SPBN262013_B197 Overhang and Concrete Pad_RFP~1.pdf

DEPARTMENT OF THE AIR FORCE

102D INTELLIGENCE WING (ACC)

MASSACHUSETTS AIR NATIONAL GUARD

OTIS AIR NATIONAL GUARD BASE

REQUEST FOR PROPOSAL (RFP)

PROJECT: DESIGN AND CONSTRUCTION OF CONCRETE

PAD AND STRUCTURAL METAL OVERHANG

102d Civil Engineer Squadron — Otis ANGB, Joint Base Cape Cod, MA

1. Project Overview & Objective

The 102d Civil Engineer Squadron (CES) at Otis Air National Guard Base (ANGB) is soliciting proposals from qualified contractors to design and construct a durable, high-performance concrete pad and a structurally sound, all-metal overhead canopy/overhang.

The structure will be exposed to the harsh coastal, marine environment of Cape Cod. It must be engineered to withstand high wind uplift, freeze-thaw cycles, coastal snow loading, and highly corrosive salt-air conditions.

• Pad Footprint: 20 ft×20 ft (nominal)

• Overhang Coverage: 20 ft×20 ft (minimum footprint coverage)

• Location: Otis ANGB, Joint Base Cape Cod (JBCC), Massachusetts. Specifically located immediately behind Building 197, either structurally attached to the building or situated as a standalone structure within a short distance from the building's back door (subject to engineering design and field verification).

2. Technical Scope of Work

2.1 Site Preparation & Earthwork

• Excavation and Subgrade: Excavate the 20 ft×20 ft footprint to a depth compliant with local frost−depth regulations (minimum 3 ft below finished grade to prevent frost heave). Clear all organic material and loose soils. Contractor must field-verify and avoid any underground utility lines serving Building 197 prior to digging.

• Base Course: Install and compact a minimum 6 inch crushed gravel base (AASHTO M147 or equivalent) compacted to ≥95% modified proctor density.

2.2 Concrete Pad Specification (Salt-Air & Freeze-Thaw Resistance)

Due to Cape Cod's marine atmosphere and severe winters, the concrete mix must be engineered to resist chloride penetration and freeze-thaw cycles (corresponds to ACI 318 exposure categories C2 for corrosion and F3 for freeze-thaw):

• **Compressive Strength (fc′):∗∗Minimum$5000 psi at 28 days.

• **Water-to-Cementitious-Materials Ratio (w/cm):∗∗Maximum 0.40 to reduce permeability.

• Air Entrainment: 6.0%±1.5% to survive rapid freeze-thaw environments.

• Reinforcement: Grade 60 reinforcing rebar configured in a grid system. All rebar must be epoxy-coated or hot-dip galvanized to prevent internal corrosion from coastal humidity.

• Concrete Cover: Reinforcement must maintain a minimum concrete cover of 3 inches for concrete cast against and permanently exposed to earth.

• Drainage Slope & Interface: Concrete pad must be finished with a 1% to 2% (approximately 1/8 inch to 1/4 inch per foot) slope directing surface water away from both the concrete pad and the existing foundation of Building 197.

2.3 Metal Overhang and Structural Support

The canopy structure must provide overhead protection and be securely anchored to deep piers, integrated into the concrete pad foundations, or engineered to interface with Building 197. Wood or timber elements of any kind are strictly prohibited.

2.3.1 Building 197 Interface Options

Contractors may propose one of the following structural configurations:

• Option A (Attached Structure): The overhang is structurally anchored to the rear exterior wall/framing of Building 197. The contractor must supply calculations proving the existing wall structure can support the proposed wind, snow, and dead loads. High-durability flashing and industrial-grade marine sealants must be installed at the building interface to guarantee a watertight seal and prevent water intrusion behind Building 197's siding.

• Option B (Standalone Structure): The overhang is a fully self-supporting cantilever or four-post canopy built within close proximity (a short distance) of Building 197's back door. Post columns must be positioned to ensure they do not obstruct door clearance, paths of travel, or emergency egress routes.

2.3.2 Structural Metal Specifications

• Structural Framing System: Heavy-duty, high-durability structural metal framing.

Acceptable systems include:

o Hot-Dip Galvanized Structural Steel: Steel structural shapes and hollow structural sections (HSS) galvanized post-fabrication in accordance with ASTM A123 / A123M (minimum 2.0 oz/ft2 or 86 microns thickness).

o Marine-Grade Structural Aluminum: Structural aluminum components utilizing high-strength, corrosion-resistant alloys (e.g., 6061-T6), with clear anodized finishes (AAMA 611 Class I).

o Coated Carbon Steel: Factory-applied high-performance multi-coat epoxy primer and polyurethane topcoat system designed for ISO 12944 C5-M (Very High Marine) environments.

• Metal Roofing Deck/Panels: Heavy-gauge, minimum 24-gauge standing seam metal panels. Roof panels must be factory-coated with a PVDF fluoropolymer protective coating (Kynar 500 or Hylar 5000) or constructed of marine-grade aluminum to resist salt-air corrosion, blistering, and fading.

• Wind Load Design: The overhang must be engineered in accordance with ASCE 7 and local amendments. It must withstand an ultimate design wind speed (Vult) of 130 mph (Risk Category II or III depending on exact location proximity). Special attention must be paid to wind uplift force engineering on the roof panels and structural columns.

• Snow and Ice Design: The metal roof must support Cape Cod's ground snow load (pg =30 psf)plus additional safety factors for drifting and sliding snow. The roof slope must be design−optimized (minimum 3:12 pitch) to promote runoff.

• Corrosion Protection & Fasteners: All fasteners, connectors, structural anchors, concrete anchors, and tie-downs must be Grade 316 stainless steel or hot-dip galvanized steel conforming to ASTM A153 / A153M. Neoprene or EPDM washers must isolate dissimilar metals (e.g., steel fasteners on aluminum panels) to prevent galvanic corrosion.

2.4 Egress, Safety, and Door Clearance

• Egress Requirements: The structure, concrete pad, and vertical columns must maintain strict compliance with National Fire Protection Association (NFPA) 101 Life Safety Code and IBC egress regulations. The installation must not block, restrict, or decrease the clear opening width or head clearance of Building 197's back exit.

• Step/Threshold Interface: The top elevation of the concrete pad must be engineered to coordinate perfectly with the existing door threshold of Building 197 to avoid creating a trip hazard.

3. Applicable Codes, Standards & References

The contractor is responsible for ensuring all designs and construction tasks strictly adhere to the latest state and federal construction regulations.

• Massachusetts State Building Code (780 CMR): All design and construction must conform to the 10th Edition of the Massachusetts State Building Code (780 CMR).

This 10th Edition became effective on October 11, 2024, and is based on modified versions of the 2021 International Codes (including the 2021 IBC). The transition concurrency period allowing the use of the 9th Edition ends on June 30, 2025, after which the 10th Edition will be the exclusive code in effect. Refer to the official state handbook at: https://www.mass.gov/handbook/tenth-edition-of-the-ma-state-building-code-780

• Department of Defense Unified Facilities Criteria (UFC): The structure must meet Department of Defense physical planning guidelines, accessible via the main Whole Building Design Guide (WBDG) portal at: https://www.wbdg.org/ https://www.mass.gov/handbook/tenth-edition-of-the-ma-state-building-code-780 https://www.mass.gov/handbook/tenth-edition-of-the-ma-state-building-code-780 https://www.wbdg.org/

• DoD Structural Engineering Criteria: All structural calculation sheets must align with the current structural engineering mandates and wind/snow load parameters in UFC 3-301-01 (Structural Engineering). Refer to the official document page at:

https://www.wbdg.org/dod/ufc/ufc-3-301-01

4. Contractor Safety & Base Access Requirements

4.1 Force Protection & Base Access Procedures

The project is located within a secure military installation. The contractor must strictly adhere to all Joint Base Cape Cod (JBCC) security protocols.

• Vetting & Identification: All contractor and subcontractor personnel aged 18 or older must submit to criminal background checks (including NCIC vetting).

Personnel must carry a valid, unexpired government-issued photo ID (driver's license, passport, or Common Access Card) to enter the base.

• Primary Entrance: All personnel and commercial vehicles must enter the base through the main security gate located off Connery Avenue. Refer to the base overview guidelines at: https://www.massnationalguard.org/JBCC/jbcc-overview.html Detailed check-in steps and visitor center services are also listed at:

https://mybaseguide.com/joint-base-cape-cod-in-depth-welcome-center

• Vehicle Requirements: Commercial vehicles, including concrete mixers and delivery trucks, are subject to 100% inspection upon each entry. Drivers must present a valid driver's license, current state vehicle registration, and active commercial vehicle insurance.

• Escort Procedures: Un-vetted individuals or delivery services without prior approval will be denied entry. Contractors cannot escort unauthorized personnel onto the base.

4.2 On-Site Safety

• OSHA & USACE Standards: The contractor must comply with OSHA construction safety standards (29 CFR 1926).

• Personal Protective Equipment (PPE): All workers must wear appropriate PPE, including hard hats, high-visibility vests, safety glasses, and steel-toe boots at all times while on the construction site.

https://www.wbdg.org/dod/ufc/ufc-3-301-01 https://www.massnationalguard.org/JBCC/jbcc-overview.html https://www.massnationalguard.org/JBCC/jbcc-overview.html https://mybaseguide.com/joint-base-cape-cod-in-depth-welcome-center

2.4 Egress, Safety, and Door Clearance

5. Proposal Submission Guidelines