Connection Design for Easy Assembly On-Site. Method to Design and Evaluate Structural Connections in Industrial Construction

Today, on-site production is a common construction technique in building industry, which can be inefficient regarding cost and production time. Therefore an industrial construction process is needed. Building industry should both be flexible in order to meat the users’ demands and at the same time keep a low production cost. Knowledge could be gained from manufacturing industry which, during a long tradition of industrial processes, has developed several design methods in order to standardise the way of thinking. This master’s project concerns connection design with focus on assembly, therefore methods concerning assembly were studied in order to see if they could be adjusted and used in building industry. In addition to the methods, guidelines from building industry were investigated. An obvious difference between manufacturing industry and building industry is the size of products and parts; the whole assembly will be larger in building industry. Production in manufacturing industry is also performed in a suited location, which is unusual for building construction. During the study, different demands on design methods were found; a design method should for instance be complete, systematic, measurable and user-friendly. With the knowledge from the studies, a four step iterative design method for structural connections in industrial construction was developed. The method starts with guidelines aimed to help the designer develop connections which are easy to assemble. Next, design proposals, which should be investigated with help of the method, have to be described with comments and figures. Then absolute demands, depending on the design situation, are controlled using a checklist. A connection must for example withstand design loads. The next step is an evaluation regarding the connections’ assemblability, consisting of criteria divided into three statements. A grade is calculated for each criterion depending on the studied connection’s performance and the criterion’s importance. The result of the evaluation is a mean grade and an assembly index for each connection. A case study has been performed in order to improve the method and it has shown that the evaluation method works satisfactory. The last step of the method concerns reduction of unnecessary parts. When using the design method an iterative procedure is recommended. It is important to stress that assemblability is one aspect among many which have to be considered during a design process. However, assembly has a major impact on the total production process and was therefore chosen to be the focus in this project.