River Hayne, Devon

The 120m long brick Culvert located on the river Hayne in Wilmington had sustained significant scour in several locations throughout and at either end in the riverbanks. This was identified and work was needed to protect the structure, so a team was mobilised to provide access and assist in the placing of Soluform bagged concrete ballast bags into the scour holes. We used 1 shift to set up, 8 shifts to complete the works and 1 shift to pack down. This was working with Mgroup operatives.

We mobilised our transit custom van with our fully electric Hoeflon tracked carrier, our Iveco 5m flatbed Truck and trailer and a 4x4 and crane trailer. The compound was a private yard suitable for the vehicles and trailers, with access down a grass hill and a walk roughly 50m away from the riverbank where we were to set up the pontoon walkway. We matted an area so we could use our tracked carrier to facilitate getting the 5x2m slabs of pontoon and edge protection gear to the riverbank as well as the materials and equipment for the works including the soluform bags. We set up and used our crane trailer in the compound to load the tracked carrier.

Once the pontoon sections were tracked to the riverbank, we launched them and assembled a walkway which was 12m long and 2 metres wide with a left turn towards the culvert 28m long and 2 m wide to provide stable direct access right to the entrance of the culvert from the riverbank. The walkway was fully edge protected and held in place with ropes and ratchet straps with safety equipment also available throughout. We deployed an operative in full water rescue PPE to check the culvert, identify the scour areas and set up safety lines and lights in the culvert for the works.

A 4x2 m pontoon was built to act as a barge to carry equipment and soluform bags through the culvert, starting at the far end and working back towards the pontoon walkway. We had 2 operatives on site for the works to change any pontoon as required, maneuverer the small barge around and act as safety cover in full water rescue PPE including drysuits and PFDs. We also had a Rigiflex 400 safety boat on site throughout the works complete with full safety kit and equipment to recover persons in the water.

For the demobilisation, the pontoon sections for the walkway were broken down into 5x2 slabs and our Jekko SPX 532 spider crane was used, with a capacity of 3.2 tonnes and a 14.3 metre max radius, light work was made of lifting each pontoon slab from the water and onto the tracked carrier. This was then used to track up the hill to the compound where the slabs were loaded onto the trailers with our crane trailer.