# Experimental Study of Steel Reinforced Concrete (SRC) Joints
## 1 Introduction  
Steel reinforced concrete (SRC) joints, which are composed of reinforced concrete with a steel section embedded inside, are a relatively new structural solution. The joint is the weak point when experiencing seismic action. It is necessary to analyze whether adding reinforcement to this joint will allow it to absorb a large amount of energy to avoid the failure of structures. A higher ductility means greater energy absorption in the case of earthquakes, which increases the deformation that can be achieved without the collapse of structures. The Architectural Institute of Japan (AIJ) published the first regulation [1] in 1951 for designing steel reinforced concrete structures. In 1967, [PERSON] [2] carried out the first studies of steel reinforced concrete columns under bending and traction strength. The studies conducted since 1973 by [PERSON] [3], analyzed the behavior of SRC. This author presented a series of 10 tested cross-shaped specimens. The conclusion was that in terms of design, the method for superposition, which adds the individual resistance of steel, concrete and corrugated rods, was the most adequate for predicting the elastic behavior of a section. The steel cross-section can replace part of the reinforcing bars of reinforced concrete and it is able to dissipate greater energy than conventional reinforced concrete structures. [PERSON] and [PERSON] [4] studied the behavior of confined specimens subjected to static compression loads and to load-unload cycles to evaluate the degradation of reinforcement by verifying that the response was similar in both cases. [PERSON] and [PERSON] [5; 6] studied the rotation capacity of double T steel beams and column-beam joints by a local plastic mechanism. They devised computersoftware determine the rotation capacity of beams, which they compared with experimental tests to obtain consistent results. In these studies, standard beams were used in two types of structures: continuous steel beams and rigid frameworks. [PERSON] et al. [7] conducted different studies with joint steel reinforced concrete. The results show that SRC joints efficiently dissipated energy. The superposition method was able to accurately estimate joint strength. The research conducted by [PERSON] et al. [8] analyzed the behavior of reinforced concrete steel beams using cross-sections in H. In her thesis, [PERSON] [9] analyzed reinforced concrete supports strengthened with steel cross-sections. She performed a thorough literature review in the field of reinforced concrete supports. Reinforcement with L-cross-section steel improves the resistance and ductility of the element, which is a satisfactory solution for reinforcement concrete structures to improve their behavior when experiencing earthquakes. In his thesis, [PERSON] [10] studied the buckling behavior of rectangular tubular steel cross-sections filled with high-strength concrete under an axial load using a variable bending movement diagram. [PERSON] et al. [11] investigated over 17 specimens with different solutions of steel cross-sections for concrete. They were composed of L or T steel cross-sections with reinforced concrete. Their force-displacement graphs are comparable to other numerical studies carried out, such as those by [PERSON] et al. [12], who analyzed the hysteretic curves and introduced the attenuation coefficient to represent the effects of seismic damage. They proposed a model that considers seismic damage and compared the model of hysteretic curves with experimental ones. [PERSON] et al. [13] used a conventional test frame with a loading-unloading cycle. Recent research, such as that of [PERSON] and [PERSON] [14], have shown that high-strength reinforced concrete structures, confined with tubular cross-sections and embedded steel cross-sections, display the best behavior. In this paper, the main failure modes of columns were caused by bending. The latest break occurred in the beam cross-section next to the joint, which is where most of the bending stress is absorbed.