Valve Installation Survey

AJT Engineering / Concept Development / Detailed Design


Cadherent were contracted to carry out an as built survey for an existing valve installation which was installed in a very remote location at a Hydro Dam Aqueduct. The valve was a 96” Diameter MIV (main intake valve) which was required to be replaced with a modern design. The replacement of this valve was extremely challenging due to restricted access, via a forest track to an elevated level and with no external lifting provisions for handling the 15-Tonne MIV.

Stage 1 - Site Survey

Following initial meetings, Cadherent mobilised 2x surveying teams to site. One team 3D Laser scanned the MIV installation inside the aqueduct building with a second carrying out a topographical survey for the access track from the station up to the aqueduct building. Additionally as the project developed a third survey was carried out on a specialist forwarder vehicle to ensure integration with a bespoke design handling cradle, for the MIV, in addition to checking turning areas and articulation level when moving up and down the forest track.

Stage 2 – Concept Development

As this project had a number of stages to lift and move the existing valve from location concept models and storyboards were prepared to allow for a clear understanding of the requirements and proposed solutions. This allowed for a number of client and sponsor inputs so all parties understood the replacement plan as due to the criticality of the valves duty a narrow timescale was provided for any system downtime.

Stage 3 – Detailed Design

Upon conclusion of the concept development detailed design was carried out for all required lifting and handling solutions for both the existing and replacement MIV`s, Additionally guarding and infill floor framing was provided to suit the new design MIV after installation. Support was provided for the fabrication of required steelworks packages in addition to sequential detailed story boards to further ensure no issues or particularly time delays.