Attch_6_-_Geotech_Rpt_Planetarium.pdf

501113001 L

March 4, 2016 Project No. 501113001

Mr. Lucas Souhrada, PE Merrick & Company Northcreek Office Complex II 5755 Mark Dabling Boulevard, Suite 245 Colorado Springs, Colorado 80919

Subject: Geotechnical Evaluation USAFA Planetarium Chiller Pad 2120 Cadet Drive Colorado Springs, Colorado

Dear Mr. Souhrada:

In accordance with your authorization and our proposal dated December 28, 2015, we have performed a geotechnical evaluation for the proposed chiller pad addition at the United States Air

Force Academy (USAFA) Planetarium located at 2120 Cadet Drive in Colorado Springs, Colorado. The purpose of our evaluation was to assess the subsurface conditions at the project site in order to develop geotechnical recommendations for the chiller pad. This report presents the findings of our subsurface exploration, the results of our laboratory testing, and our geotechnical conclusions and recommendations for the design and construction of this project.

SITE DESCRIPTION

The approximate location of the site is depicted on Figure 1. The proposed area of the new chiller pad is to the north of the existing planetarium in the grass area between the two walkways. The site is bounded by a wooded area to the north, Cadet Drive to the east, and parking lots to the south and west. Rampart Reservoir is located approximately 4.2 miles southwest of the site. Much smaller Reservoir Number Four is located approximately 0.2 miles west of the site.

The existing planetarium building was constructed in 1959. The base of the planetarium is at an elevation of approximately 7,176 feet above mean sea level (MSL), with the main entrance at an

USAFA Planetarium Chiller Addition March 4, 2016 2120 Cadet Drive Project No. 501113001 Colorado Springs, Colorado

501113001 L 2 elevation of approximately 7,180 feet above MSL. The building is supported on a spread footing foundation system. A sloped landscape area (approximately 3:1 [horizontal:vertical]) surrounds the structure. According to our aerial photograph review, the planetarium has existed in its current condition since September of 1999 or earlier.

PROPOSED CONSTRUCTION

The project includes the design and construction of a new chiller pad at the USAFA Planetarium.

The chiller will abut the planetarium along the northern side of the structure adjacent to the existing mechanical room and intake tunnels. The base of the chiller pad is anticipated at an elevation of 7179.5 feet above MSL. The construction of this chiller pad addition will include the design and construction of a concrete retaining wall on the west side of the enclosure.

Based on the original grading plans provided, construction of the chiller pad will require material cuts of up to approximately 10 feet adjacent to the planetarium.

FIELD EXPLORATION AND LABORATORY TESTING

On February 18, 2016, Ninyo & Moore conducted a subsurface exploration at the site to evaluate the existing subsurface conditions and to collect soil samples for laboratory testing. Our evaluation consisted of the drilling, logging, and sampling of two small-diameter borings, Borings B-1 and B-2, using a CME-45 track-mounted drill rig equipped with 4-inch diameter solid flight augers. The borings were drilled to depths of approximately 29.3 feet below ground surface (bgs). The approximate locations of the borings are presented on Figure 2. Disturbed and relatively undisturbed soil samples were collected at selected intervals. Descriptions of the soils encountered are presented on the boring logs in Appendix A.

The soil samples collected were transported to the Ninyo & Moore laboratory for geotechnical laboratory analysis. Selected samples were analyzed to evaluate the in-situ moisture content and dry density, gradation, swell/consolidation potential, direct shear strength, and soil corrosivity characteristics (including pH, resistivity, water soluble sulfates and chlorides). The results of the

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501113001 L 3 in-situ moisture content and dry density tests are presented on the boring logs in Appendix A. A description of each laboratory test method and results are presented in Appendix B.

SUBSURFACE CONDITIONS

The surficial geology of the site vicinity is mapped by Trimble and Machette (1979) as

Pleistocene-age Verdos Alluvium consisting boulders, cobbles, and gravel. The Dawson Arkose is mapped underlying the project area at depth.

Our understanding of the subsurface conditions at the project site is based on our field exploration, laboratory testing, and our experience with the general geology of the area. The subsurface conditions encountered in the borings consisted of approximately 9 to 14 feet of fill underlain by the Dawson Arkose bedrock that extended to boring termination depths of approximately 29.3 feet bgs. The fill generally consisted of reddish brown, moist to wet, clayey sand with varying amounts of gravel. Dawson Arkose bedrock generally consisted of reddish yellow and yellow, moist, weakly to moderately cemented fine to coarse grained conglomerate sandstone.

According to our laboratory testing, selected samples of the fill material had in-place moisture contents between approximately 4.3 and 7.8 percent and in-place dry densities ranging from approximately 104.1 to 125.0 pounds per cubic foot (pcf). We anticipate the fill has been in-place since the original planetarium construction. However, due to the variability of the moisture, dry density, as well as the relatively low blow counts, it is our opinion the fill is not suitable for direct support of new foundations.

Selected samples of the Dawson Arkose bedrock had in-place moisture contents ranging from approximately 5.0 to 6.9 percent and in-place dry densities between approximately 107.3 and

109.5 pcf.

One of the more significant geologic hazards in the Front Range area is the presence of swelling clays in bedrock or surficial deposits. Wetting and drying of bedrock can result in expansion and collapse of those units, which can cause major damage to structures. A review of a Colorado

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Geological Survey map delineating areas based on their relative potential for swelling in the

Denver area by Hart (1973-1974) indicates the soil and bedrock materials in the site vicinity typically have low to moderate swell potential.

Based on the results of our laboratory testing, fill materials encountered in our borings exhibited swell potentials of less than 1.0 percent when inundated against surcharge pressures of approximately 200 pounds per square foot (psf). Based on the results of our subsurface exploration, laboratory testing, and the information obtained from our background review, the on-site fill materials would have a slab performance risk category of “LOW” based on the criteria presented in the following table.

Table 1 - Slab Performance Risk Categories

Slab Performance Risk Category

Representative Percent Swell (500 psf Surcharge)

Representative Percent Swell (1,000 psf Surcharge)

LOW 0 to <3 0 to <2

MODERATE 3 to <5 2 to <4

HIGH 5 to <8 4 to <6

VERY HIGH > 8 > 6

Note: Based on Colorado Association of Geotechnical Engineers (CAGE), Guidelines for Slab Performance Risk Evaluation and Residential Basement Floor System Recommendations (Dawson Metropolitan Area, 1996).

Based on our understanding of the project, it is our opinion that risks associated with vertical post-construction movement due to the Dawson Arkose is low.

Groundwater was not encountered in our borings at the time of drilling. Though not encountered during drilling, groundwater levels can fluctuate due to seasonal variations in precipitation, irrigation, groundwater withdrawal or injection, and other factors. In general, groundwater is not expected to be a constraint to the construction of the project.

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RECOMMENDATIONS

The following sections present our geotechnical recommendations for the design and construction of the proposed chiller pad addition. If the proposed construction is changed from that discussed in this report, Ninyo & Moore should be contacted for additional recommendations.

Excavations: Our evaluation of the excavation characteristics of the on-site materials is based on the results of the subsurface exploration, our site observations, and our experience with similar materials. The on-site surface and near surface soils may generally be excavated with heavy-duty earthmoving or excavation equipment in good operating condition. It should be noted, that while not encountered during our subsurface exploration, the soil in this area may contain cobbles and boulders which could complicate excavation procedures.

The Dawson Arkose bedrock contains layers and lenses of moderately to strongly cemented sandstone bedrock. The excavation rate will be very slow within the formational bedrock and the use of more aggressive excavation techniques, such as single-shank rippers or rock breaking equipment, may be needed to achieve proposed grades.

When nearing excavation bottoms, equipment and procedures that do not cause significant disturbance to excavation bottoms should be used, as feasible. Excavators with buckets having large claws to loosen the soil should be avoided when excavating the bottom 6 to 12 inches of excavations, as such equipment may disturb the excavation base.

Site Grading: Prior to grading, the ground surface in proposed chiller pad area should be cleared of any surface obstructions, debris, topsoil, organics (including vegetation), and other deleterious material.

Materials generated from clearing operations should be removed from the project site for disposal (e.g. at a legal landfill site). Obstructions that extend below finish grade, if present, Colorado Springs, Colorado

501113001 L 6 should be removed and resulting voids filled with compacted, engineered fill or Controlled Low

Strength Material (CLSM).

On-site topsoil should not be incorporated into engineered fill, but may be stockpiled for re-use as landscaping material or other non-structural material. Topsoil contaminated fill materials should not be used during site grading.

Due to the variability of the fill materials encountered at this site, we would typically recommend they be removed from below the proposed chiller footprint. However, due to the elevation of the foundations supporting the planetarium, care should be taken such that excavations for the new structures do not extend below the existing foundations. As a result, excavations for the new structure should not extend below an elevation of 7,176 feet above MSL.

The exposed subgrade materials should be firm and unyielding prior to fill placement. The extent of and depths of fill removal should be evaluated by our representative during the excavation work based on observation of the soils exposed. Additional recommendations specific to the site conditions encountered may be provided at the time of construction.

Some shrinkage should be anticipated when on-site soils are excavated, processed, and compact-

ed. For planning purposes, an estimated shrinkage factor of up to approximately of 5 percent may be used for on-site fill and bedrock.

Fill Placement and Compaction: Engineered fill should be moisture-conditioned to between 2 percent above and 2 percent below optimum moisture content and compacted to a relative compaction of 95 percent of the maximum dry density as evaluated by ASTM D1557.

Fill should be compacted by appropriate mechanical methods. Lift thickness for fill will depend on the type of compaction equipment utilized, but should generally be placed in lifts not exceeding 8 inches in loose thickness. No fill materials should be placed, worked, or rolled while they are frozen, thawing, or during poor/inclement weather conditions.

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Compaction areas should be kept separate, and no lift should be covered by another until relative compaction and moisture content within the recommended ranges are obtained.

According to our laboratory test results, the on-site soils are clayey sands with gravel and varying in-place moisture contents and in-place dry densities. Consequently, it may be difficult to compact these soils at their in-place moisture contents and the addition of water or drying may be needed to adjust the moisture contents prior to compaction.

If surfaces to receive fill expose loose, wet, soft, or otherwise deleterious material, additional material should be excavated or other measures taken to establish a firm platform for filling. The surfaces to receive fill should be stabilized prior to placement of fill.

Temporary Excavations: Appropriate slope inclinations should be evaluated in the field by an

OSHA-qualified “Competent Person” based on the conditions encountered. Based on the results of our subsurface explorations and in accordance with Appendix A to Subpart P of the referenced

Occupational Safety and Health Administration (OSHA) regulations (OSHA, 2005), Type C Soil is appropriate for the project site soils consisting of alluvial deposits. For Type C soil conditions, OSHA recommends a temporary slope inclination of 1.5H:1V or flatter for excavations 20 feet or less in depth. Steeper cut slopes may be utilized for excavations less than 4 feet deep depending on the strength, moisture content, and homogeneity of the soils as observed in the field. If construction materials or stockpiled earth materials are stored, or equipment is operated near the top of construction excavation slopes, flatter slope geometry or shoring should be used during construction.

Earthwork operations should be observed and compaction of engineered fill and backfill materials should be tested by the project’s geotechnical consultant. Additional field tests may also be performed in structural and non-structural areas at the discretion of the geotechnical consultant.

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Construction Vibrations: Due to the proximity of the proposed chiller to the planetarium, excavation activities may generate vibrations which could affect adjacent structures. Vibrations could be amplified and construction affected if boulders, cobbles, and/or resistant bedrock are encountered during excavations.

As a result of the risk for construction vibrations which could affect the planetarium, we recommend that a vibration monitoring plan be prepared and implemented to monitor vibrations generated by construction activities at the site. The monitoring plan should include recommended vibration threshold levels, vibration monitoring frequency, and protocol for stop-work and/or reducing vibration levels. A detailed scope of services and estimated fee for such services can be provided upon request.

Foundations: We anticipate the chiller pad will be supported on either a rigid, reinforced concrete mat foundation or conventional spread footings. Fill materials placed during the original planetarium construction were encountered at this site to depths of approximately 9 to 14 feet bgs, corresponding to elevations of approximately 7,179 to 7,174 feet above MSL. The adjacent existing foundations for the planetarium are at an elevation of approximately 7,176 feet above

MSL. While removal of the fill would typically be recommended, care should be taken such that excavations do not extend below the planetarium foundations. As such, new foundations should be designed to bear on recompacted fill materials extending to an elevation of 7,176 feet above

MSL. The fill or native soils encountered at the base of the excavation should be surficially compacted with hand-held dynamic compaction equipment (i.e., jumping jack) prior to placement of the recompacted fill to the foundation bearing elevation.

Mat foundations bearing on 12 inches or more of compacted engineered fill extending to Dawson

Arkose bedrock may be designed using a coefficient of subgrade reaction, Kv1, of 150 tons per cubic foot (tcf). The coefficient of subgrade reaction for a mat of specific width, Kb, may be evaluated using the following equation:

Kb = Kv1 ( b+1

) 2 2b

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Where b is the least width of the foundation measured in feet.

A net allowable bearing pressure of 3,000 psf may be used for mat foundations or conventional spread footings bearing on compacted engineered fill extending an elevation of 7,176 feet above

MSL or on Dawson Arkose bedrock, whichever is shallower. The allowable soil bearing pressure may be increased by one-third when considering total loads including transient loads such as wind or seismic forces. Footings should extend to 36 inches or more below the adjacent exterior finished grade (for frost protection), and bear on a zone of adequately placed and compacted engineered fill as described above. Continuous footings should have a width of 16 inches or more and isolated footings should have a width of 24 inches or more.

Where feasible, the foundations should be proportioned such that the resultant force from total footing loads, including lateral loads, falls within the kern (i.e., the middle one-third of the footing base). The average footing bearing pressure should not exceed the allowable equivalent uniform bearing pressure presented above; however, peak edge stresses may exceed this value as long as the resultant passes through the middle third of the footing base.

The total and differential settlements corresponding to these allowable bearing loads are estimated to be less than approximately 1-inch and ½-inch, respectively, over a horizontal span of 20 feet.

We anticipate that a Site Class D, according to the 2012 International Building Code classification, will be utilized for seismic foundation design.

Earth Pressures and Foundation Walls: Earth pressures are used to compute the lateral forces acting on below-grade walls. These pressures can be classified as at-rest, active, and passive. The direction and magnitude of the soil/wall movement just before failure affects the resulting pressure condition. At-rest conditions exist when there is no movement, such as for a restrained wall. Active stresses are exerted when the wall moves out and the soil moves toward the wall away from the soil mass, thereby mobilizing the shear strength of the soil. The active pressures are fully mobilized at horizontal movements of about 0.1 percent of the wall height for cohesionless soils, such as sands and gravels. Passive stresses exist when the wall moves toward

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501113001 L 10 the soil mass. Movement typically needed to mobilize passive pressures greatly exceeds that needed to mobilize active pressures. The passive pressures are, therefore, rarely fully mobilized and are often overestimated when used to compute resistance forces.

The recommended equivalent fluid pressures in Table 2 may be appropriate for the design of the below grade walls.

Table 2 - Lateral Earth (Equivalent Fluid) Pressures

Soil Condition

Active Pressure (pcf)

At-rest Pressure (pcf)

Passive Pressure (pcf)

On-Site Soils 35 50 440

The use of heavy compaction equipment adjacent to retaining walls could result in lateral earth pressures well in excess of those predicted in Table 2. We recommend that the upper 24 inches of soil that is not protected by pavement or a concrete slab, be neglected when calculating passive resistance. This zone, where applicable, should be backfilled with cohesive soils to minimize infiltration of surface water into the backfill. For frictional resistance to lateral loads, we recommend that an ultimate coefficient of friction of 0.35 be used between soil and concrete.

Measures should be taken so that moisture does not build up behind retaining walls. Retaining walls should be provided with a drain. Back drainage measures should include free-draining backfill material and perforated drainpipes or weepholes. Drainpipes should outlet away from structures, and retaining walls should be waterproofed in accordance with the recommendations of the project civil engineer or architect. In lieu of the wrapped open-graded gravel, a geocompo-site drainage mat attached to the wall and discharging into the drain pipe or weep holes may be considered. To reduce the potential for water- and sulfate/salt-related damage to the retaining walls, particular care should be taken in the selection of the appropriate type of waterproofing material to be utilized and in the application of this material.

Below-grade walls should be damp proofed or waterproofed in accordance with the recommendations of the project Architect and Structural Engineer. Design considerations should be given to prevention of efflorescent development on the below-grade concrete.

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Concrete: Laboratory tests performed on a selected sample of on-site soils indicated a negligible sulfate exposure to concrete. Notwithstanding the sulfate test results, due to the limited number of tests performed, as well as our experience with similar soil conditions at nearby projects, we recommend the use of Type I/II cement for construction of concrete structures at this site. Due to uncertainties such as the potential use of reclaimed irrigation water or topsoil that may contain higher sulfate contents, pozzolan or admixtures designed to increase sulfate resistance may be considered.

The concrete should have a water-cement ratio of no more than 0.50 by weight for normal weight aggregate concrete. The structural engineer should select the concrete design strength based on the project specific loading conditions. However, higher strength concrete may be selected for increased durability and resistance to slab curling and shrinkage cracking. We recommend the use of concrete with a design 28-day compressive strength of 4,000 psi or more. Concrete exposed to the elements should be air-entrained.

Corrosivity: The corrosion potential of the on-site materials was analyzed to evaluate its poten-tial effects on buried metals. Corrosion potential was evaluated using the results of laboratory testing of samples obtained during the subsurface evaluation that were considered representative of soils at the subject site.

The results of the laboratory testing indicate the on-site materials have moderate resistivity and could potentially be moderately corrosive to ferrous metals. Therefore, special consideration should be given to the use of heavy gauge, corrosion protected, underground steel pipe or cul-verts, if any are planned. As an alternative, plastic pipe or reinforced concrete pipe could be considered. A corrosion specialist should be consulted for further recommendations.

Scaling: Climatic conditions in the project area including relatively low humidity, large temperature changes and repeated freeze-thaw cycles, may cause surficial scaling and spalling of exterior concrete. Occurrence of surficial scaling and spalling can be aggravated by poor

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501113001 L 12 workmanship during construction, such as “over-finishing” concrete surfaces and the use of de-icing salts on exterior concrete flatwork, particularly during the first winter after construction.

The measures below can be beneficial for reducing the concrete scaling. However, because of the other factors involved, including workmanship, surface damage to concrete can develop even though the measures provided below were followed. The mix design criteria should be coordinated with other project requirements including the criteria for soluble sulfate resistance presented in this report.

Curing concrete in accordance with applicable codes and guidelines.

Maintaining a water/cement ratio of 0.45 by weight for exterior concrete mixes.

Including Type F fly ash in exterior concrete mixes as 20 percent of the cementitious material.

Specifying a 28-day, compressive strength of 4,200 or more psi for exterior concrete that may be exposed to de-icing salts.

Avoiding the use of de-icing salts through the first winter after construction.

Frost Heave: Site soils are susceptible to frost heave if allowed to become saturated and exposed to freezing temperatures and repeated freeze/thaw cycling. The formation of ice in the underlying soils can result in 2 or more inches of heave of pavements, flatwork and other hardscaping in sustained cold weather. A portion of this movement may be recovered when the soils thaw, but due to loss of soil density some degree of displacement will remain. Frost heave of hardscaping could also result in areas where the subgrade soils were placed on engineered fill.

In areas where hardscape movements are a design concern, replacement of the subgrade soils with 2 or more feet of clean, coarse sand or gravel, or supporting the element on foundations similar to the building, or spanning over a void should be considered. Detailed recommendations in this regard can be provided upon request.

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Construction in Cold or Wet Weather: Earthwork activities undertaken during the cold weather season may be difficult and should be done by an experienced contractor. Fill should not be placed on top of frozen soils. The frozen soils should be removed prior to the placement of new engineered fill or other construction material. Frozen soil should not be used as structural fill or backfill. The frozen soil may be reused (provided it meets the selection criteria) once it has thawed completely. In addition, compaction of the soils may be more difficult due to the viscosity change in water at lower temperatures.

If construction proceeds during cold weather, foundations, slabs, or other concrete elements should not be placed on frozen subgrade soil. Frozen soil should either be removed from beneath concrete elements, or thawed and recompacted. To limit the potential for soil freezing, the time passing between excavation and construction should be minimized. Blankets, straw, soil cover, or heating could be used to discourage the soil from freezing.

Site Drainage: Infiltration of water into subsurface soils can lead to soil movement and associated distress, and chemically and physically related deterioration of concrete and masonry structures. To reduce the potential for infiltration of moisture into subsurface soils at the site, we recommend the following:

Positive drainage should be established and maintained away from the proposed chiller pad.

Positive drainage may be established by providing a surface gradient for paved areas of 2 to 5 percent or more for a distance of 10 feet or more away from structures. For unpaved areas, positive drainage may be established by a slope of 5 to 10 percent for 10 feet or more away from structures, where possible.

Adequate surface drainage should be provided to channel surface water away from on-site structures and off paved surfaces to a suitable outlet such as a storm drain. Adequate surface drainage may be enhanced by utilization of graded swales, area drains, and other drainage devices. Surface run-off should not be allowed to pond near structures or structure footings.

Building roof drains, if any, should have downspouts tightlined to an appropriate outlet, such as a storm drain or the street, away from structures, pavements, and flatwork. If tightlining of the downspouts is not practicable, they should discharge 5 feet or more away from structures and onto surfaces that slope away from the structure. Downspouts should not be allowed to discharge onto the ground surface adjacent to building foundations.

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The possibility of moisture infiltration beneath a structure, in the event of plumbing leaks, should be considered in the design and construction of underground water and sewer con-duits. Permitting increases in moisture to the building supporting soils may result in a decrease in bearing capacity and an increase in settlement, heave, and/or differential move-ment. Incorporating a perimeter drainage system around the building foundations that will aid in reduction of the moisture infiltration of subsurface soils may be considered.

Utility trenches should be backfilled with compacted, low permeability fill (i.e. permeability of 5-10 cm/s or less) within 5 feet of the building. Planters, if any, should be maintained 5 feet or more from the building and constructed with closed bottoms or with drainage sys-tems to drain excess irrigation away from the building.

Pre-Construction Conference: We recommend that a pre-construction conference be held.

Representatives of the owner, civil engineer, the geotechnical consultant, and the contractor should be in attendance to discuss the project plans and schedule. Our office should be notified if the project description included herein is incorrect, or if the project characteristics are significantly changed.

Construction Observation and Testing: A qualified geotechnical consultant should perform appropriate observation and testing services during grading and construction operations. These services should include observation of any soft, loose, or otherwise unsuitable soils, evaluation of subgrade conditions where soil removals are performed, evaluation of the suitability of pro-posed borrow materials for use as fill, evaluation of the stability of open temporary excavations, evaluation of the results of any subgrade stabilization or dewatering activities, and performance of observation and testing services during placement and compaction of engineered fill and back-fill soils.

The geotechnical consultant should also perform observation and testing services during place-ment of concrete, mortar, grout, asphalt concrete, and steel reinforcement. If another geotechnical consultant is selected to perform observation and testing services for the project, we request that the selected consultant provide a letter to the owner, with a copy to Ninyo & Moore, indicating that they fully understand our recommendations and they are in full agreement with the recommendations contained in this report. Qualified subcontractors utilizing appropriate

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LIMITATIONS

The field evaluation, laboratory testing, and geotechnical analyses presented in this geotechnical report have been conducted in general accordance with current practice and the standard of care exercised by geotechnical consultants performing similar tasks in the project area. No warranty expressed or implied, is made regarding the conclusions, recommendations, and opinions presented in this report. There is no evaluation detailed enough to reveal every subsurface condition. Variations may exist and conditions not observed or described in this report may be encountered during construction. Uncertainties relative to subsurface conditions can be reduced through additional subsurface exploration. Additional subsurface evaluation will be performed upon request. Please also note that our evaluation was limited to assessment of the geotechnical aspects of the project, and did not include evaluation of structural issues, environmental concerns, or the presence of hazardous materials.

This document is intended to be used only in its entirety. No portion of the document, by itself, is designed to completely represent any aspect of the project described herein. Ninyo & Moore should be contacted if the reader requires additional inArkose or has questions regarding the content, interpretations presented, or completeness of this document.

This report is intended for design purposes only. It does not provide sufficient data to prepare an accurate bid by contractors. It is suggested that the bidders and their geotechnical consultant perform an independent evaluation of the subsurface conditions in the project areas. The independent evaluations may include, but not be limited to, review of other geotechnical reports prepared for the adjacent areas, site reconnaissance, and additional exploration and laboratory testing.

Our conclusions, recommendations, and opinions are based on an analysis of the observed site conditions. If geotechnical conditions different from those described in this report are

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3/4/16 encountered, our office should be notified and additional recommendations, if warranted, will be provided upon request. It should be understood that the conditions of a site could change with time as a result of natural processes or the activities of man at the subject site or nearby sites. In addition, changes to the applicable laws, regulations, codes, and standards of practice may occur due to government action or the broadening of knowledge. The findings of this report may, therefore, be invalidated over time, in part or in whole, by changes over which Ninyo & Moore has no control.

This report is intended exclusively for use by the client. Any use or reuse of the findings, conclusions, and/or recommendations of this report by parties other than the client is undertaken at said parties’ sole risk.

Respectfully submitted, NINYO & MOORE

Kelley Lange, EI Staff Engineer

Brian F. Gisi, PE Principal Engineer

KL/BFG

Attachments: Figure 1 – Site Location Figure 2 – Boring Locations Appendix A – Boring Logs Appendix B – Laboratory Testing

Distribution: (1) Addressee (via email)

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REFERENCES

American Concrete Institute, 2004, Guidelines for Concrete Floor and Slab Construction (ACI 302.1R-04).

American Concrete Institute, 2008, Building Code Requirements for Structural Concrete (ACI 318-08) and Commentary.

American Society for Testing and Materials (ASTM), 2010 Annual Book of ASTM Standards.

Department of the Air Force, 1957, United States Air Force Academy Museum (Planetarium), Sheets 1 through 12, dated August 20

International Code Council (ICC), 2015, International Building Code (IBC).

Ninyo & Moore, In-house proprietary information.

Occupational Safety and Health Administration (OSHA), 2005, OSHA Standards for the Construction Industry, 29 CFR Part 1926: dated June.

Trimble, Donald E. and Machette, Michael M., 1979, Geologic Map of the Colorado Springs – Castle Rock Area, Front Range Urban Corridor, Colorado: United States Geological Survey.

Tweto, Ogden, 1979, Geologic Map of Colorado, United States Geological Survey and Colorado Geologic Survey.

SITE LOCATION

FIGURE

Ap p ro x i ma te Sca l e :

1 i n ch = 19 0 0 f e e t

Note: Dimensions, directions, and locations are approximate.

DATE:

3/16 file no: 1113vmap0216

PROJECT NO:

501113001

USAFA PLANETARIUM CHILLER ADDITION

2120 CADET DRIVE

COLORADO SPRINGS, COLORADO

Source: MacVan, Colorado Springs Edition, 2010.

N

APPROXIMATE

SITE LOCATION

fil e n o :1 b lm

Note: Dimensions, directions, and locations are approximate.

FIGURE

2DATE:

3/16

PROJECT NO:

501113001

USAFA PLANETARIUM CHILLER ADDITION

2120 CADET DRIVE

COLORADO SPRINGS, COLORADO

BORING LOCATIONS

Ap p ro x i ma te Sca l e :

1 i n ch = 30 f e e t

N

Source: United States Air Force, 11/03/01.

COAL CREEK CANYON ROAD

B-1 B-2

LEGEND

Boring LocationB-2

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APPENDIX A

BORING LOGS

Field Procedure for the Collection of Disturbed Samples Disturbed soil samples were obtained in the field using the following methods.

Bulk Samples Bulk samples of representative earth materials were obtained from the exploratory borings.

The samples were bagged and transported to the laboratory for testing.

Field Procedure for the Collection of Relatively Undisturbed Samples Relatively undisturbed soil samples were obtained in the field using the following methods.

The California Drive Sampler The sampler, with an external diameter of 2.4 inches, was lined with four, 4-inch long, thin brass rings with inside diameters of approximately 1.9 inches. The sample barrel was driven into the ground with the weight of a hammer in general accordance with ASTM D3550. The driving weight was permitted to fall freely. The approximate length of the fall, the weight of the hammer, and the number of blows per foot of driving are presented on the boring logs as an index to the relative resistance of the materials sampled. The samples were removed from the sample barrel in the brass liners, sealed, and transported to the laboratory for testing.

SOIL CLASSIFICATION CHART PER ASTM D 2488

PRIMARY DIVISIONS

SECONDARY DIVISIONS

GROUP SYMBOL GROUP NAME

COARSE-

GRAINED

SOILS

more than

50% retained on No. 200 sieve

GRAVEL

more than

50% of coarse fraction retained on No. 4 sieve

CLEAN GRAVEL

less than 5% fines

GW well-graded GRAVEL

GP poorly graded GRAVEL

GRAVEL with

DUAL

CLASSIFICATIONS

5% to 12% fines

GW-GM well-graded GRAVEL with silt

GP-GM poorly graded GRAVEL with silt

GW-GC well-graded GRAVEL with clay

GP-GC poorly graded GRAVEL with clay

GRAVEL with

FINES

more than 12% fines

GM silty GRAVEL

GC clayey GRAVEL

GC-GM silty, clayey GRAVEL

SAND

50% or more of coarse fraction passes

No. 4 sieve

CLEAN SAND

less than 5% fines

SW well-graded SAND

SP poorly graded SAND

SAND with

DUAL

CLASSIFICATIONS

5% to 12% fines

SW-SM well-graded SAND with silt

SP-SM poorly graded SAND with silt

SW-SC well-graded SAND with clay

SP-SC poorly graded SAND with clay

SAND with FINES more than 12% fines

SM silty SAND

SC clayey SAND

SC-SM silty, clayey SAND

FINE-

GRAINED

SOILS

50% or more passes No. 200 sieve

SILT and

CLAY

liquid limit less than 50%

INORGANIC

CL lean CLAY

ML SILT

CL-ML silty CLAY

ORGANIC

OL (PI > 4) organic CLAY

OL (PI < 4) organic SILT

SILT and

CLAY

liquid limit 50% or more

INORGANIC

CH fat CLAY

MH elastic SILT

ORGANIC

OH (plots on or above “A”-line) organic CLAY

OH (plots below “A”-line) organic SILT

Highly Organic Soils PT Peat

USCS METHOD OF SOIL CLASSIFICATION

Explanation of USCS Method of Soil Classification

PROJECT NO. DATE FIGURE

APPARENT DENSITY - COARSE-GRAINED SOIL

APPARENT

DENSITY

SPOOLING CABLE OR CATHEAD AUTOMATIC TRIP HAMMER

SPT

(blows/foot)

MODIFIED

SPLIT BARREL

(blows/foot)

SPT

(blows/foot)

MODIFIED

SPLIT BARREL

(blows/foot)

Very Loose < 4 < 8 < 3 < 5

Loose 5 - 10 9 - 21 4 - 7 6 - 14

Medium Dense 11 - 30 22 - 63 8 - 20 15 - 42

Dense 31 - 50 64 - 105 21 - 33 43 - 70

Very Dense > 50 > 105 > 33 > 70

CONSISTENCY - FINE-GRAINED SOIL

CONSIS-

TENCY

SPOOLING CABLE OR CATHEAD AUTOMATIC TRIP HAMMER

SPT

(blows/foot)

MODIFIED

SPLIT BARREL

(blows/foot)

SPT

(blows/foot)

MODIFIED

SPLIT BARREL

(blows/foot)

Very Soft < 2 < 3 < 1 < 2

Soft 2 - 4 3 - 5 1 - 3 2 - 3

Firm 5 - 8 6 - 10 4 - 5 4 - 6

Stiff 9 - 15 11 - 20 6 - 10 7 - 13

Very Stiff 16 - 30 21 - 39 11 - 20 14 - 26

Hard > 30 > 39 > 20 > 26

LIQUID LIMIT (LL), %

P

LA

S

TI

C

IT

Y

IN

D E

X

P I)

0 10

20 30 40 50 60 70 80 90 100

MH or OH

ML or OLCL - ML

PLASTICITY CHART

GRAIN SIZE

DESCRIPTION SIEVE

SIZE

GRAIN

SIZE

APPROXIMATE

SIZE

Boulders > 12” > 12” Larger than basketball-sized

Cobbles 3 - 12” 3 - 12” Fist-sized to basketball-sized

Gravel

Coarse 3/4 - 3” 3/4 - 3” Thumb-sized to fist-sized

Fine #4 - 3/4” 0.19 - 0.75” Pea-sized to thumb-sized

Sand

Coarse #10 - #4 0.079 - 0.19” Rock-salt-sized to pea-sized

Medium #40 - #10 0.017 - 0.079” Sugar-sized to rock-salt-sized

Fine #200 - #40 0.0029 - 0.017”

Flour-sized to sugar-sized

Fines Passing #200 < 0.0029” Flour-sized and smaller

CH or OH

CL or OL

BORING LOG EXPLANATION SHEET

XX/XX

Bulk sample.

Modified split-barrel drive sampler.

2-inch inner diameter split-barrel drive sampler.

No recovery with modified split-barrel drive sampler, or 2-inch inner diameter split-barrel drive sampler.

Sample retained by others.

Standard Penetration Test (SPT).

No recovery with a SPT.

Shelby tube sample. Distance pushed in inches/length of sample recovered in inches.

No recovery with Shelby tube sampler.

Continuous Push Sample.

Seepage.

Groundwater encountered during drilling.

Groundwater measured after drilling.

SM MAJOR MATERIAL TYPE (SOIL):

Solid line denotes unit change.

CL Dashed line denotes material change.

Attitudes: Strike/Dip b: Bedding c: Contact j: Joint f: Fracture F: Fault cs: Clay Seam s: Shear bss: Basal Slide Surface sf: Shear Fracture sz: Shear Zone sbs: Shear Bedding Surface

The total depth line is a solid line that is drawn at the bottom of the boring.

BORING LOG

Explanation of Boring Log Symbols

PROJECT NO. DATE FIGURE

D E

P T

H (f e e t)

B L O

W S

/F O

O T

M O

IS

T

U R

E

D R

Y D

E N

S

IT

Y (P

C F

C

LA

S S

IF

IC

A T

IO

N

U

.S .C

.S

50/6"

50/5"

50/4"

50/4"

50/2"

6.1

4.3

5.1

118.4

113.0

109.5

FILL:

Reddish brown, moist, clayey SAND with gravel.

DAWSON FORMATION:

Reddish yellow, moist, moderately cemented, fine- to coarse-grained CONGLOMERATE SANDSTONE; weathered.

Total depth = 29.2 feet.

Groundwater not encountered during drilling.

Backfilled with on site soil immediately after drilled.

Notes:

Groundwater, though not encountered at the time of drilling, may rise to a higher level due to seasonal variations in precipitation and several other factors as discussed in the report.

The ground elevation shown above is an estimation only. It is based on our interpretations of published maps and other documents reviewed for the purposes of this evaluation. It is not sufficiently accurate for preparing construction bids and design documents.

BORING LOG

USAFA PLANETARIUM CHILLER ADDITION

2120 CADET DRIVE, COLORADO SPRINGS, COLORADO

PROJECT NO.

501113001

DATE

3/16

FIGURE

A-1

D E

P T

H fe e t)

B u lk S

A M

P L

E S

D ri ve n

B L

O W

S /F

O O

T

M O

IS

T

U R

E

D R

Y D

E N

S

IT

Y

P C

F

S Y

M B

O L

C L

A S

S

IF

IC

A

T

IO

N U

.S .C

.S

DESCRIPTION/INTERPRETATION

DATE DRILLED 2/18/2016 BORING NO. B-1

GROUND ELEVATION 7,188'±(MSL) SHEET 1 OF

METHOD OF DRILLING CME 45, 4" Solid Stem Auger, (Vine Laboratories)

DRIVE WEIGHT 140 lbs. (Auto Hammer) DROP 30"

SAMPLED BY DLH LOGGED BY DLH REVIEWED BY BFG

50/9"

50/4"

50/3"

50/3"

5.8

7.8

5.2

6.9

5.0

125.0

104.1

107.3

FILL:

Reddish brown, wet, clayey SAND with gravel.

Moist.

DAWSON FORMATION:

Yellow, moist, weakly cemented, clayey fine- to coarse-grained CONGLOMERATE SANDSTONE; weathered.

Total depth = 29.3 feet.

Groundwater was not encountered during drilling.

Backfilled with on site soil immediately after drilled.

Notes:

Groundwater, though not encountered at the time of drilling, may rise to a higher level due to seasonal variations in precipitation and several other factors as discussed in the report.

The ground elevation shown above is an estimation only. It is based on our interpretations of published maps and other documents reviewed for the purposes of this evaluation. It is not sufficiently accurate for preparing construction bids and design documents.

BORING LOG

USAFA PLANETARIUM CHILLER ADDITION

2120 CADET DRIVE, COLORADO SPRINGS, COLORADO

PROJECT NO.

501113001

DATE

3/16

FIGURE

A-2

D E

P T

H fe e t)

B u lk S

A M

P L

E S

D ri ve n

B L

O W

S /F

O O

T

M O

IS

T

U R

E

D R

Y D

E N

S

IT

Y

P C

F

S Y

M B

O L

C L

A S

S

IF

IC

A

T

IO

N U

.S .C

.S

DESCRIPTION/INTERPRETATION

DATE DRILLED 2/18/2016 BORING NO. B-2

GROUND ELEVATION 7,188'±(MSL) SHEET 1 OF

METHOD OF DRILLING CME 45, 4" Solid Stem Auger, (Vine Laboratories)

DRIVE WEIGHT 140 lbs. (Auto Hammer) DROP 30"

SAMPLED BY DLH LOGGED BY DLH REVIEWED BY BFG

Colorado Springs, Colorado

501113001 L

APPENDIX B

LABORATORY TESTING

Classification Soils were visually and texturally classified in accordance with the Unified Soil Classification System (USCS) in general accordance with ASTM D2488. Soil classifications are indicated on the logs of the exploratory borings in Appendix A.

In-Place Moisture and Density Tests The moisture content and dry density of relatively undisturbed samples obtained from the exploratory borings were evaluated in general accordance with ASTM D2937 and ASTM D2216.

The test results are presented on the boring logs in Appendix A.

Atterberg Limits Tests were performed on selected representative fine-grained soil samples to evaluate the liquid limit, plastic limit, and plasticity index in general accordance with ASTM D 4318. These test re-sults were utilized to evaluate the soil classification in accordance with the Unified Soil Classification System (USCS). The test results and classifications are shown on Figure B-1.

Gradation Analysis Gradation analysis tests were performed on selected representative soil samples in general ac-cordance with ASTM D 422. The grain-size distribution curves are shown on Figures B-2 through B-5. These test results were utilized in evaluating the soil classifications in accordance with the USCS.

Consolidation/Swell Tests The consolidation and/or swell potential of selected materials were evaluated in general accordance with ASTM D4546. Specimens were loaded with a specified surcharge before inundation with water. Readings of volumetric consolidation/swell were recorded until completion of primary consolidation/swell. After the completion of primary swell, surcharge loads were increased incrementally to evaluate swell pressure. The results of the consolidation/swell tests are presented on Figures B-6 and B-7.

Soil Corrosivity Tests Soil pH and resistivity tests were performed on representative samples in general accordance with ASTM D 4972 and AASHTO T288, respectively. The soluble sulfate of a selected sample was evaluated in general accordance with CDOT Test Method CP-L 2103. The chloride content of a selected sample was evaluated in general accordance with CDOT Test Method CP-L 2104.

The test results are presented on Figure B-8.

Direct Shear Tests Direct shear tests were performed on relatively undisturbed samples in general accordance with ASTM D 3080 to evaluate the shear strength characteristics of selected materials. The samples were inundated during shearing to represent adverse field conditions. The results are shown on Figure B-9.

LOCATION

NP - INDICATES NON-PLASTIC

PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 4318

USAFA PLANETARIUM CHILLER ADDITION

2120 CADET DRIVE

COLORADO SPRINGS, COLORADO

SC

SC

CL

CL94.0-5.5

No. 40 Sieve)

SYMBOL

2.0-3.5 1023

(FT)

DEPTH

13B-1

CLASSIFICATION

INDEX, PI

LIQUID PLASTIC PLASTICITY

LIMIT, LL

14B-2

501113001 3/16 B-1

USCS

USCS

(Entire Sample)(Fraction Finer ThanLIMIT, PL

CH or OH

CL or OL MH or OH

ML or OL CL - ML

0 10 20 30 40 50 60 70 80 90 100

P

LA

ST

IC

IT

Y

IN

D

EX

, P

I

LIQUID LIMIT, LL

ATTERBERG LIMITS TEST RESULTS

PROJECT NO. DATE

Coarse Fine Coarse Medium SILT CLAY

3" 2" 3/4" 4 10 30 50

PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 422

501113001 3/16 B-2

USAFA PLANETARIUM CHILLER ADDITION

2120 CADET DRIVE

COLORADO SPRINGS, COLORADO

Fine

Sample Location

D10

16 2003/8"

GRAVEL SAND FINES

Symbol Plasticity

Index Plastic Limit

Liquid Limit

1-1/2" 1"

Depth (ft)

D30

10 -- --

D60

B-1 2.0-3.5 23 13

Passing No. 200

CcCu USCS

SC-- -- -- 15

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.00010.0010.010.1110100

P E

R C

E N

T F

IN

E

R B

Y W

E

IG

H T

GRAIN SIZE IN MILLIMETERS

U.S. STANDARD SIEVE NUMBERS HYDROMETER

GRADATION TEST RESULTS

PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 422

Passing No. 200

CcCu USCS

SC-- -- -- 13-- -- --

D60

B-1 14.0-14.5 -- --

GRAVEL SAND FINES

Symbol Plasticity

Index Plastic Limit

Liquid Limit

1-1/2" 1"

Depth (ft)

D30

Fine

Sample Location

D10

16 2003/8"

501113001 3/16 B-3

USAFA PLANETARIUM CHILLER ADDITION

2120 CADET DRIVE

COLORADO SPRINGS, COLORADO

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.00010.0010.010.1110100

P E

R C

E N

T F

IN

E

R B

Y W

E

IG

GRADATION TEST RESULTS

PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 422

501113001 3/16 B-4

USAFA PLANETARIUM CHILLER ADDITION

2120 CADET DRIVE ADDITION

COLORADO SPRINGS, COLORADO

Fine

Sample Location

D10

16 2003/8"

GRAVEL SAND FINES

Symbol Plasticity

Index Plastic Limit

Liquid Limit

1-1/2" 1"

Depth (ft)

D30

9 -- --

D60

B-2 4.0-5.5 23 14

Passing No. 200

CcCu USCS

SC-- -- -- 18

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.00010.0010.010.1110100

P E

R C

E N

T F

IN

E

R B

Y W

E

IG

GRADATION TEST RESULTS

PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 422

Passing No. 200

CcCu USCS

SC-- -- -- 28-- -- --

D60

B-2 24.0-24.2 -- --

GRAVEL SAND FINES

Symbol Plasticity

Index Plastic Limit

Liquid Limit

1-1/2" 1"

Depth (ft)

D30

Fine

Sample Location

D10

16 2003/8"

501113001 3/16 B-5

USAFA PLANETARIUM CHILLER ADDITION

2120 CADET DRIVE

COLORADO SPRINGS, COLORADO

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.00010.0010.010.1110100

P E

R C

E N

T F

IN

E

R B

Y W

E

IG

GRADATION TEST RESULTS

Seating Cycle Sample Location B-1 Loading Prior to Inundation Depth (ft.) 2.0-3.5 Loading After Inundation Soil Type SC Rebound Cycle

PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 4546

501113001

USAFA PLANETARIUM CHILLER ADDITION

2120 CADET DRIVE

COLORADO SPRINGS, COLORADO

B-6

3/16

-1.0

1.0

0.1 1.0 10.0 100.0

C O

N S

O

LI

D A

T

IO

N

IN

P E

R C

E N

T O

F S

A M

P

LE

T H

IC

K

N E

S S

E

G A

T

IV

E

IN

D

IC

A T

E S

E X

P A

N S

IO

N

STRESS IN KIPS PER SQUARE FOOT

CONSOLIDATION/SWELL TEST RESULTS

Seating Cycle Sample Location B-2 Loading Prior to Inundation Depth (ft.) 2.0-3.0 Loading After Inundation Soil Type SC Rebound Cycle

PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 4546

501113001

USAFA PLANETARIUM CHILLER ADDITION

2120 CADET DRIVE

COLORADO SPRINGS, COLORADO

B-7

3/16

-1.0

1.0

0.1 1.0 10.0 100.0

C O

N S

O

LI

D A

T

IO

N

IN

P E

R C

E N

T O

F S

A M

P

LE

T H

IC

K

N E

S S

E

G A

T

IV

E

IN

D

IC

A T

E S

E X

P A

N S

IO

N

STRESS IN KIPS PER SQUARE FOOT

CONSOLIDATION/SWELL TEST RESULTS

1 PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 4972

2 PERFORMED IN GENERAL ACCORDANCE WITH AASHTO T288

3 PERFORMED IN GENERAL ACCORDANCE WITH CDOT TEST METHOD CP-L 2103

4 PERFORMED IN GENERAL ACCORDANCE WITH CDOT TEST METHOD CP-L 2104

8.2 104,348B-1 & B-2 0.0-9.0 46 0.460

CHLORIDE

CONTENT 3

(ppm) pH 1

SAMPLE DEPTH

(FT)

SAMPLE

LOCATION (Ohm-cm)

RESISTIVITY 1 SULFATE CONTENT 2

(%)(ppm)

501113001 3/16 B-8

USAFA PLANETARIUM CHILLER ADDITION

2120 CADET DRIVE

COLORADO SPRINGS, COLORADO

CORROSIVITY TEST RESULTS

X

Description Symbol Sample Location

Depth (ft)

Shear Strength

4.0-5.5IN SITU B-2 Peak

Cohesion, c (psf)

Friction Angle, φ (degrees)

Soil Type

SC37

SC

Ultimate4.0-5.5B-2

B-9

PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 3080

IN SITU

501113001 3/16

2120 CADET DRIVE

USAFA PLANETARIUM CHILLER ADDITION

COLORADO SPRINGS, COLORADO

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500

S H

E A

R S

T R

E S

S

P S

F

NORMAL STRESS (PSF)

DIRECT SHEAR TEST RESULTS