Statement of Work.pdf

Statement of Work Preservation and Stabilization of

Large Detached Powder Magazine Fort Jefferson, Garden Key Dry Tortugas National Park

Scope: Large Detached Powder Magazine

The objective of this project is to Preserve the structure. Treatment to stabilize the Large Detached Powder Magazine will require limited repairs to small isolated areas of brick loss and more widespread repointing of deteriorated mortar. No conditions were observed that threaten the short-term stability of the structure; however, areas where bricks have fallen from the wall should be repaired as a priority to avoid the permanent loss of historic fabric and the development of more significant failures requiring greater intervention and investment of resources. Overall, the Large Power Magazine appears stable and little to no structural intervention is required.

Treatment shall include the following:

• Remove volunteer plants and vegetation from the structure. Plants shall be removed and killed in a way that prevents regrowth/resprouting.

• Repoint areas where mortar has deteriorated or lost its binding qualities.

o Develop compatible repair mortars based on results of materials analysis. At least two mortar types appear to have been used in the construction of the Large Detached Powder Magazine, The mortar used to lay up the walls appears to be a natural cement mortar similar to that used in the construction of the scarp walls. A second mortar type was used to point the brick masonry walls. Analysis reveals the pointing mortar to be a lime mortar with no evidence of gypsum or other cementitious materials observed (See Large Detached Magazine HSR-Appendix C).

• Reconstruct isolated areas of masonry collapse/brick loss at top of exterior walls, building corners and ventilation channels using salvaged brick.

• Fill in gaps and crevices in coral concrete infill to prevent erosion of material and unchecked moisture infiltration.

• Preserve areas of masonry damage along west elevation presumed to be caused during the historic period when the south wall was used as a backstop for small arms target practice.

Refer to Historic Structure Report (Large Detached Magazine FINAL Report), drawings (Large_Detached_Magazine_Drawings_FINAL), and project specifications (DRTO_TBD_FINAL_Specifications and) for additional details about the treatment.

All work shall be conducted under the guidance and in accordance with the Secretary of the Interior's Standards for Treatment of Historic Properties.

Performance Period: The work of this Task Order shall be completed from approximately July to November of any calendar year from 2020 to 2022 (July to November 2020, July to November 2021, July to November 2022). Timing of the work shall be coordinated with the COR and will be based on the availability of government housing.

The location of the project for which these services are contracted is Garden Key, Dry Tortugas National Park.

I. PROJECT BACKGROUND

Fort Jefferson is a 19th century “Third System” coastal defense fortification. Military engineers began construction on the fort in 1846 and stopped before it was completed in 1874. It was part of an organized effort by the United States government beginning in 1817 to generate a system of national defense. Each of these coastal defense works were designed to contain artillery, garrisons, and magazines of which could defend against an attack until further reinforcements could be dispatched. Fort Jefferson represents one of the highest achievements of 19th century American military architecture and engineering and is one of the largest Third System forts constructed. The hexagonal fortification has three tiers and surrounds a parade ground with auxiliary structures and ruins.

These auxiliary structures within the interior of the fort consist of a highly organized system of armament and ordinance supply including a hot shot furnace, multiple detached powder magazines at the ground level, and magazines on the first tier constructed within the fortification.

Additionally, there are quarters for officers and soldiers within the parade ground. Each of these structures individually has historic value and collectively are essential resources of the army period of significance at Dry Tortugas National Park. The NPS has received donation funding from the HTR Foundation and recreation fee funding to preserve and stabilize the Large Detached Powder Magazine. The structure included in this scope of work is identified as contributing historic features of Fort Jefferson which is on the National Register of Historic Buildings. The 1974 National Register documentation established that the fort and associated resources were significant in the areas of Military and Engineering.

Large Detached Powder Magazine: Located near the northeastern bastion inside the fort, this barrel-vaulted magazine was built to serve as the main powder storage area. The multi-wythe brick masonry structure sits on a slate water table course, which is above a below-grade concrete bearing wall. The foundation is a wood grillage laid on a sand base. The structure is roughly 56 feet by 80 feet, including the primary magazine structure of about 60 feet, a fortified vestibule of about 15 feet, and ventilation chimney of about 4 feet. The 8-foot thick walls rise to 14 feet and 8 inches, thought their full finished height was meant to be roughly 20 feet and 9 inches. Rising above the walls another 15 feet and 8 inches is the principal barrel-vaulted arch, which consists of four independent wythes of brick. The thickness of the walls is not entirely brick; in nonbearing portions the walls are filled with a coral aggregate and natural cement mix. The walls feature narrow openings as part of a passive ventilation system. The magazine is structurally sound, except for bricks on the parade ground face, which have been extensively damaged by weapons being fired by soldiers into the side of the magazine.

Below the water table course, the interior of the magazine features the angled concrete walls and concrete floor of a cistern, divided in to four chambers by brick partition walls. Above the water course is an open area flanked by four vaults along each long wall. A modern flight of brick stairs leads diagonally down to the floor of the cistern and to some interpretive signage. The vestibule, which is about 20’ narrower than the main structure, features door openings on both its short sides, at the intersections with the end wall of the magazine. The door openings lead to vaulted corridors that first lead away from the magazine at right angles to the doors, then join and return back towards the magazine through a narrow opening. Each opening, two from the parade ground in to the vestibule and one from the vestibule to the magazine, were to have iron-reinforced wood doors. Some brass pintels still remain in stone masonry within the door frames.

Missing brass pintels appear to have been forcibly removed as evidenced by patterns of missing and damaged brick.

II. STANDARDS (See project Specifications for details)

All Research and Documentation shall comply with the standards outlined in:

• National Park Service Director’s Order #28: Cultural Resource Management Guideline

All treatment shall comply with the latest versions of the following:

• Dry Tortugas National Park Enabling Legislation

• The Secretary of the Interior's Standards for the Treatment of Historic Properties

• NPS DO #28: Cultural Resource Management Guidelines

• Project material specifications and drawings

DATA AND MATERIALS TO BE PROVIDED BY NPS:

• National Park Service Director’s Order 28 (NPS-28)

• Historic Structure Report for Large Detached Magazine, Lord Aeck Sargent; 2017 o Documents also include materials analysis data o Documents include treatment drawings for Large Detached Magazine

• Historic Photographs and Drawings of Fort Jefferson, and auxillary structures on file

• Other applicable park planning documents as requested including but not limited to:

o Historic Structures Report (HSR), Edwin Bearss, 1983 o Historic Structures Report Amendment (HSR-A), LAS, 2006 o Dry Tortugas Cultural Landscape Report (CLR), Susan Hitchcock/Beth Byrd, o Long Range Interpretive Plan (LRIP), NPS-Harpers Ferry, 2003

• Local sand (un-sifted) and cistern water will be available for concrete/mortar mixing

III. GENERAL DESCRIPTION OF WORK:

The treatment of this project includes the preservation and stabilization of one structure; Large Detached Powder Magazine.

Project work includes all delivery and removal of construction materials, equipment, power generation, supplies, project debris, and domestic trash; all scaffolding delivery, assembly, disassembly required for access to work site, any and all safety barricades required as well.

• Site Visits:

o Due to the remote location, specific site logistics, and challenging working conditions of any project at the Dry Tortugas a site visit may be required prior to submission of your proposal. Site visits can be used to collect or verify measurements and quantities, quantify materials, establish construction methods, and to have site familiarity. Site visits shall be rendered by the COR assigned to the project under this SOW. The NPS reserves the right to limit site visits to those which the CO or the COR determines to be sufficient.

o Site visits prior to award will not be reimbursable by the government.

o Transportation to Dry Tortugas is offered daily by two separate commercial operations: Yankee Freedom III ferry; roughly 2.5 hours each way, 0800 departure from Key West to Dry Tortugtas and a 1430 departure from Dry Tortugas to Key West. Key West Seaplane Adventures offers multiple seaplane departures from Key West to Dry Tortugas Daily. Travel time is roughly 45 minutes each way. Contractor shall verify all transportation logistics with vendors directly.

• Park Housing:

o Park housing will be made available to contractor for a crew of up to ten (10) individuals. Park housing is a shared living situation. See project specifications for more detailed information. A walk through can be completed with a site visit and/or more information can be provided upon request Housing rates are $45/person/night to be paid to park at the end of each month of occupation

• Telephone/Internet:

o The internet provided to transient quarters is very limited, with capability for texting and browsing webpages. Very strict usage rules apply as it is a community system.

o No government-provided phone service will be available to the contractor.

o Contractor will be responsible for all telecommunications needs and systems beyond the capabilities of what is provided currently by the NPS. This must be heavily coordinated with the designated CO as options for phone and internet are incredibly limited on Garden Key.

• General Treatment o Delivery all materials, supplies, personnel, and equipment required to complete the scope of work including but not limited to barricades, safety equipment, power generators, sand screeners, scaffolding, water pumps/containers, materials, tools, food, drink, recreation equipment.

https://www.drytortugas.com/ http://keywestseaplanecharters.com/ o Assemble scaffolding in accordance with all applicable state and federal requirements o See project drawings and specifications for scope details, material and workmanship requirements o Remove all materials, supplies, and equipment from Dry Tortugas National Park upon completion of the project

• Documentation o Contractor shall follow all project specifications for documentation, which includes at a minimum daily project reporting, photographic documentation, “As- Built” drawings, and Operations and Maintenance procedures/plan. All documentation shall be submitted to the park COR at close out.

IV. SCHEDULE AND SUBMISSIONS

A. Schedule This work season(s) for this project is from July to November of any calendar year from 2020 to 2022 (July to November 2020, July to November 2021, July to November 2022). Timing of the work shall be coordinated with the COR and will be based on the availability of government housing. Dry Tortugas National Park is subject to seasonal Atlantic Hurricane conditions from June to November. Contractor will be responsible for planning, scheduling, and executing any temporary closures or shutdowns of the work site due to severe weather; any time of the year, but particularly during the hurricane season. Evacuations and seasonal shutdowns may be required.

See Project Specifications for schedule submittals and day to day work schedule restrictions. No official contract work shall begin until after award and a Notice to Proceed have been provided by the Contracting Officer.

B. Final Submissions-Project Close Out:

Reference the Project Specifications Section 01 77 00-Close Out Procedures and Submittal List.

Produce and submit to NPS the final documents on computer disks in the current versions of MicroStation or AutoCAD format for drawings, MS-Word format and PDF (Adobe Acrobat portable document format) for texts in order to comply with DOI (Department of the Interior) e-commerce requirements, MS-Excel for spreadsheets, or other format as directed by the Contracting Officer. All PDF files are to be generated directly from the electronic files--scanning printouts is unacceptable.

All files shall be unprotected (no required passwords). Organization of CAD files on compact disks, and organization of drawing levels within the CAD files shall comply with the Denver Service Center CADD User's Guide.

Submission of the final documents shall include:

• Two electronic copies on compact disks of all graphic and text files

• Three sets of manufacturers' cut sheets of all critical products and equipment; double-sided bound on 8½" × 11" white paper

• All original project photographs in .jpeg format

• As-Built drawings The Contracting Officer may allow electronic transfer on computer files in lieu of compact disks.