Geotechnical Evaluation Report

12/15/2017 Geotechnical Evaluation Report

Proposed New U-Haul Facility Northeast Corner of Interstate 25 and County Road 12 Dacono, Colorado D17-2-076

Use or copying of this document is strictly prohibited

December 15, 2017

A report prepared for:

Ed Kobziak, PM U-Haul International/Amerco Real Estate Contruction Department 2727 N. Central Avenue Phoenix, Arizona 85004 [email protected]

GEOTECHNICAL EVALUATION REPORT Proposed New U-Haul Facility Northeast Corner of Interstate 25 and County Road 12 Dacono, Colorado VIVID Project No.: D17-2-076

Prepared by:

Brysen T. Mustain, P.G. Project Geologist

12/15/17

William J. Barreire, P.E. Senior Geotechnical Engineer

VIVID Engineering Group, Inc. 1053 Elkton Drive Colorado Springs, CO 80907 (719) 896-4356 (719) 896-4357 fax

Table of Contents

1.0 INTRODUCTION ...... 1 1.1 General ...... 1 1.2 Project Description ...... 1 1.3 Purpose and Scope ...... 1 2.0 FIELD EXPLORATION AND LABORATORY TESTING ...... 3 2.1 Field Exploration ...... 3 2.2 Geotechnical Laboratory Testing ...... 3 2.3 Analytical Laboratory Testing ...... 3 3.0 SITE CONDITIONS ...... 4 3.1 Surface ...... 4 3.2 Geology ...... 4 3.3 Seismicity ...... 4 3.4 Subsurface ...... 5 3.4.1 Groundwater ...... 5 4.0 CONCLUSIONS AND RECOMMENDATIONS ...... 7 4.1 Geotechnical Feasibility of Proposed Construction ...... 7 4.2 Construction Considerations ...... 8 4.2.1 General ...... 8 4.2.2 Site Preparation and Grading ...... 8 4.2.3 Excavation Characteristics ...... 8 4.2.4 Fill Materials ...... 9 4.2.5 Utility Trench Backfill ...... 10 4.2.6 Compaction Requirements ...... 10 4.2.7 Construction in Wet or Cold Weather ...... 11 4.2.8 Construction Testing and Observation ...... 11 4.2.9 Surface Drainage and Landscaping ...... 11 4.2.10 Permanent Cut and Fill Slopes ...... 12 4.3 FOUNDATION RECOMMENDATIONS ...... 12 4.3.1 Drilled Pier Foundation System Recommendations ...... 12 4.3.1.1 Drilled Pier Recommendations ...... 12

4.3.1.2 Pier Construction ...... 13 4.3.2 Lateral Pier Resistance Parameters ...... 14 4.3.3 Shallow Foundation System Recommendations ...... 14 4.4 FLOOR SLABS ...... 15 4.4.1 Structural Floor System ...... 15 4.4.2 Slab-on-Grade Floor System ...... 16 4.4.3 Capillary Break or Moisture Barrier ...... 17 4.5 EXTERIOR CONCRETE SLABS-ON-GRADE...... 17 4.6 CHEMICAL SULFATE SUSCEPTIBILITY AND CONCRETE TYPE ...... 17 4.7 PAVEMENT RECOMMENDATIONS ...... 18 4.7.1 General ...... 18 4.7.2 Traffic Values ...... 18 4.7.3 Pavement Subgrade Preparation ...... 18 4.7.4 Pavement Construction Considerations ...... 19 5.0 ADDITIONAL SERVICES & LIMITATIONS ...... 20 5.1 ADDITIONAL SERVICES ...... 20 5.2 LIMITATIONS ...... 20

Figure 1: Vicinity Map

Figure 2: Exploration Location Plan

Figure 3: Pavement Subgrade Schematic

Appendix A: Logs of Exploratory Borings

Appendix B: Geotechnical Laboratory Test Results

Appendix C: Analytical Laboratory Test Results

Appendix D: Important Information About This Geotechnical Engineering Report

1.0 INTRODUCTION 1.1 General This report presents the results of a geotechnical investigation performed for a proposed new U-Haul Facility to be constructed at the northeast corner of Interstate 25 and County Road 12 in Dacono, Colorado. An attached Vicinity Map (Figure 1) shows the general location of the project. Our investigation was performed for U-Haul International/Amerco Real Estate and was authorized by Mr. Ed Kobziak.

This report includes our recommendations relating to the geotechnical aspects of project design and construction. The conclusions and recommendations stated in this report are based upon the subsurface conditions found at the locations of our exploratory borings at the time our exploration was performed. They also are subject to the provisions stated in the report section titled Additional Services & Limitations . Our findings, conclusions, and recommendations should not be extrapolated to other areas or used for other projects without our prior review. Furthermore, they should not be used if the site has been altered, or if a prolonged period has elapsed since the date of the report, without VIVID’s prior review to determine if they remain valid. 1.2 Project Description We understand the project includes construction of a new, up to 4-story tall U-Haul building and associated pavement areas on a vacant 3.89-acre site in Dacono, Colorado. Site configuration of the building and pavement areas as well as grading plans were not provided at the time this report was published but grading is anticipated to be minimal (on the order of 3-feet or less) to reach finished site grades. Structural loads for the building were also not provided but are anticipated to range from relatively light to heavy depending on final building height and configuration. No below-grade construction (i.e. basement area) is anticipated.

If the type of construction or actual building loads vary significantly from those assumed above, VIVID should be notified in order to revise our recommendations, if required. 1.3 Purpose and Scope The purpose of our investigation was to explore and evaluate subsurface conditions at various locations on the site and, based upon the conditions found, to develop recommendations relating to the geotechnical aspects of project design and construction. Our conclusions and recommendations in this report are based upon analysis of the data from our field exploration, laboratory tests, and our experience with similar soil and geologic conditions in the area.

VIVID’s scope of services included:

• A visual reconnaissance to observe surface and geologic conditions at the project site and locating the exploratory borings; • Notification of the Utility Notification Center of Colorado (UNCC)/Colorado 811 one-call service to identify underground utility lines at the boring locations prior to our drilling; • The drilling of 6 exploratory borings at various locations on the property, which were selected based upon the proposed access and location of existing structures and utilities;

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• Laboratory testing of selected samples obtained during the field exploration to evaluate relevant physical and engineering properties of the soil; • Evaluation and engineering analysis of the field and laboratory data collected to develop our geotechnical conclusions and recommendations; and • Preparation of this report, which includes a description of the proposed project, a description of the surface and subsurface site conditions found during our investigation, our conclusions and recommendations as to foundation and floor slab design and construction, pavement design for the proposed parking areas, other related geotechnical issues, and appendices which summarize our field and laboratory investigations.

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2.0 FIELD EXPLORATION AND LABORATORY TESTING 2.1 Field Exploration A field exploration performed on November 6, 2017 included drilling 6 exploratory borings at the approximate locations indicated on the Exploration Location Plan (Figure 2). The borings were drilled at locations that were evenly spread across the site, and were advanced to depths of approximately 20 to 40-feet below the existing ground surface. Borings were advanced using a truck-mounted CME-55 drill rig equipped with 4-inch, continuous-flight, solid-stem auger. Samples were taken with a standard split- spoon sampler, modified California sampler, and by bulk methods. Penetration tests were obtained at the various sample depths as well.

Appendix A to this report includes logs describing the subsurface conditions. The lines defining boundaries between soil types on the logs are based upon drill behavior and interpolation between samples, and are therefore approximate. Transition between soil types may be abrupt or may be gradual. 2.2 Geotechnical Laboratory Testing Laboratory tests were performed on selected soil samples to estimate their relative engineering properties. Tests were performed in general accordance with the following methods of ASTM or other recognized standards-setting bodies, and local practice:

• Description and Identification of Soils (Visual-Manual Procedure) • Classification of Soils for Engineering Purposes • Moisture Content and Unit Weight of Soils • Sieve Analysis of Fine and Coarse Aggregates • Liquid Limit, Plastic Limit, and Plasticity Index of Soils • Swell/Settlement Test Results of the geotechnical laboratory tests are presented in the report text, where applicable, and included in Appendix B of this report. Selected test results are also shown on the boring logs in Appendix A. 2.3 Analytical Laboratory Testing Analytical testing for water-soluble sulfates was performed on two samples. Results of the analytical laboratory tests are included in Appendix C of this report.

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3.0 SITE CONDITIONS 3.1 Surface At the time of our exploration, the subject site was located on a vacant 3.89-acre parcel located on the northeast corner of Interstate 25 and County Road 12 (Grandview Blvd.). The site was covered in grass and weeds and sloped gently towards the south. Interstate 25 was located to the west of the site, County Road 12 was located to the south, and Silver Peak Avenue was present to the east of the site. Other commercial properties were present surrounding the site. 3.2 Geology Prior to drilling, the site geology was evaluated by reviewing available geologic information. Mapping in the area indicates the surficial soils in the general area of the project site comprise predominantly alluvium deposits of sand, silt, and clay underlain by sandstone and claystone of the Laramie Formation. The mapping is generally consistent with our explorations. 3.3 Seismicity Based upon the geologic setting, subsurface soil conditions, and low seismic activity in this region, liquefaction is not expected to be a hazard at the site. Based on correlation of blow count data (N-values) from the borings advanced during this evaluation, the subsurface soil profiles correspond with Site Class D of the 2012 International Building Code (IBC). The intermediate design acceleration values from IBC are presented below.

Table 1

Design Acceleration for Short Periods

SS Fa 0.1 78 1.6

SS = The mapped spectral accelerations for short periods (U.S. Geological Survey Web Page, 2017)

Fa = Site coefficient from Table 1613.3.3(1), 2012 IBC

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Table 2

Design Acceleration for 1-Second Period

S1 FV 0. 05 7 2.4

S1 = The mapped spectral accelerations for 1-second period (U.S. Geological Survey Web Page, 2017)

Fv = Site coefficient from Table 1613.3.3(2), 2012 IBC

3.4 Subsurface VIVID explored the subsurface conditions by drilling, logging and sampling 6 exploratory borings within or near the general area to be occupied by the proposed building and new pavement areas as shown on Figure 2. These borings were drilled to depths ranging from approximately 20 to 40-feet below the existing ground surface. The general profile encountered in our borings consisted of:

Clay

Deposits comprised of sandy lean clay were encountered underlying a thin layer of topsoil at the ground surface and extended to depths between approximately 13 to 17-feet below the ground surface in all borings. The clay soils were tan to brown, moist to wet, and field penetration testing (blow counts) indicated the relative density of the clay soils were generally low, but ranged from very soft to firm. The clay soils will provide variable support characteristics including elastic and consolidation settlement of low density, very moist to wet materials. Swell/settlement testing performed on the samples indicated soil compression on the order of 4 to 6 percent under surcharge pressures on the order of 2000 psf.

Sandstone and Claystone

Weathered to comparatively unweathered sandstone or claystone bedrock of the Laramie Formation was encountered in all borings at depths between approximately 13 and 17-feet below the ground surface and extended to the maximum depths explored of approximately 20 to 40-feet below the grounds surface. The bedrock materials were tan to olive-brown with iron oxide staining, moist to very moist, and medium hard to very hard. Bedrock in most of the borings was sufficiently hard to provide good support for deep foundation elements within a relatively short vertical distance into the bedrock. Boring B-1, however, had a significant zone of weathered (softer) bedrock material that did not get consistently harder until approximately 36-feet below the ground surface. Field penetration testing (blow counts) indicated the relative density of the bedrock materials soils ranged from medium hard to very hard.

The boring logs in appendix A should be reviewed for more detailed descriptions of the subsurface conditions at each of the boring locations explored. 3.4.1 Groundwater Groundwater was encountered in all of our explorations at the time of drilling at depths ranging between approximately 10 and 11-feet below the ground surface. Groundwater is anticipated to be a significant 5 | Page December 15, 2017 D17-2-076

consideration in design and construction especially if deep foundation elements or other deep excavations are planned. Soil moisture levels and groundwater levels commonly vary over time and space depending on seasonal precipitation, irrigation practices, land use, and runoff conditions. These conditions and the variations that they create often are not apparent at the time of field investigation. Accordingly, the soil moisture and groundwater data in this report pertain only to the locations and times at which exploration was performed. They can be extrapolated to other locations and times only with caution. It should also be noted that VIVID has not performed a hydrologic study to verify the seasonal high-water level.

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4.0 CONCLUSIONS AND RECOMMENDATIONS

4.1 GEOTECHNICAL FEASIBILITY OF PROPOSED CONSTRUCTION VIVID found generally poor (soft and compressible) subsurface conditions during this investigation that would indicate that development of the site essentially as planned involves a greater risk of low performance of the structure and pavements than is typically acceptable without some type of mitigation. However, provided the recommendations in this report are incorporated in the design and construction of the project, the effects of the poor soil subgrade can be significantly minimized.

A significant potential for structural damage due to long-term elastic and consolidation settlement of low- density, very moist to wet clay soils exists for structures founded directly on the existing materials. Additionally, floor slabs founded directly on the existing materials would be subject to differential settlement over the long-term. Results of settlement testing indicate that settlement on the order of 4 to 6 percent is likely under even light footing pressures on the order of 2,000 psf. This could result is shallow foundation settlements on the order of 2 to 4-inches under this magnitude of footing pressure. Several mitigation options for foundation system and floor slab support were evaluated. The variable support characteristics and settlement potential of the site soils dictate the type of foundation and floor construction most suitable for the proposed project, as outlined below.

Based upon the data obtained from our subsurface investigation and our assumption that minimal (less than approximately 3-feet) of site grading will be required to develop the property, the major geotechnical issues involved in developing this site are the presence of low-density/soft/wet clay soils with potential for long-term and differential settlement at the anticipated foundation and floor elevations. In order to mitigate the potential risk of building damage due to the low-density soils, the following are some of the major geotechnical recommendations to be implemented as part of this project:

• We recommend the building be supported on a deep foundation system comprised of straight- shaft drilled piers bottomed in the underlying unweathered bedrock. • If the building will be a maximum of one story in height, shallow foundation elements (i.e. isolated pads, strip footings) may be utilized, but should be supported by a thick layer of geosynthetic reinforced soil (see Section 4.3.3 and Schematic 1). • A structurally-supported floor system is the more reliable option to prevent damage from differential movement from long-term settlement of subsurface clay soils if feasible. Floors consisting of slabs-on-grade should be supported by a layer imported structural fill (see Section 4.4.2). • As pavements will also be subject to long-term differential settlement we recommend pavement subgrade materials below pavement areas be removed and replaced with a zone of imported granular structural fill (see Section 4.7). • Exterior grading to direct surface water away from the building area will be of paramount importance.

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It should be noted that all of the above recommendations are somewhat preliminary as the final type and location of construction has not been defined. Final design may be optimized to the final building type, loads, locations, and grading once that information is known . Our geotechnical design and construction recommendations for site preparation, foundations, floor systems, pavements, and other related construction topics are provided in the following sections. 4.2 CONSTRUCTION CONSIDERATIONS 4.2.1 General All site preparation and earthwork operations should be performed in accordance with applicable codes, safety regulations and other local, State or Federal guidelines. 4.2.2 Site Preparation and Grading Initial site work should consist of completely removing all structures, foundation elements, and utilities, as required, as well as removing any pockets of loose soils, debris, organics, and other deleterious materials from all areas to be filled and areas to be cut. All material should be removed for offsite disposal in accordance with local laws and regulations or, if appropriate, stockpiled in proposed landscaped areas for future use. Areas to receive fill should be evaluated by the geotechnical engineer prior to the placement of any fill materials.

After performing the required excavations and prior to the placement of any compacted fill and/or structural elements, processing of the subgrade should be performed. This should include scarifying the subgrade to a depth of at least 8-inches, and compacting as recommended in Section 4.2.6 of this report. All fill materials should be placed on a horizontal plane and placed in loose lifts not to exceed 8-inches in thickness, unless otherwise accepted by the geotechnical engineer. It should be noted that existing clay soils are near or above optimum moisture content in many cases, therefore unstable subgrade conditions should be anticipated. To address this, techniques can vary from scarification, drying and re-compaction, to stabilization with rock and/or geogrid and aggregate materials.

We highly recommend tracked/low ground pressure equipment be utilized to perform earthwork operations and install fill and pavement elements. This will help limit damage to the stabilized subgrade and reduce the required amount of stabilization. Consideration should also be given to the time of year for construction to minimize potential for precipitation during earthwork activities. 4.2.3 Excavation Characteristics Existing and proposed site grading plans were not provided to us prior to compilation of this report. We anticipate localized cuts and fills on the order of 1 to 3-feet will be performed for general site grading. Utility installation has not been reviewed, but similar high moisture content to wet conditions (below approximately 10-feet) should be anticipated during utility installation. Groundwater levels shown on the boring logs should be reviewed for any deeper excavations for utilities, etc. Dewatering will be required if excavations penetrate below the existing groundwater levels. Moisture contents of clay soils are near or above optimum moisture content in many cases, therefore processing and drying of these materials would be required prior to re-use.

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All excavations must comply with applicable local, State and Federal safety regulations, and particularly with the excavation standards of the Occupational Safety and Health Administration (OSHA). Construction site safety, including excavation safety, is the sole responsibility of the Contractor as part of its overall responsibility for the means, methods and sequencing of construction operations. VIVID’s recommendations for excavation support are intended for the Client’s use in planning the project, and in no way relieve the Contractor of its responsibility to construct, support and maintain safe slopes. Under no circumstances should the following recommendations be interpreted to mean that VIVID is assuming responsibility for either construction site safety or the Contractor’s activities.

We believe that the soils on this site will classify as Type C materials using OSHA criteria. OSHA requires that unsupported cuts be laid back to ratios no steeper than 1½:1 (horizontal to vertical). In general, we believe that these slope ratios will be temporarily stable under unsaturated conditions. If groundwater seepage was to occur, flatter slopes will be required. Please note that the actual determination of soil type and allowable sloping must be made in the field by an OSHA-qualified “competent person.” 4.2.4 Fill Materials Site Grading Fill:

On-site soils may be used for general site grading. If imported site grading fill is required at this site, it should consist of a non-expansive, granular material with a maximum particle size of 2-inches, a liquid limit of less than 30 percent, and a plasticity index of less than 6 percent. The fill should have between about 10 and 30 percent passing the No. 200 sieve. A sample of any imported site grading fill material should be submitted to our office for approval and testing at least 1-week prior to stockpiling at the site.

Imported Structural Fill:

Imported structural fill for use below foundations and floor slabs, as pavement subbase, and retaining wall backfill will be required at this site, and should consist of materials meeting the CDOT Class 1 Structure Backfill specifications, as described in Section 703.08 of the 2011 CDOT Standard Specifications for Road and Bridge Construction. For structural fill used with the GRSF foundation system, we recommend use of CDOT Class 4 or 5 Aggregate Base Course per Section 703.03 of the 2011 CDOT Standard Specifications for Road and Bridge Construction Product specific gradations for specific geogrid material may also be utilized for geogrid reinforced fill below foundations and floor slabs. A sample of any imported structural fill material should be submitted to our office for approval and testing at least 1-week prior to stockpiling at the site. Specific recommendations in regard to depth of structural fill is presented in the following sections of this report for foundations, floor slabs, etc.

Pavement Aggregate Base Course:

Aggregate base course below pavements should consist of materials meeting the CDOT Class 5 or 6 aggregate base course specifications, as described in Section 703.03 of the 2011 CDOT Standard Specifications for Road and Bridge Construction. A sample of any imported aggregate base course material should be submitted to our office for approval and testing at least 1-week prior to stockpiling at the site.

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Fill should be compacted according to the recommendations in Section 4.2.6 of this report. We recommend that a qualified representative of VIVID visit the site during excavation and during placement of the structural fill to verify the soils exposed in the excavations are consistent with those encountered during our subsurface exploration and that proper foundation subgrade preparation and placement is performed. 4.2.5 Utility Trench Backfill Backfill material should comprise imported structural fill and be essentially free of plant matter, organic soil, debris, trash, other deleterious matter and rock particles larger than 3-inches. However, backfill material in the “pipe zone” (from the trench floor to 1-foot above the top of pipe) should not contain rock particles larger than 1-inch. Strictly observe any requirements specified by the utility agency for bedding and pipe-zone fill. In general, backfill above the pipe zone in utility trenches should be placed in lifts of 6 to 8-inches, and compacted using power equipment designed for trench work. Backfill in the pipe zone should be placed in lifts of 8-inches or less and compacted with hand-held equipment. Compact trench backfill as recommended in Section 4.2.6 of this report. 4.2.6 Compaction Requirements Fill materials should be placed in horizontal lifts compatible with the type of compaction equipment being used, moisture conditioned, and compacted in accordance with the following criteria:

Table 3 Compaction Specifications PERC ENT MATERIAL MOISTURE FILL LOCATION 2 COMPACTION 1 TYPE CONTENT (ASTM D 1557) On-site Soils -2 to +3% Subgrade Preparation (all areas) (8-inches Scarified, Moisture 90 minimum 3 of Treated, Re-Compacted) optimum Structural Fill placed beneath Imported Structural Fill ± 2 % of foundations and slabs-on-grade, 95 minimum (see Section 4.2.4) optimum pavement subbase Retaining Wall / Foundation Wall Imported Structural Fill ± 2 % of 92 minimum Backfill (see Section 4.2.4) optimum Pavement Section Imported Structural Fill ± 2 % of 95 minimum Aggregate Base Course (see Section 4.2.4) optimum Imported Structural Fill ± 2 % of Exterior Flatwork Areas 92 minimum (see Section 4.2.4) optimum On-site Soils/Imported Site ± 2 % of General Site Grading Fill 92 minimum Grading Fill (see Section 4.2.4) optimum Imported Structural Fill ± 2 % of Utility Trenches 92 minimum (see Section 4.2.5) optimum 1) In non-structural or landscaped areas, the compaction specification may be reduced to 90 percent. 10 | Page December 15, 2017 D17-2-076

2) Where two or more “Fill Locations” coincide, the more stringent specification should be used. 3) If subgrade conditions are unstable and cannot meet the required compaction, stabilization techniques using rock or geogrid/aggregate stabilization can be used in lieu of meeting the minimum compaction requirement.

Fill should be placed in level lifts not exceeding 8-inches in loose thickness, and compacted to the specified percent compaction to produce a firm and unyielding surface. If field density tests indicate the required percent compaction has not been obtained, the fill material should be reconditioned as necessary and recompacted to the required percent compaction before placing any additional material.

4.2.7 Construction in Wet or Cold Weather Construction in wet weather will be problematic on this site due to the moisture-sensitive clayey soils. During construction, grade the site such that surface water can drain readily away from the building area. Promptly pump out or otherwise remove any water that may accumulate in excavations or on subgrade surfaces, and allow these areas to dry before resuming construction. The use of berms, ditches and similar means may be used to prevent stormwater from entering the work area and to convey any water off site efficiently.

If earthwork is performed during the winter months when freezing is a factor, no grading fill, structural fill or other fill should be placed on frosted or frozen ground, nor should frozen material be placed as fill. Frozen ground should be allowed to thaw or be completely removed prior to placement of fill. A good practice is to cover the compacted fill with a “blanket” of loose fill to help prevent the compacted fill from freezing.

If the buildings are erected during cold weather, foundations, concrete slabs-on-grade, or other concrete elements should not be constructed on frozen soil. Frozen soil should be completely removed from beneath the concrete elements, or thawed, scarified and recompacted. The amount of time passing between excavation or subgrade preparation and placing concrete should be minimized during freezing conditions to prevent the prepared soils from freezing. The use of blankets, soil cover or heating as required may be utilized to prevent the subgrade from freezing. 4.2.8 Construction Testing and Observation Testing and construction observation should take place under the direction of VIVID to support that engineer’s professional opinion as to whether the earthwork does or does not substantially conform to the recommendations in this report. Furthermore, the opinions and conclusions of a geotechnical report are based upon the interpretation of a limited amount of information obtained from the field exploration. It is therefore not uncommon to find that actual site conditions differ somewhat from those indicated in the report. The geotechnical engineer should remain involved throughout the project to evaluate such differing conditions as they appear, and to modify or add to the geotechnical recommendations as necessary. 4.2.9 Surface Drainage and Landscaping Positive drainage away from the structures is essential to the performance of foundations and flatwork, and should be provided during the life of the structures. Landscape areas within 10-feet of the structures should slope away at a minimum of 8 percent. Areas where pavements or slabs are constructed adjacent

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to the structures should slope away at a minimum grade of 2 percent. All downspouts from roof drains should be tight-lined to the on-site stormwater system or, at a minimum, cross all backfilled areas such that they discharge all water away from the backfill zone and the structures. Drainage should be created such that water is diverted off the site and away from backfill areas of adjacent buildings. Landscaping improvements requiring supplemental watering are not recommended adjacent to improved areas including foundations, pavements or slabs. 4.2.10 Permanent Cut and Fill Slopes If required, permanent cut and fill slopes exposing the materials encountered in our borings are anticipated to be stable at slope ratios as steep as 3:1 (horizontal to vertical) under dry conditions. We believe that slope ratios of 4:1 or flatter are more reliable if subjected to wetting, and present less of a maintenance problem. New slopes should be revegetated as soon as possible after completion to reduce erosion problems. 4.3 FOUNDATION RECOMMENDATIONS 4.3.1 Drilled Pier Foundation System Recommendations Due to the presence of low density/soft/wet clay soils at the proposed foundation elevations, it is recommended that the proposed building structure be supported on a deep foundation system consisting of straight-shaft drilled piers bottomed within the underlying bedrock. For the purposes of this report, BEDROCK is defined as the zone of relatively unweathered claystone or sandstone material that is considered appropriate for “socketing” the piers to achieve the end bearing and skin friction criteria presented below. This zone of BEDROCK is depicted by the lower portions of the boring logs labeled as CLAYSTONE or SANDSTONE presented in Appendix A, attached to this report. The depth considered appropriate for supporting deep foundation elements is on the order of 16 to 18-feet below the ground surface at boring locations B-2 through B-6. Due to a significant weathered zone encountered in boring B-1 the depth to competent bedrock is much deeper, at a depth of approximately 36-feet. The following provides our design and construction recommendations for a drilled pier foundation system. These recommendations assume pier diameters of approximately 18 to 36-inches will be utilized.

4.3.1.1 Drilled Pier Recommendations Piers should be designed in accordance with the following criteria:

• Compression load capacity of piers should be designed based on a maximum allowable end bearing pressure of 25,000 pounds per square foot (psf) and a skin friction value of 2,500 psf for the portion of pier in the BEDROCK only.

• Piers should have a minimum bedrock penetration of 6-feet into the BEDROCK. Final “design” drilled length will be developed by the project structural engineer based on the actual structure loads for individual piers and the geotechnical parameters provided. Final “constructed” pier depths should be determined by the geotechnical engineer in the field at the time of construction based on the actual conditions encountered.

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• Calculations for additional uplift resistance should be based upon an uplift skin friction value of two-thirds of the compressive side friction for the portion of pier within the BEDROCK strata, which equates to 1,667 psf.

• Piers should be designed by a qualified structural engineer. Piers should be reinforced their full length. Reinforcement should extent into grade beams or foundation walls.

• Piers should have a center-to-center spacing of at least three pier diameters when designing for vertical loading conditions, or they should be designed as a group. Piers aligned in the direction of lateral forces should have a center-to-center spacing of at least 6 pier diameters before group reduction factors are applied. Grouped pier reduction factors can be provided if required. 4.3.1.2 Pier Construction We recommend the pier drilling contractor be familiar and experienced with pier drilling operations in this area. The construction criteria presented below should be observed for a straight-shaft drilled pier foundation system. Due to existing groundwater conditions, use of drilling mud and temporary casing will be required to install drilled piers on this site. The construction details should be considered when preparing project documents.

• A drilling rig for excavation of the drilled piers of sufficient size to penetrate the hard, formational bedrock the required amount should be mobilized. This report and boring log information should be provided to drilled pier contractors prior to obtaining construction bids so they can review soil, bedrock, and groundwater information.

• The sides and base of the drilled shaft excavation should expose undisturbed soil or bedrock cleaned of remolded and loose material prior to placement of concrete. Piers should be filled with concrete immediately after they are drilled, cleaned and observed. Pier holes should not be left open overnight.

• It is very important to avoid “mushrooming” or widening of the top of the pier hole. Where required, we recommend the use of “sonotube” or other equivalent product to preserve the diameter of this section of the pier. The sonotube should be placed prior to pouring the upper portion of the pier.

• Concrete used in the drilled piers should be a fluid mix with a slump in the range of 5 to 7-inches to properly consolidate in pier holes. The higher end should be targeted where temporary casing is utilized.

• Drilled pier holes should be properly cleaned prior to placement of concrete. Concrete should be placed in drilled piers immediately after drilling to reduce the risk of contamination from groundwater and mud into the pier holes.

• Drilled pier foundations should only be attempted by a caisson drilling company that has proven experience with these subsurface conditions. Drilling companies must review the geotechnical report and evaluate subsurface conditions prior to supplying bids. Groundwater was encountered

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in our borings during drilling operations. Where groundwater cannot be controlled (no more than 3-inches of groundwater in the hole at time of pour), then the concrete should be pumped from the bottom of the hole to the top in order to displace the water. Piers should be filled with concrete immediately after they are drilled, cleaned and inspected. Open pier holes should not be left overnight. Mud buckets and temporary casing must be available at the site during construction.

• The pier drilling contractor should mobilize equipment of sufficient size to achieve required penetration into the hard bedrock strata and have available equipment necessary for groundwater control.

• It is important that the installation of drilled piers be observed by a VIVID representative to identify the proper bearing strata, observe construction techniques, and confirm subsurface conditions are as anticipated from our exploratory borings. 4.3.2 Lateral Pier Resistance Parameters Engineering properties of the subsurface materials that will aid in the analysis of laterally loaded piers for analytical programs such as L-PILE are provided in the table below. Lateral resistance within the upper 5- feet of the pier shaft should be ignored.

Table 4

LPILE Soil Parameters

Effective Undrained Friction Strain Soil Unit Depth (ft) P-Y Curve Model Cohesion Angle Factor, Modulus, Weight (psf) (deg) ε k (pci) (pcf) 1 50

110 Soft Clay (AWT) 5 to 13 200 n/a 0.020 30 (Sandy Lean CLAY) 47.6 (BWT)

Stiff Clay w/o Free Water 13 to 40 120 2,000 n/a 0.005 500 (Claystone/Sandstone)

1) AWT = Above Water Table, BWT = Below Water Table 4.3.3 Shallow Foundation System Recommendations If the building will be maximum of 1-story in height, a shallow footing or mat foundation system bearing on a layer of geosynthetic reinforced soil foundation (GRSF) overlying properly prepared subgrade is a viable option.

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Information regarding foundation structural loads were not provided at the time this report was prepared. Design recommendations for a GRSF system is highly dependent upon anticipated structural loads as well as footing widths, depths, and dimensions. However, for planning purposes a typical GRSF system comprises over-excavation of the foundation subgrade soils to depths on the order of 5 to 8-feet below the bottom of foundation elements and replacement with imported granular structural fill (CDOT Class 4 or 5 Aggregate Base Course) and installation of 3 to 4 layers of geogrid materials within the compacted fill at specific intervals (e.g. near the bottom of the over-excavation/fill layer, near the middle of the fill layer, and near the top of the fill layer.) A conceptual schematic of the GRSF system for a single footing or mat is presented below.

Schematic 1

Typical GRSF Configuration

Once final building structural loads and configuration are known, VIVID can provide GRSF recommendations for the proposed structure, if desired. 4.4 FLOOR SLABS 4.4.1 Structural Floor System From a geotechnical standpoint (i.e. soil-structure interaction), a structural floor system tied into a drilled pier foundation system is the more reliable floor system and would mitigate the risk of damage resulting from settlement of low density/wet/soft clay soils.

Where a structural floor system (crawl-space construction) is utilized, various items should be considered in the design and construction that are beyond the scope of this report. These include design

15 | Page December 15, 2017 D17-2-076

considerations associated with clearance, ventilation, insulation, as appropriate, and other issues addressed through standard construction practice and local building codes. There is the potential for moisture to develop in crawl spaces through transpiration of the moisture within native soils underlying the structure, water intrusion from snowmelt and precipitation, and surface runoff or infiltration of water through irrigation of lawns and landscaping and along utility trenches/bedding materials.

Excessive moisture or sustained elevated humidity can increase the potential for mold to develop on organic building materials. Building systems that address moisture and humidity should be properly designed by a qualified professional in this practice.

Underfloor plumbing should be located within the void space (i.e. suspended from the floor) where possible. Where plumbing is required to be buried within the subgrade soil below the floor it is very important to utilize flexible joints and durable/flexible pipe materials such that breaks/leaks will not occur due to settlement of low density site soils. Plumbing breaks/leaks will allow concentrated moisture/water to infiltrate the subgrade causing settlement and foundation movement that can damage the superstructure. 4.4.2 Slab-on-Grade Floor System Similar to a shallow foundation system, slab-on-grade floor systems are a viable option but will be subject to differential movement and associated damage due to the poor on-site soils. In order to provide for more uniform and firm subgrade support, deep over-excavation on the order of 3-feet for lightly-loaded slab areas (e.g. office areas) to 5-feet (if slabs will support heavy equipment or vehicle loads) of the soft clayey soils beneath the floor slab and replacement with structural fill would be required in order to reduce the risk of slab movement and damage. Modifications may be required based on final grading and structural loads.

Subgrade preparation, as well as structural fill requirements and placement criteria, are presented in Sections 4.2.2, 4.2.4 and 4.2.6 of this report. Due to moisture conditions existing subgrade may require stabilization with use of rock or geogrid and aggregate prior to placement of structural fill. Provided the above-noted recommendations are followed, the criteria presented below should be observed for design and construction of floor slabs on this site. The recommendations described above apply to all areas of interior slab as well as exterior flatwork that is constructed directly adjacent the building structure.

The criteria presented below should be observed for design and construction of floor slabs on this site. The construction details should be considered when preparing the project documents.

• For concrete slab-on-grade design purposes, a modulus of subgrade reaction of 200 pci can be used for properly compacted imported structural fill. Additional reinforcement can also be used to help resist damage due to differential movement of slabs. • Floor slabs should be separated from all bearing walls and columns with expansion joints that allow unrestrained vertical movement. At overhead and pedestrian door thresholds only, both interior and exterior slabs can be dowelled into the foundation stem wall to resist movement that can create a trip hazard or impede proper door operation and use.

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• Interior non-bearing partitions resting on floor slabs, as well as plumbing penetrations through the floor slab, can be provided with slip joints or similar features so that, if the slabs move, the movement cannot be transmitted to the interior walls or superstructure. • Floor slab control joints should be used to reduce damage due to shrinkage cracking. Control joint spacing is a function of slab thickness, aggregate size, slump and curing conditions. The requirements for concrete slab thickness, joint spacing and reinforcement should be established by the designer based on experience, recognized design guidelines and the intended slab use. Placement and curing conditions will have a strong impact on the final concrete slab integrity.

If vibrating machinery will be installed in the building, the machine foundations should be physically isolated from other foundations and slabs to reduce vibration damage. The design of such foundations requires special analysis that is beyond the scope of this investigation. Please contact VIVID for additional analysis and recommendations if machine vibrations will be an issue at this building. 4.4.3 Capillary Break or Moisture Barrier A capillary break or moisture barrier is not required where interior slabs are constructed on imported granular structural fill per Section 4.2.4 of this report. 4.5 EXTERIOR CONCRETE SLABS-ON-GRADE The project will include exterior concrete slabs-on-grade for walkways, sidewalks, driveways etc. Some potential for differential movement and cracking is possible if the slabs are constructed directly upon the undocumented fill clayey soils. While it is not likely that exterior slabs can be economically protected from distress, several techniques are available to reduce the expected long-term movement of the slab, including:

• Placement of a thick zone of imported, granular, non-expansive structural fill beneath slabs, • Avoidance of watering adjacent to slabs, and • Structural reinforcement of slabs.

Note that exterior slabs constructed directly adjacent the building structure shall be constructed on prepared subgrade the same as the interior floor slab per Section 4.4.2 of this report. 4.6 CHEMICAL SULFATE SUSCEPTIBILITY AND CONCRETE TYPE The degradation of concrete or cement grout can be caused by chemical agents in the soil or groundwater that react with concrete to either dissolve the cement paste or precipitate larger compounds within the concrete, causing cracking and flaking. The concentration of water-soluble sulfates in the soils is a good indicator of the potential for chemical attack of concrete or cement grout. The American Concrete Institute (ACI) in their publication Guide to Durable Concrete (ACI 201.2R-08) provides guidelines for this assessment.

The concentration of water-soluble sulfates measured on subsurface bedrock materials submitted for testing represents a Class 0 exposure of sulfate attack on concrete exposed to the soils per CDOT Standard Specifications for Road and Bridge Construction, 2011, Section 601.04. The concentration of water- soluble sulfates measured on subsurface clay soils submitted for testing represents a Class 2 exposure of

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sulfate attack on concrete exposed to the soils per CDOT Standard Specifications for Road and Bridge Construction, 2011, Section 601.04. 4.7 PAVEMENT RECOMMENDATIONS 4.7.1 General A paved parking lot is proposed for the site. Our borings indicate the pavement subgrade soils will generally consist of existing low-density clay materials. These types of soils are generally considered to provide poor support for pavements. Laboratory testing from samples obtained from the upper 5-feet of the borings correlate to a subgrade support value (R-value) of 5. All subgrade preparation, fill, and aggregate base course shall be compacted as recommended in Sections 4.2.2, 4.2.4, and 4.2.6 of this report. 4.7.2 Traffic Values No traffic estimates were available for our use at the time this report was written. Based on past experience with similar projects, we anticipate areas of the pavement will be subjected to “light” passenger vehicle traffic, while other areas will be subject to moving trucks, delivery trucks, trash trucks, and maintenance vehicles. For our design we have assigned a 20-year, 18 kip Equivalent Single Axle Load (ESAL) of 50,000 for areas of light duty vehicle use only, and an ESAL of 125,000 where heavier traffic loads area anticipated.

If traffic estimates vary significantly from those assumed, we should be contacted to re-evaluate our recommendations. The following pavement sections were designed using the AASHTO design methods for flexible pavements and the Weld County Engineering & Construction Criteria manual.

Table 5 Pavement Section Thickness Recommendations PORTLAND CEMENT CONCRETE / ASPHALT CONCRETE / PAVEMENT AGGREGATE BASE COURSE AGGREGATE BASE COURSE AREA (INCHES) 1 (INCHES) 1

Light Duty Use 6/6 3/6

Heavy Duty Use 6/6 4/7 1) Overlying at least 6-inches of imported, compacted structural fill subbase materials and properly prepared subgrade. (See Figure 3 attached to this report) Concrete pavements should be provided with adequate reinforcement based upon anticipated loads. Asphalt does not perform well where trucks perform tight turn maneuvers, therefore concrete should be considered for these areas. A concrete pad is recommended in front of trash dumpster locations to support the heavy front wheel loads of trash trucks. 4.7.3 Pavement Subgrade Preparation Settlement/compression from low density clayey soils can create an uneven surface, higher maintenance, and possibly premature failure within the pavement and other long-term performance issues. We recommend in order to reduce differential movement due to the low density clayey soils, and to create a 18 | Page December 15, 2017 D17-2-076

more uniform and stable subgrade, pavement subgrade should be over-excavated at least 6-inches, followed by construction of at least 6-inches of imported structural fill materials (pavement subbase) and compacted in accordance with the subbase and subgrade preparation compaction requirements in Table 3 (Section 4.2.6) of this report, prior to placement of the pavement section whether Hot Mix Asphalt (HMA) or Portland cement concrete (PCC) pavement is utilized. A schematic of the pavement subgrade preparation is shown on Figure 3 attached to this report. Prior to placing the pavement section and subbase materials, the prepared subgrade should be proof- rolled with a heavily loaded pneumatic-tired vehicle (such as a fully loaded water truck) after preparation. Pavement design procedures assume a firm and stable subgrade. Areas that deform under heavy wheel loads are not stable and should be removed to firm material and replaced to achieve a stable subgrade prior to paving. Care should be taken to ensure areas around manholes or other utility protrusions are proof-rolled adequately. Laboratory test results indicate that the clayey subgrade soils are at risk of pumping during construction due to their existing moisture content. This risk is increased if pavements are being constructed during adverse weather conditions (e.g. heavy precipitation). In this event, stabilization options can only be determined when the conditions are observed, but may include deeper Aggregate Base Course sections in combination with additional geo-grid placement, structural fill, rock stabilization, or similar options. 4.7.4 Pavement Construction Considerations Pavement construction must be completed in strict accordance with Weld County Engineering & Construction Criteria manual. The specifications contain requirements for the roadway materials (asphalt concrete and base course) and the construction practices used (compaction and material sampling). Of particular importance are those specifications directed towards embankment construction, subgrade compaction, base course compaction, and utility trench compaction. Prior to pavement construction, the prepared subgrade should be proof-rolled with heavy construction equipment. A fully loaded water truck would be acceptable for this purpose. During proof-rolling, particular attention should be directed to the area immediately adjacent to manholes, valves, catch basins, and other similar surface features. Areas which exhibit excessive deflection during proof-rolling should be over-excavated and stabilized as required. If soil is imported to the subject site for final grading, the soil materials must be of a character similar to those described in this report.

Proper drainage is of paramount importance in enhancing pavement performance. To avoid distress to pavement from wet subgrade soils, we recommend the maintenance of good drainage away from all pavements. Possible water sources include storm runoff, irrigation of landscaping adjacent the pavement and localized groundwater seepage, among others. Landscaping adjacent to the pavements should be avoided. Joints in the pavement or at asphalt/concrete interfaces should be sealed. Any cracks or openings in the finished pavement surface should be sealed and/or repaired as quickly as possible.

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5.0 ADDITIONAL SERVICES & LIMITATIONS

5.1 ADDITIONAL SERVICES Attached to this report is a document by the Geoprofessional Business Association (GBA) that summarizes limitations of geotechnical reports as well as additional services that are required to further confirm subgrade materials are consistent with that encountered at the specific boring locations presented in this report. This document should be read in its entirety before implementing design or construction activities. Examples of other services beyond completion of a geotechnical report are necessary or desirable to complete a project satisfactorily include:

• Review of design plans and specifications to verity that our recommendations were properly interpreted and implemented. • Attendance at pre-bid and pre-construction meetings to highlight important items and clear up misunderstandings, ambiguities, or conflicts with design plans and specifications. • Performance of construction observation and testing which allows verification that existing materials at locations beyond our borings are consistent with that presented in our report, construction is compliant with the requirements/recommendations, evaluation of changed conditions. 5.2 LIMITATIONS This work was performed in a manner consistent with that level of care and skill ordinarily exercised by other members of VIVID’s profession practicing in the same locality, under similar conditions and at the date the services are provided. Our conclusions, opinions, and recommendations are based on a limited number of observations and data. It is possible that conditions could vary between or beyond the data evaluated. VIVID makes no other representation, guarantee, or warranty, express or implied, regarding the services, communication (oral or written), report, opinion, or instrument of service provided.

This report may be used only by the Client and the registered design professional in responsible charge and only for the purposes stated for this specific engagement within a reasonable time from its issuance, but in no event later than two (2) years from the date of the report.

The work performed was based on project information provided by Client. If Client does not retain VIVID to review any plans and specifications, including any revisions or modifications to the plans and specifications, VIVID assumes no responsibility for the suitability of our recommendations. In addition, if there are any changes in the field to the plans and specifications, Client must obtain written approval from VIVID’s engineer that such changes do not affect our recommendations. Failure to do so will vitiate VIVID’s recommendations.

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Figures

Project No: D17-2-076 Figure Vicinity Map Date: October 27, 2017 Drawn by: WJB Proposed New U-Haul Facility 1 NE Corner of I-25 and CR12 Reviewed by: WJB Dacono, Colorado

Project No: D17-2-076 Figure Exploration Location Plan Date: October 27, 2017 Drawn by: WJB Proposed New U-Haul Facility 2 NE Corner of I-25 and CR12 Reviewed by: WJB Dacono, Colorado

Project No: D17 -2- Figure Date: 2017 Drawn by: BTM Review ed by: WJB

Appendix A

Logs of Exploratory Borings Vivid Engineering Group, Inc. BORING NUMBER B-1 1053 Elkton Drive PAGE 1 OF 2 Colorado Springs, CO 80907 Telephone: 719-896-4356 Fax: 719-896-4357 CLIENT AMERCO Real Estate Company PROJECT NAME Proposed New U-Haul Facility PROJECT NUMBER D17-2-076 PROJECT LOCATION NE Corner of I-25 and CR12, Dacono, Colorado DATE STARTED 11/6/17 COMPLETED 11/6/17 GROUND ELEVATION HOLE SIZE 4 inches DRILLING CONTRACTOR Custom Auger (CME-55) GROUND WATER LEVELS: DRILLING METHOD 4" Solid Stem Auger AT TIME OF DRILLING 11.00 ft LOGGED BY S. Noonan CHECKED BY W. Barreire AT END OF DRILLING --- NOTES Southeast corner of lot AFTER DRILLING ---

TESTS MATERIAL DESCRIPTION (ft) LOG BLOW DEPTH COUNTS NUMBER GRAPHIC (N VALUE) SAMPLE TYPE SAMPLE 0 0.5 Topsoil and Grass - 6-inches Sandy Lean CLAY, tan, very moist to wet, very stiff to firm GB MC = 24.4%

MC 2-3 MC = 20.4% 5 DD = 104.8 pcf LL = 28 PL = 18

10 MC 5-5

MC 5-10 MC = 17.4% 15 DD = 114.9 pcf Fines = 67.0% 16.0 Weathered SANDSTONE, tan, moist, medium hard to hard

MC 50 20 20.0 Weathered CLAYSTONE, olive brown with iron oxide staining, moist to very moist, medium hard

25 MC 16-18

30 MC 9-17

GENERALS:\VIVID - PROJECTS\D17-2-076_U-HAUL11:57 BH STD US DACONO,12-11-17.GPJ / TP WELL - GINT LAB.GDT12/15/17 - - CO\DRAFTING\D17-2-076 35 (Continued Next Page) Vivid Engineering Group, Inc. BORING NUMBER B-1 1053 Elkton Drive PAGE 2 OF 2 Colorado Springs, CO 80907 Telephone: 719-896-4356 Fax: 719-896-4357 CLIENT AMERCO Real Estate Company PROJECT NAME Proposed New U-Haul Facility PROJECT NUMBER D17-2-076 PROJECT LOCATION NE Corner of I-25 and CR12, Dacono, Colorado

TESTS MATERIAL DESCRIPTION (ft) LOG BLOW DEPTH COUNTS NUMBER GRAPHIC (N VALUE) SAMPLE TYPE SAMPLE 35

36.0 CLAYSTONE, olive brown with iron oxide staining, slightly moist, hard

MC 50 39.6 Bottom of borehole at 39.6 feet. GENERALS:\VIVID - PROJECTS\D17-2-076_U-HAUL11:57 BH STD US DACONO,12-11-17.GPJ / TP WELL - GINT LAB.GDT12/15/17 - - CO\DRAFTING\D17-2-076 Vivid Engineering Group, Inc. BORING NUMBER B-2 1053 Elkton Drive PAGE 1 OF 1 Colorado Springs, CO 80907 Telephone: 719-896-4356 Fax: 719-896-4357 CLIENT AMERCO Real Estate Company PROJECT NAME Proposed New U-Haul Facility PROJECT NUMBER D17-2-076 PROJECT LOCATION NE Corner of I-25 and CR12, Dacono, Colorado DATE STARTED 11/6/17 COMPLETED 11/6/17 GROUND ELEVATION HOLE SIZE 4 inches DRILLING CONTRACTOR Custom Auger (CME-55) GROUND WATER LEVELS: DRILLING METHOD 4" Solid Stem Auger AT TIME OF DRILLING 11.00 ft LOGGED BY S. Noonan CHECKED BY W. Barreire AT END OF DRILLING --- NOTES Middle/South end of lot AFTER DRILLING ---

TESTS MATERIAL DESCRIPTION (ft) LOG BLOW DEPTH COUNTS NUMBER GRAPHIC (N VALUE) SAMPLE TYPE SAMPLE 0 0.6 Topsoil and Grass - 7-inches Sandy Lean CLAY, brown, very moist to wet, very soft to firm GB MC = 15.9%

5 MC 5-4

MC 1-2 MC = 26.3% 10 DD = 95.2 pcf

15 MC 9-10

16.0 SANDSTONE, tan and reddish-brown, moist, hard

MC 50 19.8 Bottom of borehole at 19.8 feet. GENERALS:\VIVID - PROJECTS\D17-2-076_U-HAUL11:57 BH STD US DACONO,12-11-17.GPJ / TP WELL - GINT LAB.GDT12/15/17 - - CO\DRAFTING\D17-2-076 Vivid Engineering Group, Inc. BORING NUMBER B-3 1053 Elkton Drive PAGE 1 OF 1 Colorado Springs, CO 80907 Telephone: 719-896-4356 Fax: 719-896-4357 CLIENT AMERCO Real Estate Company PROJECT NAME Proposed New U-Haul Facility PROJECT NUMBER D17-2-076 PROJECT LOCATION NE Corner of I-25 and CR12, Dacono, Colorado DATE STARTED 11/6/17 COMPLETED 11/6/17 GROUND ELEVATION HOLE SIZE 4 inches DRILLING CONTRACTOR Custom Auger (CME-55) GROUND WATER LEVELS: DRILLING METHOD 4" Solid Stem Auger AT TIME OF DRILLING 10.00 ft LOGGED BY S. Noonan CHECKED BY W. Barreire AT END OF DRILLING --- NOTES Southwest corner of lot AFTER DRILLING ---

TESTS MATERIAL DESCRIPTION (ft) LOG BLOW DEPTH COUNTS NUMBER GRAPHIC (N VALUE) SAMPLE TYPE SAMPLE 0 0.7 Topsoil and Grass - 8-inches Sandy Lean CLAY, brown, moist to wet, soft to firm GB MC = 14.6%

5 MC 4-6

MC 4-4 MC = 22.2% 10 DD = 105.9 pcf Fines = 63.0%

MC 5-11 MC = 16.1% 15 LL = 31 PL = 15

17.0 SANDSTONE/CLAYSTONE, tan and reddish-brown, moist, medium hard to hard

20 MC 50

MC 50 24.8 Bottom of borehole at 24.8 feet. GENERALS:\VIVID - PROJECTS\D17-2-076_U-HAUL11:57 BH STD US DACONO,12-11-17.GPJ / TP WELL - GINT LAB.GDT12/15/17 - - CO\DRAFTING\D17-2-076 Vivid Engineering Group, Inc. BORING NUMBER B-4 1053 Elkton Drive PAGE 1 OF 1 Colorado Springs, CO 80907 Telephone: 719-896-4356 Fax: 719-896-4357 CLIENT AMERCO Real Estate Company PROJECT NAME Proposed New U-Haul Facility PROJECT NUMBER D17-2-076 PROJECT LOCATION NE Corner of I-25 and CR12, Dacono, Colorado DATE STARTED 11/6/17 COMPLETED 11/6/17 GROUND ELEVATION HOLE SIZE 4 inches DRILLING CONTRACTOR Custom Auger (CME-55) GROUND WATER LEVELS: DRILLING METHOD 4" Solid Stem Auger AT TIME OF DRILLING 10.00 ft LOGGED BY S. Noonan CHECKED BY W. Barreire AT END OF DRILLING --- NOTES Northeast corner of lot AFTER DRILLING ---

TESTS MATERIAL DESCRIPTION (ft) LOG BLOW DEPTH COUNTS NUMBER GRAPHIC (N VALUE) SAMPLE TYPE SAMPLE 0 0.5 Topsoil and Grass - 6-inches Sandy Lean CLAY, some thin sand lenses, tan, very moist to wet, very soft to soft GB MC = 27.8%

MC 3-4 MC = 15.6% 5 Fines = 59.0%

MC 1-1 MC = 21.9% 10 DD = 136.4 pcf LL = 30 PL = 11

14.0 Weathered SANDSTONE, tan, moist, medium hard 15 MC 21-29

18.0 SANDSTONE, tan, moist, hard to very hard MC 50/5" 20

MC 50/5" 25

29.1 MC 50/1" Bottom of borehole at 29.1 feet. GENERALS:\VIVID - PROJECTS\D17-2-076_U-HAUL11:57 BH STD US DACONO,12-11-17.GPJ / TP WELL - GINT LAB.GDT12/15/17 - - CO\DRAFTING\D17-2-076 Vivid Engineering Group, Inc. BORING NUMBER B-5 1053 Elkton Drive PAGE 1 OF 1 Colorado Springs, CO 80907 Telephone: 719-896-4356 Fax: 719-896-4357 CLIENT AMERCO Real Estate Company PROJECT NAME Proposed New U-Haul Facility PROJECT NUMBER D17-2-076 PROJECT LOCATION NE Corner of I-25 and CR12, Dacono, Colorado DATE STARTED 11/6/17 COMPLETED 11/6/17 GROUND ELEVATION HOLE SIZE 4 inches DRILLING CONTRACTOR Custom Auger (CME-55) GROUND WATER LEVELS: DRILLING METHOD 4" Solid Stem Auger AT TIME OF DRILLING 11.00 ft LOGGED BY S. Noonan CHECKED BY W. Barreire AT END OF DRILLING --- NOTES Middle/North end of lot AFTER DRILLING ---

TESTS MATERIAL DESCRIPTION (ft) LOG BLOW DEPTH COUNTS NUMBER GRAPHIC (N VALUE) SAMPLE TYPE SAMPLE 0 0.5 Topsoil and Grass - 6-inches Sandy Lean CLAY, some thin sand lenses, brown, very moist to wet, very soft to firm GB MC = 24.6%

MC 5-5 MC = 24.9% 5 DD = 103.3 pcf

MC 2-4 MC = 23.7% 10 DD = 96.9 pcf

15 MC 6-9

16.0 SANDSTONE, tan, moist, hard to very hard

MC 50/5" 19.4 Bottom of borehole at 19.4 feet. GENERALS:\VIVID - PROJECTS\D17-2-076_U-HAUL11:57 BH STD US DACONO,12-11-17.GPJ / TP WELL - GINT LAB.GDT12/15/17 - - CO\DRAFTING\D17-2-076 Vivid Engineering Group, Inc. BORING NUMBER B-6 1053 Elkton Drive PAGE 1 OF 1 Colorado Springs, CO 80907 Telephone: 719-896-4356 Fax: 719-896-4357 CLIENT AMERCO Real Estate Company PROJECT NAME Proposed New U-Haul Facility PROJECT NUMBER D17-2-076 PROJECT LOCATION NE Corner of I-25 and CR12, Dacono, Colorado DATE STARTED 11/6/17 COMPLETED 11/6/17 GROUND ELEVATION HOLE SIZE 4 inches DRILLING CONTRACTOR Custom Auger (CME-55) GROUND WATER LEVELS: DRILLING METHOD 4" Solid Stem Auger AT TIME OF DRILLING 10.00 ft LOGGED BY S. Noonan CHECKED BY W. Barreire AT END OF DRILLING --- NOTES Northwest corner of lot AFTER DRILLING ---

TESTS MATERIAL DESCRIPTION (ft) LOG BLOW DEPTH COUNTS NUMBER GRAPHIC (N VALUE) SAMPLE TYPE SAMPLE 0 0.5 Topsoil and Grass - 6-inches Sandy Lean CLAY, brown, moist to wet, very soft to soft GB MC = 15.8%

MC 4-6 MC = 17.0% 5 DD = 110.4 pcf

MC 2-4 MC = 24.8% 10 DD = 100.7 pcf Fines = 70.0%

13.0 Weathered SANDSTONE, tan, moist, medium hard

15 MC 16-21

17.0 SANDSTONE, tan, moist, hard to very hard

MC 50/5" 20

MC 50 24.5 Bottom of borehole at 24.5 feet. GENERALS:\VIVID - PROJECTS\D17-2-076_U-HAUL11:57 BH STD US DACONO,12-11-17.GPJ / TP WELL - GINT LAB.GDT12/15/17 - - CO\DRAFTING\D17-2-076

Appendix B

Geotechnical Laboratory Test Results Vivid Engineering Group, Inc. SUMMARY OF LABORATORY RESULTS 1053 Elkton Drive PAGE 1 OF 1 Colorado Springs, CO 80907 Telephone: 719-896-4356 Fax: 719-896-4357 CLIENT AMERCO Real Estate Company PROJECT NAME Proposed New U-Haul Facility PROJECT NUMBER D17-2-076 PROJECT LOCATION NE Corner of I-25 and CR12, Dacono, Colorado Maximum Water Dry Satur- Liquid Plastic Plasticity %<#200 Class- Void DepthBorehole Size Content Density ation Limit Limit Index Sieve ification Ratio (mm) (%) (pcf) (%) B-1 2.0 24.4 B-1 4.0 28 18 10 20.4 104.8 B-1 14.0 0.075 67 17.4 114.9 B-2 2.0 15.9 B-2 9.0 26.3 95.2 B-3 2.0 14.6 B-3 9.0 0.075 63 22.2 105.9 B-3 14.0 31 15 16 16.1 B-4 2.0 27.8 B-4 4.0 0.075 59 15.6 B-4 9.0 30 11 19 21.9 136.4 B-5 2.0 24.6 B-5 4.0 24.9 103.3 B-5 9.0 23.7 96.9 B-6 2.0 15.8 B-6 4.0 17.0 110.4 B-6 9.0 0.075 70 24.8 100.7 LAB SUMMARY - GINT STD US LAB.GDT - 12/14/17 09:24 - S:\VIVIDLAB - PROJECTS\D17-2-076_U-HAUL SUMMARY09:24 DACONO, 12-11-17.GPJ STD US LAB.GDT 12/14/17 - - GINT CO\DRAFTING\D17-2-076 - Vivid Engineering Group, Inc. ATTERBERG LIMITS' RESULTS 1053 Elkton Drive Colorado Springs, CO 80907 Telephone: 719-896-4356 Fax: 719-896-4357 CLIENT AMERCO Real Estate Company PROJECT NAME Proposed New U-Haul Facility PROJECT NUMBER D17-2-076 PROJECT LOCATION NE Corner of I-25 and CR12, Dacono, Colorado 60 CL CH

50 P L A S 40 T I C I T 30 Y

I N 20 D E X 10

CL-ML ML MH 0 0 20 40 60 80 100 LIQUID LIMIT BOREHOLE DEPTH LL PL PI Fines Classification B-1 4.0 28 18 10 B-3 14.0 31 15 16 B-4 9.0 30 11 19 ATTERBERG LIMITS - GINT STD US LAB.GDT - 12/14/17 09:24 - S:\VIVID - PROJECTS\D17-2-076_U-HAUL09:24 ATTERBERG DACONO,12-11-17.GPJ GINT STD US LAB.GDT 12/14/17 - - LIMITS CO\DRAFTING\D17-2-076 -

Appendix C

Analytical Laboratory Test Results

Appendix D Important Information about This Geotechnical-Engineering Report

Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes.

While you cannot eliminate all such risks, you can manage them. The following information is provided to help.

The Geoprofessional Business Association (GBA) Typical changes that could erode the reliability of this report include has prepared this advisory to help you – assumedly those that affect: a client representative – interpret and apply this • the site’s size or shape; geotechnical-engineering report as effectively • the function of the proposed structure, as when it’s as possible. In that way, clients can benefit from changed from a parking garage to an office building, or from a light-industrial plant to a refrigerated warehouse; a lowered exposure to the subsurface problems • the elevation, configuration, location, orientation, or that, for decades, have been a principal cause of weight of the proposed structure; construction delays, cost overruns, claims, and • the composition of the design team; or disputes. If you have questions or want more • project ownership. information about any of the issues discussed below, contact your GBA-member geotechnical engineer. As a general rule, always inform your geotechnical engineer of project Active involvement in the Geoprofessional Business changes – even minor ones – and request an assessment of their Association exposes geotechnical engineers to a impact. The geotechnical engineer who prepared this report cannot accept wide array of risk-confrontation techniques that can responsibility or liability for problems that arise because the geotechnical be of genuine benefit for everyone involved with a engineer was not informed about developments the engineer otherwise would have considered. construction project. This Report May Not Be Reliable Geotechnical-Engineering Services Are Performed for Do not rely on this report if your geotechnical engineer prepared it: Specific Purposes, Persons, and Projects • for a different client; Geotechnical engineers structure their services to meet the specific • for a different project; needs of their clients. A geotechnical-engineering study conducted • for a different site (that may or may not include all or a for a given civil engineer will not likely meet the needs of a civil- portion of the original site); or works constructor or even a different civil engineer. Because each • before important events occurred at the site or adjacent geotechnical-engineering study is unique, each geotechnical- to it; e.g., man-made events like construction or engineering report is unique, prepared solely for the client. Those who environmental remediation, or natural events like floods, rely on a geotechnical-engineering report prepared for a different client droughts, earthquakes, or groundwater fluctuations. can be seriously misled. No one except authorized client representatives should rely on this geotechnical-engineering report without first Note, too, that it could be unwise to rely on a geotechnical-engineering conferring with the geotechnical engineer who prepared it. And no one report whose reliability may have been affected by the passage of time, – not even you – should apply this report for any purpose or project except because of factors like changed subsurface conditions; new or modified the one originally contemplated. codes, standards, or regulations; or new techniques or tools. If your geotechnical engineer has not indicated an “apply-by” date on the report, Read this Report in Full ask what it should be, and, in general, if you are the least bit uncertain Costly problems have occurred because those relying on a geotechnical about the continued reliability of this report, contact your geotechnical engineering report did not read it in its entirety. Do not rely on an engineer before applying it. A minor amount of additional testing or executive summary. Do not read selected elements only. Read this report analysis – if any is required at all – could prevent major problems. in full. Most of the “Findings” Related in This Report Are You Need to Inform Your Geotechnical Engineer Professional Opinions about Change Before construction begins, geotechnical engineers explore a site’s Your geotechnical engineer considered unique, project-specific factors subsurface through various sampling and testing procedures. when designing the study behind this report and developing the Geotechnical engineers can observe actual subsurface conditions only at confirmation-dependent recommendations the report conveys. A few those specific locations where sampling and testing were performed. The typical factors include: data derived from that sampling and testing were reviewed by your • the client’s goals, objectives, budget, schedule, and geotechnical engineer, who then applied professional judgment to risk-management preferences; form opinions about subsurface conditions throughout the site. Actual • the general nature of the structure involved, its size, sitewide-subsurface conditions may differ – maybe significantly – from configuration, and performance criteria; those indicated in this report. Confront that risk by retaining your • the structure’s location and orientation on the site; and geotechnical engineer to serve on the design team from project start to • other planned or existing site improvements, such as project finish, so the individual can provide informed guidance quickly, retaining walls, access roads, parking lots, and whenever needed. underground utilities. This Report’s Recommendations Are perform their own studies if they want to, and be sure to allow enough Confirmation-Dependent time to permit them to do so. Only then might you be in a position The recommendations included in this report – including any options to give constructors the information available to you, while requiring or alternatives – are confirmation-dependent. In other words,they are them to at least share some of the financial responsibilities stemming not final, because the geotechnical engineer who developed them relied from unanticipated conditions. Conducting prebid and preconstruction heavily on judgment and opinion to do so. Your geotechnical engineer conferences can also be valuable in this respect. can finalize the recommendationsonly after observing actual subsurface conditions revealed during construction. If through observation your Read Responsibility Provisions Closely geotechnical engineer confirms that the conditions assumed to exist Some client representatives, design professionals, and constructors do actually do exist, the recommendations can be relied upon, assuming not realize that geotechnical engineering is far less exact than other no other changes have occurred. The geotechnical engineer who prepared engineering disciplines. That lack of understanding has nurtured this report cannot assume responsibility or liability for confirmation- unrealistic expectations that have resulted in disappointments, delays, dependent recommendations if you fail to retain that engineer to perform cost overruns, claims, and disputes. To confront that risk, geotechnical construction observation. engineers commonly include explanatory provisions in their reports. Sometimes labeled “limitations,” many of these provisions indicate This Report Could Be Misinterpreted where geotechnical engineers’ responsibilities begin and end, to help Other design professionals’ misinterpretation of geotechnical- others recognize their own responsibilities and risks. Read these engineering reports has resulted in costly problems. Confront that risk provisions closely. Ask questions. Your geotechnical engineer should by having your geotechnical engineer serve as a full-time member of the respond fully and frankly. design team, to: • confer with other design-team members, Geoenvironmental Concerns Are Not Covered • help develop specifications, The personnel, equipment, and techniques used to perform an • review pertinent elements of other design professionals’ environmental study – e.g., a “phase-one” or “phase-two” environmental plans and specifications, and site assessment – differ significantly from those used to perform • be on hand quickly whenever geotechnical-engineering a geotechnical-engineering study. For that reason, a geotechnical- guidance is needed. engineering report does not usually relate any environmental findings, conclusions, or recommendations; e.g., about the likelihood of You should also confront the risk of constructors misinterpreting this encountering underground storage tanks or regulated contaminants. report. Do so by retaining your geotechnical engineer to participate in Unanticipated subsurface environmental problems have led to project prebid and preconstruction conferences and to perform construction failures. If you have not yet obtained your own environmental observation. information, ask your geotechnical consultant for risk-management guidance. As a general rule, do not rely on an environmental report Give Constructors a Complete Report and Guidance prepared for a different client, site, or project, or that is more than six Some owners and design professionals mistakenly believe they can shift months old. unanticipated-subsurface-conditions liability to constructors by limiting the information they provide for bid preparation. To help prevent Obtain Professional Assistance to Deal with Moisture the costly, contentious problems this practice has caused, include the Infiltration and Mold complete geotechnical-engineering report, along with any attachments While your geotechnical engineer may have addressed groundwater, or appendices, with your contract documents, but be certain to note water infiltration, or similar issues in this report, none of the engineer’s conspicuously that you’ve included the material for informational services were designed, conducted, or intended to prevent uncontrolled purposes only. To avoid misunderstanding, you may also want to note migration of moisture – including water vapor – from the soil through that “informational purposes” means constructors have no right to rely building slabs and walls and into the building interior, where it can on the interpretations, opinions, conclusions, or recommendations in cause mold growth and material-performance deficiencies. Accordingly, the report, but they may rely on the factual data relative to the specific proper implementation of the geotechnical engineer’s recommendations times, locations, and depths/elevations referenced. Be certain that will not of itself be sufficient to prevent moisture infiltration. Confront constructors know they may learn about specific project requirements, the risk of moisture infiltration by including building-envelope or mold including options selected from the report, only from the design specialists on the design team. Geotechnical engineers are not building- drawings and specifications. Remind constructors that they may envelope or mold specialists.

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