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Building Design and Construction Handbook - Merritt - Ventech!

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COLD-FORMED STEEL CONSTRUCTION 8.33<br />

TABLE 8.6 Nominal Shear Strength per Spot for Low-Carbon Sheet Steel<br />

Thickness of<br />

thinnest outside<br />

sheet, in<br />

Nominal shear<br />

strength per<br />

spot, kips<br />

Thickness of<br />

thinnest outside<br />

sheet, in<br />

Nominal shear<br />

strength per<br />

spot, kips<br />

0.010 0.13 0.080 3.33<br />

0.020 0.48 0.090 4.00<br />

0.030 1.00 0.100 4.99<br />

0.040 1.42 0.110 6.07<br />

0.050 1.65 0.125 7.29<br />

0.060 2.28 0.190 10.16<br />

0.070 2.83 0.250 15.00<br />

Maintenance of sufficient overlaps in detailing spot-welded joints is important<br />

to ensure consistent weld strengths <strong>and</strong> minimum distortions at joints. Minimum<br />

weld spacings specified in Table 8.5 should be observed, or shunting to previously<br />

made adjacent welds may reduce the electric current to a level below that needed<br />

for welds being made. Also, the joint design should provide sufficient clearance<br />

between electrodes <strong>and</strong> work to prevent short-circuiting of current needed to make<br />

satisfactory spot welds. For further information on spot welding of coated steels,<br />

see ‘‘Recommended Practices for Resistance Welding of Coated Low-Carbon<br />

Steel,’’ American Welding Society, 550 N.W. Lejeune Rd., Miami, FL 33126.<br />

The nominal shear strength per spot, is a function of the thickness of the thinnest<br />

outside sheet. Table 8.6 lists spot shear strengths for sheets with thicknesses from<br />

0.010 to 0.250 in, as recommended for design by the American Iron <strong>and</strong> Steel<br />

Institute.<br />

8.18 BOLTING OF COLD-FORMED<br />

STEEL MEMBERS<br />

Bolting is convenient in cold-formed construction. Bolts, nuts, <strong>and</strong> washers should<br />

generally conform to the requirements of the ASTM specifications listed in Table<br />

8.7. The maximum sizes of bolt holes are given in Table 8.8. St<strong>and</strong>ard holes should<br />

be used in bolted connections when possible. If slotted holes are used, the length<br />

of the holes should be normal to the direction of the shear load. Washers should<br />

be installed atop oversized or slotted holes.<br />

8.18.1 Spacing of Bolts<br />

The distance e, in, measured in the direction of applied force, from the center of a<br />

st<strong>and</strong>ard hole to the nearest edge of an adjacent hole or to the end of the connected<br />

part toward which the force is directed should not be less than e .<br />

min<br />

e � e� (8.41)<br />

min e<br />

e � P/F t (8.42)<br />

u

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