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>

The trend of offshore wind power is bigger and bigger wind turbines. Turbines are now becoming so big that existing installation vessels no longer are feasible and new bigger installation vessels are needed. Ship owners hesitate to order new vessels worried that the rapid turbine growth will continue and make also the new vessels obsolete in a few years. This can create a bottleneck in the offshore wind market.   This thesis assignment attempts to develop a telescopic tower as an alternative way of installing offshore wind turbines. A telescopic tower can decrease overall height and COG during marine installation, giving opportunity to install the largest wind turbines also with existing vessel fleet.   The method for developing the telescopic tower is to first find the main problems and functions of the concept. A design basis based on a 12 MW reference wind turbine is developed. Based on this reference turbine different solutions to the main problems and functions are developed by creative thinking, literature research, modelling, calculations and analysis. A cost/benefit analysis is performed to investigate if there is any economic potential in the developed solution. To complete the study other installation methods and telescopic tower concepts are investigated for benchmark comparison.   The telescopic tower will have two sections. Shoulders are welded to the inner wall of the lower tower. The upper tower fit inside the lower tower and a telescopic mechanism is installed below to lift the assembly as the mechanism climb the shoulders of the lower tower. The telescopic mechanism works much like a pin and hole mechanism used for jack-up rigs. The pins engage/disengage with the shoulders by the movement of linear actuators. The vertical climbing motion is provided by hydraulic cylinders. The power source is an HPU placed on the wind turbine external platform.   To connect the upper and lower tower permanently a friction connection with long slotted holes is used. This connection is developed for assembly of onshore towers in an EU-sponsored project called Histwin. The walls of the lower and the upper tower overlap at the connection and are pressed together by pretensioned bolts to create a friction surface that hold the loads from the upper tower.   The conclusion is that the telescopic tower is technically feasible and can be installed by the existing installation vessel fleet. The economic feasibility is dependent on the specific project characteristics, but there are scenarios where the telescopic tower can have great economical upside.