Poole Harbour - Upton Viaduct

A team was mobilized to carry out reactive inspection and repair works on steelwork brackets surrounding six columns at two locations beneath a bridge in Poole. Transport involved a 4x4, a crane trailer, and an Iveco flatbed truck with both pontoon and boat trailers, operated by three personnel. The bridge was accessible via a five-minute boat trip from the local marina. Because the work areas on the columns were located low down, operations relied on spring low tides. A shallow bar between the marina and the site further restricted access, requiring precise tidal interpretation to optimize working windows—a task aided by advanced navigational equipment carried on all our boats.

The 6m workboat was launched from a slipway, with the crane trailer used to lower and assemble pontoon slabs in the water. Using aluminium ramps and the 4x4, a one-tonne compressor was loaded onto the pontoon and secured. The team towed the assembled pontoon to the site a day prior to commencing works. At the first location, the pontoon fully encapsulated three columns, its shape adjusted as needed to accommodate various brackets and metalwork. Adjustments were made during the first low tide to ensure safety throughout tidal changes. Modular floats of varying sizes facilitated these modifications, and edge protection was installed. The pontoon measured approximately 14m by 5m, including sections shaped to avoid seabed obstructions, and was held in place using ratchet straps and rope. Due to low clearance at high water, the collapsible A-frame carrying lights and aerials on the boat were lowered allowing access under the structure.

Four early morning shifts were undertaken, scheduled around low tide to maximize productive time. Workers cleaned the metalwork with the compressor for engineers to inspect and repair, while safety cover and boat transfers were provided when tidal conditions permitted. The safety team conducted regular rescue drills and familiarized themselves with the area. Upon completing work at the first site, the pontoon was moved and re-secured at the second location where the pontoon was re-purposed. This allowed the workboat to shuttle engineers back to the initial site, enhancing efficiency.

Once the project concluded, the pontoon was towed back to the marina, where all equipment, including the compressor, was unloaded. The pontoon was then disassembled and lifted ashore using the crane trailer. The boat was recovered and transported back to the yard along with the rest of the mobilization gear.

In total: One shift for mobilization, four early morning work shifts, and one shift for demobilization.