Concrete - SOW.docx

CONCRETE CULVERT RETROFIT

STATEMENT OF WORK

1.0 LOCATION

Work will be performed at Fort AP Hill in Bowling Green, VA. Work crews will be granted access to the jobsite, but will require escort which will be provided by NSWC IHEODTD personnel.

2.0 STATUS OF EXISTING STRUCTURE

NSWC IHEODTD has a requirement to construct two (2) concrete structures using an existing on-site concrete culvert. The on-site structure is (shown in the images below) contains 13 concrete sections each designed to weigh close to 40,000lbs.

Figure 1: Pictures of Existing Concrete Structure

Although there are 13 concrete sections in the structure, there are only five (5) different concrete section types. Section “E” will not be used in this effort and will be relocated to the side of the test pad (roughly 100ft). One of the “D” sections is damaged and will need to be replaced with a new section.

Figure 2: Drawing of Existing Structure with Section Labels

Figure 3: Drawing of Existing Structure with Lap Joint Detail (the center section E is female on both ends)

The concrete culvert sections contain 6 inch lap joints and are held together using 2 inch diameter threaded rod in each of the four corners of the structure. The threaded rod was assembled in 6 foot sections with coupling nuts between the sections.

Figure 4: Picture of Threaded Rod Assembly at the Four Corners of the Structure

Four (4) lifting inserts are located at the top of each concrete section. NSWC IHEODTD will provide clutches to the Contractor for lifting.

3.0 PURPOSE

The existing structure will be reassembled, along with new parts, to create two (2) smaller structures (referred to as a “Window Test Unit” and a “Door Test Unit”) at the same site. The new structures will rest on the gravel bed that the existing structure currently sits.

Figure 5: Finished Site Layout

4.0 SCOPE

The Contractor shall perform the below tasks:

4.1 Disassemble the existing structure.

4.2 Cast one (1) new “D” section. One of the “D” sections in the existing structure was damaged and is no longer in usable condition. In order to construct the new test units, one (1) new “D” section must be cast.

Figure 6: Drawing of Section “D”

4.3 Relocate two (2) sections to the side of the test pad (~100ft). Section “E” will not be needed in the new setup and will be relocated to the side of the test pad. One of the “D” sections was damaged beyond repair and will be relocated to the side of the test pad.

Figure 7: Center section “E” and damaged section “D” will not be reused

4.4 Cast new front face end caps. In order to build the new structures, the Contractor will need to cast new front face end caps. The Contractor shall submit drawings for the new end caps in accordance with CDRL A001. These drawings will need to be approved by NSWC IHEODTD prior to casting.

After end cap drawings have been approved, the Contractor shall pour two (2) new end caps for the front face of the two (2) structures using 5000psi concrete. The new end caps will contain #4 rebar 10” on center, each way, each face. All new concrete sections should contain lifting inserts (4x Meadow Burke DB-52, 8-ton x13” dog bone anchors with recess) at the top of the section/end cap. There will be:

· One (1) end cap with double (2) doorways

· End cap will have female lap joint to mate with existing “D” sections.

· Doorways will contain a 3/8” thick channel embed with temporary supports which to keep the doorways square. Two (2) rows of nelson studs 6 inch O.C. will be used to secure the channel to the concrete. The channel will be on all sides of the door openings (top, sides, and bottom).

· One (1) end cap with double (2) window openings (4ft by 6ft openings)

· End cap will have female lap joint to mate with existing “D” sections.

· Windows will contain a 3/8” thick channel embed with temporary supports which will keep the windows square. Two (2) rows of nelson studs 6 inch O.C. will be used to secure the channel to the concrete. The channel will be on all sides of the window openings (top, sides, and bottom).

Both end caps will be 20 inches thick, but will be larger in outer dimensions than that of the rest of the structure. The front face dimensions of the new end caps will be 19’4” wide by 13’6” high. Even though the end caps will be larger than the rest of the structure, they will still be required to mate with section “D” from the existing structure. The new front face end caps must a female lap joint which mates with section “D”.

Figure 8: Dimensions of Front Face End Caps (dimensions in inches)

Pressure gauge inserts will be located on the new front face end caps. The gauge inserts simply allow a pressure gauge to be installed in the concrete wall outer surface by providing a channel for the gauge wire. Locations are shown in the below drawing. NSWC IHEODTD will provide the gauge inserts to the concrete caster.

Figure 9: Pressure gauge insert locations on the new front face end caps

Figure 10: Pressure gauge insert

4.5 Contractor shall locate all new material to the site.

The sections of each structure will be secured together using 2” threaded rod in the four corners of the structures (similar to the existing structure – see Figure 4). Threaded rod from the existing structure can be reused for this purpose. The Contractor shall provide new threaded rod as necessary. The Contractor be prepared with at least eight (8) 6 foot sections of threaded rod and coupling nuts.

The required hardware will include:

· 1 - new concrete section “D”

· 1 - new window front face end cap

· 1 - new door front face end cap

· 8 – 2” diameter threaded rod – 6 feet in length

· 8 – coupling nuts for threaded rod

· 8 – steel plate washer (8”x8”x1” thick) with 2.125” hole

· 1”x1” – closed foam gasket material and glue (positioned between the concrete culvert sections)

4.6 Construct two (2) test units. Two (2) new test structures will be constructed. One of the units will have two (2) door openings on the front face. The other unit will have two (2) window openings on the front face. Sections “D”, “C”, “B”, and “A” from the existing structure will be reused. All of the existing sections have four (4) 8-ton lifting inserts embedded on the top of the concrete.

New Test Unit Concept Drawing

The test units will be assembled on the existing gravel bed located at the test site. The test units will be angled slightly to face a central reference location.

Location of new test units

5.0 Deliverables.

5.1 Engineering drawing for concrete structure (CDRL A001).

DESTRUCTION NOTICE: Destroy by any method that will prevent disclosure of contents or reconstruction of the document.

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