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Farhi Holdings Corporation
Building Tower and Parking Garage 435 Ridout Street North London, Ontario
Draft Geotechnical Engineering Report
Date: April 5, 2017
Ref. N°: 160-B-0016783-1-GE-R-0001-0A
Unit 12 – 60 Meg Drive, London (Ontario) Canada N6E 3T6 – 519..685.6400 | F 519.685-0943 – [email protected]
Farhi Holdings Corporation
Building Tower and Parking Garage 435 Ridout Street North
London, Ontario
Geotechnical Engineering Report | 160-B-0016783-1-GE-R-0001
Prepared by: DRAFT
Stephen W. Burt, P.Eng.
Consulting Geotechnical Engineer
Reviewed by : DRAFT
Colin J.W. Atkinson, M.Sc., P.Eng.
Senior Consulting Geotechnical Engineer
TABLE OF CONTENTS
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DRAFT GEOTECHNICAL ENGINEERING REPORT – BUILDING TOWER AND PARKING GARAGE, 435 R IDOUT STREET NORTH, LONDON, ONTARIO
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INTRODUCTION ............................................................................................................................................. 1
1 INVESTIGATION PROCEDURE ............................................................................................................ 2
1.1 Field Program ...................................................................................................................... 2 1.2 Laboratory Testing .............................................................................................................. 2
2 SUMMARIZED SUBSURFACE CONDITIONS .................................................................................... 3
2.1 Building tower (Boreholes 1 to 8) ........................................................................................ 3 2.2 Parking Garage (Boreholes 9 to 17) ................................................................................... 4 2.3 Atterberg Limits ................................................................................................................... 5 2.4 Summarized Groundwater Levels ....................................................................................... 5
3 DISCUSSION AND RECOMMENDATIONS ......................................................................................... 6
3.1 Excavations and Groundwater Control ............................................................................... 6 3.2 Earth Shoring ...................................................................................................................... 7 3.3 Building Tower Foundation Design ..................................................................................... 7 3.4 Parking Garage Foundation Design.................................................................................... 8 3.5 General Foundation Recommendatiosn ............................................................................. 9 3.6 Seismic Site Classification ................................................................................................ 10 3.7 Slab on Ground Construction ............................................................................................ 10 3.8 Lateral Earth Pressures and Site Drainage ...................................................................... 11 3.9 Flexible Pavement Design ................................................................................................ 11
4 STATEMENT OF LIMITATIONS .......................................................................................................... 12
Tables
Table 1 - Atterberg Limits Test Results .............................................................................................................. 5
Table 2 - Summarized Groundwater Levels ....................................................................................................... 5
Table 3 – Building Tower Highest Foundation Founding Levels ........................................................................ 7
Table 4 - Pile Types and Capacities ................................................................................................................... 8
Table 5 – Parking Garage Highest Foundation Founding Levels ....................................................................... 9
Table 4 - Pavement Design .............................................................................................................................. 12
Appendices
Appendix 1 Drawings
Appendix 2 Boreholes
Appendix 3 Figure 1
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Property and Confidentiality
“This engineering document is the property of Englobe Corp. and, as such, is protected under Copyright Law. It can only be
used for the purposes mentioned herein. Any reproduction or adaptation, whether partial or total, is strictly prohibited without
having obtained Englobe’s and its client’s prior written authorization to do so.
Test results mentioned herein are only valid for the sample(s) stated in this report.
Englobe’s subcontractors who may have accomplished work either on site or in laboratory are duly qualified as stated in our
Quality Manual’s procurement procedure. Should you require any further information, please contact your Project Manager.”
Farhi Holdings Corporation
484 Richmond Street, suite 200
London, Ontario N6A 3E6
Attention: Mr. Shmuel Farhi, President
REVISION AND PUBLICATION REGISTER
Revision N° Date Modification And/Or Publication Details
0A 2017-04-05 Draft Report Issued
DISTRIBUTION
1 electronic copy Client
1 electronic copy Architects Tillmann Ruth Robinson Inc.
1 electronic copy File
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DRAFT GEOTECHNICAL ENGINEERING REPORT – BUILDING TOWER AND PARKING GARAGE, 435 R IDOUT STREET NORTH, LONDON, ONTARIO
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INTRODUCTION
Englobe Corp. (Englobe) was retained by Farhi Holdings Corporation to perform a
Geotechnical Investigation at 435 Ridout Street North, London, Ontario, shown on the Location
Plan, Drawing 1 in Appendix 1.
It is proposed to construct a 32 storey building tower and a three level parking garage as
shown on the Site Plan, Drawing 2 in Appendix 1. The purpose of this investigation was to
determine the subsurface conditions at the site and, based on that information; provide
geotechnical recommendations for the design of foundations and pavements.
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1 INVESTIGATION PROCEDURE
1.1 FIELD PROGRAM
The fieldwork for this investigation involved drilling 17 boreholes from March 7th to 14th, 2016 at
locations shown on the Site Plan, Drawing 2 in Appendix 1.
The boreholes were advanced to sampling depths of 6.6 to 17.2 metres (m) using power auger
machines equipped with conventional soil sampling equipment, which were supplied and
operated by a specialist drilling company.
Soil samples were recovered from the boreholes at frequent intervals of depth using a 50 mm
O.D. split spoon sampler in accordance with the Standard Penetration Test (SPT) procedure.
The SPT N-values are shown on the borehole logs in Appendix 2.
Groundwater observations were carried out in the boreholes during and upon the completion of
drilling operations. The observations are summarized on the appended borehole logs and in
Table 2.
The fieldwork was monitored throughout by a member of our engineering staff who directed the
drilling and sampling procedures, documented the soil stratigraphies, and cared for the
recovered soil samples.
The level of the ground surface at each borehole location was related to a local benchmark,
which was taken as City of London Vertical Control Monument V92-22. This benchmark is
described as a nail set in the top of the southeast corner of a concrete wall around a ventilation
grill in front of the London and Regional Art Gallery on Ridout Street, and is located 40.0m
north of the centreline of Dundas Street and 25.0m west of the centreline of Ridout Street.
The benchmark was assigned a geodetic Elevation of 246.18m, as shown on the City of
London web site.
1.2 LABORATORY TESTING
All soil samples recovered during this investigation were returned to our laboratory for visual
examination as well as moisture content determinations. The moisture content test results are
shown on the appended borehole logs.
Additional Geotechnical laboratory testing carried out on selected soil samples are listed
below:
Two grain size analyses (MTO LS-702) (ASTM D422-63) with test results presented
graphically on Figure 1 in Appendix 3; and,
Three Atterberg Limits tests (LS 703 and LS 704) with test results presented in Table 1 and
the respective borehole logs.
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The soil samples will be stored for a period of three months from the date of storage. After this
time, they will be discarded unless prior arrangements have been made for longer storage.
2 SUMMARIZED SUBSURFACE CONDITIONS
Refer to the borehole logs in Appendix 2 for descriptions of the soil stratigraphy, results of SPT
testing, moisture content values, and groundwater observations. The following notes are
intended only to amplify this data.
2.1 BUILDING TOWER (Boreholes 1 to 8)
The proposed building area is located on the east embankment of the Thames River floodplain
that overlaps an existing building built into the hill, which is to be demolished. An older building
located at the top of the hill is to be incorporated into the new building tower.
Boreholes 1 to 4 were located at the top of the slope. Boreholes 1 to 3 revealed a surface
layer of asphalt, measuring 80 to 100mm thick, supported by 100 to 350mm of granular base
material. Borehole 4 revealed a 300 mm thick surface layer of topsoil. Beneath the topsoil and
pavement materials, Boreholes 1 to 4 encountered layers of dense to loose sand and gravel fill
materials displaying moisture contents ranging from 4 to 9%. The fill was penetrated at a
depth of about 10 m in Borehole 4, located just east of the building built into the hill, and at
depths of 1.4 to 2.9 m in Boreholes 1 to 3. Based on previous work carried out on this site, it is
known that the existing embankment was cut at an angle of 60 degrees to the horizontal and
the east wall of the building built into the hill was designed as a retaining wall, which was
backfilled with granular material. It is considered that Borehole 4 was extended through the
retaining wall granular backfill material.
Boreholes 5 to 8 were located near the toe of the slope, where Boreholes 5, 6 and 8 revealed
surface layers of topsoil measuring 300 mm to 1.4m thick. The topsoil sample in Borehole 5
yielded a moisture content of 27%. Beneath the topsoil, Boreholes 6 and 8 encountered layers
of soft to stiff silty clay fill displaying moisture contents of 12 to 36%, and the fill was penetrated
at depths of 1.0 to 2.1 m. Borehole 7 revealed a 120 mm thick surface layer of asphalt
supported by 880mm of granular fill.
Within Boreholes 1 to 8, the underlying soil consists of layers of stiff to hard silty clay to silty
clay/clayey silt till, compact to dense silt and sand materials, and dense to very dense silt and
sand till materials. The silty clay to clayey silt strata displayed natural moisture contents
ranging from 8 to 27%, the silt and sand layers displayed values of 18 to 20%, and the silt and
sand till displayed values from 7 to 12%. The boreholes were terminated within hard silty clay
to clayey silt till and very dense silt and sand till materials at depths of 6.6 to 17.2 m.
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The grain size distribution analyses test results; plotted on Figure 1 in Appendix 3; indicate that
the sand sample tested from Borehole 4 contains 67% sand 30% silt, and 3% clay.
The surface layers of topsoil revealed at Borehole 5, 6, and 8 locations, are identified as
potential sources for the generation of methane gas.
2.2 PARKING GARAGE (Boreholes 9 to 17)
The proposed parking garage is located at the top of the slope along Queens Avenue with
access ramps encroaching onto an existing slope down to the floodplain of the Thames River.
Boreholes 9, and 12 to 17, were located at the top of the slope, and Borehole 9 revealed a
300mm thick surface layer of topsoil. Boreholes 12 to 17 revealed surface layers of asphalt,
measuring 75 mm thick, supported by 200 to 800 mm of granular base. Beneath the
pavement, Boreholes 16 and 17 revealed layers of loose sand fill and silty topsoil that were
penetrated at depths of 2.4 and 0.9 m respectively. The sand fill sample from borehole 16
yielded a moisture content of 15%. In Boreholes 12 to 15, the pavement is underlain by layers
of silt, sand and cinder fill materials with fragments of brick, asphalt, concrete, glass and wood.
This fill was penetrated at depths of 8.5 to 11.5 m and it displayed moisture contents ranging
from 3 to 27%. Beneath the fill, Boreholes 12, 13 and 14 contacted layers of topsoil and loose
organic silt or marl displaying natural moisture contents of 23 to 34%, and these layers were
penetrated at depths of 11.6 to 13.0 m.
Boreholes 10 and 11 were located near the toe of the slope and beneath the surface layer of
topsoil, measuring 100 mm thick, Borehole 11 encountered loose silt and sand fill. This fill
displayed moisture contents of 11 and 28% and it was penetrated at a depth of 2.1 m.
Within Boreholes 9 to 17, the underlying soil consists of layers of firm to very stiff silty clay,
very stiff to hard silty clay to clayey silt till, loose to very dense silt, sand and gravel materials,
and dense to very dense silt till materials. The silty clay to clayey silt strata displayed natural
moisture contents ranging from 3 to 24%, the layers of silt, sand and gravel materials displayed
values of 6 to 21%, and the silt till displayed values from 7 to 12%. The boreholes were
terminated with hard silty clay to clayey silt till, very dense silt till, and dense to very dense
sand and gravel materials at depths of 6.6 to 17.2 m.
The grain size distribution analyses test results, indicate that the sand sample tested from
Borehole 13 contains 5% gravel, 83% sand, and 12% silt.
The surface layers of topsoil revealed in Boreholes 9, 10, and 11, and the buried topsoil and
organic clayey silt materials in Boreholes 12, 13, 14, and 17, are identified as potential sources
for the generation of methane gas.
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2.3 ATTERBERG LIMITS
Atterberg Limits tests were carried out on samples of the silty clay and the silty clay till
materials, and the test results are summarized in the following table.
Table 1 - Atterberg Limits Test Results
BOREHOLE
NUMBER
SAMPLE
ELEVATION
(m)
WATER
CONTENT
(%)
PLASTIC
LIMIT
(%)
LIQUID
LIMIT
(%)
PLASTICITY
INDEX
(%)
SYMBOL
04-17 234.2 22 18 36 18 CL
05-17 229.1 19 15 30 15 CL
08-17 230.5 19 13 24 11 CL (till)
The Atterberg test results indicate that the samples tested is clay of low plasticity. The moisture
content values of the silty clay samples range from 3 to 24%, which are drier than to wetter
than the measured plastic limits. The moisture content values of the silty clay till samples
range from 8 to 22%, which are drier than to wetter than the measured plastic limit.
2.4 SUMMARIZED GROUNDWATER LEVELS
The following table lists the groundwater levels measured in the open boreholes at the time of
the field work, and inferred levels of permanent saturation based on the change in colour of the
subsoil from brown to grey.
Table 2 - Summarized Groundwater Levels
Borehole
Measured Groundwater Level
During Drilling Depth (m) / Elevation
Brown/Grey Interface Level
Depth (m) / Elevation
01-17 Dry and Open 3.0 / 243.5
02-17 Dry and Open 3.7 / 242.9
03-17 Dry and Open 3.7 / 243.0
04-17 10.0 / 236.6 10.0 / 236.6
05-17 5.5 / 227.6 3.7 / 229.4
06-17 7.6 / 228.7 3.7 / 232.6
07-17 Dry & Open 2.9 / 232.1
08-17 3.7 / 229.3 3.7 / 229.3
09-17 Dry & Open 3.5 / 242.6
10-17 4.2 / 228.7 2.9 / 231.1
11-17 3.0 / 230.0 2.9 / 230.1
12-17 9.3 / 233.1 10.4 / 232.0
13-17 9.6 / 232.8 10.0 / 232.4
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Borehole
Measured Groundwater Level
During Drilling Depth (m) / Elevation
Brown/Grey Interface Level
Depth (m) / Elevation
14-17 13.1 / 230.3 13.0 / 230.4
15-17 13.1 / 230.6 13.0 / 230.7
16-17 Dry & Open 4.5 / 240.6
17-17 Dry & Open 3.0 / 242.3
3 DISCUSSION AND RECOMMENDATIONS
3.1 EXCAVATIONS AND GROUNDWATER CONTROL
The pavement, fill, topsoil, marl, firm to stiff silty clay, the silt and sand till materials, and the
layers of silt, sand and gravel materials revealed on this site which are not excessively wet can
be classified as Type 3 soil in accordance with the Occupational Health and Safety Act and
Regulations for Construction Projects. Saturated and submerged fill and non-cohesive soil
(silt, sand and gravel materials) shall be classified as Type 4 soil. In the absence of
groundwater seepage, the intact very stiff to hard silty clay to clayey silt till may be classified as
Type 2 soil.
The sides of open excavations within a Type 3 soil must be carried out using side slopes not
steeper than 1 vertical to 1 horizontal from the bottom of the excavation. Type 4 soil may be
dewatered to be classified as Type 3 soil, or adequately braced, otherwise side slopes of 1
vertical to 3 horizontal or flatter will be required for excavations intersecting Type 4 soil. The
sides of excavations within Type 2 soil may be sloped at 1 vertical to 1 horizontal above the
1.2 m near vertical cut.
Based on the borehole findings, it is estimated that the water table level within open
excavations at this site is approximated by the groundwater levels revealed within the sand and
gravel materials in Boreholes 10, 11, 14, and 15, between Elevations 229.7 and 230.6.
However, due to the low permeability characteristics of the silty clay and organic silt materials,
water can be found at higher levels perched within layers of fill and sand and gravel materials,
as demonstrated by Borehole 4, 12, and 13.
It is anticipated that groundwater and surface water entering open excavations may be
controlled by gravity drainage and filtered pumps up to 1.0 m below the groundwater table.
Lowering the groundwater table by more than 1.0 m within sand and gravel deposits will
require a permit to take water and a temporary dewatering system installed by a specialist
dewater contractor. Where groundwater seepage or sloughing from seams and layers of silt,
sand and gravel materials is occurring, it will be necessary to flatten the excavation side slopes
in order to ensure stability or be adequately braced.
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The hydraulic conductivity of the sand and gravel materials will vary depending on their texture
and, based on the gradation analyses test results shown on Figure 1 in Appendix 3, it is
estimated to be in the order of 10-2 to 10-4 cm/sec.
3.2 EARTH SHORING
For new structures constructed adjacent to property lines and existing buildings, particular care
will be required to minimize loss of ground or settlement on the adjacent properties and below
existing structures. Use of soldier piles and lagging or a continuous caisson wall may be
utilized in areas where there are no buildings or structures to provide adequate support. In
order to minimize the amount of vibration and loss of ground during the installation, a
continuous caisson wall should be utilized next to structures sensitive to disturbance.
Providing adjacent land owners give approval, lateral support can be achieved by the use of
permanent or temporary tiebacks; otherwise a temporary internal bracing system will be
required before permanent support is provided by the floor slabs.
Prior to construction, pre-condition surveys of existing adjacent infrastructure and/or structures
should be carried out. Inclinometers and/or monitoring points may also be installed and
monitored to determine if displacements of buildings or shoring systems occur.
3.3 BUILDING TOWER FOUNDATION DESIGN
It is proposed to support the building tower with a raft foundation. All pavement, fill, topsoil,
loose soil, and the firm to stiff soil, must be removed from new raft foundation area, and the
following table provides the highest founding levels at Borehole 1 to 8 locations where the
approved native subgrades will provide a maximum serviceability limits states (SLS) design
pressure of 240 kPa (5,000 psf).
Table 3 – Building Tower Highest Foundation Founding Levels
BOREHOLE
HIGHEST EL. / DEPTH FOR A
SLS DESIGN PRESSURE OF
240 KPA (5,000 PSF)
01-17 242.7 / 3.8 m
02-17 242.7 / 3.8 m
03-17 243.6 / 3.1 m
04-17 235.8 / 10.7 m
05-17 231.6 / 1.5 m
06-17 234.8 / 1.5 m
07-17 233.5 / 1.5 m
08-17 230.4 / 2.6 m
For ultimate limit states design, factored geotechnical resistance values of 335 kPa (7,000 psf)
may be used, where the resistance factor is equal to 0.5.
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3.4 PARKING GARAGE FOUNDATION DESIGN
It is proposed to construct a 3 storey parking garage featuring slab on grade construction.
Extensive amounts of environmentally impacted fill materials were revealed in the area
represented by the locations of Boreholes 12 to 15. A deep foundation system may be
installed to support the slab on grade structure. Due to the native subgrade consisting of
saturated and submerged sand and gravel materials, it is considered that installation of a
caisson foundation system is not feasible.
It is therefore recommended that a deep foundation system consist of driven steel piles and the
use of 12BP53 and 12BP74 H-piles (imperial units) are considered more suitable than tube
piles to achieve penetration into the the dense to very dense subsoil. The pile tips should be
protected with a driving shoe (OPSS 3301) or rock point to avoid damage to the lower section
of the piles.
The following maximum serviceability limits states (SLS) design loads may be used for pile
design.
Table 4 - Pile Types and Capacities
TYPE OF PILE SLS DESIGN LOADS
KN KIPS
12BP53 H-pile (imperial) 832 187
12BP74 H-pile (imperial) 1155 260
For ultimate limit states design (ULS) a factored geotechnical resistance value equal to 1.2
times the SLS design load may be used where the resistance factor is equal to 0.4.
For the 12BP53 and 12BP74 H-piles properly connected to the pile cap, the estimated
horizontal resistance of the piles is 75 kN at Ultimate Limit States and 25 kN at Serviceability
Limit States per pile.
The minimum driving energy for the H-piles shall be 35,000 J (26,000 foot pounds) per blow,
and it is anticipated that the piles will reach a suitable set once driven 5.0 to 8.0 m into the
dense to very dense subsoil. To avoid damage to the piles, refusal should be considered as 5
blows of an adequate hammer producing a total penetration of 6.0 mm (0.25 inches). Care
shall be taken to determine any displacement uplift due to driving of nearby piles, and in cases
where uplift is measured the pile must be re-driven to its original set. Total settlement of the
pile foundation is estimated to not exceed 10 mm.
The actual penetration and pile set characteristics will be dependent on the load carrying
capacity of the pile and the driving equipment used by the contractor, and the contractor should
therefore submit the pile hammer data for review by the geotechnical engineer.
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Alternatively, levels of underground parking may be provided by removing the fill and organic
clayey silt and founding the structure on conventional spread footings. However, this may
involve extensive groundwater control requirements in the area represented by the locations of
Boreholes 11 to 14 where the competent native subgrade was encountered at and below the
measured groundwater levels, particularly at Borehole 13 location where heaving sand was
revealed. Furthermore, additional environmental sampling and testing may be required in the
area represented by the location Borehole 12 to 15 locations prior to removal of fill from the
site.
For conventional spread foundation design, the following table provides the highest founding
levels at Borehole 9 to 15 locations where the approved native subgrades will provide a
maximum serviceability limits states (SLS) design pressure of 240 kPa (5,000 psf).
Table 5 – Parking Garage Highest Foundation Founding Levels
BOREHOLE
HIGHEST EL. / DEPTH FOR A
SLS DESIGN PRESSURE OF
240 KPA (5,000 PSF)
09-17 244.6 / 1.5 m
10-17 233.1 / 0.8 m
11-17 229.9 / 3.1 m
12-17 228.7 / 13.7 m
13-17 228.7 / 13.7 m
14-17 228.7 / 13.7 m
15-17 231.5 / 12.2 m
16-17 242.0 / 3.1 m
17-17 243.0 / 2.3 m
3.5 GENERAL FOUNDATION RECOMMENDATIONS
In order to minimize the disturbance of soil subgrades it is recommended that foundation
excavations be carried out using a smooth-blade bucket. The founding subgrade shall be
covered with a mat of 20 MPa concrete to protect the integrity of the subgrade from
disturbance due to ponding water and/or construction activities.
Where required, the approved native subgrade can be raised to a higher founding level by
placement of 20 MPa concrete or constructing engineered fill consisting of imported OPSS
Granular ‘A’ material. Engineered fill must extend outside the foundation area for a minimum
horizontal distance equal to the depth of fill placed below the footing founding level. The
engineered fill shall be placed in maximum 200 mm thick lifts, and each lift must be compacted
to a minimum of 100% of the materials maximum standard Proctor dry density (MSPDD) under
the full time inspection and testing of the geotechnical consultant.
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To provide sufficient protection against heave due to frost action, all exterior footings and
footings in non-heated areas must incorporate a minimum depth of soil cover of 1.2 m between
the footing subgrade and the finished ground surface.
3.6 SEISMIC SITE CLASSIFICATION
The borehole findings and laboratory testing results indicate that the ground on this site can be
categorized as Site Class D in accordance with Table 4.1.8.4.A of the 2012 Ontario Building
Code.
3.7 SLAB ON GROUND CONSTRUCTION
All topsoil, organic, wet, soft, frozen and otherwise deleterious materials must be removed from
the ground surface, and the subgrade shall be proof-rolled with vibratory roller. Spongy zones
revealed during the proof-roll shall be subexcavated. Subexcavated zones, low-lying areas,
and interior foundation trench excavations shall be backfilled with approved granular pit-run
material compacted throughout to a minimum of 98% MSPDD.
It is recommended that concrete floor slabs be constructed on a minimum 200 mm thickness of
19 mm clear crushed stone or Granular ‘A’ material compacted to 100% MSPDD. To minimize
shrinkage cracking and curling of the slab, the top of the floor slab must be kept moist as the
concrete cures.
To prevent the migration of moisture vapour into the building from beneath ground floor slabs,
particularly where moisture sensitive floor coverings are placed, a vapour retarder shall be
placed directly beneath the floor slab that meets the requirements of the designer and flooring
manufacturer. Prior to installing moisture sensitive floor coverings, the moisture content of the
concrete slab must be determined at operational conditions by internal relative humidity testing
to ensure an acceptable slab moisture content. It should be noted that it typically takes more
than 90 days at operational conditions to lower the slab’s internal relative humidity to 85%.
Different flooring systems have different responses to slab moisture (i.e. some systems can
tolerate more moisture than others), and the flooring contractor must assess the floor moisture
levels with respect to their flooring components.
Concrete slabs exposed to freezing temperatures should be provided with 50 mm thick rigid
Styrofoam insulation below the slab in order to prevent differential settlements from frost heave
and thaw settlement. All weather exposed concrete shall have 5 to 8% air entrainment or as
otherwise specified in Tables 2 and 4 of CSA A23.1.
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3.8 LATERAL EARTH PRESSURES AND SITE DRAINAGE
In the design of retaining walls with rigid lateral support, the lateral earth pressure will increase
uniformly with depth, and the pressure, p, at any depth, h, can be calculated with the equation:
p = Ko (γh+q)
where Ko = earth pressure coefficient at rest, 0.5
γ = unit weight of backfill, 22.0 kN/m3 (140 pcf)
q = effective value of any surcharge acting close to the wall.
The above expression assumes level grades beside the wall and the backfill consisting of free-
draining granular material with a drainage tile placed at the footing level to prevent the build-up
of hydrostatic pressures behind the wall.
For non-rigid retaining wall design, the coefficient of earth pressure may be reduced to 0.35.
Buildings with the floor levels at or above the surrounding ground surface and the ground
surface sloping away from the building will not require perimeter tile drains. Basement or pit
areas will require a perimeter tile drain at the footing level to prevent a build-up of hydrostatic
pressure against the foundation wall, and the tile must outlet to a permanent drainage system,
such as a sewer or sump pump. A check valve shall be provided to prevent the seepage of
backup water into the drainage systems from an outlet sewer system. To provide adequate
filter protection against removal of the subsoil, the tile must be surrounded by 150 mm of pea
stone (10 mm aggregate) or 19 mm clear crushed stone, and the stone must be wrapped with
filter fabric, such as Terrafix 270R, Mirafi 140NS, Amoco 4535 or equivalent.
It is recommended that basement foundation walls be damp-proofed to prevent moisture
penetration. Where walls are cast against a shoring system, approved membranes and/or
drainage boards shall be applied to the shoring to allow for drainage to the perimeter drainage
tiles and prevent moisture penetration.
3.9 FLEXIBLE PAVEMENT DESIGN
Preparation of pavement subgrades should be carried out as outlined for slab on grade
construction.
The approved subgrade may be raised to design subgrade level with approved compactable
on-site soil, providing it is placed in maximum 300 mm thick lifts and each lift is compacted to
at least 95% of the material’s MSPDD.
It is anticipated that new pavement areas will be subjected to either light or heavy traffic. Light
duty areas are defined as passenger car parking only. Heavy duty areas are main driveways
and routes where trucks would travel. Under dry subgrade and weather conditions during
construction, the following pavement designs are recommended.
160-B-0016783-1-GE-R-0001-0A
DRAFT GEOTECHNICAL ENGINEERING REPORT – BUILDING TOWER AND PARKING GARAGE, 435 R IDOUT STREET NORTH, LONDON, ONTARIO
12
Table 6 - Pavement Design
STREET
HL 3
SURFACE
ASPHALT
HL 8 BASE
ASPHALT
GRANULAR ‘A’
BASE
GRANULAR ‘B’
SUB-BASE
Light Duty 40 mm 50 mm 150 mm 300 mm
Heavy Duty 50 mm 60 mm 150 mm 400 mm
To provide drainage for the granular base and sub-base materials, including the underground
parking slabs, the subgrades shall be graded to allow favourable drainage to catch basins, and
3 metre long filtered sub-drains installed at the subgrade level at each catch basin location.
The subdrains should extend out of each face of catch basins located in parking areas, and
parallel to the edge of the pavement for catch basins on the side of roadways.
Prior to placing the pavement Granular ‘B’ sub-base layer, the road subgrade shall be proof-
rolled to compact loose zones and to identify spongy areas. Any spongy zones identified shall
be sub-excavated and replaced with drier material compacted to 98% MSPDD.
To provide uniform support for the asphalt materials, the granular base and sub-base materials
shall be compacted to 100% of their MSPDD. The asphalt must be supplied and placed in
accordance with OPSS Forms 310 and 1150.
4 STATEMENT OF LIMITATIONS
The geotechnical recommendations provided in this report are applicable only to the project
described in the text and then only if constructed substantially in accordance with the details
stated in this report. Since all details of the design may not be known at the time of report
preparation, we recommend that we be retained during the final design stage to verify that the
geotechnical recommendations have been correctly interpreted in the design. Also, if any
further clarification and/or elaboration are needed concerning the geotechnical aspects of the
project, Englobe Corp. should be contacted. We recommend that we be retained during
construction to confirm that the subsurface conditions do not deviate materially from those
encountered in the test holes and to ensure that our recommendations are properly
understood. Quality assurance testing and inspection services during construction are a
necessary part of the evaluation of the subsurface conditions.
The geotechnical recommendations provided in this report are intended for the use of the
Client or its’ agent and may not be used by a Third Party without the expressed written consent
of Englobe and the Client. They are not intended as specifications or instructions to
contractors. Any use which a contractor makes of this report, or decisions made based on it,
are the responsibility of the contractor. The contractor must also accept the responsibility for
means and methods of construction, seek additional information if required, and draw their own
conclusions as to how the subsurface conditions may affect their work. Englobe accepts no
160-B-0016783-1-GE-R-0001-0A
DRAFT GEOTECHNICAL ENGINEERING REPORT – BUILDING TOWER AND PARKING GARAGE, 435 R IDOUT STREET NORTH, LONDON, ONTARIO
13
responsibility and denies any liability whatsoever for any damages arising from improper or
unauthorized use of the report or parts thereof.
It is important to note that the geotechnical assessment involves a limited sampling of the site
gathered at specific test hole locations and the conclusions in this report are based on this
information gathered and in accordance with normally accepted practices. The subsurface
geotechnical, hydrogeological, environmental and geologic conditions between and beyond the
test holes will differ from those encountered at the test holes. Also such conditions are not
uniform and can vary over time. Should subsurface conditions be encountered which differ
materially from those indicated at the test holes, we request that we be notified in order to
assess the additional information and determine whether or not changes should be made as a
result of the conditions. Englobe will not be responsible to any party for damages incurred as a
result of failing to notify Englobe that differing site or subsurface conditions are present upon
becoming aware of such conditions.
The professional services provided for this project include only the geotechnical aspects of the
subsurface conditions at the site, unless otherwise stated specifically in the report. The
recommendations and opinions given in this report are based on our professional judgment
and are for the guidance of the Client or its’ Agent in the design of the specific project. No
other warranties or guarantees, expressed or implied, are made.
Appendix 1 Drawings
Drawing 1: Location Plan
Drawing 2: Site Plan
SITE
THAMES RIVER
10 c
m5
04
32
1
Title
Project
01 of 02
435 Ridout Street North, London, Ontario
NOTES :
1-REFERENCE : City of London online mapping tool - City Map Gallery,
accessed March 2017 (www.maps.london.ca)
2-Drawing scale may be distorted due to file conversion and/or copying.
Measurements taken from the drawing must be verified in the field.
0 100 200
SCALE 1:7500
300 m
EL.246.50
EL.246.57
EL.246.68
EL.246.58
EL.233.14
EL.236.31
EL.234.99
EL.233.01
EL.246.10
EL.233.96
EL.232.98
EL.242.42
EL.242.41
EL.243.38
EL.243.71
EL.245.15
EL.245.35
QU
EE
NS
AV
EN
UE
RID
OU
T S
TR
EE
T N
OR
TH
Title
Project
10 c
m5
04
32
1
02 02
435 Ridout Street North, London, Ontario
LEGEND :
NOTES :
1-REFERENCE : Base image from Tillmann Ruth Robinson Architects,
Drawing No. A2 - Proposed Bore Hole Locations on Proposed Site dated
January 27, 2017, Filename: RFP Geotech Investigation 20170127.pdf,
Page 6.
2-Temporary Benchmark - City of London vertical control monument V92-22.
Elevation: 246.18 m (Geodetic)
3-Drawing scale may be distorted due to file conversion and/or copying.
Measurements taken from the drawing must be verified in the field.
BOREHOLE LOCATION
GROUND SURFACE ELEVATION (m)EL.246.50
0 10 20
SCALE 1:750
30 m
Appendix 2 Boreholes
List of Abbreviations
Boreholes 01-17 to 17-17
LIST OF ABBREVIATIONS
The abbreviations commonly employed on the borehole logs, on the figures, and in the text of the report, are as follows:
Sample Types Soil Tests and Properties
AS Auger Sample CS Chunk Sample RC Rock Core SS Split Spoon TW Thinwall, Open WS Wash Sample BS Bulk Sample GS Grab Sample WC Water Content Sample TP Thinwall, Piston
SPT UC FV ø γ
wp w wl IL Ip
PP
Standard Penetration Test Unconfined Compression Field Vane Test Angle of internal friction Unit weight Plastic limit Water content Liquid limit Liquidity index Plasticity index Pocket penetrometer
Penetration Resistances Dynamic Penetration
Resistance The number of blows by a 63.5 kg (140 lb.) hammer dropped 760 mm (30 in.) required to drive a 50 mm (2 in.) diameter 60 º cone a distance 300 mm (12 in.). The cone is attached to 'A' size drill rods and casing is not used.
Standard Penetration Resistance, N (ASTM D1586)
The number of blows by a 63.5 kg (140 lb.) hammer dropped 760 mm (30 in.) required to drive a standard split spoon sampler 300 mm (12 in.)
WH sampler advanced by static weight of hammer
PH sampler advanced by hydraulic pressure
PM sampler advanced by manual pressure
Soil Description
Cohesionless Soils Compactness Condition Very Loose Loose Compact Dense Very Dense
SPT N-Value (blows per 0.30 m)
0 to 4 4 to 10 10 to 30 30 to 50 over 50
Relative Density (Dr) (%)
0 to 20 20 to 40 40 to 60 60 to 80 80 to 100
Cohesive Soils Consistency Very Soft Soft Firm Stiff Very Stiff Hard
Undrained Shear Strength (Cu)
kPa less than 12
12 to 25 25 to 50 50 to 100 100 to 200 over 200
psf less than 250
250 to 500 500 to 1000 1000 to 2000 2000 to 4000
over 4000
DTPL APL WTPL
Drier than plastic limit About plastic limit Wetter than plastic limit
Appendix 3 Figure 1
Grain Size Distribution Analyses