LNAA-CO-26-001 Package B Elevated Pedestrian Walkway Geotechnical Report.pdf

GEOTECHNICAL ENGINEERING REPORT

Lehigh Valley International Airport Elevated Passenger Connector Allentown, Pennsylvania Airport Design Consultants, Inc.

Schnabel Reference 23150062.001 February 16, 2026

February 16, 2026

Tracy Hollida, PE

6031 University Boulevard, Suite 330 Ellicott City, MD 21043

Subject: Geotechnical Engineering Report – Elevated Passenger Connector Lehigh Valley International Airport, Allentown, Pennsylvania (Schnabel Reference 23150062.001)

Dear Ms. Hollida:

SCHNABEL ENGINEERING, LLC is pleased to submit our geotechnical engineering report for this project. This study was performed in accordance with our Agreement Work Order No. 2, executed on December 11, 2025, and supplemental Agreement Work Order No. 2A, executed on November 11, 2025.

ADCI engaged Schnabel under Task 2023-27 to oversee the geotechnical investigation, develop 30% conceptual design recommendations, prepare a geotechnical report, and complete 60 to 100% micropile foundation design plans and specifications. ADCI has also engaged TLC Engineering Solutions (TLC) and The Sheward Partnership, LLC (TSP) as structural and architectural designers, respectively.

We appreciate the opportunity to be of service for this project. Please call us if you have any questions regarding this report.

Sincerely, SCHNABEL ENGINEERING, LLC

Stephen J. Welsh, PE Associate

Jeremy J. Brown, PE Senior Associate

JFH:NCS:SJW

LVIA Elevated Passenger Connector

February 16, 2026 Page i Schnabel Engineering, LLC Project 23150062.001 ©2026 All Rights Reserved

GEOTECHNICAL ENGINEERING REPORT

ELEVATED PASSENGER CONNECTOR

LEHIGH VALLEY INTERNATIONAL AIRPORT

ALLENTOWN, PENNSYLVANIA

TABLE OF CONTENTS

1.0 PROJECT DESCRIPTION

1.1 Regional Geology

2.0 EXISTING TERMINAL FOUNDATIONS DOCUMENT REVIEW

3.0 SUBSURFACE EXPLORATION AND LABORATORY TESTING PROGRAM

3.1 Subsurface Exploration Methods

3.1.1 Test Borings

3.1.2 Test Pits

3.2 Soil Laboratory Testing

3.2.1 Index Testing

3.2.2 Direct Shear Testing

3.2.3 Rock Testing

4.0 SITE GEOLOGY AND SUBSURFACE CONDITIONS

4.1 Site Geology

4.1.1 Variation of Subsurface Conditions Due to Karst

4.2 Generalized Subsurface Stratigraphy

4.2.1 Ground Cover

4.2.2 Stratum A: Fill

4.2.3 Stratum B: Residual Soils

4.2.4 Stratum C: Disintegrated Rock

4.2.5 Stratum D: Epler Formation Bedrock

4.3 Groundwater

4.4 Seismic Site Classification

5.0 KARST HAZARDS AND MITIGATION RECOMMENDATIONS

5.1 Karst Hazards

5.2 Karst Mitigation Recommendations

5.2.1 Sinkhole Repair

5.3 Ground Improvement: Limited Mobility Grout

6.0 GEOTECHNICAL RECOMMENDATIONS

6.1 Elevated Passenger Connector Foundations

6.1.1 Micropile Design

6.1.2 Existing Terminal Building Footings

6.2 Contractor-Designed Items

6.3 Temporary Excavation Support

6.4 Elevator Walls

6.5 Construction Sequencing

6.6 Instrumentation and Monitoring

February 16, 2026 Page ii Schnabel Engineering, LLC

7.0 CONSTRUCTION CONSIDERATIONS

7.1 Site Grading and Earthwork

7.2 Compacted Fill

7.2.1 Rock Excavation

7.3 Micropile Installation Observation by Foundation Designer (Schnabel)

7.4 Engineering Services During Construction

7.5 General Specification Recommendations

8.0 LIMITATIONS

Test Pits Standard Penetration Test Results

LIST OF TABLES

Table 6.1: Conceptual Micropile Allowable Axial Capacities and Bond Length Table 6.2: Existing Spread Footings Loading Table 6.3: Recommended Design Parameters for Walls – At-Rest Table 7.1: Estimated Top of Rock Elevations

LIST OF FIGURES

Figure 1: Boring Location Plan Figure 2: Geology Map Figure 3: Karst Features and Reference Map

APPENDICES

Appendix A: As-Built Terminal Plans Appendix B: Subsurface Exploration Data Appendix C: Laboratory Results

February 16, 2026 Page 1 Schnabel Engineering, LLC

1.0 PROJECT DESCRIPTION

Lehigh Valley International Airport (LVIA) is a non-hub primary commercial service facility located in Allentown, Lehigh County, Pennsylvania. LVIA is situated approximately 50 miles north of Philadelphia and 75 miles west of New York City. LVIA was originally constructed in 1929 and is currently owned and operated by the Lehigh-Northampton Airport Authority (LNAA). LVIA serves all aviation markets, including general aviation, business, military, and commercial (passenger and cargo).

LVIA has seen a growing volume of passenger-commercial enplanements, and current projections indicate the number will continue to rise. The existing short- and long-term parking lots are at or near capacity during times of heavy air traffic, and LVIA has had to use an overflow lot to accommodate traveler parking. LNAA has initiated a project at LVIA to increase the existing parking capacity at the passenger terminal. We understand LNAA is proceeding with a ±1,250 parking space garage (a net gain of ±975 spaces) alternative.

The proposed parking garage will be located within the existing short-term parking area and will consist of five levels, with the lowest level at grade. An elevator lobby is located at the north end (terminal side) of the garage and will be connected to the terminal via an elevated pedestrian connector structure (connector) spanning over the existing departure roadway. The proposed connector structure spans over the existing departure embankment with connector column foundations located at varying grades.

Proposed connector column foundations are located south of the departure roadway embankment, at the existing short-term parking lot grade, and the northern (terminal side) pier foundations are at the crest of and within the departures roadway embankment. Combined foundations will support two columns for the connector and garage-elevator lobby; one combined foundation is included in the garage design package and the second combined foundation is included in the connector design package. The bottom of the proposed elevator structure (terminal side) is at the existing arrivals grade at the toe base of the departures roadway embankment. Proposed connector foundations on the terminal side are in close proximity to the existing terminal buttress foundations. The existing terminal buttress Foundations 3, 4, and 5 are supported on concrete pedestal foundations bearing on rock. The proposed connector layout is shown in Figure 1, Boring Location Plan, included at the end of this report. Cross-sections showing the foundations and subsurface soil/rock conditions along the passenger connector alignment and perpendicular to the existing terminal buttresses are included in Appendix B.

This report is limited to geotechnical recommendations for the elevated passenger connector only;

recommendations for the parking garage structure are part of a separate design contract.

1.1 Regional Geology

The site is mapped as being underlain by bedrock of the Epler Formation that consists of carbonate-based dolomite rock that is susceptible to solution features resulting in ground subsidence and sinkholes, and/or a highly irregular bedrock surface. Ground subsidence caused by the dissolution of carbonate rock and subsequent loss of soil is referred to as karstic activity, or karst. Karst feature maps from the Pennsylvania Department of Conservation and Natural Resources show surface depressions and sinkholes located within and around the airport. Based on our experience at the airport, the site has a history of sinkholes and surface depressions. A Geologic Map of the site is included in Figure 2.

February 16, 2026 Page 2 Schnabel Engineering, LLC

2.0 EXISTING TERMINAL FOUNDATIONS DOCUMENT REVIEW

Schnabel reviewed the existing terminal construction documents dated September 1972 and the As-Built Plan dated April 25, 1974. Modifications to the design were required due to karst conditions encountered during construction, which demonstrates the challenges in working within the site’s karstic geology. The existing terminal building is supported on three foundation types: (1) Type A and C foundations are spread footings on rock with a design bearing pressure of 15 ksf; (2) Type Aꞌ and Cꞌ foundations are spread footings bearing on soil with a 2.5 ksf bearing pressure; and (3) Type B foundations are supported on HP10 piles driven to refusal on bedrock. Modifications noted in the As-Built Plans include:

• Foundations at Columns B2, D8, and D9 were designed to be spread footings, and the As-Built Plans note the foundations consist of both spread footings and driven piles. Some of the foundation dimensions were also modified.

• Foundations at Columns B7, B10, and D6 were designed as driven piles, and the As-Built Plan indicate the foundations were constructed as combined footings and driven piles.

• Two sinkhole repairs are noted on the As-Built Plan, including an 11 cy repair near Column Line 2F and a 2 cy repair between Columns 10A to 10B and H to J.

The As-Built Plan is included in Appendix A. The proposed connector meets the existing terminal building at Columns 4B and 5B. These examples of foundation modifications during construction show the unpredictable nature of working within karst conditions at the site and how important it is to consider the feasibility of different foundation types in these conditions as well as the need to plan and account for modifications needed during construction.

3.0 SUBSURFACE EXPLORATION AND LABORATORY TESTING PROGRAM

Schnabel completed a two-phase geotechnical investigation for the connector consisting of a total of five geotechnical borings and three test pits. Phase 1 included two test borings in the departures roadway lane and Phase 2 consisted of three test borings and three test pits on the embankment slope between the arrivals and departures roadway lanes. The test pits were performed at existing terminal buttress foundations to compare field conditions with as-built plans.

3.1 Subsurface Exploration Methods

3.1.1 Test Borings

Schnabel’s subcontractor, Sano Drilling Inc. of Sewell, New Jersey, drilled two test borings under our supervision in Phase 1 on December 11 and 12, 2024, and three test borings in Phase 2 between August 29 and September 3, 2025. Standard Penetration Testing (SPT) was performed at selected depths in the borings. Appendix B includes specific observations, remarks, logs for the borings, and cross-sections;

classification criteria; drilling methods; and sampling protocols. Figure 1 indicates the approximate test boring locations. We will retain soil samples up to 45 days beyond the issuance of this report unless you request other disposition.

The SPT samples were obtained using a hydraulically driven automatic-trip hammer (ATH). Most correlations with SPT data are based on N-values collected with a safety hammer. The energy applied to the split-spoon sampler using the ATH is about 33% greater than that applied using the safety hammer, resulting in lower N-values. The hammer blows shown on the boring logs are uncorrected for the higher

February 16, 2026 Page 3 Schnabel Engineering, LLC energy; however, we correct SPT N-values for higher energy when using N-values in our analyses. Select samples were obtained with a smaller diameter (1 inch) split-spoon sampler. Blow counts required to advance the smaller samples are recorded on the logs, and applicable samples obtained with smaller diameter tooling are noted. Our analysis also accounted for varying hammer energies required to advance the different sample sizes.

3.1.2 Test Pits

Schnabel’s subcontractor, Sano Drilling, excavated Test Pits TP-1, TP-2, and TP-3, at existing terminal buttress foundations at Column Lines 3, 4, and 5, respectively, under our supervision on September 9, 2025. Appendix B includes specific observations, remarks, and logs for the test pits; classification criteria;

and excavation methods. Figure 1 indicates the approximate test pit locations.

3.2 Soil Laboratory Testing

AECOM Technical Services Inc. in Conshohocken, Pennsylvania, performed laboratory testing on select samples collected during the investigation. The testing aided in the classification of materials encountered in the subsurface exploration and provided data for use in the development of recommendations for design of foundations, earthwork, and below-grade walls. The results of the laboratory tests are included in Appendix C and are summarized for each stratum in the Site Geology and Subsurface Conditions section of this report. Selected test results are also shown on the boring logs in Appendix B.

3.2.1 Index Testing

We performed index testing on samples collected as part of the exploration to provide soil classifications and to provide parameters for use with published correlations with soil properties. Index testing included natural moisture content, Atterberg Limit, gradation, and one hydrometer test.

3.2.2 Direct Shear Testing

We performed direct shear testing on one soil specimen representing Stratum B to provide information regarding the shear strength of the soil encountered on site.

3.2.3 Rock Testing

We performed compression point load testing on four rock specimens representing Stratum D to provide information regarding the strength of the rock encountered on site.

4.0 SITE GEOLOGY AND SUBSURFACE CONDITIONS

4.1 Site Geology

A review of geologic information from the Pennsylvania Department of Conservation and Natural Resources indicates the project site is underlain by the Epler Formation of the Ordovician Period. The Epler Formation is described as a thick bedded, finely to very finely crystalline, medium gray limestone with yellow dolomitic laminae and interbedded medium, dark gray, finely crystalline dolomite that weathers yellowish gray. The Epler Formation can contain conglomerate, fossil fragments, and oolitic lenses. The thickness of the Epler Formation is noted as up to 800 ft (Markewicz and Dalton 1977). This formation generally has moderately abundant, open and steeply dipping, well to poorly developed fractures; is moderately resistant to weathering; can have a soil overburden of 80 ft or more; and typically has difficult excavation properties due to pinnacles (Geyer and Wilshusen 1982).

February 16, 2026 Page 4 Schnabel Engineering, LLC

4.1.1 Variation of Subsurface Conditions Due to Karst

The limestone and dolomite of the Epler Formation are carbonate bedrock. Carbonate bedrock is subject to dissolution. The dissolution typically results in highly variable subsurface conditions (both vertically and laterally) and commonly includes bedrock fractures adjacent to very hard rock; deep bedrock zones filled with soft soil adjacent to more shallow bedrock; overhanging ledge rock; pinnacled bedrock (i.e., the top of the intact rock surface can vary significantly over short distances); boulders; very soft soils weathered from the bedrock at the soil-bedrock interface; and solution features in the rock such as voids filled with soil, water, or air. These features are described as “karst” features.

Karst features, such as bedrock pinnacles, soft or loose material beneath firmer or stiffer soils, and deep, highly fractured, and weathered zones of bedrock were observed in the passenger connector borings. A Karst Features and Reference Map is included in Figure 3.

4.2 Generalized Subsurface Stratigraphy

We encountered the following stratigraphy during our exploration. We characterized the generalized subsurface stratigraphy based on the exploration and laboratory test data included in the appendices.

4.2.1 Ground Cover

Test Borings BB-3 and BB-4 were drilled within the departures roadway lane and encountered surficial ground cover consisting of 2 inches of bituminous asphalt, 6 inches of reinforced concrete, and 16 inches of gravel subbase. Test Boring BB-5 encountered 3 inches of mulch at the ground surface.

4.2.2 Stratum A: Fill

Fill soils were encountered in all test borings directly below the ground cover or at the existing ground surface at depths between 0 and 2 ft below existing ground surface and extended to depths between 5 and 17 ft below existing ground surface. The fill is generally associated with the existing departures roadway embankment and was described as brown, orange-brown, and yellow-brown sandy lean clay and lean clay (CL) with varying amounts of sand and gravel. Test boring BB-5 encountered fill described as brown poorly graded sand (SP). Limestone and concrete fragments were also observed within the fill soil. Uncorrected SPT N-values within the fill ranged from 5 to >50. Select soil samples from Stratum A were tested for moisture content, gradation, and Atterberg Limits. The reported natural moisture contents ranged between 7.1 and 19.6%; Liquid Limits ranged from 30 to 34; Plastic Limits ranged from 18 to 21;

and between 59.2 and 79.2% passed the No. 200 sieve. Hydrometer analysis on one sample reported 28% clay content.

4.2.3 Stratum B: Residual Soils

Residual soils are derived through the in-place physical and chemical weathering of the underlying rock.

The residual soils were encountered at depths of 5 to 17 ft and extended to depths ranging between 13 and 39 ft. Test Boring BB-2 encountered a very dense disintegrated rock material from 13 to 14 ft. The residual soils were generally described as brown and yellow-brown sandy silt (ML) and lean clay (CL) with varying amounts of sand. Generally, uncorrected N-values within the residual soil ranged from 2 to 11.

Select soil samples from Stratum B were tested for moisture content, gradation, and Atterberg Limits. The reported natural moisture contents ranged from 18.9 to 21.3%; all samples tested were found to be non-plastic; and 61 to 63.8% passed the No. 200 sieve. Direct shear testing was performed on one sample of residual soil.

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4.2.4 Stratum C: Disintegrated Rock

Disintegrated rock was observed in Boring BB-2 from 13 to 14 ft and overlying bedrock. The disintegrated rock was described as light brown and gray sand (SP) with N-values greater than 50. No laboratory testing was performed on samples from this stratum.

4.2.5 Stratum D: Epler Formation Bedrock

The dolomite bedrock of the Epler Formation was encountered in the borings underlying the fill and residual soil at depths ranging between 5.5 and 39 ft below existing grade and extending to the boring termination depths. The rock cores were generally described as light to dark gray limestone with streaks of white, medium strong to very strong, highly to slightly weathered, and intensely to slightly fractured.

Water return was generally not observed during rock coring, and a tool drop was observed during coring in BB-5, both of which further indicate the presence of fracturing, weathering, and/or voided rock conditions. Laboratory testing of rock samples of Stratum D indicates uniaxial compression strength (UCS) values ranging from 3,871 to 27,903 psi with an average of 13,497 psi. Evidence of karst bedrock was observed as demonstrated by the following list of encountered depths/elevations:

• Test Boring BB-1: Core barrel deflection at 6 ft (EL 361) in BB-1 due to possible rock pinnacle

• Test Boring BB-3: Core barrel breaking at 35 ft (EL ~342), potentially due to deflection on a rock pinnacle

• Test Boring BB-4: Core barrel deflection/wedging in rock at 41 ft (EL ~336) due to possible rock pinnacle

4.3 Groundwater

We monitored groundwater during drilling and obtained water readings during drilling and upon completion prior to backfilling the test borings. The borings were observed to be dry and groundwater was not observed during the exploration. We did not obtain long-term water level readings because the test borings were backfilled upon completion for safety.

The final design should anticipate the fluctuation of the hydrostatic water table depending on variations in precipitation, surface runoff, evaporation, leaking utilities, and similar factors.

4.4 Seismic Site Classification

We evaluated the Seismic Site Class and Seismic Site Coefficients for this project according to ASCE 7-

16. Our analysis indicates Site Class D based on corrected SPT N-values. The proposed structures are based on Risk Categories III and IV. We recommend the following mapped acceleration parameters:

• Short period parameter (Ss) of 0.169

• 1-second period parameter (S1) of 0.048

• Site amplification factor (Fa) of 1.6

• Site amplification factor (Fv) of 2.4

• Numeric seismic design value at 0.2 seconds (SDS) of 0.18

• Numeric seismic design value at 1.0 second (SD1) of 0.076

February 16, 2026 Page 6 Schnabel Engineering, LLC

5.0 KARST HAZARDS AND MITIGATION RECOMMENDATIONS

5.1 Karst Hazards

As discussed in Section 4.1, the site is underlain by carbonate bedrock that is susceptible to dissolution.

Karst activity resulting from the process of dissolution is a natural process that can be exacerbated by the construction of new features. The proposed development may exacerbate this risk of karst activity both short and long term.

By undertaking this project, Schnabel assumes the Owner’s understanding and acceptance of the risk of exposure to the potential for subsidence due to karst activity during the lifecycle of the proposed facility.

We anticipate three primary risks associated with the proposed project that are related to karst activity:

• Encountering highly variable top of rock surface, boulders, and bedrock pinnacles during construction

• The development of sinkholes and subsidence during construction

• The development of sinkholes and subsidence after construction, and their impact to completed work

Closed depressions and sinkholes are the two main types of cover (ground) subsidence that are visible at the surface in karst areas. Both features, discussed below, are closed drainage systems, meaning that water flows into them and into the underlying soil and rock, which can exacerbate the subsidence.

• Closed Depressions: Closed depressions typically form where granular materials spall or settle into a void gradually, like sand in an hourglass moving downward. Closed depressions generally develop at the ground surface slowly, and there is not a collapse, soil scarp, or visible throat.

• Sinkholes: Sinkholes generally develop in the subsurface over some time period, where material spalls into a void in the underlying rock, sometimes called a “throat,” and a void propagates upward in the soil. Eventually the void reaches a point where the cover soil roof collapses, resulting in a hole at the ground surface with fresh soil exposed at the sidewall or scarp. If rock is shallow, the throat may be visible within the fresh scarp. Over time, if a sinkhole is not remediated, the edges of the feature may soften and collapse inward and be indistinguishable from a closed depression.

The risk of sinkhole development can be elevated during construction when surface drainage is abnormal and changes in stresses on the soil occur from cutting/filling and from the load of construction equipment.

Following construction, the risk of sinkholes can also be elevated due to changes in the soil cover (i.e., the reduction in the thickness of the soil cover above bedrock can result in more rapid subsurface erosion and infiltration) and in the drainage regime (i.e., concentrated water flow and infiltration of surface water runoff from stormwater facilities [pipes, basins, etc.]).

The formation of sinkholes during and following construction should be anticipated. Recommendations to reduce the risk of and remediate against the effects of karst activity are provided below.

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5.2 Karst Mitigation Recommendations

The depth, size, shape, and nature of the subsidence caused by karst activity can vary considerably. In some cases, the bedrock surface is exposed, and in other cases only soil is visible. Thus, each subsidence feature should be repaired in accordance with recommendations from the Geotechnical Engineer. As such, the Geotechnical Engineer should be notified if subsidence develops, as each remediation event will depend on multiple factors, including depth to bedrock, size of the subsidence feature, and location with respect to critical structures. Recommendations for repairs are provided below.

5.2.1 Sinkhole Repair

When sinkholes or soft zones are observed during construction, soft or collapsed soils should be excavated in an attempt to reveal the throat of the sinkhole. Water may be used to wash pinnacles, open throats, and evaluate drainage. The throat should be plugged as recommended by the Geotechnical Engineer. A description of the sinkhole repair details and logic is as follows:

• Sinkhole Repair or Soft Zone in Soil: In areas where a defined sinkhole throat in rock is not observed, loose materials should be removed and a woven geotextile placed to contain fill materials used to repair the area. Crushed stone may be used to stabilize the base of these areas prior to placing capping soils. Place geotextile over stone, then place low permeability soil defined as a minimum 65% passing the No. 200 sieve, a minimum Liquid Limit of 25, and a minimum Plasticity Index of 10.

• Sinkhole Repair in Rock: Where competent rock sides are encountered and a clear throat of the sinkhole can be identified, the throat should be filled with crushed rock fill followed by the placement of a low strength concrete seal to limit future infiltration. The required cover materials (asphalt, concrete, soil cover with topsoil/seed, etc.) can be placed once the concrete cap cures.

5.3 Ground Improvement: Limited Mobility Grout

Limited mobility grout (LMG) is a ground improvement technique that can be used to: (1) fill voids/ displace soft soils, (2) densify the soils to improve the bearing capacity, and (3) plug sinkhole throats at the bedrock surface to prevent downward migration of soil into bedrock voids. LMG uses a low mobility (low slump) cement-based grout to densify soil through controlled injection and radial expansion. Grouting is preferable in areas where there are deep and wide zones of unsuitable material. As part of a grouting program, probe holes are usually extended several feet into rock (or some pre-determined minimum depth) to delineate soft zones and/or voids within the rock mass. Grouting to remediate larger areas is typically performed in a grid pattern of primary holes, followed by secondary (and possibly tertiary) holes at a tighter spacing where warranted by the volume of grout takes observed in the primary holes. To limit grout takes, perimeter holes are often completed first to act as a barrier before interior holes are grouted to achieve closure. Grouting to remediate isolated areas encountered during micropile drilling can also be performed. Once the LMG cures, the micropile can be re-drilled through the remediated area. Based on conditions observed in Borings BB-3 and BB-4, there is a potential that LMG may be required to treat isolated areas of the site for the elevated passenger connector.

We recommend that the contract includes provisions for this remediation method in the event it is deemed necessary by the Geotechnical Engineer during construction. Micropiles and LMG are installed with similar equipment; therefore, the foundation Contractor should be capable of performing LMG without

February 16, 2026 Page 8 Schnabel Engineering, LLC incurring significant delays. A location-specific grouting program and layout would be developed based on karst feature sizes and depths identified in the field if this is deemed necessary.

6.0 GEOTECHNICAL RECOMMENDATIONS

We based our geotechnical engineering analysis on the information developed from our subsurface exploration and soil laboratory testing, along with the project development plans, site plans, and structural loading furnished to our office. The following sections of the report provide our detailed recommendations.

6.1 Elevated Passenger Connector Foundations

Shallow foundations rely on the strength and compressibility properties of the underlying soil for support of a structure. Karst geologic formations inherently have an increased risk (compared to non-karst geology) for subsidence or settlement of shallow foundations due to the nature of carbonate rock. The site’s history of sinkholes, the existing Terminal Building foundation modifications during construction, and conditions encountered in the test borings confirm the unpredictability and high-risk nature of the site’s geology that is not conducive to shallow foundations. The proposed elevated passenger connector column foundations are in close proximity to the proposed garage elevator foundation, active arrival/departure lanes, existing Terminals 3, 4, and 5 buttress foundations, and underlain by highly variable soil/rock conditions. Additionally, the proposed foundations are proposed at varying grades: at the garage elevator lobby grade, at the departure lane (top of embankment) and in the middle of the embankment slope and the elevator near the arrival lane grade (bottom of embankment). Shallow foundations would likely result in high bearing pressures with total and differential settlements exceeding tolerable limits. Furthermore, the proposed foundations are subject to net-uplift loads of 10 to 70 kips per column; shallow foundations would not provide adequate resistance to uplift loads. For these reasons, we do not recommend shallow foundations.

Deep foundations may consist of driven piles or various drilled foundation types. Driven piling is problematic in karst due to the highly variable bedrock surface that can result in long pile lengths and piles out of plumb or position tolerance from the pile’s inability to be seated into sloping bedrock. Short pile lengths can result in very low uplift capacities. Driven piles can also refuse on boulders or pinnacled rock ledges in karst that can result in a reduced capacity of the bearing layer should these features yield.

Driven piling also involves noise and vibration during construction, which could impact adjacent structures and facilities.

Drilled foundations may be either large or small in diameter. Large diameter drilled foundations (e.g., drilled shafts) have disadvantages over small diameter drilled foundations (e.g., micropiles) at this site because they require large installation equipment, are less flexible with element placement, and can be problematic during installation in karst geology. Large drilled elements can have issues “biting” into sloping bedrock due to their diameter. Large elements are also less conducive to flexibility in element placement, and the various space constraints at this site can be restrictive; therefore, we recommend a small diameter drilled foundation (micropiles) for this project.

Micropiles are a drilled, deep foundation consisting of a steel casing, cement grout, and reinforcing bar(s).

Rock-socketed micropiles are recommended for this site, where the casing extends through the overburden soil to the rock socket. The rock socket consists of a reinforcing bar and cement grout that bond to the rock, giving the micropile axial capacity in compression and tension. Micropiles that are

February 16, 2026 Page 9 Schnabel Engineering, LLC designed to be socketed into rock and are installed properly can achieve low settlement tolerances and greatly reduce the risk of settlement of the structure due to karst activity.

An advantage of using micropiles in karst conditions is that the pile can be advanced through voids, soil-filled voids, and/or broken rock conditions to a competent rock layer. Foundations drilled into rock can be monitored during installation to ensure they are socketed into competent bedrock, as opposed to a driven pile foundation where competent bearing rock beneath the tip elevation cannot be verified. As a small diameter drilled foundation, micropiles are capable of “biting” into sloping bedrock more easily than a large diameter drilled foundation. Furthermore, the small diameter foundation equipment is advantageous when working around the tight site constraints (utilities, adjacent parking areas, etc.) because the micropile equipment has more flexibility and requires less lay-down areas for equipment and material staging compared to larger foundation equipment. Micropile installation equipment can also be used to perform LMG operations to remediate sinkholes or fill encountered voids. An LMG sinkhole remediation was performed during micropile installation for the LVIA Terminal-Connector project, with minimal downtime in transitioning between micropile installation and LMG operations. Micropiles are also recommended and being designed for the adjacent proposed parking garage structure foundations.

6.1.1 Micropile Design

TLC provided allowable-stress design (ASD) loads at column/elevator foundations for the proposed elevated passenger connector. Axial, lateral, uplift, and moment allowable loads at the elevated passenger connector columns ranged from 40 to 130 kips, 10 to 22 kips, 10 to 70 kips, and 115 to 150 kip-ft per column, respectively. TLC also indicated tolerable deflections of 0.5 inch for both vertical and lateral loads. Micropiles perform well when subjected to axial and lateral loads. As slender elements, they generally cannot resist high lateral loads as single vertical elements; however, when battered and used in groups, they can be designed to resist lateral loading more efficiently. Conceptual allowable axial capacity and associated bond length are presented below. Based on the lateral loads, battered micropiles are anticipated at the elevator tower foundation.

Table 6.1: Conceptual Micropile Allowable Axial Capacities and Bond Length

Micropile Diameter (inches)

Bond Length in Rock

(ft)

Allowable Axial Capacity

(kips) 7 5–8 60–150

Note: Capacities are for conceptual design purposes only. Details such as casing thickness, reinforcement size, etc. are not specified herein.

Refer to design submissions for more details.

We understand the loads will be refined as the design process continues. Conceptual calculations were performed using the Micropile Design and Construction Reference Manual (FHWA NHI-05-039) and IBC 2021. Table 6.1 shows conceptual micropile allowable stress design capacities. The capacities are based on an ultimate grout-to-rock bond stress of 150 psi. This bond stress should be confirmed during construction as part of a load testing program. Details of the load testing program will be outlined in the micropile drawings and specifications.

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6.1.2 Existing Terminal Building Footings

The existing terminal building is supported on three foundation types: Type A and C foundations are spread footings on rock with a design bearing pressure of 15 ksf; Type Aꞌ and Cꞌ foundations are spread footings bearing on soil with a 2.5 ksf bearing pressure; and Type B foundations are supported on HP10 piles driven to refusal on bedrock.

The existing spread footings at Columns 4B and 5B are Type C and A foundations (spread footings on rock), respectively, and both footings have dimensions of 6 ft by 6 ft. TLC indicated the elevated pedestrian connector will increase the loads on these foundations as shown in Table 6.2.

Table 6.2: Existing Spread Footings Loading

Spread Footing Existing

Load (kips)

Existing Bearing Pressure

(ksf)

Existing Footing Allowable Bearing Pressure

(ksf)

Proposed Additional

Load (kips)

Proposed Footing Bearing Pressure

(ksf) Column Line 4B (Type C Footing) 300 8.1 15 40 9.2

Column Line 5B (Type A Footing) 300 8.1 15 20 8.7

The bearing pressure of the existing columns with the additional load from the elevated passenger connector is roughly 9.2 and 8.7 ksf at Column Lines 4B and 5B, respectively. These values are less than the allowable bearing pressure of 15 ksf noted on the as-built drawing set. The proposed bearing pressure results in less than ⅔ of the existing footing allowable bearing pressure of 15 ksf. We recommend that TLC consider the increased loads on the existing structure (columns, footings, etc.) as part of the structural design.

6.2 Contractor-Designed Items

We recommend that the proposed construction include Contractor-designed items, including temporary excavation support for the proposed elevator tower and foundation. The design and installation of Contractor-designed items should be signed and sealed by a licensed Professional Engineer in the Commonwealth of Pennsylvania and performed by a specialty Contractor who has experience in the construction of this particular type of work.

6.3 Temporary Excavation Support

We expect the proposed elevator pit excavation will require temporary excavation support due to the proximity of adjacent and active terminal buildings and departures roadway. Selection and design of the excavation support system are the responsibility of the Contractor.

We anticipate a soldier pile or micropile and wood lagging system will be appropriate excavation support for this project. Soldier piles should be inserted into predrilled holes; micropiles can be drilled in-place.

The predrilled soldier beam holes should be backfilled with lean concrete. Wood lagging should have an unfinished thickness of at least 3 inches. Proposed pile caps with vertical micropiles are located behind the temporary excavation support, such that temporary excavation support anchors need to be coordinated with proposed connector micropile foundations. We do not recommend a soil nail wall for temporary excavation support because soil nail walls require more anchors than soldier pile or micropile

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Tiebacks may be used to resist horizontal loads acting on the excavation support system. Tiebacks should be located to avoid buried structures, the existing tunnel structure, and proposed permanent foundations.

Lateral loads for excavation support design will be developed by the Contractor and must consider sloping retained earth, surcharge, and construction loads. Where tiebacks are used, each tieback must be tested. A detailed specification should be prepared for the installation and testing of earth tiebacks.

Design and installation should be performed in accordance with the Post Tensioning Institute’s Soil and Rock Anchors (2014). Specifications should require that performance tests be done at the beginning of the project on at least one tieback installed to demonstrate the suitability of the tieback design.

Additionally, at least 5% of the tiebacks installed on the project should be performance tested.

All production tiebacks should be proof tested. Proof testing should be performed as described above for performance testing, except the maximum load for a proof test is 120% of design load. We recommend the Geotechnical Engineer be engaged for observation of installation and testing of the tiebacks.

Excavation support elements consisting of soldier piles/micropiles and lagging is a flexible system.

Therefore, vertical and lateral movements beyond the limits of the excavation may cause damage to the adjacent roadways, canopies, sidewalks, or utilities. Criteria for allowable deflections of the system should be developed by the Owner and Structural Engineer, and the lateral and vertical movements of the excavation bracing system should be monitored. Adjacent buildings and ground surface should also be monitored for movement. Excavation subgrades should be monitored for instability both during excavation and following completion of the excavation.

The Contractor may incorporate temporary slopes for the excavation of garage foundations during construction. Temporary cut slopes on the site should satisfy OSHA requirements.

6.4 Elevator Walls

We understand permanent proposed below grade elevator walls will be braced by the structure to support the embankment and prevent movement. The elevator structure walls should be designed considering equivalent fluid pressure, gef (Table 6.3). Where applicable, the design should consider surcharge loads using a rectangular earth pressure distribution. The surcharge pressure ordinate should be obtained by multiplying the surface surcharge pressure, q, by the surcharge pressure factor in Table 6.3.

Table 6.3: Recommended Design Parameters for Walls – At-Rest

Backfill Materials Equivalent At-Rest

Fluid Pressure Factor (gef)

Surcharge Pressure Factor

On site (CL) 65.0H 0.55

The above parameters consider a horizontal ground surface behind the walls.

These design parameters do not consider hydrostatic pressure. Although groundwater levels are below the proposed elevator foundation grade, subdrainage should be provided behind the elevator walls.

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Subdrainage should consist of perimeter subdrains located on top of the wall footing next to the wall.

Elevator walls should be damp proofed.

For walls designed considering that on-site materials be used for backfill, backfill should consist of material classifying as CL, ML, SC, and GC according to ASTM D2487.

The Contractor should place backfill in maximum 8 inch thick loose lifts and compact each lift to at least 95% of maximum dry density according to ASTM D698 (Standard Proctor). Only light, hand-operated equipment should be used to compact backfill against walls. The Structural Engineer of Record should approve the size of the compaction equipment.

6.5 Construction Sequencing

Temporary excavation support, including vertical elements and/or anchors, should be completed (installation, tensioning, and lock-off) prior to installation of permanent micropiles. Installation of temporary excavation support anchors and/or tensioning of temporary excavation support anchors after installation of permanent micropiles will not be permitted.

6.6 Instrumentation and Monitoring

We recommend that the project include instrumentation and monitoring of existing terminal buttress foundations, existing terminal structure, arrival/departure roadway structures, temporary excavation support, and proposed foundations during construction. Use of an automatic total station (AMTS) with prism-targets mounted to existing features would provide real-time data during construction. Monitoring should be installed and baseline readings completed prior to the start of temporary excavation work and foundation construction. Instrumentation and monitoring details are included in the Temporary Excavation Support specification.

7.0 CONSTRUCTION CONSIDERATIONS

7.1 Site Grading and Earthwork

The proposed connector grading indicates that the site grades are similar to existing grades.

Recommendations for compacted fill, subgrade preparation, fill soil requirements, placement and compaction criteria, monitoring fill settlement, and evaluating rock excavation are presented in subsequent sections.

7.2 Compacted Fill

Compacted structural fill should consist of non-organic on-site soils classifying as CL, ML, SC, SM, SW, GC, and/or GM. If off-site borrow materials are needed, these soils should classify as SC, SM, SW, GC, or GM according to ASTM D2487. Fill materials should not contain particles larger than 3 inches. In addition, off-site fill materials should exhibit Liquid Limit and Plasticity Index values of less than 45 and 20, respectively.

Any compacted structural fill should be placed in maximum 8 inch thick horizontal loose lifts. Fill should be compacted to at least 95% of the maximum dry density per ASTM D698 (Standard Proctor).

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Backfill in excavations, trenches, and other areas that large compaction equipment cannot access should be placed in maximum 6 inch thick lifts. Backfill should meet the material, placement, and compaction requirements outlined above.

Successful reuse of the excavated, on-site soils as compacted structural fill will depend on their natural moisture contents during excavation. Based on laboratory test results, we expect the on-site soils in areas that will be excavated are generally wet of the optimum moisture content. Scarifying and drying of these soils should be anticipated to achieve the recommended compaction. Drying of these soils will likely result in some delays. This could be difficult without sufficient open areas and may not be possible during cooler, wetter weather. We recommend that the earthwork be performed during the warmer, drier times of the year.

7.2.1 Rock Excavation

The test boring data, when compared to proposed foundation grades, indicate that rock may be encountered during foundation excavation at the elevator structure. Conditions encountered during excavation may be different from those observed in the test boring data; therefore, we recommend the contract documents include unit prices for rock excavation. Table 7.1 provides elevations where shallow top of rock was observed and excavation methods, such as hoe-ramming, could be required. Blasting is not recommended due to existing adjacent terminal structure(s).

Table 7.1: Estimated Top of Rock Elevations

Boring Number Top of Rock Elevation (ft)

BB-1 360.5

BB-2 353.0

BB-5 359.5

Variations in rock conditions should be expected because the rock surface can fluctuate across the site due to karst geology. Also, the extent of rock excavation will depend on the Contractor’s methods, rock jointing, and rock foliation. The elevations noted above apply to mass excavation of rock on the site. Rock excavation methods may be needed at higher elevations in footing and utility excavations.

A sample definition of rock for excavation specifications is provided below:

For mass excavation, rock is defined as any material that cannot be dislodged by a Caterpillar Model No. D-8 heavy-duty tractor, or equivalent, equipped with a hydraulically operated, single-tooth power ripper without the use of hoe-ramming or blasting. For trench, footing and pit excavations, rock excavation shall be defined in terms of a Caterpillar Model No. 330 hydraulic excavator, or equivalent. This classification does not include material such as loose rock, concrete, cemented gravel, or other materials that can be removed by means other than hoe-ramming or blasting, but which for reasons of economy in excavating, the Contractor chooses to remove by hoe-ramming or blasting. Rock does not include boulders less than one cubic yard in volume. Boulders larger than one cubic yard in volume will be considered rock for payment purposes.

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Where the rock cannot be removed with conventional excavation equipment, special means of excavation may be needed. Removal of rock may require the use of blasting, air-powered tools, rock splitters, or large hoe rams.

The excavation contract may be bid on either an unclassified or classified basis. With unclassified excavation, there is no distinction between soil and rock. The Contractor is responsible for reaching design grades regardless of the material type encountered. With classified excavation, the Contractor would be paid a separate unit price for excavated rock and a separate price for excavated soil. The Contractor’s bid price for an unclassified excavation contract will normally be greater than the price for a classified contract; however, the potential for extras due to rock excavation will be significantly greater with the classified contract.

7.3 Micropile Installation Observation by Foundation Designer (Schnabel)

Micropiles are a practical choice for this project and geology; however, they are a foundation type that requires foundation engineering expertise from design through construction to optimize their use and control costs. Micropiles are typically recommended by the Geotechnical Engineer and designed by the Structural Engineer as they complete the foundation layout and pile cap designs. Furthermore, many times there is a third-party construction inspection firm overseeing their installation. This leads to conservatism from all parties, as neither the Geotechnical Engineer nor the Structural Engineer has a full understanding of both the ground conditions and building needs, and the construction inspector does not fully understand the design intent. This conservatism gets amplified when the site has difficult ground conditions such as the karst at this site, as a perception of greater risk drives more caution in the design expressed as a higher design factor of safety, more redundancy through an increased number of piles, and conservatism in the installed micropile bond length.

These factors in karstic terrain lead to installation of long, relatively lightly loaded micropiles extending through encountered and possible voids, weathered rock, and fractured rock. Where open voids, soil-filled voids, and fractures are encountered, grout loss often occurs; this is often resolved by the specialty contractor pumping dramatic volumes of high mobility micropile grout in an attempt to fill the hole.

Additionally, fractures and soil seams throughout the rock strata are often disregarded, and the bond zone is started below the fractures and soil seams to get “good rock.” These practices can lead to excessively long piles, an excessive number of piles, high quantities of cement use, larger than necessary pile caps, increased potential for pile conflicts, and unnecessary delays and cost to the owner.

Micropile designs and construction observation are most efficiently performed by a Foundation Engineer who understands the ground conditions, how micropiles are constructed, how they perform, and the demands of the structure. Only when the Foundation Engineer understands the entire project and has influence during construction, including quality control and treatment of anomalies encountered, are the risks of construction in difficult ground mitigated. When the Foundation Engineer is involved from subsurface investigation through construction of the micropiles, real cost savings can be realized.

Schnabel has the expertise as a Foundation Engineer to efficiently design and oversee the construction of micropiles in difficult ground conditions. Schnabel is designing the micropile foundations for the project and is designing with the assumption that we will observe micropile installation during construction in order to confirm design assumptions and maximize…