A steel frame structure of a few storey building is considered in European project FRAMEUP. Each column of the building is constructed from steel profiles connected by column-to-column connection, called column splice. In FRAMEUP project new type of column splice connection is designed to facilitate assembly. This connection consists of a plate, called finger plate with characteristic shape of holes, called long open slotted holes. A column splice with long open holes is a type of friction connection, where finger plate transfer load between bottom of one column and top of a second part and preloaded bolts are used to clamp segments together. In this work, the behaviour of the connection is investigated. Moreover, general information about column splices, friction connection and loss of pretension are introduced in literature review. A recommendations, for the preloaded bolts are investigated in accordance with European standard EN 1993-1-8. An experimental static compression tests are performed in order to observe the real behaviour of the column splice with long open slotted holes. Several number of numerical tests are performed to predict behaviour of the connection by use of Abaqus software. The Numerical model is validated against experimental results. Further tests are performed in order to check an influence of other important factors on the behaviour of connection system. An influence of connection geometry i.e. filler plate thickness, characteristic of the surface and the material properties are analyzed. The variation of bolt forces as well as slip factor and reduction factor ks are investigated. Finally, experimental test and finite element method analysis are discussed and conclusion are given. / <p>Validerat; 20140913 (global_studentproject_submitter)</p>