The Effect of Prying Action Forces on the Design Methodology of Semi-Rigid Bolted Connections

In this study, the behavior of endplate connections with various rigidities has been investigated. After creating the finite element models, the model accuracy is evaluated using the experimental results. The maximum error of the finite element models generated is estimated to be around 8 percent. Through parametric analysis of semi-rigid connections, an important factor influencing the behavior of the connections is detected. The prying action is one of the most significant parameters in connection behavior; lack of attention to this phenomenon in the design phase will cause errors in calculation.
To calculate the prying action force in T-connections, two experimental methods exist. The computational method of Smith and AISC, the amount of computational error in the Smith method is 80 to 160 percent depending on the rigidity of the endplate connections. In the second method, AISC, in connection with semi-rigid endplate, the error is estimated to be about 40 percent.
To understand how to set the AISC formulation, models of the T-Connection with variable endplate thickness are made, and a parametric analysis was performed. The failure mechanism of these connections is shown that in connections with flexible endplates, much of the prying action force is created. In connections with very rigid plates, the effect of prying action forces can be neglected.
By comparing the stress distribution in flexible, rigid, and T-connections, the geometric coefficient of 3-row bolted endplate connections is considered 1.25 and in 2-row bolted 0.5. The maximum error of calculating the prying action force is about 5%. Using the improved method, in semi-rigid connections, the need to calculate the prying action and no need to calculate it is characterized. Having the exact amount of prying action forces, an improved design method has been authorized based on the philosophy and methods of allowed stress. In this method, a 22 percent reduction in design error has been