Contract Value: £1.5m
CMP Thames were contracted on a one to one basis to carry out the upgrade works to the existing RO-RO facility by constructing the new berthing and mooring dolphins together with associated walkways, these works were carried out in order to extend the existing RO-RO berth thus enabling the use of larger capacity vessels.
The 8m x 6m Berthing dolphin consisted of 8no. 914mm o/d x 20mm wall thickness x 51m long steel tubular piles (36m+15m) driven to a rake with a 2.3m thick cast insitu RC capping complete with a 200 tonne capacity mooring bollard and a hung fender panel system.
The 6m x 6m Mooring dolphin consisted of 6no. 914mm o/d x 20mm wall thickness x 51m long steel tubular piles (36m+15m) driven to a rake with a 2m thick cast insitu RC capping complete with a 125 tonne capacity twin quick release mooring hook and capstan.
The works were carried out utilising two crane barges 1 x 250tonne + 1 x 120 tonne capacity crawler crane.
Four temporary piles where driven vertical for each dolphin and the topped with prefabricated frames for the temporary permanent pile support works, once the temporary works were in place a framed prefabricated steel top deck inclusive of soffit and raking tubular pile support sleeves was fixed in position.
Each pile was installed at a rake of 1:3 and in two pieces 1 x 36m and 1 x 15m, with the 36m length driven first and the 15m length was then welded insitu with a full strength butt weld, the butt welding was carried out at night and weekends to minimise the delay to the daily piling output.
The soft start piling methods were adopted with the initial drive carried out using a hydraulic vibrating hammer and the final drive using a hydraulic drop/impact hammer.
Once the piles had been installed the RC dolphin deck was cast in two parts, firstly a 600mm thick deck slab to form the soffit then the remaining 1.700m thick deck was cast. Concrete was pumped from the end of the RO-RO pontoon to each of the two dolphins over a maximum distance of 260m.
Walkways and all fittings and fixtures where added.