Behavior of Glass FRP reinforced concrete beams having Carbon FRP sheets stirrups

Abstract

Steel corrosion is the biggest problem which is responsible of deterioration structures and reduces the virtual age of concrete structures and increasing in the cost of maintains specially hydraulic structures and structures exposed to harsh environment condition. Fiber Reinforced Polymer (FRP) bars, have been gaining momentum as alternatives to traditional steel reinforcements in structural civil engineering sectors . FRP are non-corrosive, lightweight, non-conductive making them a good alternative to steel bars in aggressive environments. The brittle behavior up to failure of FRP bars, made it can‟t bent to make stirrups. So that, the innovative alternative manner two ways by using CFRP sheets for the first time without resin to make stirrups and by use CFRP sheets strips immerged by sika dur330 instead of steel stirrups to produce beams reinforced purely with FRP by a new manner provided stirrups in different sizes and with lower cost. In present research, twenty one RC rectangular beams with three percentage of primary reinforcement (seven beams for each ratio). Three beams as control beams with steel stirrups: two beams designed to fail by shear. While, the other eighteen beams were divided into two groups: nine beams with CFRP sheets strips immerged by sika dur330 and the last nine beams with CFRP sheets strips without resin which designed by proposed equation. Change in amount and type of shear and amount of longitudinal reinforcement were the mainly variable. All beams tested under four points loading and under static conditions. Result of test showed that beams with higher amount of longitudinal reinforcement and shear reinforcement showed increasing in carrying load capacity 38.1% for CFRP sheets strips immerged by sika ii dur330 stirrups and 21% for CFRP sheets strips without resin stirrups compared with control beam. However, equivalent amount calculated from proposed equation showed increasing in ultimate load 10% for CFRP beams with sika dur330 and decreased about 10% for CFRP sheets without resin. While, beams with CFRP sheets immerged by sika dur330 stirrups showed ultimate load higher than related beams with CFRP sheets stirrups without resin. In maximum percentage of CFRP sheets immerged by sika dur330stirrups showed change in failure mode from shear to flexural failure observed by crushing in concrete cover. Furthermore, changed cracks orientation, increased energy absorption, increased concrete tensile and decrease principal strain. While, beams with CFRP sheets without resin stirrups with maximum amount of shear reinforcement don‟t changed failure mod and cracks patterns. In addition, the brittle failure mod were the dominate scenario. Finite element modeling by use ANSYS packages were used to validate experimental work result. Precisely, by comparing result achieved from finite element modeling with experimental result values, the accuracy of modeling were calculated. The difference between the predicted carrying load capacity verse mid-span deflection and experimental test result were less than 8%.