Geotechnical Engineering Report of LAX RTR Facility, LA, CA.pdf

Geotechnical Engineering Report

LAX RTR Facility

Los Angeles, California

May 23, 2018

Terracon Project No. 60185066

Prepared for:

Parsons

Seattle, Washington

Prepared by:

Terracon Consultants, Inc.

Tustin, California

LAX RTR Facility ■ Los Angeles, California May 23, 2018 ■ Terracon Project No. 60185066

Responsive ■ Resourceful ■ Reliable

TABLE OF CONTENTS

EXECUTIVE SUMMARY………………………………………………………………………………………...i

1.0 INTRODUCTION

2.0 PROJECT INFORMATION

2.1 Project Description

2.2 Site Location and Description

3.0 SUBSURFACE CONDITIONS

3.1 Site Geology

3.2 Landslides and Landslide Potential

3.3 Typical Subsurface Profile

3.4 Groundwater

3.5 Field Soil Resistivity Test Results

3.6 Seismic Considerations

3.6.1 Seismic Site Classification Parameters

3.6.2 Faulting and Estimated Ground Motions

3.6.3 Liquefaction Potential

3.7 Corrosion Potential

4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION

4.1 Geotechnical Considerations

4.2 Earthwork

4.2.1 Site Preparation

4.2.2 Subgrade Preparation

4.2.3 Fill Materials and Placement

4.2.4 Compaction Requirements

4.2.5 Grading and Drainage

4.2.6 Utility Trenches

4.2.7 Construction Considerations

4.3 Foundations

4.4 Slope Stability Analysis

4.5 Lateral Earth Pressures

4.6 Pavements

4.6.1 Design Recommendations

4.6.2 Construction Considerations

5.0 GENERAL COMMENTS

Responsive ■ Resourceful ■ Reliable

TABLE OF CONTENTS (continued)

APPENDIX A – FIELD EXPLORATION

Exhibit A-1 Site Location Exhibit A-2 Site Geologic Map 1 Exhibit A-3 Site Geologic Map 2 Exhibit A-4 Geologic Cross Section Exhibit A-5 Landslide Hazard Map Exhibit A-6 Regional Geologic Map Exhibit A-7 Field Exploration Description

Exhibits A-8 to A-9 Boring Logs

APPENDIX B – LABORATORY TESTING

Exhibit B-1 Laboratory Test Description

Exhibit B-2 Swell Consolidation Test

Exhibit B-3 Direct Shear Test

Exhibit B-4 Results of Corrosion Analysis

APPENDIX C – SUPPORTING DOCUMENTS

Exhibit C-1 General Notes

Exhibit C-2 Unified Soil Classification

APPENDIX D – SLOPE STABILITY ANALYSIS

Exhibit D-1 Static Slope Stability Analysis

Exhibit D-2 Pseudo Static Slope Stability Analysis

APPENDIX E – ELECTRICAL RESISTIVITY TEST RESULTS

Responsive ■ Resourceful ■ Reliable i

EXECUTIVE SUMMARY

A geotechnical exploration has been performed for the proposed RTR Facility to be located just west of the Los Angeles International Airport (LAX) runway, northeast of the intersection of

Beaumont Street and Trask Avenue. Terracon’s geotechnical scope of work included the advancement of two (2) test borings to approximate depths of 21½ and 51½ feet below the ground surface (bgs).

Based on the information obtained from our subsurface exploration, the site is considered suitable for development of the proposed project provided the recommendations included within this report are implemented during the design and construction phases of the project. The following geotechnical considerations were identified:

Based on the results of the borings, subsurface conditions encountered on the project site is predominantly loose to medium dense sand to the maximum depth explored at 51½ feet bgs. A geologic cross section is presented in Exhibit A-4.

Groundwater was not observed in the test borings at the time of field exploration.

Based on the subsurface materials encountered in the project site, the proposed tower may be supported on shallow foundation bearing on a minimum of 2½ feet of engineered fill materials. Onsite materials are considered suitable to be used as engineered fill materials.

Slope stability analysis was performed for the existing slope located on the eastern boundary of the project site. Based on the analysis, the factors of safety are greater than

1.5 and 1.1 for static and pseudo station conditions, respectively.

Light (automobile) parking areas – 3” AC over 4” Class II AB or 5” PCC; On-site driveways and delivery areas – 3” AC over 7” Class II AB or 6” PCC. All pavements should be supported on a minimum of 10 inches of scarified, moisture conditioned, and compacted materials.

The 2016 California Building Code (CBC) seismic site classification for this site is D.

Earthwork on the project should be observed and evaluated by Terracon. The evaluation of earthwork should include observation and testing of engineered fill, subgrade preparation, foundation bearing soils, and other geotechnical conditions exposed during construction.

This geotechnical executive summary should be used in conjunction with the entire report for design and/or construction purposes. It should be recognized that specific details were not included or fully developed in this section, and the report must be read in its entirety for a comprehensive understanding of the items contained herein. The section titled General

Comments should be read for an understanding of the report limitations.

Responsive ■ Resourceful ■ Reliable 1

GEOTECHNICAL ENGINEERING REPORT

PROPOSED LAX RTR FACILITY

LOS ANGELES, CALIFORNIA

Terracon Project No. 60185066

May 23, 2018

1.0 INTRODUCTION

This report presents the results of our geotechnical engineering services performed for the proposed

RTR Facility to be located west of the Los Angeles International Airport (LAX) runway and

Pershing Drive on top of the hills in Los Angeles, California. The Site Location Plan (Exhibit A-1) is included in Appendix A of this report. The purpose of these services is to provide information and geotechnical engineering recommendations relative to:

subsurface soil conditions groundwater conditions earthwork foundation design and construction seismic considerations slope stability evaluations

Our geotechnical engineering scope of work for this project included the advancement of two (2) test borings to approximate depths of 21½ and 51½ feet bgs.

Logs of the borings along with a Boring Location Diagram (Exhibits A-2 and A-3) are included in

Appendix A of this report. The results of the laboratory testing performed on soil samples obtained from the site during the field exploration are included in Appendix B of this report. Descriptions of the field exploration and laboratory testing are included in their respective appendices.

2.0 PROJECT INFORMATION

2.1 Project Description

ITEM DESCRIPTION

Site layout Refer to the Boring Location Diagram (Exhibits A-2 and A-3 in

Appendix A)

Structures The proposed site development will include the construction of one (1)

RTR tower.

Finished floor elevation

(assumed) Within one foot of existing grade

Maximum loads (assumed) Columns: 450 to 550 kips

Proposed footing is 15 feet wide and 30 feet long

Grading Minimal cut/fill – assumed to be less than one foot

Responsive ■ Resourceful ■ Reliable 2

ITEM DESCRIPTION

Traffic loading (assumed)

Design Traffic Index (TI’s):

Automobile Parking Areas: 4.5

On-site Driveways and Delivery Areas: 6.0

2.2 Site Location and Description

Item Description

Location

The project site is located just west of the Los Angeles International

Airport (LAX) runway, northeast of the intersection of Beaumont Street and Trask Avenue.

Latitude: 33.9438 degrees; Longitude: -118.4371 degrees

Existing site features The proposed project area is currently occupied by existing tower with adjacent buildings.

Surrounding developments

North: Undeveloped Land

South: Access Roads followed by Undeveloped Land

East: Pershing Drive and LAX Runway

West: Trask Avenue

Current ground cover Asphalt and concrete pavements.

Existing topography

Relatively level project site. The eastern side of the project site is a descending slope. The descending slope height is about 50 feet with approximately 1.5H:1V slope orientation

3.0 SUBSURFACE CONDITIONS

3.1 Site Geology

The site is located in the Los Angeles Basin within the Peninsular Ranges Geomorphic Province, which is described by the California Geological Survey (CGS, 2002)1 as follows:

The Peninsular Ranges consist of a series of ranges separated by northwest trending valleys, subparallel to faults branching from the San Andreas Fault. The trend of topography is similar to the Coast Ranges, but the geology is more like the Sierra Nevada, with granitic rock intruding the older metamorphic rocks. The Peninsular Ranges extend into lower California and are bound on the east by the Colorado Desert. The Los Angeles

Basin and the island group (Santa Catalina, Santa Barbara, and the distinctly terraced

1 California Geological Survey, 2002, California Geomorphic Provinces – California Geological Survey Note 36.

Responsive ■ Resourceful ■ Reliable 3

San Clemente and San Nicolas islands), together with the surrounding continental shelf

(cut by deep submarine fault troughs), are included in this province.

Dibblee (2007)2, Roffers and Bedrossian (2010)3, and Saucedo and others (2016)4 mapped the natural materials underlying the site as eolian (wind-blown) and dune deposits of late Holocene age (in Exhibit A-6, map unit Qe) underlain by old eolian and dune deposits of late to middle

Pleistocene age (in Exhibit A-6, map unit Qoe). Roffers and Bedrossian (2010) described the younger eolian and dune deposits as unconsolidated, generally well-sorted wind-blown sand; may occur as dune forms or sheet sand. The underlying old eolian and dune deposits are described as slightly to moderately consolidated, moderately dissected wind-blown sands.

3.2 Landslides and Landslide Potential

Review of the Earthquake Zones of Required Investigation Map by the California Geological

Survey5 indicates the easterly facing slope below the east side of the tower site is mapped within an earthquake-induced landslides potential zone (See Exhibit A-5). This slope is also considered susceptible to failure based on the underlying relatively clean poorly sorted sand having a presumed low cohesion value. A slope stability analysis was performed to assess the stability of this existing slope due to the proposed development. The slope stability analysis for static and pseudo-static conditions are presented in Section 4.4.

3.3 Typical Subsurface Profile

Specific conditions encountered at the boring locations are indicated on the individual boring logs.

Stratification boundaries on the boring logs represent the approximate location of changes in soil types; in-situ, the transition between materials may be gradual. Details for the borings can be found on the boring logs included in Appendix A. Based on the results of the borings, subsurface conditions encountered on the project site is predominantly loose to medium dense sand to the maximum depth explored at 51½ feet bgs. A geologic cross section is presented in Exhibit A-4.

Laboratory tests were conducted on selected soil samples and the test results are presented in

Appendix B and on the boring logs. Consolidation/collapse tests indicate that the sandy materials encountered at approximate depth of 2½ feet have a slight collapse potential when saturated under normal footing loads of 2,000 psf. Direct shear tests were performed on poorly graded sand materials encountered at approximate depths of 15 and 30 feet and indicated ultimate friction angles of 28° and 33° with corresponding cohesions of 0 and 186 psf.

2 Dibblee, T.W., Jr., 2007, Geologic Map of the Venice and Inglewood Quadrangles, Los Angeles County, California: Dibblee Geology Center Map #322, scale 1:24,000.

3 California Geological Survey, July 2010, Geologic Compilation of Quaternary Surficial Deposits in Southern California, Special Report 217, Plate 8-Long Beach 30’ x 60’ Quadrangle, California, compiled by P.D. Roffers and T. L. Bedrossian.

4 California Geological Survey, 2016, Geologic Map of the Long Beach 30’ x 60’ Quadrangle, compiled by GJ. Saucedo, H.G. Greene, M.P. Kennedy, and S.P. Bezore.

5 California Geological Survey, 2016, Earthquake Zones of Required Investigation, Venice Quadrangle, scale 1:24,000.

Responsive ■ Resourceful ■ Reliable 4

3.4 Groundwater

Groundwater was not observed in the test borings at the time of field exploration. These observations represent groundwater conditions at the time of the field exploration and may not be indicative of other times, or at other locations.

Based on the County of Los Angeles, Department of Publics Works groundwater data, the groundwater level in the project vicinity ranges between elevation 3.2 and 17.8 feet above mean sea level between 1985 and 2007 6, which indicates that the groundwater is deeper than 100 feet below the project site.

3.5 Field Soil Resistivity Test Results

Field measurements of soil resistivity were performed in general accordance with ASTM Test

Method G57-06 using the Wenner Four-Electrode Method. Two perpendicular arrays were performed at the location shown on Exhibit A-2. The Wenner arrangement (equal electrode spacing) was used with the “a” spacing as shown in Appendix E. Due to the obstructions and ground cover within the project site, the test location was selected near the southeast corner of the project site. The “a” spacing in north-south direction was 2, 5, 10, 15 and 20 feet and the “a” spacing in the east-west direction was 5, 10 and 25 feet due to the obstructions and groundcover at the test location.

The “a” spacing is generally considered to be the depth of influence of the test. Results of the soil resistivity measurements are presented in Appendix E of this report.

3.6 Seismic Considerations

3.6.1 Seismic Site Classification Parameters

DESCRIPTION VALUE

2016 California Building Code Site Classification (CBC) 1 D

Site Latitude N 33.9438°

Site Longitude W 118.4371°

Ss Spectral Acceleration for a Short Period 1.614 g

S1 Spectral Acceleration for a 1-Second Period 0.617 g

6 County of Los Angeles, Department of Publics Works, groundwater monitoring well No. 1288F. The well is located about 1.8 miles south of the project site

Responsive ■ Resourceful ■ Reliable 5

DESCRIPTION VALUE

Fa Site Coefficient for a Short Period 1.000

Fv Site Coefficient for a 1-Second Period 1.500

1 Note: The 2016 California Building Code (CBC) requires a site soil profile determination extending to a depth of

100 feet for seismic site classification. The current scope does not include the required 100-foot soil profile determination. Borings were extended to a maximum depth of 51½ feet, and this seismic site class definition considers that similar or denser soils continue below the maximum depth of the subsurface exploration. Additional exploration to deeper depths would be required to confirm the conditions below the current depth of exploration.

3.6.2 Faulting and Estimated Ground Motions

The site is located in Southern California, which is a seismically active area. The type and magnitude of seismic hazards affecting the site are dependent on the distance to causative faults, the intensity, and the magnitude of the seismic event. As calculated using the USGS Unified

Hazard Tool, the Palos Verdes Fault is considered to have the most significant effect at the site from a design standpoint. This fault is located approximately 7.2 kilometers from the site and maximum credible earthquake magnitude of this fault is 6.97.

Based on the USGS Design Maps Summary Report, using the American Society of Civil

Engineers (ASCE 7-10) standard, the peak ground acceleration (PGAM) at the project site is expected to be 0.61g. Based on the USGS Unified Hazard Tool, the project site has a mean magnitude of 6.74. Furthermore, the site is not located within an Alquist-Priolo Earthquake Fault

Zone based on our review of the State Fault Hazard Maps.7

3.6.3 Liquefaction Potential

Liquefaction is a mode of ground failure that results from the generation of high pore water pressures during earthquake ground shaking, causing loss of shear strength. Liquefaction is typically a hazard where loose sandy soils exist below groundwater. The California Geologic

Survey (CGS) has designated certain areas within Southern California as potential liquefaction hazard zones. These are areas considered at a risk of liquefaction-related ground failure during a seismic event, based upon mapped surficial deposits and the presence of a relatively shallow water table. The project site was not mapped by the CGS for liquefaction potential hazard. Based on the anticipated depth to groundwater on-site, liquefaction hazard potential at the project site is considered low. Other geologic hazards related to liquefaction, such as lateral spreading, are therefore also considered low.

7 California Department of Conservation Division of Mines and Geology (CDMG), “Digital Images of Official Maps of Alquist-Priolo

Earthquake Fault Zones of California, Southern Region”, CDMG Compact Disc 2000-003, 2000.

Responsive ■ Resourceful ■ Reliable 6

3.7 Corrosion Potential

Results of soluble sulfate testing indicate that ASTM Type I/II Portland cement may be used for all concrete on and below grade Foundation concrete may be designed for sulfate exposure category class S0 in accordance with the provisions of the ACI Design Manual, Section 318, Chapter 19.

Laboratory test results indicate the on-site soils have a pH of 8.67, a minimum resistivity of

29,100 ohm-centimeters, a water soluble sulfate content of 0.02%, Red-Ox potential of +678 mV, negligible sulfides, and a chloride content of 38 parts per million (ppm) as shown on the attached

Results of Corrosivity Analysis sheet. These values should be used to evaluate corrosive potential of the on-site soils to underground ferrous metals.

Refer to the Results of Corrosivity Analysis sheet in Appendix B for the complete results of the corrosivity testing conducted in conjunction with this geotechnical exploration.

4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION

4.1 Geotechnical Considerations

The site appears suitable for the proposed construction based upon geotechnical conditions encountered in the test borings, provided the recommendations included within this report are implemented. Based on the geotechnical engineering analyses, subsurface exploration, and laboratory test results, the proposed tower may be supported on a spread foundation system.

Based on the subsurface materials encountered in the project site, the proposed tower may be supported on shallow foundation bearing on a minimum of 2½ feet of engineered fill materials.

Onsite materials are considered suitable to be used as engineered fill materials.

Geotechnical engineering recommendations for foundation systems and other earth connected phases of the project are outlined below. The recommendations contained in this report are based upon the results of field and laboratory testing (which are presented in Appendices A and B), engineering analyses, and our current understanding of the proposed project.

Based on the findings summarized in this report, it is our professional opinion that the proposed construction will not be subject to a hazard from settlement, slippage, or landslide, provided the recommendations of our report are incorporated into the proposed construction. It is also our opinion that the proposed construction will not adversely affect the geologic stability of the site or adjacent properties provided the recommendations contained in our report are incorporated into the proposed construction.

Responsive ■ Resourceful ■ Reliable 7

4.2 Earthwork

The following presents recommendations for site preparation, excavation, subgrade preparation and placement of engineered fills on the project. The recommendations presented for the design and construction of foundations and pavements are contingent upon following the recommendations outlined in this section. All grading for the proposed spread footings should incorporate the limits of the proposed construction plus a lateral distance of 2 feet beyond the perimeter of the proposed supports.

Earthwork on the project should be observed and evaluated by Terracon. The evaluation of earthwork should include observation and testing of engineered fill, subgrade preparation, foundation bearing soils, and other geotechnical conditions exposed during the construction of the project.

4.2.1 Site Preparation

Strip and remove existing pavement, demolition debris, vegetation and other deleterious materials from proposed tower support areas. Exposed surfaces should be free of mounds and depressions which could prevent uniform compaction.

Underground utility lines are anticipated within the proposed tower footprint area. Evidence of other underground facilities such as septic tanks, cesspools, and basements, was not observed during the site reconnaissance, however such features could be encountered during construction.

If fill materials, underground facilities, and/or utilities lines are encountered, such features should be removed and the excavation thoroughly cleaned prior to backfill placement and/or construction.

4.2.2 Subgrade Preparation

The proposed foundations should be supported on a minimum 2½ feet of engineered fill materials.

Compaction of subgrade should be performed following the recommendations in section 4.2.4 of this report.

Excavation bottom, once properly cleared, should be scarified to a minimum depth of 10 inches, moisture conditioned, and compacted per the compaction requirements presented in

Section 4.2.4. The over-excavation should then be backfilled up to the footing base elevation with engineered fill placed in lifts of 8 inches or less in loose thickness and should be moisture conditioned and compacted following the recommendations in section 4.2.4 of this report.

Subgrade soils beneath pavements may be scarified, moisture conditioned, and compacted to a minimum depth of 10 inches. The moisture content and compaction of subgrade soils should be maintained until pavement construction.

Responsive ■ Resourceful ■ Reliable 8

4.2.3 Fill Materials and Placement

All fill materials should be inorganic soils free of vegetation, debris, and fragments larger than three inches in size. Pea gravel or other similar non-cementitious, poorly-graded materials should not be used as fill or backfill without the prior approval of the geotechnical engineer.

Onsite materials are considered suitable to use as engineered fill materials in the foundation, pavement and general grading areas.

Imported soils should conform to low volume change materials as indicated in the following specifications:

Percent Finer by Weight

Gradation (ASTM C 136)

3”

No. 4 Sieve ................................................................................. 50 to 100

No. 200 Sieve ............................................................................... 10 to 40

Liquid Limit ....................................................................... 30 (max) Plasticity Index ................................................................. 15 (max)

Maximum expansive index* .............................................. 20 (max)

*ASTM D 4829

Engineered fill should be placed and compacted in horizontal lifts, using equipment and procedures that will produce recommended moisture contents and densities throughout the lift.

Fill lifts should not exceed ten inches loose thickness.

4.2.4 Compaction Requirements

Recommended compaction and moisture content criteria for engineered fill materials are as follows:

Material Type and Location

Per the Modified Proctor Test (ASTM D 1557)

Minimum Compaction Requirement

Range of Moisture Contents for Compaction Above Optimum

Minimum Maximum

Imported low volume change or onsite materials:

Beneath shallow foundations: 90% -1% +4%

Utility trenches*: 90% -1% +4%

Beneath pavements: 95% -1% +4%

Bottom of excavation to receive fill: 90% -1% +4%

Miscellaneous backfill: 90% -1% +4%

Aggregate base (beneath pavements): 95% -2% +2%

* Upper 12 inches should be compacted to 95% within pavement and structural areas.

Responsive ■ Resourceful ■ Reliable 9

4.2.5 Grading and Drainage

Positive drainage should be provided during construction and maintained throughout the life of the development. Infiltration of water into utility trenches or foundation excavations should be prevented during construction. Planters and other surface features which could retain water in areas adjacent to the foundation or pavements should be sealed or eliminated. In areas where paving does not immediately adjoin the foundations, we recommend that protective slopes be provided with a minimum grade of approximately 5 percent for at least 10 feet from the foundation.

Backfill against footings and in utility and sprinkler line trenches should be well compacted and free of all construction debris to reduce the possibility of moisture infiltration. Sprinkler systems and landscaped irrigation should not be installed within 5 feet of foundations.

4.2.6 Utility Trenches

It is anticipated that the on-site soils will provide suitable support for underground utilities and piping that may be installed. Any soft and/or unsuitable material encountered at the bottom of excavations should be removed and be replaced with an adequate bedding material. A non-expansive granular material with a sand equivalent greater than 30 is recommended for bedding and shading of utilities, unless otherwise allowed by the utility manufacturer.

On-site materials are considered suitable for backfill of utility and pipe trenches from one foot above the top of the pipe to the final ground surface, provided the material is free of organic matter and deleterious substances. Trench backfill should be mechanically placed and compacted as discussed earlier in this report. Compaction of initial lifts should be accomplished with hand-operated tampers or other lightweight compactors. Where trenches are placed beneath footings, the backfill should satisfy the gradation and expansion index requirements of engineered fill discussed in this report. Flooding or jetting for placement and compaction of backfill is not recommended.

4.2.7 Construction Considerations

It is anticipated that excavations for the proposed construction can be accomplished with conventional earthmoving equipment. Based upon the subsurface conditions determined from the geotechnical exploration, subgrade soils exposed during construction are anticipated to be relatively workable. However, the workability of the subgrade may be affected by precipitation, repetitive construction traffic or other factors. If unworkable conditions develop, workability may be improved by scarifying and drying.

Onsite soils consist of cohesionless sandy soils. Such soils have the tendency to cave and slough during excavations. Therefore, formwork may be needed for foundation excavations.

Upon completion of filling and grading, care should be taken to maintain the subgrade moisture content prior to construction of pavements. Construction traffic over the completed subgrade should be avoided to the extent practical. The site should also be graded to prevent ponding of surface water on the prepared subgrades or in excavations. If the subgrade should become

Responsive ■ Resourceful ■ Reliable 10 desiccated, saturated, or disturbed, the affected material should be removed or these materials should be scarified, moisture conditioned, and recompacted prior to floor slab and pavement construction.

The geotechnical engineer should be retained during the construction phase of the project to observe earthwork and to perform necessary tests and observations during subgrade preparation, proof-rolling, placement and compaction of controlled compacted fills, backfilling of excavations to the completed subgrade.

The exposed subgrade and each lift of compacted fill should be tested, evaluated, and reworked, as necessary, until approved by the geotechnical engineer’s representative prior to placement of additional lifts. We recommend that each lift of fill be tested for density and moisture content at a frequency of one test for every 2,500 square feet of compacted fill in the foundation areas and

5,000 square feet in pavement areas. We recommend one density and moisture content test for every 50 linear feet of compacted utility trench backfill.

We recommend that the earthwork portion of this project be completed during extended periods of dry weather if possible. If earthwork is completed during the wet season (typically November through April) it may be necessary to take extra precautionary measures to protect subgrade soils.

Wet season earthwork operations may require additional mitigation measures beyond that which would be expected during the drier summer and fall months. This could include diversion of surface runoff around exposed soils and draining of ponded water on the site. Once subgrades are established, it may be necessary to protect the exposed subgrade soils from construction traffic.

The individual contractor(s) is responsible for designing and constructing stable, temporary excavations as required to maintain stability of both the excavation sides and bottom.

Excavations should be sloped or shored in the interest of safety following local, and federal regulations, including current OSHA excavation and trench safety standards.

4.3 Foundations

DESCRIPTION RECOMMENDATION

Foundation Type Conventional Shallow Spread Footings for the proposed RTR

Tower

Bearing Material A minimum of 2½ feet of engineered fill materials below the bottom the footings

Allowable Bearing Pressure* 1,500 psf

Foundation Dimensions Width: 15 feet; Length: 30 feet

Minimum Embedment Depth

Below Finished Grade 18 inches

Responsive ■ Resourceful ■ Reliable 11

DESCRIPTION RECOMMENDATION

Total Estimated Settlement 1 inch

Estimated Differential Settlement ½ inch across 30 feet

*Allowable bearing capacity is based on the total settlement of 1-inch for the foundation dimensions provided by the client. Settlement calculations were performed utilizing Westergaard and Hough's methods to estimate the static settlement.

Finished grade is defined as the lowest adjacent grade within five feet of the foundation. The allowable foundation bearing pressures apply to dead loads plus design live load conditions. The design bearing pressure may be increased by one-third when considering total loads that include wind or seismic conditions. The weight of the foundation concrete below grade may be neglected in dead load computations.

Care should be taken to prevent wetting or drying of the bearing materials during construction.

Wet, dry, or loose/disturbed material in the bottom of the footing excavations should be removed before foundation concrete is placed. Place a lean concrete mud-mat over the bearing soils if the excavations must remain open for an extended period of time.

The geotechnical engineer should observe foundation excavations. If the soil conditions encountered differ significantly from those presented in this report, supplemental recommendations will be required.

4.4 Slope Stability Analysis

As shown in Exhibit A-3, one cross-section was prepared along the east-west direction at the eastern boundary of the existing slope. Static and pseudo-static slope stability analyses were performed utilizing the computer program SLIDE8. SLIDE utilizes algorithms for the Modified

Bishop method of slices for circular slip surfaces. The Modified Bishop method uses moment limit-equilibrium to determine the factor of safety. In the limit-equilibrium method, the forces resisting failure are compared against the forces tending to cause failure. This ratio, termed the factor of safety (FS), is an indication of stability of each postulated failure surface. A search is undertaken to determine the lowest factor of safety on the critical failure surface for each model.

Graphical results of the stability calculations for each cross section are included in Appendix D.

The soil parameters (shear strength and unit weight) used in the analyses are shown on the stability analyses. Our analyses utilized shear strength parameters based on field observation, laboratory test data and our experience with similar types of materials. A surcharge pressure of

1,500 psf from the proposed foundation and 250 psf from the existing building and pavement areas were considered in the analysis.

8 Rocscience Inc., Slide Version 6.0.

Responsive ■ Resourceful ■ Reliable 12

Pseudo-static slope stability analysis was also performed using one-third of the PGAM as the horizontal seismic coefficient.

Theoretically, a factor of safety of 1.0 indicates that a slope is on the verge of instability.

Therefore, any lower factor of safety should result in failure and any higher factor of safety should theoretically represent a safe slope. However, due to the uncertainties associated with any geotechnical evaluation, assumed subsurface conditions within the ascending slope areas, and the factors discussed in the preceding paragraph, all slopes, even those with factors of safety greater than 1.0, have some potential for failure. The higher the computed factor of safety is for a given slope, the lower its probability of failure will be. Acceptable factors of safety for design is greater than 1.5 under static loading and greater than 1.1 under seismic conditions based on geotechnical standard practice for conditions where the subsurface geometry and the engineering properties of these materials are well defined. Based on our evaluations, the static and pseudo-static factors of safety against slope instability are equal or greater than 1.5 and 1.1, respectively.

4.5 Lateral Earth Pressures

For engineered fill comprised of on-site soils or imported materials above any free water surface, recommended equivalent fluid pressures for unrestrained foundation elements are:

ITEM VALUE1

Active Case 38 psf/ft

Passive Case 390 psf/ft

At-Rest Case 58 psf/ft

Coefficient of friction 0.40

1Note: The values are based on-site soils or imported materials used as backfill.

The lateral earth pressures herein do not include any factor of safety and are not applicable for submerged soils/hydrostatic loading. Additional recommendations may be necessary if such conditions are to be included in the design.

Fill against foundation should be compacted to densities specified in the Earthwork section of this report. Compaction of each lift adjacent to any walls should be accomplished with hand-operated tampers or other lightweight compactors.

4.6 Pavements

4.6.1 Design Recommendations

An estimated design R-Value was used to calculate the asphalt concrete pavement thickness sections and the portland cement concrete pavement sections. R-value testing should be completed prior to pavement construction to verify the design R-value.

Responsive ■ Resourceful ■ Reliable 13

Assuming the pavement subgrades will be prepared as recommended within this report, the following pavement sections should be considered minimums for this project for the traffic indices assumed in the table below. As more specific traffic information becomes available, we should be contacted to reevaluate the pavement calculations.

Recommended Pavement Section Thickness (inches)*

Light (Automobile) Parking

Assumed Traffic Index (TI) = 4.5

On-site Driveways and Delivery

Areas Assumed TI = 6.0

Section I

Portland Cement Concrete

(600 psi Flexural Strength)

5-inches PCC 6-inches PCC

Section II

Asphaltic Concrete

3-inches AC over 4-inches Class II Aggregate Base

3-inches AC over 7-inches Class II Aggregate Base

* All materials should meet the CALTRANS Standard Specifications for Highway Construction.

All pavements should be supported on a minimum of 10 inches of scarified, moisture conditioned, and compacted materials. These pavement sections are considered minimal sections based upon the expected traffic and the existing subgrade conditions. However, they are expected to function with periodic maintenance and overlays if good drainage is provided and maintained.

Subsequent to clearing, grubbing, and removal of topsoil, subgrade soils beneath all pavements should be scarified, moisture conditioned, and compacted to a minimum depth of 10 inches. All materials should meet the CALTRANS Standard Specifications for Highway Construction.

Aggregate base materials should meet the gradation and quality requirement of Class 2

Aggregate Base (¾ inch maximum) in Caltrans Standard Specifications, latest edition, Sections

25 through 29.

All concrete for rigid pavements should have a minimum flexural strength of 600 psi (4,250 psi

Compressive Strength), and be placed with a maximum slump of four inches. Proper joint spacing will also be required to prevent excessive slab curling and shrinkage cracking. All joints should be sealed to prevent entry of foreign material and dowelled where necessary for load transfer.

4.6.2 Construction Considerations

Materials and construction of pavements for the project should be in accordance with the requirements and specifications of the State of California Department of Transportation, or other approved local governing specifications.

Base course or pavement materials should not be placed when the surface is wet. Surface drainage should be provided away from the edge of paved areas to minimize lateral moisture transmission into the subgrade.

Preventative maintenance should be planned and provided for through an on-going pavement management program in order to enhance future pavement performance. Preventative

Responsive ■ Resourceful ■ Reliable 14 maintenance activities are intended to slow the rate of pavement deterioration, and to preserve the pavement investment.

Preventative maintenance consists of both localized maintenance (e.g. crack sealing and patching) and global maintenance (e.g. surface sealing). Preventative maintenance is usually the first priority when implementing a planned pavement maintenance program and provides the highest return on investment for pavements.

5.0 GENERAL COMMENTS

Terracon should be retained to review the final design plans and specifications so comments can be made regarding interpretation and implementation of our geotechnical recommendations in the design and specifications. Terracon also should be retained to provide observation and testing services during grading, excavation, foundation construction and other earth-related construction phases of the project.

The analysis and recommendations presented in this report are based upon the data obtained from the borings performed at the indicated locations and from other information discussed in this report. This report does not reflect variations that may occur between borings, across the site, or due to the modifying effects of construction or weather. The nature and extent of such variations may not become evident until during or after construction. If variations appear, we should be immediately notified so that further evaluation and supplemental recommendations can be provided.

The scope of services for this project does not include either specifically or by implication any environmental or biological (e.g., mold, fungi, bacteria) assessment of the site or identification or prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the potential for such contamination or pollution, other studies should be undertaken.

This report has been prepared for the exclusive use of our client for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranties, either express or implied, are intended or made. Site safety, excavation support, and dewatering requirements are the responsibility of others. In the event that changes in the nature, design, or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless Terracon reviews the changes and either verifies or modifies the conclusions of this report in writing.

APPENDIX A

FIELD EXPLORATION

SITE LOCATION

PTSI: LAX RTR Facility

LAX

Los Angeles, CA

TOPOGRAPHIC MAP IMAGE COURTESY OF THE U.S. GEOLOGICAL SURVEY

QUADRANGLES INCLUDE: VENICE, CA (1/1/1981).

1421 Edinger Ave Ste C Tustin, CA 92780-6287

60185066 Project Manager:

Drawn by:

Checked by:

Approved by:

DTB

RP

FB

1”=2,000’

A-1

04/2018

Project No.

Scale:

File Name:

Date:

A-1

ExhibitRP

SITE

B-1 BORING APPROXIMATE LOCATION

B-1

B-2

A-2 1421 Edinger Avenue Ste C Tustin, California 92780

PH. (949) 261-0051 FAX. (949) 261-6110

60185066

04/2018

1”≈35’

Project Manager:

Drawn by:

Checked by:

Approved by:

Project No.

Scale:

File Name:

Date:

Exhibit

A-2

DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS

NOT INTENDED FOR CONSTRUCTION PURPOSES

LEGEND

ER-1

ER-1 ELECTRICAL RESISTIVITY TESTING LOCATION

A A’

Qe = Eolian or Dune Deposits (Late Holocene) Qoe = Old Eolian or Dune Deposits (Pleistocene)

! Approximate geologic contact

! Geologic cross section

Qe

Qe

Qoe

Qoe

A A’

SITE GEOLOGIC MAP 1

LAX RTR Facility Los Angeles, CA

SP

DTB

SP

FFB

SITE GEOLOGIC MAP 2

Los Angeles, CA A-3

1421 Edinger Avenue Ste C Tustin, California 92780

PH. (949) 261-0051 FAX. (949) 261-6110

60185066

04/2018

SP

DTB

SP

FFB

AS SHOWN

Project Manager:

Drawn by:

Checked by:

Approved by:

Project No.

Scale:

File Name:

Date:

Exhibit

A-3

GEOLOGIC CROSS SECTION

A-4

MAY 2018

SJ AS SHOWN

Project Manager:

Drawn by:

Checked by:

Approved by:

Project No.

Scale:

File Name:

Date:

Exhibit

A-4DIAGRAM IS FOR GENERAL LOCATION

ONLY, AND IS NOT INTENDED FOR

CONSTRUCTION PURPOSES

50 Goldenland Court, Suite 100 Sacramento, CA 95834

PH. (916) 928-4690 FAX. (916) 928-4694

LAX RTR Facility

Los Angeles, CA

60185066SP

SP

FFB

LANDSLIDE HAZARD MAP

Los Angeles, CA A-5

1421 Edinger Avenue Ste C Tustin, California 92780

PH. (949) 261-0051 FAX. (949) 261-6110

60185066

05/2018

SP

DTB

SP

FFB

AS SHOWN

Project Manager:

Drawn by:

Checked by:

Approved by:

Project No.

Scale:

File Name:

Date:

Exhibit

A-5

DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS

NOT INTENDED FOR CONSTRUCTION PURPOSES

REGIONAL GEOLOGIC MAP

A-6 1421 Edinger Avenue, Ste C Tustin, CA 92780

PH. (949) 261-0051 FAX. (949) 261-6110

60185066

MAY 2018

SP

SEJ

SP

FFB

As shown

Project Manager:

Drawn by:

Checked by:

Approved by:

Project No.

Scale:

File Name:

Date:

Exhibit

A-6DIAGRAM IS FOR GENERAL LOCATION

ONLY, AND IS NOT INTENDED FOR

CONSTRUCTION PURPOSES

Los Angeles, CA

Exhibit A-7

Field Exploration Description

A total of two (2) test borings were drilled at the site on April 18, 2018. The borings were drilled to approximate depths of 21½ and 51½ feet bgs at the approximate locations shown on the attached Boring Location Diagram, Exhibit A-2. The test borings were advanced with a track-mounted CME-75 drill rig utilizing 8-inch diameter hollow-stem augers.

The borings were located in the field by using the proposed site plan, aerial photographs of the site, handheld GPS device, and measuring from existing site features. The accuracy of boring locations should only be assumed to the level implied by the method used.

Continuous lithologic logs of the borings were recorded by the field engineer during the drilling operations. At selected intervals, samples of the subsurface materials were taken by driving split-spoon or ring-barrel samplers. Bulk samples of subsurface materials were also obtained.

Groundwater conditions were evaluated in the borings at the time of site exploration.

Penetration resistance measurements were obtained by driving the split-spoon and ring-barrel samplers into the subsurface materials with a 140-pound automatic hammer falling 30 inches.

The penetration resistance value is a useful index in estimating the consistency or relative density of materials encountered.

An automatic hammer was used to advance the split-barrel sampler in the borings performed on this site. A significantly greater efficiency is achieved with the automatic hammer compared to the conventional safety hammer operated with a cathead and rope. This higher efficiency has an appreciable effect on the SPT-N value. The effect of the automatic hammer's efficiency has been considered in the interpretation and analysis of the subsurface information for this report.

The samples were tagged for identification, sealed to reduce moisture loss, and taken to our laboratory for further examination, testing, and classification. Information provided on the boring logs attached to this report includes soil descriptions, consistency evaluations, boring depths, sampling intervals, and groundwater conditions. The borings were backfilled with auger cuttings prior to the drill crew leaving the site.

6-8-8

1-3-3 N=6

6-10-15

4-6-8 N=14

10-16-25

POORLY GRADED SAND (SP)

trace silt, light brown, loose no silt, tan medium dense

G R

A P

H

IC

L O

G

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

T H

IS

B

O R

IN

G

L O

G

IS

N O

T V

A

LI

D

IF

S E

P A

R A

T E

D F

R O

M O

R

IG

IN

A

L R

E P

O R

T

G E

O S

M A

R T

L O

G -N

O W

E

LL

B

O R

IN

G

L O

G S

.G P

J T

E R

R A

C O

N _D

A T

A T

E M

P

LA

T E

.G D

T

/2 4/

C O

M P

R E

S S

IV

E

S T

R E

N G

T H

(t sf

S T

R A

IN

T E

S T

T Y

P E

P E

R C

E N

T F

IN

E

S

W A

T E

R C

O N

T E

N T

D R

Y U

N

IT

W E

IG

H

T pc f)

LL-PL-PI

ATTERBERG

LIMITS

ELEVATION (Ft.)

Approximate Surface Elev: 136 (Ft.) +/-

W A

T E

R L

E V

E L

O B

S E

R V

A T

IO

N

S

D E

P T

H

F t.)

S A

M P

LE

T

Y P

E STRENGTH TEST

F

IE

LD

T

E S

T R

E S

U

LT

S

LAX

Los Angeles, CA

SITE:

Advancement Method:

HSA

Abandonment Method:

Boring backfilled with Auger Cuttings and/or Bentonite

Notes:

Project No.: 60185066

Drill Rig: LAR

Boring Started: 04-18-2018

BORING LOG NO. B-1

ParsonsCLIENT:

Seattle, WA

Driller: 2R Drilling

Boring Completed: 04-18-2018

Exhibit: A-8

See Exhibit A-7 for description of field proce-dures.

See Appendix B for description of laboratory procedures and additional data (if any).

See Appendix C for explanation of symbols and abbreviations.

Elevation estimated with Google Earth.

PROJECT: LAX RTR Facility

1421 Edinger Ave Ste C Tustin, CA

WATER LEVEL OBSERVATIONS

Not encountered

DEPTH

LOCATION See Exhibit A-2

Latitude: 33.9439° Longitude: -118.4372°

4-8-9 N=17

15-16-26

8-10-14 N=24

12-22-36

4-8-7 N=15

POORLY GRADED SAND (SP) (continued) with silt, brown

G R

A P

H

IC

L O

G

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

T H

IS

B

O R

IN

G

L O

G

IS

N O

T V

A

LI

D

IF

S E

P A

R A

T E

D F

R O

M O

R

IG

IN

A

L R

E P

O R

T

G E

O S

M A

R T

L O

G -N

O W

E

LL

B

O R

IN

G

L O

G S

.G P

J T

E R

R A

C O

N _D

A T

A T

E M

P

LA

T E

.G D

T

/2 4/

C O

M P

R E

S S

IV

E

S T

R E

N G

T H

(t sf

S T

R A

IN

T E

S T

T Y

P E

P E

R C

E N

T F

IN

E

S

W A

T E

R C

O N

T E

N T

D R

Y U

N

IT

W E

IG

H

T pc f)

LL-PL-PI

ATTERBERG

LIMITS

ELEVATION (Ft.)

Approximate Surface Elev: 136 (Ft.) +/-

W A

T E

R L

E V

E L

O B

S E

R V

A T

IO

N

S

D E

P T

H

F t.)

S A

M P

LE

T

Y P

E STRENGTH TEST

F

IE

LD

T

E S

T R

E S

U

LT

S

LAX

Los Angeles, CA

SITE:

Advancement Method:

HSA

Abandonment Method:

Boring backfilled with Auger Cuttings and/or Bentonite

Notes:

Project No.: 60185066

Drill Rig: LAR

Boring Started: 04-18-2018

BORING LOG NO. B-1

ParsonsCLIENT:

Seattle, WA

Driller: 2R Drilling

Boring Completed: 04-18-2018

Exhibit: A-8

See Exhibit A-7 for description of field proce-dures.

See Appendix B for description of laboratory procedures and additional data (if any).

See Appendix C for explanation of symbols and abbreviations.

Elevation estimated with Google Earth.

PROJECT: LAX RTR Facility

1421 Edinger Ave Ste C Tustin, CA

WATER LEVEL OBSERVATIONS

Not encountered

DEPTH

5 113 84.5+/-

15-24-27 51.5

POORLY GRADED SAND (SP) (continued)

Boring Terminated at 51.5 Feet

G R

A P

H

IC

L O

G

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

T H

IS

B

O R

IN

G

L O

G

IS

N O

T V

A

LI

D

IF

S E

P A

R A

T E

D F

R O

M O

R

IG

IN

A

L R

E P

O R

T

G E

O S

M A

R T

L O

G -N

O W

E

LL

B

O R

IN

G

L O

G S

.G P

J T

E R

R A

C O

N _D

A T

A T

E M

P

LA

T E

.G D

T

/2 4/

C O

M P

R E

S S

IV

E

S T

R E

N G

T H

(t sf

S T

R A

IN

T E

S T

T Y

P E

P E

R C

E N

T F

IN

E

S

W A

T E

R C

O N

T E

N T

D R

Y U

N

IT

W E

IG

H

T pc f)

LL-PL-PI

ATTERBERG

LIMITS

ELEVATION (Ft.)

Approximate Surface Elev: 136 (Ft.) +/-

W A

T E

R L

E V

E L

O B

S E

R V

A T

IO

N

S

D E

P T

H

F t.)

S A

M P

LE

T

Y P

E STRENGTH TEST

F

IE

LD

T

E S

T R

E S

U

LT

S

LAX

Los Angeles, CA

SITE:

Advancement Method:

HSA

Abandonment Method:

Boring backfilled with Auger Cuttings and/or Bentonite

Notes:

Project No.: 60185066

Drill Rig: LAR

Boring Started: 04-18-2018

BORING LOG NO. B-1

ParsonsCLIENT:

Seattle, WA

Driller: 2R Drilling

Boring Completed: 04-18-2018

Exhibit: A-8

See Exhibit A-7 for description of field proce-dures.

See Appendix B for description of laboratory procedures and additional data (if any).

See Appendix C for explanation of symbols and abbreviations.

Elevation estimated with Google Earth.

PROJECT: LAX RTR Facility

1421 Edinger Ave Ste C Tustin, CA

WATER LEVEL OBSERVATIONS

Not encountered

DEPTH

113.5+/-

6-9-12

3-3-4 N=7

7-6-8

3-5-6 N=11

21.5

POORLY GRADED SAND (SP), tan trace black, medium dense loose medium dense

Boring Terminated at 21.5 Feet

G R

A P

H

IC

L O

G

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

T H

IS

B

O R

IN

G

L O

G

IS

N O

T V

A

LI

D

IF

S E

P A

R A

T E

D F

R O

M O

R

IG

IN

A

L R

E P

O R

T

G E

O S

M A

R T

L O

G -N

O W

E

LL

B

O R

IN

G

L O

G S

.G P

J T

E R

R A

C O

N _D

A T

A T

E M

P

LA

T E

.G D

T

/2 4/

C O

M P

R E

S S

IV

E

S T

R E

N G

T H

(t sf

S T

R A

IN

T E

S T

T Y

P E

P E

R C

E N

T F

IN

E

S

W A

T E

R C

O N

T E

N T

D R

Y U

N

IT

W E

IG

H

T pc f)

LL-PL-PI

ATTERBERG

LIMITS

ELEVATION (Ft.)

Approximate Surface Elev: 135 (Ft.) +/-

W A

T E

R L

E V

E L

O B

S E

R V

A T

IO

N

S

D E

P T

H

F t.)

S A

M P

LE

T

Y P

E STRENGTH TEST

F

IE

LD

T

E S

T R

E S

U

LT

S

LAX

Los Angeles, CA

SITE:

Advancement Method:

HSA

Abandonment Method:

Boring backfilled with Auger Cuttings and/or Bentonite

Notes:

Project No.: 60185066

Drill Rig: LAR

Boring Started: 04-18-2018

BORING LOG NO. B-2

ParsonsCLIENT:

Seattle, WA

Driller: 2R Drilling

Boring Completed: 04-18-2018

Exhibit: A-9

See Exhibit A-7 for description of field proce-dures.

See Appendix B for description of laboratory procedures and additional data (if any).

See Appendix C for explanation of symbols and abbreviations.

Elevation estimated with Google Earth.

PROJECT: LAX RTR Facility

1421 Edinger Ave Ste C Tustin, CA

WATER LEVEL OBSERVATIONS

Not encountered

DEPTH

APPENDIX B

LABORATORY TESTING

Exhibit B-1

Laboratory Testing

Samples retrieved during the field exploration were taken to the laboratory for further observation by the project geotechnical engineer and were classified in accordance with the Unified Soil

Classification System (USCS) described in Appendix C. At that time, the field descriptions were confirmed or modified as necessary and an applicable laboratory testing program was formulated to determine engineering properties of the subsurface materials.

Laboratory tests were conducted on selected soil samples and the test results are presented in this appendix. The laboratory test results were used for the geotechnical engineering analyses, and the development of foundation and earthwork recommendations. Laboratory tests were performed in general accordance with the applicable ASTM, local or other accepted standards.

Selected soil samples obtained from the site were tested for the following engineering properties:

ASTM D7263 Dry Density ASTM D2216 Moisture Content

CT422 Chloride Content CT417 Soluble…