# Introduction

This statement of work describes the activities required to install an
antenna tower at the Liberty Research Center (LRC), a U.S. government
facility located at 7301 Ridge Road, Marriottsville, MD 21104-1130, in
Carroll County. The purpose of the tower is to house a 24 ft radome,
antenna system and shelter. The tower will be high enough to allow the
antenna to operate above the tree lines to eliminate any obscurations
caused by current trees residing on County property. According to County
regulations, we are unable to top the trees. The Contractor shall
provide the design, labor and materials for the installation of an
antenna tower at the LRC. The erected tower shall be designed in
coordination with the Army Corp of Engineers. The contractor shall gain
permission to enter and work at the LRC in accordance with their
regulations.

A subsurface soil exploration was performed at the location where the
antenna tower is to be installed on 22 February 2006. The Geotechnical
Report dated on 7 March 2006 is provided herein. This test report is
based on borings drilled on 22 February 2006.

A Site Survey will be conducted prior to submission of bids.

# Technical Tasks

The Contractor shall provide all necessary Architect-Engineer services
by qualified Architect-Engineers licensed in the State of Maryland as
required to design and prepare complete construction documents, i.e.,
specifications (as required), detailed construction drawings, budgetary
construction cost estimates, and as-built final construction documents.
The Contractor shall design and erect an antenna tower that will house a
government provided radome and shelter with the following specifications
(a concept drawing is provided) in accordance with the Building
Officials and Code Administrators International Code (BOCA), the
International Conference of Building Officials (ICBO) Code, Carroll
County Code and Building Regulations and the Army Corps of Engineers
Safety Manual: EM 385-1-1. Where regulations or guidance conflicts, the
**MOST STRINGENT REQUIREMENT WILL PREVAIL**.

.

1.  The Contractor shall erect a 36 ft high antenna tower on a
    foundation designed in accordance with construction best practices
    based on the subsurface soil exploration test report and loads
    indicated below.

2.  The antenna tower shall have three levels, with the top level
    holding the radome.

3.  The contractor shall provide a concrete slab at ground level. The
    concrete slab shall cover the ground under the tower and surround
    each support leg and be able to accommodate the weight of two 4 ton
    pickup trucks.

4.  All concrete shall be field tested to determine slump and
    compressive strength. The contractor shall take concrete samples
    during concrete placement.

    a.  Slump tests shall be performed in accordance with ASTM C143-90,
        *Standard Test Method for Slump of Hydraulic Cement Concrete*.
        The maximum slump shall be 5 inches, but may be increased with
        the addition of an approved admixture provided that the design
        water-cement ratio is not exceeded. Perform tests at
        commencement of concrete placement, when test cylinders are made
        and for each batch (minimum) or every 20 cubic yards (maximum)
        of concrete. Concrete not meeting the maximum slump requirements
        will be rejected by the Technical POC.

    b.  Compressive strength testing shall be in accordance with ASTM
        C39, *Standard Test Method for Compressive Strength of
        Cylindrical Concrete Specimens*. The contractor shall take five
        test cylinders for each set of compressive strength tests.
        Precautions shall be taken to prevent excessive evaporation and
        loss of water from the specimen. Two cylinders for each test set
        shall be tested at 7 days, two cylinders at 28 days and one
        cylinder held in reserve. Samples for strength tests shall be
        taken for each truck. Each strength test result shall be the
        average of the two cylinders from the same concrete sample
        tested at 28 days. The contractor shall provide the Technical
        POC with the test results within 1 day of receiving them.
        Concrete not meeting the design specified compressive strength
        criteria shall be removed and replaced with new acceptable
        concrete.

5.  The Contractor shall provide the tower with three levels. The first
    level shall be 12 ft above the concrete slab. This is identified as
    Level 1 on the concept drawing. Level 2, as identified on the
    drawing, shall be 24 ft above the concrete slab and shall support
    the electronic equipment shelter. Level 3, as shown on the drawing,
    shall be the top of the tower, 36 ft above the concrete slab and
    shall support the radome. Safety railings and access stairs shall be
    in accordance with Occupational Safety & Health Administration
    (OSHA) regulations.

6.  The tower structural beams shall be constructed of hot-dipped
    galvanized steel. All levels of the tower shall be a minimum of 24
    ft x 24 ft.

7.  The Contractor shall provide a tower capable of housing a 24 ft
    diameter radome, antenna system and a 24 thousand pound (24,000 lb)
    electronic shelter. The shelter exterior dimensions are 20 ft x 8 ft
    x 8 ft. The shelter shall be placed on Level 2 directly beneath the
    radome. The maximum weights of the individual units are: Shelter -
    24,000 pounds, Antenna System -- 3,000 pounds; Radome -- 2,500
    pounds; HVAC system -1,500 pounds for a total equipment weight of
    31,000 pounds. The HVAC system will be placed on Level 1. The
    Contractor shall design the structure to hold up to 10 personnel
    performing maintenance and another 4,000 pounds of maintenance
    equipment. The shelter, antenna, radome and HVAC are provided by the
    government. The Contractor shall place the antenna on Level 3 and
    the shelter on Level 2 of the tower. The government will fasten both
    the antenna and shelter after it is determined that both can be
    fastened to the tower as required. The government will be
    responsible for the placement of the HVAC equipment and the radome.

8.  The Contractor shall provide Levels 1, 2 & 3 walking surfaces as
    follows:

-   Level 1: Surface should be an open grate suitable for walking which
    allows water to pass without puddling.

-   Level 2: Surface should be an open grate suitable for walking which
    allows water to pass without puddling. Level 2 shall accommodate
    access to cable entry ports in the shelter labeled P1 and P2 in the
    drawing labeled \"APS Floor Entry Panels\". Panels P1 and P2 are on
    the bottom of the shelter for signal interface cables from an
    existing building. Power entry panel labeled P4 in the drawing
    labeled \"Exterior End Views\" and antenna interface port P6 on top
    of the shelter in drawing labeled \"APS 100-002 Exterior Top View of
    the shelter\" must also have unlimited access.

-   Level 3: Surface shall be weather tight to allow for heating/air
    conditioning of the radome and suitable for walking.

9.  A ladder or steps shall be installed on the area behind the shelter
    to give access from the floor of Level 2 to the floor of Level 3
    into the radome. The contractor shall provide a lockable hatch at
    Level 3 to block access to the radome.

10. The tower wind loading requirement, with the radome considered, is
    for 150 mph gusts. The ice loading requirement is as required for
    local conditions.

11. The tower shall be installed within an existing fenced compound. The
    contractor shall provide approximately four feet (4 ft) wide strip
    of gravel, 4 in deep, between the concrete slab and the existing
    fence on two sides of the concrete slab. The contractor shall
    provide for weed control under the gravel.

12. The Contractor shall provide a lighting ground ring around the tower
    approximately three (3) feet out from the base. This ground ring
    shall consist of \# 4/0 AWG bare copper wire with ground rods
    installed at each base corner, below grade. Each leg of the tower
    shall be grounded to this ground ring by use of Cadweld/Exothermic
    weld. The contractor shall install the lighting ground so that the
    tower ground shall be separate from existing site grounding systems

13. The Contractor shall install two (2) PVC conduit runs of two (2)
    inch minimal size below grade from the tower base to the exterior of
    the existing building to allow for government installation of
    electrical power. The approximate length is 90 ft.

14. The Contractor shall install one (1) PVC conduit run of three (3)
    inch minimal size below grade from the tower base to the existing
    exterior of building to allow for government installation of signal
    cables. The approximate length is 90 ft.

15. The Contractor shall return the site grounds to the condition as
    found prior to the stated work.

The regulations and building codes cited previously need to be addressed
and met as required.   The contractor is fully responsible for designing
the tower to meet those regulations and building codes. NRL will have
the Liberty Research Center\'s Army Corp of Engineers POC, at the site
for the site visit and he will be available during the design and
construction process to answer your questions as will be the NRL
Technical POC and site representative.

**3. Drawings**

The contractor shall submit design drawings of the tower, foundation
base and levels for government approval prior to installation. These
design drawings shall be submitted in the format required by Carroll
County Code in order to obtain building permits and shall be stamped
with professional seals. The contractor shall provide all design
calculations e.g. loads, stresses, etc.

The contractor shall provide two sets of As-Built Drawings within two
business days after construction is completed.

**4. Construction Permits**

The contractor shall be responsible for:

1.  obtaining proper zoning or other land use control approval for the
    project

2.  paying any fees due for the foregoing, and

3.  obtaining and paying for any building permits.

The Army Corps of Engineers will issue a permit to NRL to permit the
construction of the tower at Liberty Research Center, which is leased by
the Corps from the City of Baltimore.

**5. Project Manager and Points of Contact**

Project Manager for this contract is Mrs. Windie Borodin, Director of
the Midway Research Center; phone 703-551-1992

Technical POC at the site is Todd Miller, 202-279-7202, cell
202-437-2970.

Site POC is Elza Redman, 410-781-0487, cell 410-207-7233.

Army Corps of Engineers POC is Clayton Redmond, 443-479-5671.

**6. Schedule**

All design work, drawings and design calculations shall be completed and
provided for government approval under CLIN #0001 within 45 days after
contract award.

After all governmental approvals have been completed the government will
authorize construction under CLIN #0002. All construction shall be
completed within 90 days after exercise of CLIN #0002.

**7. Proposal**

The contractor shall include the following with the proposal:

1.  a schedule,

2.  preliminary design drawings, and

3.  preliminary design calculations.