PROJECT: STEEL BUILDING DESIGN CASE STUDYSUBJECT: Bracing connection, gusset plate design. SHEET 122 of 131Brace line B1, second floor.

Fy = specified (ASTM) minimum yield stressFu = specified (ASTM) minimum tensile strengthRn = strength t = thickness of connected partPu = factored load to be resistedd = diameter of the bolteb = one-half the depth of the beam, in.ec = one-half the depth of the column, in.

db = depth of the beam, in.dc = depth of the column, in.w.p. = working point.N = horizontal distance of gusset plate, in.V = vertical distance of gusset plate, in.

Aw =cross section area of the whitmore sectionPu = 127.0 k

B C D 96 k

Elevation View 13

A E30

Plan View

Member A-E, Interior floor girder:W24x68 ASTM 992

db = 23.7 inFy = 50 ksiFu = 65 ksi

Member A-B, Interior column:W10x49 ASTM 992

dc = 9.98 inFy = 50 ksiFu = 65 ksi

Member A-C, Brace:2L6x4x1/2LLBB A36

Fy = 36 ksiFu = 58 ksi

f = resistance factor

a = distance from the face of the column flange to the centroid of the gusset-to-beam connection, in.b = distance from the face of the beam flange to the centroid of the gusset-to-column connection, in.

Gusset Plate

W.P.

ColumnW10x49

GirderW24x68

15

2L6x4x1/2Brace

13

Red font indicates user inputPROJECT: STEEL BUILDING DESIGN CASE STUDYSUBJECT: Bracing connection, gusset plate design. SHEET 123 of 131

Use A325-N bolts in standard holes,3/4 in diameter.

Design shear strength of one bolt, double shear (LRFD Table 7-10) 31.8 k

Check bearing strength @ each bolt hole:

45.7 kips > 31.8 kips OK!

Check tension yielding on the Whitmore section:

3.5 iny

6

248.0 kips > 127.0 kips OK!

Aw = (y + y + 2.5(Perp. distance between center of holes))*0.5

fRn =

fRn = f (2.4 * d * t * Fu) =(f = 0.75)

y = tan 30o * 6 =

30° *Note: Assume simplified Whitmore section (double dashed area) for the purpose of this lab. This design will be more conservative.

fRn = f (Fu * Aw) =(f = 0.9)

ColumnBrace

13

15Gusset Plate Whitmore section

Girder

Red font indicates user inputPROJECT: STEEL BUILDING DESIGN CASE STUDYSUBJECT: Bracing connection, gusset plate design. SHEET 124 of 131

Distribution of brace force to beam and column:(Uniform force method)

From the member and frame geometry

eb = db/2 = 11.85 in qec = dc/2 = 4.99 in 13

1.15415

in order to remain free of moments on the connection interfaces, the following expression must be satisfied:

allow 1/2 in. between gusset and columnfor the setback

8.68 in

Try a gusset plate :

1/2 in. x 20 1/8 in. horizontally x 13 3/4 in. vertically

a = 16.5 inb = 6.7 in

16.4138 in

0.09 in OK! (If Less Than One)

Use a = 16.5 in and b = 6.7 in

tanq =

tan q * eb - ec = a - b * tan q

a - b * tan q =

a' = tan q * eb - ec + b * tan q =

a - a' =

a

b

15

13

N

BraceColumn

0.5

Gusset Plate

V

Girdereceb

W.P.

N = 20 1/8 inV = 13 3/4 in

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