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January20,2017Mr.JeremyLipkeSiskiyouCountyDepartmentofPublicWorks1312FairlaneRoadYreka,CA96097Subject: FoundationReportAddendumNo.1 TaberFile:2011-0209 SchulmeyerGulchBridgeonOld99Highway ExistingBridgeNo.2C-0264 SiskiyouCounty,CaliforniaDearMr.Lipke,Asrequested,Crawford&Associates,Inc.(CAInc)preparedthisAddendumNo.1toTaberConsultants’FoundationReportdatedDecember3,2013fortheSchulmeyerGulchBridgeonOld99HighwayprojectinSiskiyouCounty,California.TaberConsultantswasacquiredbyCAIncin2016.ThisaddendumupdatesthePileDataTablefortheCaltransStandardClass140(Alternative“X”)12-inchsquareprecast,prestressedconcretepilesrecommendedintheTaberFoundationReport.Pleaserefertothatreportforinformationnotincludedherein.Followingisupdatedprojectinformationprovidedbyyouine-mailcommunicationsdatedDecember21,2016:

• BridgeDeckDimensions=35.85’Lx33.33’W• AbutmentSkew=12.5°• Abut.1PileCut-Off=2746.65feet• Abut.2PileCut-Off=2746.65feet• TotalService-ILimitStateLoad=123.6kips/pile

Atotaloffourpileswillbeusedateachabutment.NoscourisindicatedforthisprojectandRockSlopeProtection(RSP)willbeplacedinfrontoftheabutmentstomitigatepotentialscour.WeunderstandthattheabutmentpilefoundationsforthisprojectusetheWorkingStressDesign(WSD)method.Also,forimplementationoftheGatesFormula,theTaberFoundationReportrecommendsanominaldrivingresistancevalueof370kipstobeusedforClass140pileacceptancecriteria.ThisrequirementreflectsafactorofsafetyappliedtotheGatesFormula.However,thisisnotrequiredbyCaltransandthatrecommendationmaybeignored.

FoundationReportAddendumNo.1 SchulmeyerGulchBridgeonOld99Highway 2011-0208SiskiyouCounty,CA January20,2017

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BasedontheabovedatawepresenttheupdatedPileDataTableforCaltransStandardClass140(Alternative“X”)12-inchsquareprecast,prestressedconcretepiles.Asummaryofourrevisedpileanalysisandconstructionconsiderationsisalsopresented.

PileDataTable

Support PileTypeCut-offElev.(ft)

LRFDService-ILimitStateLoadpersupport(kips)

LRFDService-ILimitState

TotalLoadperpile

(compression)(kips)

NominalResistance

(kips)

DesignTipElev.(ft)

SpecifiedTipElev.(ft)

NominalDriving

ResistanceRequired(kips)Total Permanent

Abut-112”Squareconcrete(Class140)

2746.65 495 N/A 124 250 2704(1);2721(2) 2704 250

Abut-212”Squareconcrete(Class140)

2746.65 495 N/A 124 250 2704(1);2721(2) 2704 250

1) Design tip elevations are controlled by: (1) Compression; (2) Tension; (2) Lateral Load 2) The specified tip elevation shall not be raised above the design tip elevation for lateral load.

CLASS140(ALTERNATIVE“X”)12-INCHSQUARECONCRETEPILES

COMPRESSIVERESISTANCEANDSETTLEMENTThecompressiveresistancefortheCaltransStandardClass140(Alternative“X”)12-inchsquareprecast,prestressedconcretepileswasdeterminedusingtheAPILEPlusv2computerprogramdevelopedbyEnsoft,Inc.TheFederalHighwayAdministration(FHWA)computationmethodwasusedtoestimateaxialpilecapacity.WorkingStressDesign(WSD)methodwasusedforthisanalysis.TheService-ILimitStateLoad(124kips)wasmultipliedbyaFactorofSafetyof2.0todeterminetherequirednominalresistanceof250kipsateachabutment.Scourwasneglectedinouranalysissincenonehasbeenindicatedforthissite/projectandRSPwillbeplacedinfrontofeachabutment.Groundwaterwasmodeledatthepile-cutoffelevation.Bothendbearingandskinfrictioncontributionsareconsideredinourcompressiveresistanceanalysis.Actualcontributionstoendbearingandskinfrictionvarydependingonloadtransferalongthepileshaft.

Nosignificantlong-termpilesettlementisanticipatedatthissite.

NEGATIVESKINFRICTIONNonegativeskinfrictionisanticipatedforthepilefoundations.

TENSIONNotensionload/demandisindicatedforthepilefoundations.


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LATERALLOADANALYSISTheLPILEPlusVersion2013.7.07computerprogramwasusedtoestimatelateralpiledesignloadswhichwouldproduceapproximately¼-inchand1-inchpileheaddeflectionforapinned(free-head)conditioninthelongitudinalbridgedirection.Fortheproposedsingle-spanbridge,pileresponsewascomputedusingelasticpilestiffness(basicmodeling)withanaxialcompressionof124kipsappliedtothetopofthepile.Ap-multiplierof1.0inthelongitudinaldirectionwasusedinouranalysisbasedonasinglerowoffourpilesspacedatleast9ft.Thelateralpileanalysisdoesnotconsiderscourattheabutments.Groundwaterwasmodeledatthepile-cutoffelevation.Aminimumtipelevationof2721ftateachabutmentwasdeterminedbasedontheestimatedcriticalpilelengthandusingafactorofsafetyof1.25.Theresultsofourlateralpileanalysisinthelongitudinalbridgedirectionattheabutmentsareshowninthefollowingtable.

AbutmentPileHeadDeflectionvs.LateralLoad

PileHeadDeflection(inches)

LateralLoad(kips)

LongitudinalDirection

0.25 9.5

1.00 21.0

CONSTRUCTIONCONIDERATIONS

GENERALDrivenpilesshouldconformtoSection49-1(General)andSection49-2(DrivenPiling)oftheCaltransStandardSpecifications.Loadtestpilesanddynamicmonitoringarenotnecessary.Jettingorvibratoryhammersshouldnotbeusedtoobtainthespecifiedpilepenetration.

PILEDRIVINGSYSTEMSUBMITTALTheContractorshallprovideaPileDrivingSystemsubmittalinaccordancewithCaltransStandardSpecificationtoverifythatthepiledrivingsystemisadequate.

PILEDRIVINGACCEPTANCECRITERIAAllpilesshouldbespecifiedtopenetratetoorbelowSpecifiedTipElevationanddemonstratethenominaldrivingresistanceatfinalpenetration.Notethatthenominaldrivingresistanceisnotnecessarilythesameasthenominalresistance.VerifypilecapacityduringdrivingusingtheformulapresentedinCaltransStandardSpecificationSection49.


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DEWATERINGGroundwaterisexpectedtooccurthroughoutbedloadandsurfacematerialsbelowthecreeksurfacewaterelevation.Soilsbelowgroundwaterlevelareexpectedtobesaturatedandcapableoftransmittingsubstantialquantitiesofseepagetoopenexcavations.Thecontractorisresponsiblefordewateringand/ordikingdiversiondesignandconstructionmethods.Adequateconstructionde-wateringisexpectedtobeachievable(atlowchannelflowduringdryseasonconstruction)bymeansofdiking/diversionofsurfacewaterandtheuseofsumppumps,butcouldrequireheavypumping.Temporarydiversion/pipingofallsurfacewateraround/throughthesiteisconsideredprudent.Thebottomoftheabutmentpilefootingexcavationmaybesoft/wet.Ifneeded,theuseofcoarse,granularsoils(say,aggregatebase,drainrock,etc.)atthebaseofexcavationwouldbeexpectedtoprovideanappropriateworkingsurface.

______________________________________________________________Otherthantheitemsaddressed/revisedinthisaddendum,theforegoingdoesnotchangetheconclusions/recommendationscontainedintheoriginalreport.ThisaddendumisalsosubjecttothelimitationsandgeneralconditionscontainedwithinthereferencedFoundationReportdatedDecember3,2013.Weappreciatethisopportunitytobeofservice.Pleasecallifyouhavequestionsorrequireadditionalinformation.Crawford&Associates,Inc.W.EricNichols,SeniorProjectManagerC.E.G.2229P.E.82103

3911 West Capitol AvenueWest Sacramento, CA 95691-21 16(916) 371-1690(707) 575-1568Fax (916) 371-7265www.tabe rconsu ltants. com

Foundation RepoÉSchulmeyer Gulch Bridge on Old 99 HighwayExisting Bridge No. 2C-0264Siskiyou County, California

,WMartin W. Mcllroy

TãberSIncê 1954

Mr. Scott Waite, P,E.

Siskiyou County Department of Public Works1312 Fairlane RoadYreka, California 96097

Subject:

MWM/GGWRLFAccompanying: Repofts (4)

Dear Mr. Waite:

Transmitted herewith are four copies of our Foundation Report performed at theabove site. The original transparencies of the "Log of Test Borings" drawings are beingforwarded under separate cover. An electronic version (PDF format) of the "Log of TestBorings" drawíng has been sent to you by e-mail.

Should any questions arise concerning foundation conditions at the site, pleasedo not hesitate to call on us. An opportunity to review and comment on plans andspecifications insofar as they rely on this report is an integral part of ourrecommendatrons.

We appreciate this opportunity to be of service.

Very truly yours,

December 3,20L2

2011-02094IL22-F5:114N;218W

Taber ConsultantsEngineers and Geologists

391.1 W€st Cap¡tol AvenueWesl Sacramento, CA 95691-2116p-r- (916) 371_1690' Síncalgí4 ì.n-r' ^.. ,.oo(707) 575-1568Fax (916) 371-7265www.tåberÇon$u ltanls, com

FOUNDATTON REPORTSchulmeyer Gulch Bridge on Old 99 Highway

Existing Bridge No. 2C-0264Siskiyou CounW, California

County of SiskiyouOwner/Desígn Engineer

2011-020947t22-F5:114N;218W

December 2013

Tebêr Conaultantsêngineers and Gøologísts

:l*i:' ä

TABLE OF CONTENTS Introduction.............................................................................................................. 1

Site Description ......................................................................................................... 2

Project Description .................................................................................................... 3

Geologic Setting ........................................................................................................ 4

Exploration and Testing ............................................................................................. 5

Earth Materials and Conditions ................................................................................... 7

Roadway Fill/Unconsolidated Alluvium ..................................................................... 7 Consolidated Alluvium ............................................................................................ 8

“R”-value .................................................................................................................. 8

Corrosivity Testing .................................................................................................... 8

Groundwater ............................................................................................................ 9

Site Seismic Conditions ............................................................................................ 10

Liquefaction ............................................................................................................ 12

Conclusions ............................................................................................................ 13

Recommendations................................................................................................... 14

Spread Footing Foundations ................................................................................. 14 Pile Foundations .................................................................................................. 15 Soil Pressures ...................................................................................................... 17 Channel Modifications .......................................................................................... 18 Earthwork ........................................................................................................... 19 Temporary Excavations and Slopes ....................................................................... 20 Pavement Design ................................................................................................. 21

Construction Conditions ........................................................................................... 22

Driven Piles ......................................................................................................... 22 Spread Footings .................................................................................................. 23 Structure Removal ............................................................................................... 23

Supplemental Services............................................................................................. 24

LIST OF TABLES Table 1 — Corrosivity Test Results ............................................................................ 9

Table 2 – Spread Footing Data Table ...................................................................... 15

Table 3 – Pile Data Table - Class 140 ...................................................................... 16

Table 4 – Flexible Pavement Sections ...................................................................... 21

Attachments: “General Conditions” “Selected References” Figure-1 “Vicinity Map” “Log of Test Boring Sheet” (11x17”) Figure-2 “ARS Curve” Figure-3 “Boring Log Sheets” (8.5x11”, 2 Sheets) “Boring Legend” Figure-4 “Laboratory Test Results” Figure-5 “Liquefaction Analysis”

2011-0209 FOUNDATION REPORT

Schulmeyer Gulch Bridge on Old 99 Highway Existing Bridge No. 2C-0264 Siskiyou County, California

Introduction

A limited study of subsurface conditions has been completed at the above site

in accordance with the agreement between Siskiyou County Department of Public

Works and Taber Consultants. The purpose of this report is to document subsurface

geotechnical conditions, provide analyses of anticipated site conditions as they

pertain to the project described herein, and to recommend foundation design criteria

for the bridge structure and appurtenant bridge facilities. Limitations of this study

are discussed in the attached “General Conditions.”

This report is intended for use by the project design engineer for design of

proposed improvements. This report is prepared in English units and supersedes our

report titled, “Interim Geotechnical Data,” dated August 14, 2012 and our

“Foundation Report-DRAFT” dated, December 19, 2012.

Elevations and locations presented in this report and its attachments are

based on the existing site features and topography shown on the “Preliminary

Schulmeyer Gulch Bridge Replacement, Located in T44N, R06W, Sec. 18, Final APE

Map,” dated November 22, 2011. An AutoCAD® version of this sheet was provided

to us electronically on May 1, 2012.

2011-0209

Schulmeyer Gulch Bridge on Old 99 Highway / 2

Site Description

Although the existing roadway (Old 99 Highway) generally runs north-south,

it is aligned east-southeast to west-northwest at Schulmeyer Gulch. The asphalt-

paved roadway is two lanes wide with 3 to 6±foot wide gravel shoulders. At

Schulmeyer Gulch, the roadway does not have shoulders or guardrails and the

roadway is carried over the gulch by an existing box culvert.

Roadway grade is at approximately elev. 2755±. Approach fills adjacent to

the box culvert taper away from the culvert at approximately

1.5 horizontal (h):1 vertical (v) slopes and are up to 8±feet in height. The roadway

fill eventually matches the natural grade at about 250±feet west-northwest and

about 140±feet east-southeast away from the bridge. The site coordinates are

approximately: Latitude 41.656153 and Longitude -122.581137.

The original cast-in-place concrete box culvert has three cells aligned

perpendicular to the roadway with its floor resting on native ground. “As-built” plans

for the culvert are not available. According to the Caltrans local bridge inventory, the

box culvert was built in 1925, is structurally deficient, and has a sufficiency rating of

48.7.

At the time of our field visits (November 1, 2011; April 6 and April 30 through

May 4, 2012), 2 to 4 foot rip-rap rocks were observed on the right channel bank

adjacent to the upstream corner of the structure. The rip-rap was apparently placed

for scour protection. Scour at this location is likely due to Schulmeyer Gulch

2011-0209


attacking the right bank prior to being directed 90-degrees left after flowing parallel

with Old 99 Highway on the west side of the roadway.

The floor of the culvert was exposed within the right cell (looking

downstream) and the upstream face of the floor was exposed by scour to about

1.5±feet below the invert. Scour at the downstream face of the culvert was less

than 0.5±feet below the invert. We observed concrete spalling and exposed and

corroded steel reinforcement in one location.

Project Description

The purpose of this project is to replace the existing aging and structurally

deficient culvert. Proposed construction is to remove the existing box culvert and

replace it with a new bridge. The proposed bridge is a 29-ft long and 31-ft wide

cast-in-place reinforced concrete slab bridge based on a loading calculations sheet

dated April 29, 2013 and received electronically from Siskiyou County. Total loading

per support is indicated as 316.3 kips and maximum load per pile is indicated as

106 kips.

It is assumed that abutments will be located at equal distances from the

thread of the channel. Bridge line and grade are expected to match existing

roadway and it is expected that approximately 200-ft of roadway will be replaced/re-

paved as part of the construction work.

The bridge foundation will likely be driven piles (within alluvial materials)

similar to supports (precast concrete piles) for bridges on Interstate-5 (I-5)

2011-0209


downstream. For planning and preliminary design purposes, both driven piles and

spread footing foundations are being considered by the County.

It is understood that the Old 99 Highway will be closed during construction

with traffic diverted to Interstate-5 and other routes. Channel modifications are not

indicated on schematic plans.

Geologic Setting

Within project limits, published geologic mapping (Hotz 1974, 1977, and

1978, and Strand 1963) show the project area as underlain by Quaternary Alluvium

with the hills on either side of I-5 shown mapped as Ordivician-Silurian Duzel

Formation and Antelope Mountain Quartzite. The Duzel Formation is a marine

deposit consisting of phyllite, graywacke, chert and limestone. Alluvial materials in

the channel consisted of sand, gravel and cobbles.

Recent Alluvium is described as unconsolidated stream and basin deposits,

clay- to boulder-size. Older Alluvium is indicated to underlie the Recent Alluvium,

and is described as consisting of poorly-consolidated to fairly well compacted sand,

silt, and clay containing scattered rounded pebbles.

The closest Quaternary-active fault (undifferentiated activity within the past

1.6 million years) is the Yellow Butte Fault, located about 14±miles east of the site.

The late Quaternary-active (within past 700,000 years) Mt. Hebron fault zone and

the Holocene-active (within past 11,700 years) Cedar Mountain fault zone are

located about 30±miles east of the site.

2011-0209


There are several pre-Quaternary faults mapped within about 10±miles of the

site with the closest fault approximately 0.5±miles away; pre-Quaternary faults do

not have recognized activity within the past 1.6 million years.

Exploration and Testing

Office study included review of published geologic mapping, online aerial

photos, and the above-noted APE map. Field work included site

review/reconnaissance along the proposed bridge and roadway alignment, and

measured stream profiles along the upstream and downstream faces of the bridge.

Information on the nature and distribution of subsurface materials and

conditions was obtained by means of four sampled test borings drilled to depths

ranging from 7-ft to 67±ft (lowest elev. 2688±). The borings were drilled using a

CME-75 truck mounted rig equipped with a calibrated automatic hammer. The

hammer energy ratio (ERi) for the hammer used is ERi=71% (last calibrated

November 28, 2011).

Borings drilled for the bridge foundations were advanced using 6-inch and 4-

inch solid flight auger and then advanced with 3.7-inch wireline mud rotary

equipment to final depth. Roadway borings were drilled with solid flight auger to

total depth.

Relatively undisturbed samples were recovered from the borings by means of

1.4-in inside diameter (I.D.) "Standard Penetration Test" (SPT, ASTM D1586)

sampler advanced with standard 140-lb calibrated automatic hammer with a 30-in

2011-0209


drop to provide a field estimate of soils consistency. A 2.5-in I.D. split-barrel sampler

was also used, and was driven in the same manner as the SPT sampler. Sampler

penetration resistance was recorded and can be correlated to soils strength and

bearing characteristics. Samplers were driven with liners.

Bulk bag samples were taken from Borings-1, -2, and -3. Borings-1 and -4

were drilled for the bridge foundations and Borings-2 and -3 were drilled for the

roadway. Samples were taken for material classification and evaluation, direct shear

strength, corrosivity, and “R”-value testing. The samples were taken to our

laboratory for testing.

The borings were logged and earth materials field-classified by a registered

geologist as to consistency, color, gradation, and texture on the bases of sampler

penetration resistance, examination of samples, and observation of auger/drill

cuttings. Groundwater was measured where encountered in the borings and within

the channel during drilling operations. Each test boring was backfilled with cement

grout after completion.

Field exploration was conducted on April 30 and May 1, 2012 for the bridge

and roadway geotechnical studies. Further environmental field work was conducted

through May 4, 2012 after completion of the geotechnical field work. Results of

environmental studies are reported under separate cover. Boring elevations were

referenced to Siskiyou County Control Point 23 (CP 23), elevation 2756.70, located

32±feet right at STA 3+71±.

2011-0209


Locations, details of borings and results of tests are included within the

attached figures and on the “Log of Test Borings” drawings. Glen G. Wade, P.G.,

was the field geologist for this study.

Earth Materials and Conditions

Earth materials encountered in borings completed for this study are divided

into two general units considered significant to this project: roadway

fill/unconsolidated alluvial materials and consolidated alluvium.

Roadway Fill/Unconsolidated Alluvium

Roadway fill was found in all borings from the bottom of the pavement to

8±feet below the ground surface. This unit generally consists of very stiff sandy

silt/clay with gravel or compact silty sand with gravel. Sand and gravel content

varied depending on the boring location. Soft/loose fill was found below 4.5-ft

depth in the roadway embankment.

Very soft to stiff sandy clay with gravel or loose to dense clayey sand with

gravel was encountered below the roadway fill. These materials extended to the

bottom of Borings-2 and -3, and to about elev. 2735± and 2733± in Boring-1 and -

4, respectively. Materials in this unit are considered generally susceptible to scour

and compressible under foundation loading and/or during secondary seismic effects.

2011-0209


Consolidated Alluvium

Consolidated older alluvial materials were encountered below the

unconsolidated recent alluvial materials at about elev. 2735± and 2733± in Boring-1

and -4, respectively. This unit consists of compact to very dense silty clayey sand

with gravel to clayey gravel with sand. These materials extended to the bottom of

Borings-1 and -4 (elev. 2697.8± and 2687.9±, respectively).

A soft clay layer that is likely discontinuous is present in Boring-4 at elevation

2715. This layer is approximately 3 to 4-ft thick. This soft layer was not present in

Boring-1.

Materials in this unit are considered capable of supporting heavy

concentrated foundation loading.

“R”-value

One “R”-value test was performed on materials from the existing roadway

embankment. It is expected that these materials will be re-used as part of the new

embankment. The test was performed on Bag B from Boring-2. The test indicates an

“R”-value of “R”=77.

Corrosivity Testing

Corrosivity testing was performed on soil samples recovered from Boring-4.

Soil samples were taken from driven split-barrel samplers. Samples 2 and 3 (depths

of 7.5-9.5±feet and 15-17±feet) were combined for one test, while samples 7 and 8

(depths of 35-37±feet and 40-42±feet) were combined for the second test.

2011-0209


Table 1 — Corrosivity Test Results

Boring No. / Sample No. pH Minimum Resistivity (ohm-cm)

Chlorides (ppm)

Sulfates (ppm)

4 / 2 and 3 (combined) 7.70 4290 6.3 34.3

4 / 7 and 8 (combined) 7.34 3480 10.8 48.5

The test results indicate a “non-corrosive” soils environment. Results of soils

corrosivity testing is shown in Figure-4, attached.

Groundwater

The channel was dry during our November 1, 2011 site visit. The channel

water surface was measured during our site visits on April 6, 2012 and between

April 30 to May 4, 2012. The “first-encountered” groundwater levels within the

boreholes (Borings-1, -2 and -4) measured between 2747 and 2748 during drilling

operations. On April 6, 2012, groundwater was measured at elev. 2747± within the

channel. Groundwater was not encountered in Boring-3 as it was likely completed

just above groundwater levels within the roadway embankment at the time of field

exploration. Seasonal groundwater may be encountered at higher or lower

elevations throughout the year depending on seasonal conditions.

2011-0209


Site Seismic Conditions

The following seismic analysis and data is intended for design of the

proposed Schulmeyer Gulch Bridge at Old 99 Highway, Siskiyou County, California.

The Caltrans ARS Online tool deterministic spectrum for the site is based on

the Minimum Deterministic Spectrum for California. The “controlling” fault for the

site is the Cedar Mountain Fault System (Ike’s Mountain section), Maximum

Magnitude 7.1, located about 30±miles northeast of the site.

The Design Envelope ARS Curve (see Figure-2) is the 5% in 50 years USGS

deaggregation data (the Caltrans-recommended probabilistic data for sites with

Vs30≤300 meters per second) for periods of 0-2 second. The Caltrans ARS Online

Probabilistic Curve (USGS 5% in 50 years hazard) is the basis for the Design

Envelope Curve for periods greater than 2 seconds.

Based on available data, the site can be conservatively assigned a soils profile

Type-D (per Table B.12, Caltrans “Seismic Design Criteria” (SDC) Appendix B Rev.

10/2010).

The Design Envelope ARS Curve for the proposed bridge location is based on

data from Boring-4, located 7±feet right at STA 4+98. Coordinates and estimated

shear wave velocity for the calculations included:

Latitude: 41.65614; Longitude: -122.58107; and Vs30: 291 meters per second (955 feet per second).

2011-0209


The Design Envelope ARS Curve has a peak ground acceleration of 0.27 g.

Caltrans structure design practice requires an increase in the spectral

accelerations due to fault proximity (within 25 km) and when projects are located

over a deep sedimentary basin (basin factor). These factors do not apply to this site.

It should be noted that per Caltrans SDC §2.1.5, if the bridge meets the

criteria of an Ordinary Standard Bridge as defined in Caltrans SDC §1.1, a reduction

factor could be applied to the 5% damped response spectrum used to calculate

displacement demand.

Based on the above information, structure design is recommended to be

based on the following SDC parameters:

Soil Type D;

Controlling Spectra, (T=period):

o 0<T<2 seconds, 5% in 50 years USGS deaggregation data

o T>2 seconds, Caltrans Probabilistic Design Spectra; and

Peak Bedrock Acceleration: 0.27g.

A Design Envelope ARS Curve developed from the Caltrans ARS Online tool

and from the USGS seismic hazard website is presented in Figure-2.

No fault traces are mapped passing through the project site on published

geologic mapping or on the Caltrans ARS online map. The site is also not in an

“Alquist-Priolo Earthquake Fault Zone” for fault-rupture hazard. No evidence of fault

rupture was noted from geologic reconnaissance. On these bases, the potential for

ground rupture is considered low.

2011-0209


Liquefaction

A liquefaction analysis was completed for Boring-1 at Abutment-1 using

laboratory test and boring data correlated from the test borings. Percentage of fines

and D50 input parameters were estimated from the soils descriptions on the “Log of

Test Boring” sheets and, where appropriate, taken from laboratory test results.

Where classification tests were not available for soil units, fines content was

estimated based on the soil descriptions. Liquefaction and settlement were analyzed

using LiquefyPro ver. 5.

Results of analysis indicate a potential for liquefaction within the loose clayey

fine to coarse sand layers encountered in the borehole and previously described.

The sand layer appears marginally liquefiable based on the factors of safety

calculated. Increases to the estimated fines content by only a few percentages,

indicate that this layer would not be considered liquefiable.

Cyclic softening in the very soft and stiff lean clay above the sand may also

occur. Total settlement from liquefaction/cyclic softening is calculated as

approximately 0.7 inches within the upper 12-ft of the soil column.

Liquefaction and secondary seismic settlement are only realized during a

seismic event and are not expected to affect normal bridge operations and service

limits. Potential settlement from secondary seismic affects appears to be low and

likely less than 1-inch. For this simple, single- span bridge, it is expected that

settlement on the order of 1-inch could be tolerated with differential settlements

2011-0209


less than the total realized settlement and likely limited to ½-inch or less. Should

there be important structural and/or economic considerations associated with more

closely defining the above values or other site-seismicity characteristics, further

study would be required.

Conclusions

The site appears adequately stable and capable of supporting the proposed

bridge and embankments.

At the request of the County, options and recommendations for spread

footing foundations and driven piles are provided.

Adequate soil support is available at the site and conditions are suitable for

driven pre-cast concrete piling for the bridge (including wingwall wall structures)

and such support is recommended. Recommendations are provided below for

Caltrans Standard Class 140 driven displacement piling.

Driven steel H-piling or pipe piling is also an acceptable foundation type at

the bridge supports. The presence of groundwater and caving soil precludes the use

of Caltrans “Standard” 16-inch diameter cast-in-drilled-hole (CIDH) piling. However,

24-inch and larger diameter CIDH piles are technically feasible but will require

tremie concrete pour and wet installation specifications.

Spread footing foundations also appear feasible for foundation support if

certain considerations are made and risks are understood. Concerns for spread

2011-0209


footing foundations include: potential excavations below groundwater, limited

available bearing capacity and scour susceptibility.

Recommendations

Spread Footing Foundations

Spread footing support is available, but requires consideration of potential

scour and changes in channel grade. For the indicated bridge layout, such a footing

would need to be below existing channel grade possibly requiring shoring,

dewatering and tremie pour or seal course. Neglecting scour effects, a maximum

spread footing elevation of elev. 2744 is required. Scour depths may affect final

footing bottom depths and also may require riprap protection to help limit scour at

the abutments.

For planning purposes, spread footings could be established on native

materials below the existing roadway embankment to the elevation previously

indicated. Preliminary allowable bearing capacity of 2 ksf would appear appropriate.

Footings are assumed to be at least as long as the bridge structure is wide and at

least 10 ft in width. Spread footing bottoms should be established at least 3-ft below

grade or to elev. 2744 (whichever is deeper) in intact native materials for the above

allowable gross bearing capacity to be used. The designer should determine the

actual footing widths. The abutment footings should be set back a minimum of 5 ft

from the proposed channel finished slope face.

2011-0209


Based on encountered earth materials and conditions, we have developed the

following table:

Table 2 – Spread Footing Data Table

Support Location

Footing Size

Bottom of

Footing

Elevation (ft)

Minimum

Footing Embedment

(ft)

Working Stress Design (LRFD Service-I Limit State Load

Combination) Load Resistance Factor Design

Width Length

Permissible

Gross Contact

Stress

(ksf)

Allowable

Gross Bearing

Capacity

(ksf)

Service Strength Extreme

(ft) (ft)

Permissible

Net Contact

Stress (ksf)

Factored

Gross Nominal

Bearing

Resistance (ksf)

Factored

Gross Nominal

Bearing

Resistance (ksf)

(φ=0.45) (φ=1.0)

Abut-1 10 30.6 2744

3 2 2

N/A N/A N/A

Abut-2 10 30.6 2744

3 2 2

N/A N/A N/A

Settlement on the order of 1-inch from liquefaction/cyclic softening within the

loose sand and soft layers may occur. The thicknesses of the sand layer from one

support to the other differ and settlements from one support to the other could

vary. Differential settlement along the footing length may also be realized but should

be less than the total estimated settlement.

Pile Foundations

Driven pile foundations are feasible and recommended. Piles are assumed

driven from elev. 2750 (assumed pile cut-off elevation). Borings did not encounter

boulders or cobbles, but, the presence of cobbles within this interval cannot be

2011-0209


precluded based on the drill action recorded in the field and the descriptions in

published mapping. Overhead clearances appear suitable for pile driving.

Caltrans Standard Class 140 pre-cast concrete piles are recommended for the

bridge foundations. Pile capacity calculations and specified tip elevations neglected

contributions from the upper 9±ft of the soil profile below the cutoff elevation.

Assuming a “free-head” condition and applying methods outlined in ATC-32

and Naval Facilities Design Manual 7.2 (with coefficient of variation of subgrade

modulus “f” taken as 20 pci for intact native soft-stiff clay or semi-compact sand

below elev. 2740±), lateral stiffness of 12 inch square concrete piles at abutments is

estimated as about 10 kips/inch and “ultimate” lateral capacity as 20 kips.

A “Pile Data Table” reflecting the above recommendations is as follows. This

office should be consulted in the event that changes in pile type, cut-off elevation

and/or loading are required or if tensile and/or lateral loads need additional

consideration.

Table 3 – Pile Data Table - Class 140

Location Pile Type

Cut-

off Elev.

(ft)

LRFD Service-I

Limit State Load per support (kips)

LRFD Service-I

Limit State Total Load per

pile (compression)

(kips)

Nominal Resistance

(kips)

Design

Tip Elev.

(ft)

Specified

Tip Elev.

(ft)

Nominal Driving

Resistance Required

(kips) Total Permanent

Abut-1

12” Square concrete

(Class 140) 2750 316.3 N/A* 106 215

2700 (1);

2720 (3) 2700 370

Abut-3

12” Square concrete

(Class 140) 2750 316.3 N/A* 106 215

2700 (1);

2720 (3) 2700 370 1) Design tip elevations are controlled by: (1) Compression; (2) Tension; (3) Lateral Load 2) Piles are assumed driven from an assumed cutoff elevation of elev. 2750. 3) Pile Loads are assumed design loads using Caltrans Standard Plans values. 4) *Service Limit-I Limit State Loads have not been provided

2011-0209


All piles should be specified to penetrate to or below Specified Tip Elevation

and should have full design bearing per the Gates Formula at final penetration. For

implementation of the Gates Formula on this local agency project, an “ultimate”

driving resistance value of 370 kips should be used for the given design loads for

Class 140 piles. This driving resistance value follows recommendations by FHWA for

implementation of the Gates Formula for driving resistance and has been indicated

by FHWA literature to provide a bearing capacity more consistent with design

service loading conditions and is appropriate for local County bridges where dynamic

pile analysis and load tests are typically not used.

Assuming adequate materials and workmanship, piling meeting effective

“refusal” within 5 ft above specified tip elevation may be considered acceptable

without specific review by this office. For this purpose, “refusal” may be considered

as at least twice required formula bearing in the last foot or three times the required

bearing within the last 3-inches of driving. Possible difficult driving conditions may

be encountered (but are not anticipated) at higher elevations above specified tip

elevations; pre-drilling may be an option for use as a driving aid only after

consultation with this office.

Soil Pressures

With the use of excavation/backfill details per Caltrans “Standard Plans,”

active soil pressures on abutment walls may be calculated on the basis of an

2011-0209


equivalent fluid pressure of 36 pcf. Passive soil pressures may be calculated on the

basis of an equivalent fluid pressure of 400 pcf.

Seismic loading will apply additional soil pressure to abutment/retaining walls.

Incremental lateral soil pressure due to seismic loading may be calculated on the

basis of an equivalent fluid pressure of 11 pcf with the resultant load acting at 0.6

times the wall height above the base of the wall. The equivalent fluid pressure will

vary depending on actual wall configuration and slope condition and should be

reviewed during design. For seismic conditions, passive soil resistance of up to 5.0

ksf is available for resistance to seismic loading - to be reduced for effective wall

height less than 5.5 ft in accordance with Caltrans “Seismic Design Criteria” (v.1.6).

Channel Modifications

It is recommended that slopes be configured at 1.5h:1v at the steepest when

re-grading the channel. Flatter configurations would also be acceptable and final

slope configuration will likely be dependent on structure to slope geometry. Existing

embankment soils are considered susceptible to scour. We anticipate that adequate

scour protection will be provided or potential scour conditions mitigated by some

other countermeasure. The abutments should be set back a minimum of 5 ft from

the proposed channel slope face.

Preliminary calculations indicate that stiff near-surface soils should not liquefy

in a seismic event. However, it does appear that minor lateral movement upon the

potentially liquefiable layer between elev. 2750 and 2746 cannot be precluded and

2011-0209


may potentially be susceptible to some minor slope failure (within the lower 5 ft of

the channel) in a major seismic event. Scour protection may help reduce the

susceptibility of the abutment slope to lateral displacement.

On the downstream side of the culvert, some minor scour may have occurred

as water flowed over the slab. Re-grading in this area of the channel may require

placement of fill to establish finished grades as indicated on the plans. However, the

actual extent of possible scour has not been determined; during construction it

should be determined whether fill will be needed to fill in scour areas on the

downstream side of the culvert.

Earthwork

All earthwork should be performed in accordance with Caltrans Standard

Specifications supplemented by the recommendations below.

The area to be graded should be stripped of all debris, vegetation, and other

organic material. Where woody vegetation is removed, all substantial roots should

be excavated and removed. Debris, organic material, and otherwise unsuitable

materials should be disposed to an approved location.

The surfaces to receive fill should be scarified to 6-inch depth, moisture

conditioned to at least optimum-moisture content, and compacted to at least 90%

relative compaction (per CTM 216). Inability to achieve the required compaction on

the scarified materials may be used as a field criterion to identify areas requiring

additional removal and/or compaction (locally soft / loose soils).

2011-0209


Embankment fill slopes of 2h:1v or flatter are considered acceptable. Where

new fill is to be placed onto existing fill or natural slopes exceeding 5h:1v, it should

be placed on discrete benches cut fully into the slope and below any loose/soft or

otherwise unsuitable materials (per Section 19 of Caltrans “Standard

Specifications”). These recommendations can be modified by the Registered

Engineer in charge of the project based on soil exposures and grading operations

during earthwork activities.

On-site soils (less debris or organic material and any boulders) are considered

generally acceptable for use as compacted embankment fill and, except as described

below, should be placed to at least 90% relative compaction at or above optimum

moisture per CTM 216. Relative compaction of at least 95% (CTM 216) should be

achieved on all fill within 150 ft of the bridge and within 30 inches of finished grade

for pavement sections. Imported embankment fill should be approved by the

engineer and have "low" expansion potential (Expansion Index less than 25 or

Plasticity Index less than 20).

Temporary Excavations and Slopes

Temporary groundwater pumping is expected to control groundwater in

excavations. Temporary construction backslopes should be reviewed during

construction in evaluation of stability and for possible supplemental support (e.g.,

local shoring in areas of soft/weak materials). It is expected that construction back

slopes should be stable at configurations of 2h:1v or flatter. Temporary excavations

2011-0209


of 1h:1v are likely acceptable, but may require shoring to conform to CalOSHA

standards. Shoring and site safety are the responsibility of the contractor.

Pavement Design

Design of new pavement based on basement “R”=50 is considered

appropriate for this project. This assumes re-use and re-compaction of the existing

embankment materials. Pavement section design is based on Traffic Index (TI) and

“R”-Value, but should also reflect local experience and practice, depth and nature of

subgrade preparation, and acceptable level of maintenance.

Preliminary flexible pavement sections calculated in accordance with Caltrans

design methods (Highway Design Manual, Chapter 600) at design “R”=50 and for

TI=9.0 through 13.0 inclusive are shown in the following table.

Table 4 – Flexible Pavement Sections

AB AS Structural Section

Asphalt Class 2 Class 3 Thickness

(ft) (ft) (ft) (ft)

0.45 1.00 0.35 1.80

0.50 1.50 -- 2.00

0.50 1.10 0.45 2.05

0.55 1.70 -- 2.25

0.55 1.25 0.50 2.30

0.60 1.85 -- 2.45

0.60 1.35 0.55 2.50

0.65 2.05 -- 2.70

0.65 1.45 0.65 2.75

T.I.

Preliminary Flexible Pavement Sections

"R"=20

12.0

9.0

10.0

11.0

13.0

0.45 1.30 -- 1.75

2011-0209


Pavement sections shown in the table above incorporates a 0.20-ft gravel

equivalent safety factor. Other flexible pavement structural sections for traffic index

values other than those shown can be provided, if desired.

Design by the Caltrans method presumes materials and construction in

accordance with Caltrans “Standard Specifications,” including 95% relative

compaction (CTM 216) on all materials within 30-inches of finished grade. Inability

to achieve the required compaction on the scarified materials may be used as a field

criterion to identify areas requiring additional removal and/or re-compaction.

The subgrade soils should be field reviewed with respect to uniformity and

suitability by the soils engineer. Any unsuitable material, including clay and loose or

disturbed soils, should be removed to full depth and replaced with granular native

soil or Class 2 aggregate base compacted to at least 90% relative compaction (CTM

216). Native granular soils – less debris, organic material and particles over 4-inches

greatest dimension – are considered suitable for use as compacted fill.

The above pavement design assumes that free water will be absent from the

structural section. Suitable surface drainage is of particular importance to limit

subgrade saturation and excess free water.

Construction Conditions

Driven Piles

Extensive free groundwater is not expected within the depth of abutment

excavations if constructed during the dry season. This assumes a pile cap for driven

2011-0209


piles at elev. 2750. Seasonally, some seepage may be present which is expected to

be controllable by means of pumping within the abutment areas.

This office should be contacted in the event the piles do not meet bearing

criteria or if piles are driving harder before reaching specified tip elevation.

Spread Footings

For spread footing construction on native materials, groundwater may be

present. It is expected that pumping should help control seepage. However, more

granular layers within the excavation may be capable of transmitting larger volumes

of water into the excavation and could be susceptible to collapse (depending on the

slope geometry) and require shoring. Sandbags or other techniques could be

considered within the excavation to help slow seepage transmission and help

facilitate pumping.

Spread footings should be poured neat without forming against intact native

materials as affirmed by this office or the resident engineer in charge of the project.

Footing construction requires concrete that is poured neat without forming against

undisturbed rock. If excavations are unable to be dewatered, the use of a tremie

seal course can be considered for spread footing foundations.

Structure Removal

The entire existing bridge and appurtenant structures will be removed as part

of this project and disturbance to channel slopes and soil beneath support areas is

expected. The depth of the box culvert concrete slab and cut-off walls within the

2011-0209


channel is unknown; depending on thickness of the slab, channel disturbance may

be below the proposed bottom channel finished grade and could affect final footing

elevations. Reprocessing of the channel bottom soils and banks can be expected as

a result of structure removal.

Taber Consultants personnel should be on-site to observe and confirm the

exposed surfaces that will be re-graded and re-processed after removal of the

structures. This will allow us to confirm anticipated subgrade/native soil conditions

are as expected and also to quickly provide further recommendations if unexpected

or emergent conditions are discovered during construction.

Borings did not encounter boulders or cobbles, but, the presence of cobbles

within this interval cannot be precluded based on the drill action recorded in the

field and the descriptions in published mapping.

Supplemental Services

Within our profession it is recognized that the risks of design, construction,

and maintenance-related problems associated with civil engineering works are

typically higher and result in increased overall project cost when the geotechnical

engineer of record is not retained to provide supplemental services. For this project,

Taber Consultants should provide the following supplemental geotechnical services:

review and provide written comments on the final plans and specifications, insofar as they rely upon this report, prior to construction bidding to verify consistency with the recommendations contained herein; and,

TaberSlnce 1954

2011-0209

. Review/observe footing foundation excavations during construction to confirmbearing materials in order to provide additional or alternate recommendationsif necessary.

Should there be significant change in the project or should soils conditions

different from those described in this repoft be encountered during construction,

this office should be contacted/notified for evaluation and supplemental

recommendation as necessary or appropriate.

Taber Consultants cannot be responsible for interpretations made by others

regarding our repoft and the recommendations contained herein. If construction

observation is peformed by others, they should review this repoft and either accept

the conclusions and recommendations herein as their own or provide alternative

recommendations,

Martin W. Mcllroyc,E.G, 2322, P,E. 78846

TABER CONSULTANTS

December 3,2013


2011-0209 GENERAL CONDITIONS

The conclusions and recommendations of this study are professional opinion based upon the indicated project criteria and the limited data described herein. It is recognized there is potential for sufficient variation in subsurface conditions that modification of conclusions and recommendations might emerge from further, more detailed study. This report is intended only for the purpose, site location and project description indicated and assumes design and construction in accordance with Caltrans practice. As changes in appropriate standards, site conditions and technical knowledge cannot be adequately predicted, review of recommendations by this office for use after a period of two years is a condition of this report. A review by this office of any foundation and/or grading plans and specifications or other work product insofar as they rely upon or implement the content of this report, together with the opportunity to make supplemental recommendations as indicated therefrom is considered an integral part of this study and a condition of recommendations. Subsequently defined construction observation procedures and/or agencies are an element of work that may affect supplementary recommendations. Should there be significant change in the project, or should earth materials or conditions different from those described in this report be encountered during construction, this office should be notified for evaluation and supplemental recommendations as necessary or appropriate. Opinions and recommendations apply to current site conditions and those reasonably foreseeable for the described development--which includes appropriate operation and maintenance thereof. They cannot apply to site changes occurring, made, or induced, of which this office is not aware and has not had opportunity to evaluate.

The scope of this study specifically excluded sampling and/or testing for, or evaluation of the occurrence and distribution of, hazardous substances. No opinion is intended regarding the presence or distribution of any hazardous substances at this or nearby sites.

2011-0209 SELECTED REFERENCES

1. Mack, Seymour, 1960, “Geology and Ground-water Features of Shasta Valley,

Siskiyou County,” California: U.S. Geological Survey, Water-Supply Paper 1484, scale 1:62500.

2. Hotz, P.E., 1974, “Preliminary Geologic Map of the Yreka Quadrangle, California:” U.S. Geological Survey, Miscellaneous Field Studies Map MF-568, scale 1:62500.

3. Hotz, P.E., 1977, “Geology of the Yreka quadrangle, Siskiyou County, California:” U.S. Geological Survey, Bulletin 1436, scale 1:62500.

4. Hotz, P.E., 1978, “Geologic Map of the Yreka Quadrangle and Parts of the Fort Jones, Etna, and China Mountain quadrangles, California:” U.S. Geological Survey, Open-File Report OF-78-12, scale 1:62500.

5. Strand, R.G., 1987, “Geologic Map of California: Weed Sheet:” California Division of Mines and Geology, scale 1:250000.

6. Miller, C.D., 1981, Potential Hazards from Future Eruptions in the Vicinity of Mount Shasta Volcano, northern California: U.S. Geological Survey, Bulletin 1503, scale 1:62500.

Copyright (C) 1997, Maptech, Inc.

Taber ConsultantsEngineers and Geologists3911 West Capitol AvenueWest Sacramento, CA 95691-2116916.371.1690 Fax 916.371.7265www.taberconsultants.com

Siskiyou County Department of Public Works

2011-0209 Figure–1

Vicinity Map

Schulmeyer Gulch Bridge at Old 99 HighwaySiskiyou County, California N

1:24000

USGS “Montague, CA” Quadrangle7.5 Minute Series (Topographic),Dated 1984.

SITE

20000

To Yreka

To Grenada

Interstate 5

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TABER CONSULTANTS3911 Wost Cepitol AvenueWest Secrarnento, CA 95691-21 16

e.\ I

2770

2760

2790 ^***"*tmi'n'm SrûO od fiAçL ndlt to tL ([l)

"''[.f fil'å",# *:-"ffi *"i.i iuJ:",

2740 (bbmretl od loñ dlo# bor UE ft. to cmSO iS ft. to c@ fiAW. it, úgdû, l--YSIT od UY lr-

2730h¡ rJd bor Jö dd db motüh! 9LÍ ilEfü. lo @- ilD

'¡ü ft. to m CRA\€L ñd. mrtd

Cmret to dr! dd )dldú dd*Þoñ ar UEY Sm dth m^É rl

NOrES:l. Flcld c{olsificot¡on of soils wos ¡n qçctdoncc with ASnl D

2,+88-06'D€scriptiff qnd ldntificotìon of Soils (VÌsuol-MonuqlProcedure)".

2. Stqndord Pen€trotlon t€sta wtrs psrfomsd in occsdonce withAS'fi¡ D l5E6-99 us¡ng o hommü op€roted with on outomqteddrop systo, Drill rods wcr€ 1S/E-inch diomctq'A'-rods;sqmplã wos drívrn with brols linqs.

J. '2.5 inch sompl€r'; 10=2.5 inch, OD=2.9 ¡nch; oriwn in somemonn€r os sPT ('1.4 ínch') sompltr.

4. fhe l€ngth of eqch sompl6d int€rvol is shown grophicolly q thebq¡ng log. llho{€ numb€r blow cilnts ("N') represøt the'etqndqrd pcnatrotìon rcsistonce' ínterwl in qccordq¡co w¡thASÌf¡ 01566-99. llhrr! l.!s thon 1 foot of p6otrqt¡ø lsqchi€wd, thq blow c@nt rhown is for thqt frqct¡ø af the'stondord p€netrotion ¡esìstonce' intervol octuolly penstroted.

5. lthere indicot€d by on qsterisk (r) the number of blows shornis for only thqt froction of the initlol 0.5 ft. 'seoting driw'ínttrvol pq€trqted.

6. SPT hommer 6dgy meqsu¡flcnts were not token. Recenthommer enqrgy rqt¡o (ERi) mGosur€ments ¡ndicot€ qn ERi =71X.

7. Conslst€ncy of soils shown ìn ( ) whøe €stimoted,

4ZZ f\ 6. Groundwots wrfoce (GllS) el€votlons ln th€ borings ¡ndicot€d¿I ( V on th€ Log of Test B'orin{ She€ts r€|!€ct th€ fluid-lev€l in the

bor¡ngs on th€ spEc¡f¡€d dot€.

27609. Groundwottr wrfoc€ elevotions ore subþct to seosonol

lluctuotims ond mqy occur qt hlgher or lower devotlonsdepending on the conditiøs qt ony porticulqr tíme.

10. Electron¡c medíq for plqn view provlded by Siek¡)ou County DPlvon Mqy 1, 2012

11. the "Log of Tcst Borings'drowing ¡! included with plons ¡nqccordonc€ with S€ct¡on 2-1.05 of Coltrons 'StondordSpecfrco0on9.

12. Logs (6.5x11'sheets) for Borings 2 qnd 3 ore provid€d in theFoundot¡on Report.

2740

2730

2720 =

B-1

PLAN1"=20'

A.v. 2717.+3-1-7012

A/C ø Ag.gd. &r ü¡(vry rtlfilcqæt) ilÐY UY dth'æÀv+t'.ú* (¡i 2750($ft/ry -ftì d hú ilY dh sp

dd tu CR^!ll- mdtt to f,t, (ñl)Cqoct Ëdn dú od dd h UEY ft. to cffi

SrúO rlü h. b ffi eR^\tr- ffitd, ñod, (h-F^ ñ{)

(Stll0 llgnt æy tr UY Jh m. to ts6sN od GnAEL md.t

hret dda r.ddldr od ffi hom ctAìEY ft. towr SÆ0 lh ft. to cm GAEI- cñút 4 md.t

Lod t{ol* dh qd ffi Hoú CUì€Y fr. toúr ilo iü fr. to c@ mEL d

(Smb@@o to hr, Éoló du {6m WO ff fr. to cm eAE. Woü ilEY ñ. toY cmrté mdd to mt

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ELEVATION REFERENCE:

@"tocotedJ2.15+71 , älevotîon 2756.70 per Siskiyouof Public Works.

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SCHULMEYER GULCH BRIDGE AT OLD 99 HIGHWAYGLEN G. WADE, P.G.FIELO INlES¡CATOR

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SISKIYIU CIUNTYDTPARII.ITNT [F PUBLIC VIRKS LOG OF TEST BORINGS

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Caltrans Design ARS Envelope Curve Schulmeyer Gulch Bridge at Old 99 Highway Siskiyou County, California

2011-0209 December 2013

Figure-2

VS30: 291 m/s (955 //s) Peak Ground Accelera>on: 0.27 g La>tude: 41.65614 Longitude: -‐122.58107 Site Class: D Nearest Fault: Cedar Mountain Fault System

(Ike’s Mountain sec>on) Maximum Magnitude: 7.1 Controlling Spectrum: 0 < T < 2 seconds

2008 USGS Deaggregated Spectrum

T > 2 seconds Caltrans ARS Online Probabilis>c Spectrum

Period (sec)

Spect.Accel.

0 0.270.1 0.450.2 0.630.3 0.640.5 0.561 0.342 0.193 0.114 0.085 0.05

2.0

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Asphalt concrete over 1.5-ft of Aggregate Base(compact) SILTY SANDY GRAVEL, (fill), dry to moist

(Compact) SILTY SAND with GRAVEL, (fill) dry to moist

Dense, yellowish and dark reddish brown with grayCLAYEY SAND with GRAVEL, moist to wet

Bottom of hole at 7.0 feet.

Groundwater encountered at 6.9-ft depth on April 30,2012.

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FIGURE 3

STATION: 8 ft left, STA 6+37SURFACE ELEVATION: 2754.6

PAGE 1 OF 2

Job No. 2011-0209TEST BORING LOG

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THE BORING LOGS SHOW SUBSURFACE CONDITIONS AT THE DATES ANDLOCATIONS INDICATED AND IT IS NOT WARRANTED THAT THEY ARE REPRE-SENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.

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Stiff, dark brown and brown mottled CLAY with traceSAND, (fill), moist

Bottom of hole at 7.0 feet.

Groundwater was not encountered within the borehole,April 30, 2012.

2.8 114

CLBag

712

FIGURE 3

STATION: 6.5 ft right, STA 3+75SURFACE ELEVATION: 2755.4

PAGE 2 OF 2

Job No. 2011-0209TEST BORING LOG

TYPE: 6-IN SFA BORING NO. 3

LOG

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DS

OIL

CLA

SS

IFIC

AT

ION

LOGGED BY: GGW

(%)

DATE: 04-30-2012

THE BORING LOGS SHOW SUBSURFACE CONDITIONS AT THE DATES ANDLOCATIONS INDICATED AND IT IS NOT WARRANTED THAT THEY ARE REPRE-SENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.

SA

MP

LE N

o.

DE

PT

H

IN F

EE

T

BLO

WS

/FO

OT

350

ft-lb

5

10

15

20

25

30

35

40

SA

MP

LE S

IZE

(inch

es)

DR

Y D

EN

SIT

Y(lb

s/cu

. ft.)

Moi

stur

e

OT

HE

R T

ES

TS

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

0.0010.010.1110100

D30 = 0.565 D10 =

Cc = Cu =

10024 16 301 20010

GRAIN SIZE IN MILLIMETERS

Sieve Size Percent Finer

coarse fine finemedium

50HYDROMETERU.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS

3 4 20 406 60

GRAIN SIZE DISTRIBUTION

FIGURE-4

1.5

% FINES

3/4

0.0

Material Description

3/8

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse

16.5

% Clay% Silt

12.5 29.3 14.214.7

Atterberg Limits

% SAND% COBBLES

Coefficients

Depth: 20.0ft

D100 = 37.5 D60 = 5.078 D50 = 2.93

SILTY, CLAYEY SAND with GRAVEL(SC-SM)

PL = 15

1 1/2"1"

3/4"1/2"3/8"#4#10#20#40#100#200

Project No.2011-0209

100.096.487.583.376.758.243.534.227.117.714.2

Boring/Sample: B-1/6 and 7

Siskiyou County DPWSchulmeyer Gulch Bridge at Old 99 Highway

Siskiyou County, California

LL = 22 PI = 7

% GRAVEL41.8

12.8

14.244.0

Since 1954


0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

0.0010.010.1110100

D30 = 0.257 D10 =

Cc = Cu =

10024 16 301 20010





3 4 20 406 60


FIGURE-4

1.5

% FINES

3/4

0.0


3/8

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse

19.2

% Clay% Silt

11.5 17.3 16.714.3

Atterberg Limits

% SAND% COBBLES

Coefficients

Depth: 20.0ft

D100 = 37.5 D60 = 2.411 D50 = 1.105

CLAYEY SAND with GRAVEL(SC)

PL = 13

1 1/2"1"

3/4"1/2"3/8"#4#10#20#40#100#200


100.095.088.588.583.871.256.947.037.921.516.7

Boring/Sample: B-4/4



LL = 26 PI = 13

% GRAVEL28.8

21.0

16.754.5

Since 1954


0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

0.0010.010.1110100

D30 = D10 =

Cc = Cu =

10024 16 301 20010





3 4 20 406 60


FIGURE-4

1.5

% FINES

3/4

0.0


3/8

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

coarse

2.1

% Clay% Silt

6.2 3.0 71.51.0

Atterberg Limits

% SAND% COBBLES

Coefficients

Depth: 40.0ft

D100 = 25 D60 = D50 =

LEAN CLAY with SAND(CL)

PL = 191"

3/4"1/2"3/8"#4#10#20#40#100#200


100.093.893.891.790.889.888.787.880.471.5

Boring/Sample: B-4/8



LL = 39 PI = 20

% GRAVEL9.2

16.2

71.519.3

Since 1954


0

10

20

30

40

50

60

0 20 40 60 80 100

LL PL PI Fines

22

26

39

15

13

19

14

17

71

PLASTICITY

INDEX

LIQUID LIMIT

ML or OL

ATTERBERG LIMITS RESULTS

CL or OL

CL-ML

CH or OH

MH or OH

7

13

20


Siskiyou County, California FIGURE-4


Boring/Sample Depth Description

SILTY, CLAYEY SAND with GRAVEL(SC-SM)

CLAYEY SAND with GRAVEL(SC)

LEAN CLAY with SAND(CL)

20.0

20.0

40.0

B-1 / 6

B-4 / 4

B-4 / 8

Since 1954


2011-0209

Boring/ Test NormalSample Condition Stress Shear Stress Displacement Shear Stress Displacement

(psf) (psf) (ins) (psf) (ins)

B-1/1 3 250 751 0.120 657 0.250B-1/1 3 500 893 0.170 873 0.250B-1/1 3 1,000 1,358 0.160 1,308 0.250

ALL SAMPLES SHEARED - - SPECIMEN TEST CONDITION AS NOTED - -

IN STANDARD CIRCULAR SHEAR BOX UNDER STRAIN CONTROL = 0.025 INS/MIN.

Test Condition Notation

1. Natural moisture, unconsolidated

2. Submerged, unconsolidated

3. Saturated, consolidated at test load

4. Remolded to 90% relative compaction (ASTM D 1557)

Boring/ Final Compression(-)Sample Surcharge Dry Density Moisture Moisture Expansion(+)

(psf) (pcf) (%) (%) (%)

B-1/1 250 122 8.7 16.1 -0.6B-1/1 500 120 8.7 15.1 -1.0B-1/1 1,000 117 8.7 16.1 -2.0

Initial

LABORATORY TEST RESULTS

Summary of Remolded Direct Shear Tests

Peak Values Ultimate Values

Surcharged Volume Change Tests(2.5" diameter X 1" thick specimen; 24-Hour Saturation at indicated surcharge)

Figure-4

Sunlønd Analyticøl11353 Pyrites Way, Suite 4

Rancho Cordova, CA 95670(916) 852-8ss7

Date Reported 05/L6/2012Date Submitted 05/L0/201,2

To: Alexander TaberTaber ConsultanEs3911 West CapiÈaI Avenuelrl. Sacranento, CÀ 95691-2LL6

\From: Gene Ol-iphant, Ph.Ð. \ Randy ttorn"y//f

General Marrager \ Lab Maaager' \-

The reported analysís was requested for the following location:Location ¿ 20LL-0209 Síte fD z 4/2+4/3.

Thank you for your business.

* For future reference to thís analysis please use SUN # 62261-1-28L79.

EVAI.UATION FOR SOTL CORROSION

Soil pH 7.70

Minimum Resistivity

Chloride

Sulfate

METHODSpH and MinSuLfate CA

4.29 ohm-cm

6.3 ppm

34.3 ppm

(x1000)

00.00063

00.00343

4

%

Resistivity CÀ

DOT Test #4L7,DOT Test #643Chloride CA DOT TesÈ #422

Figure-4

Sunlønd Analyticøl11353 Pyrites Way, Suite 4

Rancho Cordova, CA 95670(916) 852-8ss7

Date Reported 05/L6/20]-2Datse SubmiÈted 05/10/20L2

To: Àlexander TaberTaber Consultant's3911 West CaPiÈal AvenueW. Sacramento, CA 9569L-2LL6

From: Gene Oliphant, Ph.D. \ Randy Yorn"y/-\General Manager \ r,ab Manager \ø u

\The reporÈed analysis was requestsed for tshe following location:

LocaÈion : 2011-0209 Site ID ¿ 4/7+4/8.Thank you for Your business.

* For future reference to this analysis please use SUN # 62261-L281-80.

EVALUATION FOR SOIL CORROSTON

soíI pH 7.34

Mínimum ResistiviÈy 3.48 ohm-cm (x1000)

Chloride

Sulfate

1-0.8 ppm 00.00108 %

48.5 ppm 00.00485 %

METHODSpH and Min.ResistíviÈy CÀ DOT Tests #643Sulfate CÀ DOT Test #41-7, Chloride CA DOT Test #422

Figure-4

Liqu

efyP

ro

C

ivilT

ech

Sof

twar

e U

SA

w

ww

.civ

iltec

h.co

m

CivilTech Corporation

LIQUEFACTION ANALYSISSchulmeyer Gulch Bridge

Boring-1 Figure-5

Hole No.=1 Water Depth=7 ft Surface Elev.=2754. Magnitude=7.3Acceleration=.269g

(ft)0

10

20

30

40

50

60

70

5 138 70

13 134 80

10 142 16.7

40 143 14.2

57 148 14.2

36 146 14.2

18 136 65

26 143 65

21 145 20

35 144 20

57 145 20

Compact/very stif f SILT/CLAY w ith f ine to

coarse SAND and GRAVEL

Very soft SILT/CLAY w ith f ine to coarse

SAND

Stiff LEAN CLAY w ith trace f ine gravel

Loose CLAYEY fine to coarse SAND w ith

fine to coarse GRAVEL

Dense SILTY CLAYEY fine to coarse

SAND w ith f ine to coarse GRAVEL

Stiff LEAN CLAY w ith f ine to coars SAND

and GRAVEL

Compact to dense SILTY CLAYEY SAND

w ith GRAVEL

Raw Unit FinesSPT Weight %

Shear Stress Ratio

CRR CSR fs1Shaded Zone has Liquefaction Potential

0 1Soil Description Factor of Safety

0 51Settlement

SaturatedUnsaturat.

S = 0.68 in.

0 (in.) 1

fs1=1

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