Standardization of Mitre Gates: Standardizing steel mitre gates within existing navigation locks in the Netherlands

The Dutch Ministry of Infrastructure and Water Management (Rijkswaterstaat) currently manages 137 navigation locks. Most of them have been constructed during the 20st century and were considered as unique projects. This led to a great variety in their designs and characteristics. Currently, 52 locks are reaching the end of their technical life span and require significant renovation and renewal. Almost all locks are different and this variety complicates their management and maintenance. These complications cause several problems concerning sub-optimal availability, unpredictable reliability and high life cycle costs. Rijkswaterstaat performed several studies, indicating that the standardization of lock gates could potentially solve these problems. However, how to standardize these lock gates is still unclear. This research investigates the standardization possibilities with the aim of reducing the variety found in lock gates, focusing on the mitre gates present in 37 of the 52 locks requiring large renovation and renewal. Focus is put on mitre gates as these are the most common gate type used in Dutch navigation locks. The approach of reducing the variety in the lock gates is based on the creation of clusters, in which one standardized gate is applied. The clustering of the mitre gates is based on the widths and required door heights of the considered locks. To tackle the problem of standardizing gates in locks with different widths, it has been decided to vary their angle of closure. The degree to which the angle of closure can vary is dictated by physical boundaries, indicating the limit with respect to stability requirements. Consequently it was chosen to modularize the doors so that they can be scaled up or down to the desired height, solving the problem of applying a standard door in locks with different retention heights. To grasp the effects of standardization, the over-dimensioning is approximated by using estimates for the amount of material required for the gates. To determine the optimum cluster configurations, a clustering program has been developed, taking into account both over-dimensioning and physical boundaries. The clustering program encompasses the study of 37 locks. This study shows that the gates of these locks can be grouped into a minimum of five clusters. Due to a modular gate design and fewer spare components, excessive over-dimensioning is prevented. A conceptual design and a comparative analysis indicated that the gates can best be grouped into eight clusters, potentially leading to improved management and a € 7.100.000 cost reduction. This research included several assumptions and starting points. The following steps should be taken in order to deepen and enhance the current research: • Assess the influence of the determining aspects on the costs of a lock gate instead of the material required. • Better approximation of over-dimensioning by using a more complex and accurate model for the estimation of the required material. • Perform a study on the amount of spare components required for each separate gate cluster.