Attachment_1_MACA_337611A_SOW_3_31_26.pdf

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Mammoth Cave National Park

STATEMENT OF WORK

Cosmetic Repair of Pedestrian Bridge Foundation

PMIS# 337611

DATED: 11/24/2025

NATIONAL PARK SERVICE

SOUTHEAST REGION

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DIVISION 01 - GENERAL REQUIREMENTS

DIVISION 1 SHORT FORM GENERAL REQUIREMENTS

PART 1 – GENERAL

ITEM 1 - DESCRIPTION OF WORK

1.1 Background:

The existing concrete foundation supporting the pedestrian bridge at Mammoth Cave National Park has experienced minor but visible deterioration, including cracks and surface spalls. Although structural integrity is not currently compromised, timely restoration is essential to preserve aesthetic value, ensure longevity, and mitigate long-term maintenance costs. The bridge plays a vital role in visitor circulation and interpretive engagement at the site.

1.2 Work Covered by the Contract Documents:

Project Location: Mammoth Cave National Park, Kentucky. See PART 3, Item 1 – Site Plan for exact location.

Scope of Work Includes:

The contractor shall furnish all labor, materials, tools, equipment, transportation, and supervision necessary to perform the following tasks in accordance with applicable ACI, ASTM, OSHA, SMACNA, and NPS historical preservation standards:

A. Surface Crack and Spall Repair – Hotel and Visitor Center Sides (Total: 663 SF)

Perform detailed visual and acoustic inspection (chain drag and hammer tap) of all vertical and horizontal concrete surfaces.

Mark all delaminated areas, shrinkage cracks, and spalls.

Prepare surfaces by sandblasting (minimum 5,000 psi) to remove contaminants and loose debris.

For cracks <1/16”, inject low-viscosity epoxy per ASTM C881 using gravity-fed method.

For cracks >1/16” and spalls:

o Chip out unsound concrete to minimum depth of 1.5” with square-edged perimeter cuts.

o Apply epoxy bonding agent to prepared area.

o Fill with non-shrink, polymer-modified mortar meeting ASTM C928.

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Moist cure for 72 hours per ACI 308 using wet burlap and plastic sheeting

B. Beneath-Bridge Substructure Repairs:

Scarification o Mechanically scarify all concrete surfaces beneath the bridge designated for new veneer to a uniform depth of 1/4" to 3/8".

o Use power chisels or milling equipment per ICRI Guideline No. 310.2R.

Formwork & Concrete Placement o Install formwork suitable for vertical overhead surfaces o Dowel into existing substrate using epoxy-coated #4 rebar drilled and epoxied at 12" O.C. vertical spacing.

o Place high-strength, low-shrink concrete (minimum 5,000 psi at 28 days) into forms to match surrounding retaining wall dimensions.

o Vibrate internally to ensure consolidation.

Sandstone Veneer Installation o HOTEL SIDE OF BRIDGE: After 7-day curing, install 150–200 SF of sandstone veneer matching adjacent materials in pattern, thickness, and texture.

o VISITOR CENTER SIDE OF BRIDGE: After 7-day curing, install 100–150 SF of alternating retaining wall blocks matching adjacent materials in pattern, thickness, and texture.

o Use pre-approved thin-set adhesive (ANSI A118.4 compliant) or mechanical anchors as necessary.

o Follow installation per ASTM C1780 and NPS-approved historical standards.

C. Maintenance of Pedestrian Access (Continuous Operations Requirement)

The Contractor shall maintain continuous pedestrian access across the bridge for the duration of the project.

At no time shall the bridge be fully closed without prior written authorization from the Contracting Officer (CO) and Contracting Officer’s Representative (COR).

Maintain a minimum unobstructed clear walkway width of 48 inches (minimum) compliant with ABA/ADA accessibility requirements.

Install temporary barriers, guardrails, and signage per OSHA 29 CFR 1926 Subpart M and MUTCD to safely separate construction activities from pedestrian traffic.

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Sequence work in phases (e.g., half-width closures, alternating sides) to ensure continuous access.

Provide non-slip temporary walking surfaces where existing walking paths are impacted.

Maintain safe lighting levels if work occurs during low-light conditions.

D. Protection of Infrastructure Below Bridge

The Contractor shall implement full overhead protection measures to prevent tools, debris, materials, or equipment from falling from the bridge onto underlying infrastructure, walkways, or sensitive areas.

Install debris containment systems including, but not limited to, toe boards, debris netting, scaffold sheeting, and catch platforms.

Secure all tools and materials at all times when working above grade using tethering systems or containment bins.

Prohibit loose material staging near bridge edges unless physically restrained.

Provide daily inspection of protection systems and immediately repair any deficiencies.

Immediately remove any fallen debris and report incidents to the COR.

Protect existing utilities, architectural features, and pedestrian areas below from damage due to falling or dropped materials.

Include these protection measures in the Contractor’s Specific Safety Plan (SSSP).

Period of Performance: 180 calendar days from the date of Notice to Proceed (NTP), inclusive of weather delays and administrative time.

ITEM 2 - EXISTING UTILITIES

2.1 Contractor shall coordinate utility locating with all park utility managers and Kentucky 811 prior to any concrete coring or substrate penetration.

2.2 Any damaged known or unknown utilities shall be reported immediately to the COR and restored at no cost to the Government.

2.3 No service interruptions shall be allowed without written authorization and scheduled temporary service provisions.

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ITEM 3 - CONTRACTOR’S USE OF PREMISES

3.1 Compliance

All work shall comply with Mammoth Cave National Park’s regulations, including noise limits, public safety, and protection of natural and cultural resources.

3.2 Work Hours

Monday through Friday, 8:00 AM to 5:00 PM. No work allowed on Federal holidays or weekends without prior approval.

3.3 Site Access and Staging:

Contractor access shall be limited to designated service routes shown in Appendix A.

Laydown and storage will occur in the designated parking lot staging area only.

All access beneath the bridge shall utilize equipment with PSI ratings under 5 to protect root zones and archaeological deposits.

3.4 Contractor is responsible for their own potable water, electricity, waste management, and sanitary facilities.

ITEM 4 - COMMENCEMENT, PROSECUTION, AND COMPLETION

4.1 Work Commencement

Work shall commence within 10 calendar days of NTP. Contractor shall provide a project schedule, including all phases and submittals, at the preconstruction conference.

ITEM 5 - EXAMINATION OF THE SITE

5.1 Site Visits

All bidders are required to visit the site. No change orders will be accepted for conditions reasonably observable during the site visit.

ITEM 6 - ABBREVIATIONS

6.1 Refer to the NPS Reference Standards including, but not limited to:

ASTM C928, C881, C171, C309, ACI 546R, ACI 364.1R, ANSI A118.4

OSHA 29 CFR 1926

NECA, NFPA 241, SMACNA, EPA Stormwater Guidelines

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ITEM 7 - ACCIDENT PREVENTION

7.1 Safety Plan

Submit a site-specific Accident Prevention Plan (APP) that includes:

Hazard identification and JHAs for concrete work, overhead work, and epoxy injection.

Emergency contact procedures and evacuation plan.

Weekly toolbox safety meetings.

All personnel must wear appropriate PPE: hard hats, safety glasses, gloves, and Class II safety vests.

ITEM 8 - PRECONSTRUCTION CONFERENCE

8.1 Pre-Construction

Contractor shall attend and provide all submittals: schedule, APP, submittal log, bonding documents, and list of subcontractors.

Contractor shall present plan to keep bridge open and accessible throughout the project life.

ITEM 9 - SUBMITTALS

9.1 Submit shop drawings and product data for:

Crack repair system

Mortar materials

Doweling epoxies

Sandstone veneer

Anchoring system

All materials must be reviewed and approved by the COR prior to use.

ITEM 10 - TEMPORARY SERVICES

10.1 Contractor shall provide temporary water and power connections (if needed), construction signage, fencing, and environmental protection systems (e.g., silt socks, catchment barriers).

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ITEM 11 - PROJECT CLOSEOUT

11.1 Contractor shall perform:

Final site cleaning

Submission of all warranty documents

Photo documentation (pre, progress, and final)

As-built drawings if deviations occur

COR will conduct a final inspection and issue acceptance within 10 business days of request.

Punch list must be completed within 30 calendar days.

PART 2 – EXECUTION

Execution Plan and Sequencing:

1. Mobilization & Environmental Protection:

o Deliver equipment to staging area.

o Install tree protection fencing and erosion control BMPs per EPA and NPDES standards.

2. Inspection & Surface Preparation:

o Sound concrete with chain drag.

o Mark delaminated zones and document defects.

o Scarify and clean surfaces (compressor or sandblaster).

3. Crack and Spall Repair:

o Inject epoxy per manufacturer’s method (pressure or gravity-fed).

o Patch voids with repair mortar.

o Moist cure as per ASTM C171 or equivalent wet cure method.

4. Beneath-Bridge Reinforcement:

o Scarify substructure face.

o Install formwork, rebar dowels, and pour concrete.

o Strip forms and allow full cure (minimum 7 days at 50°F or above).

5. Sandstone Veneer Installation:

o Clean cured surface.

o Install adhesive or mechanical anchors.

o Set veneer to match historical layout.

8 | P a g e o Mortar joints to match original profile.

6. Quality Assurance and Testing:

o Slump test concrete per ASTM C143.

o Compression test (ASTM C39) of poured concrete.

o Adhesion pull tests for veneer if requested by COR.

7. Final Walkthrough and Documentation:

o Submit warranties, photos, and inspection reports.

o Restore staging area and demobilize.

PART 3 – ATTACHMENTS

ITEM 1 – Location

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ITEM 2 – Pictures

2.1 - Picture of pedestrian bridge from Visitor Center perspective.

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2.2 - Picture of pedestrian bridge from the Visitor Center perspective #2

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2.3 – Picture of the end of the bridge as it transitions into the Visitor Center Back Porch

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2.4 - Picture of under-bridge foundation (Visitor Center side)

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2.5 - Picture of bridge transition (Hotel side facing WEST)

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2.6 - Picture of bridge transition (Hotel side facing EAST)