VolkerStevin Marine UK (VSM), a JV between VolkerStevin Ltd and Volker Stevin Construction Europe, was awarded the £25M D&C contract and were involved in gaining the various consents required under the planning conditions prior to undertaking the works on site.
The existing reinforced concrete jetty head was cut into sections and these were lifted off on to barges for recycling. The jetty support piles were cut to a level of 2 metres below the future dredge level.
The component parts of the new jetty were designed around the capacity of the crane Barge Dina M with the philosophy of manufacturing off site and minimising the works carried out on site.
The 150m long jetty approach consisted of a pipe and road bridge structure. Piles were driven to level and pre-cast concrete capping beams placed on each pair of piles. Steel road and pipe bridges were placed on these pre-cast units spanning up to 27 metres. Pre-cast slabs were then placed on top of the steel bridges to form the road access.
The jetty head was founded on 30No. piles with pre-cast concrete capping beams placed on the piles. Pre-stressed concrete beams spanned between these capping beams and the units stitched together with 530 m3 of in situ reinforced concrete.
Large 3.0m diameter piles weighing up to 100T each were driven for the berthing & mooring dolphins. These were driven using the Dina M and a large pile hammer to within 50mm of the specified tolerances.
We installed an induced current Cathodic Protection system to prevent corrosion and maintain the jetty's design life.Additional constraints included considerations for piling during the bird nesting season and monitoring of the cable tunnels that ran under the Medway.