Finite elements analyses of bolted stiffened end plate beam-column connections

Ductile design of beam - column connections is as critical as ductile material used in steel structures so that it can provide ductile behavior in the steel structures. Structure behavior subjected to earthquake is significantly affected due to brittle failure of the connections. Structural damages, which are occurred by 1994 Northridge and 1995 Kobe Earthquakes, caused review for the concept of ductile connections in the structures. Therewith, the SAC Steel Project team has determined principles of the beam-column connections which has been offered as multiple and reliable by the team. In this thesis, the stiffened endplate connection types which are advised from FEMA 350 and included in Turkish Building Earthquake Codes. In the beginning for the understanding of bolt behaviours, the single lap connections are investigated first. Thereby, whether results obtained by using finite element method and experimental studies are compatible or not is scrutinized. Moreover, various bolt-hole size and behaviours of bolts are researched. It is observed that the finite element analyse results and experimental results are compatible each other and the applied finite element techniques are valid. Techniques obtained from single lap connections is used for stiffened end plate connections. The geometry and material properties of the finite element models are obtained a study from literature. The loading procedure of the corresponding study is considered. The finite element models derived from literature study by adding different features such as not to supporting beam laterally or transverse bending on the beam flange caused by welding applications. Nonlinear effects of materials, geometry and contacts are considered, for all finite element models. It is observed that the rigidity of the single lap connections decreases by increment of the bolt hole size. The maximum stresses are observed in the bolt holes which are nearest to applied forces in the tension member. Moreover, it is observed that the frictional contact between plates can be ignored when the bolt diameter and bolt-hole diameter are equal. Similarly, for the stiffened end plate connections, the highest tension forces are observed in the outer bolts in the end plates. The plastic hinges are occurred approximately same region which is the place where end plate ends. Transverse bending in the beam flange caused by welding process can reason loss of rigidity in the build-up sections and these losses are order of approximately 1%. However, not to supporting the beam in a lateral way can cause approximately 6% loss of rigidity.