Common Grade Bolts

3.4.1

Common Grade Bolts

ASTM A 307 bolts shall be tightened to a "snug tight" fit. "Snug tight" is

the tightness that exists when plies in a joint are in firm contact. If

firm contact of joint plies cannot be obtained with a few impacts of an

impact wrench, or the full effort of a man using a spud wrench, contact the

Contracting Officer for further instructions.

3.4.2

High-Strength Bolts

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NOTE: The four bolt tightening methods currently

allowed by AISC will provide acceptable results if

bolt assemblies are kept free of dirt and rust, if

properly lubricated, and if proper installation

procedures are followed. Because these conditions

are rarely encountered during normal construction,

use only direct tension indicator tightening methods

where slip critical connections are required.

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NOTE: Include bracketed item for all jobs and

delete the first sentence of the paragraph. Slip

critical connections must be identified on the

drawings.

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ASTM A 325M ASTM A 325 and ASTM A 490M ASTM A 490 bolts shall be fully

tensioned to 70 percent of their minimum tensile strength. [Provide load

indicator bolts or washers in all [ASTM A 325M ASTM A 325M] [or] [ASTM A

490M ASTM A 490] bolted connections, except provide only load indicator

washers for slip critical connections. Direct tension indicator

tightening, [, or installation of alternate design fasteners,] shall be the

only acceptable tightening methods. Use only direct tension indicator

tightening for slip critical connections.] Bolts shall be installed in

connection holes and initially brought to a snug tight fit. After the

initial tightening procedure, bolts shall then be fully tensioned,

progressing from the most rigid part of a connection to the free edges.

3.4.2.1

Installation of Load Indicator Washers (LIW)

ASTM F 959M ASTM F 959. Where possible, the LIW shall be installed under

the bolt head and the nut shall be tightened. If the LIW is installed

adjacent to the turned element, provide a flat ASTM F 436M ASTM F 436

washer between the LIW and nut when the nut is turned for tightening, and

between the LIW and bolt head when the bolt head is turned for tightening.

In addition to the LIW, provide flat ASTM F 436M ASTM F 436 washers under

both the bolt head and nut when ASTM A 490M ASTM A 490 bolts are used.

3.5

WELDING

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NOTE: For jobs in Iceland, in lieu of AWS welders

and inspectors, use "Technological Institute of

Iceland" certified welders and inspectors.

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