advantages such as high tensile strength ease of application light weight and corrosion resistance One of the most common methods for flexuralstrengthening of concrete beams with FRP materials is the Externally Bonded Reinforcement EBR method The main problem that has greatly hampered the use of EBR method is the premature debonding of FRPlaminate from the beam substrate This will shorten the expected lifespan of the reinforced membrane andmakes EBR method uneconomical Near Surface Mounted NSM method is another flexural strengtheningtechnique for reinforced concrete structures The NSM technique can provide a significant increment of theload at serviceability limit state as well as the stiffness after concrete cracking In terms of the debondingissue experiments have shown that the NSM has a better performance compared to the EBR however delamination and debonding of FRP sheets from concrete is highly probable in both methods and stillremains as a limitation Recently special treatments on concrete surface prior to using the FRP sheets in theEBR technique named as Externally Bonded Reinforcement on Grooves EBROG and Externally BondedReinforcement in Grooves EBRIG has been introduced in Isfahan University of Technology IUT Iran The EBROG and EBRIG methods have shown a great promise in resolving the debonding problem Based onsome experimental investigations the EBROG and EBRIG methods can considerably postpone thedebonding and in some cases may completely eliminate it The aim of the current study is a study on CFRP to concrete joint which results of these studies is bond slip relationship for EBROG method To do so 48concrete prisms with dimensions of 150 150 330 mm were cast with three mix designs for three differentcompressive strengths In current study use CFRP sheets with 0 13 0 17 and 0 26 thickness and use twogrooves with 2 5 10 and 15 mm depth The specimens were strengthened using EBR and EBROG methods Afterwards all strengthened specimens were subjected to pull out test In order to benefit from full fielddeformation measurements a non contact image based technique i e Particle Image Velocimetry PIV wasused to investigate the bond behavior of tested specimens After the evaluation of results and use commonrelationship between strain shear stress and slip obtain relationship between shear stress and slip Then forbond slip relationship in EBROG and EBR methods a new function was been proposed The study resultsshowed that proposed function for EBROG and EBR specimens has good fitting with load slip and bond slipcurves Also according to experimental data in current study increasing in compressive strength concrete inEBR specimens and EBROG specimens with grooves depth equal 2 mm caused increasing in load capacity but in EBROG specimens with grooves depth equal 5 10 15 mm with increasing in compressive strengthconcrete the load capacity not an increased because the CFRP sheets in most of specimens were rapture andaccess final tensile capacity Increasing in CFRP sheets thickness in all specimens there was an increase inload capacity In EBROG specimens load capacity was increased by increase the depth to 10 mm increaseddepth of 10 to 15 mm will be a slight reduction in load capacity which due to the stress concentration aroundgrooves and local fracture in CFRP sheets Keywords FRP composites debonding single shear test bond slip model externally bonded reinforcement EBR groovingmethod GM Particle Image Velo

داود مستوفي نژاد

كياچهربهفرنيا، مهرداد حجازي