FB FHR RTA Specifications Vol 2 of 3.pdf

W912EP20R0039

Jacksonville District

Fort Buchanan Family Housing Replacement Fort Buchanan, Guaynabo, Puerto Rico

Construction Solicitation and Specifications Volume 2 of 3

Volume 2 of 3 issue date 7 October 2020

Page: 1 of 2

Date: August 2020

Project Name:

Fort Buchanan Family Housing Replacement, Guaynabo, Puerto Rico

Solicitation No.:

W912EP20R0039

Document Submittal:

RTA Submittal

Project Manager: Douglas Elledge, PE, PMP

Alain Rivard, AIA

Architect and overarching designer of record

Andrew Maginnis, PE Structural Engineer

Aaron Seal, PE Civil Engineer

08/24/20 amaginnis Stamp arivard Stamp

Francisco Gomez, PE Mechanical

Francis Oakes, PE Electrical

Jonathan Crowder, PLA Landscape Architect

Yang Lu, FPE Fire Protection

8/24/2020 ylu Stamp ylu Typewritten Text 8/24/2020 jwcrowder Snapshot fgomez Image

Fort Buchanan Family Housing Replacement Fort Buchanan Guaynabo, Puerto Rico

PROJECT TABLE OF CONTENTS

DI VI SI ON 00 - PROCUREMENT AND CONTRACTI NG REQUI REMENTS

00 10 00 SF 1442 AND BIDDING SCHEDULE

00 31 32 GEOTECHNICAL DATA

00 33 50 WEATHER AND WATER STAGE DATA

DI VI SI ON 01 - GENERAL REQUI REMENTS

01 11 00 SUMMARY OF WORK

01 14 00 WORK RESTRICTIONS AND SPECIAL PROVISIONS

01 30 00 ADMINISTRATIVE PROCEDURES

01 32 01 PROJECT SCHEDULE

01 33 00 SUBMITTAL PROCEDURES

01 33 29 SUSTAINABILITY REPORTING

01 35 26 GOVERNMENTAL SAFETY REQUIREMENTS

01 45 00 RESIDENT MANAGEMENT SYSTEM CONTRACTOR MODE (RMS CM)

01 45 04 CONTRACTOR QUALITY CONTROL

01 45 35 SPECIAL INSPECTIONS

01 50 02 TEMPORARY CONSTRUCTION FACILITIES

01 52 10 CONTRACTING OFFICER'S FIELD OFFICE

01 55 26 TRAFFIC CONTROL

01 57 20 ENVIRONMENTAL PROTECTION

01 78 02 CLOSEOUT SUBMITTALS

01 78 23 OPERATION AND MAINTENANCE DATA

01 91 00.15 TOTAL BUILDING COMMISSIONING

DI VI SI ON 02 - EXI STI NG CONDI TI ONS

02 41 00 DEMOLITION

02 82 00 ASBESTOS REMEDIATION

02 83 00 LEAD REMEDIATION

DI VI SI ON 03 - CONCRETE

03 30 00 CAST-IN-PLACE CONCRETE

DI VI SI ON 04 - MASONRY

04 20 00 UNIT MASONRY

DI VI SI ON 06 - WOOD, PLASTI CS, AND COMPOSI TES

06 10 00 ROUGH CARPENTRY

06 20 00 FINISH CARPENTRY

06 60 00 CELLULAR PVC FABRICATIONS

DI VI SI ON 07 - THERMAL AND MOI STURE PROTECTI ON

07 05 23 PRESSURE TESTING AN AIR BARRIER SYSTEM FOR AIR TIGHTNESS

07 14 00 FLUID-APPLIED WATERPROOFING

07 21 40 FOAMED-IN-PLACE MASONRY WALL INSULATION

07 22 00 ROOF AND DECK INSULATION

07 56 00 FLUID-APPLIED ROOFING

07 60 00 FLASHING AND SHEET METAL

07 84 00 FIRESTOPPING

07 92 00 JOINT SEALANTS

PROJECT TABLE OF CONTENTS Page 1

DI VI SI ON 08 - OPENI NGS

08 11 13 STEEL DOORS AND FRAMES

08 11 16 ALUMINUM DOORS AND FRAMES

08 14 00 WOOD DOORS

08 36 13 SECTIONAL OVERHEAD DOORS

08 51 13 ALUMINUM WINDOWS

08 71 00 DOOR HARDWARE

08 81 00 GLAZING

DI VI SI ON 09 - FI NI SHES

09 22 00 SUPPORTS FOR PLASTER AND GYPSUM BOARD

09 23 00 GYPSUM PLASTERING

09 29 00 GYPSUM BOARD

09 30 10 CERAMIC, QUARRY, AND GLASS TILING

09 90 00 PAINTS AND COATINGS

09 97 23 DIRECT APPLIED FINISH SYSTEM

DI VI SI ON 10 - SPECI ALTI ES

10 71 13.13 HURRICANE FABRIC

DI VI SI ON 11 - EQUI PMENT

11 31 13 ELECTRIC KITCHEN EQUIPMENT

11 68 13 PLAYGROUND EQUIPMENT

DI VI SI ON 12 - FURNI SHI NGS

12 21 00 WINDOW BLINDS

12 32 00 MANUFACTURED WOOD CASEWORK

12 36 00 COUNTERTOPS

12 93 00 SITE FURNISHINGS

DI VI SI ON 21 - FI RE SUPPRESSI ON

21 21 00 FIRE EXTINGUISHING SPRINKLER SYSTEMS (RESIDENTIAL)

DI VI SI ON 22 - PLUMBI NG

22 00 00 PLUMBING, GENERAL PURPOSE

22 07 19.00 40 PLUMBING PIPING INSULATION

DI VI SI ON 23 - HEATI NG, VENTI LATI NG, AND AI R CONDI TI ONI NG ( HVAC)

23 00 00 AIR SUPPLY, DISTRIBUTION, VENTILATION, AND EXHAUST SYSTEMS

23 05 48.19 SEISMIC BRACING FOR HVAC

23 07 00 THERMAL INSULATION FOR MECHANICAL SYSTEMS

23 09 00 INSTRUMENTATION AND CONTROL FOR HVAC

23 09 23.02 BACNET DIRECT DIGITAL CONTROL FOR HVAC AND OTHER BUILDING

CONTROL SYSTEMS

23 81 29 VARIABLE REFRIGERANT FLOW SYSTEM OUTDOOR UNIT

23 81 30 VARIABLE REFRIGERANT FLOW INDOOR SYSTEM

DI VI SI ON 26 - ELECTRI CAL

26 00 00.00 20 BASIC ELECTRICAL MATERIALS AND METHODS

26 08 00 APPARATUS INSPECTION AND TESTING

PROJECT TABLE OF CONTENTS Page 2

26 12 21 SINGLE-PHASE PAD-MOUNTED TRANSFORMERS

26 13 00 SF6/HIGH-FIREPOINT FLUIDS INSULATED PAD-MOUNTED SWITCHGEAR

26 20 00 INTERIOR DISTRIBUTION SYSTEM

26 31 00 SOLAR PHOTOVOLTAIC (PV) COMPONENTS

26 36 23.00 20 MANUAL TRANSFER SWITCHES

26 51 00 INTERIOR LIGHTING

26 56 00 EXTERIOR LIGHTING

DI VI SI ON 27 - COMMUNI CATI ONS

27 05 13.43 TELEVISION DISTRIBUTION SYSTEM

27 10 00 BUILDING TELECOMMUNICATIONS CABLING SYSTEM

DI VI SI ON 28 - ELECTRONI C SAFETY AND SECURI TY

28 31 74.00 20 INTERIOR FIRE DETECTION AND ALARM SYSTEM

DI VI SI ON 31 - EARTHWORK

31 00 00 EARTHWORK

31 31 16.19 TERMITE CONTROL BARRIERS

DI VI SI ON 32 - EXTERI OR I MPROVEMENTS

32 05 33 LANDSCAPE ESTABLISHMENT

32 18 16.13 PLAYGROUND PROTECTIVE SURFACING

32 92 19 SEEDING

32 92 23 SODDING

32 93 00 EXTERIOR PLANTS

DI VI SI ON 33 - UTI LI TI ES

33 11 00 WATER UTILITY DISTRIBUTION PIPING

33 12 33.00 30 WATER METERS

33 30 00 SANITARY SEWERAGE

33 71 02 UNDERGROUND ELECTRICAL DISTRIBUTION

33 82 00 TELECOMMUNICATIONS OUTSIDE PLANT (OSP)

APPENDICES

APPENDIX A EXCAVATION PERMIT

APPENDIX B ASBESTOS AND LEAD BASED PAINT INSPECTION REPORT

APPENDIX C GSS SUE REPORT

APPENDIX D PUERTO RICO DOT LINK

APPENDIX E SWPPP

APPENDIX F TOPOGRAPHIC PLAN AND BORING LOCATION PLAN

-- End of Project Table of Contents --

PROJECT TABLE OF CONTENTS Page 3

Fort Buchanan Family Housing Replacement Fort Buchanan, Puerto Rico

SECTION TABLE OF CONTENTS

DIVISION 00 - PROCUREMENT AND CONTRACTING REQUIREMENTS

SECTION 00 10 00

SF 1442 AND BIDDING SCHEDULE

PART 1 GENERAL

1.1 SF 1442 SOLICITATION, OFFER, AND AWARD

1.2 BID SCHEDULE

PART 2 PRODUCTS

PART 3 EXECUTION

-- End of Section Table of Contents --

DOCUMENT 00 10 00 Page 1

SECTION 00 10 00

SF 1442 AND BIDDING SCHEDULE

PART 1 GENERAL

1.1 SF 1442 SOLICITATION, OFFER, AND AWARD

See Volume 1 .

1.2 BID SCHEDULE

See Volume 1.

PART 2 PRODUCTS

Not Used

PART 3 EXECUTION

Not Used

-- End of Section --

DOCUMENT 00 10 00 Page 2

LEFT BLANK INTENTIONALLY

DOCUMENT 00 10 00 Page 3

SECTION TABLE OF CONTENTS

DIVISION 00 - PROCUREMENT AND CONTRACTING REQUIREMENTS

SECTION 00 31 32

GEOTECHNICAL DATA

06/20

PART 1 GENERAL

1.1 GEOTECHNICAL DATA

PART 2 PRODUCTS-Not Used

PART 3 EXECUTION-Not Used

-- End of Section Table of Contents --

DOCUMENT 00 31 32 Page 1

SECTION 00 31 32

GEOTECHNICAL DATA

06/20

PART 1 GENERAL

1.1 GEOTECHNICAL DATA

This Document is made available for Bidders' convenience and information.

This Document and its attachments are not part of the Contract Documents.

Because subsurface conditions indicated by the soil borings are a sampling in relation to the entire construction area, and for other reasons, the Owner, the Architect, the Architect's consultants, and the firm reporting the subsurface conditions do not warranty the conditions below the depths of the borings or that the strata logged from the borings are necessarily typical of the entire site. Any party using the information described in the soil borings and geotechnical report shall accept full responsibility for its use.

GEOTECHNI CAL REPORT ATTACHED AT THE END OF THI S SECTI ON.

PART 2 PRODUCTS-Not Used

PART 3 EXECUTION-Not Used

-- End of Section --

DOCUMENT 00 31 32 Page 2

DESPIAU ASSOCIATES

CONSULTING GEOTECHNICAL ENGINEERS

PO BOX 260370

San Juan, PR 00926-2622 www.despiau.net

U.S. Army Corps of Engineers

CONSULTING GEOTECHNICAL ENGINEERS

Report for the Geotechnical Investigation Prepared for the

Proposed Family Housing Replacement Project (Coconut Grove Site) at Fort Buchanan Military Base Facilities at the Municipality of Guaynabo, Puerto Rico.

Geotechnical Report

Job No. DA/19Y3837 Project No. W91278-18-D-0003

November 18, 2019

Prepared for:

ATKINS CARIBE, LLP

Metro Office Park, Street 1, Lot 15

4th Floor, Suite 400 Guaynabo, PR 00968

Jose R. Despiau, P.E., License #17343 Geotechnical Engineer, Despiau Associates – Consulting Geotechnical Engineers.

U.S. Army Family Housing Replacement Ft. Buchanan, Guaynabo, PR

Table of Contents Page

I. INTRODUCTION

II. SITE DESCRIPTION

III. SUBSURFACE IINVESTIGATION AND SAMPLING PROGRAM

IV. SURFACE SOIL DESCRIPTION AND GEOLOGICAL MAPPING

4.1 Surface Soils

4.2 Geological Notes

4.3 Stratigraphic Units

4.3.1 Western Sector - [Borings No. 1 to 8, 15, 18, & 19]

4.3.2 Eastern Sector - [Borings No. 9 to 14, 16, 17 & 20 to 23]

4.4 Groundwater Levels

V. SEISMIC ANALYSIS

5.5 Seismic Design Parameters

VI. ENGINEERING RECOMMENDATIONS

6.1 Engineering Assessments

6.2 Complete Removal and Replacement Alternative

6.2.1 Extent of Removal of Unsuitable Material at the Site

6.2.2 Demucking and Fill Embankment Considerations

6.2.3 Foundation Design Recommendations for a Complete Demucking Operation

6.2.4 Deep Fill Delay Stabilization Program

6.3 Soil improvement using Geogrids

6.3.1 Reinforced Fill Embankment using Geogrids

6.3.2 Foundation Recommendation for Reinforced Embankments with Geogrids

6.4 Additional Foundation Considerations

6.5 Groundwater Considerations

6.6 Pavements

6.7 Nearby Structures

6.8 General Earthwork Recommendations

6.8.1 Excavations

6.8.2 Temporary Cut Sections

6.8.3 Backfill Material

6.8.4 Demolition

6.9 Proposed Storm Water Run-off Control

6.10 Additional Recommendations

VII. LIMITATIONS OF THIS REPORT

Appendix (A) – Figures

1. US Geological Survey Service Topographical plan at a scale 1:20,000 1A. Geological Map

2. Boring Location Plan

3. Figures 3 – Site with Sectors Identified

Appendix (B) - Boring Logs Appendix (C) - Special Laboratory Tests

Appendix (D) - Fill Specifications

I. INTRODUCTION

This report covers the Subsoil Exploration and Geotechnical Engineering Services for the

Proposed Family Housing Replacement Project (Coconut Grove Site) at Fort Buchanan Military

Base Facilities at the Municipality of Guaynabo, Puerto Rico.

The work was undertaken at the request of Francisco Pérez Aguiló, MS, REM - Senior Project

Manager, Principal of Atkins Caribe, LLP, in accordance to the Proposal No. DA/06-06-19 for the subsurface exploration dated June 20, 2019. The work was commenced after order to proceed and fully executed contract was received on August 20, 2019.

This report presents the results of the field exploratory drilling, laboratory tests performed on secured soil samples, engineering analyses, summary of findings, and foundation recommendations to assist the A/E design team in the site engineering design, preparation of cost estimates, to be used for the proposed Family Housing Replacement Project.

The presently design scheme the proposed family housing replacement project entails the following facilities:

1. Twenty-six (26) Residential Dwelling Units

2. Residential Development Site Design

3. Outdoor Recreational Open Space Park

The selected boring locations were used to establish the general profile data of the Site for the present geotechnical engineering review. This report has been prepared for the exclusive use of the Owner and the A/E Consultant Firm involved in the preparation of the site engineering design plans and specifications.

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U.S. Army Family Replacement Project Page 2

II. SITE DESCRIPTION

The site of the proposed housing replacement project is located to the westernmost sector of the

Existing Fort Buchanan Military Base. Fort Buchannan Army installation is located within the municipalities of Bayamón and Guaynabo to the west of San Juan.

The proposed housing development area is approximately, 15.5 acres to the westernmost sector of

Fort Buchanan. Specifically, the proposed Coconut Grove new housing development area is located to the east of the Perimeter Road, south of Howze Drive, west of Seagrape Street, and south of Flamboyan Street. Presently, twenty-six (26) old residential dwelling units exist, which shall be demolished to allow the construction of twenty-six (26) new residential dwelling units.

The site is on relatively flat lands which were brought to the existing grade during the original

Coconut Grove development, varying between 72.46 [Boring 3] to 55.64 [Boring 22] feet in elevations. The proposed development area is a lowland sector within the western sector of the

Military facilities. To the south-southwest of the proposed development area is bordered by multiple haystack hills exist, at about 230.0 ft in elevation, therefore all surface runoff from the south-southwest shall drain toward the east-northeast of lower elevation to the proposed development.

Based on the grading plans submitted for the present evaluation, the grading requirements, shown in Table No. 1, will be required for the proposed development.

TABLE 1 – SUMMARY OF GENERAL GRADING DATA AND REQUIREMENTS

Boring No.

Proposed Structure

Approx.

Existing Elevation

(ft.)

Approx.

Proposed Elevation

(ft.)

Cut /Fill

Amount

Comments

1 Res. Dwelling 57.350 57.200 Cut (0.150) * Over excavation

2 Res. Dwelling 66.700 64.500 Cut (2.200) * Over excavation

3 Res. Dwelling 72.460 70.000 Cut (2.460) * Over excavation

4 Res. Dwelling 68.040 69.700 Fill 1.660 * Over excavation

5 Res. Dwelling 67.390 67.700 Fill 0.310 * Over excavation

6 Res. Dwelling 72.440 70.850 Cut (1.590) * Over excavation

7 Res. Dwelling 63.610 64.500 Fill 0.890 * Over excavation

8 Pavement 70.990 71.760 Fill 0.770 * Over excavation

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Table 1 - Continue

Boring No.

Proposed

Approx.

Existing Elevation

(ft.)

Approx.

Proposed Elevation

Cut /Fill

Amount

Comments

9 Res. Dwelling 72.210 71.800 Cut (0.410) * Over excavation

10 Res. Dwelling 67.650 66.650 Cut (1.000) * Over excavation

11 Res. Dwelling 68.960 68.400 Cut (0.560) * Over excavation

Recreational

Area 70.500

70.450 Cut (0.050)

* Over excavation

13 Res. Dwelling 60.100 60.200 Fill 0.100 * Over excavation

Recreational

Area 64.140

62.400 Cut (1.740)

* Over excavation

15 Pavement 68.110 69.900 Fill 1.790 * Over excavation

16 Res. Dwelling 62.100 61.500 Cut (0.600) * Over excavation

17 Res. Dwelling 62.960 61.950 Cut (1.010) * Over excavation

18 Pavement 64.830 65.900 Fill 1.070 * Over excavation

19 Pavement 67.120 68.000 Fill 0.880 * Over excavation

20 Pavement 72.080 72.000 Cut (0.080) * Over excavation

21 Pavement 60.300 60.000 Cut (0.300) * Over excavation

22 Res. Dwelling 55.640 56.900 Fill 1.260 * Over excavation

23 Pavement 65.320 67.250 Fill 1.930 * Over excavation

NOTE: * An over excavation to obtain a minimum fill thickness of 1.2 meters shall be required, however if the fill thickness exceeds 1.5 meters the expansive in-situ stiff clay can remain.

III. SUBSURFACE IINVESTIGATION AND SAMPLING PROGRAM

The subsurface soil conditions at the site were investigated via twenty-three (23) standard penetration test borings performed to assess the existing subsoil conditions at the site. The location of borings is shown in the accompanying Boring Location Plans, in Appendix A, Figure No.

2 at the end of this report.

The borings were staked out at the field and their location were recorded by Atkin’s surveying team. Then, a Subsurface Utility Clearance Survey was performed at all twenty-three (23) boring locations to assure no underground utilities were affected during the drilling field operations.

During the subsurface utility clearance survey several underground utilities were detected on nine

Project No.: DA/19Y3837 Guaynabo, Puerto Rico November 18, 2019

U.S. Army Family Replacement Project Page 4

(9) of the original proposed drilling locations, therefore these were drilling locations were relocated as shown in Figure No. 2 of Appendix A.

Sampling of soils was performed continuously in the upper 10 ft. and thereafter, at approximately five-foot intervals. Most soil samples were taken with a 2"-O.D. split barrel sampler following the standard penetration test procedures in ASTM D-1586, D-1552, & D-2113. Penetration resistance values from the standard penetration tests are recorded in the "N" column of the boring logs. Also, ten (10) undisturbed soil samples were obtained with thin-walled Shelby tubes.

The procedures used for the laboratory tests, as well as the routine and special laboratory procedures used, for the determination of the index soil properties are contained in the Appendix

(B) to this report.

IV. SURFACE SOIL DESCRIPTION AND GEOLOGICAL MAPPING

4.1 Surface Soils

The US Soil Conservation Service Manual – Soil Survey of the San Juan Area of Puerto Rico, Map

#8, prepared by the Soil Conservation Service identifies the surface soils at the site and its vicinity as follows:

• Almirante clay, 2 to 12 percent slopes (AmC, AmB) – These soils are gently sloping, well-drained soil on coastal plains and valleys between limestone hills.

Typically, the surface layer is dark yellowish brown, friable clay about 7 inches thick.

The subsoil is firm clay to a depth of 60 inches. From 7 to 34 inches, it is strong brown; from 34 to 46 inches, it is brownish yellow and dark red; and from 46 inches to

60 inches, it is variegated brownish yellow, dark red, and light gray.

They are characterized by their moderate permeability and available water capacity.

Runoff is medium. This soil is difficult to work due to stickiness and plasticity of the clay and shrink-swell potential. Controlling erosion is a major concern of management. These soils are limited from most urban uses because of its clayey nature.

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• Tanamá-Rock outcrop complex, 20 to 60 percent slopes (TaF) – This complex consists of steep to very steep, hollow, well drained Tanamá soils and Rock outcrop.

This complex has formed in karst topography characterized by pepino or haystack hills as those found to the south-southwest of the site. The topography is very rugged and slopes in many directions. The irregular topography has been formed by the solutional destruction of the dense, thin bedded limestone. Most areas are asymmetrical and range from 25 to 300 feet in height. This complex is about 45 percent Tanamá soils, 40 percent Rock outcrop, and 15 percent minor soils.

In a representative profile of Tanamá soils the surface layer is dark reddish brown, friable clay about 4 inches thick. The subsoil is about 10 inches thick; it is reddish brown, firm clay. Hard semi consolidated limestone is at a depth of 14 inches.

The Tanamá soils is characterized by its rapid runoff, erosion (severe), moderate permeability and low available water capacity. These soils are difficult to work because it is steep to very steep and because it is intertongued with Rock outcrop.

This complex is moderately limited for most urban uses mainly because of the slopes, rock outcrops, and shallow depth to rock.

4.2 Geological Notes

The units that outcrop in the vicinity of the site are shown in the US Geological Survey Map of the

Bayamón Quadrangle (Map I-751), as prepared by Watson H. Monroe (1973). These units are as follows:

• Mucarabones sand (Tm) – The Mucarabones sand is described as grayish-orange to yellowish brown cross-bedded medium to coarse calcareous sand. In areas, part of the Cibao Formation, intertongued and grade laterally eastward into the

Mucarabones sand. In Bayamón the lower part of the sand, resting sharply on the

San Sebastián Formation, consist of grayish-orange to dark-yellowish-orange clayey medium to coarse sand. Still farther east, the lower part of the formation consists of crossbedded coarse quartz sand containing lenses of subangular to subrounded gravel and lenses of greenish-gray sandy clay.

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Scattered through the middle and upper parts of the formation, lenses of sandy limestone and very pale orange to grayish-brown sandy clay both, richly fossiliferous exist.

• Alluvium (Qa) – To the north of the site alluvium deposits have been identified as sand, clay, and sandy clay; beds of sand containing gravel and cobbles were identified in valleys. Farther to the north beyond Fort Buchanan premises, on the seaward parts of the valleys of the Rio Bayamón and the Río de la Plata are apparently deltas of the two rivers which built out into a lagoon now filled in by alluvium to form the large swamps in the northern part of the quadrangle.

• Cibao Formation, upper member (Tcu) – Described as chalk, soft limestone, and very pale orange sandy clay. Upper part intertongued with Aguada Limestone in west quarter of quadrangle. Lower part grades laterally into Mucarabones Sand.

• Aguada Limestone (Ta) – Described as alternating thick beds of indurated very pale orange to pink fine calcarenite and grayish-orange to very pale orange clayey and chalky limestone containing scattered grains of quartz; locally fossiliferous. In the map area both upper and lower contacts appear to be gradational, except in the western part where the top of the formation contains abundant thin-bedded limestone.

At the west edge of the quadrangle about 70 m thick. The lower, more sandy and clayey part of the Aguada intertongued with the Cibao Formation between Toa Alta and Bucarabones, and farther east, the formation is only about 35 m thick.

• Landslide deposits (Ql) – Described as masses of soil, calcareous clay, and limestone rubbles, containing blocks of limestone as long as 25 meters.

4.3 Stratigraphic Units

For simplicity purposes the site has been divided into two (2) sectors, the following sections of this report described the general stratigraphy of both western and eastern sectors, respectively. Figure

No. 3 of Appendix A illustrated an imaginary line which divides the project into these two sectors.

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4.3.1 Western Sector - [Borings No. 1 to 8, 15, 18, & 19]

At the westernmost project sectors, beneath the surface topsoil layer, exhibiting few to many roots, it was found a surface modified fill layer of silty clay with variable amounts of sand, and occasional angular gravel fragments. The most prominent colors were the dark brown, yellow brown, yellow red and light gray. The surface layer extends to an average depth of 5.0 ft. The standard resistance to penetration (N-values) varies from 5 to 31 blows/foot, at a medium to hard State of

Consistency. The natural moisture content values range from 8 to 38 percent. The unconfined compressive strength (qu) values range from 0.9 to 3.2 tons/sq. ft.

Random samples from this surface layer disclosed A-6, A-7-5 and A-7-6 AASHTO type (CL and

CH soils, as per USCS) with percent free swell values ranging between 15 and 55%. The clay type soils were identified as Interstratified and Montmorillonite exhibiting high expansive characteristics.

Below the surface modified clayey fill section, the alluvial deposit described as pale yellow, brownish yellow, red and light gray silty clay, trace sand was found. This intermediate layer extends to an average of 9.0 ft. in depth. The standard resistance to penetration (N-values) varied from 7 to 40 blows/foot at a medium to hard State of Consistency. The natural moisture content values range from 17 to 40 percent. The unconfined compressive strength (qu) values range from

0.5 to 3.0 tons/sq. ft.).

Following the upper soil, the residual layers were encountered. These were described as light gray, brownish yellow, olive yellow, and light gray with black secondary structures with black in joints consolidated sandy silt, clayey silt, and silty clay. This consolidated residual layer extends to an average of 18.5 ft. in depth. The standard resistance to penetration (N-values) varied from 10 to

47 blows/foot.

Extending to the depth at which the borings were bottomed, the completely weathered rock from the upper member of the Cibao Formation was found. The material was generally described as very pale brown, pale yellow, light yellow brown, red and white sandy silt with variable amounts of clay and calcareous rock fragments. The standard resistance to penetration (N-values) varied from

23 to 89 blows/foot and practical refusal to penetration was obtained at the deeper levels of

Project No.: DA/19Y3837 Guaynabo, Puerto Rico November 18, 2019

U.S. Army Family Replacement Project Page 8 exploration [Boring No. 1 to 11], with values in excess of 60 blows for a few inches of penetration.

The natural moisture content values range from 11 to 13 percent.

4.3.2 Eastern Sector - [Borings No. 9 to 14, 16, 17 & 20 to 23]

At the easternmost project sector, beneath the surface topsoil layer exhibiting few to many roots at ground surface, it was found a surface modified fill layer of silty clay with variable amounts of sand, and occasional angular gravel fragments. The most prominent colors were the dark brown, yellow brown, yellow red and light gray.

This surface layer extends to varying depths of 1.5’ to 6.0 ft. Standard resistance to penetration

(N-values) varying from 5 to 57 blows/foot, at a medium to hard State of Consistency were obtained. The natural moisture content values range from 2 to 48 percent (Saturated w % >35 %).

The unconfined compressive strength (qu) values range from 0.8 to 2.2 tons/sq. ft.

Random samples from this surface layer disclosed A-7-5 and A-7-6 AASHTO type (CH soils, as per USCS) with percent free swell values ranging between 45 and 55%. The clay type soils were identified as Montmorillonite exhibiting very high expansive characteristics.

Below the surface modified fill and alluvial soil deposits, described brown, brownish yellow, red, and light gray, with mottles yellow and brown silty clay, with varying amounts of sand and subangular gravel or calcareous rock fragments, were found. This intermediate layer extends to an average of 9.0 ft. in depth. The standard resistance to penetration (N-values) varied from 11 to

27 blows/foot at a stiff to very stiff State of Consistency. The natural moisture content values range from 18 to 41 percent (Saturated w % >35 %). The unconfined compressive strength (qu) values range from 1.2 to 3.7 tons/sq. ft.).

Following the upper soils, the residual layers were encountered. These were described as light gray, brownish yellow, olive yellow, and light gray with black secondary structures with black in joints consolidated sandy silt, clayey silt, and silty clay. This consolidated residual layer extends to an average of 18.5 ft. in depth. The standard resistance to penetration (N-values) varied from 7 to

47 blows/foot. At the location of Boring No. 13, a 1.0 ft. void or cavity was detected at a depth of

18.5 ft. This void is typically caused by the dissolution of the calcareous limestone of the Cibao

Formation.

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Deeper into the profile, extending all the way up to the depth drilled, the completely weathered from the parent Cibao Formation, material was encountered. The standard resistance to penetration (N-values) varied from 21 to 57 blows/foot and practical refusal to penetration was obtained at the deeper levels of exploration, with values in excess of 60 blows for a few inches of penetration. The natural moisture content values range from 10 to 35 percent.

The graphical representation of the soil profiles is found in the boring logs included as Appendix

(B) to this Report.

4.4 Groundwater Levels

In general, the ground water level was not found within the extent of depth of the borings of exploration. However, at the location of Boring No. 16, the ground water was found at a depth of

20.0 ft., beneath the existing ground surface prevailing during the period of the field work.

The prevalent subsoil profile may cause hydrostatic pressure problems due to water ponding of the low permeability of the in-situ soil. Therefore, special measures shall be taken (i.e.

underdrains) to relieve any hydrostatic pressure beneath any underground structure (i.e. cisterns, basements, etc..), if any. As a minimum, perimetral drains shall be provided any new structure to allowed to divert any surface and subsurface water which may seep beneath the structure, causing hydrostatic pressures due to the low permeability clayey material found at the site.

The groundwater level was measured after completion of the borings, during the period of the field work. All surface ground and underground water should flow from the higher sectors at the south-southwest toward the project areas of lower elevations.

V. SEISMIC ANALYSIS

5.5 Seismic Design Parameters

Based on our experience with the geology of the area, it is our opinion that the subsurface

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U.S. Army Family Replacement Project Page 10 characteristics reflect those of Site Class D as described in International Building Code 2018 and the Puerto Rico Building Code 2018. The “Site Class” is a designation used by the 2018

International Building Code (IBC) (ICC 2018) to quantify ground motion amplification.

The classification is based on the stiffness in the upper 100 feet of soil and bedrock materials of the site. Although we performed all SPT Borings up to 25 feet in depth, based on our exploratory borings and experiences at the Site’s vicinity, and considering the herein proposed improvements, leads us to classify the site as Site Class D.

The IBC indicates that sites classified as Site Class D or E with S1 greater than 0.2 a site‐specific ground response analysis be completed to determine the response spectrum for design as per

Section 11.4.8 of ASCE 7. We anticipate seismic design parameters may change if a site‐specific ground response analysis is completed; therefore, the parameters provided in the following Table, presents the parameters obtained from the building code and the resulting values for SDS and

SD1, respectively.

Table 2 - Seismic Design Parameters

Parameter MCER

Site Class D

Risk Category II

Spectral Response Acceleration (Short Period), Ss 0.984 g

Spectral Response Acceleration (1-Second Period), S1 0.386 g

Site Coefficient, Fa 1.106

Site Coefficient, Fv 1.629

Modified Spectral Response Acceleration (Short Period), SMS 1.089

Modified Spectral Response Acceleration (1-Second Period), SM1 0.628

Spectral Response Acceleration (Short Period), SDS 0.726

Spectral Response Acceleration (1-Second Period), SD1 0.419

VI. ENGINEERING RECOMMENDATIONS

6.1 Engineering Assessments

Based on the subsurface profile obtained, unsuitable saturated expansive sandy fat clays were

Project No.: DA/19Y3837 Guaynabo, Puerto Rico November 18, 2019

U.S. Army Family Replacement Project Page 11 found to exist all throughout the complete extent of the proposed residential development. The extent of the surface unsuitable material varied between 0.0 to 6.0 ft., 4.5 ft. in average. Moreover, classification tests performed revealed the surface sandy fat clays (A-7-6 AASHTO type / CH -

Sandy Fat Clay, as per USCS) material, found throughout most of the tract of land, exhibit a very high shrink/swell potential.

Thus, the complete removal and replacement of any unsuitable oversaturated highly expansive surface material shall be allowed to cast the proposed foundation over a compacted engineered fill section. However, considering the extensive earthwork required to allow the complete removal operation (varying between 4.0 to 6.0 ft. in depth), an alternate soil reinforcement technique using

Geogrids may be considered on the eastern sector of the proposed development to cope with the expected settlements beneath the proposed residential dwelling units.

In conclusion, two soil improvement alternative may be considered by the A/E design team for the proposed development. These are the following:

1. Complete removal and replacement, with an earth fill material shall be of A-2-4 or better

(AASHTO type) compacted to not less than 95% of its maximum dry density, as per the

Modified Proctor Test. This alternative will entail the removal of any soft to medium unsuitable expansive clay material which thickness varies between 0.0 to 6.0 ft., 4.5 ft. in average. This alternative may be considered on both sectors of the project (eastern and western sectors).

Or

2. Soil reinforcement using Geogrids. This stabilization technique uses geogrids to maintain the imparted stresses within the upper horizon of the existing fill section and to redirect horizontally the expected stresses. Under this alternate stabilization scheme, the new residential dwelling units may also consider a raft type foundation, however a reduced allowable soil bearing capacity shall be considered by design. This alternative may be considered on the eastern sector of the project where the extent of removal is deeper into the stratum. The eastern sector is identified on the Figure No. 3 of Appendix A, where

Borings No. 9 to 14, 16, 17 & 20 to 23 were drilled. Although this alternative may be also considered for the western sector, it is our opinion the first alternative presented would be a

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U.S. Army Family Replacement Project Page 12 more cost effective approach.

The following sections of this report will further discuss this alternatives as well as to provide the foundation design recommendation to be considered with either of the proposed alternatives.

6.2 Complete Removal and Replacement Alternative

To cope with the unsuitable saturated expansive sandy fat clays found throughout most of the site, the complete removal and replacement of any unsuitable material shall be allowed to cast the proposed foundation over a compacted engineered fill section. Therefore, as part of the earthwork phase of construction, it is necessary to pre-treat the existing soils. Thus, following construction stages shall be considered:

1. Once the surface unsuitable material (surface vegetative cover) as well as any remnant of organic soils, construction debris, and/or expansive plastic clays which may be found are completely removed, the permanent fill layers shall be deposited in stages.

2. The earth fill material shall be of A-2-4 or better AASHTO type, compacted to not less than 95% of its maximum modified dry density test. A-1-a fill type is recommended to be deposited at the flood susceptible zones, if any.

6.2.1 Extent of Removal of Unsuitable Material at the Site

At most of the explored locations, unsuitable saturated highly expansive sandy fat clays were found to exist on the upper surface layers. Therefore, the complete replacement, with granular non-expansive fill material shall be allowed to cope with the in-situ soil expansive characteristics.

The extent of the surface unsuitable material varied between 4.0 to 6.0 ft. in thickness, 4.75 ft.

average.

The minimum extent of removal is summarized in the following Table 3. However, the actual extent of removal shall be determined at the field by the inspecting soils engineer.

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U.S. Army Family Replacement Project Page 13

Table 3 - MINIMUM DEPTH OF REMOVAL

Western Sector *

Boring No.

Minimum Removal

Depth (ft.)

1 4.0

2 5.0

3 5.0

4 4.0

5 4.5

6 4.0

7 4.0

8 4.5

15 4.0

18 4.5

19 4.5

Eastern Sector

Minimum Removal

Depth (ft.)

9 4.0

10 6.0

11 6.0

12 6.0

13 4.0

14 6.0

16 4.5

17 4.0

20 Abandoned*

21 4.0

22 6.0

23 4.0

*NOTE: Boring No. 20 was abandoned due to unknown obstruction, possibly an underground utility. Concrete was encountered at depth of 1.0 ft. in depth.

On the westernmost sector of the project, solely, in lieu to the complete replacement a partial removal of the surface expansive clays to a minimum depth of 4.0 ft. can be allowed. However, a proof rolling of the exposed surface shall be performed to detect any soft spots, which shall be removed and replaced entirely. Once these are removed, the daylighted soil shall be recompacted to a minimum 95 % of its maximum dry density. Thereafter, the permanent fill layers shall be deposited in stages as previously described.

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U.S. Army Family Replacement Project Page 14

6.2.2 Demucking and Fill Embankment Considerations

Laboratory tests performed on random secured samples, revealed saturated expansive unsuitable material (A-7-6 AASHTO type / CH - Sandy Fat Clay, as per USCS). These high plasticity sandy fat clays are very difficult to work with due to its capacity to retain moisture and its high plasticity. It is well known in the construction industry, these soils present setbacks, during earthwork, when trying to obtain the required compaction effort (95 % of its maximum dry density) and required moisture conditions. Therefore, they shall be disposed or save to be used on green areas, SOLELY. By NO MEANS, the in-situ soil shall be used as backfill and/or to erect any slope at the

Site. Neglecting to follow this important aspect of construction may lead to future embankment instability.

Although not predicted, should large boulder and cobbles be found during the earthwork phase of construction, these will need to be reduced in size prior to be reused as backfill material or hauled off site. Also, any debris (i.e foundation, underground utilities, etc..) from previous demolished structures shall be removed entirely prior to any fill placement at the site.

Due to the aforementioned circumstances, granular non-expansive borrow fill (A-2-4 or better

AASHTO type) shall be required all-throughout the project. Any soil to be used as backfill material shall be taken to a soil’s laboratory prior to its use; to confirm the material complies with project’s specifications (A-2-4 of better AASHTO type).

The following construction stages shall be considered during the design and construction processes. These are:

1. All permanent fill layers shall be deposited in stages, after the surface unsuitable material (i.e. surface vegetative cover, construction debris, etc...) and any remnant of unsuitable expansive clays and/or debris from previous structures have been removed.

The minimum depth of removal shall be as indicated in Table 3 of the previous section of this report, unless the alternate partial removal alternative be selected by the A/E design team.

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U.S. Army Family Replacement Project Page 15

2. A uniform thickness beneath the footprint of any structure shall be provided. In any case, the difference in the total fill thickness beneath any structural unit, as established by the structural designer, shall not exceed 1.0 meters (3.28 ft.).

3. Special care shall be taken to avoid any cut/fill circumstances within the footprint of any structure. Should the project’s grading plans require this condition within any structure

(i.e. residential dwelling unit, pavement, infrastructure facilities, etc.) then, an over excavation shall be performed to allow a uniform fill section under any structure to be erected.

4. Whenever the fill thickness exceeds 3.0 meters (10.0 ft.) the proposed development shall be treated with an alternate scheduling construction scheme, considering a delay stabilization program. Although not predicted to occur, additional considerations for a delay stabilization program is further discussed in Section 6.2.4 Deep Fill Delay

Stabilization Program of this report.

5. All fill and cut slopes shall be constructed at a maximum slope ratio of 2.0H: 1.0V

(Horizontal: Vertical).

6. All borrow materials shall be taken to a soil’s laboratory for testing and approval prior to their use at the project. The in-situ soil SHALL NOT be used as backfill material.

All fill material, including pavement sectors, shall also comply with AASHTO A-2-4 or better classification and shall be compacted in layers not to exceed 6” to 10” inches, when compacted, to not less than 95% of the Modified Proctor Density. The fill specifications (Appendix 2) with the recommended Fill Specifications at the end of this report.

Any new ground floor slab of the structures shall be casted over a well-engineered fill material, following the standard specifications for fill construction, contained in Appendix II to this report.

6.2.3 Foundation Design Recommendations for a Complete Demucking Operation

Following the previously recommended earthwork process, which includes the replacement of all unsuitable material (i.e. soft and/or with highly expansive characteristics), the proposed Single-

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U.S. Army Family Replacement Project Page 16 family residential Units may consider the use of a mat type of foundation to support the New

Structure loads.

The foundations design of the proposed residential structures shall consider an allowable soil bearing pressure of 2.0 K/sq.-ft. to be assigned to the newly deposited compacted earthfill material.

Also, the mat foundation can be designed following the beam elastic foundation approach. For such purposes, rafts casted over the properly compacted engineered fill material, can be designed using a Modulus of Sub grade Reaction of 105 lbs./sq.-inch/inch at a minimum depth of foundation shall be 1.5 ft., below the final grade to be established.

The following Table 4 present a summary of the foundation design parameters to be used for the design of the proposed residential development under the soil replacement alternative.

TABLE 4 – SUMMARY OF FOUNDATION RECOMMENDATIONS

Identification

Allowable Soil Bearing

Pressure (ksf.)

Modulus of Subgrade Reaction Kv (lbs./sq.-in/in.)

Minimum Depth of foundation below the final grade (ft.)

Residential Dwelling

1 through 23 2.0 ksf. 105.0 @ 1.5 ft.

All fill material shall be controlled fill (AASHTO Classification A-2-4 or better), compacted to not less than 95 % Modified Proctor Density. For controlled fill, it is meant to place the fill layers in 6 to

10” inch lifts, each layer compacted to not less than 95% Modified Proctor Density.

Also, a uniform fill section is required, for which the expected fill section may increase even more.

This is to assure the differential settlements are maintained within tolerable limits for the structural building unit. Therefore, IN NO CASE shall a cut/fill scenario within the footprint of any structure shall be allowed.

6.2.4 Deep Fill Delay Stabilization Program

As previously mentioned, the subsoil exploration performed disclosed unsuitable soft to medium expansive clay material all-throughout the project. Therefore, the complete removal and

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U.S. Army Family Replacement Project Page 17 replacement of the unsuitable fill section with a controlled engineering fill section shall be allowed, unless a soil reinforcement with geogrids is used.

Although not predicted, whenever the fill thickness is greater than 3.0 meters (should this circumstances arise) the proposed development shall be treated with an alternate scheduling construction scheme, considering a delay stabilization program.

The program shall include the installation of monitoring stations with settlement platforms, which shall be monitored until the complete stabilization of the deep fill section (3.0 meters or greater in thickness) is completed.

The delay in the construction schedule is necessary to assure readjustment of the compacted deep fill section, due to its own weight and percolating water. The delay period shall be considered as a general guideline for the project to assure the deep fill sections has been stabilized completely.

The installation of settlement platforms to monitor settlements shall be installed once the complete removal is completed and prior any backfill is placed.

The stabilization time required will depend on the actual amount of fill thickness. Regardless, actual time shall be determined based on the results of the monitoring of the proposed settlements plates to be installed at the field. The program shall be in place until stable conditions are met.

Precise level surveys shall be made, considering vertical elevation data with measurements to a

0.001 precision. The data shall be obtained weekly for the first month and bi-weekly thereafter, until five (5) consecutive readings show settlement variations not greater than 0.5 mm.

6.3 Soil improvement using Geogrids

Based on the results on the exploratory program performed, it is evident that the site is underlain by a deep and unsuitable oversaturated expansive material with depth ranging from 4.0 to 6.0 ft. in depth (4.75 ft. average) for which the complete removal shall be allowed. However, considering the extensive earthwork required to allow the complete replacement operation all-throughout the project, an alternate soil improvement technique using Geogrids to cope with the expected settlements beneath the proposed residential dwelling units may be considered by design. This alternative may be considered on the eastern sector of the project (as previously described) where

Project No.: DA/19Y3837 Guaynabo, Puerto Rico November 18, 2019

U.S. Army Family Replacement Project Page 18 the extent of removal is deeper into the stratum. Although this alternative may be also considered for the western sector, it is our opinion the first alternative presented (complete replacement) would be a more cost-effective approach.

This alternate soil improvement technique involves reinforcing the backfill material with layers of geogrids, to maintain the imparted stresses within the upper horizon of the existing fill section and to redirect horizontally the expected stresses. Therefore, the demucking operation past the upper

1.2 meters would not be required. Under this alternate stabilization scheme the new residential dwelling units shall also be founded over a raft foundation, however the allowable soil bearing capacity will differ from that previously recommended. Therefore, the proposed residential dwelling units shall be founded over a doubly reinforce mat foundation complimented by a reinforced soil embankment using geogrids. The raft foundation design parameters to be considered for this alternatives are presented in a subsequence section of this letter.

6.3.1 Reinforced Fill Embankment using Geogrids

As mentioned earlier, the residential dwelling unit lot’s subsurface conditions shall be improved with a reinforced soil embankment using geogrids. Therefore, the following construction sequence shall be allowed prior to the construction of the required mat foundation. These are:

1. Once the final grade elevation is reached, a partial removal of any unsuitable under soil shall be allowed, 1.2 m. minimum, measured from the final grade to be established. The horizontal extent of the demucking operation shall extend to a minimum of 2.0 time the excavation depth on all sides of the excavation, without encroaching any existing structures. It is of utmost importance to protect any existing structures close to the excavations to prevent any lateral yielding. Zero tolerance of displacement shall be guarantee.

2. At the bottom of the temporary excavated section, a Heavy-Duty Stabilization

Fabric (TerraTex WTEC-HD or similar) shall be provided with a layer of Tensar

Triax, TX 190 (or similar) geogrids reinforcement directly on top.

3. Then, a layer of a minimum of 0.45 mts of bluish gray clean crushed stone (with diameter ranging between 4” to 6” inches) shall be deposited until an initial

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U.S. Army Family Replacement Project Page 19 stabilization is attained. Then, another layer of the same (Geogrid Tensar Triax, TX 190 or similar) shall be provided on top of the first 0.45 mts. layer.

Subsequently, a separator geotextile between the coarse aggregate (crushed-stone) and the A-2-4 material (finer) shall be provided to prevent the intrusion of any fine particles.

Once the additional separator geotextile and geogrid is placed, another layer, 0.30 mts., thick of Granular Backfill AASHTO A-2-4 or better, compacted to a minimum

95 % of its Modified Proctor Density Test shall be place and compacted on top.

This procedure shall be repeated until reaching 18” beneath the final grade to be established to allow the construction of the specified double reinforced mat foundation (Df = 1.5 ft.) as per design.

4. Afterward, the remaining backfill material, if any, may be laid as required by design

(Granular Backfill AASHTO A-2-4 or better, compacted to a minimum 95 % of its

Modified Proctor Density Test).

All stabilization fabrics and geogrids (i.e. TerraTex, Tensar or equivalent), shall continue vertically on the sides of the open excavation to a minimum distance of twice (2) the backfill layer thickness.

Also, all borrow materials shall be taken to a soil’s laboratory for testing and approval prior to their use at the project.

6.3.2 Foundation Recommendation for Reinforced Embankments with Geogrids

The proposed residential dwelling units of the project shall be founded on a doubly reinforce mat type of foundation over the compacted engineered fill section. Obviously, following the soil improvement procedures described on the previous section of this report.

The foundations design of the of the doubly reinforced mat shall consider an allowable soil bearing pressure varying from 2,250 lbs/sq.-ft. at minimum foundation depths of 1.5 ft. The depth of foundation (Df.) shall be measured from the final grade to be established. For the elastic foundation design the Modulus of Subgrade Reaction of between 125 lbs./sq.-inch/inch shall be considered.

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U.S. Army Family Replacement Project Page 20

Under the soil improvement scheme presented in the previous sections of this report the expected settlements can be tolerated by the proposed One-story, single-family structures of development, provided the control of the engineering earthwork construction process is made in accordance to specifications to be contained in the geotechnical report.

6.4 Additional Foundation Considerations

Although not predicted, should any proposed foundation unit may lie close to sloping grounds surfaces, the depth of foundation on these circumstances shall be compatible with a minimum depth requirement such that a line drawn from the bottom edge of the foundation at an angle () of

30⁰ and at a horizontal distance (t) of 15 ft. do not intersect with the face of the slope. Refer to the following Figure A.

FIGURE A: Footing in Sloping Grounds

NOTE: The footing depth on sloping grounds shall satisfy a minimum separation…