Investigation of the impact behavior of reinforced concrete beam-column joints with varying shear reinforcement

Reinforced concrete structures may expose to sudden dynamic impact loads such as terrorist attacks or military blasts, crashes of the highway or sea vehicles, the collision of masses with the effect of landslide, flood or rockfall. Extensive literature review showed that the number of research work on reinforced concrete (RC) structures or structural members, which are subjected to impact loading, is limited. In this study, an experimental work was carried out to examine the behavior of outer column-beam connections under sudden dynamic impact loading. For that purpose, 16 samples were produced 1/3 scaled and RC column-beam joint elements that 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 tested beam-column specimens were designed to have two different concrete compressive strength, and four different shear reinforcement. In addition, structures were tested under three different height of drop. The drop weight was kept 84 kg for all experiments and an average concrete compressive strength of 10 and 25 MPa for 28 days. The height of drop for specimens with concrete compressive strength of 10 MPa was 500 mm and 750 mm whereas the height of drop for specimens with concrete compressive strength of 25 MPa were selected to be 750 and 1000 mm. In this study, shear reinforcement detail used in construction of beam elements was varied. The beam elements were constructed utilizing four different shear reinforcement detail. One specimen was built without shear reinforcement. For the remaining three specimens, spacing of shear reinforcements were 75, 150, and 300 mm. For all sixteen beam-column specimens, column elements with dimensions of column had same properties. The parts of beam-column specimens were casted at the same time. The produced samples were subjected to weight drop test. In this study, the results of the experiments were analyzed by considering the parameters shear reinforcement spacing, concrete compressive strength, and the drop height. The behavior of beam-column specimens was scrutinized through accelerations, impact load, displacements, shear and flexural cracks have been recorded in experiments. As a result of the study, it was observed that the tip acceleration, the tip displacement, and the crack widths reduced when the shear reinforcement spacing was reduced.