Analysis of the block shear failure of structural steel members using the finite element method

Bracing elements, tension elements in lattice girders and roof trusses can be given as examples of elements under the influence of axial tensile force in steel structures. In the design of tension elements, calculation is made by taking into account the limit states of tensile yielding, tensile rupture and block shear rupture. These limit states apply to tension elements with both welded and bolted end connections. Block shear is a failure mode that determines the design strength of the connection. Block shear can occur on both the tension element and the plates used in the sections where the tensile force is formed at the ends of the bending elements with a moment connection, as well as in the connections where the shear force is transferred. The regulations recommend equations for estimating block shear strength. However, these equations may not always be able to predict with high accuracy. Limit state of block shear rupture is an important failure mode that must be controlled in areas where tensile force occurs in steel structures. Block shear is a limit state in which areas on the axis perpendicular to the force reach the tensile capacity, and areas on the axis parallel to the force reach the shear capacity. The geometry of the connection determines the shape of the block shear. In order to determine the block shear limit state capacity with the analytical models given in the regulations, it is necessary to perform calculations for all possible block shear paths and determine which is critical. The smallest of the strengths found for different paths of block shear gives block shear strength. This process greatly extends the design time. In addition, there is a possibility that the designer will miss some paths of block shear. In this thesis study, block shear failure occurring in bolted end connections used in steel structures was examined by finite element method. In addition, in order to verify the accuracy of the finite element method, bolted end connections are formed on S235 quality 4 mm thick plates and axial tensile test was performed on the plates. The obtained results were compared with the capacity equations used by the current regulations and experimental results.