FIGURE P354 Design of Tension Members Select a singleangle t

FIGURE P3.5-4 Design of Tension Members Select a single-angle tension member of A36 steel to resist a dead load of 28 kips and a live load of 84 kips. The length of the member is 18 feet, and it will be connected with a single line of 1-inch-diameter bolts, as shown in Figure P3.6-1. There will be four or more bolts in this line. a. Use LRFD b. Use ASD 3.6-1 Bolt line

Solution

LFRD

Load combination = 1.2D +1.6L = 28*1.2 +84.1.6 =168 Kip

yielding criteria = 36 ksi

Pn = 0.9 *yield strength A_g = 0.9*36*Ag =168

Ag= 5.185 in²

use L 8X8X3/4 with Ag= 8*3/4= 6 in ²

for altimate strength

Pn = 0.75*f_u*Ae

Ae= (8-1-1/16)*3/4 =5.20 in²

Pn = 0.75*58*5.2=226 kip > 168 kip hence safe

ASD

Load combination

D+L = 28+84 =112 kips

yield cretria

Ag = FOS*Pn/(*f_y) = 1.5*112/(36) =4.66 in ²

Use L8x8x5/8 section

with area Ag= 8x5/8 = 5 in²