Samenvatting

Multi-faceted tasks can be completed in a linear start-to-finish fashion, or by completing the different facets parallel to each other. Either way, at some point the final additions and adjustments are made such that all the pieces fit together, and the task is completed properly. For example, baking a cake requires a set of steps to be followed, but the final step will be putting the cake in the oven for a set duration and temperature. If this step is not followed correctly, the cake is ruined. The closure joint (CJ) of an immersed tunnel is the last piece that is installed that locks the entire structure together. Improper execution of the design and installation works of this component can result in loss of longitudinal locking forces – essential for tunnel watertightness – along the entire structure. To correct this would be an arduous endeavour. Therefore, the design of the closure joint is an important step in the process of building an immersed tunnel. However, the implications of the closure joint on the rest of the project are often overlooked.
There are several different types of closure joint, each suited to different situations. Some types are very pragmatic and rely on well know construction techniques while other more innovative types have been developed to deal with more complex project conditions. This chapter introduces the study, project setting and the scope of the research that is conducted in this document. A brief explanation of immersed tunnelling and closure joints is added to the background information provided in this chapter. More complete explanations are provided in the theoretical framework and appendix of this document.