Agenda packet — Pinole City Council, October 18, 2022 (part 1 of 2)

22-2171 19 April 13, 2022

7.3 Foundation and Settlement
We conclude the proposed building should be supported on a stiffened shallow foundation system, such as interconnected continuous spread footings or a mat, provided the estimated foundation settlements presented in Section 6.1 are acceptable from structural standpoint.

7.3.1 Interconnected Continuous Footings
Interconnected continuous footings should be at least 18 inches wide and bottom on firm soil or bedrock. Perimeter footings should be bottomed at least 24 inches below the lowest adjacent outside grade. The perimeter footing embedment depth may be decreased by six inches where pavement or concrete flatwork is adjacent to the new building. Interior footings should be bottomed at least 18 inches below the bottom of the capillary moisture break.

For design of the interconnected continuous footings, we recommend using an initial modulus of subgrade reaction of 20 pounds per cubic inch (pci) for dead-plus-live loads (10 pci for footings located within Zone A). These values have already been scaled to account for the plan dimensions of the foundation (therefore, this is not kv1 for 1-foot-square plate) and may be increased by one-third for total load conditions. Once the structural engineer estimates the distribution of bearing stress on the bottom of the footings and the corresponding deflections, we should review the distribution and revise the modulus of subgrade reaction, if appropriate.

Footings may be designed using an allowable bearing pressure of 3,500 pounds per square foot (psf) for dead-plus-live loads; this value may be increased by one-third for total design loads, which include wind or seismic forces. The allowable bearing pressures for dead-plus-live and total loads include factors of safety of at least 2.0 and 1.5, respectively.

As discussed in Section 6.1, if the estimated static settlement for spread footings located within Zone A is not acceptable from structural standpoint, the ground beneath the spread footings within Zone A should by improved by installing DDCs that transfer building loads to less compressible alluvium (see Section 6.1.1 and 7.5).
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Lateral loads may be resisted by a combination of passive pressure on the vertical faces of the footings and friction between the bottoms of the footings and the supporting soil. To compute lateral resistance, we recommend using an uniform pressure of 1,500 psf for transient load conditions and an equivalent fluid weight of 260 pounds per cubic foot (pcf) for sustained load conditions; the upper foot of soil should be ignored unless confined by a slab or pavement.

Frictional resistance should be computed using a base friction coefficient of 0.30. The passive pressure and frictional resistance values include a factor of safety of at least 1.5 and may be used in combination without reduction.

Footing excavations should be free of standing water, debris, and disturbed materials prior to placing concrete. The bottoms and sides of the footing excavations should be moistened following excavation and maintained in a moist condition until concrete is placed. We should check footing excavations prior to placement of reinforcing steel to check for proper bearing and preparation.

7.3.2 Mat Foundation
The edge of the mat foundation should bottom at least nine inches below the lowest adjacent exterior soil subgrade; however, the edge may need to be deepened further where utility trenches, bioswales, or loose landscape soil are planned along the building’s edge. For mat design, we recommend using an initial modulus of subgrade reaction of 20 pounds per cubic inch (pci) for dead-plus-live loads (10 pci for mat located within Zone A). These values have already been scaled to account for the plan dimensions of the foundation (therefore, this is not kv1 for 1-footsquare plate) and may be increased by one-third for total load conditions. Once the structural engineer estimates the distribution of bearing stress on the bottom of the mat and the corresponding deflections, we should review the distribution and revise the modulus of subgrade reaction, if appropriate.

Considering the large area of the mat, we expect the average bearing stress under the mat to be low; however, concentrated stresses will occur at column locations and at the edges of the mat.

The mat should be designed to impose a maximum dead-plus-live-load bearing pressure of 3,500 1002 of 2177
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psf on the foundation subgrade soil. This pressure may be increased by one-third for total load conditions.

Assuming the mat is underlain by a vapor retarder, a friction factor of 0.20 may be used to compute base friction. Where the mat foundation is supported directly on soil, a friction factor of

0.30 may be used. To compute lateral resistance, we recommend using an uniform pressure of 1,500 psf for transient load conditions and an equivalent fluid weight of 260 pcf for sustained load conditions; the upper foot of soil should be ignored unless confined by a slab or pavement.

The values for friction coefficient and passive pressure include a factor of safety of 1.5 and may be used in combination without further reduction.

7.4 Concrete Slab-on-Grade Floor
The subgrade for the slab-on-grade floor (for the spread footing foundation option) or mat foundation should be prepared in accordance with our recommendations in Section 7.1.1. Where water vapor transmission through the floor slab/mat is not desirable, we recommend installing a capillary moisture break and water vapor retarder beneath the floor slab. A capillary moisture break consists of at least four inches of clean, free-draining gravel or crushed rock. The particle size of the capillary break material should meet the gradation requirements presented in Table 2.

TABLE 2
Gradation Requirements for Capillary Moisture Break
Sieve Size Percentage Passing Sieve
1 inch 90 – 100
¾ inch 30 – 100
½ inch 5 – 25
3/8 inch 0 – 6
The vapor retarder should meet the requirements for Class B vapor retarders stated in ASTM E1745. For the mat foundation option, the four-inch capillary break can be eliminated provided 1003 of 2177
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the vapor retarder meets the requirements for Class A vapor retarders. The vapor retarder should be placed in accordance with the requirements of ASTM E1643. These requirements include overlapping seams by six inches, taping seams, and sealing penetrations in the vapor retarder.

Concrete mixes with high water/cement (w/c) ratios result in excess water in the concrete, which increases the cure time and results in excessive vapor transmission through the slab or mat.

Therefore, concrete for the floor slab/mat should have a low w/c ratio - less than 0.45. Water should not be added to the concrete mix in the field. If necessary, workability should be increased by adding plasticizers. In addition, the slab should be properly cured. Before the floor covering is placed, the contractor should check that the concrete surface and the moisture emission levels (if emission testing is required) meet the manufacturer’s requirements.

7.5 Ground Improvement
We consider DDCs to be the most appropriate ground improvement method for the Zone A portion of this project. DDCs are installed under design-build contracts by specialty contractors.

The required size, spacing, length, and strength of the ground improvement elements should be determined by the design-build contractor based on the proposed structural loads and the desired level of improvement (tolerable settlement and/or desired bearing capacity).

For planning purposes, we recommend the DDCs extend to firm native alluvium or bedrock. We anticipate the DDCs will bottom 25 to 35 feet bgs. The length and spacing of the DDCs should be sufficient to limit total and differential static settlement of footing supported on improved ground to 3/4 inch and 1/2 inch across a horizontal distance of 30 feet, respectively, for design allowable bearing pressure of 3,500 psf for dead-plus-live load conditions.

We recommend the interface between the ground improvement elements and bottoms of spread footings or a mat be separated by a minimum 12-inch-thick compacted aggregate cushion, consisting of Class 2 aggregate base or crushed rock. The purpose of the aggregate cushion is to provide some degree of isolation between the two elements, which will help prevent excessive moments from being induced in the ground improvement columns during lateral loading. 1004 of 2177
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7.5.1 Load Test
We recommend the ground improvement design be verified in the field by performing at least one full-scale load test in compression and one load test in tension (if applicable). Details regarding the proposed load testing program should be included in the design-build submittal for our review prior to mobilization to the site. The load tests should be performed on nonproduction DDCs, under our observation, constructed using the same equipment, means-andmethods, area replacement ratio, and grout factor proposed for the production DDCs. The results of the load testing program should be evaluated by the design-build contractor’s engineer, as well as our engineer, to confirm the columns provide adequate factor of safety with respect to axial load failure and allowable axial deflection at the design load prior to commencing with production installation.

7.6 Permanent Below-Grade Walls
Permanent below-grade walls should be designed to resist lateral earth pressure imposed by the retained soil, as well as a surcharge pressure from nearby foundations and vehicles, where appropriate. Where permanent below-grade walls will be restrained from movement at the top or sides (e.g., retaining walls with 90-degree angle turn, such as elevator pit walls), they should be designed for at-rest conditions. We recommend restrained walls be designed using an at-rest equivalent fluid weight of 60 pcf. Retaining walls that are unrestrained at the top should be designed for active conditions using an active equivalent fluid weight of 40 pcf. To evaluate the restrained and unrestrained walls for seismic loading, we recommend using active equivalent fluid weight plus a seismic increment as shown in Table 3. 1005 of 2177
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TABLE 3
Lateral Earth Pressures for Retaining Wall Design
Wall Restraint Static Condition Seismic Condition1
Unrestrained 40 pcf 40 pcf + 16 pcf
Restrained 60 pcf 40 pcf + 41 pcf
Note 1: The 2019 CBC requires walls that retain more than six feet of backfill to be checked for seismic loading.

Where there will be vehicular traffic behind the top of a permanent wall within a horizontal distance equal to 1.5 times the height of the wall, the wall should be designed for vehicular surcharge of 50 psf at the upper 10 feet. Where existing foundations are supported above a “zone-of-influence” line extending up from a permanent wall at an inclination of 1.5:1 (horizontal: vertical), the wall should be designed for a surcharge pressure.

The design pressures recommended above are based on fully drained walls. Although belowgrade retaining walls will be above the groundwater level, water can accumulate behind the walls from other sources, such as rainfall, irrigation, and broken water lines, etc. If the earth pressures presented above are used to design the walls, they will need to incorporate a drainage system (i.e., a back drain) behind the walls. One acceptable method for back-draining a retaining wall is to place a prefabricated drainage panel against the back of the wall. The drainage panel should extend down to a perforated PVC collector pipe surrounded by at least four inches of Caltrans Class 2 permeable material or 3/4-inch drain rock wrapped in filter fabric (Mirafi 140NC or equivalent). A proprietary, prefabricated collector drain system, such as Tremdrain Total Drain or Hydroduct Coil (or equivalent), designed to work in conjunction with the drainage panel may be used in lieu of the perforated pipe surrounded by gravel described above. The pipe should be connected to a suitable discharge point; a sump and pump system may be required to drain the collector pipes for below-grade retaining walls, such as elevator pit walls.

To protect against moisture migration, below-grade retaining walls should be waterproofed and water stops should be placed at all construction joints. If backfill is required behind retaining 1006 of 2177
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walls, the walls should be braced, or hand compaction equipment used, to prevent unacceptable surcharges on walls (as determined by the structural engineer).

7.7 Temporary Cut Slopes and Excavation Shoring
Excavations that will be entered by workers should be shored or sloped in accordance with the Occupational Safety and Health Administration (OSHA) standards (29 CFR Part 1926). The contractor should be responsible for the construction and safety of temporary slopes. The shoring designer should be responsible for the shoring design.

Where space permits, the sides of the temporary excavation can be sloped. We recommend temporary slopes not exceed an inclination of 1:1 (horizontal to vertical) in clayey soil (OSHA Type B Soil). Where space does not permit sloping of the excavation perimeter, a shoring system will be required to support the sides of the proposed excavation. We judge that a cantilevered soldier pile and lagging shoring system is appropriate for support of excavations that are less than 12 feet deep.

A structural/civil engineer knowledgeable in this type of construction should be retained to design the shoring. The shoring designer should design the shoring system for lateral deformation of less than one inch at any location on the shoring (1/2 inch if neighboring structures are within a horizontal distance equal to two times the height of the shoring). We should review the final shoring plans and calculations to check that they are consistent with the recommendations presented in this report.

7.7.1 Cantilevered Soldier-Pile-and-Lagging Shoring System A cantilevered soldier pile and lagging system should be designed using an active equivalent fluid weight of 40 pcf for level backfill conditions. Where traffic loads are expected within 10 feet of the shoring walls, an additional design load of 50 psf should be applied to the upper 10 feet of the wall. Shoring should be designed for surcharge loads where there will be construction equipment and/or stockpiled soil within a horizontal distance of 1.5 times the excavation height from the edge of excavation. We can provide recommendations for surcharge pressures once surcharge loads are known.
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Passive resistance at the toe of the soldier piles should be computed using an equivalent fluid weight of 260 pcf, with a maximum passive earth pressure of 2,500 psf. The upper foot of soil should be ignored when computing passive resistance. Passive pressure can be assumed to act over an area of three soldier pile widths assuming the toe of the soldier pile is filled with structural concrete. If lean concrete is placed in the soldier pile shaft, the passive pressure can be assumed to act over two pile diameters. These passive pressure values include a factor of safety of at least 1.5.

Soldier piles should be placed in pre-drilled holes backfilled with concrete or installed in soilmix columns. The subsurface soils include lenses of clayey sands. The shoring contractor should be prepared to use casing or drilling slurry to reduce caving of holes, where necessary. Installing soldier piles using a vibratory method is not recommended within 25 feet of existing structures.

7.8 Pavement and Paver Design
Design recommendations for asphalt concrete and Portland cement concrete pavements, and concrete pavers are presented in the following sections.

7.8.1 Flexible (Asphalt Concrete) Pavement Design
The State of California flexible pavement design method was used to develop the recommended asphalt concrete pavement sections. The final soil subgrade in pavement areas will likely consist of sandy clay or clayey sand. Based on our experience with similarly soils, we recommend a preliminary resistance value (R-value) of 15 be used for asphalt concrete pavement design.

Recommended pavement sections for traffic indices (TIs) ranging from 4.5 to 6.5 are presented in Table 4. The Civil Engineer for the project should check that the TIs presented in this report are appropriate for the intended use. We can provide additional pavement sections for different TIs upon request.
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TABLE 4
Asphalt Concrete Pavement Sections
R-Value of 15 for Subgrade Soil
Traffic
Index
Asphaltic Concrete
(inches)
Class 2 Aggregate Base
(inches)

4.5 2.5 8.0

5.0 3.0 8.0

5.5 3.0 10.0

6.0 3.5 10.5

6.5 4.0 11.5
The upper eight inches of the subgrade should be moisture-conditioned and compacted in accordance with requirements presented in Section 7.1. The subgrade should be proof-rolled under the direction of our field engineer to confirm it is non-yielding prior to placement of aggregate base. The aggregate base should be moisture conditioned to near optimum and compacted to at least 95 percent relative compaction. The aggregate base should also be proofrolled to confirm it is non-yielding prior to paving.

If pavements are adjacent to irrigated landscaped areas, curbs adjacent to those areas should extend through the aggregate base and at least three inches into the underlying soil to reduce the potential for irrigation water to infiltrate into the pavement section. If drip irrigation is used in the landscaping adjacent to the pavement, however, the deepened curb is not required.

7.8.2 Rigid (Portland-Cement Concrete) Pavement Design
The Portland-cement concrete (PCC) pavement section design is based on a maximum singleaxle load of 20,000 pounds and a maximum tandem axle of 32,000 pounds (i.e., several garbage trucks per week). The recommended rigid pavement section for these axle loads is 6.5 inches of Portland-cement concrete over six inches of Class 2 aggregate base. For areas that will receive fire truck traffic, the pavement section should consist of seven inches of Portland-cement concrete over six inches of Class 2 aggregate base. For areas that will experience only passenger 1009 of 2177
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vehicle traffic, the recommended pavement section is five inches of PCC over six inches of Class 2 aggregate base.

The modulus of rupture and unconfined compressive strength of the concrete should be at least 500 and 3,200 psi at 28 days, respectively. Contraction joints should be placed at a 15-foot spacing. Where the outer edge of a concrete pavement meets asphalt pavement, the concrete slab should be thickened by 50 percent at a taper not to exceed a slope of 1 in 10. For concrete pavements subject to truck loading, we recommend the concrete slab be reinforced with a minimum of No. 4 bars at 16 inches on center in both directions.

The soil subgrade beneath Portland cement concrete pavements should be prepared and compacted in accordance with the recommendations presented in Section 7.1. In addition, the subgrade should be a firm and non-yielding surface. The subgrade should be proof-rolled under the direction of our field engineer to confirm it is non-yielding prior to placing the aggregate base. The Class 2 aggregate base should be moisture-conditioned to near optimum moisture content and compacted to at least 95 percent relative compaction.

7.8.3 Non-Permeable Concrete Pavers
Where non-permeable concrete pavers will be subject to vehicular traffic, we recommend they consist of fully dentated, interlocking shapes and be at least 80 millimeters (3.15 inches) thick.

The pavers should be placed on a 1- to 2-inch-thick sand leveling course underlain by Class 2 aggregate base. The thickness of the Class 2 aggregate base beneath non-permeable pavers subject to vehicular traffic should be consistent with the sections presented for asphalt pavement in Section 7.8.1 for the applicable TI. The subgrade and aggregate base should be compacted in accordance with the recommendations for asphalt pavement in Section 7.8.1.

7.8.4 Permeable Concrete Pavers
We recommend permeable interlocking concrete pavements (ICP) be designed in accordance with the guidelines presented by the Interlocking Concrete Pavement Institute (ICPI 2005).

These guidelines include specific recommendations for permeable aggregate subbase, base, and bedding courses to be placed beneath ICP pavements. We recommend permeable pavements for 1010 of 2177
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both vehicular and pedestrian traffic be designed for no exfiltration and partial exfiltration of water into the subgrade soil, respectively. This requires installing a subdrain system at the base of the pervious aggregate materials, which are underlain by an impermeable liner. ICPI’s generalized paver section for no exfiltration and partial exfiltration are presented on Figures 6 and 7, respectively.

The soil subgrade beneath ICP pavements should be prepared and compacted in accordance with the recommendations presented in Sections 7.1. In addition, the subgrade should be a firm and non-yielding surface. The subgrade should be proof-rolled under the observation of our field engineer to confirm it is non-yielding prior to placing the impermeable membrane and aggregate base materials. The soil subgrade at the bottom of the permeable section should slope down toward the drainpipe trench at a gradient of at least two percent. The perforated pipe should slope down to a suitable outlet at a minimum gradient of one percent. The pipe should be placed with the perforations down on a minimum of two inches of permeable subbase.

ICPI’s guidelines call for 1-1/2 to 2 inches of bedding material consisting of ASTM No. 8 crushed aggregate directly below the pavers. This material is also recommended for fill material between the pavers. As shown in Table 5 below, this material consists of fine gravel with 10 to 30 percent sand.

TABLE 5
Gradation Requirements for ASTM No. 8 Crushed Aggregate Sieve Size Percentage Passing Sieve
1/2 inch 100
3/8 inch 85 – 100
No. 4 10 – 30
No. 8 0 – 10
No. 16 0 – 5
The ASTM No. 8 bedding should be underlain by a permeable base course of ASTM No. 57 crushed aggregate. As shown in Table 6, ASTM No. 57 aggregate consists of crushed, open1011 of 2177 22-2171 30 April 13, 2022
graded gravel with a gradation between that of the 3/4-inch drain rock and the ASTM No. 8 aggregate.

TABLE 6
Gradation Requirements for ASTM No. 57 Crushed Aggregate Sieve Size Percentage Passing Sieve
1-1/2 inch 100
1 inch 95 – 100
1/2 inch 25 – 60
No. 4 0 – 10
No. 8 0 – 5
The ASTM No. 57 permeable base course should be underlain by a permeable subbase course of ASTM No. 2 crushed aggregate. The gradation requirements for ASTM No. 2 crushed aggregate subbase are presented in Table 7.

TABLE 7
Gradation Requirements for ASTM No. 2 Crushed Aggregate Sieve Size Percentage Passing Sieve
3 inch 100
2-1/2 inch 90-100
2 inch 35-70
1-1/2 inch 0-15
3/4 inch 0 -5
The No. 2 crushed aggregate subbase course should be placed in lifts not exceeding 6 inches in loose thickness and compacted using a smooth-drum roller that weighs a minimum of 10 tons, operated in static (non-vibratory) mode. The subsequent course of No. 57 crushed aggregate may be placed in one lift and should be compacted with a smooth-drum roller in vibratory mode with sufficient passes to create an unyielding surface. Placement and compaction of the permeable 1012 of 2177
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aggregate base and subbase should be performed under the observation of our field engineer.

Following compaction of the No. 57 aggregate, the No. 8 bedding, not exceeding 2 inches in loose thickness, should be placed and screeded to a level, undisturbed surface immediately prior to paver installation.

The required thicknesses of the permeable aggregate base and subbase courses depends on the infiltration and water storage design requirements, as well as the traffic loading demand. Our recommendations for the minimum permeable ICP pavement sections subject to vehicular traffic (including fire and garbage trucks) are presented in Table 8. Where permeable pavement will be subject to fire trucks, we recommend a layer of triaxial geogrid (i.e., Tensar TriAx TX-140 Geogrid or equivalent) be placed atop the soil subgrade prior to placing the paver aggregates.

Also included in Table 8 is a recommended section for permeable ICPs subject to pedestrian traffic only.

TABLE 8
Recommended Pavement Sections for
Permeable Interlocking Concrete Pavers
Pavement
Type
ASTM No. 8
Crushed Bedding
Aggregate
(inches)
ASTM No. 57
Crushed Base
(inches)
ASTM No. 2
Crushed
Subbase
(inches)
Pedestrian 1.5-2.0 4.0 6.0
Vehicular 1.5-2.0 4.0 10.0
The above recommended ICP pavement sections are based on the ICPI technical guidelines (ICPI 2005). From a geotechnical standpoint, it is acceptable to design the pedestrian ICP section to exclude the No. 2 subbase course, in which case the No. 57 base course should be increased to 10 inches. If this approach is used, the perforated pipe should include a filter fabric sleeve to prevent the finer aggregate from entering the perforations. 1013 of 2177
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7.9 Seismic Design
The latitude and longitude of the site are 37.9907° and -122.3049°, respectively. For design in accordance with 2019 CBC, we recommend the following:
• Site Class D – stiff soil
• SS = 2.243g, S1 = 0.852g
The 2019 CBC is based on the guidelines contained within ASCE 7-16 which stipulates that where S1 is greater than 0.2 times gravity (g) for Site Class D, a ground motion hazard analysis is needed unless the seismic response coefficient (Cs) value will be calculated as outlined in Section 11.4.8, Exception 2. Assuming the Cs value will be calculated as outlined in Section

11.4.8, Exception 2, we recommend the following seismic design parameters:
• Fa = 1.00, Fv = 1.7
• SMS = 2.243g, SM1 = 1.448g
• SDS = 1.495g, SD1 = 0.966g
• Seismic Design Category E for Risk Factors I, II, and III

8.0 ADDITIONAL GEOTECHNICAL SERVICES
Prior to construction, Rockridge Geotechnical should review the project plans and specifications to verify that they conform to the intent of our recommendations. During construction, our field engineer should provide on-site observation and testing during site preparation, placement and compaction of fill, and installation of building foundations. These observations will allow us to compare actual with anticipated subsurface conditions and to verify that the contractor's work conforms to the geotechnical aspects of the plans and specifications.

9.0 LIMITATIONS
This geotechnical investigation has been conducted in accordance with the standard of care commonly used as state-of-practice in the profession. No other warranties are either expressed or implied. The recommendations made in this report are based on the assumption that the subsurface conditions do not deviate appreciably from those disclosed in our CPTs and borings. 1014 of 2177
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If any variations or undesirable conditions are encountered during construction, we should be notified so that additional recommendations can be made. The foundation recommendations presented in this report are developed exclusively for the proposed development described in this report and are not valid for other locations and construction in the project vicinity. 1015 of 2177
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REFERENCES
2019 California Building Code.

Boulanger, R.W and Idriss, I.M. (2014). “CPT and SPT Based Liquefaction Triggering Procedures”, Center for Geotechnical Modeling, Department of Civil and Environmental Engineering, University of California, Davis, Report No. UCD/CGM-14/01, April.

Cao, T., Bryant, W. A., Rowshandel, B., Branum D. and Wills, C. J. (2003). “The Revised 2002 California Probabilistic Seismic Hazard Maps”.

California Geological Survey (2003). Earthquake Zones of Required Investigation, Richmond Quadrangle, Official Map, February 14, 2003.

Conestoga-Rovers & Associates (2012). First Semi-Annual 2012 Groundwater Monitoring Report, Former Texaco Service Station 21-1212, 1599 Tara Hills Drive, Pinole, California. April

4. Environmental Resolutions, Inc. (2000). Quarterly Groundwater Monitoring Report, Third Quarter 2000, Former Exxon Service Station 7-6141, 2401 Appian Way, Pinole, California.

October 31.

Field, E.H., Biasi, G.P., Bird, P., Dawson, T.E., Felzer, K.R., Jackson, D.D., Johnson, K.M., Jordan, T.H., Madden, C., Michael, A.J., Milner, K.R., Page, M.T., Parsons, T., Powers, P.M., Shaw, B.E., Thatcher, W.R., Weldon, R.J., II, and Zeng, Y., (2013). Uniform California earthquake rupture forecast, version 3 (UCERF3)—The time-independent model: U.S.

Geological Survey Open-File Report 2013–1165, 97 p.

Graymer, R.W. (2000), “Geologic Map and Map Database of the Oakland Metropolitan Area, Alameda, Contra Costa and San Francisco Bay Counties, California”, U.S. Geological Survey Miscellaneous Field Studies MF-2342.

Graymer, R.W., Moring, B.C., Saucedo, G.J, Wentworth, C.M., Brabb, E.E., and Knudsen, K.L. (2006). Geologic Map of the San Francisco Bay Region, prepared in cooperation with U.S.

Geological Survey and California Geological Survey, March 6.

Ishihara, K. and Yoshimine, M., (1992), Evaluation of Settlements in Sand Deposits Following Liquefaction During Earthquakes, Soils and Foundations, Volume 23, No. 1, pp 173-188.

Petersen, M.D., Moschetti, M.P., Powers, P.M., Mueller, C.S., Haller, K.M., Frankel, A.D., Zeng, Y., Rezaeian, S., Harmsen, S.C., Boyd, O.S., Field, E.H., Chen, R., Rukstales, K.S., Luco, N., Wheeler, R.L., Williams, R.A., and Olsen, A.H., (2014). Documentation for the 2014 update 1016 of 2177
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of the United States national seismic hazard maps: U.S. Geological Survey Open-File Report 2014–1091, 243 p.

Robertson, P.K. (2009), “Interpretation of Cone Penetration Tests - A Unified Approach”, Canadian Geotechnical Journal, Vol. 46, No. 11, pp 1337-1355.

Thompson, E.M., Wald, D.J, Worden, B., Field, E.H., Luco, N., Petersen, M.D., Powers, P.M., Badie, R. (2016) Shakemap earthquake scenario: Building Seismic Safety Council 2014 Event Set (BSSC2014). U.S. Geological Survey. DOI: 10.5066/F7V122XD Toppozada, T.R. and Borchardt G. (1998). “Re-evaluation of the 1936 “Hayward Fault” and the 1838 San Andreas Fault Earthquakes.” Bulletin of Seismological Society of America, 88(1), 140-159.

Zhang, G., Robertson. P.K., Brachman, R., (2002), “Estimating Liquefaction Induced Ground Settlements from the CPT”, Canadian Geotechnical Journal, 39: pp 1168-1180. 1017 of 2177

FIGURES
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Date Project No. Figure 1

ROCKRIDGEGEOTECHNICAL
0 3,800 Feet
Approximate scale
1,900
Base map: Google Maps, 2021
SITE

SITE LOCATION MAP
03/31/22 22-2171
1500 FITZGERALD DRIVE
Pinole, California
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0Approximate scale80 Feet 04/13/22 22-2171 2 Pinole, California SITE PLAN Date Project No. Figure ROCKRIDGE GEOTECHNICAL 1500 FITZGERALD DRIVE EXPLANATION Approximate location of cone penetration test by Rockridge Geotechnical, Inc., February 28, 2022 Approximate location of boring by Rockridge Geotechnical, Inc., March 15, 2022 Project limits B-1 CPT-1Reference: Base map from a drawing titled "Site Plan", by Trachtenberg Architects, dated April 7, 2021. B-1 B-2 CPT-1 CPT-2 CPT-3 CPT-7 CPT-6 CPT-5 CPT-4FITZGERALD DRIVE FOUNDATION DESIGN ZONE A 1020 of 2177

REGIONAL GEOLOGIC MAP

ROCKRIDGE

GEOTECHNICAL
Approximate scale
2,000
Date Project No. Figure 3
0 4,000 Feet
04/01/22 22-2171
1500 FITZGERALD DRIVE
Pinole, California
Geologic contact:
dashed where approximate and dotted
where concealed, queried where uncertain
SITE

EXPLANATION
Qpa
Base map: Google Earth with U.S. Geological Survey (USGS), Contra Costa County, 2021.

Tpmv
Tms
Qpa
Qpa
Qpa
af
Qhym
af
Tms
Tpms
Tms
Tpms
Qha
af
Qpa
Qhym
Tms
Tms
Artificial Fill
Mud deposits (late Holocene)
Alluvium (Holocene)
Alluvium (Pleistocene)
Sedimentary rocks (Pliocene and early Miocene)
Sedimentary rocks (Miocene)
Volcanic rocks (Pliocene and early Miocene)
af
Qhym
Qha
Qpa
Tpms
Tpmv
Tms
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Date Project No. Figure
Base Map: U.S. Geological Survey (USGS), National Seismic Hazards Maps - Fault Sources, 2014. 10 Miles
Approximate scale
0 5

ROCKRIDGE

GEOTECHNICAL

REGIONAL FAULT MAP
SITE

EXPLANATION
Strike slip
Thrust (Reverse)
03/31/22 22-2171 4
1500 FITZGERALD DRIVE
Pinole, California
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Date Project No. Figure

LIQUEFACTION SUSCEPTIBILITY

VERY LOW
LOW

MODERATE
HIGH

VERY HIGH
Contact, dashed where location uncertainty
is greater than about +- 100 m.

Lines
5 0 3 Miles
Approximate scale

1.5 SITE

LIQUEFACTION SUSCEPTIBILITY MAP
Reference:

Maps of Quaternary Deposits and Liquefaction Susceptibility in the Central San Francisco Bay Region, California, by USGS, 2006

ROCKRIDGE
GEOTECHNICAL 04/11/22 22-2171
1500 FITZGERALD DRIVE
Pinole, California
1023 of 2177
Date Project No. Figure 6 ROCKRIDGE GEOTECHNICAL Reference: "Permeable Interlocking Concrete Pavements", Third Edition, prepared by Interlocking Concrete Pavement Institute, dated 2005. 4 in (100 mm) thick No. 57
stone open-graded base GENERALIZED ICPI PERMEABLE PAVER DETAIL FOR NO EXFILTRATION No. 2 stone subbase - thickness varies with design Impermeable liner on bottom and sides of open-graded base Typ. No. 8 aggregate in openings
Curb/edge restraint with cut-outs for
overflow drainage or optional overflow pipe
Concrete pavers min. 3 18 in. (80 mm) thick
Bedding course 1 12 to 2 in. (40 to 50 mm) thick
(typ. No. 8 aggregate)
Perforated pipes spaced and
sloped to drain all stored water
Outfall pipe(s) sloped to storm sewer or stream Soil subgrade sloped to drain 04/11/22 22-2171 Pinole, California 1500 FITZGERALD DRIVE 1024 of 2177
Date Project No. Figure 7 ROCKRIDGE GEOTECHNICAL Reference: "Permeable Interlocking Concrete Pavements", Third Edition, prepared by Interlocking Concrete Pavement Institute, dated 2005. 4 IN (100 MM) THICK NO. 57 STONE OPEN-GRADED BASE TYP. NO. 8, 89, OR 9 AGGREGATE IN OPENINGS CURB/EDGE RESTRAINT WITH CUT-OUTS FOR OVERFLOW DRAINAGE (CURB SHOWN) CONCRETE PAVERS MIN. 3 18 IN. (80 MM) THICK FOR VEHICULAR TRAFFIC (ASPECT RATIO< 3) BEDDING COURSE 1 12 TO 2 IN. (40 TO 50 MM) THICK (TYP. NO. 8 AGGREGATE) PERFORATED PIPES SPACED AND SLOPED TO DRAIN ALL STORED WATER SOIL SUBGRADE SLOPED TO DRAIN MIN. 6 IN. (150 MM) THICK NO. 2 STONE SUBBASE GEOTEXTILE ON TOP AND SIDES OF SUBBASE UNDER/BEYOND CURB GEOTEXTILE ON SUBGRADE NON-PERFORATED OUTFALL PIPE(S) SLOPED TO STORM SEWER OR STREAM NOTES: 1. 2 38 IN. (60 MM) THICK PAVERS MAY BE USED IN RESIDENTIAL APPLICATIONS. 2. NO. 2 STONE SUBBASE THICKNESS VARIES WITH DESIGN. CONSULT ICPI PERMEABLE INTERLOCKING CONCRETE PAVEMENT MANUAL.. 3. PERFORATED PIPES MAY BE RAISED FOR WATER STORAGE FROM LARGE RAIN EVENTS WITH OUTLET(S) AT LINER BOTTOM TO DRAIN SMALL RAIN EVENTS. GENERALIZED ICPI PERMEABLE PAVER DETAIL FOR PARTIAL EXFILTRATION 04/11/22 22-2171 Pinole, California 1500 FITZGERALD DRIVE 1025 of 2177

APPENDIX A
Cone Penetration Test Results and Logs of Borings
1026 of 2177
A-1
CPT-1
Total depth: 29.7 ft, Date: February 28, 2022Depth to Groundwater: 19.7 feet (based on groundwater level in Boring B-1)Cone Operator: Middle Earth Geo Testing, Inc.

Date Project No. Figure
SBT legend

1. Sensitive fine grained2. Organic material3. Clay to silty clay

4. Clayey silt to silty clay5. Silty sand to sandy silt6. Clean sand to silty sand