Industrial_Facility_and_Mobile_Boat_Hoist_-_PSI_Geotech_Report.pdf

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TABLE OF CONTENTS

PAGE NO.

PROJECT INFORMATION

PROJECT AUTHORIZATION

PROJECT DESCRIPTION

PURPOSE AND SCOPE OF SERVICES

SUBSURFACE CONDITIONS

BORING LOCATIONS AND SUBSURFACE CONDITIONS

DOUBLE RING INFILTROMETER TESTS

GROUNDWATER INFORMATION

FOUNDATION RECOMMENDATIONS

GEOTECHNICAL DISCUSSION

SITE PREPARATION – NEW BUILDING ADDITION

PILE FOUNDATION RECOMMENDATIONS

FLOOR SLAB RECOMMENDATIONS

BULKHEAD RECOMMENDATIONS

SHEET PILE WALL ANALYSES

ANCHORAGE SYSTEM

GLOBAL STABILITY ANALYSES

PAVEMENT RECOMMENDATIONS

CONSTRUCTION CONSIDERATIONS

MOISTURE SENSITIVE SOILS/WEATHER RELATED

DRAINAGE AND GROUNDWATER CONCERNS

EXCAVATIONS

REPORT LIMITATIONS

APPENDIX A

BORING LOCATION PLAN ...................................................................................................................................................................... PLATE A-1A CBR AND INFILTROMETER TEST LOCATION PLAN ................................................................................................................................ PLATE A-1B LOGS OF BORINGS ........................................................................................................................................................ PLATES A-2 THROUGH A-9 KEY TO TERMS AND SYMBOLS USED ON THE LOGS ............................................................................................................................. PLATE A-10 GENERALIZED SOIL PROFILE ................................................................................................................................................................ PLATE A-11

APPENDIX B

STANDARD PROCTOR & CBR TEST RESULTS ..................................................................................................................... PLATES B-1 THRU B-4 DOUBLE RING INFILTROMETER TEST RESULTS ...................................................................................................................... PLATES B-5 AND B-6

APPENDIX C

ULTIMATE AXIAL PILE CAPACITIES – PROPOSED BUILDING ADDITION

AUGER CAST-IN-PLACE PILES....................................................................................................................................... PLATES C-1A AND C-1B DRIVEN SQUARE PRECAST CONCRETE PILES ............................................................................................................... PLATES C-2A AND C-2B

ULTIMATE AXIAL PILE CAPACITIES – OFFSHORE STRUCTURES

DRIVEN OPEN ENDED STEEL PIPE PILES ...................................................................................................................... PLATES C-3A AND C-3B DRIVEN SQUARE PRECAST CONCRETE PILES ............................................................................................................... PLATES C-4A AND C-4B BULKHEAD CONSTRUCTION - SHEET PILE WALL ............................................................................................................... PLATES C-5A AND C-5B SLOPE STABILITY ANALYSES ............................................................................................................................................... PLATES C-6A AND 6B

CLARK NEXSEN PSI REPORT 286-530

NEW INDUSTRIAL FACILITY & MOBILE BOAT HOIST STRUCTURES– USCG NOVEMBER 16, 2011

PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 1

PROJECT INFORMATION

Project Authorization

Professional Service Industries, Inc. (PSI) has completed a geotechnical exploration for the proposed Industrial Facility and Mobile Boat Hoist Structures (2 Finger Piers) to be constructed at the U.S. Coast Guard (USCG) Base located in Galveston, Texas. Mr. Gary Kiskinis, Principal of Clark Nexsen authorized our services on September 19, 2011 by signing PSI Proposal 286-51154 – Revision 1.0 dated August 24, 2011.

Project Description

Mr. Jeffrey Fisher, P.E., S.E. of Clark Nexsen provided the project information to PSI.

Based on the information provided, the proposed project includes construction of a new industrial facility and mobile boat hoist structures (2 finger piers) at the U.S. Coast Guard Base in Galveston, Texas.

It is understood that a new facility, H-G industrial will be constructed at the USCG Base in Galveston, Texas. The facility will be built to maintain and repair boats in the western Gulf of Mexico region. The proposed facility will be an addition to the existing SFO Galveston Engineering Building. The addition will be a pre-engineered steel frame construction and will be approximately 8,000 square feet in plan area. The new addition will include office and workshop space, including one work boat bay for maintaining and repairing boats up to 55 feet in length.

In addition, mobile boat hoist structures (2 finger piers) will be built offshore to remove non-trailerable boats from the water. The finger piers will be built to the south of the southernmost pier at the Base Galveston. The new piers will have concrete deck of approximately 110 feet long and 8 feet wide. It is understood that the dredging will be performed to accommodate the draft of the (87-foot) boats utilizing the finger piers. To lessen dredging requirements, a bulkhead of approximately 150 linear feet will be constructed from the southernmost existing pier to Base Galveston’s southern property line.

A laydown area is also planned immediately opposite to the pier structure. It is also understood that the existing parking lot near the SFO Galveston Engineering Building will be demolished and a new concrete pavement will be constructed.

Based on the topographic survey information provided to us, the grades within the existing parking lot range from EL. +10 feet to EL. +13 feet. The finish floor elevation of the proposed building addition (H-G Industrial) is set at EL. +14 feet.

The mudline elevation at the finger pier structures range from EL. -3 to EL. -10 feet. It is understood that dredging will be performed to EL. -10 feet. The top of the concrete deck of the proposed finger piers will be at EL. +10 feet.

PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 2

Based on information provided to us by Mr. Jeffrey Fisher, P.E. of Clark Nexsen, the top of the sheet pile wall will be at elevation +8 feet and will be capped on top with concrete. The top of the concrete cap will be at EL. +10 feet. The bottom of the channel will be dredged to an EL.-12 feet. The dredge depth includes over-dredge of about 2 feet for the sheet pile wall design. The water level on the retained side of the sheet pile wall is assumed to be at an EL. +0 feet.

The geotechnical recommendations presented in this report are based on the available project information, site location, laboratory testing, and the subsurface materials described in this report. If any of the noted information is incorrect, please inform PSI in writing so that we may amend the recommendations presented in this report if appropriate and if desired by the client. PSI will not be responsible for the implementation of its recommendations when it is not notified of changes in the project.

Purpose and Scope of Services

The purpose of this geotechnical study was to explore the subsurface conditions at the site to enable an evaluation of acceptable foundation and pavement designs for the proposed construction and the recommendations for the proposed sheet pile wall. The proposed geotechnical exploration for this project involved the collection of subsurface data, laboratory testing, and geotechnical analyses.

The proposed scope of field exploration included drilling a total of eight (8) soil borings at this site. In addition to soil borings, bulk soil samples were collected from four (4) different locations to perform laboratory Standard Proctor tests and California Bearing Ratio tests. The scope of exploration also included two (2) Double Ring Infiltrometer tests at the selected locations. This report briefly outlines the testing procedures, presents available project information, describes the site and subsurface conditions, and presents recommendations for the following:

Foundation types, depths, allowable bearing capacities, and an estimate of probable settlement for the proposed building addition.

Finger Pier foundation recommendations.

Bulkhead design recommendations.

Global slope stability analyses.

General pavement design criteria.

Comments regarding factors that will impact construction and performance of the proposed construction.

The scope of services did not include an environmental assessment for determining the presence or absence of wetlands, or hazardous or toxic materials in the soil, surface water, ground water, or air on or below, or around this site. Any statements in this report or on the boring logs regarding odors, colors, and unusual or suspicious items or conditions are strictly for informational purposes.

PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 3

A geologic fault study to evaluate the possibility of surface faulting at this site was beyond the scope of this investigation. Should you desire a detailed fault study, please contact us.

PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 4

SUBSURFACE CONDITIONS

Boring Locations and Subsurface Conditions

As discussed earlier, the subsurface conditions were explored by drilling a total of eight

(8) soil borings at this site.

Two (2) soil borings, B-1 and B-2 were performed offshore within the plan area of the proposed finger pier structures. These soil borings were drilled to a depth of about 80 feet below the mudline.

Two (2) soil borings, B-3 and B-4 were performed near shore along the proposed bulkhead location. The soils borings were drilled to a depth of about 80 feet below the existing ground surface. The borings were offset by 10 feet from the originally planned locations as the boring locations were not accessible to the truck mounted drill rig.

Two (2) soil borings, B-5 and B-6 were performed within the plan area of the proposed building addition. The soil borings were drilled to a depth of about 60 feet below the existing ground surface.

Borings B-7 and B-8 were performed in the pavement area and the laydown area. The borings were extended to a depth of 10 feet below the existing ground surface.

In addition, soil bulk samples were collected from 4 different locations to perform laboratory Standard Proctor tests and California Bearing Ratio tests.

Plate A-1A in Appendix A shows the approximate boring locations in plan. The boring locations were marked in the field by a PSI representative by measuring off from existing landmarks based on the information provided by the client. The on-shore borings were drilled using a truck mounted drill rig and continuous flight auger/wet rotary drilling methods. The off-shore borings were drilled using barge. Casing with wet rotary drilling method were utilized to drill the boreholes. Soil samples were routinely obtained during the drilling process. Drilling and sampling techniques were accomplished generally in accordance with ASTM procedures (ASTM D 1586 and D 1587).

The soil samples obtained during the field exploration were transported to the laboratory and selected soil samples were tested in the laboratory to determine the material properties for evaluation. Laboratory testing on selected samples included Moisture Content (ASTM D 2216), Unit Weight, Atterberg Limits (ASTM D 4318) Percent Passing No. 200 Sieve (ASTM D 1140), Unconfined Compression Strength tests (ASTM D 2166), Unconsolidated Undrained Triaxial tests (ASTM D 2850), Standard Proctor (ASTM D698), and California Bearing Ratio (CBR) tests (ASTM D 1883). In addition, two (2) Double Ring Infiltrometer tests (ASTM D 3385) were performed at the selected locations. Plate A-1B in Appendix A show the approximate CBR and Infiltrometer test locations in plan.

PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 5

The soil samples obtained from the drilling operation were classified in general accordance with ASTM D 2487 or D 2488. Laboratory test data along with detailed descriptions of the soils can be found on the logs of the borings. Plates A-2 through A-9 located in Appendix A show the logs of borings. A key to terms and symbols used on the logs is presented on Plate A-10 located in Appendix A. A generalized soil profile is included in Plate A-11 located in Appendix A.

The results of the Proctor tests and California Bearing Ratio (CBR) tests are presented in Plates B-1 through B-4 in Appendix B of this report. The results of the Double Ring Infiltrometer tests are presented in Plates B-5 and B-6 in Appendix B of this report.

Based on the soil borings, generalized soil profiles for the onshore and offshore construction have been identified and presented in the tables below.

Table 1A: Generalized Soil Profile: Soil Borings B-1 and B-2

(off-shore borings: waterfront & off-shore construction)

Stratum Elevation

Range

(feet) Description

I” --3 to -47 Clayey Sand with Silt (SC), Poorly Graded Sand (SP), Silty Sand (SM), Medium Dense to Very Dense

II -35 to -82 Fat Clay (CH), Lean Clay (CL), Sandy Lean Clay (CL), and Lean Clay with Sand (CL), Very Soft to Very Stiff

III -75 to -90 Fat Clay (CH), Stiff

* A stratum of Fat Clay with sand was encountered in Boring B-2 at EL. -16 to EL. -27 feet.

Table 1B: Summary of Soil Properties: Soil Borings B-1 and B-2 (off-shore borings: waterfront & off-shore construction)

Stratum Description

Moisture Content (%)

Atterberg Limits

Percent Passing

Minus 200 (%)

Shear Strength (tsf)

SPT - N

Values

I*: SC, SP, SM 24 to 94 - 4 to 74 - WOH to 50/3”

II: CL, CH 25 to 64 LL = 41 to 108 PI = 26 to 75

69 to 100 0.125 to 0.75 6 to 24

III: CH 42 to 49

LL = 56

PI = 34

-- 0.5 to 0.65 --

Note: LL = Liquid Limit; PI= Plasticity Index, NP = Non Plastic, WOH = Weight of Hammer;

* A stratum of Fat Clay with Sand was encountered in Boring B-2 at EL. -16 to EL. -27 feet.

PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 6

Table 2A: Generalized Soil Profile: Soil Borings B-3, B-4, B-5, B-6, B-7, and B-8 (on-shore borings: bulkhead, building addition and parking area)

Stratum Elevation

Range

(feet) Description

I +12 to +1 Fill: Clayey Sand, Lean Clay, Clayey Sand, Mixture of Sandy Clay, Silty Sand with shell fragments

II +4 to -38 Silty Sand (SM), Loose to Dense, Fat Clay and Sandy Lean Clay

III -37 to -70 Fat Clay (CH), Lean Clay (CL), and Sandy Lean Clay (CL), Soft to Stiff

Table 2B: Summary of Soil Properties: Soil Borings B-3, B-4, B-5, B-6, B-7, and B-8

(on-shore borings: bulkhead, building addition and parking area)

Stratum Description

Moisture Content (%)

Atterberg Limits

Percent Passing

Minus 200 (%)

Shear Strength (tsf)

SPT - N

Values

I: FILL 9 to 46 LL = 29 to 81 PI = 10 to 54

14 to 76 - 2 to 19

II: SM, CL,

CH,

23 to 61 LL = 60 to 72 PI = 40 to 49

6 to 93 0.1 to 0.5 WOH to 48

III: CH, CL 20 to 54 LL = 34 to 89 PI = 14 to 55

67 to 97 0.25 to 0.65 1 to 5

Note: LL = Liquid Limit; PI= Plasticity Index, NP = Non Plastic, WOH = Weight of Hammer;

The above subsurface description is of a generalized nature to highlight the major subsurface stratification features and material characteristics. The boring logs included in the Appendix should be reviewed for specific information at the boring locations. These records include soil descriptions, stratifications, locations of the samples, and laboratory test data. The stratifications shown on the boring logs represent the conditions only at the actual boring locations. Variations may occur and should be expected across the site. The stratifications represent the approximate boundary between subsurface materials and the actual transition may be gradual. Water level information obtained during field operations is also shown on the boring logs. The samples, which were not altered by laboratory testing, will be retained for 60 days from the date of this report and then will be discarded without any further notice.

PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 7

Double Ring Infiltrometer Tests

As requested, PSI performed 2 Double Ring Infiltrometer tests at the selected locations.

Plate A-1B in Appendix A shows the approximate test locations in plan. The locations were marked in the field by a PSI representative based on the information provided by the client.

The Double Ring Infiltrometer tests were performed in general accordance with ASTM D 3385. The results of the field tests are presented in Plates B-5 and B-6 located in Appendix B attached to this report.

Groundwater Information

Groundwater elevations at this site were measured at approximately at EL. +4 to 0 feet.

The on-shore borings were backfilled with soil cuttings after the drilling operations and were patched with non-shrinkable grout.

It is possible that seasonal variations (temperature, rainfall, tides etc) will cause fluctuations in the groundwater level. Additionally, perched water may be encountered in discontinuous zones within the overburden. The groundwater levels presented in this report are the levels that were measured at the time of our field activities. It is recommended that the contractor determine the actual groundwater levels at the site at the time of the construction activities to determine the impact, if any, on the construction procedures.

PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 8

FOUNDATION RECOMMENDATIONS

Geotechnical Discussion

The proposed project includes construction of a single story building addition as well as some waterfront work. The waterfront construction includes 2 finger pier (mobile boat hoist) structures and construction of the bulkhead. The project also includes demolition of the existing parking lot located near the SFO Galveston Engineering Building and construction of a new concrete pavement.

Based on the information obtained from the borings (B-5 and B-6) performed within the proposed building addition area, fill consisting of mixture of sandy clay, fat clay, and clayey sand was identified within the proposed addition area. The fill appears to be dredge materials extended to a depth of about 8 feet below the existing grade. The degree of compaction of the fill is unknown and could be varied. These materials are considered compressible and unsuitable for support of the structure. Structures directly supported on fill materials could undergo excessive and uneven settlement. As such, fill materials within the proposed building area should be removed in their entirety and replaced with compacted structural fill as recommended in this report.

It is understood that the proposed building addition will be supported on deep foundation system consisting of auger cast-in-place piles or precast square concrete piles. The recommendations for the pile capacities are provided in this report.

A slab-on-grade construction can be designed for the proposed building addition provided the existing fill materials are removed in their entirety and replaced with properly compacted structural fill. As an alternative to removing and replacing the existing fill between the slab and underlying soil, the floor slab settlement may be avoided by providing structural floor slab supported above the soil spanning between the piles.

PSI understands that the new addition will be constructed adjacent to the existing building.

It is understood that the existing building is supported on precast square concrete piles. It should be noted that the old foundations may have had undergone some settlement and that the new foundation will settle under the new loads resulting in a differential settlement between the old and the new foundations. The differential settlement between the old and the new foundation could be equal to or less than the total settlement of the new foundation. It should be noted that the constructability of the new addition should be assessed as the new foundation excavations could undermine the integrity of the old foundations.

The proposed finger piers (off-shore construction) can be supported on driven open ended steel pipe piles or driven square precast concrete piles. The recommendations for the requested size of the piles are provided in this report.

PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 9

The proposed project will also include installation of an anchored sheet pile wall along the shoreline to provide stability for the existing facility. The results of the anchored sheet pile wall analyses are provided later section in this report.

The foundation and pavement design recommendations along with the site preparation recommendations are presented in the subsequent sections of this report.

Site Preparation – New Building Addition

The following site preparation recommendations apply to the proposed building addition area. Subgrade preparation recommendations for the proposed pavement construction area are provided later in this report.

It is understood that the existing pavement within the proposed building addition area will be removed to accommodate the proposed construction. It is recommended that pavements, existing fill materials and other construction rubble, any topsoil, organic material within the construction area should be stripped from the site and wasted.

The fill material within the proposed addition area extended to as much as eight (8) feet (EL. +4 feet) should be over excavated and stockpiled separately for later use in the pavement area as the general fill materials. Any existing underground utility lines within the proposed construction area should be located and re-routed as necessary.

Depending upon the depth of the excavation, the bottom of the excavation may become unstable and difficult to compact due to the presence of the shallow water table. Localized dewatering by well point system may be required. The water table should be kept about 3 feet below the bottom of the excavation and be maintained until the structural fill is compacted in place.

After stripping and excavating to the desired grade as indicated above, the exposed soil should be proof-rolled to locate any soft or loose areas. Proof-rolling can be performed in accordance with Item 216 of Texas Department of Transportation, Standard specification for construction of highways, streets and bridges (TXDOT Spec). Soils that are observed to rut or deflect under the moving load should be undercut and replaced with properly compacted structural fill. The proof-rolling and undercutting activities should be witnessed by a PSI representative.

After proof-rolling and undercutting has been completed, any necessary fill placement may begin. The first layer of fill should be placed in a relatively uniform horizontal lift and be adequately keyed into the subgrade soils. Structural fill materials should be sandy lean clay or clayey sand/sand free of organic or other deleterious materials, have a maximum clay lump size of less than three inches, and have a liquid limit not greater than 35 and a plasticity index between 8 and 20. It is recommended that clayey sand/sand should be utilized as structural fill within the proposed building area to reduce the self weight

PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 10

settlement of the fill materials. Structural fill should be compacted to at least 98 percent of standard Proctor maximum dry density as determined by ASTM D 698.

Structural fill should be placed in maximum lifts of eight inches of loose material and should be compacted within the range of zero to three percentage (0% to +3%) points above the optimum moisture content value. If water must be added, it should be uniformly applied and thoroughly mixed into the soil by disking or scarifying. Each lift of structural fill should be tested by a representative of the geotechnical engineer prior to placement of subsequent lifts. Care should be taken to apply uniform compactive effort throughout the fill and fill scope areas. The moisture content and the degree of compaction of the structural fill soils should be maintained until the construction of structures within the area.

Pile Foundation Recommendations

It is understood that the proposed building addition as well as offshore structures (finger piers) are planned to be supported on a deep foundation system. As such, the following foundation design recommendations are provided for the proposed construction:

Proposed building addition (on-shore construction):

• Auger cast-in-place (ACIP) piles: 12 inch, 14 inch, and 18 inch diameter piles

• Driven square precast concrete piles: 12 inch, 14 inch, and 18 inch square piles

Proposed Mobile Boat Hoist Structures (Finger Piers -off-shore construction):

• Driven open ended steel pipe piles: 12 inch, 12.75 inch, 14 inch, and 18 inch diameter piles

• Driven square precast concrete piles: 12 inch, 14 inch, and 18 inch square piles

Please note that pile top elevation for the building addition will be at EL. +12 feet and the pile top elevation for the finger pier structures will be at EL. + 8 feet.

Design Criteria: The load carrying capacity of driven/ACIP piles can be computed using the static method of analysis. According to this method, the axial capacity, Q, at a given penetration is taken as the sum of the skin friction on the side of the pile, Qs, and the end or point bearing at the pile tip, Qp, so that:

Q = Qs + Qp = fAs + qAp

Where, As and Ap represent, respectively, the embedded surface area and the end area of the pile; f and q represent, respectively, the allowable unit skin friction and the allowable unit end or point bearing.

PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 11

The total axial capacity in compression will be the summation of the frictional capacity and the end bearing capacity. The total axial capacity in tension will be the frictional capacity alone neglecting the end-bearing component.

Axial Capacity: Using the static method of analyses and soil profiles determined, the ultimate axial capacities were computed. Plates C-1 through C-4 located in Appendix C shows the axial pile capacities for the pile sections presented above. The curves on the plates show the ultimate axial pile capacities (in compression and tension) in kips versus elevation in feet. It is recommended that a factor of safety of at least 2.0 be applied to arrive at allowable values.

It should be noted that depending on the proximity of the new structure (in the building area) to the existing structures, the existing structure may get affected due to vibrations and soil heave during pile driving. In driving piles, it is recommended that the piles closest the structure should be driven first continuing with the piles moving away from the structure. Vibration monitoring may be performed during the installation of the piles.

The pile capacities in the batter direction are similar to the pile capacities in vertical direction for a pile driven to that particular elevation. In other words, the piles would have an axial capacity corresponding to that elevation regardless of the angle at which it is installed. The elevation should not be confused for the length of the pile. The length of the pile will depend on the required tip elevation for capacity and the batter angle.

Lateral Capacity: The soil as well as the rigidity of the pile resists the lateral loads on the pile. Once the locations, loads and other pertinent information are provided, PSI can assist in performing a lateral load analyses based on methods ranging from chart solutions to the ‘p-y’ approach utilizing computer programs such as LPILE or COM 624.

The lateral design information regarding the 'p-y' data for the piles supporting the finger piers is provided in Table 3. The relationship between the soil resistance (p) and pile deflection (y) is commonly referred to as 'p-y'. Along the depth of the pile, soil resistance

(p) is expressed as a non-linear function of lateral pile deflection (y). Various researchers developed 'p-y' criteria for different kinds of soils. The 'p-y' curves can be automatically generated utilizing the computer program LPILE. The program LPILE was developed by Lymon Reese and Shin-Tower Wang, Ensoft, Inc. ‘p-y’ parameters for LPILE analyses are provided for the analyses of individual piles.

PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 12

Table 3: Soil Parameters to be used in the Lateral Load Analyses (off-shore structures; Borings B-1 and B-2)

Stratum Elev.,

(ft) ‘p-y’ Criteria

Effective Unit

Weight, (pcf)

Su (ksf) , or Ф degrees

Ks (pci) or Kc (pci) 50

I: SP/SC -10 to -15 Neglect 60 -- -- -

II: SC -15 to -45 Submerged

Sand Criteria 60 Ф= 250

Ks or Kc = 60 pci

III: CL,CH -45 to -67 Soft Clay Criteria

60 Su = 0.6 Ks = 100 pci

0.01

IV: CH -67 to -90 Stiff Clay Criteria

55 Su = 1.2 Ks = 500 pci Kc = 200 pci

0.007

Note: Su-Undrained Shear Strength (ksf); Ф, Angle of Internal friction; Ks-modulus of subgrade reaction (pci) for static loading condition; Kc-modulus of subgrade reaction (pci) for cyclic loading condition; 50 – strain corresponding to one-half the principle stress.

Neglect the upper 5 feet of the soils for the lateral load analysis

Settlement: A detailed analysis of axial load versus settlement was beyond the scope of this study. However, for a single isolated pile designed in accordance with the computed ultimate capacities and recommended factor of safety, the settlement should be less than ½ inch. A detailed settlement analysis for piles was beyond the scope of this study. If desired, PSI can assist in performing such a study.

Group Action: A group of piles subjected to vertical loads may not necessarily have the same capacity as the sum of the capacities of the individual piles. For axially loaded piles, published results indicate that the ratio of capacity per pile in a group to that of a single isolated pile typically ranges from 0.5 to 1.0. This efficiency factor depends on the spacing or distance between each pile. In planning groups of piles, a minimum center-to-center spacing of 3D (where D is the diameter or the width) is recommended to avoid the reduction in capacity. Group action should be checked after the actual pile spacing is determined. Further, if the pile spacing is designed to be closer, construction sequence and other installation issues must be addressed.

A group of piles subjected to lateral loads may not have the same capacity as the sum of the capacity of the individual piles. For laterally loaded piles, published results indicate that the ratio of capacity per pile in a group to that of a single isolated pile typically ranges

PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 13

from 0.5 to 1.0. This efficiency factor depends on the pile spacing (distance between each pile) and on the direction of loading with respect to the orientation of the pile group.

Research indicates a minimum spacing of 3 diameters to 6 diameters is required depending on the direction of loading with respect to the orientation of the piles in a group.

PSI should be contacted, once the pile group orientation, spacing and loading direction is determined.

Driven Pile Installation: Piles can be driven in accordance with Item 404, Texas Department of Transportation, Standard specification for construction of Highways, Streets and Bridges (TxDOT Specification). Prestressed Concrete Piling can be in accordance with Item 409 of TxDOT Specification and Steel Piling can be in accordance with Item 407 of TxDOT Specification

The piles should be driven to the desired penetration depth by driving methods alone. Any supplemental techniques such as use of vibratory hammers, pilot holes or jetting should be avoided whenever possible. These supplemental techniques, if not used properly, can reduce the pile capacity. If the use of pilot holes or jetting becomes necessary, PSI should be contacted to provide further recommendations.

Driving should be performed such that the hammer speeds are adjusted appropriately and that the piles are not over-stressed and crack.

We recommend that the pile driving be monitored by a geotechnical engineer or qualified technician. Sometimes, premature refusal occurs due to poor hammer performance rather than from soil resistance. Any changes in hammer blow counts should be carefully examined before making any decisions about the pile penetration.

Piles could heave during the driving process as a result of being driven adjacent to one another. We suggest that if piles heave more than about 0.25 inch during the driving of an adjacent pile, the heaved piles should be re-driven to their initial depth. The ground surface surrounding the piles could also heave as a result of driving these displacement piles. When driving piles near existing structures, it is recommended that the driving sequence start with the piles nearest the existing structures and progress in a direction away from the structures.

It should be realized the pile capacity is dependent on the prevention of damage to the pile during construction. A damaged pile will have reduced performance under sustained loading conditions. Proper pile handling and proper driving govern the pile construction during construction. In addition, pile material strength, especially for precast piles can also dictate pile capacity. Good pile driving practice should be adopted to ensure proper driving. Among other things, proper driving includes the use of a proper pile cushion, reducing or increasing the hammer speed anticipating soft or hard driving situations. A proper pile driving record should be utilized to ensure proper pile driving. In maintaining pile driving records, among other things the primary things include, recording the blow

PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 14

counts for every foot of pile penetration, and, and recording actual time (excluding stoppage) that was required to drive the pile.

Pile Hammer Selection: Selection of an appropriate hammer depends on several factors such as hammer performance, cushion type and size, pile type, pile size and length, pile weight, predicted or required pile capacity, soil resistance, etc.

The selected hammer must be able to drive the pile to the required capacity or length without damaging the pile. Generally, experience of local contractor is often the primary source for the selection of the hammer. Wave equation analysis of piles may be used to aid in hammer selection. It can be used to predict the pile capacity, driving resistance and stresses in the pile during driving. In the field, dynamic testing using a Pile Dynamic Analyzer (PDA) can be used on the test piles to select a proper hammer, predict driving resistance, and evaluate the stresses in the piles. Once the design is finalized, PSI can be contacted to perform further analysis and assist hammer selection.

Auger Cast-In-Place Pile Installation: ACIP piles can be installed in accordance with ACIP Pile Manual (DFI 1990)1. The successful completion of ACIP pile installations will depend to a large extent on the suitability of the equipment and the installation procedures used. The rate of drilling and auger withdrawal should be at a steady and constant rate to prevent necking of the pile. A sufficient head of grout should be maintained in the auger system at all times during grouting. A quantity of grout equivalent to five feet of pile volume or more should be pumped prior to initiating the auger withdrawal. The volume of concrete grout placed per every 5-foot length of the pile should not be less than 1.15 times the calculated volume for every 5-foot length of pile. The total volume of concrete grout placed should be approximately 1.3 times the theoretical volume of the design pile dimensions.

PSI should be retained to review and comment on specifications developed for auger cast pile foundation installation. We recommend that no two adjacent piles that are located within four-pile diameters to each other be installed on the same day.

Non-shrink grout should be fluid, with appropriate design mix and additives and should be placed at appropriate temperature and age. Fluidity of the grout should be checked frequently during installation using a ¾-inch flow cone in accordance with ASTM C 939.

Flow rates of 15 to 25 seconds are typically considered acceptable when using ¾-inch flow cone. Compressive strength of the grout mix should be verified and the sampling and testing should be performed ASTM C 109.

A geotechnical engineer should observe and monitor installation of piles. Proper installation of the ACIP piles is critical to achieving a successful foundation. The pile installation monitoring should include:

1 Deep Foundation Institute, Committee on Auger Cast-In-Place Piles, Auger Cast-In-Place Piles Manual, 1990.

PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 15

Inspection of the pile installation equipment and reporting non-conformance to specifications.

Calibration of grout pump in units of volume per pump stroke. It is recommended that grout pump be calibrated prior to the start of the project, immediately after any significant maintenance/repair and/or any time the inspector suspects that the pump is operating differently from the last calibration. It is recommended that the grout pump calibration include recording the number of full pump strokes required to fill a container of at least 55-gallons.

Monitoring and recording; 1) the amount of grout pumped for every single pile installed, 2) the volume of grout pumped per unit length of pile to determine the finished shape of the pile, and 3) the rate and pressure at which the grout is pumped.

Monitor and record the rate of drilling, auger withdrawal with respect to maintaining required grout pressure.

Grout sampling and testing.

PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 16

Floor Slab Recommendations

A slab-on-grade floor slab can be constructed provided the site is prepared in accordance with the recommendations mentioned in the site preparation section of this report.

The structural fill should be placed within the plan area of the structure and to a distance of at least five feet beyond the perimeter of the structure. It is understood that about 8 feet of fill will be placed under the floor slab.

Clayey sand/sand should be utilized as structural fill to reduce the self weight settlement of the fill materials. Structural fill should be compacted to at least 98 percent of standard Proctor maximum dry density as determined by ASTM D 698.

For a structural fill thickness of 8 feet below the floor slab, a total estimated settlement of about 1 inch should be expected under the floor slab. If, due to grading requirements, the structural fill thickness under the slab is planned to be more than 8 feet, PSI should be contacted as this may change the estimated settlement values.

As an alternative to providing structural fill between the slab and underlying soil, the effects of fill settlement on the floor slab may be avoided by providing structural floor slab supported above the soil spanning between the piles.

PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 17

BULKHEAD RECOMMENDATIONS

The proposed project includes the installation of an anchored sheet pile wall along the shore-line of the USCG facility. The bulkhead of approximately 150 linear feet will be constructed from the southernmost existing pier to Base Galveston’s southern property line. This bulkhead will provide additional storage area for piles and space for mobile boat hoist maneuvering. It is understood that the existing rip-rap (concrete blocks) will be removed and an anchored sheet pile wall will be installed to provide the stability to the existing facility.

Sheet Pile Wall Analyses

Anchored sheet piles derive their support to resist the lateral earth pressures by two means: passive pressures on the embedded portion of the sheet pile and anchor forces near the top of the piling. A computer program "CWALSHT" was used to perform the analyses of anchored sheet pile walls. The program is developed by Information Technology Laboratory, Department of Army, Waterways Experiment Base, Corps of Engineers, Vicksburg, Mississippi.

The program utilizes classical soil mechanics procedures to determine the minimum wall penetration depths, moment and shear along the length of the pile. Classical soil mechanics procedures include determining the earth pressure coefficients (both active and passive) based on Coulomb/Rankine theory. The analyses were performed based upon the ultimate earth pressure values; i.e., with a factor of safety 1.0 and utilizing Fixed Earth Support Method (for anchored walls).

The sheet pile wall analyses for anchored conditions for the proposed bulkhead along the shore line were performed using the following design assumptions.

Top of Sheet Pile Wall: EL. +10 feet (with concrete cap) Anchor Elevation (for anchored wall): EL. +6 feet Water Elevation: EL + 0 feet (on both sides) Dredge Elevation: EL. -12 feet (sloping down at 1V:6H) Surcharge Load: Uniformly Distributed Load: 250 psf

The material properties were selected based on soil borings which exhibited general similarities. The strength parameters for short term and long term conditions were selected from the subsurface conditions encountered in the borings. The soil properties used in our analyses are summarized in Table 4.

PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 18

Table 4: Soil Parameter for the Proposed Bulkhead Along Shoreline (B-3 & B-4) Soil Type Elevation

(Feet) Total Unit

Weight (pcf)

Short Term Long Term Cohesion

(psf) Angle of Friction

(Degrees)

Cohesion (psf)

Angle of Friction

(Degrees) Sand

(Backfill) +10 to +2 120 0 25 0 25

Sand + 2 to - 17 120 0 25 0 25 Sand - 17 to - 37 120 0 30 0 30 Clay -37 to - 70 115 800 0 0 22

The analyses for proposed sheet pile wall were performed using both the short term and long term soil parameters. Identical results were obtained for the short term and long term conditions and are recommended herein. The recommended results are included in Plate C-5A in Appendix C. The analyses included the determination of 1) minimum penetration required; 2) shear force along the length of the wall; 3) maximum moment along the length of the wall; and, 4) anchor force. The results are summarized in Table 5.

Table 5: Results of Analyses for the Proposed Bulkhead Along Shoreline

Analyses Condition

Embedment Length (feet) and

Minimum Tip Elevation

Maximum Bending Moment (kip-ft.)

Anchor Force (kips per lineal feet)

Anchored

23.4 feet and El -

35.4 feet

56.5 8.4

Notes:

The results shown correspond to a factor of safety of 1.0. Therefore, it is recommended to increase the embedment length of the sheet pile by 30 percent. The structural engineer in determining the final sectional modulus of the sheet pile should assume an adequate factor of safety. A factor of safety of 2.0 should be used on the anchor force to design the anchorage system.

The overall stability of the sheet pile system depends on the flexural rigidity of the sheet pile, stability of anchorage system, adequate embedment depth of the sheet pile, and global slope stability. It is common to increase the embedment length of the sheet pile by 30 percent. A factor of safety of 2.0 should be used on the anchor force and adequate factor of safety should be adopted in determining the final length and section modulus of the anchorage sheet wall.

PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 19

Anchorage System

It is understood that driven sheet piles will be used as an anchor (anchor wall) for the new sheet pile wall. Passive pressure values and the minimum distance for placement of the anchor wall are shown on Plate C-5B in Appendix C. The values shown on the sketch do not include any factor of safety and are ultimate resistance values.

A factor of safety of 2 should be used on the anchor force and an adequate factor of safety should be adopted in determining the final length and section modulus of the anchorage sheet pile wall. Based on the recommended factor of safety, the anchor force should be multiplied by two for determining the spacing and the size of the tie rods, and, the length of the anchor sheet wall.

For “A-Frame” type anchorage system, the 'p-y' lateral design data is provided in Table 6.

For evaluation of the lateral capacity of the soil-structure, the top 8 feet of fill soil should be neglected.

Table 6: Soil Parameters to be used in the Lateral Load Analyses

Elev., (ft)

‘p-y’ Criteria

Effective Unit Weight, (pcf)

Su (ksf) , or Ф degrees

Ks (pci) or Kc (pci) 50

+10 to +2 Neglect 120 -- -- -

+2 to -17 Submerged

Sand Criteria

60 Ф= 250 Ks or Kc = 60 pci

-17 to -37 Submerged

Sand Criteria

60 Ф= 300 Ks or Kc = 60 pci

-37 to -70 Soft Clay Criteria

55 Su = 0.8 Ks = 100 pci

0.01

PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 20

Global Stability Analyses

Generally, slope failure occurs when the weight of the sliding soil exceeds the resistance derived from the shear strength or frictional resistance of the soil along the sliding surface.

Slope stability analysis involves the determination of the most likely sliding surface by comparing the developed shearing resistance along a sliding surface with the weight forces associated with the sliding soil. The method of comparison involves the determination of the factor of safety i.e., a ratio of shear resistance along a sliding surface to the weight of the sliding soil. Slope stability analysis is a method to check the stability of the soil slope. The check for stability involves determination of various values factor of safety along various assumed likely sliding surfaces. The least value of factor of safety corresponding to a sliding surface is considered the stability of the slope. For the slope stability analysis, the failing surfaces are typically assumed to be circular.

For the present study, to predict the factor of safety against sliding, a computer program Slope/W was utilized. The analysis included the determination of a particular sliding surface that has a least factor of safety against sliding. For the slope stability analyses, 2 different analysis conditions were considered. They are:

Short term or Undrained Condition: This condition occurs when the pore pressures within the soil mass are not dissipated. Typically, this condition corresponds to the state of the soils that exist immediately after performing any cut/fill or during the construction. For this condition, the slope stability analysis is performed using undrained soil parameters obtained from laboratory tests such as unconfined compression tests and unconsolidated-undrained tests.

Long term or Drained Condition: This condition occurs when the pore pressures within the soil mass are dissipated. Typically, this condition corresponds to the state of the soils a few months or years after the construction is complete. For this condition, slope stability analysis is performed using drained or effective stress parameters obtained from consolidated-drained tests such as direct shear tests or consolidated-undrained tests with pore pressure measurements. These laboratory tests were not performed for this project and therefore correlations with Atterberg limits were utilized to obtain these test parameters.

The soil strength parameters selected for the slope stability calculations are based on: 1) the results of field and laboratory test data, 2) engineering judgment based on experience with similar soils and 3) published correlations. The soil strength parameters used in the stability analysis for various soil layers are presented in Table 4.

Using the parameters selected the slope stability analyses were performed. For the present study, surcharge pressure of 250 is considered in the analyses. The results of the analyses are presented on Plates C-6A and C-6B in Appendix C.

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Based on the slope stability analyses results, for an anchored sheet pile with a tip elevation of -40 feet (includes 30% increase in embedment length), the factors of safety obtained for the short term and long term conditions are greater than 1.5 indicating adequate and stable conditions in the short term and long term conditions.

PROFESSIONAL SERVICE INDUSTRIES, INC. PAGE 22

PAVEMENT RECOMMENDATIONS

In order to design a pavement, the subgrade soil conditions and anticipated levels of traffic must be known. The subgrade soils are evaluated based on our limited testing.

The anticipated traffic on the proposed pavement is not known at this time. Based on our previous experience with similar facilities, the traffic for the proposed pavement could include lightly loaded cars/pick trucks, delivery vans or trucks, and dump trucks.

The general pavement design information presented in this report is based on information published by AASHTO and the Portland Cement Association as well as past experience in this area. The published information was utilized in conjunction with the available field and laboratory test data to develop general pavement recommendations.

For the pavement design purposes, we have estimated a CBR value of 2.5 for the existing soils/imported fill and a Coefficient of Subgrade reaction (k) of 100 psi per…