satisfaction of the City Drainage Superintendent or the Consulting Engineer. As part of the work, the Contractor will be required to clean out the drain along the full length of the pipe and for a distance of 3.05 metres (10 ft.) upstream and downstream of the pipe. The Contractor shall note that the pipe inverts are set at least 10% of the pipe diameter (or the pipe rise) below the drain bottom to provide the embedment required by E.R.C.A. and D.F.O. and to meet the minimum cover requirements for the pipe.
The installation of the complete length of the new culvert pipe, including all appurtenances, shall be completely inspected by the City Drainage Superintendent or the Consulting Engineer’s Inspector prior to backfilling any portions of same. Under no circumstance shall the Contractor commence the construction or backfill of the new culvert pipe without the site presence of the City Drainage Superintendent or the Consulting Engineer’s Inspector to inspect and approve said installation. The Contractor shall provide a minimum of two (2) working days’ notice to the City Drainage Superintendent or the Consulting Engineer prior to commencement of the work. The installation of the new culvert structure is to be performed during normal working hours of the City Drainage Superintendent and the Consulting Engineer from Monday to Friday unless written authorization is provided by them to amend said working hours.
For the access bridge installations, once the new culvert has been satisfactorily set in place, the Contractor shall completely backfill same with granular material M.T.O. Type “B” O.P.S.S. Form 1010 with the following exception. The contractor is to ensure that backfilling occurs on both sides of the culvert simultaneously, or so that the fill on one side of the culvert does not exceed 500mm (19.7”) to the other side of the culvert. For road crossings the top 450mm (18”) and for residential driveway the top 300mm (12”) of the backfill material for the full top width of the access, and the full top width of the drain or the excavated trench, and any approaches shall be granular material M.T.O. Type “A” O.P.S.S. Form 1010. All of the approach areas extending over the new bridge culvert shall be backfilled with compacted granular material M.T.O. Type “A” O.P.S.S. Form 1010, but only after all topsoil material has been completely removed and disposed of, and the minimum thickness of this granular material shall be 450mm (18”) for roadways and 300mm (12”) for driveways. All areas outside of the access shall be backfilled with native material compacted to 95% of Standard Proctor Density and topped with a minimum of 100mm of topsoil, and shall be seeded and mulched.
For hard surface roadway and driveway crossings, the contractor is to ensure that no backfill exceeds 300mm (12”) per lift. Additionally, at roadways the top 450mm (18”) and at driveways the top 300mm (12”) of the backfill over the pipe below the hard surface treatment shall comprise granular material M.T.O. Type “A” O.P.S.S. Form 1010 compacted to a minimum of 100% Standard Proctor Density. The Contractor shall at all times be very careful when performing its backfilling and compaction operations so that no damage is caused to the pipe. To ensure that no damage is caused to the proposed pipe, alternative methods of achieving the required backfill compaction shall be submitted to the Consulting Engineer or the City Drainage Engineer for their approval prior to the commencement of this work. The Contractor shall restore the asphalt surface by placing a minimum of the existing thickness, using materials as shown in the schedule of items and prices or notes on the plans, or a 90mm minimum thickness of Type HL-4 hot mix asphalt or Superpave equivalent. The asphalt shall be supplied and placed in two (2) approximately equal lifts compacted to a value ranging from 92% to 96% of maximum relative density as per O.P.S.S. 310. For existing concrete driveways, the Contractor shall carefully remove the concrete to the nearest expansion joint. The concrete shall be restored to the original length and width that was removed and include 150mm thick, 30mPa concrete, with 6% ±1% air entrainment and 6x6-6/6 welded wire fabric reinforcing installed at the midpoint of the slab. All slab surfaces shall be