THURBER ENGINEERING LTD.G E O T E C H N I C A L � E N V I R O N M E N TA L � M AT E R I A L S

Suite 200, 1445 West Georgia Street, VANCOUVER, B.C., Canada V6G 2T3 T.604-684-4384 F.604-684-5124 www.thurber.caVANCOUVER � VICTORIA � KAMLOOPS � SQUAMISH � EDMONTON � CALGARY � FORT McMURRAY � TORONTO

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October 7, 2009 File: 17-123-559 Associated Engineering Ltd Suite 300 - 4940 Canada Way Burnaby, BC V5G 4M5 Attention: Mr. Mark Porter

1100 EAST KENT AVENUE SOUTH RECYCLING CENTRE GEOTECHNICAL INVESTIGATION

Dear Mark: As requested, Thurber Engineering Ltd. (TEL) has carried out a geotechnical investigation at the City of Vancouver’s (the City) recycling facility located at 1100 East Kent Avenue South. This report summarizes the results of our investigation and provides geotechnical recommendations for the design of foundations and retaining structures at the site. Use of this report is subject to the enclosed Statement of General Conditions. 1. BACKGROUND

The existing recycling facility at the site comprises an asphalt surface with at-grade sorting areas separated by Lock-Block walls and is located approximately 25 m from the banks of the Fraser River. At this time, we understand that the proposed concept to construct a permanent structure has been postponed indefinitely, and work at the site will be limited to erection of a chain link fence around the perimeter of the property with no site grading works. Recommendations for footing design for the proposed fence are provided in the report below along with our preliminary recommendations pertaining to the original proposed concept.

2. PROGRAM OF WORK

One seismic cone penetration test (SCPT) was carried out near the south end of the site, as shown on the attached Dwg 17-123-559-1. Please note that the building configuration indicated on the drawing is one of two options that had been contemplated in the original project scope, and does not reflect the currently proposed site configuration. Testing was conducted by Dynamic Drilling Inc. on February 19, 2008. The SCPT was conducted to a depth of about 11.5 m below ground surface, where the cone met refusal.

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Client: Associated Engineering Ltd Date: October 7, 2009 File No. 17-123-559 E file: b_aww_let_1100 e kent geotech report Page 2 of 6

The SCPT provides measurements of tip resistance and sleeve friction on the cone, as well as the surrounding pore water pressure in the soil. Shear wave velocities were also obtained at regular intervals. The SCPT profile is attached for reference. Historical information is also available on the site including several test pits excavated prior to construction of the existing facility. TPs 01-1 to 01-5 were excavated in September 2001 to depths between about 2.5 and 3.5 m. The locations are shown on Dwg 17-123-559-1 and the logs are attached for reference.

3. RESULTS OF SITE INVESTIGATION

3.1 General The results of our recent and historical site investigations are described below. Note that the detailed logs should be used in preference to the generalized descriptions presented below.

3.2 Seismic Cone Penetration Test The soil profile at the SCPT test location consists of variable fill from ground surface to about 3.3 m depth, underlain by fine grained soil (clay and/or silt) to about 7.5 m, which is underlain by a thick layer of sand extending to about 11 m. Below the sand, there is a thin silt layer extending to about 11.5 m. The SCPT was terminated after meeting refusal in very dense soil at about 11.5 m below ground surface. Assuming that the pore water pressure in the thick sand unit is hydrostatic, we estimate that the water table was at about 4 m depth below ground surface at the time of testing. However, due to the site’s proximity to the Fraser River delta, the water table likely undergoes tidal fluctuations on a daily basis. Shear wave velocities, measured at approximately 1 m intervals between 2.2 m and the bottom of the test hole, ranged between about 110 and 265 m/s and generally increased with depth. 3.3 Historical Test Pits

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Client: Associated Engineering Ltd Date: October 7, 2009 File No. 17-123-559 E file: b_aww_let_1100 e kent geotech report Page 3 of 6

Historical test pits provide information about the fill materials present near ground surface at the site. In general, fill materials on site are highly variable. Test pits extended to depths of up to 3.4 m and exposed materials including crushed asphalt, woodwaste, silt and sand mixtures and granular, sand and gravel fill. These materials are typically compact to dense or firm to stiff in consistency. Seepage was observed in TPs 01-3 and 01-5 below about 3.0 and 2.8 m depth, respectively. The remainder of the test pits were dry to the bottom of the excavation.

4. ENGINEERING ASSESSMENT AND RECOMMENDATIONS

4.1 General

Recommendations are provided in section 4.2 below for the design of footings for the currently contemplated chain link fence that will surround the perimeter of the property. Preliminary recommendations pertaining to the original project scope are also provided in section 4.3. 4.2 Perimeter Fence Footings We understand that the proposed chain link fence will be supported on shallow concrete pad footings. We recommend that footings be designed for a maximum allowable bearing pressure of 75 kPa. Footings should have a minimum dimension of 600 mm and a minimum depth of cover of 450 mm below ground surface for frost protection. Any woodwaste or other soft and/or deleterious materials encountered at the bearing surface of any footing should be subexcavated and replaced with compacted granular fill. TEL should inspect the exposed subgrade prior to pouring of the footings.

4.3 Future Permanent Engineered Structure 4.3.1 General The proposed structure was to include the construction of covered sorting areas using a permanent, prefabricated engineered structure. The structure was to be built on a raft foundation, approximately within the footprint of the existing sorting and storage areas, without raising site grades.

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4.3.2 Seismic Considerations Based on data obtained from the SCPT, we consider that granular soil found at depth will be susceptible to liquefaction during a seismic event. We expect that liquefaction will primarily manifest itself as vertical ground settlement and lateral movement of the ground towards the free face found at the north bank of the Fraser River. The magnitude of lateral movement will be controlled by the strength and duration of shaking during a seismic event, with movements on the order of several metres to be expected for a 1:2475 year event. To achieve seismic performance requirements outlined in the Building Code, a structurally connected raft slab foundation is recommended. This will allow building construction to proceed without ground improvement. However, the entire raft slab and building would be expected to deform both horizontally and vertically during a seismic event. As the underlying soils are susceptible to liquefaction, the site is considered a Class F, in accordance with the BC Building Code, and requires a site-specific response analysis. Our site-specific response analysis was carried out using the programs EERA (Equivalent-linear Earthquake Response Analysis) and NERA (Non-linear Earthquake Response Analysis) to determine the spectral acceleration (Sa) at the site as a function of the design building period. Preliminary results of our analyses were by transmitted to Associated Engineering via e-mail on March 10, 2009 but are not included in this report given the potential uncertainty in future structure type.

4.3.3 Foundation and Settlement Considerations Compressible soil is present underlying the site. Provided site grades are not raised, we do not consider that post construction foundation settlement will be a significant issue. Potential small foundation settlements will be mitigated by the raft type foundation, which will spread the building load over the entire building footprint and help to reduce long term total and differential settlement.

4.3.4 Coefficient of Horizontal Pressure for Stockpiled Paper The proposed prefabricated engineered structure included several containment areas where recyclable paper would be temporarily stored. The walls of these containment areas would be required to withstand the horizontal pressure exerted by the stockpiled paper. At your request, we have researched values to be used as a coefficient of horizontal pressure

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Client: Associated Engineering Ltd Date: October 7, 2009 File No. 17-123-559 E file: b_aww_let_1100 e kent geotech report Page 5 of 6

(ko) for paper, analogous to the coefficient of horizontal earth pressure used for soil. According to Pelkey (1997), values of ko were determined for several samples, generally comprising varying compositions of refuse, through consolidation and direct shear tests. Values for a coefficient of active horizontal pressure (ka) were also reported and shown to develop in paper samples, but testing indicated that these values tended to creep back to the ko value with time. Therefore, ko conditions are recommended for design. A summary of friction angles obtained through direct shear testing are presented in Table 1 below, along with ko values. Table 1. Values of Φ and ko for Various Paper Samples

Paper Condition Φ (o) ko Dry, Stacked 21 0.64

Dry, Shredded 25 0.58 Wet, Shredded 40 0.36

Given the unknown and likely variable nature of the paper waste to be stored, we consider the upper bound value of ko to be appropriate for design. 4.3.5 Subgrade Modulus An estimate of the Modulus of Subgrade Reaction (ks) is required for the design of raft foundations. Preliminary estimates were transmitted to Associated Engineering via e-mail on March 10, 2009 but are not included with this report given the potential uncertainty in raft slab geometry.

5. REFERENCES

Pelkey, S.G. (1997). Geotechnical Properties of Municipal Solid Waste. Department of Civil Engineering, MASc Thesis, University of New Brunswick, Fredericton, Canada, September 1997.

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Maximum Depth = 11.55 meters Depth Increment = 0.05 meters

1 sensitive fine grained 2 organic material 3 clay

4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt

7 silty sand to sandy silt 8 sand to silty sand 9 sand

10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*)

THURBER Operator: Dynamic Drilling Inc. Sounding: CPT09 - 1 Cone Used: HT1094 10 Ton

Date: February 19, 2009 Site: Kent Recycling Facility Thurber Project Number: 17 - 123 - 559

0

2

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0 50 100 150 200 250

TIP RESISTANCEqt (Bar)

Dep

th (m

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0 1 2

SLEEVE FRICTION (Bar)

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0 1 2 3 4 5 6

FRICTION RATIO (%)

-10 0 10 20

U2 Pp (Meter)

0 12Robertson et al, 1986Soil Behavior Type*

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Maximum Depth = 11.55 meters Depth Increment = 0.05 meters

1 sensitive fine grained 2 organic material 3 clay

4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt

7 silty sand to sandy silt 8 sand to silty sand 9 sand

10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*)

THURBER Operator: Dynamic Drilling Inc. Sounding: CPT09 - 1 Cone Used: HT1094 10 Ton

Date: February 19, 2009 Site: Kent Recycling Facility Thurber Project Number: 17 - 123 - 559

0

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TIP RESISTANCEqt (Bar)

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SPT N(60) (Blow/ft)

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SPT N1(60) (Blow/ft)

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Su (kPa) Nkt = 13

0 12Robertson et al, 1986Soil Behavior Type*

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CONE TIP GEOPHONE INTERVALDEPTH DEPTH VELOCITY

(m) (m) (m/sec)1.70 1.45

1162.70 2.45

1133.70 3.45

1404.70 4.45

1275.70 5.45

1496.70 6.45

1727.70 7.45

2238.70 8.45

21510.70 10.45

26511.55 11.30

SHEAR WAVE VELOCITY DATA Client: Thurber Engineering Ltd. Test: CPT09 - 1 Site: Kent Recycling Facility Vancouver, B.C.

Date: February 19, 2009 Cone ID: HT1094 10 Ton Source offset: 1.0 m Source: Beam

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SHEAR WAVE VELOCITY - Vs (m/sec)

DEP

TH (m

eter

)SHEAR WAVE VELOCITY PROFILE

Client: Thurber Engineering Ltd. Test: CPT09 - 1 Site: Kent Recycling Facility Vancouver, B.C.

Date: February 19, 2009 Cone ID: HT1094 10 Ton Source offset: 1.0 m Source: Beam

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