MT NP GLAC P HQ (1)_Amended Final Pavement Memo.pdf

158377846

Memorandum Western Federal Lands Highway Division

610 E. Fifth Street Vancouver, WA 98661

DATE: March 6, 2024

TO: Michael Traffalis, Project Manager

FROM: Nassim Sabahfar, Materials Engineer

SUBJECT: Amended Final Pavement Structure Recommendations Rehabilitation of Glacier Headquarters Parking Area

MT NP GLAC P HQ (1)

Background

This memorandum is an amendment to the pavement rehabilitation recommendations provided on January 28, 2023 as a single report titled Pavement Evaluation Report and Pavement Rehabilitation Recommendation. The mentioned report is attached to this memorandum as Appendix A.

The amended memorandum is prepared based on the directions received from the Project Manager in regard to funding restrictions and changes in schedule. The original recommendations (Appendix A) were provided considering the type of natural soil encountered in the area, the frost depth in the corridor, and the frequency of frost heave damage in the region.

The requested amendments will potentially make the pavement structure susceptible to earlier onset of frost heave damage.

Amended Pavement Design Recommendation for Glacier Headquarters Parking Area;

Phase 1 and Phase 2

Table 1 thorough 4 provide the amended pavement design recommendations for Phase 1 and Phase 2 of Glacier Headquarters Parking Area. Recommendations for Phase 3 and Phase 4 are removed due to possible changes in schedule dependent on cost estimates after completion of preliminary plans.

Table 1 – Phase 1 - Back (East) Parking Lot, Schedule A Thickness (inches) Description

4 Asphalt Concrete Pavement (Section 403, estimated @ 1.94 tons/cuyd) 8 Roadway Aggregate, Method 2 (Section 302, estimated @ 1.97 tons/cuyd)

Table 2 – Phase 1 - Back (East) Parking Lot, Schedule B Thickness (inches) Description

4 Asphalt Concrete Pavement (Section 403, estimated @ 1.94 tons/cuyd) 8 Roadway Aggregate, Method 2 (Section 302, estimated @ 1.97 tons/cuyd) 6 Select Borrow (Section 204, estimated @ 1.85 tons/cuyd)

Phase 1 – Front (West) Parking Lot is removed from the project scope.

Table 3 – Phase 2, Schedule A Thickness (inches) Description

4 Asphalt Concrete Pavement (Section 403, estimated @ 1.94 tons/cuyd) 8 Roadway Aggregate, Method 2 (Section 302, estimated @ 1.97 tons/cuyd)

Table 4 – Phase 2, Schedule B Thickness (inches) Description

4 Asphalt Concrete Pavement (Section 403, estimated @ 1.94 tons/cuyd) 8 Roadway Aggregate, Method 2 (Section 302, estimated @ 1.97 tons/cuyd) 6 Select Borrow (Section 204, estimated @ 1.85 tons/cuyd)

The recommended asphalt binder grade for the location is PG 58-34 and it is recommended that asphalt concrete pavement layer be placed in two lifts with tack coat applied between the lifts.

Recommended tack coat application rate is 0.1 gal/sqyd.

Special Contract Requirements

Materials will provide pavement special contract requirements (SCRs) if necessary.

Follow Up

Please notify Materials if changes to the assumptions occur which may require revisions to this pavement design memo.

Appendix A

Rehabilitation of Glacier Headquarters Parking Area

Pavement Evaluation Report and Pavement Rehabilitation Recommendation

Federal Highway Administration Western Federal Lands Highway Division

Pavement Evaluation Report And

Pavement Rehabilitation Recommendation Glacier National Park

Rehabilitation of Glacier Headquarters Parking Area Flathead County, Montana

MT NP GLAC P HQ (1)

June 2022

Rehabilitation of Glacier Headquarters Parking Area i

TABLE OF CONTENTS

1 Description of Review

2 Pavement Distress Evaluation and Rehabilitation Recommendations

2.1 Phase 1 – Pavement Distress Evaluation

2.2 Phase 1 – Final Pavement Rehabilitation Recommendation

2.3 Phase 2 – Pavement Distress Evaluation

2.4 Phase 2 – Pavement Rehabilitation Recommendation

2.5 Phase 3 – Pavement Distress Evaluation

2.6 Phase 3 – Pavement Rehabilitation Recommendation

2.7 Phase 4 – Pavement Distress Evaluation

2.8 Phase 4 – Pavement Rehabilitation Recommendation

LIST OF FIGURES

Figure 1. Park headquarters phase area limits aerial view

Figure 2. Phase 1 of Park Headquarters, drainage issue in the front (west) parking lot

Figure 3. Phase 1 of Park Headquarters, back (east) parking lot a) severe fatigue cracks, raveling, and potholes, b) standing water in the parking lot, and c) failed patch

Figure 4. Phase 1 of Park Headquarters, nonfunctional inlet on the back (east) parking lot

Figure 5. Pavement distresses on phase 2 of Park Headquarters a) severe fatigue cracks caused by frost heave action b) cracks and depression, c) moderate fatigue cracks

Figure 6. Pavement distresses on phase 2 of Park Headquarters d) fatigue cracks turned into potholes, and e) potholes

Rehabilitation of Glacier Headquarters Parking Area ii

Figure 7. Pavement distresses on phase 3 of Park Headquarters a) uneven surface created by inappropriate chip seal b) raveling of the poorly patched pothole, c) polished aggregates and transverse cracks, and d) poor patching

Figure 8. Poor drainage leading to accumulation of water on the roadside and causing edge deterioration (phase 3 of Park Headquarters)

Figure 9. Pavement distresses on phase 4 of Park Headquarters a) severe fatigue cracks, raveling, depression, and potholes, b) fatigue cracks, raveling, and potholes,

c) standing water in the parking lot, and d) improper patching and depression

LIST OF TABLES

Table 1. Recommended pavement rehabilitation for Glacier Park Headquarters

Rehabilitation of Glacier Headquarters Parking Area 1

1 Description of Review

On June 13 - 15, 2022 a pavement evaluation was conducted in Glacier National Park by Corbin Williams and Nassim Sabahfar, Western Federal Lands Highway Division (WFL) Civil Engineer in training and Materials Engineer. The intent of this investigation was to evaluate general pavement performance along a selection of specific routes within the park including Glacier Headquarters Parking Area. Glacier headquarters parking area encompasses multiple parking areas and a section of Grinnel Drive that provides access to Park headquarters office, community building, and residential areas.

The investigations entailed visual evaluation of the pavement conditions by traversing the sections by foot. Pavement conditions were logged in by hand with accompanying photographic documentation and GPS positioning.

Glacier Park Headquarters pavement rehab is planned to be completed in four phases. Figure 1 shows the location for each phase.

Figure 1. Park headquarters phase area limits aerial view

Rehabilitation of Glacier Headquarters Parking Area 2

2 Pavement Distress Evaluation and Rehabilitation Recommendations

2.1 Phase 1 – Pavement Distress Evaluation

Phase 1 includes parking lots in front (west) and back (east) of the Glacier National Park headquarters building. The back (east) parking lots is in a very poor condition with severe distress throughout the entirety of the lot. Severe fatigue cracks, caused by frost heave action are frequent.

Block cracks, potholes, raveling, and improper patching are present as well.

The front (west) parking lot is generally in good condition with the majority of distresses in low to medium severity. Drainage is a major issue in both parking lots with standing water present in almost entirety of the area. There are inlets in the parking lots but they are clogged and nonfunctional.

Figure 2 shows the general condition of the front parking lot and Figure 3 shows multiple distresses in the back parking lot. Figure 4 shows the nonfunctional inlet on the back parking lot.

Rehabilitation of Glacier Headquarters Parking Area 3

Figure 2. Phase 1 of Park Headquarters, drainage issue in the front (west) parking lot

Rehabilitation of Glacier Headquarters Parking Area 4

Figure 3. Phase 1 of Park Headquarters, back (east) parking lot a) severe fatigue cracks, raveling, and potholes, b) standing water in the parking lot, and c) failed patch

Rehabilitation of Glacier Headquarters Parking Area 5

Figure 4. Phase 1 of Park Headquarters, nonfunctional inlet on the back (east) parking lot

2.2 Phase 1 – Final Pavement Rehabilitation Recommendation

The recommendations for rehabilitation of Phase 1 of Park Headquarters are provided based on the general assessment of the pavement condition and the results obtained from testing the soil samples. Soil samples were obtained from a single drilling performed on the front (west) parking lot. The boring log shows the thickness of asphalt concrete pavement (ACP) as 8 inches. Tests conducted in WFL Materials Laboratory on the underlying soil indicate that the ACP is placed on top of the natural soil, classified as A-2-4 (following AASHTO M 145). The soil sample, extracted from the depth of 8 inches to 48 inches, contained about 14% of particles smaller than 0.02 millimeters. As a general rule, inorganic soils containing 3% or more of particles finer than 0.02 millimeters are considered frost susceptible. Presence of frost susceptible soil is in conformity with significant frost heave damage observed in the area.

Based on the frequency and severity of the frost heave damage observed on the corridor and based on the information provided by Flathead County, the frost depth for Glacier Headquarters Parking Area is assumed to be 60 inches. To prevent premature damage on the pavement structure caused by frost heave action, pavement structure thickness is recommended to be minimum of half of the

Rehabilitation of Glacier Headquarters Parking Area 6 depth of frost penetration in areas with prominent frost heave damage. Therefore, the controlling factor in design of pavement structure is the frost depth as part of the frost susceptible soil will be replaced with granular material. The recommended structure for Phase 1 of Glacier Headquarters Parking Area is:

Front (West) Parking Lot:

- Asphalt Pavement Crack Sealing and Filling (Section 414)

- Chip Seal Type 1C (Section 407)

Back (East) Parking Lot:

- 4 inches – Asphalt Concrete Pavement (Section 403, estimated @ 1.94 tons/cuyd)

- 8 inches – Roadway Aggregate, Method 2 (Section 302, estimated @ 1.97 tons/cuyd)

- 18 inches – Select Borrow (Section 204, estimated @ 1.85 tons/cuyd)

It is recommended that asphalt concrete pavement layer be placed in two equal lifts with tack coat applied between the lifts.

2.3 Phase 2 – Pavement Distress Evaluation

Phase 2 parking and driving area is subdivided into two sections; A and B. Section A is the north section of the paved area that stretches from Grinnel Drive to the maintenance fuel station. Section B continues southeast from the fuel station and includes all paved surfaces up to Phase 4. Both sections of Phase 2 are in very poor condition. Moderate to severe fatigue cracks, caused by frost heave action, are frequent throughout the area along with depressions and raveling. Drainage is a major issue in both sections with standing water present in almost entirety of the area. Figure 5 and Figure 6 show multiple distresses in Section A and Section B of Phase 2.

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Figure 5. Pavement distresses on phase 2 of Park Headquarters a) severe fatigue cracks caused by frost heave action b) cracks and depression, c) moderate fatigue cracks

Rehabilitation of Glacier Headquarters Parking Area 8

Figure 6. Pavement distresses on phase 2 of Park Headquarters d) fatigue cracks turned into potholes, and e) potholes

Rehabilitation of Glacier Headquarters Parking Area 9

2.4 Phase 2 – Pavement Rehabilitation Recommendation

The recommendations provided here are based on general assessment of the pavement condition during the field visit in June 2022. The pavement design recommendations should be reexamined once subsurface explorations are completed and laboratory test results are available on samples tested for Phase 2. The recommended structure for Phase 2 of Glacier Headquarters Parking Area is:

- 4 inches – Asphalt Concrete Pavement (Section 403, estimated @ 1.94 tons/cuyd)

- 8 inches – Roadway Aggregate, Method 2 (Section 302, estimated @ 1.97 tons/cuyd)

- 18 inches – Select Borrow (Section 204, estimated @ 1.85 tons/cuyd)

2.5 Phase 3 – Pavement Distress Evaluation

Phase 3 covers a portion of Grinnel Drive stretching from Glacier Route 1 Road to Mather Drive.

Uneven surfaces created by inappropriate chip seal, transverse cracks, polished aggregates, and poor patches are major distresses on this section. In addition, drainage is an issue with water accumulation on both sides of the road aggravating pavement edge deterioration. Figure 7 shows multiple distresses on the segment and Figure 8 shows water accumulation on the roadside.

2.6 Phase 3 – Pavement Rehabilitation Recommendation

The recommendations provided here are based on general assessment of the pavement condition during the field visit in June 2022. The pavement design recommendations should be reexamined once subsurface explorations are completed and laboratory test results are available on samples tested for Phase 3. The recommended structure for Phase 3 of Glacier Headquarters Parking Area is:

- 2 inches – Asphalt Concrete Pavement (Section 403, estimated @ 1.94 tons/cuyd)

- 2 inches – Asphalt Pavement Milling (Section 413)

Rehabilitation of Glacier Headquarters Parking Area 10

Figure 7. Pavement distresses on phase 3 of Park Headquarters a) uneven surface created by inappropriate chip seal b) raveling of the poorly patched pothole, c) polished aggregates and transverse cracks, and d) poor patching

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Figure 8. Poor drainage leading to accumulation of water on the roadside and causing edge deterioration (phase 3 of Park Headquarters)

2.7 Phase 4 – Pavement Distress Evaluation

Phase 4 includes the south eastern parking area of the headquarters. The parking is in a poor condition with severe distress throughout the entirety of the lot. Severe fatigue and block cracks are frequent and potholes, raveling, and improper patching are present as well. Drainage is a major

Rehabilitation of Glacier Headquarters Parking Area 12 issue in the parking lot with standing water present in almost entirety of the area. Figure 9 shows multiple distresses in the parking lot.

Figure 9. Pavement distresses on phase 4 of Park Headquarters a) severe fatigue cracks, raveling, depression, and potholes, b) fatigue cracks, raveling, and potholes, c) standing water in the parking lot, and d) improper patching and depression

2.8 Phase 4 – Pavement Rehabilitation Recommendation

The recommendations provided here are based on general assessment of the pavement condition during the field visit in June 2022. The pavement design recommendations should be reexamined once subsurface explorations are completed and laboratory test results are available on samples tested for Phase 2. The recommended structure for Phase 2 of Glacier Headquarters Parking Area is:

- 4 inches – Asphalt Concrete Pavement (Section 403, estimated @ 1.94 tons/cuyd)

- 8 inches – Roadway Aggregate, Method 2 (Section 302, estimated @ 1.97 tons/cuyd)

- 18 inches – Select Borrow (Section 204, estimated @ 1.85 tons/cuyd)

Rehabilitation of Glacier Headquarters Parking Area 13

Table 1 summarizes the pavement rehabilitation recommendations for Phase 1 through 4 for Glacier Park Headquarters.

Table 1. Recommended pavement rehabilitation for Glacier Park Headquarters

Phase Location Recommended Treatment FP – 14 Items

Front (West) Parking Lot

Crack filling/sealing followed by chip seal

Section 407, Chip Seal Type 1C

Section 414, Asphalt Pavement Crack

Sealing and Filling

Back (East) Parking Lot

Reconstruction of the entire parking lot

Section 403, Asphalt Concrete Type I

Section 302, Minor Crushed Aggregate

Section 204, Select Borrow

2 N/A Reconstruction of the entire parking lot

Section 403, Asphalt Concrete Type I

Section 302, Minor Crushed Aggregate

Section 204, Select Borrow

3 N/A 2 inches of mill and overlay

Section 403, Asphalt Concrete Type I

Section 413, Asphalt Pavement Milling

4 N/A Reconstruction of the entire parking lot

Section 403, Asphalt Concrete Type I

Section 302, Minor Crushed Aggregate

Section 204, Select Borrow