**Construction Specification 781---Metal Fabrication and Installation**

**1. Scope**

The work consists of furnishing, fabricating, and erecting metalwork,
including the metal parts and fasteners of the composite structures.

**2. Material**

Steel shall be structural quality according to ASTM A 36 unless
otherwise specified. Castings shall be thoroughly cleaned and subjected
to careful inspection before installation. Finished surfaces shall be
smooth and true to assure proper fit. Galvanizing shall conform to the
requirements of ASTM A 123.

**3. Fabrication**

Fabrication of structural steel shall conform to the requirements of
Specification for the Design, Fabrication and Erection of Structural
Steel for Buildings (Riveted, Bolted and Arc-Welded Construction),
American Institute of Steel Construction.

**4. Erection**

The frame of metal structures shall be installed true and plumb.
Temporary bracing shall be placed wherever necessary to resist all loads
to which the structure may be subjected, including those applied by the
installation and operation of equipment. Such bracing shall be left in
place as long as may be necessary for safety.

As erection progresses the work shall be securely bolted up, or welded,
to resist all dead load, wind, and erection stresses. The contractor
shall furnish such installation assisting bolts, nuts, and washers as
may be required.

No riveting or welding shall be performed until the structure is
stiffened and properly aligned.

Rivets driven in the field shall be heated and driven with the same care
as those driven in the shop.

All field welding shall be performed in conformance to the requirements
for shop fabrication except those that expressly apply to shop
conditions only.

**5. Protective coatings**

Items specified to be galvanized shall be completely fabricated for
field assembly before the application of the zinc coatings. Galvanized
items shall not be cut, welded, or drilled after the zinc coating is
applied.

Items specified to be painted shall be painted in conformance to the
requirements of multiple coat system 2 as found in latest edition of the
Alabama Department of Transportation\'s, \"Materials, Sources, and
Devices with Special Acceptance Requirements\" manual, List III-1.

**6. Measurement and payment**

***Method 1---***The work is not measured. Payment for metal fabrication
and installation is made at the contract lump sum price in the contract.
Such payment constitutes full compensation for all labor, equipment,
material, and all other items necessary and incidental to the completion
of the work including connectors and appurtenances, such as rivets,
bolts, nuts, pins, studs, washers, hangers, and weld metal.

***Method 2---***The weight of metal installed complete in place shall
be determined to the nearest pound. Unless otherwise specified, the
weight of metal shall be computed by the method specified in section 3
of the Code of Standard Practice for Steel Buildings and Bridges,
American Institute of Steel Construction, except that the following unit
weights shall also be used, as appropriate, as the basis of computation:

> Material Unit weight\
> (lb/ft3)
>
> Aluminum alloy 173
>
> Bronze or copper alloy 536
>
> Iron, malleable 470
>
> Iron, wrought 487

Payment for furnishing, fabricating, and installing metalwork is made at
the contract unit price for the specified types of labor, material,
equipment, and all other items necessary and incidental to the
completion of the work.

***Method 3---***The work is not measured. Payment for furnishing,
fabricating, and installing each item of metalwork is made at the
contract price for that item. Such payment constitutes full compensation
for all labor, equipment, material, and all other items necessary and
incidental to the completion of the work including connectors and
appurtenances, such as rivets, bolts, nuts, pins, studs, washers,
hangers, and weld metal.

***All methods---***The following provisions apply to all methods of
measurement and payment. Compensation for any item of work described in
the contract, but not listed in the bid schedule, is included in the
payment for the item of work to which it is made subsidiary. Such items
and the items to which they are made subsidiary are identified in
Section 7 of this specification.

**7. Items of work and construction details**

Items of work to be performed in conformance with this specification and
the construction details therefore are:

[Bid Item 22, Metal Fabrication and Installation]{.underline}

(1) This item shall consist of furnishing and installing the two angle
    iron trash racks with anti-vortex baffles on top of the 60 in. and
    the 72 in. diameter manhole drop inlets and the angle iron trash
    racks for the 48 in. diameter drop inlets as shown on the drawings.
    This shall include bolts required to attach the trash racks to the
    inlets.

(2) The angle iron trash racks shall be fabricated from structural steel
    shapes, flat bar and plates and shall be galvanized after
    fabrication. Shop drawings for each different type and size trash
    rack shall be submitted to the contracting officer for approval
    prior to fabricating the trash racks. The shop drawings shall
    include how the angles and baffle will be cut and welded along with
    the dimensions.

(3) All bolts, nuts and washers for the installation of the trash racks
    onto the 48 in. diameter manholes shall be stainless steel and
    conform to ASTM F593 and F594 alloy Group 1 or Type 304.

(4) Measurement and payment shall be by Method