B3_Solicitation_Amendment-1_W9126G-17-R-0084.pdf

AMENDMENT OF SOLICITATION/MODIFICATION OF CONTRACT

Except as provided herein, all terms and conditions of the document referenced in Item 9A or 10A, as heretofore changed, remains unchanged and in full force and effect.

15A. NAME AND TITLE OF SIGNER (Type or print)

30-105-04EXCEPTION TO SF 30

APPROVED BY OIRM 11-84

STANDARD FORM 30 (Rev. 10-83) Prescribed by GSA

FAR (48 CFR) 53.243

The Solicitation for Automated Infantry Platoon Battle Course (IPBC); Fort Hood, Texas is amended as follows:

See SF30 Continuation Sheet(s)

NOTE: Proposal Receipt date will be, 17 July 2017, at 12:00 p.m. Central Time.

1. CONTRACT ID CODE PAGE OF PAGES

J 1 2

16A. NAME AND TITLE OF CONTRACTING OFFICER (Type or print)

16C. DATE SIGNED

BY

16B. UNITED STATES OF AMERICA15C. DATE SIGNED15B. CONTRACTOR/OFFEROR

(Signature of Contracting Officer)(Signature of person authorized to sign)

8. NAME AND ADDRESS OF CONTRACTOR (No., Street, County, State and Zip Code) X 9A. AMENDMENT OF SOLICITATION NO.

W9126G-17-R-0084

X 9B. DATED (SEE ITEM 11)

10-May-2017

10B. DATED (SEE ITEM 13)

11. THIS ITEM ONLY APPLIES TO AMENDMENTS OF SOLICITATIONS

X The above numbered solicitation is amended as set forth in Item 14. The hour and date specified for receipt of Offer is extended, X is not extended.

Offer must acknowledge receipt of this amendment prior to the hour and date specified in the solicitation or as amended by one of the following methods:

(a) By completing Items 8 and 15, and returning copies of the amendment; (b) By acknowledging receipt of this amendment on each copy of the offer submitted;

or (c) By separate letter or telegram which includes a reference to the solicitation and amendment numbers. FAILURE OF YOUR ACKNOWLEDGMENT TO BE RECEIVED AT THE PLACE DESIGNATED FOR THE RECEIPT OF OFFERS PRIOR TO THE HOUR AND DATE SPECIFIED MAY RESULT IN

REJECTION OF YOUR OFFER. If by virtue of this amendment you desire to change an offer already submitted, such change may be made by telegram or letter, provided each telegram or letter makes reference to the solicitation and this amendment, and is received prior to the opening hour and date specified.

12. ACCOUNTING AND APPROPRIATION DATA (If required)

13. THIS ITEM APPLIES ONLY TO MODIFICATIONS OF CONTRACTS/ORDERS.

IT MODIFIES THE CONTRACT/ORDER NO. AS DESCRIBED IN ITEM 14.

A. THIS CHANGE ORDER IS ISSUED PURSUANT TO: (Specify authority) THE CHANGES SET FORTH IN ITEM 14 ARE MADE IN THE

CONTRACT ORDER NO. IN ITEM 10A.

B. THE ABOVE NUMBERED CONTRACT/ORDER IS MODIFIED TO REFLECT THE ADMINISTRATIVE CHANGES (such as changes in paying office, appropriation date, etc.) SET FORTH IN ITEM 14, PURSUANT TO THE AUTHORITY OF FAR 43.103(B).

C. THIS SUPPLEMENTAL AGREEMENT IS ENTERED INTO PURSUANT TO AUTHORITY OF:

D. OTHER (Specify type of modification and authority)

E. IMPORTANT: Contractor is not, is required to sign this document and return copies to the issuing office.

14. DESCRIPTION OF AMENDMENT/MODIFICATION (Organized by UCF section headings, including solicitation/contract subject matter where feasible.)

10A. MOD. OF CONTRACT/ORDER NO.

2. AMENDMENT/MODIFICATION NO. 5. PROJECT NO.(If applicable)

6. ISSUED BY

3. EFFECTIVE DATE

10-May-2017

CODE

US ARMY ENGINEER DISTRICT, FORT WORTH

ATTN: CESWF-CT

819 TAYLOR ST, ROOM 2A19

P.O. BOX 17300

FORT WORTH TX 76102-0300

W9126G 7. ADMINISTERED BY (If other than item 6)

4. REQUISITION/PURCHASE REQ. NO.

CODE

See Item 6

FACILITY CODECODE

EMAIL:TEL:

W9126G-17-R-0084

SECTION SF 30 BLOCK 14 CONTINUATION PAGE

SUMMARY OF CHANGES

1. FOUNDATION AND PAVEMENT DESIGN ANALYSIS – Foundation and Pavement Design Analysis has been added to this solicitation.

End of Summary of Changes

JUNE 2016

FORT HOOD, TEXAS

INFANTRY PLATOON BATTLE COURSE (FY17)

FOUNDATION AND PAVEMENT DESIGN ANALYSIS

PREPARED BY

U.S. ARMY CORPS OF ENGINEERS

FORT WORTH DISTRICT

ENGINEERING AND CONSTRUCTION DIVISION

GEOTECHNICAL BRANCH

CESWF-EC-G

FOUNDATION AND PAVEMENT DESIGN ANALYSIS

1. General. The purpose of this report is to provide foundation and pavement design recommendations for a new Infantry Platoon Battle Course (IPBC) at Fort Hood. The project area is divided into the Range Operations Control Area (ROCA), which includes the

(habitable/functional) range exercise buildings, and the Training Area, which includes numerous stationary and moving armor targets (SATs and MATs, respectably) and infantry targets (SITs and MITs, respectively), to be accessed by range access roads (all aggregate-surfaced). Buildings located at the project Range Operations Control Area include an 800 GSF

Classroom Building, an 800 GSF Range Operations and Storage building, both of which will be single-story, pre-engineered metal buildings. The Range Operations and Control Area also includes a 726 GSF Bleacher Enclosure and a 273 GSF Ammunition Breakdown Building, which will both be single-story, pre-engineered metal buildings. A single-story 248 GSF

Range Control Tower will also be constructed in the ROCA. The Range Control Tower will be a supported metal frame structure with a finish floor level approximately 10.0 feet above grade. The Training Area includes an Assault Defend House; based on prior similar facilities, this building is anticipated to be a two-story wood structure with ballistic rubber facing.

Pavement features for the new facility include aggregate-surfaced range access roads and parking areas. Site improvements are anticipated to include new utilities.

The new Infantry Platoon Battle Course will be constructed in the northern part of the

Fort Hood Range, approximately 4.5 miles south of the North Fort Hood cantonment, near the intersection of West Range Road and Owl Creek Road. The project site is generally relatively flat, with gradients varying from approximately 2 to 5 percent across the ROCA site area, sloping toward the east. The ROCA has relatively sparse foliage; however the Training Range area has a dense cover of foliage. Existing grades across the area of new construction in the

ROCA range from approximately 1,023.0 feet to 1,030.0 feet National Geodetic Vertical

Datum (NGVD). The following finish floor elevations are established for project structures at the time of this report:

Structure Finish Floor Elevation, feet (NGVD)

Classroom Building 1,028.50

Range Operations and Storage Building 1,028.50

2. Subsurface Investigation. The U.S. Army Corps of Engineers, Fort Worth District, drilled a total of four (4) test holes at the Infantry Platoon Battle Course site in May 2016. Borings

8A4C-5956 through 8A-5959 were drilled to determine subsurface conditions and to obtain representative soil and rock samples for laboratory testing. Test hole advancement and sample recovery was performed using 6.25-inch (outer diameter) hollow stem continuous diameter short flight augers, a 6-inch (outer diameter) roller bit, a 4-inch (inner diameter) diamond bit core barrel sampler, a 2-inch (outer diameter) split spoon sampler, and a nominal 3-inch diameter shelby tube sampler. Samples recovered from the borings were sealed in airtight containers and taken to the laboratory of TEAM Consultants, Incorporated (Arlington, Texas) for testing. The borings were advance to total depths ranging from 8.2 feet to 40.8 feet below existing grade. Tabulated below are the borings and their approximate locations with respect to the proposed ROCA structures:

Boring ROCA Structure

8A4C-5956 Range Control Tower

8A-5957 Classroom Building

8A-5958 Range Operations and Storage Building

8A-5959 Ammunition Breakdown Pad

One additional boring (8A4C-5960) was scheduled to be drilled at the Trench site approximately 1.3 miles southeast of the ROCA site. However, access to this area was closed at the time of the geotechnical subsurface investigation due to Range Operations activity.

The field investigation was performed using a Gus Pech 1300C truck-mounted drill rig and conventional drilling attachments. Results of the field investigation are shown on Sheet

B101 (Boring Location) and Sheet B201 (Log of Boring) (Appendix A).

a. Groundwater Conditions. Groundwater conditions were monitored during and upon completion of drilling, and after observation periods of up to 16 hours after completion of drilling. Static water levels were measured in one of the four borings drilled at the site.

Specifically, a static water level of 30.8 feet was measured in boring 8A4C-5956 at the time of the field investigation. It should be noted that groundwater conditions are relative to the time of drilling, annual precipitation, and drainage conditions at the site.

b. Dynamic Cone Penetrometer Testing. Dynamic Cone Penetrometer (DCP) testing was performed for pavement design considerations in all four borings. DCP test results are in presented in Appendix D and discussed in paragraphs 4 and 5.

c. Soil Resistivity Testing. A soil resistivity test was performed at the location of boring 8A4C-5956 (approximate location of the Range Control Tower). A diode spacing of 2.5 feet was used for all soil resistivity testing. The resistivity value measured in the field at the location of boring 8A4C-5956 is 3,399 ohm-cm. Soil resistivity test results are provided in the

‘Remarks’ column of the aforementioned logs of borings (Appendix A).

3. Subsurface Conditions.

a. General Geology. Fort Hood lies within the Central Texas Section of the Great

Plains physiographic province. The topographic features of the area are those of a dissected plateau characterized by buttes and mesas. Approximately 30 miles southeast of Fort Hood, the dissected plateau topography gives way to the moderate or rolling relief of the Gulf Coastal

Plain. The Balcones fault zone is, roughly, the dividing line of the two physiographic provinces. The uppermost primary stratum underlying Fort Hood is the Walnut Formation of the Comanche Series, Cretaceous age. The Walnut Formation is composed of gray-black, calcareous clay shales alternating with beds of chalky, nodular limestone and shell conglomerates.

Overburden soils within the area vary from a knife-edge to greater than 30 feet in thickness, and consist of clays of low to high plasticity, clayey gravels and/or clay choked limestone nodules. The overburden soils are residual and derived from the underlying parent material.

b. Site Conditions. The Infantry Platoon Battle Course project site is generally relatively flat, with gradients varying from approximately 2 to 5 percent across the ROCA site area, sloping toward the east. The ROCA has relatively sparse foliage; however the Training

Range area has a dense cover of foliage. Existing grades across the area of new construction in the ROCA range from approximately 1,023.0 feet to 1,030.0 feet National Geodetic Vertical

Datum (NGVD).

Based on the information presented on the logs of borings and the results of laboratory classification testing, the Infantry Platoon Battle Course (FY17) project site is characterized by subsurface strata consisting of high plasticity clay (CH) overburden soils that are underlain by formations of weathered marl/shale and limestone. The overburden stratum consists of high plasticity clay (CH) that is firm, moist, dark brown to brown to red brown, and slightly sandy, with scattered limestone gravel near the contact with the underlying weathered primary contact. It should be noted that the high plasticity clay overburden is most likely a weathering product of the limestone and marl/shale primary, and the limestone gravel observed near the contact with the weathered primary is likely a very badly weathered primary material above the intact primary. The CH clay overburden was only encountered at one of the test hole locations, specifically in boring 8A-5958 (approximate location of the Range Operations and Storage

Building). At this location, the high plasticity clay overburden is present from the surface to a depth of 4.3 feet below existing grade. The weathered primary (weathered marl/shale) was present at the surface or immediately underlying pavement materials at the locations of the other three test holes drilled for this project. Atterberg limits testing on the CH clay overburden soils collected from boring 8A-5958 indicates that these materials possess liquid limits ranging from 54 to 75 percent, plastic limits varying from 21 to 28 percent (with plasticity indices ranging from 33 to 47 percent), and in situ moisture contents varying from about 20 to 34 percent.

The uppermost primary stratum encountered at the test hole locations is a weathered marl/shale. The weathered marl/shale is red brown to yellow brown, soft (Rock

Classification), dry to moist, silty, sandy, interbedded with limestone seams (which exhibit the appearance of gravel when disturbed by auger drilling action). Atterberg limits testing on specimens of the marl/shale primary (and marl/shale interbedded within weathered limestone strata) indicates that these materials possess liquid limits ranging from 24 to 83 percent, plastic limits varying from 15 to 27 percent (with plasticity indices ranging from 6 to 56 percent), and in situ moisture contents varying from about 11 to 34 percent. A stratum of predominantly weathered limestone primary (interbedded with marl/shale primary) was encountered within boring 8A4C-5956 at a depth of 5.5 feet below existing grade; the remaining three borings encountered auger “refusal” on top of limestone primary underlying the marl/shale primary at depths ranging from 8.2 feet to 10.8 feet below existing grade. The weathered limestone is light yellow brown and gray, moderately hard to hard (Rock Classification), massive bedded, fractured, chalky to argillaceous, microfossiliferous, weathering nodular in approximately the upper 17.4 feet (in boring 8A4C-5956), and interbedded with marl/shale seams. The weathered limestone primary persisted to the total depth investigated, 40.8 feet (in boring 8A4C-5956).

Regardless of the state of weathering, excavations made into the weathered marl/shale or limestone primary should be considered “rock excavation”.

Based on the geotechnical field investigation, the Infantry Platoon Battle Course

(FY17) project site is assigned International Building Code (IBC) Site Class D.

Subsurface conditions representative of the Infantry Platoon Battle Course (FY17) project site are shown on the boring logs, Sheet B201 (Appendix A). The legend on the individual boring logs show overburden materials as classified in the laboratory using procedures presented in ASTM D 2488 and classified in the field using procedures presented in

ASTM D 2487. It should be noted that the actual interface between material types might be far more gradual or abrupt than presented; therefore, actual subsurface conditions in areas not sampled may differ from those predicted. The nature and extent of variations across the site may not become evident until construction commences, and the actual construction process may alter subsurface conditions as well. If variations become evident at the time of construction, CESWF-EC-G should be contacted to determine if the recommendations presented in this report need to be reevaluated.

4. Testing.

a. Laboratory Testing. Representative samples of the overburden soils recovered from selective borings were subjected to laboratory testing for identification, moisture content, grain-size distribution, Atterberg limits, density, and strength. The accumulative test results are tabulated and presented in Appendix C. Results of identification and moisture content testing are shown on the individual boring logs, Appendix A.

Results of laboratory testing performed on samples obtained from the Infantry Platoon

Battle Course site are presented graphically in Appendix B as follows: Plasticity characteristics are shown on Plate 1, Plasticity Chart. Moisture content values of representative samples are shown with respect to depth on Plate 2. Atterberg limits test results are shown with respect to depth on Plate 3. Dry density values of representative undisturbed samples and their corresponding moisture contents are shown with respect to depth on Plate 4.

Ultimate compressive strengths of the limestone primary (interbedded with marl/shale) are shown with respect to depth on Plate 5.

(1) Shear Strength Testing. Shear strength characteristics of the weathered and unweathered limestone were analyzed in the laboratory using one-point unconsolidated-undrained (UU) triaxial compression testing and unconfined compression (UC) testing.

Specimens subjected to one-point UU triaxial compression testing are indicated below by

“UU” following the recorded compressive strength. The ultimate compressive strengths recorded are presented below and in Appendix C at the end of this report.

Boring Depth, ft γd, pcf Qu, tsf Material Type

8A4C-5956 24.6 131.2 48.31 (UU) Weathered Limestone 8A4C-5956 29.5 132.8 83.58 Weathered Limestone 8A4C-5956 33.8 130.9 83.42 Weathered Limestone 8A4C-5956 37.2 135.3 50.64 (UU) Weathered Limestone 8A4C-5956 38.9 129.5 5.81 (UU) Weathered Limestone

b. Field Testing. Dynamic Cone Penetrometer (DCP) testing for pavement design considerations was performed in all six borings. A DCP consists of a steel rod with a steel cone attached to one end and a sliding single-mass hammer. For this project, the DCP test was performed by driving the steel cone into the soil using a 10.1-pound sliding hammer dropped from a height of 22.6 inches (574 millimeters). The number of blows required for each 0.4 inch (10-mm) or greater of penetration was recorded as the “penetration per blow set”;

therefore, the more penetration achieved per blow indicates that a “weaker” soil layer was encountered. Typically, penetration measurements are taken to a depth of 39.4 inches (1000 millimeters) or when refusal is achieved. Refusal is defined as the point at which the cone cannot penetrate the soil more than 0.4 inches (10 millimeters). Presented below are the average in situ strength parameters derived from the DCP tests. DCP test results (correlated

CBR and subgrade modulus values versus depth) are also presented in Appendix D at the end of this report.

Depth, in CBR, % k, pci

0 – 6 2 – 2 70 – 86 6 – 12 2 – 18 80 – 212 >12 5 – 28 130 – 294

5. Discussions. The following discussions are provided in support of the foundation and pavement design recommendations made for the proposed Infantry Platoon Battle Course.

a. Soil Activity Considerations. Subsurface conditions in the area of the ROCA building construction consist of high plasticity clay (CH) that is underlain by formations of weathered marl/shale and limestone primary (which was present at the surface in borings drilled at the approximate locations of the Classroom Building, Range Control Tower, and

Ammunition Breakdown Pad. Based on laboratory test results, the clay overburden soils and marl/shale primary materials are moisture deficient to a depth of approximately 10 feet below existing grade and therefore will be susceptible to volumetric changes during periods of seasonal moisture variations. In this zone, liquid limits range from 24 to 83 percent, plastic limits vary from 15 to 28 percent (with plasticity indices ranging from 6 to 56 percent), and natural moisture contents vary from 11 to 34 percent. Based on the plasticity characteristics of the clay overburden and marl/shale primary materials encountered during the field investigation at the Infantry Platoon Battle Course (FY17) project site, and upon the results of controlled expansion-consolidation (CEC) testing on similar subsurface materials at Fort Hood, the in situ clay overburden soils have a moderate to very high expansion potential and a moderate to high consolidation potential. The weathered marl/shale primary has a moderate expansion potential and a low to moderate consolidation potential. Based on these conditions, special foundation and subgrade preparation requirements are provided herein for the Infantry

Platoon Battle Course to mitigate the effects of the active subgrade materials.

b. Foundation Design Considerations. Most of the new structures included in this project are relatively small, lightly-loaded single-story facilities. A deep drilled pier foundation system is not considered necessary or appropriate for these facilities. Instead, a shallow foundation system is considered better suited to these structures. The best shallow foundation performance by similar structures in the expansive subsurface material conditions present at Fort Hood has been achieved by two types of shallow foundation systems: a reinforced concrete ribbed mat slab and a reinforced concrete flat mat slab. These two shallow foundation systems, when properly designed and constructed, will act monolithically when subjected to shrink-swell movements of the subsurface materials. A reinforced concrete spread footing foundation system is typically not recommended for structures at Fort Hood due to the high shrink-swell potential of the overburden clay soils and marl/shale primary. Due to the depth of excavation required for the Offense/Defense House, the foundation for this structure will be within sandy, clayey gravel material, well below the upper high plasticity clay overburden. Therefore, a reinforced concrete spread footing foundation system can be considered for the Offense/Defense House (in addition to the reinforced concrete ribbed mat and flat mat slab foundation system options). It is permissible to consider a reinforced concrete spread footing foundation system for the structures other than the Range Operations and Storage Building due to the absence of high plasticity overburden clay at the other ROCA building locations; however the structural designer should be aware that this foundation system will still have a greater potential for differential movement due to the plastic marl/shale primary compared to the monolithic mat slab foundation systems, which are the primary recommended foundation systems for the project facilities.

c. Pavement Design Considerations. The pavement designs presented in this report are based on criteria contained in UFC 3-250-01FA, TM 5-822-2, UFC 3-250-09FA, and engineering judgment.

(1) Traffic Types and Conditions. There is one (1) pavement structure proposed for this project, specifically aggregate-surfaced Range Surface Roads and Parking

Areas.

Types of vehicles that may utilize the pavement areas are anticipated to include

Category II (HMMVW) Traffic potentially making greater than 210 passes per day (resulting in a pavement Design Index equal to 2 per UFC 3-250-09FA), and large multi-axle trucks

(Category IVA Traffic) making fewer than 210 passes per day (resulting in a pavement Design

Index equal to 4 per UFC 3-250-09FA). The larger multi-axle truck traffic is determined to govern the pavement design. At the time of this report, large track-laying tactical vehicles

(e.g., 120-kip M1 Abrams Tanks and 60-kip M2 Bradley Fighting Vehicles) are not anticipated to utilize the project pavement features. If these larger tactical vehicles may or will be expected to utilize the project pavement features, or if there are specific other large pneumatic tire vehicles which may exceed Category IVA loading and which will utilize the project, CESWF-EC-G should be contacted immediately to analyze the specific anticipated traffic loading conditions and provide pavement sections to accommodate these larger vehicles.

Based on the aforementioned Unified Facilities Criteria, the anticipated traffic conditions were assigned:

Pavement Structure Traffic Category Road Class Design Index

Range Service Roads and Parking Areas IVA F 4*

*Note: The Road Class and Design Index for the aggregate-surfaced pavement structures were determined in accordance with criteria contained in UFC 3-250-09FA.

(2) Subgrade Conditions and Pavement Design Parameters. California Bearing

Ratio (CBR) and plate bearing tests were not performed for this project. Instead, dynamic cone penetrometer (DCP) testing was conducted to evaluate the raw subgrade for pavement design considerations. The penetration resistance obtained from the DCP test is a measure of the soil’s relative density, with in turn is used to derive “in situ” CBR and modulus of subgrade reaction values.

The average in situ CBR values measured within the upper 12 inches of soils tested at the Infantry Platoon Battle Course site range from approximately 2 to 18 percent, and below this depth, CBR values range from 5 to 28 percent. Modulus of subgrade reaction values measured within the upper 12 inches of soils tested range from 70 to 212 pci, and below this depth, modulus of subgrade reaction values range from 130 to 294 pci. The pavement structures for this project are all aggregate-surfaced. Therefore, the pavement design shall be based on CBR values. In the past, the clayey subgrade at Fort Hood has been assigned CBR values between 4 and 6 percent when compacted to 90 percent of laboratory maximum density.

The lower CBR values measured within the upper 18 inches at this site were within the high plasticity clay overburden soil (present at the surface at the location of boring 8A-5958). CBR values measured within the marl/shale primary and existing base course materials were comparable to higher than those measured within the high plasticity clay; the higher CBR values are believed to be attributable to the presence of gravel or limestone clasts/seams in the base course and marl/shale primary, respectively. Based on these considerations, a design

CBR of 4 percent is assigned to the raw subgrade when compacted to 90 percent of laboratory maximum density (ASTM D 1557).

(3) Material Sources. Material sources in central Texas are capable of producing a high quality crushed aggregate for concrete mixes to meet strength requirements.

For this reason, a concrete flexural strength of 650 psi at 28 days was considered in the design of rigid pavements. To date, Alkali/Silica Reaction with Portland Cement Concrete has never been a problem when using local aggregate sources.

6. Recommendations. The following foundation and pavement design recommendations are based on results of the field investigation and laboratory testing, the criteria cited herein, and engineering judgment.

a. Foundation Design Recommendations.

(1) Foundation System.

(a) Reinforced Concrete Ribbed Mat or Flat Mat Slab. The Infantry

Platoon Battle Course buildings can be supported on a reinforced concrete ribbed mat slab or flat mat slab. The mat slabs shall be conventionally reinforced – POST-TENSIONED

SLABS ARE NOT ALLOWED. Based on the plasticity level of the near surface clayey soils and plastic weathered marl/shale primary, the mat slabs shall be analyzed and designed for 1.0 inch of long-term differential movement. For this reason, interior ribs for ribbed mat slabs shall be spaced no further than 20 feet center-to-center, and diagonal stiffener ribs shall be placed at each corner of the mat slab. Additional stiffness may be needed for irregular slab geometries. Design of the mat slabs shall meet the minimum requirements as presented in

CESWD-ED-TS/G Criteria Letter, dated 29 January 1988 – Design Criteria for Ribbed Mat

Foundations, SWDED-G Criteria Letter, dated 16 April 1987 – Criteria for Developing

Geotechnical Design Parameters for SWD Ribbed Mat Design Methodology (included as

APPENDIX E of this report), and the recommendations and requirements provided herein.

Interior and exterior beams should bottom a minimum of 24 inches below outside finished grade. An allowable bearing capacity of 2.0 ksf (net) should be used to size the beams. For this phase of design, it should be noted that (1) the structural load is supported solely on the beam and the beam intersections, (2) load transfer occurs over the effective beam width, and (3) the beam and soil remain in contact. Beam intersections should be widened at column locations to accommodate the above allowable bearing value for the anticipated load condition. The load used to size the beams should consist of full dead load plus that portion of the live load that acts more or less continuously, usually 50 percent.

The ribbed mat slab foundations should incorporate adequate stiffness such that the deformations do not exceed the structural tolerance of any elements in the foundation or superstructure. Analyses should consider a vertical separation of the foundation slab and beams from the subgrade of 1.0 inch at the outside of all perimeter beams, with loss of support beneath the foundation over a horizontal distance of not less than 6.5 feet. This loss of support condition corresponds to the center lift mode. Additionally, edge lift analyses should consider an edge moisture variation distance equal to 3.0 feet, and an edge lift heave of

1.0 inch should be used in the design of the ribbed mat slab. This edge lift heave corresponds to an applied structural pressure of 100 psf. For edge lift considerations, two additional combinations of pressure and swell are required. For an allowable bearing capacity of 2.0 ksf, an edge lift heave of 0.75-inch can be expected to occur. At an ultimate bearing capacity of

6.0 ksf, 0.5-inch of heave should be anticipated. It should be noted that these anticipated heave amounts are based on the removal of 3.0 feet of existing materials under building floor slabs and replacement with compacted nonexpansive fill, as required herein. Mat slab designs shall incorporate appropriate stiffness and isolation measures, as previously stated, in order to ensure the foundation will perform monolithically and minimize stress concentrations induced by irregular building geometries. These measures shall include additional stiffness at corners and isolation of slab units to limit deflections to tolerable limits not affecting the façade and interior wall/ceiling finishes.

A modulus of subgrade reaction equal to 200 psi/inch should be used when analyzing the ribbed mat slabs to determine in-service deformations. This value, however, should be factored to account for width effects such that kdesign=k1(Beff), where Beff is the effective beam width in feet. Design of the ribbed mat slabs shall use the SWD-AEIM sections as a minimum stiffness "first approximation".

A flat mat shall have a uniform thickness of not less than 18 inches. An allowable bearing capacity of 2.0 ksf (net) shall be used to size the mat foundation. The mat should be tapered as required to ensure the perimeter of the slab extends to a constant elevation and is at least 24 inches below outside finish grade. Flat mat slabs also shall incorporate adequate stiffness such that the deformations do not exceed the structural tolerance of any element of the foundations or superstructures nor cosmetic cracking of interior and exterior finishes. Control joints/panels shall be incorporated within interior finishes and exterior facades to help control potential cracking due to slab movements. The load used to size the flat mat slab shall consist of full dead load plus that portion of the live load that acts more or less continuously, usually

50 percent.

The mat slabs will, by design, be supported on-grade. A polyethylene vapor barrier

(10-mil minimum thickness) and a minimum 6-inch capillary water barrier shall be placed beneath the mat slab. (However, see note in Paragraph 6.a.(3) for approved exceptions to this requirement.)

(b) Reinforced Concrete Spread Footings. Alternatively, the Assault

Defend House can be supported on a foundation system consisting of dug and formed reinforced concrete continuous spread and/or spot spread footings. The footings should bear at a uniform depth, but at least 2.0 feet below outside finish grade. The footings should be sized for an allowable bearing pressure of 2,000 psf. If, due to site grading requirements, footings must be placed at depths shallower than 3.0 feet below existing grade, or if footings must be placed in fill above existing grade, the existing soils below the footings should be removed

(excavated) to a depth of 3.0 feet below existing grade. Nonexpansive fill shall then be placed in controlled lifts not exceeding 8 inches in loose thickness and compacted to at least 95 percent of maximum laboratory density as determined in accordance with ASTM D 1557 between the excavation surface and the base of the footings. Footings founded within fill above existing grade or at depths shallower than 3.0 feet below existing grade, in compliance with the earthwork requirements specified herein, should be sized for an allowable bearing pressure of 2,000 psf. In addition to the requirements above, and regardless of the founding depth, a minimum of 1.0 foot of nonexpansive fill compacted to at least 95 percent of maximum laboratory density as determined in accordance with ASTM D 1557 shall be placed beneath all reinforced concrete spread footing foundations.

The load used to size the footings should consist of full dead load plus that portion of the live load that acts more or less continuously, usually 50 percent.

Load-carrying masonry walls (if used) should be supported on a minimum 18-inch wide continuous footing founded as stated above. Non-load bearing masonry walls (partitions) can be placed on a minimum 12-inch wide “shovel beam” footing.

(c) Small Support-type Structures. Small support-type structures (<500

GSF), can be supported on reinforced concrete slabs-on-grade with turned-down edge beams.

The turned-down edge beam should extend a minimum of 12 inches below outside finished grade and can be sized for a safe bearing pressure of 2,000 psf (net). Subgrade preparation should consist of removing a minimum of 24 inches of existing soil within the building footprint and replacing to the bottom of the floor slab with compacted nonexpansive fill below the soil-supported slab. If intact limestone primary is encountered prior to reaching the 24-inch depth, excavation operations can be stopped and the nonexpansive fill can then be placed.

(2) Floor Slab Systems. The mat slab foundations will, by definition, be placed on-grade. If the Assault Defend House is founded on reinforced concrete continuous spread or spot spread footings, ground-level floor slabs, where applicable, can be placed on-grade. Floor slabs placed on-grade should be isolated from any portion of the building structure using ½-inch expansion joints. In doing so, the building structure-floor slab interface should be designed to accept vertical movements so that the operation of the facility will not be affected.

This will result in the best performance. Transitional areas, such as door openings, can be doweled to prevent offsets from occurring. In these areas, the slab should bear on the grade beam to create a single joint at one face of the grade beam. Slab edges should extend to the outside face of the grade beam at the exterior door locations. A polyethylene vapor barrier

(10-mil minimum) and a minimum 6-inch capillary water barrier should be placed beneath floor slabs placed on-grade.

If any ground-level floor slabs within the Assault Defend House (if supported on footings) must be structurally-supported, these floor slabs shall be supported above a minimum

12-inch void.

(3) Subgrade Preparation and Fill Requirements. Subgrade preparation for structures with ribbed mat slab foundations, flat mat slab foundations, and slabs with turned down edge beams shall consist of removing the existing clayey soils within the proposed building footprints to a minimum depth of 3.0 feet, or to the top of intact limestone primary, whichever occurs first, and replacing with compacted nonexpansive backfill material, which should limit the magnitude of predicted movement to approximately 1 inch or less. Any additional fill required to achieve the final subgrade elevation below the floor slab system shall be nonexpansive material as well. The upper 6 inches of existing subgrade exposed after excavation operations, or cleared prior to fill placement shall be scarified, moistened, manipulated, and recompacted to the same density required for nonexpansive fill materials.

Nonexpansive fill shall be placed in controlled lifts not exceeding 8 inches in loose thickness and compacted to at least 95 percent of laboratory maximum density (in accordance with

ASTM D 1557) A polyethylene vapor barrier (10-mil minimum thickness) and a minimum 6-inch capillary water barrier shall be provided beneath floor slabs supported on-grade.

NOTE: The vapor barrier and capillary water barrier are not required beneath exterior mat slabs-on-grade that are not enclosed and are exposed to the elements (e.g., mechanical equipment pads) and are not connected to a building.

Based on previous experience, if nonexpansive fill is placed outside the limits of the building footprint, the relatively higher permeability of the nonexpansive fill will allow moisture to infiltrate to the highly expansive soils adjacent to and beneath the foundation, potentially resulting in heave of the foundation. To limit moisture penetration to the area around and beneath the foundation, excavated areas beyond the limits of the building footprint shall be backfilled with select clay backfill materials. This select clay cap shall be a minimum of 2 feet in thickness and shall extend from the building perimeter to the limits of the excavation (completely capping/covering the compacted nonexpansive fill). Select clay backfill materials should be compacted to at least 92 percent of laboratory maximum density

(with all other subgrade preparation and fill placement requirements being the same as those for nonexpansive fill).

For structurally-supported floor slab areas (if used) in the Assault Defend House, if a footing foundation system is used, subgrade preparation shall consist of removing the upper 12 inches of existing materials and replacing with a compacted select backfill. Any additional fill required to raise the subgrade to the final elevation(s) below the building floor slab system shall be select material as well. Select fill shall be placed in controlled lifts not exceeding 8 inches in loose thickness and compacted to at least 90 percent of laboratory maximum density as determined in accordance with ASTM D 1557. For portions of the building pad that will be a cut section, subgrade preparation shall consist of removing all existing materials to a depth that allows a minimum 12-inch void to be formed below the floor slab system. The upper 6 inches of existing subgrade exposed after cut and/or fill operations shall be scarified, moistened, and recompacted to the same density required for select fill.

(4) Below-Grade Structures (Including Retaining Walls) (If Applicable). The following information is provided for the design of below-grade structures, if applicable. All structures shall be designed using an at-rest lateral earth pressure coefficient of (ko) 0.7, an angle of internal friction (φ) equal to 28o, a cohesion value (c) of 100 psf, and an allowable bearing capacity of 2.0 ksf. The backfill material should be assumed to have a moist unit weight of 125 pcf and all backfill should be nonexpansive. Temporary and permanent drainage measures, such as foundation drains, sumps, and pumps, should be incorporated into the design of basements and tunnels. Analyses and designs for below grade structures (including retaining walls) should also account for surcharge loadings (e.g., due to vehicular traffic), where applicable.

(5) Berms (if applicable). Earthfill berms, if applicable, should be constructed of Satisfactory Materials (per the definition in this report). The materials used to construct the berms should have the following plasticity index (PI) characteristics: 15 < PI < 30. The earthfill for the berms shall be placed in controlled lifts not exceeding 8 inches in loose thickness and compacted to at least 92 percent of maximum laboratory density as determined in accordance with ASTM D 1557. Additionally, 6 inches of the existing subgrade material beneath the base of the berms should be scarified, moistened, aerated, and recompacted to at least 90 percent of maximum laboratory density as determined in accordance with ASTM D

1557.

(6) Drainage and Care of Water. Proper drainage is an important design consideration to ensure satisfactory long-term foundation performance. Exterior grading adjacent to the buildings should be sloped away from the structures a minimum of 5 percent for the first 10 feet. Runoff from the roofs should be adequately discharged away from foundation edges. In no case should water be allowed to pond adjacent to or beneath the buildings, both during and after construction.

Drainage of ground and surface water from the project site continually throughout the construction contract is essential. The contractor shall be required to protect the excavation and all constructed work throughout the life of the contract by means of ditches, berms, sumps with pumps, and any other means required to continually and effectively remove water from the site at all times. Ponding of water in building excavations is unacceptable at any time. In addition, site excavations to include the utility trenching, grading, and retention basins shall be constructed so as not to supply water directly or indirectly to the buildings or underlying active clayey soils and marl/clay shale. Such exposure of the underlying active clayey soils and marl/clay shale to surface runoff during construction could extend the active zone (via fractures) to much greater depths within the marl/clay shale. This would activate these highly expansive materials and result in expansion pressures on the foundation elements that could create distress on the structural system of the buildings. These requirements shall be reflected in the specifications and in the structural notes.

(7) Mechanical Connections. All exterior mechanical connections should be of the flexible type. Flexible connections shall be capable of resisting a minimum of 1 inch of both vertical and horizontal movement. All mechanical/structural connections between slabs on grade and building perimeter entry/exit points must be designed and constructed to handle up to 1 inches of vertical movement. All condensate lines shall drain away from foundation edges. It is recommended that below-grade utility lines connecting to the buildings be aligned under the centerline of the respective building footprint. The use of exterior lines connecting to the buildings by numerous utility trenches is discouraged, as this would create high permeability pathways for moisture to gain access to, and activate, the expansive clay and marl/shale materials within the building footprint.

(8) Backfill Adjacent to Exterior Grade Beam Excavation. Use select clay backfill adjacent to exterior grade beam excavation to minimize water penetration to expansive subsoils.

(9) Material Testing Requirements. Testing shall be the responsibility of the contractor to ensure that the subgrade, fill, and backfill materials are properly compacted. To this end, the following frequencies of testing shall be included in the contract as a minimum:

• In-place density of the subgrade, fills, and backfills shall be performed for every 2000 square feet per lift in accordance with ASTM D 1556 or ASTM D 6938.

• Optimum Moisture and Laboratory Maximum Density of nonexpansive fill and backfill shall be performed for every 500 cubic yards or when any change in material occurs.

(10) Foundation Material Definitions.

(a) Satisfactory Materials. Satisfactory materials include materials classified in ASTM D 2487 as GW, GM, GC, GP, SW, SP, SM, SC, CL, and CH and shall be free of trash, debris, roots or other organic matter, or stones larger than 3 inches in any dimension.

(b) Unsatisfactory Materials. Unsatisfactory materials include materials classified in ASTM D 2487 as Pt, OH, OL, ML, MH and any other materials not defined as satisfactory.

(c) Nonexpansive Soils. Nonexpansive soils shall meet the requirements of Texas Department of Transportation Standard Specification for Base Course, Item 247, Type

A, Grade 1 or 2, with a plasticity index of not less than 4 percent nor greater than 12 percent when tested in accordance with ASTM D 4318.

(d) Select Soils. Select soils are satisfactory material having a liquid limit of 35 percent or less and a plasticity index not less than 8 nor greater than 18 when tested in accordance with ASTM D 4318.

(e) Select Clay Backfill. Select clay backfill shall be a satisfactory material having a liquid limit of 35 percent or less, and a plasticity index of not less than 8 nor greater than 20 when tested in accordance with ASTM D 4318, and classifying as a CL in accordance with ASTM D 2487.

(f) Cohesionless and Cohesive Materials. Cohesionless materials include materials classified in ASTM D 2487 as GW, GP, SW, and SP. Cohesive materials include materials classified as GC, SC, ML, CL, MH, and CH. Materials classified as GM and SM will be identified as cohesionless only when the fines are nonplastic.

(g) Capillary Water Barrier. Capillary Water Barrier shall consist of clean, crushed, nonporous rock, crushed gravel, or uncrushed gravel. The maximum particle size shall be 1.5 inches and no more than 2 percent by weight shall pass the 3/16-inch size

(No. 4) sieve.

The above material definitions, subgrade preparation procedures, and material testing requirements should be presented in guide specification UFGS-31 00 00 EARTHWORK.

b. Pavement Design Recommendations. The following pavement sections were derived from criteria contained in UFC 3-250-01FA, TM 5-822-2, UFC 3-250-09FA, and engineering judgment.

(1) Aggregate-Surfaced Pavements. The following pavement section is recommended for Range Service Roads and Parking Areas. The aggregate-surfaced pavement design considers a CBR value of 4 for the raw subgrade when compacted to 90 percent of maximum laboratory. This pavement section is designed to accommodate Category IVA

Traffic and a Class F Road (DI=4, per UFC 3-250-09FA).

5” Aggregate-Surface Course compacted to at least 100 percent of maximum laboratory density (ASTM D 1557)

5” Aggregate Base Course compacted to at least 95 percent of maximum laboratory density (ASTM D 1557)

6” Raw Subgrade compacted to at least 90 percent of maximum laboratory density (ASTM D 1557)

The following notes should be incorporated as part of the pavement details shown on the contract drawings.

1. "The moisture content shall be at least 1 percent above optimum during compaction of the raw subgrade."

(2) Pavement Material Definitions.

(a) Aggregate Surface Courses. The material shall conform to the requirements of UFGS-32 15 00 AGGREGATE SURFACE COURSE and the following requirements (which shall be incorporated into UFGS-32 15 00). The table below shows the permissible gradations for granular material used in aggregate surface roads. Gradation requirements specified below shall apply to the completed aggregate surface. Aggregate gradation shall be made in conformance with ASTM C 117, ASTM C 136, and ASTM D 422.

Sieves shall conform to ASTM E 11. It shall be the responsibility of the Contractor to obtain materials that will meet the gradation requirements after mixing, placing, compacting, and other operations.

Sieve Designation No. 1 No. 2

1 in. 100 100

3/8 in. 50-85 60-100

No. 4 35-65 50-85

No. 10 25-50 40-70

No. 40 15-30 24-45

No. 200 8-15 8-15

The portion of the completed aggregate surface course passing the No. 40 sieve shall have a maximum liquid limit of 35 and a plasticity index of 4 to 9 (ASTM D 4318). Sampling for material gradation, liquid limit, and plastic limit tests shall be taken in conformance with

ASTM D 75. When deemed necessary, the sampling will be observed by the Contracting

Officer.

The material retained on the No. 4 sieve shall be known as coarse aggregate. Coarse aggregates shall be reasonably uniform in density and quality. The coarse aggregate shall have a percentage of wear not to exceed 50 percent after 500 revolutions as determined by ASTM C

131. The amount of flat and/or elongated particles shall not exceed 20 percent. A flat particle is one having a ratio of width to thickness greater than three; an elongated particle is one having a ratio of length to width greater than three. When the coarse aggregate is supplied from more than one source, aggregate from each source shall meet the requirements set forth herein. The material passing the No. 4 sieve shall be known as fine aggregate. Fine aggregate shall consist of screenings, sand, soil, or other finely divided mineral matter that is processed or naturally combined with the coarse aggregate.

The aggregate material shall be placed on the underlying course in layers of uniform thickness. When a compacted layer of 6 inches or less is specified, the material may be placed in a single layer; when a compacted thickness of more than 6 inches is required, no layer shall exceed 6 inches nor be less than 3 inches when compacted.

(b) Aggregate Base Course. Aggregates shall conform to the requirements of UFGS-32 11 23 AGGREGATE AND/OR GRADED-CRUSHED

AGGREGATE BASE COURSE and the following requirements (which shall be incorporated into UFGS-32 11 23). The gradation should conform to the requirements of TXDOT Std Spec, Item 247, for Type “A”, Grade 1 material with a plasticity index no greater than 10.

Aggregates shall not show more than 50 percent loss when subjected to the Los Angeles abrasion test in accordance with ASTM C 131. The amount of flat and elongated particles shall not exceed 30 percent. A flat particle is one having a ratio of width to thickness greater than 3; an elongated particle is one having a ratio of length to width greater than 3. In the portion retained on each sieve specified, the crushed aggregates shall contain at least 50 percent by weight of crushed pieces having two or more freshly fractured faces with the area of each face being at least equal to 75 percent of the smallest midsectional area of the piece.

When two fractures are contiguous, the angle between planes of the fractures must be at least

30 degrees in order to count as two fractured faces. Crushed gravel shall be manufactured from gravel particles 50 percent of which,…