**[CONSTRUCTION SPECIFICATION]{.underline}**

**[455. METAL BEAM GUARD RAILING]{.underline}**

**1. [SCOPE]{.underline}**

> The work shall consist of furnishing and installing metal beam guard
> railing complete with all posts, post blocks spacers, plate washers,
> backup plates, terminal end and return sections, bolts, nuts, all
> other fittings and appurtenances.

**2. [MATERIALS]{.underline}**

The rail elements, backup plates, terminal, end and return sections,
bolts, nuts, and other fittings shall conform to the specifications of
AASHTO Desig­nation M 180. The rail elements, backup plates, terminal end
and return sections shall conform to Class A, Type 1 W‑Beam guard
railing as shown in AASHTO Designation M 180. The rail metal, in
addition to conforming to the requirements of AASHTO Designation M 180,
shall withstand a cold bend, without cracking, of 180 degrees around a
mandrel of a diameter equal to 2.5 times the thickness of the plate.

All completed steel components and hardware for railings shall be
galvanized in accordance with the provisions in AASHTO Designation M 180
and Section 3, Galvanizing of this specification.

> After galvanizing, all elements of the railing shall be free of fins,
> abrasions, rough or sharp edges, and other surface defects and shall
> not be kinked, twisted or bent. If straightening is necessary, it
> shall be done by methods approved by the Engineer. Kinks, twists, or
> bends in railing elements may be cause for rejection of the railing
> elements.
>
> Abraded or damaged galvanized surfaces of steel railing and posts and
> ends of steel railing cut after galvanizing, shall be cleaned and
> re-galvanized as specified for galvanizing, except if permitted by the
> Engineer, repairs to the surfaces may be made in accordance with the
> provisions in Section 3, Galvanizing of this specification.
>
> Workmanship shall be equivalent to good commercial practice and all
> edges, bolt holes and surfaces shall be free of torn metal, burrs,
> sharp edges and protrusions.
>
> Bolts shall have shoulders of such shape that will prevent the bolts
> from turning. Holes in rail elements shall be of similar shape as the
> bolt shoulder.
>
> Steel posts and blocks shall be fabricated from steel complying with
> the requirements of ASTM Designation A 36/A 36M. Steel tubing used for
> post blocks shall conform to the requirements of ASTM Designation A
> 500, Grade B, or ASTM Designation: A 501.

3.  **GALVANIZING**

Galvanizing of products fabricated from rolled, pressed and forged steel
shapes, plates, bars and strip 3.2 mm thick or thicker, shall conform to
the specifications of ASTM Designation A 123. Galvanizing of material
3.2 mm thick or thicker shall be performed after fabrication into the
largest practical sections.

At the option of the Contractor, material thinner than 3.2 mm shall be
galvanized either before fabrication in conformance with the
requirements of ASTM Designation

A 525M, Coating Designation Z600, or after fabrication in conformance
with the requirements of ASTM Designation A 123, except that the weight
of zinc coating shall average not less than 365 grams per square meter
of actual surface area with no individual specimen having a coating
weight of less than 305 grams per square meter.

Fabrication shall include all operations such as shearing, cutting,
punching, forming, drilling, milling, bending, welding, and riveting.

All welded areas shall be thoroughly cleaned prior to galvanizing to
remove all slag or other material that would interfere with the
adherence of the zinc. When it is necessary to straighten any sections
after galvanizing, the work shall be performed without damage to the
zinc coating.

> Galvanizing of iron and steel hardware and nuts and bolts, when
> specified or shown on the plans, shall conform to the specifications
> of ASTM Designation A 153, except whenever threaded studs, bolts,
> nuts, and washers are specified to conform to ASTM Designation A 307,
> A 325/A 325M, A 449, A 563/A 563M, or F 436 and zinc coating is
> required, they shall be hot-dip zinc coated or mechanically zinc
> coated in accordance with the requirements of the ASTM Designations.
> Unless otherwise specified, galvanizing shall be performed after
> fabrication.
>
> Components of bolted assemblies shall be galvanized separately before
> assembly.
>
> Tapping of nuts or other internally threaded parts to be used with
> zinc coated bolts, anchor bars or studs shall be done after
> galvanizing and shall conform to the requirements for thread
> dimensions and over tapping allowances in ASTM Designation A 563/A
> 563M.
>
> Galvanized surfaces that are abraded or damaged at any time after the
> application of the zinc coating shall be repaired by thoroughly wire
> brushing the damaged areas and removing all loose and cracked coating.
> The cleaned areas shall be painted with two (2) applications of either
> of the following options:
>
> a\. Zinc dust - zinc oxide primer, ASTM D 79, and D 520
>
> b\. Zinc-rich cold galvanized compound, brush, or aerosol application.

**4. [INSTALLING POSTS]{.underline}**

> Steel posts shall be driven. If ground conditions are such that pilot
> holes are necessary to prevent damage to posts during driving, any
> space around steel posts after driving shall be filled with dry sand
> or pea gravel.
>
> Posts shall be placed at equal intervals, as shown on the drawings,
> except that the end posts may be spaced closer to adjacent posts if
> directed by the Engineer.

**5. [INSTALLING METAL RAILING AND FITTINGS]{.underline}**

The edges and center of the rail element shall contact each post block.
Rail element joints shall be lapped not less than 320 mm (12.6 inches)
and bolted.

> Rail elements shall be spliced at intervals not to exceed 3.8 m (12.5
> feet) and the splices shall be made at posts, unless otherwise shown
> on the drawings. The rail elements at joints shall have full bearing.
>
> All metal work shall be fabricated in the shop, and no punching,
> cutting, or welding will be permitted in the field. Rail elements
> shall be lapped so that the exposed ends will not face approaching
> traffic.
>
> Terminal sections shall be installed in accordance with the
> manufacturer's recommendations.
>
> The bolted connection of the rail element to the post shall withstand
> a 22-kN pull at right angles to the line of the railing.

**6. [MEASUREMENT AND PAYMENT]{.underline}**

Metal beam guard railing will be measured to the nearest 0.1 meter along
the face of the rail element from end post to end post of the completed
railing at each installation. The point of measurement at each end post
will be the center of the bolt attaching the rail element to the end
post.

Payment will be made at the contract unit price for the metal beam guard
railing including all posts, post blocks spacers, plate washers, backup
plates, terminal end and return sections, bolts, nuts, all other
fittings and appurtenances. Such payment will constitute full
compensation for all labor, materials, equipment, and all other items
necessary and incidental to the completion of the work.

> Compensation for any item of work described in the contract but not
> listed in the bid schedule will be 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]{.underline}**

> Items of work to be performed in conformance with this specification
> and the construction details are:
>
> **a. [Bid Item 32, Metal Beam Guard Railing]{.underline}**
>
> \(1\) This item shall consist of furnishing all materials and
> installing the Metal Beam Guard Railing complete with all posts, post
> blocks spacers, plate washers, backup plates, terminal end and return
> sections, bolts, nuts, all other fittings and appurtenances as shown
> on the drawings and specified herein.
>
> \(2\) Section 2, [Materials]{.underline}, shall apply. All dimensions
> for the metal beam guard railing, posts and appurtenances shall be as
> shown on the drawings.
>
> \(3\) At the option of the contractor, posts may be installed in
> drilled holes and backfilled with concrete. Concrete for posts shall
> be in accordance with Construction Specification 31, Class 21 (3000).
> Class 28 (4000) maybe used at the Contractor's option.
>
> \(4\) Section 6, [Measurement and Payment]{.underline} shall apply.
> Payment shall include full compensation for furnishing and installing
> the post concrete backfill, Subsidiary Item, [Concrete Class 21
> (3000]{.underline}), if the contractor chooses to install posts in
> drilled holes.