UPDATE GEOTECHNICAL REPORT FOR 301 CAZADOR LANE, …

UPDATE GEOTECHNICAL REPORT FOR

301 CAZADOR LANE, FOUR 2-STORY APARTMENTS

SAN CLEMENTE, ORANGE COUNTY, CALIFORNIA

FOR

MR. CHRIS PIERCE

C/O MR. RICK MOSER

21296 MONTERRA

LAKE FOREST, CALIFORNIA 92630

W.O. 6442-A-SC OCTOBER 10, 2012

Geotechnical C Geologic C Coastal C Environmental

26590 Madison Avenue C Murrieta, California 92562 C (951) 677-9651 C FAX (951) 677-9301 C www.geosoilsinc.com

October 10, 2012W.O. 6442-A-SC

Mr. Chris Pierce

c/o Mr. Rick Moser

21296 MonterraLake Forest, California 92630

Subject: Update Geotechnical Report for 301 Cazador Lane, Four 2-Story Apartments,San Clemente, Orange County, California

Dear Mr. Moser:

In accordance with your request and authorization, GeoSoils, Inc. (GSI) has performed asite evaluation and review of the referenced project plans (Jones, Cahl &Associates [2012]; and R. Moser [2012]; see Appendix A). The 2010 California BuildingCode ([2010 CBC], California Building Standards Commission [CBSC], 2010), and relatedcodes are the guidance documents for the project. The purpose of our evaluation andreview was to provide an update to the referenced report and response by GSI (2007 and2008, respectively) for the subject site. The update was considered necessary due to theduration of time between original project development and changing standards of practiceand code. The scope of our services included a site reconnaissance, engineeringanalyses, and preparation of this update report. It should be noted that owing to currentCode, as well as changes in the standards of practice, some revision to the existing designwill likely be required.

SITE LOCATION/PROPOSED DEVELOPMENT

The subject site is located southeast of the intersection of South Ola Vista and CazadorLane in San Clemente, Orange County, California (see Figure 1, Site Location Map). Thesubject property site is irregular in plan, roughly 164 feet on the north side and 130 feet onthe south side in length. The approximate width of the property on the east side is 70 feetand 73 feet on the west side. The approximate building footprint is 120 feet in length and50 feet in width. The eastern half of the site overlies an old canyon, which was likely filledin for the construction of South Ola Vista. The center of the canyon likely follow the currentstorm drain easement and still exists to the north and south of the site.

SITE LOCATION MAPPierce Development

301 Cazador Lane, San Clemente

Reproduced with permission granted by Thomas Bros.Maps. This map is copyrighted by Thomas Bros. Maps.It is unlawful to copy or reproduce all or any part thereof,whether for personal use or resale, without permission.All rights reserved.

Figure 1

W.O. 6442-A-SC DATE 10/12 SCALE: 1” = 2,000

Base Map: TOPO!® ©2007 National Geographic, U.S.G.S. Dana Point and San Clemente Quadrangles, California,Orange Co., 7.5 Minute, dated 1975.

Base Map: The Thomas Guide, Los Angeles & Orange Counties, Digital Street Guide and Directory, 2008 Edition,by Thomas Bros. Maps, pages 992 and 993.

2000 FEET

N

2000 FEET

33.4206°N, 117.6143°W.

ALL LOCATIONS APPROXIMATE

GSIGeoSoils, Inc.

GeoSoils, Inc.

Pierce Development W.O. 6442-A-SC

301 Cazador Lane, San Clemente October 10, 2012

File:e:\wp9\oc\6400\6442a.ugr Page 4

It is GSI’s understanding that the existing single-story residence will be dismantled and fourtwo-story apartments, with attached two-car garages, along with associated improvementsare proposed to be constructed. Structural loads are assumed to be typical for this typeof construction.

FIELD REVIEW

As indicated above, our current evaluation consisted a brief field review of the site toassess current conditions. The property appeared similar to its previous condition;however, numerous remodeling improvements to the existing dwelling were noted.

FAULTING/REGIONAL SEISMICITY

The closest known active fault to the site is the offshore segment of the Newport-Inglewoodfault. A review of Blake (2000) indicates that the offshore segment of theNewport-Inglewood fault zone is approximately 4.5 miles from the site. The site is notwithin an Alquist-Priolo Earthquake Fault Zone (Bryant and Hart, 2007). Thus, the potentialfor fault rupture to occur at the site is considered very low. However, it is important to keepin perspective that in the event of an upper bound earthquake occurring on any of thenearby major faults, strong ground shaking would occur in the subject site's general area.Potential damage to any structure(s) would likely be greatest from the vibrations andimpelling force caused by the inertia of a structure's mass than from those induced by theground motion discussed above. This potential would be no greater than that for otherexisting structures and improvements in the immediate vicinity.

A probabilistic seismic hazards analysis was performed using the 2008 InteractiveDeaggregations (2010 Beta) Seismic Hazard Analysis tool available at the USGS website(https://geohazards.usgs.gov/deaggnit/2008/) which evaluates the site specificprobabilities of exceedance for selected spectral periods. Based on a review of these data,and considering the relative seismic activity of the southern California region, aprobabilistic horizontal ground acceleration (PHGA) of 0.28g and 0.52g were calculated.These values were chosen as they correspond to a 10 percent and 2 percent probabilityof exceedance in 50 years, respectively.

Seismic Shaking Parameters

Based on the site conditions, the following table summarizes the site-specific designcriteria obtained from the 2010 CBC (CBSC, 2010), Chapter 16 Structural Design,Section 1613, Earthquake Loads. The computer program Seismic Hazard Curves andUniform Hazard Response Spectra, provided by the United States Geologic Survey(U.S.G.S.) was utilized for design. The short spectral response utilizes a period of0.2 seconds.

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2010 CBC SEISMIC DESIGN PARAMETERS

PARAMETER VALUE2010 CBC

REFERENCE

Site Class C Table 1613.5.2

sSpectral Response - (0.2 sec), S 1.42g Figure 1613.5(1)

1Spectral Response - (1 sec), S 0.52g Figure 1613.5(2)

aSite Coefficient, F 1.0 Table 1613.5.3(1)

vSite Coefficient, F 1.3 Table 1613.5.3(2)

Maximum Considered Earthquake Spectral

MSResponse Acceleration (0.2 sec), S1.42g

Section 1613.5.3(Eqn 16-36)

Maximum Considered Earthquake Spectral

M1Response Acceleration (1 sec), S0.67g

Section 1613.5.3(Eqn 16-37)

5% Damped Design Spectral Response

DSAcceleration (0.2 sec), S0.95g

Section 1613.5.4(Eqn 16-38)

5% Damped Design Spectral Response

D1Acceleration (1 sec), S0.45g

Section 1613.5.4(Eqn 16-39)

GENERAL SEISMIC DESIGN PARAMETERS

Distance to Seismic Source(Newport-Inglewood - Offshore Segment)

4.5 mi. (7.3 km)

Upper Bound Earthquake(Newport-Inglewood - Offshore Segment) WM 6.9*/7.1**

Probabilistic Horizontal Ground Acceleration ([PHGA]10% and 2% probability of exceedance in 50 years,respectively)

0.28g/0.52g

* International Conference of Building Officials (ICBO, 1998); ** Cao, et al. (2003)

Conformance to the criteria above for seismic design does not constitute any kind ofguarantee or assurance that significant structural damage or ground failure will not occurin the event of a large earthquake. The primary goal of seismic design is to protect life, notto eliminate all damage, since such design may be economically prohibitive. Cumulativeeffects of seismic events are not addressed in the 2010 CBC (CBSC, 2010) and regular

wmaintenance and repair following locally significant seismic events (i.e., M 5.0) will likelybe necessary.

GROUNDWATER

Subsurface water was not encountered within the property during field work performed inpreparation of GSI (2007). Regional groundwater is estimated at about sea level, orapproximately 130 feet below the site. However, according to the historical highgroundwater map of the San Clemente Quadrangle (CGS, 2002b), groundwater may beas shallow as 10 feet from the surface. Groundwater is not anticipated to adversely affectsite development although the possibility of encountering groundwater during grading

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operations does exist. The recommendations contained in this report should beincorporated into final design and construction to minimize future groundwater issues.These observations reflect site conditions at the time of our investigation and do notpreclude future changes in local groundwater conditions from excessive irrigation,precipitation, or that were not obvious at the time of our investigation. However, based onthe permeability contrasts between any proposed fill and formational materials, perchedgroundwater conditional may develop in the future due to excess irrigation, poor drainageor damaged utilities, and should be anticipated. Should manifestations of this perchedcondition (i.e., seepage) develop in the future, this office could assess the conditions andprovide mitigative recommendations, as necessary. The potential for perched water tooccur after development should be disclosed to all interested parties and owners.

PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS

Based on our review, engineering and geologic analyses, it is GSI’s opinion that theproposed new residential development and appurtenant structures are suitable for the site,provided existing undocumented fill is not relied upon for structural support. This wouldinclude the buildings, retaining walls, and other settlement-sensitive improvements. Theproposed development is not anticipated to adversely affect nearby properties, providedour recommendations are properly implemented. The following recommendationsconsider these, as well as other aspect of site design and construction, and should beincorporated into the construction plans and details. This review is preliminary in nature,and may need to be revised, once final project plans are available. GSI does not consultin the area of safety engineering.

EARTHWORK CONSTRUCTION RECOMMENDATIONS

General Grading

All grading should conform to the guidelines presented in the 2010 CBC (CBSC, 2010), theCity, and Appendix B (this report), except where specifically superceded in the text of thisreport. When code references are not equivalent, the more stringent or adopted codeshould be followed. During earthwork construction, all site preparation and the generalgrading procedures of the contractor should be observed and the fill selectively tested bya representative(s) of GSI during the removal of the previous weathered fill. If unusual orunexpected conditions are exposed in the field, they should be reviewed by this office and,if warranted, modified and/or additional recommendations will be offered. All applicablerequirements of local and national construction and general industry safety orders, theOccupational Safety and Health Act (OSHA), and the Construction Safety Act should bemet.

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Demolition/Grubbing

1. The existing foundation and any surrounding structures not protected in placeshould be demolished and completely removed from the area.

2. Vegetation, and any miscellaneous debris should be removed from the areas ofproposed grading.

3. Any previous foundations, irrigation lines, or other subsurface structures uncoveredduring the recommended removal should be observed by GSI so that appropriateremedial recommendations can be provided.

4. Cavities or loose soils remaining after demolition and site clearance should becleaned out and observed by the soil engineer. The cavities should be replacedwith fill materials that have been moisture conditioned to at least optimum moisturecontent and compacted to at least 92 percent of the laboratory standard (ASTMD 1557).

Treatment of Existing Ground in Fill Areas

It should be noted that using a pier/grade beam foundation with a structural slab requiresonly minimal remedial grading for the support of the proposed residences, garage slabs,or retaining walls. However, site improvements not founded nor supported by either drilledpiers or formation (cut) will retain some potential for settlement. In addition, the soilcontact between the pier supported slabs and footings may, following an earthquake,become “gapped.” These unsupported improvements should therefore be limited toancillary improvements such as walkways and planters. Within the living area and garagearea, pad grade should be cleaned of any vegetation/debris, moisture conditioned (asnecessary), proof rolled and compacted to at least 92 percent relative compaction (ASTMD 1557) in the upper 3 feet prior to foundation construction. If formational soils areencountered within the new foundation excavations, the soil beneath the footing shouldbe removed to at least 2 feet below the bottom of the footing and replaced with compactedfill. If settlement cannot be tolerated for any improvements that are settlement-sensitive,they may also require deep foundations, as indicated by the architect. Areas to receivecompacted fill should be scarified, moisture conditioned and compacted to at least92 percent relative compaction per ASTM D 1557. It is possible existing fills may be toowet to recompact, and may require some drying-back, or mixing with drier soils, in orderto achieve required minimum compaction. This may increase the grading duration, andwill need to be considered during planning. Existing construction or manmade objects ofany appreciable size should be removed from the fill during processing. Utilities that aresupported within fill, which are in turn supported by beach deposits, should either be madeto hang from the bottom of the structural slab/grade beams or flexible enough to tolerateanticipated deformations.

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Fill Placement

1. Fill materials should be cleansed of major vegetation and debris prior to placement.

2. Fill materials should be brought to at least optimum moisture content, placed in thin6- to 8-inch lifts and mechanically compacted to obtain a minimum relativecompaction of 9 percent of the laboratory standard.

3. Any oversized rock materials greater than 12 inches in diameter should be placedunder the recommendations and supervision of the geotechnical consultant and/orremoved from the site. Such materials should not be placed within 10 feet of finishgrade. General recommendations for placement of oversize materials is presentedbelow and are contained in Appendix B (General Earthwork, Grading Guidelinesand Preliminary Criteria). Should significant amounts of oversize rock beencountered, recommendations for rock fill placement should be adhered to.

4. Any import materials should be observed and evaluated for suitability by the soilsengineer prior to placement on the site. If soil importation is planned, a sample ofthe soil should be evaluated by this office prior to importing, to evaluatecompatibility with the onsite soils and the recommendations presented in thisreport. At least three business days of lead time should be allowed by builders orcontractors for proposed import submittals. This lead time will allow for particle sizeanalysis, specific gravity, relative compaction, expansion testing, and blendedimport/native characteristics as deemed necessary. Import soils for a fill cap shouldbe low expansive (E.I. less than 50) or less, and not be more corrosive than onsitesoils. Foundation designs may be altered if import materials have a greaterexpansion value than the onsite materials encountered in this investigation.

Slopes

Significant new slopes are not planned for the subject development. Minor interiorelevation differentials within the project are planned to be retained by structural walls. Allslopes require normal and regular care and maintenance for satisfactory performance.

Transition Areas

Based upon the existing conditions and our understanding of the proposed development,cut/fill transitions are not anticipated. However, guidelines for such are presented inAppendix B, should this condition arise.

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SHORING OF EXCAVATIONS

Should the need for excavation adjacent to existing structures/roads evolve during projectdevelopment, temporary shoring of vertical excavations may be necessary. Werecommended that temporary slopes be retained either by a cantilever shoring system(limited to about 15 feet) deriving passive support from cast-in-place soldier piles(lagging-shoring system) or a restrained tie-back and pile system. Temporary shoring mayalso utilize cross-bracing and/or rakers if space is available for these types of shoringfeatures. Based on our experience with similar projects in the vicinity, if lateral movementon the order of 1 inch, or more, of the shoring system, or height exceeding 15 vertical feetof retained material cannot be designed for or tolerated, we recommend the utilization ofa tie-back, internal braced, or raked shoring system in lieu of cantilever system. Shoringof excavations of this size is typically performed by specialty contractors with knowledgeof the vicinity. We recommend that shoring contractors provide the excavation shoringdesign. However, for the purpose of temporary shoring design parameters, we haveprovided the lateral earth pressures in Figure 2.

Please note, the use of anchors may not be feasible on this site due to the location ofadjacent existing foundation, roadways, and utilities north of the site. If desired, additionalrecommendations will be provided for bracing, rakers, etc., if needed. Since design ofretaining is sensitive to surcharge pressures behind the excavation, we recommend thatthis office be consulted if unusual load conditions are anticipated. Care should beexercised when excavating into the on-site soils since caving or sloughing of thesematerials is possible. Field testing of tie-backs (if used) and observation of soldier pileexcavations should be performed during construction. Information regarding foundationson either side of the property may be needed to evaluate temporary shoring surcharges.Monitoring of shored excavations is recommended for the time the shoring is in place untilit is removed.

Shoring of the excavation is the responsibility of the contractor. Extreme caution shouldbe used to reduce damage to existing structure(s) and utilities caused by settlement orreduction of lateral support. Accordingly, we recommend that the foundations of adjacentstructures be surveyed prior to and during construction to evaluate the effects of shoringon these structures. Photo documentation of pre-construction conditions is also advised.Monitoring of the adjacent improvements (surveys, vibrations, etc.) should be considered.

Open Excavations

Temporary cuts should be constructed at a gradient of 1½ :1 (h:v), or flatter, for slopesexposing existing fill or beach sediments, per CAL-OSHA for Type C soils, up to 20 feethigh. Construction materials and/or stockpiled soil should not be stored within 5 feet ofthe top of any temporary slope. Temporary/permanent provisions should be made todirect any potential runoff away from the top of temporary slopes. Temporary slopesshould be evaluated during construction by the Geotechnical Engineer for any comments,

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or revisions to this recommendation. Removals and/or temporary cuts should be madewith sufficient space to allow for subdrains and/or wall back drains as recommended in thisreport. Temporary shoring/slopes should have a minimum factor-of-safety of 1.25. Ifgroundwater from tidal fluctuations is retained behind shoring, the scenario should beevaluated such that the full hydrostatic pressure is considered.

Lateral Pressure - Temporary Shoring

The active pressure to be utilized for temporary trench/wall shoring design may becomputed by the rectangular active pressure (pounds per square foot [psf]) as shown onFigure 2. Passive pressure may be computed as an equivalent fluid having a given densityshown on Figure 2.

The temporary shoring criteria, presented herein and on Figure 2, assumes that hydrostaticpressure is not allowed to build up behind excavation walls. If water is allowed toaccumulate behind walls, an additional hydrostatic pressure surcharge should be added.This may occur if temporary shoring walls are used in tidal fluctuation areas.

These recommendations are for temporary excavation walls up to 15 feet high. Activeearth pressure may be used for trench wall design, provided the wall is not restrained fromminor deflections. An empirical equivalent fluid pressure approach may be used tocompute the horizontal pressure against the wall. Appropriate fluid unit weights areprovided for specific slope gradients of the retained material: these do not include othersuperimposed loading conditions such as traffic, structures, seismic events, expansivesoils or adverse geologic conditions.

For restrained excavation walls greater than 10 feet in height, and remaining open for120 days, or more, a seismic increment of 19H (uniform pressure [where “H” is the heightof the wall]) may be considered for level backfill excavation as a uniform pressure. Forwalls, this seismic surcharge or increment should be applied at 0.6H up from the bottomof the wall to the height of retained earth materials. If the cantilever wall condition is used,an inverted triangular distribution should be used in the wall evaluation.

Excavation Observation and Monitoring (All Excavations)

When excavations are made adjacent to an existing structure (i.e., utility, road or building)there is a risk of some damage to that structure even if a well designed system ofexcavation and/or shoring, is planned and installed. We recommend, therefore, that asystematic program of observations be made before, during, and after construction todetermine the effects (if any) of construction on the existing structures.

We believe that this is necessary for two reasons: First, if excessive movements (i.e., morethan ½ inch) are detected early enough, remedial measures can be taken which couldpossibly prevent serious damage to the existing structure. Second, the responsibility for

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damage to the existing structure can be determined more equitably if the cause and extentof the damage can be determined more precisely.

Monitoring should include the measurement of any horizontal and vertical movements ofboth the existing structures and the shoring and/or bracing. Locations and type of themonitoring devices should be selected as soon as the total shoring system is designedand approved. The program of monitoring should be agreed upon between the projectteam, the site surveyor and the Geotechnical Engineer-of-Record, prior to excavation.

Reference points on the existing structures or improvements should be placed as low aspossible on the exterior walls of buildings adjacent to the excavation. Exact locations maybe dictated by critical points within the structure, such as bearing walls or columns forbuildings; and surface points on roadways and sidewalks near the top of the excavation.The points on the shoring should be placed under or very near the points on thestructures.

For a survey monitoring system, an accuracy of a least 0.01 foot should be required.Reference points should be installed and read initially prior to excavation. The readingsshould continue until all construction below ground has been completed and the backfillhas been brought up to final grade.

The frequency of readings will depend upon the results of previous readings and the rateof construction. Weekly readings could be assumed throughout the duration ofconstruction with daily readings during rapid excavation near the bottom and at criticaltimes during the installation of shoring or support. The reading should be plotted by theSurveyor and then reviewed by the Geotechnical Engineer.

In addition to the monitoring system, it would be prudent for the Geotechnical Engineerand the Contractor to make a complete inspection of the existing structures both beforeand after construction. The inspection should be directed toward detecting any signs ofdamage, particularly those caused by settlement. Notes should be made and picturesshould be taken where necessary.

Observation

It is recommended that all excavations be observed by the Geologist and/or GeotechnicalEngineer. Any fill which is placed should be approved, tested, and verified if used forengineered purposes. Temporary trench excavations should be observed by the Geologistand/or Geotechnical Engineer. Should the observation reveal any unforseen hazard, theGeologist or Geotechnical Engineer will recommend treatment. Please inform GSI at least24 hours prior to any required site observation.

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Monitoring Existing, Offsite Improvements

It is recommended that existing, offsite improvement be inspected prior to the start ofearthwork and be monitored during and at the conclusion of grading to determine ifearthwork at the site has influenced the stability of said improvements. Pressure testingof nearby gravity, as well as pressured, utilities may be warranted following developmentto evaluate if site construction has interrupted these buried improvements. In addition tothe above, monitoring of the vibrations induced by onsite equipment and constructionactivity should be considered.

PRELIMINARY FOUNDATION DESIGN RECOMMENDATIONS

General

The foundation design and construction recommendations are based on laboratory testingand engineering analysis of onsite earth materials by GSI. The foundation systems maybe used to support the foundation improvements to the development, provided they arefounded on shallow engineered fills of less than 5 feet in total thickness (recompacted)overlying formational (bedrock) earth materials only (i.e., not on undocumented fill placedon bedrock). These recommendations are provided for the shallow engineered fillcontingency, which has a low likelihood of occurring onsite. The proposed foundationsystems should be designed and constructed in accordance with the guidelines containedin the 2010 CBC, including those for expansive soils (the Plasticity Index [P.I.] of site soilshas been tested to range from 10 to 19; therefore, on a preliminary basis, a weighted P.I.= 19 may be assumed). The foundation recommendations may be incorporated into apier supported design.

Concrete

Soils with moderate levels (S1) of sulfate content are present. Concrete with a maximum0.5 water to cement ratio (f’c >4,000 psi) is recommended per 2010 CBC, as well as ACI318-08. These preliminary recommendations should be reviewed by a corrosion engineer.

Bearing Capacity for Spread Footings

Analyses indicate that an allowable bearing value of 1,500 psf may be used for design offootings on medium expansive clayey soil which maintain a minimum width of 12 inches(continuous) and 24 inches square (isolated), and a minimum depth of at least 12 inchesinto formation. Note footings may be embedded into low to medium expansive soil, if thefoundation meets the criteria for expansive soil design as indicated by the 2010 CBC andhas a minimum embedment of 18 inches into engineered fill comprised of these earthmaterials and no undocumented fill, slopewash, alluvium, or excessive fill overlies thebedrock. Regardless, the foundations should be designed for expansive soil conditions

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The bearing value may be increased by 200 psf per additional foot in depth to a totalmaximum bearing value of 2,500 psf. No increase in bearing for footing width should beused on this site. The above value may be increased by one-third for transient loads suchas seismic or wind. This assumes that footings are bearing into recompacted fill(engineered fill), overlying formational soils/bedrock.

Lateral Resistance

1. Conventional footing passive earth pressure for level conditions in recompacted fill(engineered fill) may be computed as an equivalent fluid having a density of 200 pcfper foot of embedment, to a maximum earth pressure of 2,000 psf. Passive earthpressure for sloped toe conditions may be computed as an equivalent fluid havinga density of 150 pcf, to a maximum earth pressure of 1,500 psf.

2. Based on previous shear testing, an allowable coefficient of friction between soiland concrete of 0.3 may be used with the net dead load forces. If pier supported,no frictional resistance should be used between soil and concrete footings or slabswhen computing total lateral resistance.

3. When combining passive and frictional resistance, the passive resistance should bereduced by one-third.

Construction

The foundation construction recommendations are presented as a minimum criteria froma geotechnical viewpoint. The site soils generally possess a medium expansion potential.Accordingly, the foundation construction recommendations are for soils which possessmedium expansion potentials. Recommendations by the project's design-structuralengineer or architect, which may exceed the soils engineer's recommendations, shouldtake precedence over the minimum requirements and should at all aspects meet or exceedthe requirements as expressed in the 2010 CBC.

Fill Settlement

Due to the anticipated compressive nature of existing silty to clayey sand fill soil, nosignificant new fill should be placed on the existing fill without mitigation. Mitigation ofexisting fill was outlined in GSI (2007). It is estimated that improvements placed intounmitigated undocumented fill soil may exceed ½ to 1½ inches of differential settlement,depending on the new loads. Reverse surface drainage is possible with fill settlement.

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DRILLED PIER AND GRADE BEAM FOUNDATION RECOMMENDATIONS

The proposed residential development/garage and retaining walls underlain by left-in-placeundocumented artificial fill, may be supported by a drilled, cast-in-place, concrete pier andgrade beam system (drilled piers) with structural concrete floors. All drilled piers shouldextend a minimum of 5 feet into competent formational materials. Actual pier designshould be finalized by the project’s structural engineer and the structural capacity of thepier(s) used. The structural strength of the piers should be checked by the structuralengineer or civil engineer specializing in structural analysis. Pier holes should be drilledstraight and plumb. Locations (both plan and elevation) and plumbness should be thecontractors responsibility.

The grade beam should be at a minimum of 24 inches by 24 inches in cross section andsupported by drilled piers, a minimum of 18 inches in diameter which are placed at amaximum spacing of 8 feet on center and at the location supporting all structural columns.The design of the grade beam and piers should be in accordance with therecommendations of the project structural engineer, and utilize the geotechnicalparameters herein. Down drag of piers should be taken into consideration if fill isleft-in-place and exceeds 5 feel in thickness. This down drag should be equivalent to thecohesion of the earth material or approximately 300 psf for fill, for reasonable conservatism.

Minimum Caisson Diameter 1 to 4 feet Other diameters can be considered upon request.

Lateral Passive Resistance (applicable belowthe point of fixity only)

Artificial Fill - 180 lb/ft per foot of caisson depth (since the fill is2

expansive), to a maximum value of 2,200 lb/ft - increase by one-third2

for short duration wind and seismic loading

Lateral Passive Resistance (applicable belowthe point of fixity only)

Bedrock - 500 lb/ft per foot of caisson depth, to a maximum value of2

4,500 lb/ft - static only and should not be relied upon due to2

densification and/or liquefaction if not recompacted or mitigated.

Allowable Axial Capacity (applicable belowthe point of fixity)

Tip Capacity in Bedrock: 4,500 lb/ft - increase by one-third for short2

duration wind or seismic loading, assuming clean pier bottoms.

Point of Fixity Approximately 3 feet below the bedrock contact.

Allowable Axial (Vertical) Loads on Drilled Shaft Foundations

We recommend that drilled shaft foundations supporting the proposed vertical dead andlive loads derive support from shaft friction in fill and formational deposits only. We furtherrecommend an allowable end-bearing load (formation only) resist both dead plus liveloads. It should be noted that this design requires the need for cleaning the bottoms ofdrilled excavations and in order to rely on any tip bearing for vertical support.

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To support axial loads, which were assumed to be on the order of 10 to 130 kips per pierand additional 18 kips for seismic (axial), we recommend a minimum embedment depthof 30 to 35 feet (minimum 5 feet into formational earth materials/bedrock) for a 12- to36-inch diameter pier. Pier settlements of ¼ to a of an inch should be anticipated followingconstruction of the piers under the design loads.

Lateral Loads on Drilled Shaft Foundation

Resistance to lateral loads applied to the drilled shaft is developed through deflection inthe pier, which mobilizes the reaction of the soil into which the drilled pier is embedded.The resisting pressure applied by the soil to a pier depends upon the relative stiffness ofthe pile and soil, as well as depth of embedment.

Failure of a laterally-loaded pier takes place either when the maximum bending momentin the loaded pier reaches the ultimate or yield resistance of the pier section, or when thelateral earth pressures reach the ultimate lateral resistance of the soil along the total lengthof the pier. For purposes of definition, failure of piers with relatively “short embedment”takes place when the pier rotates as a unit with respect to a point located close to its toe.Failures of piers with relatively “long embedment” occur when the maximum bendingmoment applied to the pier exceeds the yield resistance of the pier section, and a plastichinge forms at the section of maximum bending moment.

In order to determine the structural requirements and load deformation characteristics ofthe proposed concrete piers, we would suggest the elastic theory approach developed byMatlock and Reese (1960). We have assumed that lateral loads acting upon the assumed12- to 36-inch diameter piers will be on the order of 15 to 20 kips per pile.

Tiebacks and Lateral Pier Loads

The piers for support of the residential development/garage will gain their lateral supportfrom both the existing artificial fill and the underlying formation (bedrock). GSI hasevaluated 12- and 24-inch diameter piers for a fixed-head lateral capacity given the loadsassumed as assumed in this preliminary stage of design. The lateral pier deflection understatic soil and assumed structural loads was limited to 1 inch, or less. To reduce thepotential for distress on the improvements in this area, tiebacks may be added to selectedpiers. The tiebacks or bracing, if used, will likely reduce the deflection of the foundationpiers to less than ¼ inch. Tiebacks should have a bonded length embedded into theformation (Capistrano Formation) a minimum of 25 feet. They should have a batter of20 degrees from the horizontal (2.75:1 [h:v]). If tiebacks are used in conjunction with piles,they should be made 1- to 3-pier diameters from the top fo the pile and above the point offixity. Tiebacks should not be installed into piles with “cold joint” pours (i.e., two-pourpiles).

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Tieback static loads are unknown and may be on the order of 50 to 100 kips, and theallowance for 25 percent increase for transient seismic or wind loads should be includedin the seismic design of the tiebacks. Select tiebacks should be tested to a minimum of80 percent of the design ultimate strength. Creep of the selected tiebacks should bemonitored for at least 24 hours. All production tiebacks should be proof tested. Alltiebacks will consist of DYWIDAG system international (DSI) anchors with Type Cdouble-corrosion protection.

Creep Zone and Creep Load

The creep zone may be considered as a 1- to 15-foot vertical zone below a given pointon the edge of the level pad area, and projected upward, parallel to a slope face. Thecreep load projected on the area of the grade beam should be taken as an equivalent fluidapproach, having a density of 60 pcf. For the pier, it should be taken as a uniform load of1,000 pounds per linear foot of drilled pier depth, located within the creep zone.

Point of Fixity

The point of fixity should be located at a distance equivalent to one-third of the piers lengthbelow the bottom of the grade beam or at the location of maximum bending movement,as evaluated by the designer.

CIDH (Cast-in Drilled Hole) Construction

1. The excavation and installation of the drilled piers should be observed anddocumented by the project Geotechnical Engineer to verify the recommendeddepth.

2. The drilled holes should be cased, specifically below the water table (if present) toprevent caving. The bottom of the casing should be at least 4 feet below the top ofthe concrete as the concrete is poured and the casing is withdrawn. Dewateringmay be required for concrete placement if significant seepage or groundwater isencountered during construction. The bottom of this pump hose shall consist of asteel pipe at least 15 feet in length. To begin placement, this pipe will be placed onthe bottom of the excavation. As the water is forced to the top of the excavation, itshall be pumped out of the excavation so that it will not flow into the adjacent openexcavations. This should be considered during project planning. The bottom of thedrilled pier should be cleared of any loose or soft soils before concrete placement.

3. The concrete shall be allowed to flow out of the excavation until the concreteappears fresh and clean.

4. The exact depths of piers should be determined during the final precise gradingplan review.

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5. Proper low slump concrete (cement appropriate for S1 conditions per the2010 CBC, which refers to ACI 318-08) with a maximum water-cement ratio of 0.5(f’c >4,000 psi) should be used, and should be delivered through tremie pipe. Werecommend that concrete be placed through the tremie pipe immediatelysubsequent to approved excavation and steel placement. Care should be taken toprevent striking the walls of the excavations with the tremie pipe during concreteplacement.

6. All footing excavations should be observed and approved by the geotechnicalconsultant prior to placement of concrete forms and reinforcement.

7. Drilled pier steel reinforcement cages should have spacers to allow for a minimumspacing of steel from the side of the pier excavation. All reenforcing bars should beepoxy coated due to the corrosive environment. Epoxy coated steel in below gradewalls and grade beams is anticipated and should be evaluated by a structural andcorrosion consultants.

8. During pier placement, concrete should not be allowed to free fall more than 5 feet.

9. Concrete used in the foundation should be tested by a qualified materials testingconsultant for strength and mix design.

Drilled Pier and Grade Beam Foundation Settlement

Drilled pier and grade beam foundations should be designed to minimally accommodatepost-construction settlement of ¼ to a inch over a 40-foot horizontal span or between theheaviest/lightest loaded piers.

Corrosion and Concrete Mix

Upon completion of grading, laboratory testing should be performed of site materials forcorrosion to concrete and corrosion to steel. Additional comments may be obtained froma qualified corrosion engineer at that time. Given the environment, it is reasonablyassumed that all steel will be epoxy-coated corrosion protected. The need for this shouldbe confirmed by the architect and structural engineer.

PIER SUPPORTED STRUCTURAL SLABS

Prior to construction of slab-on-grade floors, the upper 12 inches of the subgrade shouldbe scarified moisture-conditioned to near-optimum water content and compacted to atleast 92 percent relative compaction and moisture conditioned as previously discussed.The slab subgrade should be non-yielding and rolled smooth prior to the placement offorms or reinforcing steel. Structural floor slabs to span unsupported between grade

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beams (areas of existing fill) should minimally be at least 5 inches in thickness andreinforced at a minimum of No. 4 bars at 12 inches on center; however, these minimalrecommendations may be superceded by more onerous design provided by the structuralslab designer. This assumes that settlement has removed soil slab support between gradebeams. Therefore, the frictional contribution of slabs to total lateral resistance should beneglected. Epoxy-coating slab reinforcement for corrosion protection is anticipated.Utilities, if tied to the under beams or slab, should have sufficient capacity such that theyare able to either be: a) flexible to move with soil settlement (static and/or seismic); or, b)be entirely supported on the slabs with hangers and separated from soil with a weak (lowstrength) filler.

SOIL MOISTURE TRANSMISSION CONSIDERATIONS

Near-surface site soils are generally medium in expansion potential, based onASTM D 4829. Accordingly, GSI has evaluated the potential for vapor or watertransmission through the slabs, in light of typical industrial/commercial floor coverings andimprovements. Please note that typical slab moisture emission rates, range from about2 to 27 lbs/ 24 hours/1,000 square feet from a typical slab (Kanare, 2005), while floorcovering manufacturers generally recommend about 3 lbs/24 hours as an upper limit. Therecommendations in this section are not intended to preclude the transmission of water orvapor through the foundation or slabs. These recommendations may be exceeded orsupplemented by a water “proofing” specialist, project architect, or structural consultant.Thus, the client will need to evaluate the following in light of a cost versus benefit analysis(owner complaints and repairs/replacement), along with disclosure to allinterested/affected parties. These recommendations do not consider the requirements forsensitive or other specialized equipment that may be utilized within the building. Ifrequired, GSI can provide supplemental recommendations to address specializedequipment and/or building uses.

Considering the E.I. test results, anticipated typical water vapor transmission rates, floorcoverings and improvements (to be chosen by the client) that can tolerate those rateswithout distress, the following alternatives are provided:

• Concrete slabs should be a minimum of 5 inches thick.

• Concrete slab underlayment should consist of a 10-mil to 15-mil vapor retarder, orequivalent, with all laps sealed per the 2010 CBC (CBSC, 2010) and themanufacturer’s recommendation.

• The 10- to 15-mil vapor retarder should comply with ASTM E 1745 - Class A or Bcriteria, and shall be installed in accordance with ASTM 1643 and per therecommendations of the manufacturer, including all penetrations (i.e., pipe, ducting,rebar, etc.).

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• The vapor retarder should be overlain by a 2-inch thick layer of clean sand (SE >30). If medium expansive or gravelly soils are present, the vapor retarder shouldalso be underlain by 2 inches of clean sand (SE > 30); 4 inches total underlayment.

• Concrete should have a maximum water/cement ratio of 0.45. This does notsupercede Table 4.3.1 of Chapter 4 the ACI (2008) for corrosion or other corrosiverequirements. Additional concrete mix design recommendations should beprovided by the structural consultant and/or waterproofing specialist. Concretefinishing and workablity should be addressed by the structural consultant and awaterproofing specialist.

• Where slab water/cement ratios are as indicated above, and/or admixtures used,the structural consultant should also make changes to the concrete in the gradebeams and footings in kind, so that the concrete used in the foundation and slabsare designed and/or treated for more uniform moisture protection.

• The owner(s) should be specifically advised which areas are suitable for tile flooring,vinyl flooring, or other types of water/vapor-sensitive flooring and which are notsuitable. In all planned floor areas, flooring shall be installed per the manufacturesrecommendations.

• Additional recommendations regarding water or vapor transmission should beprovided by the architect/structural engineer/slab or foundation designer andshould be consistent with the specified floor coverings indicated by the architect.

Regardless of the mitigation, some limited moisture/moisture vapor transmission throughthe slab should be anticipated. Construction crews may require special training forinstallation of certain product(s), as well as concrete finishing techniques. The use ofspecialized product(s) should be approved by the slab designer and water-proofingconsultant. A technical representative of the flooring contractor should review the slab andmoisture retarder plans and provide comment prior to the construction of the commercialfoundations or improvements. The vapor retarder contractor should have representativesonsite during the initial installation.

DEVELOPMENT CRITERIA

Planting

Water has been shown to weaken the inherent strength of all earth materials. Only theamount of irrigation necessary to sustain plant life should be provided. Over-wateringshould be avoided as it can adversely affect site improvements, and cause perchedgroundwater conditions. Plants selected for landscaping should be light weight, deeprooted types that require little water and are capable of surviving the prevailing climate.Utilizing plants other than those recommended above will increase the potential for

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perched water, staining, mold, etc., to develop. A rodent control program to preventburrowing should be implemented. These recommendations regarding plant type,irrigation practices, and rodent control should be provided to all interested/affected parties.

Drainage

Adequate lot surface drainage is a very important factor in reducing the likelihood ofadverse performance of foundations and hardscape. Surface drainage should be sufficientto prevent ponding of water anywhere on the property, and especially near structures. Lotsurface drainage should be carefully taken into consideration during landscaping.Therefore, care should be taken that future landscaping or construction activities do notcreate adverse drainage conditions. Positive site drainage within the property should beprovided and maintained at all times. Water should be directed away from foundations andnot allowed to pond and/or seep into the ground. In general, the area within ±5 feetaround a structure should slope away from the structure, if feasible. We recommend thatunpaved lawn and landscape areas have a minimum gradient of 1 percent sloping awayfrom structures, and whenever possible, should be above adjacent paved areas.Consideration should be given to avoiding construction of planters adjacent to structures.Site drainage should be directed toward the street or other approved area(s). Although nota geotechnical requirement, roof gutters, downspouts, or other appropriate means may beutilized to control roof drainage. Downspouts, or drainage devices should outlet aminimum of 5 feet from structures or into a subsurface drainage system. Areas of seepagemay develop due to irrigation or heavy rainfall, and should be anticipated. Minimizingirrigation will lessen this potential. If areas of seepage develop, recommendations forminimizing this effect could be provided upon request.

Landscape Maintenance

Only the amount of irrigation necessary to sustain plant life should be provided.Over-watering the landscape areas will adversely affect existing and proposed siteimprovements. We would recommend that any proposed open-bottom planters adjacentto proposed structures be eliminated for a minimum distance of 10 feet. As an alternative,closed-bottom type planters could be utilized. An outlet placed in the bottom of theplanter, could be installed to direct drainage away from structures or any exterior concreteflatwork. If planters are constructed adjacent to structures, the sides and bottom of theplanter should be provided with a moisture retarder to prevent penetration of irrigationwater into the subgrade. Provisions should be made to drain the excess irrigation waterfrom the planters without saturating the subgrade below or adjacent to the planters.Consideration should be given to the type of vegetation chosen and their potential effectupon surface improvements (i.e., some trees will have an effect on concrete flatwork withtheir extensive root systems). From a geotechnical standpoint leaching is notrecommended for establishing landscaping. If the surface soils are processed for thepurpose of adding amendments, they should be recompacted to 92 percent minimumrelative compaction.

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Gutters and Downspouts

As previously discussed in the drainage section, the installation of gutters and downspoutsshould be considered to collect roof water that may otherwise infiltrate the soils adjacentto the structures. If utilized, the downspouts should be drained into PVC collector pipesor non-erosive devices that will carry the water away from the house. Downspouts andgutters are not a geotechnical requirement provided that positive drainage is incorporatedinto project design (as discussed previously).

Subsurface and Surface Water

Subsurface and surface water are generally not significantly anticipated to affect sitedevelopment, provided that the recommendations contained in this report are properlyincorporated into final design and construction and that prudent surface and subsurfacedrainage practices are incorporated into the construction plans. Perched groundwaterconditions along zones of contrasting permeabilities may not be precluded from occurringin the future due to site irrigation, poor drainage conditions, or damaged utilities, andshould be anticipated. Should perched groundwater conditions develop, this office couldassess the affected area(s) and provide the appropriate recommendations to mitigate theobserved groundwater conditions. Groundwater conditions may change with theintroduction of irrigation, rainfall, or other factors.

Site Improvements

Recommendations for exterior concrete flatwork design and construction can be providedupon request. If in the future, any additional improvements (e.g., ponds, retentionstructures, etc.) are planned for the site, recommendations concerning the geological orgeotechnical aspects of design and construction of said improvements are recommendedto be provided at that time. This office should be notified in advance of any fill placement,grading of the site, or trench backfilling after rough grading has been completed. Thisincludes any grading, utility trench, and retaining wall backfills.

Footing Trench Excavation

All footing excavations should be observed by a representative of this firm subsequent totrenching and prior to concrete form and reinforcement placement. The purpose of theobservations is to verify that the excavations are made into the recommended bearingmaterial and to the minimum widths and depths recommended for construction. If looseor compressible materials are exposed within the footing excavation, a deeper footing orremoval and recompaction of the subgrade materials would be recommended at that time.In general, deepened footings beyond the minimum depths provided herein and shownon the plans will likely be recommended, and should be anticipated. The Client may wantto consider having a representative of GSI onsite at the start of foundation trenching toevaluate the depth to competent bearing soils and provide recommendations for footing

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embedment to the contractor performing the work. Footing trench spoil and any excesssoils generated from utility trench excavations should be compacted to a minimum relativecompaction of 92 percent, if not removed from the site.

Trenching

Considering the nature of the onsite soils, it should be anticipated that caving or sloughingcould be a factor in subsurface excavations and trenching. Shoring or excavating thetrench walls at the angle of repose (typically 25 to 45 degrees) may be necessary andshould be anticipated. All excavations should be observed by one of our representativesand minimally conform to Cal-OSHA and local safety codes.

Utility Trench Backfill

1. All interior utility trench backfill should be brought to at least 2 percent aboveoptimum moisture content and then compacted to obtain a minimum relativecompaction of 92 percent of the laboratory standard. As an alternative for shallow(12-inch to 18-inch) under-slab trenches, sand having a sand equivalent value of30, or greater, may be utilized and jetted or flooded into place. Observation,probing, and testing should be provided to verify the desired results.

2. Exterior trenches adjacent to, and within, areas extending below a 1:1 planeprojected from the outside bottom edge of the footing, and all trenches beneathhardscape features and in slopes, should be compacted to at least 92 percent ofthe laboratory standard. Sand backfill, unless excavated from the trench, shouldnot be used in these backfill areas. Compaction testing and observations, alongwith probing, should be accomplished to verify the desired results.

3. All trench excavations should conform to Cal-OSHA and local safety codes.

4. Utilities crossing grade beams, perimeter beams, or footings should either passbelow the footing or grade beam utilizing a hardened collar or foam spacer, or passthrough the footing or grade beam in accordance with the recommendations of thestructural engineer.

SUMMARY OF RECOMMENDATIONS REGARDING

GEOTECHNICAL OBSERVATION AND TESTING

We recommend that observation and/or testing be performed by GSI at each of thefollowing construction stages:

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• During grading/recertification.

• During significant excavation (i.e., higher than 4 feet).

• During placement of subdrains or other subdrainage devices, prior to placing filland/or backfill.

• After excavation of building footings, retaining wall footings, and free standing wallsfootings, prior to the placement of reinforcing steel or concrete.

• Prior to pouring any slabs or flatwork, after presoaking/presaturation of buildingpads and other flatwork subgrade, before the placement of concrete, reinforcingsteel, capillary break (i.e., sand, pea-gravel, etc.), or vapor retarders(i.e., visqueen, etc.).

• During retaining wall subdrain installation, prior to backfill placement.

• During placement of backfill for area drain, interior plumbing, utility line trenches,and retaining wall backfill.

• During slope construction/repair.

• When any unusual soil conditions are encountered during any constructionoperations, subsequent to the issuance of this report.

• When any improvements, such as flatwork, spas, pools, walls, etc., are constructed.

• A report of geotechnical observation and testing should be provided at theconclusion of each of the above stages, in order to provide concise and cleardocumentation of site work, and/or to comply with code requirements.

PLAN REVIEW

Final project plans should be reviewed by this office prior to construction, so thatconstruction is in accordance with the conclusions and recommendations of this report.Based on our review, supplemental recommendations and/or further geotechnical studiesmay be warranted.

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LIMITATIONS

The materials encountered on the project site and utilized for our analysis are believedrepresentative of the area; however, soil and bedrock materials vary in character betweenexcavations and natural outcrops or conditions exposed during mass grading. Siteconditions may vary due to seasonal changes or other factors.

Inasmuch as our study is based upon our review, engineering analyses, and laboratorydata, the conclusions and recommendations presented herein are professional opinions.These opinions have been derived in accordance with current standards of practice, andno warranty is express or implied. Standards of practice are subject to change with time.This report has been prepared for the purpose of providing soil design parameters derivedfrom testing of a soil sample received at our laboratory, and does not represent anevaluation of the overall stability, suitability, or performance of the property for theproposed development. GSI assumes no responsibility or liability for work or testingperformed by others, or their inaction; or work performed when GSI is not requested to beonsite, to evaluate if our recommendations have been properly implemented. Use of thisreport constitutes an agreement and consent by the user to all the limitations outlinedabove, notwithstanding any other agreements that may be in place. In addition, this reportmay be subject to review by the controlling authorities. Thus, this report brings tocompletion our scope of services for this portion of the project.

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APPENDIX A

REFERENCES

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APPENDIX A

REFERENCES

American Concrete Institute, 2008, Building code requirements for structural concrete (ACI318-08) and commentary, reported by ACI Committee 318, dated January.

Blake, Thomas F., 2000, EQFAULT, A computer program for the estimation of peakhorizontal acceleration from 3-D fault sources; Windows 95/98 version.

Bryant, W.A., and Hart, E.W., 2007, Fault-rupture hazard zones in California, Alquist-Prioloearthquake fault zoning act with index to earthquake fault zones maps;California Geological Survey, Special Publication 42, interim revision.

California Building Standards Commission, 2010, California Building Code, California Codeof Regulations, Title 24, Part 2, Volume 2 of 2, Based on the 2009 InternationalBuilding Code, 2010 California Historical Building Code, Title 24, Part 8; 2010California Existing Building Code, Title 24, Part 10.

California Department of Transportation (Caltrans), 2006, Highway design manual,sixth edition.

California Department of Conservation, California Geological Survey (CGS), 2002a,Seismic Hazard Zones, San Clemente Quadrangle, State of California, Official Map,Scale: = 1" = 2,000', dated June 21.

_____, 2002b, Seismic Hazard Evaluation of the San Clemente 7.5 Minute Quadrangle,Orange County, California, SHZR No. 062, Historical High Groundwater Map,Sheet 1.2.

Cao, T., Bryant, W.A., Rowshandel, B., Branum, D., and Wills, C.J., 2003, The revised 2002Cal i fo rn ia probabi l ist ic seismic hazard maps, dated June,http://www.conservation.ca.gov/cgs/rghm/psha/fault_parameters/pdf/Documents/2002_CA_Hazard_Maps.pdf

GeoSoils, Inc., 2008, Response to City of San Clemente Review Sheet, Job No. ENG08-003, dated March 15, 2008, “Preliminary Geotechnical Investigation, ProposedTwo-Story, Multi-Unit Town Home Development, 301 Cazador Lane, San Clemente,California, dated May 25, 2007, W.O. 5441-A-OC”, W.O. 5441-A1-OC, datedJune 10.

_____, 2007, Preliminary geotechnical investigation, proposed two-story, multi-unit townhome development, 301 Cazador Lane, San Clemente, California, W.O. 5441-A-OC,dated May 25.

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Jones, Cahl & Associates, 2012, Grading Plans, 301 Cazador Lane, San Clemente,California, 3 Sheets, 10 Scale, Job No. 07-1758, dated August 23.

Matlock, H., and Reese, L.C., 1960, Generalized solutions for laterally loaded piles, Journalof the Soil Mechanics and Foundations Division, ASCE, Vol.86, No SM5, pp.63-91.

R. Moser Building Design, 2012, Architectural Plans, 301 Cazador Lane, San Clemente,California, 7 Sheets, Scale: ¼” = 1', Project Number: 301 Cazador 2012, datedAugust 21.

U.S. Geological Survey, 2011, Seismic Hazard Curves and Uniform Response Spectra,Version 5.1.0., dated February.

_____, 2011, 2008 Earthquake Hazards Program, 2008 Interactive Deaggregations (Beta),Earthquake Hazards Program; http://eqint.cr.usgs.gov/deaggint/2008/

http://eqint.cr.usgs.gov/deaggint/2008/

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APPENDIX B

GENERAL EARTHWORK, GRADING GUIDELINES

AND PRELIMINARY CRITERIA

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GENERAL EARTHWORK, GRADING GUIDELINES, AND PRELIMINARY CRITERIA

General

These guidelines present general procedures and requirements for earthwork and gradingas shown on the approved grading plans, including preparation of areas to be filled,placement of fill, installation of subdrains, excavations, and appurtenant structures orflatwork. The recommendations contained in the geotechnical report are part of theseearthwork and grading guidelines and would supercede the provisions contained hereafterin the case of conflict. Evaluations performed by the consultant during the course ofgrading may result in new or revised recommendations which could supercede theseguidelines or the recommendations contained in the geotechnical report. Generalizeddetails follow this text.

The contractor is responsible for the satisfactory completion of all earthwork in accordancewith provisions of the project plans and specifications and latest adopted code. In the caseof conflict, the most onerous provisions shall prevail. The project geotechnical engineerand engineering geologist (geotechnical consultant), and/or their representatives, shouldprovide observation and testing services, and geotechnical consultation during theduration of the project.

EARTHWORK OBSERVATIONS AND TESTING

Geotechnical Consultant

Prior to the commencement of grading, a qualified geotechnical consultant (soil engineerand engineering geologist) should be employed for the purpose of observing earthworkprocedures and testing the fills for general conformance with the recommendations of thegeotechnical report(s), the approved grading plans, and applicable grading codes andordinances.

The geotechnical consultant should provide testing and observation so that an evaluationmay be made that the work is being accomplished as specified. It is the responsibility ofthe contractor to assist the consultants and keep them apprised of anticipated workschedules and changes, so that they may schedule their personnel accordingly.

All remedial removals, clean-outs, prepared ground to receive fill, key excavations, andsubdrain installation should be observed and documented by the geotechnical consultantprior to placing any fill. It is the contractor’s responsibility to notify the geotechnicalconsultant when such areas are ready for observation.

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Laboratory and Field Tests

Maximum dry density tests to determine the degree of compaction should be performedin accordance with American Standard Testing Materials test method ASTM designationD-1557. Random or representative field compaction tests should be performed inaccordance with test methods ASTM designation D-1556, D-2937 or D-2922, and D-3017,at intervals of approximately ±2 feet of fill height or approximately every 1,000 cubic yardsplaced. These criteria would vary depending on the soil conditions and the size of theproject. The location and frequency of testing would be at the discretion of thegeotechnical consultant.

Contractor's Responsibility

All clearing, site preparation, and earthwork performed on the project should be conductedby the contractor, with observation by a geotechnical consultant, and staged approval bythe governing agencies, as applicable. It is the contractor's responsibility to prepare theground surface to receive the fill, to the satisfaction of the geotechnical consultant, and toplace, spread, moisture condition, mix, and compact the fill in accordance with therecommendations of the geotechnical consultant. The contractor should also remove allnon-earth material considered unsatisfactory by the geotechnical consultant.

Notwithstanding the services provided by the geotechnical consultant, it is the soleresponsibility of the contractor to provide adequate equipment and methods to accomplishthe earthwork in strict accordance with applicable grading guidelines, latest adopted codesor agency ordinances, geotechnical report(s), and approved grading plans. Sufficientwatering apparatus and compaction equipment should be provided by the contractor withdue consideration for the fill material, rate of placement, and climatic conditions. If, in theopinion of the geotechnical consultant, unsatisfactory conditions such as questionableweather, excessive oversized rock or deleterious material, insufficient support equipment,etc., are resulting in a quality of work that is not acceptable, the consultant will inform thecontractor, and the contractor is expected to rectify the conditions, and if necessary, stopwork until conditions are satisfactory.

During construction, the contractor shall properly grade all surfaces to maintain gooddrainage and prevent ponding of water. The contractor shall take remedial measures tocontrol surface water and to prevent erosion of graded areas until such time as permanentdrainage and erosion control measures have been installed.

SITE PREPARATION

All major vegetation, including brush, trees, thick grasses, organic debris, and otherdeleterious material, should be removed and disposed of off-site. These removals mustbe concluded prior to placing fill. In-place existing fill, soil, alluvium, colluvium, or rockmaterials, as evaluated by the geotechnical consultant as being unsuitable, should be



removed prior to any fill placement. Depending upon the soil conditions, these materialsmay be reused as compacted fills. Any materials incorporated as part of the compactedfills should be approved by the geotechnical consultant.

Any underground structures such as cesspools, cisterns, mining shafts, tunnels, septictanks, wells, pipelines, or other structures not located prior to grading, are to be removedor treated in a manner recommended by the geotechnical consultant. Soft, dry, spongy,highly fractured, or otherwise unsuitable ground, extending to such a depth that surfaceprocessing cannot adequately improve the condition, should be overexcavated down tofirm ground and approved by the geotechnical consultant before compaction and fillingoperations continue. Overexcavated and processed soils, which have been properlymixed and moisture conditioned, should be re-compacted to the minimum relativecompaction as specified in these guidelines.

Existing ground, which is determined to be satisfactory for support of the fills, should bescarified (ripped) to a minimum depth of 6 to 8 inches, or as directed by the geotechnicalconsultant. After the scarified ground is brought to optimum moisture content, or greaterand mixed, the materials should be compacted as specified herein. If the scarified zoneis greater than 6 to 8 inches in depth, it may be necessary to remove the excess and placethe material in lifts restricted to about 6 to 8 inches in compacted thickness.

Existing ground which is not satisfactory to support compacted fill should beoverexcavated as required in the geotechnical report, or by the on-site geotechnicalconsultant. Scarification, disc harrowing, or other acceptable forms of mixing shouldcontinue until the soils are broken down and free of large lumps or clods, until the workingsurface is reasonably uniform and free from ruts, hollows, hummocks, mounds, or otheruneven features, which would inhibit compaction as described previously.

Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical[h:v]), the ground should be stepped or benched. The lowest bench, which will act as akey, should be a minimum of 15 feet wide and should be at least 2 feet deep into firmmaterial, and approved by the geotechnical consultant. In fill-over-cut slope conditions,the recommended minimum width of the lowest bench or key is also 15 feet, with the keyfounded on firm material, as designated by the geotechnical consultant. As a general rule,unless specifically recommended otherwise by the geotechnical consultant, the minimumwidth of fill keys should be equal to ½ the height of the slope.

Standard benching is generally 4 feet (minimum) vertically, exposing firm, acceptablematerial. Benching may be used to remove unsuitable materials, although it is understoodthat the vertical height of the bench may exceed 4 feet. Pre-stripping may be consideredfor unsuitable materials in excess of 4 feet in thickness.



All areas to receive fill, including processed areas, removal areas, and the toes of fillbenches, should be observed and approved by the geotechnical consultant prior toplacement of fill. Fills may then be properly placed and compacted until design grades(elevations) are attained.

COMPACTED FILLS

Any earth materials imported or excavated on the property may be utilized in the fillprovided that each material has been evaluated to be suitable by the geotechnicalconsultant. These materials should be free of roots, tree branches, other organic matter,or other deleterious materials. All unsuitable materials should be removed from the fill asdirected by the geotechnical consultant. Soils of poor gradation, undesirable expansionpotential, or substandard strength characteristics may be designated by the consultant asunsuitable and may require blending with other soils to serve as a satisfactory fill material.

Fill materials derived from benching operations should be dispersed throughout the fillarea and blended with other approved material. Benching operations should not result inthe benched material being placed only within a single equipment width away from thefill/bedrock contact.

Oversized materials defined as rock, or other irreducible materials, with a maximumdimension greater than 12 inches, should not be buried or placed in fills unless thelocation of materials and disposal methods are specifically approved by the geotechnicalconsultant. Oversized material should be taken offsite, or placed in accordance withrecommendations of the geotechnical consultant in areas designated as suitable for rockdisposal. GSI anticipates that soils to be utilized as fill material for the subject project maycontain some rock. Appropriately, the need for rock disposal may be necessary duringgrading operations on the site. From a geotechnical standpoint, the depth of any rocks,rock fills, or rock blankets, should be a sufficient distance from finish grade. This depth isgenerally the same as any overexcavation due to cut-fill transitions in hard rock areas, andgenerally facilitates the excavation of structural footings and substructures. Should deeperexcavations be proposed (i.e., deepened footings, utility trenching, swimming pools, spas,etc.), the developer may consider increasing the hold-down depth of any rocky fills to beplaced, as appropriate. In addition, some agencies/jurisdictions mandate a specifichold-down depth for oversize materials placed in fills. The hold-down depth, and potentialto encounter oversize rock, both within fills, and occurring in cut or natural areas, wouldneed to be disclosed to all interested/affected parties. Once approved by the governingagency, the hold-down depth for oversized rock (i.e., greater than 12 inches) in fills on thisproject is provided as 10 feet, unless specified differently in the text of this report. Thegoverning agency may require that these materials need to be deeper, crushed, orreduced to less than 12 inches in maximum dimension, at their discretion.



To facilitate future trenching, rock (or oversized material), should not be placed within thehold-down depth feet from finish grade, the range of foundation excavations, future utilities,or underground construction unless specifically approved by the governing agency, thegeotechnical consultant, and/or the developer’s representative.

If import material is required for grading, representative samples of the materials to beutilized as compacted fill should be analyzed in the laboratory by the geotechnicalconsultant to evaluate it’s physical properties and suitability for use onsite. Such testingshould be performed three (3) days prior to importation. If any material other than thatpreviously tested is encountered during grading, an appropriate analysis of this materialshould be conducted by the geotechnical consultant as soon as possible.

Approved fill material should be placed in areas prepared to receive fill in near horizontallayers, that when compacted, should not exceed about 6 to 8 inches in thickness. Thegeotechnical consultant may approve thick lifts if testing indicates the grading proceduresare such that adequate compaction is being achieved with lifts of greater thickness. Eachlayer should be spread evenly and blended to attain uniformity of material and moisturesuitable for compaction.

Fill layers at a moisture content less than optimum should be watered and mixed, and wetfill layers should be aerated by scarification, or should be blended with drier material.Moisture conditioning, blending, and mixing of the fill layer should continue until the fillmaterials have a uniform moisture content at, or above, optimum moisture.

After each layer has been evenly spread, moisture conditioned, and mixed, it should beuniformly compacted to a minimum of 90 percent of the maximum density as evaluated byASTM test designation D-1557, or as otherwise recommended by the geotechnicalconsultant. Compaction equipment should be adequately sized and should be specificallydesigned for soil compaction, or of proven reliability to efficiently achieve the specifieddegree of compaction.

Where tests indicate that the density of any layer of fill, or portion thereof, is below therequired relative compaction, or improper moisture is in evidence, the particular layer orportion shall be re-worked until the required density and/or moisture content has beenattained. No additional fill shall be placed in an area until the last placed lift of fill has beentested and found to meet the density and moisture requirements, and is approved by thegeotechnical consultant.

In general, per the 1997 UBC and/or latest adopted version of the California Building Code(CBC), fill slopes should be designed and constructed at a gradient of 2:1 (h:v), or flatter.Compaction of slopes should be accomplished by over-building a minimum of 3 feethorizontally, and subsequently trimming back to the design slope configuration. Testingshall be performed as the fill is elevated to evaluate compaction as the fill core is beingdeveloped. Special efforts may be necessary to attain the specified compaction in the fillslope zone. Final slope shaping should be performed by trimming and removing loose



materials with appropriate equipment. A final evaluation of fill slope compaction shouldbe based on observation and/or testing of the finished slope face. Where compacted fillslopes are designed steeper than 2:1 (h:v), prior approval from the governing agency,specific material types, a higher minimum relative compaction, special reinforcement, andspecial grading procedures will be recommended.

If an alternative to over-building and cutting back the compacted fill slopes is selected,then special effort should be made to achieve the required compaction in the outer 10 feetof each lift of fill by undertaking the following:

1. An extra piece of equipment consisting of a heavy, short-shanked sheepsfootshould be used to roll (horizontal) parallel to the slopes continuously as fill isplaced. The sheepsfoot roller should also be used to roll perpendicular to theslopes, and extend out over the slope to provide adequate compaction to the faceof the slope.

2. Loose fill should not be spilled out over the face of the slope as each lift iscompacted. Any loose fill spilled over a previously completed slope face should betrimmed off or be subject to re-rolling.

3. Field compaction tests will be made in the outer (horizontal) ±2 to ±8 feet of theslope at appropriate vertical intervals, subsequent to compaction operations.

4. After completion of the slope, the slope face should be shaped with a small tractorand then re-rolled with a sheepsfoot to achieve compaction to near the slope face.Subsequent to testing to evaluate compaction, the slopes should be grid-rolled toachieve compaction to the slope face. Final testing should be used to evaluatecompaction after grid rolling.

5. Where testing indicates less than adequate compaction, the contractor will beresponsible to rip, water, mix, and recompact the slope material as necessary toachieve compaction. Additional testing should be performed to evaluatecompaction.

SUBDRAIN INSTALLATION

Subdrains should be installed in approved ground in accordance with the approximatealignment and details indicated by the geotechnical consultant. Subdrain locations ormaterials should not be changed or modified without approval of the geotechnicalconsultant. The geotechnical consultant may recommend and direct changes in subdrainline, grade, and drain material in the field, pending exposed conditions. The location ofconstructed subdrains, especially the outlets, should be recorded/surveyed by the projectcivil engineer. Drainage at the subdrain outlets should be provided by the project civilengineer.



EXCAVATIONS

Excavations and cut slopes should be examined during grading by the geotechnicalconsultant. If directed by the geotechnical consultant, further excavations oroverexcavation and refilling of cut areas should be performed, and/or remedial grading ofcut slopes should be performed. When fill-over-cut slopes are to be graded, unlessotherwise approved, the cut portion of the slope should be observed by the geotechnicalconsultant prior to placement of materials for construction of the fill portion of the slope.The geotechnical consultant should observe all cut slopes, and should be notified by thecontractor when excavation of cut slopes commence.

If, during the course of grading, unforeseen adverse or potentially adverse geologicconditions are encountered, the geotechnical consultant should investigate, evaluate, andmake appropriate recommendations for mitigation of these conditions. The need for cutslope buttressing or stabilizing should be based on in-grading evaluation by thegeotechnical consultant, whether anticipated or not.

Unless otherwise specified in geotechnical and geological report(s), no cut slopes shouldbe excavated higher or steeper than that allowed by the ordinances of controllinggovernmental agencies. Additionally, short-term stability of temporary cut slopes is thecontractor’s responsibility.

Erosion control and drainage devices should be designed by the project civil engineer andshould be constructed in compliance with the ordinances of the controlling governmentalagencies, and/or in accordance with the recommendations of the geotechnical consultant.

COMPLETION

Observation, testing, and consultation by the geotechnical consultant should beconducted during the grading operations in order to state an opinion that all cut and fillareas are graded in accordance with the approved project specifications. After completionof grading, and after the geotechnical consultant has finished observations of the work,final reports should be submitted, and may be subject to review by the controllinggovernmental agencies. No further excavation or filling should be undertaken without priornotification of the geotechnical consultant or approved plans.

All finished cut and fill slopes should be protected from erosion and/or be planted inaccordance with the project specifications and/or as recommended by a landscapearchitect. Such protection and/or planning should be undertaken as soon as practical aftercompletion of grading.



PRELIMINARY OUTDOOR POOL/SPA DESIGN RECOMMENDATIONS

The following preliminary recommendations are provided for consideration in pool/spadesign and planning. Actual recommendations should be provided by a qualifiedgeotechnical consultant, based on site specific geotechnical conditions, including asubsurface investigation, differential settlement potential, expansive and corrosive soilpotential, proximity of the proposed pool/spa to any slopes with regard to slope creep andlateral fill extension, as well as slope setbacks per code, and geometry of the proposedimprovements. Recommendations for pools/spas and/or deck flatwork underlain byexpansive soils, or for areas with differential settlement greater than ¼-inch over 40 feethorizontally, will be more onerous than the preliminary recommendations presented below.

The 1:1 (h:v) influence zone of any nearby retaining wall site structures should bedelineated on the project civil drawings with the pool/spa. This 1:1 (h:v) zone is definedas a plane up from the lower-most heel of the retaining structure, to the daylight grade ofthe nearby building pad or slope. If pools/spas or associated pool/spa improvements areconstructed within this zone, they should be re-positioned (horizontally or vertically) so thatthey are supported by earth materials that are outside or below this 1:1 plane. If this is notpossible given the area of the building pad, the owner should consider eliminating theseimprovements or allow for increased potential for lateral/vertical deformations andassociated distress that may render these improvements unusable in the future, unlessthey are periodically repaired and maintained. The conditions and recommendationspresented herein should be disclosed to all homeowners and any interested/affectedparties.

General

1. The equivalent fluid pressure to be used for the pool/spa design should be60 pounds per cubic foot (pcf) for pool/spa walls with level backfill, and 75 pcf fora 2:1 sloped backfill condition. In addition, backdrains should be provided behindpool/spa walls subjacent to slopes.

2. Passive earth pressure may be computed as an equivalent fluid having a density of150 pcf, to a maximum lateral earth pressure of 1,000 pounds per square foot (psf).

3. An allowable coefficient of friction between soil and concrete of 0.30 may be usedwith the dead load forces.

4. When combining passive pressure and frictional resistance, the passive pressurecomponent should be reduced by one-third.

5. Where pools/spas are planned near structures, appropriate surcharge loads needto be incorporated into design and construction by the pool/spa designer. Thisincludes, but is not limited to landscape berms, decorative walls, footings, built-inbarbeques, utility poles, etc.



6. All pool/spa walls should be designed as “free standing” and be capable ofsupporting the water in the pool/spa without soil support. The shape of pool/spain cross section and plan view may affect the performance of the pool, from ageotechnical standpoint. Pools and spas should also be designed in accordancewith Section 1806.5 of the 1997 UBC. Minimally, the bottoms of the pools/spas,should maintain a distance H/3, where H is the height of the slope (in feet), from theslope face. This distance should not be less than 7 feet, nor need not be greaterthan 40 feet.

7. The soil beneath the pool/spa bottom should be uniformly moist with the samestiffness throughout. If a fill/cut transition occurs beneath the pool/spa bottom, thecut portion should be overexcavated to a minimum depth of 48 inches, andreplaced with compacted fill, such that there is a uniform blanket that is a minimumof 48 inches below the pool/spa shell. If very low expansive soil is used for fill, thefill should be placed at a minimum of 95 percent relative compaction, at optimummoisture conditions. This requirement should be 90 percent relative compactionat over optimum moisture if the pool/spa is constructed within or near expansivesoils. The potential for grading and/or re-grading of the pool/spa bottom, andattendant potential for shoring and/or slot excavation, needs to be consideredduring all aspects of pool/spa planning, design, and construction.

8. If the pool/spa is founded entirely in compacted fill placed during rough grading, thedeepest portion of the pool/spa should correspond with the thickest fill on the lot.

9. Hydrostatic pressure relief valves should be incorporated into the pool and spadesigns. A pool/spa under-drain system is also recommended, with an appropriateoutlet for discharge.

10. All fittings and pipe joints, particularly fittings in the side of the pool or spa, shouldbe properly sealed to prevent water from leaking into the adjacent soils materials,and be fitted with slip or expandible joints between connections transecting varyingsoil conditions.

11. An elastic expansion joint (flexible waterproof sealant) should be installed to preventwater from seeping into the soil at all deck joints.

12. A reinforced grade beam should be placed around skimmer inlets to providesupport and mitigate cracking around the skimmer face.

13. In order to reduce unsightly cracking, deck slabs should minimally be 4 inchesthick, and reinforced with No. 3 reinforcing bars at 18 inches on-center. All slabreinforcement should be supported to ensure proper mid-slab positioning duringthe placement of concrete. Wire mesh reinforcing is specifically not recommended.Deck slabs should not be tied to the pool/spa structure. Pre-moistening and/orpre-soaking of the slab subgrade is recommended, to a depth of 12 inches



(optimum moisture content), or 18 inches (120 percent of the soil’s optimummoisture content, or 3 percent over optimum moisture content, whichever isgreater), for very low to low, and medium expansive soils, respectively. Thismoisture content should be maintained in the subgrade soils during concreteplacement to promote uniform curing of the concrete and minimize thedevelopment of unsightly shrinkage cracks. Slab underlayment should consist ofa 1- to 2-inch leveling course of sand (S.E.>30) and a minimum of 4 to 6 inches ofClass 2 base compacted to 90 percent. Deck slabs within the H/3 zone, where His the height of the slope (in feet), will have an increased potential for distressrelative to other areas outside of the H/3 zone. If distress is undesirable,improvements, deck slabs or flatwork should not be constructed closer than H/3 or7 feet (whichever is greater) from the slope face, in order to reduce, but noteliminate, this potential.

14. Pool/spa bottom or deck slabs should be founded entirely on competent bedrock,or properly compacted fill. Fill should be compacted to achieve a minimum90 percent relative compaction, as discussed above. Prior to pouring concrete,subgrade soils below the pool/spa decking should be throughly watered to achievea moisture content that is at least 2 percent above optimum moisture content, to adepth of at least 18 inches below the bottom of slabs. This moisture content shouldbe maintained in the subgrade soils during concrete placement to promote uniformcuring of the concrete and minimize the development of unsightly shrinkage cracks.

15. In order to reduce unsightly cracking, the outer edges of pool/spa decking to bebordered by landscaping, and the edges immediately adjacent to the pool/spa,should be underlain by an 8-inch wide concrete cutoff shoulder (thickened edge)extending to a depth of at least 12 inches below the bottoms of the slabs to mitigateexcessive infiltration of water under the pool/spa deck. These thickened edgesshould be reinforced with two No. 4 bars, one at the top and one at the bottom.Deck slabs may be minimally reinforced with No. 3 reinforcing bars placed at18 inches on-center, in both directions. All slab reinforcement should be supportedon chairs to ensure proper mid-slab positioning during the placement of concrete.

16. Surface and shrinkage cracking of the finish slab may be reduced if a low slumpand water-cement ratio are maintained during concrete placement. Concreteutilized should have a minimum compressive strength of 4,000 psi. Excessive wateradded to concrete prior to placement is likely to cause shrinkage cracking, andshould be avoided. Some concrete shrinkage cracking, however, is unavoidable.

17. Joint and sawcut locations for the pool/spa deck should be determined by thedesign engineer and/or contractor. However, spacings should not exceed 6 feet oncenter.

18. Considering the nature of the onsite earth materials, it should be anticipated thatcaving or sloughing could be a factor in subsurface excavations and trenching.



Shoring or excavating the trench walls/backcuts at the angle of repose (typically 25to 45 degrees), should be anticipated. All excavations should be observed by arepresentative of the geotechnical consultant, including the project geologist and/orgeotechnical engineer, prior to workers entering the excavation or trench, andminimally conform to Cal/OSHA (“Type C” soils may be assumed), state, and localsafety codes. Should adverse conditions exist, appropriate recommendationsshould be offered at that time by the geotechnical consultant. GSI does not consultin the area of safety engineering and the safety of the construction crew is theresponsibility of the pool/spa builder.

19. It is imperative that adequate provisions for surface drainage are incorporated bythe homeowners into their overall improvement scheme. Ponding water, groundsaturation and flow over slope faces, are all situations which must be avoided toenhance long term performance of the pool/spa and associated improvements, andreduce the likelihood of distress.

20. Regardless of the methods employed, once the pool/spa is filled with water, shouldit be emptied, there exists some potential that if emptied, significant distress mayoccur. Accordingly, once filled, the pool/spa should not be emptied unlessevaluated by the geotechnical consultant and the pool/spa builder.

21. For pools/spas built within (all or part) of the 1997 Uniform Building Code (UBC)setback and/or geotechnical setback, as indicated in the site geotechnicaldocuments, special foundations are recommended to mitigate the affects of creep,lateral fill extension, expansive soils and settlement on the proposed pool/spa.Most municipalities or County reviewers do not consider these effects in pool/spaplan approvals. As such, where pools/spas are proposed on 20 feet or more of fill,medium or highly expansive soils, or rock fill with limited “cap soils” and built within1997 UBC setbacks, or within the influence of the creep zone, or lateral fillextension, the following should be considered during design and construction:

OPTION A: Shallow foundations with or without overexcavation of thepool/spa “shell,” such that the pool/spa is surrounded by 5 feet of very lowto low expansive soils (without irreducible particles greater that 6 inches),and the pool/spa walls closer to the slope(s) are designed to be freestanding. GSI recommends a pool/spa under-drain or blanket system (seeattached Typical Pool/Spa Detail). The pool/spa builders and owner in thisoptional construction technique should be generally satisfied with pool/spaperformance under this scenario; however, some settlement, tilting, cracking,and leakage of the pool/spa is likely over the life of the project.

OPTION B: Pier supported pool/spa foundations with or withoutoverexcavation of the pool/spa shell such that the pool/spa is surrounded by5 feet of very low to low expansive soils (without irreducible particles greaterthan 6 inches), and the pool/spa walls closer to the slope(s) are designed to



be free standing. The need for a pool/spa under-drain system may beinstalled for leak detection purposes. Piers that support the pool/spa shouldbe a minimum of 12 inches in diameter and at a spacing to provide verticaland lateral support of the pool/spa, in accordance with the pool/spadesigners recommendations, local code, and the 1997 UBC. The pool/spabuilder and owner in this second scenario construction technique should bemore satisfied with pool/spa performance. This construction will reducesettlement and creep effects on the pool/spa; however, it will not eliminatethese potentials, nor make the pool/spa “leak-free.”

22. The temperature of the water lines for spas and pools may affect the corrosionproperties of site soils, thus, a corrosion specialist should be retained to review allspa and pool plans, and provide mitigative recommendations, as warranted.Concrete mix design should be reviewed by a qualified corrosion consultant andmaterials engineer.

23. All pool/spa utility trenches should be compacted to 90 percent of the laboratorystandard, under the full-time observation and testing of a qualified geotechnicalconsultant. Utility trench bottoms should be sloped away from the primary structureon the property (typically the residence).

24. Pool and spa utility lines should not cross the primary structure’s utility lines (i.e.,not stacked, or sharing of trenches, etc.).

25. The pool/spa or associated utilities should not intercept, interrupt, or otherwiseadversely impact any area drain, roof drain, or other drainage conveyances. If it isnecessary to modify, move, or disrupt existing area drains, subdrains, or tightlines,then the design civil engineer should be consulted, and mitigative measuresprovided. Such measures should be further reviewed and approved by thegeotechnical consultant, prior to proceeding with any further construction.

26. The geotechnical consultant should review and approve all aspects of pool/spa and

flatwork design prior to construction. A design civil engineer should review allaspects of such design, including drainage and setback conditions. Prior toacceptance of the pool/spa construction, the project builder, geotechnicalconsultant and civil designer should evaluate the performance of the area drainsand other site drainage pipes, following pool/spa construction.

27. All aspects of construction should be reviewed and approved by the geotechnicalconsultant, including during excavation, prior to the placement of any additional fill,prior to the placement of any reinforcement or pouring of any concrete.



28. Any changes in design or location of the pool/spa should be reviewed andapproved by the geotechnical and design civil engineer prior to construction. Fieldadjustments should not be allowed until written approval of the proposed fieldchanges are obtained from the geotechnical and design civil engineer.

29. Disclosure should be made to homeowners and builders, contractors, and anyinterested/affected parties, that pools/spas built within about 15 feet of the top of aslope, and/or H/3, where H is the height of the slope (in feet), will experience somemovement or tilting. While the pool/spa shell or coping may not necessarily crack,the levelness of the pool/spa will likely tilt toward the slope, and may not beesthetically pleasing. The same is true with decking, flatwork and otherimprovements in this zone.

30. Failure to adhere to the above recommendations will significantly increase thepotential for distress to the pool/spa, flatwork, etc.

31. Local seismicity and/or the design earthquake will cause some distress to thepool/spa and decking or flatwork, possibly including total functional and economicloss.

32. The information and recommendations discussed above should be provided to anycontractors and/or subcontractors, or homeowners, interested/affected parties, etc.,that may perform or may be affected by such work.

JOB SAFETY

General

At GSI, getting the job done safely is of primary concern. The following is the company'ssafety considerations for use by all employees on multi-employer construction sites.On-ground personnel are at highest risk of injury, and possible fatality, on grading andconstruction projects. GSI recognizes that construction activities will vary on each site, andthat site safety is the prime responsibility of the contractor; however, everyone must besafety conscious and responsible at all times. To achieve our goal of avoiding accidents,cooperation between the client, the contractor, and GSI personnel must be maintained.

In an effort to minimize risks associated with geotechnical testing and observation, thefollowing precautions are to be implemented for the safety of field personnel on gradingand construction projects:

Safety Meetings: GSI field personnel are directed to attend contractor’s regularlyscheduled and documented safety meetings.



Safety Vests: Safety vests are provided for, and are to be worn by GSI personnel,at all times, when they are working in the field.

Safety Flags: Two safety flags are provided to GSI field technicians; one is to beaffixed to the vehicle when on site, the other is to be placed atop thespoil pile on all test pits.

Flashing Lights: All vehicles stationary in the grading area shall use rotating or flashingamber beacons, or strobe lights, on the vehicle during all field testing.While operating a vehicle in the grading area, the emergency flasheron the vehicle shall be activated.

In the event that the contractor's representative observes any of our personnel notfollowing the above, we request that it be brought to the attention of our office.

Test Pits Location, Orientation, and Clearance

The technician is responsible for selecting test pit locations. A primary concern should bethe technician’s safety. Efforts will be made to coordinate locations with the gradingcontractor’s authorized representative, and to select locations following or behind theestablished traffic pattern, preferably outside of current traffic. The contractor’s authorizedrepresentative (supervisor, grade checker, dump man, operator, etc.) should directexcavation of the pit and safety during the test period. Of paramount concern should bethe soil technician’s safety, and obtaining enough tests to represent the fill.

Test pits should be excavated so that the spoil pile is placed away from oncoming traffic,whenever possible. The technician's vehicle is to be placed next to the test pit, oppositethe spoil pile. This necessitates the fill be maintained in a driveable condition.Alternatively, the contractor may wish to park a piece of equipment in front of the testholes, particularly in small fill areas or those with limited access.

A zone of non-encroachment should be established for all test pits. No grading equipmentshould enter this zone during the testing procedure. The zone should extendapproximately 50 feet outward from the center of the test pit. This zone is established forsafety and to avoid excessive ground vibration, which typically decreases test results.

When taking slope tests, the technician should park the vehicle directly above or below thetest location. If this is not possible, a prominent flag should be placed at the top of theslope. The contractor's representative should effectively keep all equipment at a safeoperational distance (e.g., 50 feet) away from the slope during this testing.



The technician is directed to withdraw from the active portion of the fill as soon as possiblefollowing testing. The technician's vehicle should be parked at the perimeter of the fill ina highly visible location, well away from the equipment traffic pattern. The contractorshould inform our personnel of all changes to haul roads, cut and fill areas or other factorsthat may affect site access and site safety.

In the event that the technician’s safety is jeopardized or compromised as a result of thecontractor’s failure to comply with any of the above, the technician is required, by companypolicy, to immediately withdraw and notify his/her supervisor. The grading contractor’srepresentative will be contacted in an effort to affect a solution. However, in the interim,no further testing will be performed until the situation is rectified. Any fill placed can beconsidered unacceptable and subject to reprocessing, recompaction, or removal.

In the event that the soil technician does not comply with the above or other establishedsafety guidelines, we request that the contractor bring this to the technician’s attention andnotify this office. Effective communication and coordination between the contractor’srepresentative and the soil technician is strongly encouraged in order to implement theabove safety plan.

Trench and Vertical Excavation

It is the contractor's responsibility to provide safe access into trenches where compactiontesting is needed. Our personnel are directed not to enter any excavation or vertical cutwhich: 1) is 5 feet or deeper unless shored or laid back; 2) displays any evidence ofinstability, has any loose rock or other debris which could fall into the trench; or 3) displaysany other evidence of any unsafe conditions regardless of depth.

All trench excavations or vertical cuts in excess of 5 feet deep, which any person enters,should be shored or laid back. Trench access should be provided in accordance withCal/OSHA and/or state and local standards. Our personnel are directed not to enter anytrench by being lowered or “riding down” on the equipment.

If the contractor fails to provide safe access to trenches for compaction testing, ourcompany policy requires that the soil technician withdraw and notify his/her supervisor.The contractor’s representative will be contacted in an effort to affect a solution. All backfillnot tested due to safety concerns or other reasons could be subject to reprocessing and/orremoval.

If GSI personnel become aware of anyone working beneath an unsafe trench wall orvertical excavation, we have a legal obligation to put the contractor and owner/developeron notice to immediately correct the situation. If corrective steps are not taken, GSI thenhas an obligation to notify Cal/OSHA and/or the proper controlling authorities.