Experimental study on impact resistance of damaged reinforced concrete beams strengthened with CFRP
The drop hammer impact tests were carried out on reinforced concrete beams with different damage degrees strengthened with carbon fiber reinforced polymer(CFRP).Taking the impact height and the number of reinforcement layers as the test parameters,the crack development,failure mode and impact resistance of the damaged specimens strengthened with CFRP were analyzed and the dynamic performance of the specimens under impact load was studied.The results show that the higher the damage degree of the specimen,the denser the oblique crack development and the more serious the damage degree of the specimen.The higher the drop hammer impact height is,the closer the crack development is to the mid-span localization.When the damaged specimens are strengthened with multi-layer CFRP sheets,the specimens maintain good integrity under the impact of drop hammer,and only the external concrete is crushed and dropped.With the increase of the number of CFRP layers,the whole specimen produces bending and shear failure.Compared with the unreinforced specimen,the impact resistance and stiffness of the damaged beams are significantly improved with the increase of the number of CFRP layers,and the improvement amplitude is 70%-72%.However,increasing the number of CFRP layers has limited effect to improve the reinforcement and repair effect of the specimen,and the reinforcement effect is not linearly related to the impact resistance.Based on the results of effective strain calculation,it can be seen that the use of CFRP reinforcement not only has the role of reinforcement,but also can improve the overall impact resistance of the specimen to a certain extent.
CFRPreinforced concrete beamreinforcement and repairdrop hammer impactdynamic responseimpact resistance
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