A new 26-metre bridge was constructed to provide vehicular and pedestrian access between Montgomery Square and the new Wood Wharf development in Canary Wharf. RDG was involved in the initial phase of construction, which required the placement of steel casings for the foundation piles of the bridge.
Two cantilevered platforms were designed using RMD equipment to extend over the water to the exact location the piles were to be imbedded. The piling rig was positioned on a stabilised barge, positioned alongside the platforms in preparation for piling. Due to the proximity of the London Underground Jubilee line running below the waterbed, the position of the piles were fixed with no room for deviation. The design brief for both platforms was to provide a safe working platform suspended above the water level with a safe working load of 2.5 kNm-2. The platforms needed to be robust enough to resist impact from moving piling casings and the floating barge during installation.
The first of the two platforms was a straightforward cantilever design extending over the edge of the Montgomery St. wharf wall. Packing pieces were used to ensure the platform was level and precast concrete blocks were positioned at the rear to provide counter ballast.
The second platform required a more complex design due to the prescience of a perimeter secant pile wall that could not provide any support. Instead, an independent RMD structure was constructed to cantilever without resting on the wall, secured by an existing reinforced retaining wall at the rear. Due to pile casing cut off levels, the platform had to be positioned as low as possible which resulted in the underside of the platform skimming the top of the existing secant wall.
The platform was further modified to include pile locations to the sides as well as directly in front. The combination of using standard RMD frames and equipmentbecame challenging when large cantilever lengths were required with minimalincreases in platform thickness. This was achieved, providing a ‘tooth edge’profile cantilever platform extending 4.000m over the secant wall. Perimeteredge protection was provided to ensure the safety of the piling operatives.
