4_22_26_MACA_337611A_SOW_0003.pdf

1 | P a g e

Mammoth Cave National Park

STATEMENT OF WORK

Cosmetic Repair of Pedestrian Bridge Foundation

PMIS# 337611

DATED: 11/24/2025

NATIONAL PARK SERVICE

SOUTHEAST REGION

2 | P a g e

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 of all vertical and horizontal concrete surfaces.

• Mark all delaminated areas, shrinkage cracks, and spalls.

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

• For cracks >1/16” and spalls:

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

◦ Apply epoxy bonding agent to prepared area.

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

◦ Finish flush with adjacent concrete.

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

3 | P a g e

B. Substructure Repairs Beneath Bridge Span (Approx. 100 SF)

• Mechanically scarify designated substructure zones to 1/4”–3/8” depth using chipping hammer per ICRI Guideline No. 310.2R.

• Install modular formwork for vertical faces.

• Drill and install #4 epoxy-coated dowels into sound substrate at 12” O.C. using epoxy anchoring system conforming to ASTM C881.

• Place 0.5 CY of high-strength (5,000 psi at 28 days), low-shrink concrete.

• Consolidate with internal vibrator; allow to cure for a minimum of 7 days.

C. Adhered Stone Veneer System

All stone finish work shall be an adhered sandstone veneer system installed over a prepared cast-in-place concrete substrate. The veneer shall be non-load bearing.

C.1 Substrate Construction (Structural Backing):

• Surface preparation shall achieve a Concrete Surface Profile (CSP) of 5 to 7, defined as a medium to heavy roughened surface with exposed aggregate, produced by mechanical scarification or chipping, in accordance with ICRI Guideline 310.2R

• Contractor shall drill, clean, and install #4 epoxy-coated reinforcing dowels into existing bridge concrete to mechanically bond new concrete work. Dowels shall be installed at 12 inches on-center each way in a uniform grid pattern.

• Holes shall be drilled to the depth required by the adhesive manufacturer and thoroughly cleaned using a blow–brush–blow method (compressed air, wire brush, compressed air) to remove all dust and debris prior to adhesive placement.

• Dowels shall be set using a structural epoxy adhesive conforming to ASTM C881, Type IV, Grade 3, ensuring complete encapsulation of the bar and full bond between existing and new concrete.

• Install reinforcement as required to support veneer (minimum 4" thick backing).

• Place cast-in-place concrete (4,000 psi at 28 days per ASTM C39; mix per ASTM C94/ACI 211).

◦ If concrete break tests reveal proper break-strength (defined as 4,000 psi), by day 7, contractor is approved to continue construction.

• Consolidate with internal vibration (ACI 309) and cure per ACI 308 (min. 7 days or approved curing compound ASTM C309). Vibrate the concrete so there are no voids and it bonds tightly to the existing structure

• Keep the concrete wet and protected so it cures strong and doesn’t crack.

• Form faces to receive adhered veneer; provide plane tolerance of ±1/8" in 10 ft.

Commented [CP1]: Answer to RFI #1

4 | P a g e

C.2 Surface Preparation for Veneer:

• After curing, clean substrate to remove laitance, dust, and contaminants (pressure wash or abrasive blast as needed).

• Verify surface soundness and moisture per manufacturer requirements.

C.3 Veneer Materials:

• Natural sandstone veneer units, 3"–5" nominal thickness, color/texture to match adjacent.

• Use a high-strength adhesive mortar designed for exterior stone installation that provides strong bonding, flexibility, and resistance to moisture and temperature changes. Polymer-modified thin-set mortar meeting ANSI A118.4/A118.15 shall be used.

• Mortar for joints: Type S per ASTM C270 (or manufacturer system compatible with adhered veneer).

C.4 Installation (Adhered Veneer):

• Prior to applying mortar, the concrete surface shall be pre-wetted and allowed to reach a saturated surface dry (SSD) condition, meaning the surface is damp with no standing water, unless manufacturer requires otherwise.

• Apply scratch/bond coat where required; comb thin set with appropriate notch.

• Set stones with full contact (≥95% coverage for exterior vertical), “back buttering” each unit.

• Maintain coursed pattern to match existing; control joint alignment with adjacent features.

• Joint width: 1/2"–1" unless otherwise approved; tool joints to match existing profile (concave or flush as directed).

• Provide temporary support/shoring as needed until initial set is achieved.

• Protect from rapid drying, freezing, and precipitation; cure per manufacturer.

C.5 Terminations and Transitions:

• Terminate veneer flush with adjacent architectural elements unless noted.

• Where existing caps occur, match profile and finish; submit details for approval.

• Seal the top edges of all stone veneer installations with a flexible, waterproof sealant to prevent water from getting behind the stone (compatible sealant per ASTM C920).

C.6 Sealer:

• Apply penetrating silane/siloxane sealer (≥40% silane), breathable, non-film forming, compliant with NCHRP 244 after full cure of mortar.

5 | P a g e

C.7 Quality Control:

• Perform adhesion checks per manufacturer; correct any hollow-sounding units.

• Tolerance: plane ±1/4" in 10 ft; alignment true to layout lines.

C.8 Submittals (for COR approval prior to procurement/installation):

• Product Data: stone source, physical properties, thin-set, mortar, dowel adhesive, sealant, and sealer.

• Shop Drawings: elevations, coursing pattern, jointing, terminations, interface details.

• Mix designs: concrete (ACI 211), mortar (ASTM C270).

• Concrete break tests

• Installation plan including sequencing, curing, and protection methods.

• Safety/APP sections specific to overhead work and debris containment.

C.9 Samples and Mockup (Mandatory):

• Stone Samples: Provide a minimum of three (3) sets of representative sandstone samples (min. 6" x 6" each) showing color and texture range for COR selection.

• Mortar Samples: Provide color samples for joint mortar (minimum two options).

• Mockup: Construct an on-site 3'-0" x 2'-0" (min.) adhered veneer mockup including substrate, thin-set, stone units, and tooled joints, reflecting final pattern and workmanship.

◦ Locate mockup where directed by COR.

◦ Obtain written approval prior to proceeding with production work.

◦ Approved mockup shall serve as the quality standard for the project and may remain in place if acceptable.

D. Limestone Cap Installation (Top of Piers/Columns)

• Provide and install two (2) custom-fabricated limestone caps at the designated pier locations.

• Caps shall be natural limestone, snapped/chiseled finish on exposed faces, nominal 3" thickness, with a pyramidal (hipped) profile sloping from edges to a centered high point to shed water.

• Plan dimensions shall be field-verified to match the receiving pier/column footprint; provide uniform overhang (approx. 1"–2") beyond veneer faces unless otherwise directed.

• Match the profile, color, texture, and finish of limestone caps being installed on adjacent project columns.

Commented [CP2]: Answer to #2

6 | P a g e

D.1 Materials:

• Limestone units: sound, durable, free of cracks/defects; color range consistent with adjacent approved samples.

• Setting mortar: Type S per ASTM C270 or manufacturer-approved setting bed compatible with limestone.

• Adhesive (if used): polymer-modified mortar per ANSI A118.4/A118.15.

• Sealant at joints: elastomeric sealant per ASTM C920, color to match mortar/stone.

D.2 Installation:

• Verify substrate is level and true; correct as required.

• Provide full bearing bed (≥95% contact) using mortar setting bed; avoid voids.

• Set caps plumb, level, and centered; maintain consistent overhang.

• Tool joints tight and smooth; seal perimeter joints to prevent water infiltration.

• Protect from movement and weather until set; cure per manufacturer.

D.3 Submittals and Samples (Required):

• Product data and quarry/source information for limestone.

• Stone samples: minimum two (2) representative samples (min. 6" x 6") showing color/texture range for COR selection.

• Shop drawings showing cap dimensions, overhang, and pyramidal profile geometry. Limestone cap shop drawings can be hand drawn but must specify dimensions.

• No mockup required.

D.4 Quality:

• Installed caps shall align with adjacent work; tolerance ±1/8" in 10 ft.

• Replace units with cracks, chips, or unacceptable color variation.

D. 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.

7 | P a g e

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

• 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.

E. 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 in accordance with OSHA 29 CFR 1926 Subpart L and Subpart M.

• 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 Accident Prevention Plan (APP) and Job Hazard Analysis (JHA).

F. Quoter Certification (Required)

The Quoter acknowledges the period of performance and agrees to complete all work required by the Statement of Work within 180 calendar days from the date of Notice to Proceed.

The Quoter further acknowledges and agrees to the following mandatory project requirements:

• Continuous Pedestrian Access: The pedestrian bridge shall remain open and accessible to the public for the duration of the project. The Contractor shall maintain a safe, unobstructed walkway in compliance with ABA/ADA requirements and implement phased construction, barriers, and signage as required.

• Protection of Infrastructure Below: The Contractor shall ensure that all tools, materials, and equipment are secured and protected at all times to prevent falling or displacement from the bridge onto the infrastructure, walkways, or areas below. Appropriate containment systems

8 | P a g e

(e.g., debris netting, toe boards, tethering) shall be installed and maintained in accordance with

OSHA 29 CFR 1926.

No full application shall proceed until written COR approval is received.

Period of Performance: 180 calendar days from Notice to Proceed (NTP), including all mobilization, staging, execution, curing, inspections, and demobilization.

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.

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.

9 | P a g e

ITEM 5 - EXAMINATION OF THE SITE

5.1 Site Visits

All bidders are encouraged to attend the site visit. 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

ITEM 7 - ACCIDENT PREVENTION

7.1 Safety Plan

Submit a site-specific Accident Prevention Plan (SSSP) 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, SSSP, 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

• All submittals shall be transmitted electronically using the NPS CM-16 Transmittal Form.

• Submittals shall be emailed to the Contracting Officer (CO) and COR.

• Submittals must be received as soon as reasonably possible.

9.1 Required Submittals

A. Administrative Submittals

10 | P a g e

Project Schedule (CPM or equivalent) Submittal Log Site-Specific Safety Plan (SSSP) List of Subcontractors Equipment Access and Loading Plan (including bridge loading calculations)

B. Concrete Repair and Structural Work

Polymer-modified repair mortar product data Concrete mix design:

o 4,000–5,000 psi mix Concrete testing plan:

o Slump

C. Adhered Stone Veneer System

Product data for:

o Sandstone veneer (source, physical properties) o Thin-set mortar o Joint mortar o Sealant

Shop Drawings:

o Coursing pattern o Joint layout o Terminations and transitions

D. Limestone Cap System

Product data (quarry/source) Shop drawings (can be hand-drawn) including:

o Dimensions o Overhang o Pyramidal (hipped) profile

Setting materials:

o Mortar / adhesive data

F. Samples (Physical Submittals)

Stone Veneer Samples Minimum three (3) sets Show full color/texture range

Mortar Samples Minimum two (2) color options Include joint finish type

Limestone Cap Samples Minimum two (2) samples Show finish (snapped/chiseled) and color range

G. Mockups

11 | P a g e

Adhered veneer mockup o Minimum 3'-0" x 2'-0" o Full system:

Substrate Thin-set Stone Joints

Mockup can be created using plywood back board Mockup becomes quality standard

H. Field Testing Submittals

Contractor to apply crack repair materials to discrete location for verification by COR Approval can be given on-site by COR, as long as digital documentation follows Documentation of:

o Locations (hidden areas) o Products used o Application method

Post-application evaluation report (optional but recommended)

I. Means and Methods Submittals

Bridge access plan Fall protection plan (overhead work) Debris containment plan Pedestrian access maintenance plan

J. Quality Control Submittals

Concrete test reports (break tests) Adhesion verification (veneer)

K. Closeout Submittals

Warranty documentation Product data (as-built record set) Photo documentation:

o Pre-construction o Progress o Final

As-built drawings (if deviations occur)

9.2 Approval Requirements

• No material, system, or product requiring submittal shall be installed prior to written approval by the COR.

• Any work performed without approved submittals shall be subject to removal and replacement at no cost to the Government.

Commented [CP3]: Answer to RFI #5

12 | P a g e

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).

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, Access, and Protection

Mobilize personnel, materials, and equipment to designated staging areas.

Install erosion control and environmental protection measures per EPA and NPDES requirements.

Install overhead protection systems (debris netting, toe boards, catch platforms) beneath all work areas.

Implement approved pedestrian access plan, maintaining minimum 48-inch clear walkway.

Provide traffic control, barriers, and signage per OSHA 29 CFR 1926 and MUTCD.

Mobilize and position:

o Articulating boom lift and/or bucket truck for access to crack repair areas.

2. Pre-Repair Inspection and Documentation

Perform detailed visual inspection and acoustic sounding (chain drag/hammer) of all concrete surfaces.

Identify and mark:

o Cracks (hairline and structural) o Spalls and delaminations

Document all repair areas with photographs and field notes.

Submit documentation to COR for review prior to initiating repairs.

3. Localized Surface Preparation

Perform localized surface preparation only at repair areas.

Cleaning methods shall include:

o Oil-free compressed air o Wire brushing o Light mechanical abrasion as required

Commented [CP4]: Answer to RFI #3

13 | P a g e

Remove all dust, debris, laitance, and unsound material.

All debris shall be contained and removed daily; no material shall fall below the bridge.

4. Crack Repair Operations

4.1 General

Access crack locations using approved lift equipment.

Perform all work in accordance with manufacturer recommendations and approved submittals.

4.2 Crack Preparation

Clean cracks using compressed air and mechanical methods.

Install injection ports where required.

Seal surface of cracks with epoxy paste for injection control (if applicable).

4.3 Crack Injection

Hairline Cracks (<1/16”):

o Repair using low-viscosity epoxy (ASTM C881 Type I or II).

o Apply via gravity feed or low-pressure injection.

Structural Cracks (>1/16”):

o Repair using pressure injection system.

o Inject epoxy (ASTM C881 Type IV, Grade 3) until refusal.

o Ensure full penetration of crack depth.

4.4 Field Testing and Approval

Perform test repairs in COR-approved locations prior to full production.

Demonstrate:

o Injection method o Material performance o Surface finish

No production crack repair shall proceed without COR approval.

4.5 Finishing and Curing

Remove excess epoxy and patch materials.

Grind and smooth repaired areas to match adjacent concrete.

Protect repairs during curing period per manufacturer requirements.

5. Spall Repair

Remove unsound concrete to minimum depth of 1.5 inches with square edges.

Clean and prepare substrate.

Apply bonding agent.

Install polymer-modified repair mortar (ASTM C928).

Finish flush with adjacent surfaces.

Cure per ACI 308 using wet curing methods for minimum 72 hours.

6. Beneath-Bridge Structural Concrete Work

Scarify designated substructure areas to required depth (1/4”–3/8”) per ICRI 310.2R.

Drill, clean, and install reinforcing dowels:

o #4 epoxy-coated

Commented [CP5]: Answer to RFI #4

14 | P a g e o 12” O.C. each way o Installed using ASTM C881 adhesive

Install formwork and reinforcement.

Place cast-in-place concrete:

o Minimum 4,000–5,000 psi

Consolidate using internal vibration per ACI 309.

Cure per ACI 308 for minimum 7 days.

Verify concrete strength prior to proceeding with veneer installation.

7. Adhered Stone Veneer Installation

Prepare cured concrete substrate:

o Clean and verify soundness o Pre-wet to SSD condition

Install veneer using:

o Polymer-modified thin-set mortar (ANSI A118.4/A118.15)

Back-butter all stone units to achieve minimum 95% coverage.

Install in approved pattern and alignment.

Maintain joint spacing (1/2”–1”) and tool joints to match existing.

Provide temporary support as required.

Protect installation from environmental exposure during curing.

8. Veneer Terminations and Sealant

Seal all top terminations and transitions using ASTM C920 elastomeric sealant.

Ensure complete waterproofing at all exposed edges.

9. Limestone Cap Installation

Verify dimensions of receiving surfaces.

Install limestone caps:

o Full bearing (≥95% contact) o Proper alignment and overhang

Match adjacent project caps in profile and finish.

Seal all joints to prevent water intrusion.

Protect during curing.

10. Quality Control and Testing

Perform and document:

o Concrete slump tests (ASTM C143) o Compression tests (ASTM C39)

Inspect and verify:

o Crack repair effectiveness o Dowel installation o Surface preparation o Veneer adhesion and alignment

Correct all deficiencies immediately.

15 | P a g e

COR reserves the right to require additional testing.

11. Final Cleaning and Closeout

Remove all debris, materials, and temporary protections.

Restore staging and access areas to original condition.

Submit:

o Photo documentation (pre, during, post) o Warranty documentation o As-built drawings (if applicable)

Request final inspection.

Complete punch list items within required timeframe.

PART 3 – ATTACHMENTS

ITEM 1 – Location

16 | P a g e

ITEM 2 – Pictures

2.1 - Picture of pedestrian bridge from Visitor Center perspective.

17 | P a g e

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

18 | P a g e

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

19 | P a g e

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

20 | P a g e

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

21 | P a g e

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