The Challenge

Our client, composed of a consortium of two major Canadian contractors, was tasked with the seismic upgrades of the Ladore Dam in Campbell River (BC). Part of the works consisted of the removal and installation of new spillway gates with a total weight of over 90 mT.

The challenging part consisted of maintaining the operability of the dam to ensure the continuous production of clean hydro power by BC Hydro. Needless to say, a disruption in the supply of energy would have been simply catastrophic to the electric grid servicing Vancouver Island and the Lower Mainland of BC.

The exercise was further complicated by the remoteness of the area, with an existing structure located between beautiful steep mountains and rocky slopes.

RSE was therefore tasked with the major marine temporary works for the Project, consisting of the mooring spread for an 80 x 80 ft barge, mounted with a 300 mT crawler crane, entrusted with lifting the heavy sections. The barge had to be anchored with long mooring lines with steep angles and anchored to rocky shores, guaranteeing the maneuverability required by the site team.

The Solution

RSE’s naval architecture and geotechnical team was therefore mobilized and tasked with the engineering of the detailed ballasting plan and step-by-step lifting plans for several loading conditions of the sectional barge, entrusted with the transfer of heavy elements from the shoreline to the spillway location.

RSE also designed anchor spreads and all of their components jointly with barge anchors to be drilled at the site into the rocky shores. The mooring points were designed by RSE with the necessity of accommodating several mooring angles and conditions.

Loads on the mooring spread were modelled through CFD scenarios, which were then used as input for the drag forces of the barge.

Finally, RSE was responsible for the ship-to-shore (STS) transfer of cranes and heavy material loading scenarios.

The Result

Multiple gates were replaced successfully, within the timeframe and working windows prescribed by BC Hydro, with minimal disruption to the operations and no blackouts.

RSE’s specialist and integrated knowledge of naval, structural and geotechnical engineering played a key role in providing timely, expert services as temporary works designer for the Project, guaranteeing the safety and constructability of all solutions envisioned in cooperation and close coordination with the Contractor at the site.

‍