Robustness is a hard-to-grip concept within engineering. This master thesis uses a framework to quantify the level of robustness that has been proposed by the Joint Committee on Structural Safety to assess the influence of the reliability requirement of a structural element. The lock complex at Weurt (the Netherlands) has been used for a case study to calculate robustness indices for multiple values of the reliability requirement. In addition, the influence of redundant elements has been examined. Based on the results it can be concluded that increasing the reliability requirement of an individual element does not necessarily result in a higher level of robustness. In some cases a lower robustness index is found. Redundant elements, however, do increase the level of robustness.