There are many Dams around the Lower Mainland to maintain as a part of the Metro Vancouver potable water supply. Often these areas are remote and access is a challenge. As they are a part of the potable water system care needs to be taken to ensure no contaminants make their way from the dam surfaces to the downstream river that supplies the treatment facilities before being piped to the reservoirs for distribution throughout the lower mainland.
Seymour Falls Dam
Seymour Dam is situated inside one of the watersheds for Metro Vancouver’s freshwater supply. Our job was to replace the transverse deck joints to minimize leakage through the bridge deck.
Another aspect of the work was removing and reinstalling anchor plates and bolts on the dam itself. For this work, we relied on Pacific Ropes High angle rope access. They were able to install over 700 plates and bolts without the need for scaffolding, or crane access. The most efficient use of available deck space and funds.
Cleveland Dam is at the south end of Capilano Lake and is a popular walking/hiking for locals and provides 40% of the drinking water for Metro Vancouver.
This project has a number of challenges that our team needs to overcome. Not the least of which is access. The job required us to waterproof the interior and exterior walls with a cementitious material with the goal of keeping water in the spillway from entering the concrete walls which would increase the deterioration of the concrete.
MCR will be partnered with Pacific Ropes; a high angle rope access company, to access areas that were unreachable or more economical than by crane.
To ensure there was no contamination of the river downstream we erected bulkheads at the end of the flip bucket to create pools that were able to be then disposed off apart from the river.
At the other end of the water infrastructure within Metro Vancouver is the sewerage system. Many of these structures are also concrete and sewer gases have a deleterious effect on concrete, and therefore require repairs. The challenge with these structures is more about keeping our crews safe in an inhospitable environment and making sure that all the procedures and equipment are in place to ensure a successful project including the health and safety of all our crew members.
Annacis Island WWTP
Annacis Island WWTP is one of the sewage treatment plants in the lower mainland. Metro Concrete Restoration won the bid to re and re the concrete in each of the 13 pre-aeration tanks at this facility. Each tank is covered, thereby trapping H2S gas between the effluent water and the covers. The H2S gas reacts with the exposed concrete creating sulphuric acid which degrades the cement paste. The nature of the work required us to work in a confined space and a biohazard work environment
The work required us to use hydro demolition to remove the degraded concrete. Once the sound substrate was exposed, there were thousands of dowels that needed to be installed before reinstating concrete to achieve not only good cover but a sacrificial layer as well to hopefully ensure these tanks last for the foreseeable future.
Another concrete structure is the Highbury Interceptor that is on the Metro Vancouver side of the Iona WWTP. This space required mitigating the biohazard, working in a confined space, while continuing to monitor the flow in the upstream pipe to ensure water levels didn’t exceed the capacity of the open two siphons.
We have been involved in a variety of water reservoir projects around Metro Vancouver. Many of these projects focus on increasing the waterproofness of the structure to ensure minimal leaking around joints. As with dams, these structures are a part of the potable water system of Metro Vancouver and great care needs to be taken on anything being brought into the reservoir to ensure there is no contamination.
Combi flex is a common choice to increase the water tightness of the joints in reservoirs. Sika’s Sikadur-Combiflex® SG system is a modified flexible Polyolefin (FPO) waterproofing tape that spans the open joint and provides a flexible joint to allow movement as needed while maintaining a bond to the concrete substrate.
Metro has worked on and around marine environments many times to date. These marine projects can provide unique challenges including getting access to remote sites and protection of sensitive environments. Each marine project has required its own special approach and we are proud of the practical solutions we have provided.
Spruce Harbour Marina
Spruce Harbour Marina is a private facility owned and operated by the Greater Vancouver Floating Home Co-op located in downtown Vancouver. One of the access bridges to the marina was badly cracked and damaged. This project required us to remove the existing hollow core panel via crane and replace it with a new hollow core panel. This project had many complications including location, dealing with tides and necessary support work.
Concrete Ships in Powell River
Powell River is home to nine Concrete ships, dating back to WW 1. All of the ships have a unique story of glorious days gone by, either as cargo or transport vessels during the wars. The Peralta is the largest in the group, dating back to 1921 and weighing in at 3,696 tons.
In the summer of 2009, extensive repairs to the exterior of the PerAlta were carried out to make it safe for cleaning and ultimately sinking as it was the oldest ship and in the worst condition. Currently, this repair appears to be holding up well with very little delamination of the repair noted. The repair program allowed the Per Alta to go from the ship in the worst shape, to one in the best shape. As a result of this change in status, the YOGN was now deemed to be the best candidate to reduce the footprint of the breakwater and become an underwater reef. The sinking of YOGN occurred in June 2018 and now sits on the ocean floor just off shore in the Powell River area.