Hull Marina is accessed by vessels from the tidal River Humber by two pairs of radial sector gates operated by electrically powered winches. Each gate leaf is of steel fabricated egg-box construction bolted to radial arms which transfer the hydraulic loads into top and bottom pivot brackets and subsequently into the civil structure.
The objective of the maintenance works was to refurbish the existing two pairs of lock gates to ensure they are fully operational on completion. The refurbishment consisted of the replacement of the hinge pins/bushes, a complete set of gate seals a full set of sacrificial anodes.
Initially, Kaymac had to design, supply and install the necessary temporary works equipment including stoplogs and all necessary pumps, pipework, sandbags, access ladders, etc. to enable safe working within the lock basin in the dry. To achieve this, the lock pit and both sets of gates were isolated from the hydraulic effects of the River Humber and the impounded water of the marina by the installation of the bespoke steel stop logs which locate into channels integrated into the civil structure at the extreme ends of the lock pit. Prior to the installation, it was necessary to clean the submerged stop log chases on both west and east side of the lock adjacent to both the inner and outer gates by divers. Once the chasers were cleared of any debris or marine growth, the stoplogs were installed using a crane within the compound. The enclosed area could then be dewatered by pumping to provide a reasonably dry working area in order for the refurbishments to take place.
We encountered a number of challenges during the project, one of which was the amount of silt in the lock pit. As a result of being in the Humber estuary the silt had migrated into the lock, once the lock was dewatered, a vast amount of silt sat the bottom of the lock and around the working area. We did not let this affect our program; using the crane we lowered an excavator into the lock pit, excavated and manually moved the silt away from the gates to allow clear working area. It was also identified that the outer stop logs were leaking significantly; to overcome this we installed fly ash to the leaks seal that worked effectively and remained dry for the duration of the works.
The works were successfully completed, along with additional works all within the program. On completion the gates were tested to ensure they are fully operational prior to handing back to the Client.
A video of the project can be found on our YouTube Channel.