Attach_9_MUHJ_03-4247_Final_Basis_of_Design.pdf

MUHJ 03-4247—Repair East Apron, Phase 9, F.6020

Joint Base Langley-Eustis, Langley AFB, Hampton, VA

Basis of Design

100% Submission September 16, 2016

BASIS OF DESIGN/DESIGN ANALYSIS

REPAIR EAST APRON, PHASE 9

Project MUHJ 03-4247

GENERAL DESCRIPTION

The scope of work for this project includes the replacement of the T-38 parking area on the East Apron, Facility 6020 and design of a pavement typical section to be used for the reconstruction of the Brownie Pad at Langley Air Force Base. Repairs include the removal of the existing pavement section including the aggregate base and sub-base, unclassified excavation, placement of a new sub-base and base section, concrete pavement, replacement of the existing box drain, 24” reinforce concrete pipe replace, manhole modifications, aircraft tie-downs, and pavement markings. Environmental testing is also required to determine if the existing subgrade material contains any contaminates prior to disposing of it off-base.

BACKGROUND

The intent of this project is to provide an assessment of the existing condition of the East Apron This project is Phase 9 of a multi-phase effort to recapitalize airfield parking aprons at Langley AFB. , The previous eight phases were completed through a single bidder Indefinite Delivery / Indefinite Quantity

(IDIQ) pavement construction contract.

The scope of this project is based on information provided in the Statement of Work, Architectural and

Engineering Services for Project MUHJ 03-4247, Repair East Apron, Phase 9, Facility 6020 at JBLE-

Langley, Virginia; Airfield Pavement Condition Index Survey Report – November 2006, Prepared By:

Applied Pavement Technology, Inc.; Airfield Pavement Condition Index Survey Report – November 2010, Prepared By: Applied Research Associates, Inc.; Airfield Pavement Condition Index Survey Report –

November 2014, Prepared By: Applied Research Associates, Inc.; Airfield Pavement Evaluation –

January 2015, Prepared By: Air Force Civil Engineer Center (AFCEC); Composite utility systems map:

Stormwater Infrastructure Map 2015; as well as two site visits.

ASSESSMENT

Data Collection

As part of the data collection for this project, the project area was surveyed including getting information on all sub-surface utilities.

Geotechnical Investigation

Six 4-inch diameter borings to a depth of 6-feet were taken at random locations on the project to determine the existing pavement section and characteristics of the soil conditions to be used in designing the proposed pavement section. Laboratory testing was completed to determine the soil classifications of the six borings in accordance with ASTM D2488. Laboratory test results showed the USCS Classification to be Silty and Clayey Sand (SM and SC) and the Atterberg Limits to be non plastic. The average in-situ

California Bearing Ratio (CBR) values ranged from 2.7 to 22.3. The Geotechnical are included under separate cover.

Environmental Soil Testing

On January 12, 13, and 14 of 2016, six soil borings were advanced using a hand auger to a depth of 4.5 to

6 feet below land surface (BLS) to assess soil quality and to determine if the soil contained any contaminates. Following soil boring advancement, one soil sample was collected at every foot to soil boring termination to evaluate for the presence of organic vapors using a pre-calibrated photoionization detector

(PID). The depth that revealed the highest PID reading was resampled for laboratory analysis. Thus, a total of six soil samples were collected and identified as C-1 through C-6. The soil samples were placed in laboratory supplied sample containers, stored in a cooler chilled with ice for preservation, submitted with chain of custody (COC) documentation, sealed, and sent to Test America of Pensacola, Florida for laboratory analyses for Total Petroleum Hydrocarbons-Diesel Range Organics (TPH-DRO) and Total

Petroleum Hydrocarbons-Gasoline Range Organics (TPH-GRO). Additionally, two composite samples, identified as Comp 1 and Comp 2, were compiled from the same samples with the highest PID readings and tested for Toxicity Characteristic Leaching Procedure (TCLP) – RCRA 8 Metals, TCLP Volatile Organic

Compounds (VOCs), TCLP-pesticides, PCBs, benzene, toluene, ethylbenzene, and xylenes (BTEX), Total

Organic Halides (EOX) and Paint Filter Analysis. Comp 1 is comprised of soil samples C-1, C-4 and C-6.

Comp 2 is comprised of soil samples C-2, C-3 and C-5. No groundwater was sampled.

Based on laboratory results, sample locations C-1, C-2 and C-3 resulted in TPH-DRO or TPH-GRO concentrations that exceed clean fill requirements. All three samples were collected from the area known as the East Apron. Approximately 8,350 cubic yards of contaminated soil is anticipated to be excavated during construction of the proposed improvements. Lawful management and proper disposal is required.

Please reference specification 01 13 00 for management of contaminated soil during construction.

Samples locations C-4, C-5 and C-6 meet the clean fill requirements. All three samples were collected from the area known as the Brownie Pad.

No concentrations indicating potential hazardous levels of contamination were detected in soil samples

Comp 1 and Comp 2.

In summary, no hazardous concentrations were detected. However, with the exception of sample C-5, non-hazardous levels of petroleum constituents were detected in soil. Higher levels that are not suitable for re-use were detected within the limits of the East Apron. Thus, excavated soil from this area is contaminated and therefore needs to be properly managed in accordance with specification 01 13 00.

Lower levels of petroleum were detected within the limits of the Brownie Pad. Lawful re-use or disposal is required for excavated soil within the limits of the Brownie Pad.

Environmental Reports are included under separate cover.

Existing Conditions – Apron Pavement

The existing East Apron, Facility 6020 at Langley Air Force Base consists of approximately 16.75-inches

Portland Cement Concrete (PCC) Pavement in two layers, 9.75 inches and 7.0-inches with a bond breaker in between and additional underlying support layers. Since 2007 three visual Pavement Condition Index

(PCI) surveys have been completed, 2007, 2010, and 2014, by various Consultant teams. A structural evaluation was completed in 2015 by the AFCEC.

The pavement section considered for reconstruction as part of this project was identified as Section A24B1 in 2007 and 2010 and was subsequently changed to A24B in 2014. The PCI value of Section A24B1 in

2007 was determined to be 70. Distresses observed at that time included primarily a combination of climate/age- and material-related distresses including small/large patching, joint spalling, corner spalling, joint seal damage, and durability cracking. The majority of the distresses at that time were limited to low-and medium-severity levels; although the joint seal damage was recorded as high-severity throughout the section and isolated areas of high-severity joint spalling was recorded. In 2010 the PCI of Section A24B1 increased from 70 to 78. The Airfield Pavement Condition Index Report completed by Applied Research

Associates, Inc. (ARA) indicated that the increase in PCI may be attributed to “suspected joint seal repair and spall repair”.

In reviewing the PCI data collected it appears that a lesser quantity of joint and corner spalling was recorded whereas an increased amount of patching was recorded. Additionally, the majority of the joint sealant was rated at medium-severity levels. The major difference observed in the 2010 PCI data when compared to the 2007 data is that very limited amounts of durability cracking were recorded in 2010.

Although it is possible areas of durability cracking observed in 2007 were properly addressed through

PCC patching techniques it is unlikely all areas of durability cracking were addressed. The fact that no durability cracking was observed and recorded in 2010 compared to 2007 could have a significant impact on the increase in PCI observed. A third PCI survey was completed in 2014 which indicated a decrease in the PCI for section A24B from 78 to 75. Similar distresses were once again recorded in 2014 as compared to 2010. Lastly, an Airfield Pavement Evaluation was completed by AFCEC in 2015.

Although the focus of this study was primarily to evaluate the structural condition of the airfield pavement a cursory PCI survey was conducted. A PCI value was not determined as part of this evaluation for Section

A24B; however, general notes were made regarding the type and severity of distresses observed. These observations aligned well with previous visual evaluations. The condition of the apron pavement at the time of the site visit in December 2015, exhibited some of the same distresses as noted in previous evaluations with durability cracking, numerous concrete and asphalt patches, joint spalling and corner spalling, and failing joints.

Existing Conditions – Storm Sewer

The existing storm drainage structures appear original and do not meet current structural design standards. The 24” reinforced concrete pipe (RCP) still needs to be evaluated to determine if it can be reused but with the reconstruction of the pavement, it would be recommended to replace the existing reinforced concrete pipe. The box drain appears to be in good condition but will be difficult to salvage with the replacement of apron pavement around the box drain.

DESIGN

Criteria

Design will be in accordance to Unified Facilities Criteria (UFC) 3-260-01 Airfield and Heliport Planning and Design; UFC 3-260-02 Pavement Design for Airfields; UFC 3-250-04 Standard Practice for Concrete

Pavements; UFC 3-250-08 Standard Practice for Sealing Joints and Cracks in Rigid and Flexible

Pavements; UFC 3-250-11 Soil Stabilization for Pavements; Engineering Technical Letter (ETL) 04-2

(Change 1): Standard Airfield Pavement Marking Schemes; and Unified Facilities Guide Specifications.

New Pavement Design

A new PCC pavement design was developed in accordance with United Facilities Criteria (UFC) 3-260-02

Pavement Design for Airfields. For the purpose of this pavement design, a geotechnical investigation was completed to determine in-situ subgrade support conditions, California Bearing Ratio (CBR) or Modulus of

Subgrade Reaction (k-value). In total, six in-situ subgrade CBR tests were completed within the identified project area. The in-situ CBRs ranged from 22.3 to 2.7. For the design, the high and low values were discarded and the average minus one standard deviation of the remaining four CBRs was used for design.

This resulted in a design CBR value of approximately 6.4 which converts to a design k-value of 100 lbs/in3 for rigid pavement design.

Kimley-Horn was provided direction to use Type B Light Load as the design traffic type by the Langley Civil

Engineering 633 CES/CEN. The aircraft within this design group considered in the design are summarized below:

C-17A Globemaster III – 585,000 lbs. – 400 passes

F-15D Eagle – 68,000 lbs. – 400,000 passes

The design flexural strength of the PCC to be used in the design was determined to be 650 psi.

Using the design inputs summarized above a new PCC pavement design was completed using the PCASE

Version 2.09.05 software package. The recommended PCC pavement design is summarized below:

13-inch PCC

12-inch Crushed Aggregate Base Course

6-inch Cement Treated Subgrade

Spacing for construction and contraction joints, dowel bar sizing and spacing was based on the thickness of the proposed PCC section of 13-inches. The joint spacing was determined to be 20-feet by 20-feet per

Table 12-7 of the UFC 3-260-02 Pavement Design for Airfields and any irregular shape panels will be reinforced with 6 X 6 – W5 X W5 welded wire fabric. The dowel bar size was determined to be 1-1/4-inches diameter and 20-inches in length with a maximum dowel bar spacing of 15-inches per Table 12-8 of the

UFC 3-260-02 Pavement Design for Airfields. Joint sealant for the project will be preformed polychloroprene compression joint seal for the construction and contraction joints and silicone for the expansion joints.

The PCASE pavement thickness report is attached for reference.

Storm Sewer and Box Drain

The proposed storm sewer is designed using class V reinforced concrete pipe and aircraft rated structures with frame and grates. The box drain was designed based on the detail that was provided by Langley Civil Engineering 633 CES/CEN.

REMEDIATION

Full depth replacement of the apron pavement as well as a new box drain and drainage structures will be required.

Due to age, apparent condition, geotechnical information and a value engineering judgment the existing apron pavement needs to be reconstructed.

Storm sewer manholes will need to be replaced and brought up to proposed standards and grades.

Replace the existing 24” storm sewer.

Replace the existing tie-downs.

SUMMARY

This project recommends the following actions:

24,481 square yards of pavement removal

24,481 square yards of concrete replacement

10,905 cubic yards of aggregate base

4,090 cubic yards of cement treated subgrade

474 feet of box drain

448 feet of 24” RCP

5 storm sewer structures

28 tie-downs

4,728 feet of pavement marking