In a letter sent to the…

In a letter sent to the proponent in July 2021m, the senior soil technician from the engineering firm hired by the proponent, submits new soil analyses for the 6 bore holes as an addendum to the previously issued geotechnical report completed by XXX Engineering, on February 16, 2021.
It contains recommendations and comments on pavement design information for the parking and travel areas.
Once again, the proponent, upon receiving this addendum, had ample opportunity to between July and now to have the engineering firm draw new samples from new boreholes on the current site location (amended on November 22, 2021) but he did not.
In this July letter, the soil technician states that "site grades will be raised approximately
1.14 m (3.74 ft) to 1.82 m (5.97 ft) above the existing grades in order to achieve a proposed
finished floor elevation of 179.50 m. The proposed footings will be designed to be constructed at elevations higher than the elevations indicated previously and structural fill will be required in order to achieve the design grades for the proposed foundations. He outlines the quality of the granular structural fill that will be needed. He also suggests that, as an alternative, lean mix concrete fill could be used.
Comment: Would this be the same granular structural fill as was suggested for the original site? or with the change in location, would a different type of fill be required?
The Senior Soil Technician states that, "When constructing new footings adjacent to existing footings, such as those from neighbouring buildings, all existing disturbed backfill material from the existing footing must be subexcavated to ensure that new footings are founded on approved undisturbed
soil. Any areas subexcavated to remove disturbed soils could be backfilled with mass
concrete. It is imperative that excavations do not extend below the existing footings or the
bottom of foundation walls without providing support to both the underside of the
foundation wall through shoring or underpinning, as well as support the foundation wall
structure itself (as designed by the structural engineer)
Comment: Who is going to oversee that these structural supports are done correctly?
the soil technician comments on the fact that the site classification for seismic response in Table 4.1.8.4 of the 2012 Ontario Building Code relates to the average properties of the upper 30.0 m of strata. The information obtained in the geotechnical field investigation was gathered from the upper 5.18 m to 8.23 m of strata.
Comment: Why was the Ontario Building Code classification of 30 m of strata not used on this site.? The bore holes ranged from 5.18 m to 8.23 m of strata.
He further suggests that structural engineer responsible for the design of the structure should review the earthquake loads and effects. Is Site Class D (Stiff Soils) appropriate for the new site plan.
For areas with existing brick and concrete surfaces, it is recommended that prior to placement of
the granular base/subbase materials, all brick/concrete be removed down to satisfactory subgrade
soils and the subgrade soils must be proof-rolled, and any soft or unstable areas should be
subexcavated and replaced with suitable materials. The subgrade should be graded smooth (free
of depressions) and properly crowned to ensure positive drainage, with a minimum grade of 3%
toward the catch basins or to the parking lot/driveway edge. When service pipes are installed, pipe
bedding and backfilling should be undertaken, as indicated in Sections 5.9 and 5.10 of the
previously issued geotechnical report.
In regard to sand parking and travel areas, it should be noted that the sand surface could become
very loose to loose if disturbed and may not maintain a solid structure throughout the year or during
high traffic situations. Once the sand surface is disturbed, ruts and loose areas will remain until
fully repaired. Repairing of the sand surface may be difficult during the winter months and the
sand surface may be required to be repaired very frequently during the typically busy summer
months depending on traffic volumes.
Comment: The whole issue of maintaining a permeable service for water drainage. Pavement in or around these buildings is not suitable. We have yet to see a storm management plan that will allow for proper water run-off from high precipitation, as happens regularly on this site.
Once again, the whole issue of paving and surfacing must be addressed based on the new site shared on November 22, 2021.