Calculation method for cracking shear capacity of steel reinforced concrete T-shaped column-steel beam spatial exterior connections

Employing the criterion of 'weak connection', ten steel reinforced concrete (SRC) T-shaped column-steel beam spatial exterior connections were designed and examined through low cycle reversed loading test, aiming at establishing a calculation model for predicting the cracking shear bearing capacity of the connections. The cracking patterns and shear crack locations of the connection core were obtained during the initial loading stage. Both the superposition principle and elastic theory were considered to calculate the cracking shear bearing capacity of the SRC T-shaped column-beam connection core. For the column embedded with soild-web steel, the shear contribution of the steel web was included into the calculation model via an equivalent area method. The results show that vertical bond cracks firstly appear along the concrete cover of the profiled steel in the SRC T-shaped column-beam spatial connections. After that, the shear cracks start to occur on the column limbs of the connection core. In addition, the location of the first diagonal crack is related to the loading angle. When the loading angle is less than 45°, the shear crack appeares in the column web of connection core; when the loading angle is 45°, the shear crack can be in the web or flange; when the loading angle is 60°, the shear crack appeares in the column flange of connection core. Based on the general tendency of the experimental phonmenon, when the loading angle changes from 0° to 45° and from 45° to 90°, the shear cracking calculation of the T-shaped column frame spatial connection limb should focus on the core web; and core flange, respectively. The theoretical shear cracking bearing capacity calculated by either the superposition principle or elastic theory is larger than the test results. The calculated values based on the elastic theory are closer to the experimental results when compared with the superposition principle method which can be more practical.