25-037A Reference Documents.pdf

Reference Documents

Harbor Point

The Reference Drawings and Geotechnical Reports are being provided separately as reference documents for reference use only and are not part of the Construction Contract. The Contractor is responsible for verification of information referenced in the document for reference.

SUPPORTING DOCUMENTATION

for

Harbor Point

PCCA Project No. 25-037A

1. Geotechnical Report, UES #A26181.00019, dated March 30, 2026.

2. Geotechnical Report, Rock Engineering #G122122, dated May 20, 2022.

3. Geotechnical Report (Supplement No. 01), Rock Engineering # G122122, dated June 21, 2022.

4. Harbor Bridge Groundwater Investigation Report, Global Environmental Assessments & Response

(GEAR), dated March 17, 2026, performance date March 05, 2026.

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O nly

01.

Geotechnical Report

UES #A26181.00019

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GEOTECHNICAL ENGINEERING REPORT

Harbor Point West Harbor Drive

Corpus Christi, Texas 78401 UES Project No. A26181.00019

March 30, 2026

Prepared for:

Richter Architects 201 South Upper Broadway Corpus Christi, Texas 78401

Attention: Ms. Elizabeth Chu Richter, FAIA, Hon. FRAIC

Prepared by:

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UES

11818 W Business Hwy 83, Unit 1

La Feria, Texas, 78559

956.201.4797 | TeamUES.com

Environmental Consulting | Geotechnical Engineering | Materials Testing & Inspections Occupational Health & Safety | Building Sciences & Code Compliance | Virtual Design Consulting

March 30, 2026

Richter Architects 201 South Upper Broadway Corpus Christi, Texas 78401

Attention: Ms. Elizabeth Chu Richter, FAIA, Hon. FRAIC

Re: Geotechnical Engineering Report Harbor Point West Harbor Drive Corpus Christi, Texas 78401 UES Report No. A26181.00019

UES has performed a geotechnical exploration for the project referenced above. This study was authorized by Ms. Elizabeth Chu Richter, FAIA, Hon. FRAIC with Richter Architects and performed in accordance with UES Proposal No. CGP052725A dated December 23, 2025.

The results of this exploration, together with our recommendations, are presented in the accompanying report, an electronic copy of which is being transmitted herewith.

UES appreciates the opportunity to be of service on this project. If we can be of further assistance, such as providing materials testing services during construction, please contact our office.

Sincerely, Sukanta Chakraborty, P.E. Neve Steger, M.S., E.I.T.

Senior Geotechnical Engineer Staff Engineer

UES

TBPELS Firm No. 2For

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1.0 INTRODUCTION

2.0 SITE CONDITIONS

3.0 FIELD EXPLORATION

4.0 SUBSURFACE CONDITIONS

4.1 Geology

4.2 Subsurface Lithology

4.3 Groundwater Observations

4.4 Seismic Site Classification

5.0 LABORATORY TESTING

6.0 RECOMMENDATIONS

6.1 Existing Fill, Soft Soils and Demolition

6.1.1 Existing Fill

6.1.2 Demolition

6.2 Potential Movement of Expansive Soil

6.2.1 Expansive Soil Mitigation

6.3 Settlement Estimates of Earthen Mound

6.4 Earthwork

6.4.1 Excavation Safety Considerations

6.4.2 Site Preparation and Proofroll

6.4.3 Construction Considerations

6.4.4 Grading, Drainage and Other Considerations

6.4.5 Groundwater Control

6.4.6 Fill Compaction

6.4.7 Utilities

6.5 Stacked Block Wall and Shade Structure Foundation Systems

6.5.1 Shallow Footings on Aggregate Piers for the Stacked Block Wall

6.5.2 Shallow Footings for Shade Structures

6.5.3 Drilled Shafts

6.6 Pavement

6.6.1 Pavement Subgrade

6.6.2 Rigid Pavements

6.6.3 Flexible Pavements

7.0 LIMITATIONS/GENERAL COMMENTS

Appendix A. Site Vicinity Map and Boring Location Plan Appendix B. Boring Logs Appendix C. Key to Soils Appendix D. CPT Logs

TABLE OF CONTENTS

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Geotechnical Engineering Report UES Project No. A26181.00019

Harbor Point West March 30, 2026

1.0 INTRODUCTION

Purpose and Scope. The purpose of this geotechnical study was to evaluate some of the physical and engineering properties of subsurface materials at selected locations on the subject site in order to develop geotechnical engineering design parameters and recommendations for the proposed project. To accomplish this, the scope of this study included: a field exploration, consisting of drilling test borings, collecting samples of the subsurface materials; performing Cone Penetration Test soundings (CPT); performing laboratory testing on selected samples obtained during the field exploration; evaluating the subsurface conditions with respect to the project characteristics; and developing geotechnical recommendations suitable for the proposed project. The scope of services did not include an environmental assessment of the site. Any statements in this report, or on the boring logs, regarding odors, colors, unusual or suspicious items or conditions are strictly for the information of the client.

Limitations. Recommendations provided in this report were developed from information obtained in the test borings and CPT soundings depicting subsurface conditions only at these specific locations and at the particular time designated on the boring or CPT Sounding logs. Subsurface conditions at other locations may differ from those observed at the boring or CPT sounding locations, and subsurface conditions at the boring and CPT sounding locations may vary at different times of the year. The scope of work may not fully define the variability of subsurface materials and conditions that are present on the site. The nature and extent of variations between borings and CPT soundings may not become evident until construction. If significant variations then appear evident, our office should be contacted to re-evaluate our recommendations.

Project Location. The project is located in underneath the old Harbor Bridge at Harbor Drive in Corpus Christi, Texas 78401. The general location of the site is shown on the Site Vicinity Map provided in Appendix A.

Project Description. Based on information provided to UES, the project will include construction of a new earthen mound amphitheater with terraced concrete seating. The crescent shaped earthen mound amphitheater will be about 200 feet in length and 8 feet in maximum height. A stacked block retaining wall is planned at the mound’s north end while a slope with an inclination of around 4H:1V is planned at the southeast end of the earthen mound. Interconnected bio-infiltration detention basins are planned throughout the southern portion of the site as are concrete flatwork walking paths. We understand that materials excavated from the bio-infiltration detention basins are planned to be used as fill for the earthen mound structure. The area will also feature a paved food truck area with shade structures and several green spaces.

Loading Information. Structure loading information was not available at the time of this report. However, we anticipate that foundations supporting shade structures and other ancillary structures requiring foundations will have maximum foundation loads of 10 kips or less. At the location of the stacked block wall we anticipate that the ground pressure will be on the order of 1,200 psf based on a wall height of 8 feet. Any change in the

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Harbor Point West March 30, 2026 structural loads should be brought to our attention to review and assess the suitability of the recommendations provided.

Site Grading. Based on topo elevations obtained from Google EarthTM, the site features existing elevations on the order of El. 5 to El. 6 on the east side and El. 10 to El. 11 along the west side. Existing elevations across the earthen mound amphitheater appear to range from El. 10 to El. 11 while the existing elevations across the bio-infiltration detention basins range from El. 9 to El. 11. As indicated on the conceptual site plan provided by the client, the earthen mound amphitheater will feature a crest elevation of around El. 18, requiring about 8 feet of fill. The bio-infiltration detention basins feature bottom elevations ranging from El. 2.5 to El. 4.5 on the east side to El. 4 and El. 6 in the center and west sides, thus resulting in cuts on the order of 4 to 6½ feet. Additionally, the perimeter walking paths will feature cuts and fills on the west side of less than 1 foot to reach finish grades while about 2 to 3 feet of fill appears to be required along the east side of the site.

When final site grading plans become available, UES should be notified and allowed to review the site grading plan to assess and modify our recommendations, as necessary.

2.0 SITE CONDITIONS

Site Observations. During the field exploration the site was observed to be under ongoing demolition and construction. Existing pavement was present at the site and located centrally, where the amphitheater is to be constructed. At the time of our field investigation the condition of the ground surface was firm and did not pose significant difficulties to the drill rig accessing the boring locations.

Review of Aerial Images. Review of aerial images available from Google Earth™ indicate the site has been utilized as a paved area for vehicle traffic and parking as early as 1985.

It is also understood that the adjacent waterway has been expanded over the previous 75 years through canal dredging, with dredged material deposited in the general area of the site. Due to the intermittent nature and relatively low resolution of aerial photographs, as well as lack of provided information regarding the past land use of the site, our review should not be interpreted as eliminating the possibility of past activities on site which could detrimentally affect future construction. No additional information was provided for this study regarding previous site activities or development.

3.0 FIELD EXPLORATION

Test Borings. The field exploration for this project included performing a total of five (5) borings and two (2) CPT test borings at the locations as summarized in the following table. It should be noted that due to site access restrictions, the boring scope was completed over two mobilizations; D-1 and CPT-1 were performed on 01/22/26 and the remaining borings and CPT-2 were performed on 03/04/26. Boring depths were measured from the existing ground surface at the respective boring location at time of the field exploration.

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Summary of Boring Depths and Locations

Boring Identification

Depth, feet Location

B-101/CPT 1 60

Earthen Mound Amphitheater

B-102/CPT 2 60

D-1 20 Bio-Infiltration Detention Basin and Paving Area

D-2 and D-3 10 Bio-Infiltration Detention Basin Area

Test borings were advanced using a drilling rig equipped with a rotary head using hollow stem augers. UES located the borings in the field using a hand-held GPS unit with a lateral accuracy of ± 20 feet; therefore, the boring locations should be considered approximate. The boring locations were not surveyed.

Disturbed Soil Sampling. Disturbed soil samples were obtained using split-barrel sampling procedures in general accordance with the procedures for “Penetration Test and Split-Barrel Sampling of Soils, (ASTM D1586)”. During the sampling procedures, SPTs were performed to obtain the standard penetration value of the soil at a selected intervals with a standard 2-inch outside diameter (OD) split barrel sampling spoon driven 18 inches into the ground using a 140-pound (lb) hammer falling 30 inches. The number of blows for the last 12 inches of a standard 18-inch penetration is recorded as the Standard Penetration Test resistance (N-value). The N-values are recorded on the boring logs at the depth of sampling. Samples were sealed and returned to the laboratory for further evaluation and possible testing.

Cone Penetration Test Soundings (CPT). The CPT is an in-situ test method used to determine the geotechnical engineering properties of soils and delineating soil stratigraphy. It was initially developed in the 1950s at the Dutch Laboratory for Soil Mechanics to investigate soft soils. Based on this history it has also been called the “Dutch cone test”. Today, the CPT is one of the most used and accepted soil methods for soil investigation worldwide. The test method consists of pushing an instrumented cone, with the tip facing down, into the ground at a controlled rate. The resolution of the CPT in delineating stratigraphic layers is related to the size of the cone tip, with typical cone tips having a cross-sectional area of either 10 or 15 cm², corresponding to diameters of 3.6 and 4.4 cm. The data obtained from the CPTs are provided on the attached sounding logs and includes sounding locations, sounding depths, estimated soil classifications and soil strengths.

Groundwater Observations. A summary of groundwater observations is provided in Section 4.3.

Borehole Backfilling and Plugging. Upon completion of the borings, the boreholes were backfilled with on-site soil cuttings and concrete and/or asphalt patched as necessary.

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4.0 SUBSURFACE CONDITIONS

4.1 Geology

Geologic Formation. Based on the 1975 Geologic Atlas of Texas, Corpus Christi Sheet, the project site appears to be located within the Fill and Spoil (F S) formation. The F S formation generally consists of fill and spoil, or material dredged for raising land surfaces above adjacent alluvium and barrier island deposits and for creating land. The F S formation is highly variable, consisting of mixed mud, silt, sand, and shell.

4.2 Subsurface Lithology

Stratigraphy. Descriptions of the various strata encountered in the borings and CPT soundings and their approximate depths and thickness are provided on the boring logs in Appendix B and CPT logs in Appendix D. Terms and symbols used in the USCS are presented on the Key to Soils provided in Appendix C. Depths referenced in this report are measured from the existing ground surface at the respective boring location at time of the field exploration. It should be noted that the depths provided in the tables and on the boring logs are based on our Field Technician’s and Engineer’s interpretation of conditions believed to exist between actual samples retrieved. Therefore, information on the boring logs contains both factual and interpretive information. Lines delineating subsurface strata are approximate and the actual transition between strata may be gradual or not clearly defined. In addition, variations may occur between or beyond the boring locations.

The generalized soil conditions encountered at the project site have been summarized and soil properties including soil classification, strength, and plasticity are provided in the following tables.

Soil Profile 1: Earthen Mound Amphitheater (Borings B-101 and B-102)

Depth Description LL PI -#200 C γe N

0-6 Possible FILL: Clayey

SAND

21-31 8-17 35-50 -- 28 115 2-7

6-11.5 Sandy Lean CLAY and

Fat CLAY 38 24 59 300 -- 115 1-4

11.5-14.5 Clayey SAND, Silty SAND and Poorly

Graded Sand with Silt

NP NP 10 -- 28 55 1-8

14.5-16.5 Sandy Lean CLAY and

Silty CLAYEY Sand -- -- -- 500 -- 55 2

16.5-18.5 Silty SAND and Silty

Clayey SAND -- -- -- -- 28 55 --

18.5-22 Silty CLAYEY Sand 23-24 8 14-24 500 -- 55 1

22-34 Fat CLAY, Lean CLAY and Lean CLAY with

Sand 52 30 88 500 -- 55 1

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34-48

Fat CLAY, Lean CLAY with Sand, Sandy Lean

CLAY and CLAYEY Sand

43-59 25-39 79-88 700 -- 55 1-2

48-52 Sandy Lean CLAY and

CLAYEY Sand 32 17 50 1,000 -- 55 5-7

52-57 Poorly Graded SAND with SILT and SILTY

SAND

NP NP 13 -- 30 55 5-8

57-60 Poorly Graded SAND with SILT and SILTY

SAND

NP NP 7 -- 34 55 22-24

Soil Profile 2: Bio-Infiltration Detention Areas (Boring D-1)

Depth Description LL PI -#200 N

0-3 Possible FILL: Fat CLAY with Sand and

CLAYEY Sand 54-56 38-40 73-75 4-6

3-13 Possible FILL: Poorly Graded SAND, Poorly Graded SAND with SILT and Clayey SAND

NP NP 11 2-3

13-20 CLAYEY Sand 24 8 45 2

Soil Profile 3: Bio-Infiltration Detention Areas (Boring D-2)

Depth Description LL PI -#200 N

0-9 Possible FILL: CLAYEY Sand 25-38 11-25 15-44 4-7

9-10 Sandy Lean CLAY -- -- -- 2

Soil Profile 4: Bio-Infiltration Detention Areas (Boring D-3)

Depth Description LL PI -#200 N

0-3 Possible FILL: Fat CLAY with Sand 54-56 38-40 73-75 4-6

3-4.5 Possible FILL: Silty SAND -- -- -- 3

4.5-10 Sandy Lean CLAY and Fat CLAY with Sand 48 35 45 1-2

Where:

D = Depth in feet below existing grade LL = Liquid limit (%) PI = Plasticity index C = Soil Cohesion, psf (undrained)

= Angle of Internal Friction, deg. (undrained) γe = Effective soil unit weight, pcf -#200 = Material passing #200 sieve, % N = SPT N-value range, bpf

Exceptions to the above generalized soil table do exist. Detailed descriptions of the soils encountered at the boring locations are provided on the boring logs included in the Appendix.

Surficial Materials And Existing Fill. Existing pavement materials were observed in the central portion of the site underneath the old Harbor Bridge. Existing fill generally consisting of clayey sand was encountered to various depths in all borings. Based on the

For Refe ren ce results of the field testing the existing fill appears to have been placed with some level of compactive effort. However, documentation in regards to the placement and compaction of the existing fill was not available at the time of this report.

4.3 Groundwater Observations

Groundwater Levels. Groundwater levels encountered in the borings, and the depths the borings caved, during this study are identified in the table below. Depths referenced in this report and in the following table are measured from the existing ground surface at the respective boring location at time of the field exploration.

Summary of Groundwater (GW) Level Observations

Boring No. During Drilling (feet) Delayed Readings (hour : feet) Caved Depth (feet)

B-101 18 24 : 12.5 18

B-102 6.5 24 : 13 17

D-1 6 Not Observed 5.5

D-2 8.5 Not Observed Not Observed

D-3 6 Not Observed Not Observed

Note: Borings B-101 and B-102 were terminated at a depth of 60 feet. Borings D-2 and D-3 were terminated at a depth of 10 feet, and Boring D-1 was terminated at a depth of 20 feet.

Long-term Groundwater Monitoring. Groundwater observations in this report are those that were present at the time the borings were drilled. The depth and amount of water encountered in an open borehole largely depends on the permeability of the soils encountered at the boring location. In relatively impervious soils, such as clayey soils, a suitable estimate of the groundwater depths generally requires long-term monitoring.

Long-term monitoring of groundwater conditions via piezometers or groundwater monitoring wells was not performed during this study and was beyond the scope of this study. Long-term monitoring can reveal groundwater levels materially different than those measured in the borings.

Groundwater Fluctuations. Subsurface groundwater fluctuations can occur. Future construction activities can alter the surface and subsurface drainage characteristics of this site. Seasonal variations, temperature, land-use, proximity to water bodies, and rainfall can also influence groundwater levels. UES recommends that the contractor verifies the groundwater elevation before construction starts.

4.4 Seismic Site Classification

The Site Class assigned for seismic design considers various factors, such as the soil profile (whether it's soil or rock), shear wave velocity, and strength, averaged over a depth

For Refe ren ce of 100 feet. Since the borings did not reach depths of 100 feet, UES made determinations under the assumption that the subsurface materials beneath the borehole bottoms resembled those encountered at the termination depth and/or based on our experience with the subsurface conditions near the site. Following the guidelines outlined in Section

1613.3.2 of the 2018 International Building Code and Table 20.3-1 in the 2010 ASCE-7, UES recommends using Site Class E (very soft soil) for seismic design purposes at this location.

5.0 LABORATORY TESTING

UES performed laboratory tests, as appropriate, to define pertinent engineering characteristics of the soils encountered. The laboratory tests are performed in general accordance with ASTM or other applicable standards. Test results are included at the respective sample depths on the boring logs or separately tabulated herewith, as appropriate. Laboratory tests and procedures performed for this geotechnical study are summarized in the following table.

Summary of Laboratory Tests and Procedures

Test Procedure Description

ASTM D2487 Classification of Soils for Engineering Purposes (USCS)

ASTM D2488 Description and Identification of Soils (Visual-Manual Procedure)

ASTM D2216 Determination of Water (Moisture) Content of Soil and Rock by Mass

ASTM D4318 Liquid Limit, Plastic Limit, and Plasticity Index of Soils

ASTM D1140 Amount of Material in Soils Finer than the No. 200 (75-μm) Sieve

6.0 RECOMMENDATIONS

6.1 Existing Fill, Soft Soils and Demolition

As previously discussed, existing fill was encountered in all borings to various depths between 3 and 9 feet below the ground surface. Further discussion regarding this material is provided below.

Soft soils were encountered at depths up to 48 feet in both of the amphitheater borings, Borings B-101 and B-102, and near the surface in bio-infiltration detention pond area, Borings D-1 through D-3. The presence of these soils will likely necessitate remediation prior to paving activities and may restrict shallow foundation dimension and bearing capacities as discussed in the following sections of this report.

Existing pavement is present in the central portion of the site and will be demolished prior to new construction.

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6.1.1 Existing Fill

Existing Fill. Existing fill was encountered in all borings at various depths up to 9 feet.

Based on the results of the field and laboratory testing, the existing fill appears to have been placed with some level of compactive effort. However, documentation regarding the placement and compaction of the fill material was not available at the time of this report and should be considered as uncontrolled fill. Uncontrolled fill is generally not considered suitable for support of foundations or floor slabs due to the risk of under-compacted zones resulting in failures of weak soil and/or indeterminate levels of settlement. Any existing uncontrolled fill should be removed from the building pad areas in its entirety, and any areas sensitive to settlement, and replaced with engineered fill as recommended in Section 6.4.6. The excavated materials may be suitable for reuse as engineered fill provided they are free of organics, boulders, rubble, and other debris, and meet the criteria for the appropriate fill type. The lateral extent, depth and nature of the existing fill are not known. Test pits could be performed prior to construction to verify the presence, lateral extent, depth, and nature of the existing fill materials. UES can provide this service if desired.

6.1.2 Demolition

Applicability. Recommendations in this section apply to the removal of any existing foundations, utilities or pavement which may be present on this site.

General. Special care should be taken in the demolition and removal of existing floor slabs, foundations, utilities and pavements to minimize disturbance of the subgrade.

Excessive disturbance of the subgrade resulting from demolition activities can have serious detrimental effects on planned foundation and paving elements.

Existing Utilities. Existing utilities and bedding to be abandoned should be completely removed. Existing utilities and bedding may be abandoned in place if they do not interfere with planned development. Utilities which are abandoned in place should be properly pressure-grouted to completely fill the utility.

Backfill. Excavations resulting from the excavation of existing foundations and utilities should be backfilled in accordance with Section 6.4.6.

Other Buried Structures. Other types of buried structures (wells, cisterns, etc.) could be located on the site. If encountered, UES should be contacted to address these types of structures on a case-by-case basis.

6.2 Potential Movement of Expansive Soil

Estimated Potential Movement. Our findings indicate that the subsurface soils at the site are low in plasticity in the amphitheater area (Borings B-101 and B-102) while moderate to high in plasticity clay soils were encountered to a depth of about 3 feet in Borings D-1 and D-3. It is estimated that grade supported improvements within a finish elevation

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Harbor Point West March 30, 2026 within 1 to 2 feet of existing grade, at the time of our exploration, could experience post construction movements due to shrinking and swelling of expansive soils (active clays) of about 1 inch or less in the area of the earthen mound amphitheater and movements of about 1 ½ inches in the area of Borings D-1 and D-3. For the purpose of this report, movement due to shrinking and swelling of active clays will be referred to as potential vertical movement (PVM).

Method of Estimation. The potential vertical rise (PVR) was estimated in general accordance with methods outlined by Texas Department of Transportation (TxDOT) Test Method Tex-124-E, from results of absorption swell tests, and engineering judgment and experience. The estimated PVR was calculated assuming the moisture content of the in-situ soil within the active zone of seasonal moisture content change varies between a "dry" condition and a "wet" condition as defined by Tex-124-E. Also, it was assumed a 1 psi surcharge load from the floor slab acts on the subgrade soils. Movements exceeding our estimates could occur if positive drainage of surface water is not maintained or if soils are subject to an outside water source, such as leakage from a utility line or subsurface moisture migration from off-site locations.

Assumptions. PVR was estimated based on the assumption that at least 1 foot of fill will be placed to raise site grades and any fill used to raise grades will consist of onsite or similar soil with a plasticity index (PI) of 20 or less. The use of fill material with a PI greater than 20 could result in potential movements exceeding our estimates.

6.2.1 Expansive Soil Mitigation

Our findings indicate potential movements of the subsurface due to shrinking and swelling of active clays could be reduced to about one inch using the technique of removal and replacement with select fill to a depth of 18 inches below exist grade for improvements where grade adjustments are minimal. In areas where at least 4 feet of new fill is planned, the resultant PVM is estimated to be on the order of 1 inch; therefore, removal and replacement of the fat clay soils would not be necessary in these areas.

UES should be notified if grading will be different than assumed as additional analyses and recommendations could be required.

Risk Considerations. In choosing any of the recommended techniques for soil movement reduction, the Client is accepting some post construction movement of grade supported structures (about 1 inch). While structures can be designed to maintain structural integrity for a given level of movement, some degree of cosmetic distress manifesting in: cracks, unevenness of floor slabs, differential movements, etc., associated with about 1 inch of movement should be expected. If some level of movement and associated risk is not acceptable, it will generally be required to structurally suspend the floor slab completely above the ground surface using a deep foundation system, out of contact with the expansive soils. Recommendations for a structurally suspended floor slab are provided in Section 6.5.2.

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Harbor Point West March 30, 2026

6.3 Settlement Estimates of Earthen Mound

Based on information provided by Richter Architects at the time of the proposal, we understand that the earthen amphitheater will be crescent-shaped and approximately 200 feet in length, with a maximum height of 8 feet. A stacked concrete block retaining wall is planned at the amphitheater’s north end, while a 4H:1V slope is planned at the south end.

The width of the mound was not provided at the time of this report. We understand that materials excavated from the bio-infiltration detention basin areas is planned to be used as fill for the earthen mound structure.

Based on the soil encountered and our analysis, an earthen mound approximately 40 feet wide and 8 feet high producing a sustained ground pressure of 1,200 psf is expected to produce approximately 1.5 and 3 inches of long-term settlement below the edge and center of the mound, respectively.

Recommendations for reducing Settlement: Should the anticipated settlement, or differential settlement, exceed design tolerances, consideration could be given to utilizing ground improvement such as aggregate piers in combination with a load transfer platform.

Alternatively, the mound area could be surcharged with additional soil stockpile to induce further settlement and reduce the time to reach a tolerable percentage. However, with this option, wick drains would likely be required to reduce the time to achieve the desired settlement to fit the construction schedule. Further discussion regarding aggregate piers is provided in Section 6.5.1 of this report as this ground improvement option could be employed to support the stacked concrete block wall.

Depth of Improvement. Our findings indicate potential movements of the subsurface could be reduced to about 1 inch by removing the existing expansive clay soils and replacing them with select fill to a depth below existing site grades as summarized in the following table.

Summary of Subgrade Improvement Using Select Fill

Target PVR (inches) Removal and Replacement Depth (feet) 1,2,3

1 1.5

Notes:

1. Estimated depth measured below existing grade,

2. Select fill shall be as described in Section 6.4.6

3. Native subgrade to receive select fill should be scarified to a depth of 6 inches and compacted to 95 percent of the material’s maximum standard Proctor dry density (ASTM D-698) at or above the optimum moisture content.

Lateral Extents of Improvement. The recommended depth of non-expansive fill should extend throughout the entire structure and at least 5 feet horizontally beyond the perimeter of any structures, and below any additional flatwork for which it is desired to reduce movements.

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6.4 Earthwork

Variations in subsurface conditions could be encountered during construction. To permit correlation between test boring data and actual subsurface conditions encountered during construction, it is recommended a registered Professional Engineering firm be retained to observe construction procedures and materials.

Some construction problems, particularly degree or magnitude, cannot be reasonably anticipated until the course of construction. The recommendations offered in the following paragraphs are intended not to limit or preclude other conceivable solutions, but rather to provide insight based on our experience and understanding of the project characteristics and subsurface conditions encountered in the borings.

6.4.1 Excavation Safety Considerations

Excavation Safety. The contractor is responsible for designing any excavation slopes, temporary sheeting or shoring. Design of these structures should include any imposed surface surcharges. Construction site safety is the sole responsibility of the contractor, who shall also be solely responsible for the means, methods and sequencing of construction operations. The contractor should also be aware that slope height, slope inclination or excavation depths (including utility trench excavations) should in no case exceed those specified in local, state and/or federal safety regulations, such as OSHA Health and Safety Standard for Excavations, 29 CFR Part 1926, or successor regulations.

Stockpiles should be place well away from the edge of the excavation and their heights should be controlled so they do not surcharge the sides of the excavation. Surface drainage should be carefully controlled to prevent flow of water over the slopes and/or into the excavations. Construction slopes should be closely observed for signs of mass movement, including tension cracks near the crest or bulging at the toe. If potential stability problems are observed, a geotechnical engineer should be contacted immediately. Shoring, bracing or underpinning required for the project (if any) should be designed by a professional engineer registered in the State of Texas.

Applicability. Recommendations in this section apply to short-term construction-related excavations for this project with excavation depth less than 20 feet. Recommendations provided herein are not valid for any long-term or permanent slopes on-site. Stability of long-term unprotected slopes will require much flatter slopes. Slope protection for excavations greater than 20 feet should be designed and sealed by a professional engineer registered in the State of Texas.

Short-Term Sloped Excavations. All short-term sloped construction excavations on-site should be designed in accordance with Occupational Safety and Health Administration (OSHA) excavation standards. The following table provides a summary of the OSHA Soil Type Classification based on the soils encountered at the boring location.

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Harbor Point West March 30, 2026

Soil Type Classification Table

Depth (feet, bgs) Soi Description OSHA Soil Type Classification

0 to 20 Non-Cohesive Soil Above Water

Table, and all Soil Below The Water Table

Type C

The contractor’s “competent person” shall make the final determination of the OSHA Soil Type during excavation of the soils at the jobsite. The maximum allowable slopes during construction for soil OSHA soil types are provided in the following table.

Guidelines for Maximum Allowable Slopes Less Than 20-feet Deep

Soil Type Max. Allow. Slopes for Excavations

Type B 1 Horizontal : 1 Vertical

Type C 1.5 Horizontal : 1 Vertical

Shored Excavations. As an alternative to sloped excavations, vertical short-term construction excavations may be used in conjunction with trench boxes or other shoring systems. Shoring systems should be designed using an equivalent fluid weight of 65 pounds per cubic foot (pcf) above the groundwater table and 95 pcf below the groundwater table. Surcharge pressures at the ground surface due to dead and live loads should be added to the lateral earth pressures where they may occur. Lateral surcharge pressures should be assumed to act as a uniform pressure along the upper 10 feet of the excavation based on a lateral earth coefficient of 0.5. Surcharge loads set back behind the excavation at a horizontal distance equal to or greater than the excavation depth may be ignored. We recommend that no more than 200 feet of unshored excavation should be open at any one time to prevent the possibility of failure and excessive ground movement to occur. We also recommend that unshored excavations do not remain open for a period of time longer than 24 hours.

Limitations. Recommendations provided herein assume there are no nearby structures or other improvements which might be detrimentally affected by the construction excavation. Before proceeding, we should be contacted to evaluate construction excavations with the potential to affect nearby structures or other improvements.

Excavation Monitoring. Construction excavations and their related safety are the responsibility of the Contractor. Excavations should be monitored and documented by a competent professional to confirm site soil conditions consistent with those encountered in the borings drilled as part of this study. Discrepancies in soil conditions should be brought to the attention of UES for review and revision of recommendations, as appropriate.

6.4.2 Site Preparation and Proofroll

Site Clearing. In the area of planned improvements, all concrete, trees, stumps, brush, debris, septic tanks, abandoned structures, roots, vegetation, rubbish and any other undesirable matter should be removed and properly disposed.

Proofroll. Building pad and paving subgrades should be selectively proofrolled with

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Harbor Point West March 30, 2026 approved construction equipment to locate areas of soft or loose subgrade, or otherwise unstable soils. Care should be taken during proofrolling operations as excessive equipment operations may lead to degradation to the subgrade soils.

In areas to be cut, the proofroll should be performed after the final grade is established.

In areas to be filled, the proofroll should be performed prior to fill placement. Areas of loose or soft subgrade encountered during the proofroll should be removed and replaced with properly compacted fill. Prior to placement of any fill, the exposed soil subgrade should then be scarified to a minimum depth of 6 inches and recompacted as outlined in Section 6.4.6.

6.4.3 Construction Considerations

Soft Sandy/Silty Surficial Soils. Sandy silty soils were encountered at or near the ground surface at this site. These soils are susceptible to strength degradation with changes in moisture. The presence of surface water due to precipitation or groundwater may result in a decrease in the ability to compact and work with the soil. It is common for these soils to pump when subjected to high levels of moisture. In addition, these soils located at and near the ground surface will allow surface water to infiltrate until the water becomes perched on a less permeable layer at depth. As such, construction difficulties should be anticipated, especially during the wet season or immediately after rain events. Although having a thin layer of non-plastic or low plasticity soils overlying cohesive soils is typical of this geologic region, our experience suggests that the local contractors find these materials troublesome and can often be the source of change orders, construction delays, and budget over runs. Soils of this type are especially prone to requiring the implementation of wet weather/soft subgrade recommendations provided in this report.

Maintenance of Subgrade during Construction. While the exposed subgrade is expected to remain relatively stable initially, unstable conditions may arise during general construction activities, particularly if the soil is exposed to wet weather conditions and repetitive construction traffic. The use of lighter construction equipment can help minimize disturbance to the subgrade. In the event of unstable conditions, stabilization measures will be necessary. After grading is completed, it is crucial to maintain the moisture content of the subgrade before proceeding with pavement construction.

Minimizing construction traffic over the finished subgrade is advisable. If the subgrade becomes desiccated, saturated, or disturbed, the affected material should either be removed or treated by scarification, moisture conditioning, and recompaction before pavement construction begins. UES should be retained to observe earthwork and to perform necessary tests and observations during subgrade preparation.

Wet Weather/Soft Subgrade. Soft and/or wet surface soils may be encountered during construction, especially following periods of wet weather. Wet or soft surface soils can present difficulties for compaction and other construction equipment. If specified compaction cannot be achieved due to soft or wet surface soils, one of the following corrective measures will be required:

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Harbor Point West March 30, 2026

1. Removal of the wet and/or soft soil and replacement with properly compacted fill,

2. Treatment of the wet and/or soft soil with appropriate chemical agent, or

3. If allowed by the schedule, and weather permitting, drying by natural means.

Chemical treatment is usually the most effective way to improve soft and/or wet surface soils. UES should be contacted for additional recommendations if chemical treatment is planned due to wet and/or soft soils.

Fill on Existing Slopes. If fill is to be placed on existing slopes (natural or constructed) steeper than six horizontal to one vertical (6:1), the fill materials should be benched into the existing slopes in such a manner as to provide a minimum bench-key width of five (5) feet. This should provide a good contact between the existing soils and new fill materials, reduce potential sliding planes, and allow relatively horizontal lift placements.

6.4.4 Grading, Drainage and Other Considerations

Efforts should be made to minimize the excessive wetting or drying of the underlying soil, as it can lead to swelling and shrinkage of these soil layers. Standard construction practices of providing good surface water drainage should be used. A positive slope of the ground away from any foundation should be provided. Ditches or swales should be provided to carry the run-off water both during and after construction. Stormwater runoff should be collected by gutters and downspouts and should discharge away from the buildings.

In areas with pavement or sidewalks adjacent to the structure, a positive seal must be maintained between the structure and the pavement or sidewalk to minimize seepage of water into the underlying supporting soils. Post-construction movement of pavement and flatwork is common. Regular maintenance should include examination of all joints in paving and sidewalks, etc. as well as re-sealing where necessary.

Since granular bedding backfill is used for most utility lines, the backfilled trench should not become a conduit and allow access for surface or subsurface water to travel toward the new structures. Concrete cut-off collars or clay plugs should be provided where utility lines cross building lines to prevent water from traveling in the trench backfill and entering beneath the structures.

Root systems from trees and shrubs can draw a substantial amount of water from the clay soils at this site, causing the clays to dry and shrink in excess of our estimates. This could cause settlement beneath grade-supported slabs such as floors, walks and paving.

Trees and large bushes should be located a distance equal to at least one-half their anticipated mature height away from grade slabs. Lawn areas should be watered moderately, without allowing the clay soils to become too dry or too wet.

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6.4.5 Groundwater Control

Groundwater was encountered at depths of about 6 to 18 feet below the ground surface in all borings across the site. However, seasonal fluctuations and/or unforeseen environmental conditions may result in water being encountered at shallower depths.

This groundwater could be encountered in excavations or during grading required for building pad and/or generally site preparation. We recommend the Contractor provide a line item for dewatering in the bid package in case dewatering is required. Test pits should be performed just prior to construction to verify groundwater conditions.

The contractor is typically responsible for designing, installing and maintaining a dewatering system for groundwater control and taking precautions to avoid distress to nearby existing structures, resulting from dewatering. Dewatering systems should be designed, installed and monitored by personnel qualified and experienced with dewatering soils. We recommend the Contractor consider retaining a dewatering expert to assist in identifying, implementing and monitoring the most suitable and cost-effective method to control groundwater. The following is intended to provide general guidance to the Contractor for dewatering systems.

Generally, the groundwater depth should be lowered to a depth of at least 3 feet below the planned excavation bottom to provide a firm working surface. Extended and/or extensive dewatering can result in settlement of existing structures in the vicinity; the Contractor should take necessary precautions to monitor and minimize the effects on these structures.

6.4.6 Fill Compaction

Select Fill. Select fill used as non-expansive fill should consist of soil with a liquid limit of 35 or less and a Plasticity Index between 8 and 20. The select fill soils shall have a minimum of 35 percent passing the #200 sieve and a maximum of 65 percent passing the #200 sieve. The select fill shall have no soil particles exceeding 1½ inches.

The select fill should be placed in loose lifts not exceeding 8-inches and should be compacted to at least 95 percent maximum dry density (per ASTM D-698) at a moisture content between optimum and 4 percent above optimum moisture content. The plasticity index and liquid limit of material used as select fill material should be routinely verified during placement using laboratory tests. Visual observation and classification should not be relied upon to confirm the material to be used as select fill material that satisfies the required Atterberg limit criteria.

Flexible Base Material. Flexible base material used in pavement areas should consist of material meeting the requirements of TxDOT Standard Specifications Item 247, Type A, Grade 1-2. The flexible base should be compacted to at least 98 percent of standard Proctor maximum dry density (ASTM D 698) and within the range of 2 percentage points below to 2 percentage points above the material's optimum moisture content.

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General Fill. General fill may be placed in improved areas outside of building areas.

General fill should consist of material approved by the Geotechnical Engineer with a liquid limit less than 50. General fill should be placed in loose lifts not exceeding 8 inches and should be uniformly compacted to a minimum of 95 percent maximum dry density (per ASTM D-698) at or above the optimum moisture content. The subgrade to receive general fill should be scarified to a depth of 6 inches and compacted to at least 95 percent maximum dry density (per ASTM D-698) and at or above the optimum moisture content.

Fill Restrictions. Select fill and general fill should consist of those materials meeting the requirements stated. Fill soils should not contain material greater than 4 inches in diameter, debris, vegetation, waste material, environmentally contaminated material, or any other unsuitable material.

Unsuitable Materials. Materials considered unsuitable for use as select fill or general fill include low and high plasticity silt (ML and MH), silty clay (CL-ML), organic clay and silt (OH and OL) and highly organic soils such as peat (Pt). These soils may be used for site grading and restoration in unimproved areas as approved by the Geotechnical Engineer.

Soil placed in unimproved areas should be placed in loose lifts not exceeding 10 inches and should be compacted to at least 92 percent maximum dry density (per ASTM D-698) and at a moisture content within ±4 percentage points of optimum.

Fill Compaction Testing Guidelines. Field compaction and classification tests should be performed by UES. Compaction tests should be performed in each lift of the compacted material. We recommend the following minimum soil compaction testing be performed:

one test per lift per 2,500 square feet (SF) in the area of the building pad, one test per lift per 5,000 SF outside the building pad, and one test per lift per 100 linear feet of utility backfill, or a minimum of three tests per lift. If the materials fail to meet the density or moisture content specified, the lift should be reworked as necessary to obtain the specified compaction. Classification confirmation inspection/testing should be performed daily on select fill materials (whether on-site or imported) to confirm consistency with the project requirements. The testing frequency recommended herein can be altered (increased or decreased) at the discretion of the geotechnical engineer of record.

6.4.7 Utilities

Bedding. Pipe bedding and pipe-zone backfill for underground utilities should meet the requirements of the pipe manufacturer. If no manufacturer requirement exists, then pipe bedding should be placed in accordance with applicable municipal or TxDOT requirements. Unless specified otherwise, the pipe-zone generally consists of all materials surrounding the pipe in the trench from six (6) inches below the pipe to 12 inches above the pipe. Since granular bedding backfill is used for most utility lines, measures should be taken to ensure the backfilled trench does not become a conduit that allows access for surface or subsurface water to travel toward and beneath the new structure.

Concrete cut-off collars or clay plugs should be provided where utility lines cross building lines to prevent water from traveling in the trench backfill and entering beneath the structure. At least 1 foot of soil cover should exist between concrete plugs and structural

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Harbor Point West March 30, 2026 elements.

Backfill. The trench backfill for utilities should be properly placed and compacted as outlined in Section 6.4.6 and in accordance with requirements of local City standards.

Utility backfill in the building pad should be placed in accordance with applicable requirements for the building pad.

Trench Settlement. Even if fill is properly compacted, fills in excess of about 5 feet are still subject to settlements over time of up to about 1 to 2 percent of the total fill thickness.

This should be considered when designing pavements over utility lines and/or other areas with deep fills. Where utility lines are deeper than 5 feet, the backfill below a depth of 5 feet, consideration should be given to utilizing crushed aggregate, cement stabilized sand or flowable fill to reduce settlement. If materials requiring mechanical compaction for densification are utilized, compaction specifications should be increase to 100 percent of the material’s maximum dry density as determine by the standard Proctor.

Trench Excavation. If utility trenches or other excavations extend to a depth of 5 feet or more below construction grade, the contractor or others shall be required to develop an excavation safety plan to protect personnel entering the excavation or excavation vicinity.

The collection of specific geotechnical data and the development of such a plan, which could include designs for sloping and benching or various types of temporary shoring, is beyond the scope of this study. Any such designs and safety plans shall be developed in accordance with current OSHA guidelines and other applicable industry standards.

6.5 Stacked Block Wall and Shade Structure Foundation

Systems

Appropriate Foundation Types.