This is a service / maintenance or supply contract in Mississauga, Ontario. Contact the soliciting agency for additional information.

Reference Number 0000290516 Question Acceptance Deadline 14-Apr-2025 12:00:00 PM EDT Metrolinx is accepting Submissions for the provision of “Construction Administration Services – Retaining Wall & Oil Grit Separator at Streetsville Bus Garage”. The retaining wall and adjacent curb located at the south perimeter of the bus facility are exhibiting an accelerated rate of settlement and displacement. The abutting curb and gutter have sunken and horizontal movements in some locations have caused a large gap between the curb and the wall. The retaining wall is vital to ensure the structural integrity of the roadway around the perimeter of the facility, which is required for bus movement and temporary parking storage. The retaining wall does not meet the ideal engineering 1.5 Factor of Safety (FOS), determined during the stability analysis by a consultant and could further deteriorate under actual surcharge from parked buses. Parking adjacent to the retaining wall has been temporarily suspended until the deficiencies have been addressed. If deterioration is left unmitigated the retaining wall may collapse causing injuries, property damage, and delays to operations and maintenance activities required at the Streetsville Bus Facility. An engineering consultant was tasked with further investigating the cause and extent of retaining wall dislocation and conducting a replacement/rehabilitation feasibility study. The study consisted of retaining wall settlement monitoring, and geotechnical investigation (borehole data and global stability analysis). The retaining wall is being pushed towards the drainage swale by lateral pressures from both the infill soil and surcharge loading from parked buses for extended periods. The movements in the wall are a result of a combination of settlement, sliding and rotational actions near the base of the wall. The accelerated rate of deterioration is a result of lack of subdrains at the back of the retaining wall that causes build-up of hydro-static pressure behind the wall and frost susceptibility. The removal and replacement of the existing retaining wall with a new pre-cast retaining wall is recommended to mechanically stabilize the earth and incorporate sufficient drainage behind the base of the wall to mitigate the build-up of water and hydrostatic pressure. Stormwater management and ground improvement are required to address the causes that attributed to the accelerated asset failure. The work will also include installation of new concrete and PVC storm sewers and new infiltration trenches. Furthermore, oil contaminants were found to be pooling in the drainage swale at the toe of the retaining wall and are being discharged directly into the adjacent receiving Mullet Creek system. The existing water quality strategy requires attention as the infiltration trench is not adequate for treating oil and petroleum in the stormwater runoff. Given the complex site servicing, four individual oil and grit separator ("OGS") units are required to treat runoff from individual catchment areas. Since the stormwater strategy includes outlet pipes through the retaining walls OGS units should be installed at the same time as the retaining wall works to minimize construction costs. Metrolinx reserves the right to reject any or all Submissions at its sole discretion. Official bid documents must be obtained from www.metrolinx.merx.com and bid submissions must be done through the Merx platform.