Behavior of reinforced concrete members with insufficient shear capacity strengthened with mechanical steel stitches, an innovative technique, under earthquake simulated cyclic loads

In this study, reinforced concrete cantilever beams with insufficient shear capacity were reinforced with mechanical steel stitches (MÇD/MSS). The study mainly focused on the study of the behavior of reinforced concrete cantilever beams with insufficient shear capacity reinforced with MÇD under the influence of reversible-repetitive cyclic loads. The effectiveness of reinforcement was investigated by applying 45° X-shaped MÇDs to each sample. Within the scope of the study, a total of 26 reinforced concrete cantilever beam samples, divided into 8 groups, were exposed to reversible and repetitive loads simulating earthquakes. In the experimental groups, the diameter of the MÇD, stirrup spacing, beam longitudinal reinforcement diameter, compressive strength of the target concrete, shear span/useful height ratio and height parameters of the reinforced concrete beam geometry were analyzed, respectively. The distance from the horizontal loading point to the top elevation of the foundation in the 1/2 geometric scale cantilever beams is 540 mm, 701 mm, and 1049 mm, respectively. The study could be part of a vision to develop innovative, practical and cost-effective solutions, especially for earthquake-active regions such as Turkey, where many reinforced concrete buildings have insufficient shear capacity. With the MÇD method, it can be ensured that existing structures offer a fast and less costly solution. Experimental results include load-displacement curves, stiffness values, cumulative energy consumption, and ductility values to enable a comparative evaluation of the structural performance of different samples. After analyzing the results of the experiments separately, the different results in each group were compared with each other and the experimental results were interpreted accordingly. As a result, it has been understood that the reinforcement method with 45° angled X-shaped MCD is an effective method of reinforced concrete cantilever beams with insufficient shear capacity under the effect of reversible-repetitive cyclic loads. This method offers a very effective solution to increase the cutting capacity and energy consumption performance of beams with a low a/d ratio. However, it is important to carefully evaluate parameters such as beam height and MÇD diameter during the application of this method.