Steel structures

A joint can be considered an assembly of several components which individually have their characteristic strength, stiffness and deformation capacity. Such a joint is a combination of “springs”. Combining these springs will result in the overall behaviour of the whole joint. This so-called “component method” is the basis of the design of joints in Euro code 3. Simplified and more sophisticated spring modelling can be assumed. In scientific context the sophisticated spring model is available. However, there is an urgent need for such models in framework programs for use in practice. The use of the simplified model leads to iterations to determine the correct distribution of moments in the structure. For steel structures, the development of new types of joints among these “plug and play” joints need a boost to meet the goals described in the introduction. Ideas for these joints need theoretical and experimental research before these joints can be applied in practice. The philosophy for using these joints is that in the early erection phase the joints are plug and play, resulting in joint behaviour that is sufficient for the loading conditions in the erection phase. When the access of the joints is better because of the presence of parts of the floor system, the joints can be finalized by adding bolts resulting in the final mechanical behaviour needed for the loading conditions in the final stage of the building. Semi-rigid and partial strength design consideration will also lead to substantial economic advantages in the detailing and fabrication of the joints. The flooring structure should be as light as possible before finalizing the joint in the end-stage of the building process, such as thin-walled profiled sheeting for composite slabs or steel-board flooring systems. But, it is also possible using prefabricated thin concrete slabs on which the final concrete floor is poured without props in the end-stage of the building process. The columns can be continuous or bolted at floor level, just underneath the floor finishing. Further creativity is needed to develop “plug and play” type joints which can be considered as finalized once the beams are remotely controlled positioned and connected to the columns.