B08_Attach_4_CONG_-_Pavement_Investigation___Analysis_Report.pdf

National Park Service U.S. Department of the Interior

PAVEMENT INVESTIGATION AND ANALYSIS REPORT

Congaree National Park (CONG) NPS Contract No. 140P2022D0002 NPS Task Order No. 140P2025F0167

PMIS 334914

July 28, 2025

Table of Contents

1.0 Project Description

2.0 Scope of Work – Predesign (PD) Phase

2.1 Review of RIP Data

2.2 Review of FY19 Pavement Preservation Design Scoping Report for CONG

2.3 On-Site Scoping and 70% Design Site Visit

3.0 Scope of Work – Design Development (DD) Phase

3.1 70% Design Site Visit

3.2 Subsurface Sampling and Investigation

3.3 Review of Available Traffic Data

3.4 Construction Summary Estimate

3.5 Construction Schedule Summary

4.0 Pavement Analysis, Findings, and Recommendations

Appendix A – Project Location

Appendix B – Scoping Site Visit Field Notes and Photos

Appendix C1 – Subsurface Sampling and Geotechnical Test Data

Appendix C2 – Material Sampling Photo Documentation Log

Appendix C3 – Laboratory Test Results of Unbound Materials

Appendix D – Traffic Data for Pavement Design

Appendix E – AASHTO 1993 Pavement Design Calculations

Appendix F – Construction Cost Estimate Summary

Appendix G – Construction Schedule Summary

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1.0 Project Description

National Park System (NPS) retained AECOM Services, Inc. (AECOM) to provide engineering services related to pavement preservation at multiple parks in South Carolina. Preservation is the strategy designed to maintain and restore the overall condition of relatively new pavements that are in good to fair condition (distress severity and extent are low/moderate) by protecting them from water intrusion and limiting oxidation using treatments such as crack seal, slurry seal, chip seal, micro surfacing, and thin overlays. Pavement preservation treatments generally can extend the life of pavement in good or fair condition by 5-7 years and delay more expensive and intrusive rehabilitation activities.

As outlined in the project Scope of Services, the goal is to evaluate selected paved roads and parking areas at the Congaree National Park (CONG) and identify suitable pavement preservation or rehabilitation treatments. AECOM conducted pre-design activities, including an on-site scoping site visit and review of available project documents, to perform an initial pavement assessment.

The preliminary findings were documented in a Pavement Analysis Report dated February 22, 2025.

This report supplements the February 2025 pavement analysis by incorporating findings from additional pavement investigations and analyses conducted by AECOM during the Design Development (DD) phase. It presents the final recommendations for pavement treatment options for the designated roads and parking areas at CONG, in accordance with Chapter 11 of the Federal Highway Administration (FHWA) Project Design and Development Manual.

To ensure continuity and completeness in documenting the pavement evaluation efforts and findings, the activities conducted during the predesign (PD) phase are discussed in Section 2 of this report, while the DD phase activities are documented in Section 3. Section 4 contains the findings and recommendations. The specific roadway and parking lot sections are listed in Table 1, and the project location is provided in Appendix A.

2.0 Scope of Work – Predesign (PD) Phase

AECOM performed the following activities at CONG during the predesign phase:

2.1 Review of RIP Data

NPS provided AECOM with the Federal Highway Administration’s (FHWA) Road Inventory Program (RIP) report for CONG (Cycle 6 Final Report – Road Inventory and Condition Assessment of Paved Road, November 2021). AECOM reviewed the RIP report to obtain the roadway inventory and existing condition information for the target road and parking lot sections of CONG; i.e., sections identified by the RIP report as candidates for pavement preservation as well as sections adjacent to candidate section(s) and/or sections deemed to be in similar condition to candidate section(s).

Table 1 summarizes the relevant RIP data for the candidate/added section of CONG. The added sections (shown in blue text throughout the report) are included in the 70% design plans as “Options”.

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Table 1: CONG Target Road/Parking Lot Sections RIP Data

ROUTE ID ROAD

AREA

(SF)

LENGTH

(MILES)

ROADWAY

WIDTH (FT)

PAVEMENT

TYPE

PCR

RECOMMENDED

TREATMENT

CONG-0010 ENTRANCE ROAD 1.25 22 Asphalt 100 Localized Repair CONG-0100 LONGLEAF CAMPGROUND ACCESS RD 0.02 13 Asphalt 98 Localized Repair CONG-0900 VISITOR CENTER FIRST PARKING 13,648 Asphalt 97 Localized Repair CONG-0901 VISITOR CENTER BUS PARKING 16,499 Asphalt 97 Localized Repair CONG-0902 EMPLOYEE PARKING 5,804 Asphalt 97 Localized Repair CONG-0909 VISITOR CENTER MIDDLE PARKING 14,462 Asphalt 97 Localized Repair Notes:

1) PCR = Pavement Condition Rating, L3R = Light Rehabilitation, H3R = Heavy Rehabilitation

2) Throughout this report, Added Sections are shown in BLUE.

2.2 Review of FY19 Pavement Preservation Design Scoping Report for CONG

NPS provided AECOM with the Design Scoping Report for the previous round of pavement preservation project for CONG (NP-SER PMS FY19). A review of this report indicated that all CONG target sections were also considered for pavement preservation treatments as part of the FY19 project. Further discussions with the NPS team and the Park Units and a review of other relevant project documents confirmed that these sections received pavement preservation as part of the SER PMS FY19 Project. The available project plans included four proposed preservation treatment options, namely, 1.5 in. overlay, 0.75 in. overlay, chip seal, and micro-surfacing, however, the actual treatment selection for each road/parking lot section was left up to the contractors. AECOM’s visual observations regarding the most likely past pavement preservation treatment are included in Table 3.

2.3 On-Site Scoping and 70% Design Site Visit

AECOM performed an on-site scoping field visit on November 26, 2024, along with members of the NPS project team and the CONG Park Unit team. Per the project scope, the on-site scoping field visit was conducted to evaluate the current site conditions of the park sections listed in Table 1. The project team’s on-site scoping field visit activities included the following:

• Conduct tailgate safety briefings with the project team and sign Task Hazard Assessment

(THA).

• Discuss the scope and objectives of the on-site field visits with the Park Unit Team.

• Gather site-specific information from the Park Unit Team including:

- Priorities of roadways to treat,

- Other ongoing/planned projects that may impact the planned pavement treatment work,

- Concerns with existing roadway configurations (one-way roads),

- Any present or anticipated changes in vehicular traffic volume and/or type within the park.

- Past safety incidents/concerns related to roadway signage reported by park users,

- Past pavement preservation/rehabilitation work at the park and experiences with those treatments,

- Any other relevant information such as staging areas, permitting requirements, etc.

• Conducting the site walk of each roadway/parking lot section to:

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- Evaluate the existing pavement condition, including estimating cracks and identifying the preliminary pavement preservation treatment.

- Evaluate the conditions of existing curbs, gutters, wheel stops, drainage inlets, ADA ramps, etc., and note improvement requirements.

- Provide opinion on the condition and adequacy of existing roadway and parking signage, including handicap parking signs.

- Review the existing striping (including the need for scarifying thermoplastic prior to treatments) and the need for striping parking stalls, as well as add/relocate handicap parking spots.

The draft on-site scoping field meeting minutes were submitted to NPS on December 15, 2024, and the final meeting minutes (revised per NPS comments) were submitted to NPS on January 17, 2025.

The field notes from the on-site scoping field meeting including geo-referenced photographs taken by the project team are included in Appendix B.

3.0 Scope of Work – Design Development (DD) Phase

AECOM performed the following activities during the DD phase to finalize the pavement preservation treatment recommendations for the CONG sections:

3.1 70% Design Site Visit

AECOM conducted a 70% design site walk at the Park on May 31, 2025, to supplement the findings from the scoping site walk and perform a more detailed pavement condition survey. This was to finalize pavement recommendations and the 70% design deliverables. The following activities were conducted during the 70% design site walk:

• Establish the project baseline for the 70% design plans.

• Identify the locations and conditions of the existing roadway features, such as structures (bridges and culverts), signage, utility features, traffic loops, etc., and note improvement needs.

• Identify locations that require localized pavement treatments such as full or partial depth patching and aggregate/seed mixes for shoulder support.

The findings from the 70% design site walk along with corresponding recommendations, are incorporated into Section 4 of this report and the 70% design plans.

3.2 Subsurface Sampling and Investigation

Due to the observed load-related cracking and poor cross-slope at the Visitor Center Bus Parking (CONG-0901), subsurface investigation was conducted to obtain detailed pavement structure information—such as layer types, thicknesses, and engineering properties of both bound and unbound layers—to support the final treatment recommendations. On 05/31/2025, AECOM extracted four (4) pavement cores and two (2) test pits from CONG-0901 and an additional two (2) cores from the Entrance Road (CONG-0010). The Geotechnical test results are included in Appendices C1 through C3, and the key findings are discussed below:

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• Visitor Center Bus Parking (CONG-0901) o Asphalt within CONG-0901 is 5 to 8.5 inches with an average of approximately 7 inches.

o Debonding of the surface course was observed in two of the four cores and in one of the two test pits.

o The soil samples extracted from the test pit locations indicated the presence of 5.5-

10.5 inches of base quality material. A 6-inch-thick aggregate base is assumed for pavement design purposes.

o The subgrade was found to contain mostly clayey sand (AASHTO classification A-7-6 or A-6 / USCS class SC). A design subgrade resilient modulus (MR) value of 7,000 psi is assumed for pavement design purposes.

• Entrance Road (CONG-0010) o Asphalt thickness along CONG-0010 varies from 5 to 5.5 inches.

o One of the two cores exhibited debonding of the surface course.

o A crushed aggregate base exists beneath the asphalt layer. Since no test pits were available to determine the base thickness, a 6-inch aggregate base layer is assumed below the asphalt, similar to the CONG-0901 pavement.

3.3 Review of Available Traffic Data

AECOM downloaded and reviewed the historical traffic counts for the Entrance Road (CONG-0010) from the “NPS Stats Report Viewer” website. An average daily traffic (ADT) of 206 was reported for 2024, while for the current year (2025), the reported ADT through June is 262. Considering the historical traffic volume counts (from 2021 to 2024), a design ADT of 250 is deemed appropriate for this road. Using this, along with an assumed 1% bus traffic, an 18-kip equivalent single axle load (ESAL) of 23,442 is calculated for CONG-0010 for a 20-year design life. For CONG-0901, it is conservatively assumed that approximately half of the park’s total vehicular traffic will use this parking lot, thereby resulting in a 20-year design ESAL of 11,721. The reviewed traffic data and the ESAL calculations are included in Appendix D.

3.4 Construction Summary Estimate

A DD-Phase construction cost estimate, aligned with the Department of the Interior (DOI) Estimate Type B, is being prepared based on the proposed pavement treatments for the parking lots and roadway sections of CONG. This estimate will be submitted as a separate deliverable with the 70% design package. A summary of the estimated construction cost, based on a DOI Estimate Type C for CONG, is included in Appendix F.

3.5 Construction Schedule Summary

A construction schedule was developed based on the pavement preservation treatments proposed for the parking lots and roadway sections of CONG, and it is included in Appendix G.

4.0 Pavement Analysis, Findings, and Recommendations

AECOM performed pavement design analysis to determine the structural adequacy of CONG-0901 and CONG-0010 to support the expected design traffic load for a 20-year service life. The remaining

PAVEMENT INVESTIGATION AND ANALYSIS REPORT 7 | P a g e sections of CONG exhibit limited pavement surface distress and are hence considered ideal for pavement preservation treatments. Pavement design calculations were performed according to the AASHTO Guide for Design of Pavement Structures, 1993, and in line with Chapter 11 of the FHWA Project Design and Development Manual. The AASHTO 1993 design calculations are included in Appendix E, and the findings and recommendations are discussed below:

Visitor Center Bus Parking (CONG-0901)

The pavement exhibits signs of load-related cracking and poor cross-slope through the middle of the parking lot, causing water ponding. Based on AASHTO 1993 design calculations, the existing pavement structure—consisting of ~7 inches of asphalt over a 6-inch aggregate base with a subgrade MR of 7,000 psi—is structurally adequate to support the design traffic loading. An asphalt mill and overlay treatment is recommended for this parking lot to correct the pavement slope, combined with localized patches to correct tree root damage. A 3-inch mill depth is deemed appropriate, as this will remove the debonding issues observed in the surface layer.

Entrance Road (CONG-0010)

Based on AASHTO 1993 design calculations, the existing pavement structure—consisting of ~5inches of asphalt over a 6-inch aggregate base with a subgrade MR of 7,000 psi—is structurally adequate to support the design traffic loading. Indeed, a majority of the pavement is in good condition, with areas of low severity Alligator Cracking or minor tree root damage. Thus, localized patching followed by surface treatment via crack sealing and seal coating is recommended for this road. Additionally, leveling via mill and overlay is recommended to correct a Depression next to an existing culvert near ~MP 0.25.

Longleaf Campground Access Road (CONG-0100)

The existing pavement has minor damage from tree roots. The intersection of CONG-0100 with the campground gravel parking lot (CONG-0906) exhibits gravel loss. It is recommended to saw-cut the end of the paved roadway and add new aggregate (place, compact, and grade) at this location. The remaining roadway pavement is recommended for preservation through crack sealing and seal coating.

Visitor Center First & Middle Parking (CONG -0900 & CONG -0909)

The pavement is in good condition, with some Edge Cracking and low-severity Longitudinal and Transverse Cracking due to tree root damage. Pavement preservation with crack sealing followed by seal coating is proposed for this parking lot.

Employee Parking (CONG-0902)

This parking lot is currently not in the project scope; however, it was part of the SER-PMS-FY19 Project, and the pavement condition is similar to that of the adjacent VC parking lots, hence is being included in the 60% design plans as an “Option”. This roadway is proposed for the same treatment as CONG-0900 and CONG-0909 (crack seal and seal coat).

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The following additional design considerations apply to CONG:

• Isolated areas needing more extensive repairs, such as partial- or full-depth patches due to significant damage like high-severity alligator cracks, edge cracks, or potholes, are identified during AECOM’s 70% design site visit and shown in the 70% design plans.

• Aggregate/seed mixes are recommended to fix edge-shoulder drop-off in specific areas along CONG-0010 and CONG-0100. The locations and quantities of these mixes are detailed in the 70% design plans.

• Signage improvements are recommended, including new pedestrian crossing signs and pavement markings along CONG-0010

• Revising structural grading is not a part of this pavement preservation project but the observed adverse drainage conditions (water ponding issues, failed/deteriorated drainage structures, etc.) were noted during the site scoping field visit. Minor grade corrections will be achieved via asphalt mill and overlay treatments, where such treatments are recommended. The table below includes the drainage condition observations for each CONG section:

Table 2: Drainage Observations for CONG Sections Route ID Drainage Observation CONG-0010 RCP pipe culverts in fair to good conditions CONG-0100 None CONG-0900 None CONG-0901 Drainage swale in fair condition (needs cleaning) CONG-0902 None CONG-0909 None

Below is a summary of the findings and recommendations for each park section based on the pavement investigation and analysis findings:

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Table 3: Findings and Recommendations for Each CONG Road/Parking Lot Section

Route ID Previous Preservation

Treatment (FY19)1

From the RIP Report From AECOM’s Field Scoping Site Visit Comment / Reasons for Variance PCR

Recommended Treatment2

Overall Pavement

Condition Predominant

Distress Treatment

Recommendation

CONG-0010 1.5” Overlay 100 Localized

Repair Good Alligator cracking, depression edge cracking, edge drop-off

Crack seal & seal coat w/ localized patching

CONG-0100 1.5” Overlay 98 Localized

Repair Good L&T cracking (tree root) Crack seal & seal coat

CONG-0900 1.5” Overlay 97 Localized

Repair Good

L&T cracking (tree root) edge cracking, edge drop-off

Crack seal & seal coat

CONG-0901 1.5” Overlay 97 Localized

Repair Fair

Depression, block cracking, L&T cracking (tree root)

3” AC mill & overlay w/ localized patching

Pavement condition is considerably worse than the RIP reported

CONG-0902 1.5” Overlay 97 Localized Repair

Good L&T cracking (tree root) Crack seal & seal coat w/ localized patching

CONG-0909 1.5” Overlay 97 Localized

Repair Good Edge cracking Crack seal & seal coat

Notes:

1) The most likely previous pavement preservation treatment based on the visual observations during the on-site scoping site visit.

2) Per the RIP Report, below are the descriptions of the recommended treatment categories:

a. Localized Repair: Pavement in “Excellent” condition (PCR = 95-100). Treatment includes spot repairs.

b. Preventative Maintenance: Pavement in “Good” condition (PCR = 85-95). Treatments include crack sealing, chip seal, slurry seal, micro-surfacing, thin/ ultrathin overlay, concrete joint sealing, diamond grinding, dowel-bar retrofit, and isolated, partial or full-depth concrete slab repairs.

c. Light Rehabilitation: Pavement in “Fair” condition (PCR = 60-85). Treatment includes single-lift overlay up to 2.5” and milling and overlaying.

d. Heavy Rehabilitation: Pavement in “Poor” condition (PCR < 60). Treatment includes multi-lift overlay > 2.5”.

e. Reconstruction: Pavement in “Poor” condition (PCR < 60). Treatment includes replacing the entire existing pavement structure.

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Note that the overall pavement conditions were rated as Good/Fair/Poor based on AECOM’s on-site scoping field visit observations. Standard pavement engineering practices were applied to determine such rating, a summary of which is included below for reference:

“Good” pavement condition:

• Pavement has minimal surface defects.

• No significant cracks, potholes, or raveling (loss of aggregate).

• Minimum aging (surface color remains dark, indicating minimal loss of asphalt binder due to oxidation).

• Maintenance treatments, e.g., seal coating, crack sealing, etc. are appropriate for a “Good” condition pavement.

“Fair” pavement condition

• Some visible signs of wear, such as minor cracks (hairline to ¼ inch wide).

• Early signs of aging (fading asphalt color).

• Some surface raveling or minor depressions but no major structural issues.

• Patching or previous repairs are intact.

• Heavier preservation treatments, such as localized repair, micro surfacing, or resurfacing are considered to treat a pavement in “Fair” condition.

“Poor” Condition

• Extensive cracking, including alligator (interconnected) cracks or wide transverse/longitudinal cracks (>¼ inch).

• Potholes, ruts, or significant depressions present, causing uneven surfaces.

• Medium to severe raveling or aggregate loss, leading to rough texture.

• Potential water pooling or drainage issues.

• Previous patches or repairs are deteriorating or failing.

• The pavement may be a candidate for a mill and overlay treatment or full-depth reconstruction.

Depending on the treatment types, pavement preservation activities generally can extend the life of a pavement by 5-10 years. For reference, the table below provides a general guideline on the expected performances of the different preservation treatments (when applied to a pavement in appropriate condition):

Table 4: “Expected” Performance Period of Typical Pavement Preservation Treatments Treatment Expected Performance (Years) Crack Sealing + Seal Coating (Slurry Seal) 5-7 Crack Sealing + Rejuvenating 5-7 Microsurfacing 6-8 Thin Overlay 8-10 Non-structural Mill and Overlay 10+

Appendix A – Project Location

PAVEMENT INVESTIGATION AND ANALYSIS REPORT Appendix A

CONG

PAVEMENT INVESTIGATION AND ANALYSIS REPORT Appendix A

Appendix B – Scoping Site Visit Field Notes and Photos

PAVEMENT INVESTIGATION AND ANALYSIS REPORT Appendix B

CONG-0010: Entrance Road Section Length/Area 1.25 Miles Other Observations Two plastic speed bumps (Fair to Poor) Pavement Type Asphalt Curb None RIP Data (PCR) 100 Sidewalk None Overall Pavement Condition Good Drainage Structure Several RCP pipe culverts1

Predominant Distress Alligator cracking, depression Edge cracking and edge drop off Road Signs Recommend adding pedestrian crosswalk signs

Recommended Treatment Asphalt patching with Crack seal & rejuvenator

Handicap Parking None

Geotechnical Testing None Existing Striping Thermoplastic STOP bar & DYCL (Fair) Notes:

1. Locations on the marked plan.

Section Distress Treatment

L/M Alligator Cracking 1,200 SF L Edge Cracking 100’ M Depression 200 SF

Asphalt patching with Crack seal & rejuvenator

Legend:

L, M – Low or Medium severity cracks DYCL – Double Yellow Center Line

30 Oblong RCP Pipe culvert

L/M Depression north of the existing culvert -Leveling or AC M&O

80 of Edge Cracking

- Asphalt edge repair

- Cut & lower embankment soil

24 White Stop Bar (Thermoplastic)

Inbound & Outbound pull-offs Shoulder/edge support needed (extend existing aggregate fill)

Loop (inbound)

High-tension overhead Power lines

Overhead Power lines

Tree root damage

- Patch (4 x 6 )

18 HTP/RCP Pipe culvert

6 + Edge drop south of this location

30 Oblong RCP Pipe culvert

Medium Alligator

- Patch (4 x 6 )

Underground fiber & electric lines ~20 from EOP throughout the length of the roadway

Medium Alligator

- Patch (100 x 6 ) (inbound lane)

Ped. -ingw. double-speed bumps on either side

(road signs in good condition)

Double Oblong RCP Pipe culvert

Medium Alligator

- Patch (10 x 6 )

Medium Alligator

- Patch (10 x 10 )

Medium Alligator

- Patch (20 x 20 )

Saw-cut & add aggregate the transition

24 White Stop Bar (Thermoplastic)

Ped. -ing

CONG-0010: Entrance Road

❶ Lat/Long: 33.830703,-80.822503 (MP 1.16) Medium Alligator Cracking

❷ Lat/Long: 33.831136,-80.825461 (MP 1.02) Low Alligator Cracking

❸ Lat/Long: 33.832325,-80.826347 (MP 0.93) Edge drop off, proposed location of seed-aggregate edge support

❹ Lat/Long: 33.839558,-80.828575 (MP 0.28) Edge Cracking. Cut and lower embankment soil

CONG-0100: Longleaf Campground Access Road Section Length/Area 0.02 Mile Other Observations Pavement Type Asphalt Curb None RIP Data (PCR) 98 Sidewalk None Overall Pavement Condition Good Drainage Structure None Predominant Distress L&T cracking (tree root damage) Road Signs Okay Recommended Treatment Crack seal & rejuvenator Handicap Parking None Geotechnical Testing None Existing Striping Thermoplastic STOP bar & DYCL (Fair) Notes:

Section Distress Treatment

1 L L&T (tree root) 5’ M L&T (tree root) 5’ Crack seal & rejuvenator

Legend:

L&T – Longitudinal & Transverse cracking

DYCL – Double Yellow Center Line

CONG-0100: Longleaf Campground Access Road

❶ Lat/Long: 33.836103,-80.828269 Pavement in good condition, thermoplastic double-yellow center line

(good condition).

❷ Lat/Long: 33.836089,-80.828231 Low-severity tree root damage.

❸ Lat/Long: 33.836106,-80.828247 Medium-severity tree root damage. Possible edge work to improve drainage

❹ Lat/Long: 33.836094,-80.828169 Edge of pavement in need of saw cut. Place new aggregate, compact, and grade.

CONG-0900: Visitor Center First Parking Section Length/Area 13,648 SF Other Observations Possible tree removals (by the Park) Pavement Type Asphalt Curb Rubber Wheel Stops at parking stalls (Good)

Wooden curbs (Poor - replace in kind)1 RIP Data (PCR) 97 Sidewalk Brick (Good) Overall Pavement Condition Good Drainage Structure None

Predominant Distress L&T cracking (tree root damage)1 Edge cracking1, edge drop off1 Road Signs Okay

Recommended Treatment Crack Seal & Seal Coat Handicap Parking Two (consider relocating)1 Geotechnical Testing None Existing Striping STOP Bar1: Thermoplastic paint (Fair)

Other striping: Regular paint (Fair/Poor)

L L&T 30’ L Edge Cracking 40’ Crack Seal & Seal Coat

L&T – Longitudinal & Transverse cracking

Seed-aggregate/ Edge support

Seed-aggregate/ Edge support

Wooden Curb (TYP) Fair - Replace in kind

30 L-L&T (tree root)

M-Edge Cracking (Patch)

24 White Stop Bar (Thermo-plastic)

2-handicap parking (no signs)

Safety concerns with existing handicapped parking location.

Consider moving here

Stop sign (wooden post)

Ped. -ing

Proposed tree removal by Park (Typ.)

CONG-0900: Visitor Center First Parking

❶ Lat/Long: 33.830528,-80.823364 L&T Cracking (tree root)

❷ Lat/Long: 33.830783,-80.823311 Edge Cracking (patch); proposed aggregate topsoil edge support.

❸ Lat/Long : 33.830514,-80.823333 Rubber wheel stops, wooden curb

❹ Lat/Long: 33.830161,-80.823447 Handicap parking – no signage, consider relocating

CONG-0901: Visitor Center Bus Parking Section Length/Area 16,499 SF Other Observations Possible tree removal (by the Park) Pavement Type Asphalt Curb Rubber Wheel Stops at parking stalls (Good) RIP Data (PCR) 97 Sidewalk Brick (Good) Overall Pavement Condition Fair Drainage Structure Drainage swale1 (needs cleaning)

Predominant Distress Depression, Block Cracking, tree root damage Road Signs Add signage for “Trailer Parking”

Recommended Treatment Patching, asphalt M&O Handicap Parking None Geotechnical Testing 6 cores and 2 test pits Existing Striping STOP Bar1: Thermoplastic paint (Fair)

Other striping: Regular paint (Fair)

M Depression 150 SF L Block Cracking 300 SF

Patching, asphalt M&O

M&O – Mill & Overlay

Depression with Load -related Longitudinal Cracking

Aggregate Top Soil (Park preference)

Water ponding

10 x 10 Patch for tree root damage

24 White Stop Bar (Thermo-plastic)

Stop sign (wooden post)

Standard Parking

Oversized Parking

Oversized Parking

Drainage swale

CONG-0901: Visitor Center Bus Parking

❶ Lat/Long: 33.830158,-80.823136 Depression with load-related cracking

❷ Lat/Long: 33.830331,-80.822525 Block Cracking/Reflective Cracking from underlying utility patch

❸ Lat/Long : 33.830331,-80.822264 Tree-root damage (Patch)

❹ Lat/Long: 33.830236,-80.822381 Depression with signs of water ponding (drainage path updated)

CONG-0902: Employee Parking (added) Section Length/Area 5,804 SF (6,334 SF) Other Observations Possible tree removal (by the Park) Pavement Type Asphalt Curb Rubber wheel stops (Good) RIP Data (PCR) 97 Sidewalk None Overall Pavement Condition Good Drainage Structure None Predominant Distress Tree root damage Road Signs Good Recommended Treatment Patching & Surface Treatment Handicap Parking None Geotechnical Testing None Existing Striping Regular paint (Good)

1 L/M Tree root damage Patching (20’ x 30’)

~200 SF

Potential 20 x 30 Patch to take care of tree root damage (Park preference)

Potential areas to pave over (Park preference) (check with compliance) removal by Park

CONG-0902: Employee Parking (added)

❶ Lat/Long:33.829761,-80.822669 Weathering, minimal pavement cracking

❷ Lat/Long: 33.829758,-80.8227 Weathering, minimal pavement cracking

❸ Lat/Long : 33.829931,-80.822617 Tree root damage

❹ Lat/Long: 33.829892,-80.822669 Low Edge Cracking/tree root damage

CONG-0909: Visitor Center Middle Parking Section Length/Area 14,462 SF Other Observations Possible tree removal (by the Park) Pavement Type Asphalt Curb Rubber Wheel Stops at parking stalls (Good)

Wooden curbs (Poor - replace in kind)1 RIP Data (PCR) 97 Sidewalk Brick (Good) Overall Pavement Condition Good Drainage Structure None Predominant Distress Edge cracking1 Road Signs Okay Recommended Treatment Surface Treatment Handicap Parking Two (consider relocating)1 Geotechnical Testing None Existing Striping STOP Bar1: Thermoplastic paint (Fair)

Other striping: Regular paint (Fair/Poor)

L Edge Cracking 40’ L L&T Cracking 50’ Crack Seal & Seal Coat

1-handicap parking

(no signs) 1-handicap parking (no signs)

Wooden Curb (TYP) Fair - Replace in kind

24 White Stop Bar (Thermo-plastic)

Edge Crack repair (40 )

Stop sign (wooden post)

Possible location of motorcycle parking

Proposed Ped. -ing

CONG-0909: Visitor Center Middle Parking

❶ Lat/Long: 33.830567,-80.822936 L&T Cracking (tree root damage)

❷ Lat/Long: 33.830742,-80.822778 Edge Cracking

❸ Lat/Long: 33.830606,-80.822806 Rubber wheel stops, wooden curb

❹ Lat/Long: 33.830158,-80.823128 Handicap parking (no signage)

Appendix C1 – Subsurface Sampling and Geotechnical Test Data

PAVEMENT INVESTIGATION AND ANALYSIS REPORT Appendix C

CONG Geotechnical Test Location

PAVEMENT INVESTIGATION AND ANALYSIS REPORT Appendix C

Table: Core Data Summary – CONG

AC Unbound Layers

Core/

TP #

Route ID Direction Thickness

(in) Cracking

(in.)

Debonding (in.) Base Subgrade Comment

C1 CONG-0901 -- 7.00 -- 1.875 Crushed Aggregate -- --

C2 CONG-0901 -- 5.13 -- -- Crushed Aggregate -- --

C3 CONG-0901 -- 8.00 -- 2.625 Crushed Aggregate -- --

C4 CONG-0901 -- 8.50 -- -- Crushed Aggregate -- --

C5 CONG-0010 NB 5.00 -- -- Crushed Aggregate -- --

C6 CONG-0010 NB 5.50 -- 1.875 Crushed Aggregate -- --

TP1 CONG-0901 -- 6.50 -- 2.00 10.5" of A-1-a 7.0" of A-7-6 Geofabric observed at 12" depth

TP2 CONG-0901 -- 7.00 -- -- 5.5" of A-1-a 7.5" of A-6 Geofabric observed at 11" depth

0.00

2.00

4.00

6.00

8.00

10.00

C1 C2 C3 C4 TP1 TP2

A C

T hi ck ne ss (i n.

CONG-0901 Asphalt Thickness

Appendix C2 – Material Sampling Photo Documentation Log

Date Site Code: CONG Sampled By JSG/NJ

Legend: G = Good F = Fair P = Poor

Sample Number: Dia.:

Location:

Thickness

G P G

Core Notes:

Sample Number: Dia.:

Location:

Thickness

G G

Core Notes:

Sample Number: Dia.:

Location:

Thickness

G P G

Core Notes:

Total Depth 8 inches

Bo nd

Q ua lit y

St rip pi ng

De te rio ra tio n

C3 6"

CONG-0901

Surface 2.125 HMA

Binder 2.375

Layer Type Description

H M A

Wearing Surface 0.5 HMA

Base 3 HMA

HMA

inches

Surface 1.5 HMA

Base 3.125 HMA

Layer Type Description

H M A

Wearing Course 0.5 HMA inches

Layer Type Description

HMA

HMA

HMA

H M A

Surface 1.375 HMA

Bo nd

Q ua lit y

St rip pi ng

De te rio ra tio n

C1 6"

0.5

2.375Binder

Base

Total Depth 5.125

5/31/2025

Brown Crushed Aggregate Base

Brown Crushed Aggregate Base

Appendix C2: MATERIAL SAMPLING

PHOTO DOCUMENTATION LOG

Brown Crushed Aggregate Base

CONG-0901

Bo nd

Q ua lit y

St rip pi ng

De te rio ra tio n

C2 6"

CONG-0901

2.75

Total Depth 7

Wearing Surface

NPS CONG- Material Sampling - Core Data Summary +NF.xlsx 1 of 3

5/31/2025

Appendix C2: MATERIAL SAMPLING

PHOTO DOCUMENTATION LOG

Sample Number: Dia.:

Location:

Thickness

G G G

Core Notes:

Sample Number: Dia.:

Location:

Thickness

G

Core Notes:

Sample Number: Dia.:

Location:

Thickness

G P G

Core Notes: Tan Crushed Aggregate Base

H M A

Surface 1.5 HMA

Base 3.5 HMA

Surface 1.625 inches

Total Depth 8.5 inches

Bo nd

Q ua lit y

St rip pi ng

De te rio ra tio n

C5 6"

CONG-0010

Brown Crushed Aggregate Base; ½" Wearing Surface included in Surface layer

Layer Type Description

Base 2.5 HMA

H M A

Surface 2 HMA

Binder 2.25 HMA

Binder 1.75 HMA

Bo nd

Q ua lit y

St rip pi ng

De te rio ra tio n

C4 6"

CONG-0901

Layer Type Description

Total Depth 5 inches

Bo nd

Q ua lit y

St rip pi ng

De te rio ra tio n

C6 6"

CONG-0010

Layer Type Description

Crushed Aggregate Base

HMA

Binder

Total Depth 5.5

1.125 HMA

Base 2.5 HMA

H M A

Micro Surface 0.25 HMA

NPS CONG- Material Sampling - Core Data Summary +NF.xlsx 2 of 3

5/31/2025

Appendix C2: MATERIAL SAMPLING

PHOTO DOCUMENTATION LOG

Sample Number: Dia.:

Location:

Thickness

P

Core Notes:

Sample Number: Dia.:

Location:

Thickness

G G G

Core Notes:

Surface 2

U N B O U N D

4.5

HMA

Base HMA

Base 10.5 Gravel w/ Silt & Sand

(GW-GM / A-1-a)

Subgrade 7 Clayey Sand

(SC / A-7-6)

½" Micro Surface included; Fabric @ 12"

Layer Type Description

H M A

Bo nd

Q ua lit y

St rip pi ng

De te rio ra tio n

TP1 6"

CONG-0901

Total Depth 24 inches

Base 5.5 Silty Sand w/ Gravel

(SM / A-1-a)

Subgrade 7.5 Clayey Sand

(SC / A-6)

Total Depth 20 inches

Geofabric at 11" depth

U N B O U N D

HMA2Surface

HMA0.5Micro Surface

H M A

HMA2.75Base

HMA1.75

Bo nd

Q ua lit y

St rip pi ng

De te rio ra tio n

TP2 6"

CONG-0901

Binder

DescriptionLayer Type

NPS CONG- Material Sampling - Core Data Summary +NF.xlsx 3 of 3

Appendix C3 – Laboratory Test Results of Unbound Materials

TP1

Base 6.5-17.0

Gray WELL-GRADED GRAVEL with SILT and SAND

GW-GM

A-1-a(0) 11

TP1

Subgrade 17.0-24.0 Brown CLAYEY SAND

SC

A-7-6(5) 46 22 40

TP2

Base 7.0-12.5 Brown SILTY SAND with GRAVEL

SM

A-1-a(0) 13

TP2

Subgrade 12.5-20.0 Brown CLAYEY SAND

SC

A-6(5) 37 17 47

Liquid Limit

Triaxial Compression

Organic Content

Project: NPS SC - CONG

Atterberg Limits

<2µ

<#200

Sheet 1 of 1

Note: The soil classification is based partially on visual classification unless both grain size and Atterberg limits are performed.

Strain

P er m ea bi lit y (c m /s ec

C on so lid at io n

Strength (psi)

Special Tests

Boring and

Sample Numbers

Refer to Laboratory Test Curves

C om pa ct io n

USCS and

AASHTO

Symbols

Project No.: 60748151

UU

Water Content

SUMMARY OF LABORATORY TEST RESULTS

CIU

Plastic Limit

Depth (ft)

Specific Gravity

Unconfined Compression

Grain Size Dry Unit Weight

(pcf) Classification

LAB_SUMMARY_BLUEBELL_AASHTO 60748151_2025-06-14_NPS SC - CONG.GPJ URS_BLUE.GDT 7/11/25

0.0010.010.1110100

SILT OR CLAY

SAND

COBBLES

coarse finemediumfinecoarse

U.S. STANDARD

SIEVE OPENING IN INCHES U.S. STANDARD SIEVE NUMBERS HYDROMETER

Figure 1

PERCENT FINER

Boring

Sample

Spec

Depth (ft)

% +3"

% Gravel

% Sand

% Fines

% -2µ

Cc

Cu

LL

PL

PI

AASHTO

USCS

w (%)

1.5

Project Number 60748151

July 2025

PARTICLE SIZE DISTRIBUTION

Gray WELL-GRADED GRAVEL with SILT and SAND (GW-GM)

Brown CLAYEY SAND (SC)

Brown SILTY SAND with GRAVEL (SM)

P E

R C

E N

T P

A S

S

IN

G

203/8

3/42

SYMBOL

Particle Size

(Sieve #)

SYMBOL

TP1

Base

6.5-17.0

0.0

45.5

43.7

10.8

1.27

96.71

A-1-a(0)

GW-GM

TP1

Subgrade

17.0-24.0

0.0

3.8

56.4

39.8

A-7-6(5)

SC

TP2

Base

7.0-12.5

0.0

43.5

43.8

12.6

A-1-a(0)

SM

2"

1 1/2"

1"

3/4"

1/2"

3/8"

100.0

78.6

67.4

54.5

42.5

31.5

24.5

19.5

15.4

10.8

100.0

96.2

94.3

79.4

60.8

50.9

44.7

39.8

100.0

95.5

82.0

70.4

65.8

56.5

45.3

34.1

26.5

21.4

17.2

12.6

404 604

GRAVEL

PARTICLE SIZE (mm)

DESCRIPTION AND REMARKS

NPS SC - CONG

S

IE

V E

_B

LU

E B

E

LL

_A A

S H

T O

_2

-0 6-

_N

P S

S C

C

O N

G .G

P J

U R

S _B

LU

E

.G D

T

/1

/2

0.0010.010.1110100

SILT OR CLAY

SAND

COBBLES

coarse finemediumfinecoarse

U.S. STANDARD

SIEVE OPENING IN INCHES U.S. STANDARD SIEVE NUMBERS HYDROMETER

Figure 2

PERCENT FINER

Boring

Sample

Spec

Depth (ft)

% +3"

% Gravel

% Sand

% Fines

% -2µ

Cc

Cu

LL

PL

PI

AASHTO

USCS

w (%)

1.5

Project Number 60748151

July 2025

PARTICLE SIZE DISTRIBUTION

Brown CLAYEY SAND (SC)

P E

R C

E N

T P

A S

S

IN

G

203/8

3/42

SYMBOL

Particle Size

(Sieve #)

SYMBOL

TP2

Subgrade

12.5-20.0

0.0

1.2

52.0

46.9

A-6(5)

SC

2"

1 1/2"

1"

3/4"

1/2"

3/8"

100.0

98.8

95.3

82.9

69.0

60.2

53.5

46.9

404 604

GRAVEL

PARTICLE SIZE (mm)

DESCRIPTION AND REMARKS

NPS SC - CONG

S

IE

V E

_B

LU

E B

E

LL

_A A

S H

T O

_2

-0 6-

_N

P S

S C

C

O N

G .G

P J

U R

S _B

LU

E

.G D

T

/1

/2

Appendix D – Traffic Data for Pavement Design

PAVEMENT INVESTIGATION AND ANALYSIS REPORT Appendix D

Historical Traffic Data Downloaded from NPS Stats Report Viewer (Website: https://irma.nps.gov/Stats/SSRSReports/Park%20Specific%20Reports/Traffic%20Counts?Park=GRCA) https://irma.nps.gov/Stats/SSRSReports/Park%20Specific%20Reports/Traffic%20Counts?Park=GRCA

PAVEMENT INVESTIGATION AND ANALYSIS REPORT Appendix D

Table: Historical Traffic Volume Summary Year Annual Total ADT

2024 75,346 206 2023 78,131 214 2022 65,014 178 2021 70,280 193

Average ADT 198

Table: Design ESAL Calculation for CONG-0010

Class Design AADT Vehicle Distribution (%)

Truck Factor

ESAL 20-Year Design ESAL

Classes 1-3

99.00% 0.0061 9,699 20,629

Class 4 1.00% 0.6806 10,930

Appendix E – AASHTO 1993 Pavement Design Calculations

PAVEMENT INVESTIGATION AND ANALYSIS REPORT Appendix E

AASHTO 1993 Pavement Design Calculations

Project SC192 Pavement Preservation, Multiple Parks in South Carolina Section ID CONG-0010 Design for Structural Adequacy of Existing Pavement

Subgrade Mr (psi) = 7,000 Layer Thickness (in) Layer Coeff. Functional Classif ication Urban Rural

Acceptable terminal servicibility Pt = 2.5 HMA 1.50 0.34 Interstate and other freew ays 85-99.9 80-99.9

Initial servicibility P0 = 4.2 HMA 3.50 0.34 Principle arterials 80-99 75-95

Servicibility loss (DPSI) = 1.7 HMA 0.00 0.34 Collectors 80-95 75-95

Agg. Base 6.00 0.14 Local 50-80 50-80

ADT = 220 Subbase 0.00 0.11 S0=0.40-0.50 for flexible pavement (or overlay) design (I-62&III-82)

% Trucks = 1.0% S0=0.30-0.40 for AC overlay (III-121)

Daily Truck Volume = 2.20 Total Pavement Thickness 11 R ZR

Provided SN 2.54 50 0 60 -0.253

Design Life (Year) = 20.00 70 -0.524 Design ESAL = 20,629 80 -0.841

Reliability, R = 90 85 -1.037

ZR = -1.282 90 -1.282

Standard Deviation S0 = 0.45 91 -1.34

92 -1.405 93 -1.476 94 -1.555

W18 = 20,629 95 -1.645 Required SN = 1.87 96 -1.751

97 -1.881 98 -2.054 99 -2.327

100 -3.75

Pass [Provided SN > Required SN]

Design Inputs Existing Structure AASHTO 1993 Design Input References

P a g e I I-

PAVEMENT INVESTIGATION AND ANALYSIS REPORT Appendix E

AASHTO 1993 Pavement Design Calculations

Project SC192 Pavement Preservation, Multiple Parks in South Carolina Section ID CONG-0901 Design for Structural Adequacy of Existing Pavement

Subgrade Mr (psi) = 7,000 Layer Thickness (in) Layer Coeff. Functional Classif ication Urban Rural

Acceptable terminal servicibility Pt = 2.5 HMA 2.00 0.34 Interstate and other freew ays 85-99.9 80-99.9

Initial servicibility P0 = 4.2 HMA 2.00 0.34 Principle arterials 80-99 75-95

Servicibility loss (DPSI) = 1.7 HMA 3.00 0.34 Collectors 80-95 75-95

Agg. Base 6.00 0.14 Local 50-80 50-80

ADT = 110 Subbase 0.00 0.11 S0=0.40-0.50 for flexible pavement (or overlay) design (I-62&III-82)

% Trucks = 1.0% S0=0.30-0.40 for AC overlay (III-121)

Daily Truck Volume = 1.10 Total Pavement Thickness 13 R ZR

Provided SN 3.22 50 0 60 -0.253

Design Life (Year) = 20.00 70 -0.524 Design ESAL = 10,315 80 -0.841

Reliability, R = 90 85 -1.037

ZR = -1.282 90 -1.282

Standard Deviation S0 = 0.45 91 -1.34

92 -1.405 93 -1.476 94 -1.555

W18 = 10,315 95 -1.645 Required SN = 1.65 96 -1.751

97 -1.881 98 -2.054 99 -2.327

100 -3.75

Pass [Provided SN > Required SN]

Design Inputs Existing Structure AASHTO 1993 Design Input References

P a g e I I-

Appendix F – Construction Cost Estimate Summary

(Class B Estimate will be submitted separately)

PAVEMENT INVESTIGATION AND ANALYSIS REPORT Appendix F

Class C Summary Estimate for all South Carolina Parks

Class C Summary Estimate for the CONG Sections

Note: The added section (CONG-0902) will be included as a “Bid Option” in the Class C Construct Cost Estimate and the 15% Design Plans

Direct Construction

Markups Total Direct Constructio

Markups Total Direct Construction

Markups Total

COWP 334929 $1,869,762 $346,791 $332,795 $679,586 $10,209 $9,797 $20,005 $357,000 $342,591 $699,591 CONG 334914 $615,000 $403,196 $403,613 $806,809 $16,801 $16,819 $33,620 $419,997 $420,432 $840,429 KIMO 334920 $1,155,041 $987,432 $1,081,349 $2,068,780 $9,669 $10,589 $20,257 $997,101 $1,091,937 $2,089,038 NISI 334915 $121,000 $14,000 $16,030 $30,030 $9,608 $11,001 $20,610 $23,608 $27,031 $50,639

Total $3,760,803 $1,751,419 $1,833,786 $3,585,205 $46,287 $48,205 $94,492 $1,797,706 $1,881,991 $3,679,697

Base Bid Options Total W. Options Park PMIS #

PMIS Estimated Budget

ROUTE ID ROAD FMSS#

PAVEMENT

TYPE

PROPOSED TREATMENT

COST W/O

MARKUPS

TOTAL

MARKUP

COST W/

MARKUPS

PMIS ESTIMATED

BUDGET

CONG-0010 ENTRANCE ROAD 49065 Asphalt CRACK SEAL & REJUVENATOR w/

LOCALIZED PATCHING

210,396$ 210,613$ 421,009$ 349,706$

CONG-0100

LONGLEAF CAMPGROUND

ACCESS ROAD

241978 Asphalt CRACK SEAL & REJUVENATOR 1,885$ 1,887$ 3,772$ 24,118$

CONG-0900 VISITOR CENTER FIRST PARKING 49064 Asphalt CRACK SEAL & SEAL COAT 68,839$ 68,910$ 137,749$ 84,412$

CONG-0901 VISITOR CENTER BUS PARKING 225801 Asphalt ASPHALT MILL & OVERLAY 73,752$ 73,828$ 147,580$ 72,353$

CONG-0902 EMPLOYEE PARKING 241977 Asphalt SEAL COAT w/ LOCALIZED

PATCHING

16,801$ 16,819$ 33,620$ -$

CONG-0909 VISITOR CENTER MIDDLE PARKING 225800 Asphalt CRACK SEAL & SEAL COAT 48,324$ 48,374$ 96,699$ 84,412$

Total Base Bid 403,196$ 403,613$ 806,809$ 615,000$

Total Options 16,801$ 16,819$ 33,620$ -$

Total 419,997$ 420,432$ 840,429$ 615,000$

Appendix G – Construction Schedule Summary

PAVEMENT INVESTIGATION AND ANALYSIS REPORT Appendix F

PARK ID PMIS # Duration (days) 1-Jun 8-Jun 15-Jun 22-Jun 29-Jun 6-Jul 13-Jul 20-Jul 27-Jul 3-Aug 10-Aug 17-Aug 24-Aug 31-Aug

COWP 334929 41

CONG 334914 34

KIMO 334920 20

NISI 334,915 13

ROUTE ID ROAD PROPOSED TREATMENT 20-Jul 21-Jul 22-Jul 23-Jul 24-Jul 27-Jul 28-Jul 29-Jul 30-Jul 31-Jul 3-Aug 4-Aug 5-Aug 6-Aug 7-Aug 10-Aug 11-Aug 12-Aug 13-Aug 14-Aug 17-Aug 18-Aug 19-Aug 20-Aug 21-Aug

CONG-0010 ENTRANCE ROAD

CRACK SEAL & REJUVENATOR

w/ LOCALIZED PATCHING

CONG-0100

LONGLEAF CAMPGROUND

ACCESS ROAD

CRACK SEAL & REJUVENATOR

CONG-0900

VISITOR CENTER FIRST

PARKING

CRACK SEAL & SEAL COAT

CONG-0901

VISITOR CENTER BUS

PARKING

ASPHALT MILL & OVERLAY

CONG-0902 EMPLOYEE PARKING

SEAL COAT w/ LOCALIZED

PATCHING

CONG-0909

VISITOR CENTER MIDDLE

PARKING

CRACK SEAL & SEAL COAT