# Axial Load Capacities for Single Plates

Based on Gross Section Loaded Uniformly in Either Tension or Compression

Compression per AISC 9th Edition Manual (ASD)

#### Input Data

Fy = | ksi | Fy = yield stress | ||

Lc = | in. | Lc = unbraced length for compressive buckling | ||

K = | K = effective length factor for compression |

Gross tension capacity of plate: Rt = Ft*Ap

where:Ft = 0.60*Fy and Ap = Hp*tp

Compression (buckling) capacity of plate: Rc = Fa*Ap | |

where: Ap = Hp*tp | |

r = tp/(SQRT(12)) (radius of gyration for minor axis of plate) | |

KL/r = K*Lc/r (slenderness ratio) | |

Cc = SQRT(2*p^2*29000/Fy) | |

If KL/r <= Cc then Fa = (1-(K*Lc/r )^2/(2*Cc^2))*Fy/(5/3+3*(K*Lc/r)/(8*Cc)-(K*Lc/r)^3/(8*Cc^3)) | |

If KL/r > Cc then Fa = 12*p^2*29000/(23*(K*Lc/r)^2) | |

In the case of bracing gusset plates, the concept of the

"Whitmore Section" may be used to

determine the effective height of the gusset plate

to be used in analysis.

The "Whitmore Section" consists of the total

effective width at the end of the brace as determined by

drawing 30 degree lines spreading or fanning outward from the

point where the load is initially delivered to the gusset plate from

the brace and continuing to where these lines

intersect a line parallel to and at the end of the brace.

In the case of a bolted brace, this would be

from the first row of bolts to the end of the brace.

In the case of a welded brace, this would be from

the beginning of the welds to the end of the brace.

"Whitmore Section" may be used to

determine the effective height of the gusset plate

to be used in analysis.

The "Whitmore Section" consists of the total

effective width at the end of the brace as determined by

drawing 30 degree lines spreading or fanning outward from the

point where the load is initially delivered to the gusset plate from

the brace and continuing to where these lines

intersect a line parallel to and at the end of the brace.

In the case of a bolted brace, this would be

from the first row of bolts to the end of the brace.

In the case of a welded brace, this would be from

the beginning of the welds to the end of the brace.

In the case of bracing gusset plates,

the concept of the "Whitmore Section" may be used to

determine the effective height of the gusset

plate to be used in analysis.

The "Whitmore Section" consists of the total

effective width at the end of the brace as determined

by drawing 30 degree lines spreading or fanning outward from

the point where the load is initially delivered to the

gusset plate from the brace and continuing to where these

lines intersect a line parallel to and at the end of the brace.

In the case of a bolted brace, this would be from the first row

of bolts to the end of the brace.

In the case of a welded brace, this would be

from the beginning of the welds to the end of the brace.

the concept of the "Whitmore Section" may be used to

determine the effective height of the gusset

plate to be used in analysis.

The "Whitmore Section" consists of the total

effective width at the end of the brace as determined

by drawing 30 degree lines spreading or fanning outward from

the point where the load is initially delivered to the

gusset plate from the brace and continuing to where these

lines intersect a line parallel to and at the end of the brace.

In the case of a bolted brace, this would be from the first row

of bolts to the end of the brace.

In the case of a welded brace, this would be

from the beginning of the welds to the end of the brace.

**Disclaimer: **This calculator is not intended to be used for the design of actual structures, but only for schematic (preliminary) understanding of structural design principals. For the design of an actual structure, a competent professional should be consulted.

‘Calculations courtesy of Alex Tomanovich, PE ’