Investigation of impact behaviour of shear deficient reinforced concrete beam to column connection strengthened with CFRP strip

Reinforced concrete (RC) structural members may be subjected to the effect of impulsive dynamic loads due to reasons such as explosion, rockfall, erosion, landslide, vehicle crash to the bridges of highway or seaway, in their service period. Therefore, it is an important issue to investigate the impact behavior of the column-beam joints of the frames constructing the bearing system of the reinforced concrete structures and also to consider these effect in the design stage. In the scope of the thesis study carried out, the impact behavior of RC beam-column joint strengthened with CFRP strips has been experimentally investigated. For that purpose, the eight 1/3 scaled RC column-beam joint elements of which shear strength is insufficient has been manufactured. RC beam-column joints were cast as monolithic and composed of the column part with the dimensions of 200x200x1200 mm and beam part with the dimensions of 100x150x1500 mm that was located to the center of the column part. The concrete of which 28-day compressive strength is 25 MPa and the rebars with the diameters of 6 and 8 mm has been used for the manufacture of test specimens. Before the strengthening procedure, the bottom and side surfaces of test specimens were roughened with a width of 50 mm and the spacing of 150-250 mm. The CFRP strips with a length of 400 mm and the width of 50 mm have been wrapped using Sikadur 330 to these prepared surfaces. Impact load was applied to test specimens using the drop-weight test setup. Two different input impact energies were applied to test specimens by dropping steel hammer with a weight of 84 kg from two drop-heights of 500 and 750 mm. The time-histories of impact loads, accelerations and displacements measured from test specimens and strains of CFRP strips were recorded in the experiments. The effects of the experimental variables on these dynamic responses recorded have been examined and the impact behavior of RC column-beam joint strengthened with CFRP strips has been interpreted with of results obtained.