Design Problems for Existing Dry Dock Gates for Graving Docks and Trends to be Followed in Design of Mitre Type Dock Gates

Abstract

Dry dock is a structured zone wherein construction, repairs and maintenance of merchant vessels and boats are carried out. Presently, in India, there are so many docks which are under both private control and as well as Indian Navy control, which have their gates in their life end states and are still being operated under very unsafe conditions. In this regard, Indian Navy has recognized to replace most of the dock gates with new state of the art design and most modern type of gates. A modern dry dock gate, when compared to its predecessors, differs significantly in terms of dimensions, materials, construction and sophistication of equipment; but the basic principles of operation and design remain the same. Every dock gate has its own set of operational parameters which include the important parameters such as (i) entrance width, retained water height, tidal range, speed of operation, weight limitations, seismic resistance, vessel impact, vehicle loading and reverse hydrostatic loading. Material of construction and advances in materials and methods of construction have continually expanded the dimensional limits of dry docks and as well as their gates. In this paper, the authors have particularly emphasized the design problems for the existing gates and new technologies and methodologies to be adopted in the selection and design of the new gates for the existing dry docks while replacing the existing gates. The procedural approach and methodology to be followed for selection of different types of gates such as Caisson Gates, Flap Gates and Mitre Gates etc., have been emphasized in this technical paper.