CIVIL ENGINEERING FORMULAS

In bracing and other 12 11

secondary members

Plates supported on two edges or 32 27

webs of box shapesg

Solid cover plates supported on 40 34

two edges or solid websh

Perforated cover plates supported 48 41

on two edges for box shapes

abwidth of element or projection; tthickness. The point of support is the inner line of fasteners or fillet welds con-

necting a plate to the main segment or the root of the flange of rolled shapes. In LRFD, for webs of compact sections, bd, the

beam depth; and for noncompact sections, bD, the unsupported distance between flange components.

bAs required in AASHTO “Standard Specification for Highway Bridges.” The specifications also provide special limita-

tions on plate-girder elements.

cFyspecified minimum yield stress, ksi (MPa), of the steel.

dElements with width /thickness ratios that exceed the noncompact limits should be designed as slender elements.

eWhen the maximum bending moment Mis less than the bending strength Mu,b/tin the table may be multiplied by

.

ffacomputed axial compression stress, ksi (MPa).

gFor box shapes consisting of main plates, rolled sections, or component segments with cover plates.

hFor webs connecting main members or segments for H or box shapes.

Mu/M

190

wfa 55

158

wfa 50

126

wfa 45

51

wfa 16

265