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Table of Contents

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How does ideCAD design brace-center connection according to AISC 360-16?

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Tip
  • Brace-center connection design limit states and geometry checks are done automatically according to AISC 360-16.

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Symbols

Ab: Non-threaded bolt web characteristic cross-sectional area
Ag: Gross area
An: Net cross-section area
Ae: Effective net cross-sectional area
Avg: Gross area under shear stress
Anv: Net area under shear stress
Ant: Net area under tensile stress
d: Characteristic diameter of the stem of the bolt (the diameter of the non-threaded stem of the bolt)
dh: Bolt hole diameter
Fy: Structural steel characteristic yield strength
Fu: Structural steel characteristic tensile strength
s: Distance between bolt-holecenters
Lc: The clear distance between bolt holes
Le: The distance from the center of the bolt hole to the edge of the assembled element
Leh: The horizontal distance from the center of the bolt hole to the edge of the assembled element
Lev: The vertical distance from the center of the bolt hole to the edge of the assembled element
t: Plate thickness
w = Size of weld leg, in. (mm)
Rn: Characteristic strength
Ubs: A coefficient considering the spread of tensile stresses

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Connection Geometry

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Brace-to-Gusset Plate Connection

GEOMETRY CHECKS

Bolt Spacing

The distance between the centers of bolts is checked per AISC 360-16.

smin ≥ 3d       

AISC 360-16 J3.3

 

 

s

60 mm

 

 

d

20 mm

s =60 mm > smin = 3*20=60 mm

Horizontal Edge Distance

The distance from the center of the hole to the edge of the connected part in the horizontal direction is checked per AISC 360-16.

Leh ≥ L e-min     

AISC 360-16 J3.4

 

 

Leh

69.85 mm

 

Le-min

26 mm

Minimum distance check according to Table J3.4

Vertical Edge Distance

The distance from the center of the hole to the edge of the connected part in the vertical direction is checked per AISC 360-16.

Lev ≥ Le-min     

AISC 360-16 J3.4

 

 

Lev

45 mm

Conformity check for Leh ≥ 2d = 2 * 20 = 40 mm application

Le- min

26 mm

Minimum distance check according to Table J3.4

Weld Size

The minimum size of fillet welds is checked according to AISC 360-16 Table J2.4

w ≥ wmin     

AISC 360-16 J2.4

 

 

w

5.658 mm

 

wmin

5 mm

Table J2.4

STRENGTH CHECKS

Bolt Shear at Brace

The bolt shear limit state of the connection is checked according to AISC 360-16.

Ab

Image Removed

Mathinline
body--uriencoded--$$ \normalsize A_b = \dfrac%7B \pi d%5e2%7D %7B4%7D = \dfrac%7B \pi 20%5e2%7D %7B4%7D = 314.159\; \mathrm%7Bmm%5e2%7D $$

Fn

Image Removed

Rn

Image Removed

Mathinline
body--uriencoded--$$ \normalsize F_n = 0.450 F_%7Bub%7D = 0.450 \times 1000 =450 \; \mathrm%7BN/mm%5e2%7D $$

Rn

Mathinline
body--uriencoded--$$ \normalsize R_n = F_n A_b = 2 \times 450 \times 314.159 \times 10%5e%7B-3%7D =282.743 \; \mathrm%7BkN%7D $$

AISC 360-16 J3-1

ΦRn

Image Removed

Mathinline
body--uriencoded--$$ \normalsize \varphi R_n = 0.75 \times 282.743 = 212.058 \; \mathrm%7BkN%7D $$

Required

Ready

Rate

Control

205.872 kN

212.058 kN

0.971

Bolt Bearing on Plate

The bearing strength limit states of the connection plate, which are “shear tear out” and “ovalization of bolt hole” for both end and inner bolts, are checked according to AISC 360-16.

dh

20+2=22 mm

 

Lc,edge

Image Removed

Mathinline
body--uriencoded--$$ \normalsize L_%7Bc,edge%7D = L_e - 0.5d_h = 45 - 0.5 \times 22 =34 \; \mathrm%7Bmm%7D $$

 

Rn

Image Removed

Mathinline
body--uriencoded--\begin%7Baligned%7D \normalsize R_n = \mathrm%7Bmin%7D \left[\begin%7Bmatrix%7D 1.2L_c \times t \times F_u \\2.4d \times t \times F_u \end%7Bmatrix%7D\right] \end%7Baligned%7D

AISC 360-16 J3-6a

Rn-edge

Image Removed

Mathinline
body--uriencoded--\begin%7Baligned%7D \normalsize R_n = \mathrm%7Bmin%7D \left[\begin%7Bmatrix%7D 1.2(34)(15)(470 \times 10%5e%7B-3%7D) \\2.4(20)(15)(470 \times 10%5e%7B-3%7D) \end%7Bmatrix%7D\right] \end%7Baligned%7D =287.64\; \mathrm%7BkN%7D

 

Lc,spacing

Image Removed

Mathinline
body--uriencoded--$$ \normalsize L_%7Bc,spacing%7D = s - d_h = 60 - 22 =38\; \mathrm%7Bmm%7D $$

 

Rn-spacing

Image Removed

 

Rn

Image Removed

Mathinline
body--uriencoded--\begin%7Baligned%7D \normalsize R_n = \mathrm%7Bmin%7D \left[\begin%7Bmatrix%7D 1.2(38)(15)(470 \times 10%5e%7B-3%7D) \\2.4(20)(15)(470 \times 10%5e%7B-3%7D) \end%7Bmatrix%7D\right] \end%7Baligned%7D =321.48\; \mathrm%7BkN%7D

 

Rn

Mathinline
body--uriencoded--$$ \normalsize R_%7Bn%7D = n_eR_%7Bn,edge%7D + n_sR_%7Bn,spacing%7D $$

Mathinline
body--uriencoded--$$ \normalsize R_%7Bn%7D = 1 \times 287.64 + 1 \times 321.48 = 609.12 \; \mathrm%7BkN%7D \; $$

 

ΦRn

Image Removed

Mathinline
body--uriencoded--$$ \normalsize \varphi R_n = 0.75 \times 609.12 = 456.84 \; \mathrm%7BkN%7D $$

Required

Ready

Rate

Control

205.872 kN

456.84 kN

0.451

Bolt Bearing on Gusset

The bearing strength limit states of the connection plate, which are “shear tear out” and “ovalization of bolt hole” for both end and inner bolts, are checked according to AISC 360-16.

dh

20+2=22 mm

 

Lc,edge

Image Removed

Mathinline
body--uriencoded--$$ \normalsize L_%7Bc,edge%7D = L_e - 0.5d_h = 45 - 0.5 \times 22 = 34 \; \mathrm%7Bmm%7D $$

 

Rn

Image Removed

Mathinline
body--uriencoded--\begin%7Baligned%7D \normalsize R_n = \mathrm%7Bmin%7D \left[\begin%7Bmatrix%7D 1.2L_c \times t \times F_u \\2.4d \times t \times F_u \end%7Bmatrix%7D\right] \end%7Baligned%7D

AISC 360-16 J3-6a

Rn-edge

Image Removed

Mathinline
body--uriencoded--\begin%7Baligned%7D \normalsize R_n = \mathrm%7Bmin%7D \left[\begin%7Bmatrix%7D 1.2(34)(10)(470 \times 10%5e%7B-3%7D) \\2.4(20)(10)(470 \times 10%5e%7B-3%7D) \end%7Bmatrix%7D\right] \end%7Baligned%7D =191.76\; \mathrm%7BkN%7D

 

Lc,spacing

Image Removed

Mathinline
body--uriencoded--$$ \normalsize L_%7Bc,spacing%7D = s - d_h = 60 - 22 =38 $$

 

Rn-spacing

Image Removed

Mathinline
body--uriencoded--\begin%7Baligned%7D \normalsize R_n = \mathrm%7Bmin%7D \left[\begin%7Bmatrix%7D 1.2(38)(10)(470 \times 10%5e%7B-3%7D) \\2.4(20)(10)(470 \times 10%5e%7B-3%7D) \end%7Bmatrix%7D\right] \end%7Baligned%7D =214.32\; \mathrm%7BkN%7D

 

Rn

Image Removed

Mathinline
body--uriencoded--$$ \normalsize R_%7Bn%7D = n_eR_%7Bn,edge%7D + n_sR_%7Bn,spacing%7D $$

Mathinline
body--uriencoded--$$ \normalsize R_%7Bn%7D = 1 \times 191.76 + 1 \times 214.32 = 406.08 \; \mathrm%7BkN%7D $$

 

ΦRn

Image Removed

Mathinline
body--uriencoded--$$ \normalsize \varphi R_n = 0.75 \times 406.08 = 304.56 \; \mathrm%7BkN%7D $$

Required

Ready

Rate

Control

205.872 kN

304.56 kN

0.676

Weld Strength

The nominal and design strength of the weld is checked according to AISC 360-16

Fe

490000 kN/m2

w

5.658 mm

Fu-plate

469.999  N/mm2

Fu-brace

410 N/mm2

tplate

15 mm

AISC 360-16 J3-6a

tbrace

15 mm

lw

150 mm

Rnw

Image Removed

Mathinline
body--uriencoded--$$ \normalsize R_%7Bnw%7D = 0.6 \times F_%7Be%7D \times 2 \times 0.707 \times w $$
Mathinline
body--uriencoded--$$ \normalsize R_%7Bnw%7D =0.6 \times 490 \times 2 \times 2 \times 0.707 \times 5.658 = 4704 \; \mathrm%7BkN/m%7D $$

Rn-plate

Image Removed

RnBM

Image Removed

Rn

Image Removed

ΦRn

Image Removed

Mathinline
body--uriencoded--$$ \normalsize R_%7Bn,plate%7D = 0.6 F_%7Bu%7D t l = 0.6 \times 2 \times469.999 \times 15 =8460 \; \mathrm%7BkN/m%7D $$

RnBM

Mathinline
body--uriencoded--$$ \normalsize R_n = \mathrm%7Bmin%7D ( R_%7Bn,plate%7D , R_%7Bn,brace%7D ) =8460 \; \mathrm%7BkN/m%7D $$

Rn

Mathinline
body--uriencoded--$$ \normalsize R_n = \mathrm%7Bmin%7D ( R_%7Bnw%7D , R_%7BnBM%7D )l =4704 \times 150 \times 10%5e%7B-3%7D =705.6\; \mathrm%7BkN%7D $$

ΦRn

Mathinline
body--uriencoded--$$ \normalsize \varphi R_n = 0.75 \times 705.6 = 529.2 \; \mathrm%7BkN%7D $$
 

Required

Ready

Rate

Control

205.872 kN

529.2 kN

0.389

Whitmore Section Compression Yield

The buckling limit state in withmore section of the plate subjected to compression is checked according to AISC 360-16.

K

0.65

 

L

0 mm

 

r

2.887 mm

 

KL / r

0

 

Fy

355 N/mm2

 

Ag

1292.82 mm2

 

Rn

Image Removed

Mathinline
body--uriencoded--$$ \normalsize R_n = F_y A_g = 355 \times 1292.82 \times 10%5e%7B-3%7D =458.95 \; \mathrm%7BkN%7D $$

AISC 360-16 J4-6

ΦRn

Image Removed

Mathinline
body--uriencoded--$$ \normalsize \varphi R_n = 0.90 \times 458.95 = 413.056 \; \mathrm%7BkN%7D $$

 

Required

Ready

Rate

Control

205.872 kN

413.056 kN

0.498

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