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aisc design guide 16 - errata - flush and extend multiple-row moment end-plate connections

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2.5.2 Design Procedure 2;Thin End-Plate and Larger Diameter Bolts: The following procedure results in a design with a rela-tively thin end-plate and larger diameter bolts.. Calculate the

Trang 1

Revision and Errata List, March 1, 2003

AISC Design Guide 16: Flush and Extended Multiple-Row Moment End-Plate Connections

The following editorial corrections have been made in the First Printing, 2002 To facilitate the incorporation of these corrections, this booklet has been constructed using copies

of the revised pages, with corrections noted The user may find it convenient in some cases to hand-write a correction;

in others, a cut-and-paste approach may be more efficient

Trang 2

2.5.2 Design Procedure 2;

Thin End-Plate and Larger Diameter Bolts:

The following procedure results in a design with a

rela-tively thin end-plate and larger diameter bolts The design

is governed by either the yielding of the end-plate or bolt

rupture when prying action is included, requiring "thin"

plate behavior The "summary tables" refer to Tables 3-2

through 3-5 for the flush end-plate connections and

Ta-bles 4-2 through 4-6 for the extended end-plate

connec-tions The design steps are:

1.) Determine the required plate thickness,

(2-9)

Note: This equation is derived from equating to

given in the "summary tables" as follows:

(2-10)

2.) Select a trial bolt diameter, and calculate the

maximum prying force

For flush end-plate connections and for the interior

bolts of extended end-plate connections, calculate

as follows:

Note that for flush connections Also, the last

term in the numerator of Equation 2-14 represents the

contribution of bolt shank bending in Figure

2-1)

For extended connections, also calculate based

on the outer bolts as follows:

If the radical in either expression for (Equations 2-11 and 2-15) is negative, combined flexural and shear yielding of the end-plate is the controlling limit state and the end-plate is not adequate for the speci-fied moment

3.) Calculate the connection design strength for the limit state of bolt rupture with prying action as follows:

For a flush connection:

(2-15)

(2-16)

(2-17)

(2-18) For an extended connection:

(2-19) where,

distance from the Centerline of each tension bolt row to the center of the compression flange (Note: For rows that do not exist in a connection, that distance d is taken as zero), specified pretension in Table J3.7 of AISC ASD or Table J3.1 of AISC LRFD (also re-produced in Table 2-1 of this Guide)

(2-11)

(2-12)

(2-13)

(2-14)

Rev.

3/1/03

Rev.

3/1/03

min

Rev 3/1/03

=3.682

2

3.682

Trang 3

Comparison of Results for the Two Design Procedures

Design Procedure 1

End-Plate: A572 Gr 50 material

t p = 9/16 in

Bolts: A325

d b = 5/8 in

Design Procedure 2

End-Plate: A572 Gr 50 material

t p = 1/2 in

Bolts: A325

d b = 3/4 in

As expected, Design Procedure 1 results in a thicker

end-plate and smaller diameter bolts than Design

Procedure 2 Either design is acceptable Note: A

check of the design strength of the two designs using

the procedure outlined in Appendix B yields the

fol-lowing:

Design Procedure 1: IM n = 1987 k-in (Thick plate

behavior controlled by bolt rupture – no prying

ac-tion)

Design Procedure 2: IM n = 2108 k-in (Thin plate

behavior controlled by end-plate yielding)

4.2.2 Four-Bolt Extended Stiffened Moment

End-Plate Connection (Table 4-3)

In this four-bolt stiffened example, the required factored

moment of 1,750 k-in and connection geometry of the

four-bolt extended unstiffened connection of Example

4.2.1 is used so that the required end-plate thickness and

bolt diameter can be compared As before, the end-plate

material is A572 Gr 50, the bolts are snug-tightened

A325, and the connection is used in rigid frame

construc-tion as assumed in the frame analysis Both LRFD design

procedures are illustrated

Geometric Design Data

b p = b f = 8 in

t f = 3/8 in

g = 3 in

p f,i = 1 3/4 in

p f,o = 2 1/2 in

p ext = 5 in

h = 24 in

Calculate:

Jr = 1.0 for extended connections

d 0 = 24+2.5-(0.375/2) = 26.3125 in

h 0 = 26.5 in

d 1 = 24-0.375-1.75-(0.375/2) = 21.6875 in

h 1 = 21.875 in

d e = 5-2.5 = 2.5 in

Design Procedure 1 (Thick End-Plate and Smaller Diameter Bolts):

1.) Solve for the required bolt diameter assuming no pry-ing action,

in 59 0

688 21 313 26 90 75 0

1750 2 2

,



SI t n

u reqd

M d

Use d b = 5/8 in

2.) Solve for the required end-plate thickness, t p,reqd,

3.0 2.45in

0 8 2

1 2

?Case 1 governs

p f,i = 1.75 in d s ?use p f,i = 1.75 in

o f

0 i

1 p

p s h s p h g

p s

h s p h

b Y

, ,

, ,

2

1 1 1 1 2









»

»

¼

º

«

«

¬

ª

¸

¸

¹

·

¨

¨

©

§





¸

¸

¹

·

¨

¨

©

§



»

¼

º

«

¬

ª

¸

¹

·

¨

©

§





¸

¹

·

¨

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§



5 2

1 45 2

1 5 26 45 2

1 75 1

1 875 21 2

0 8

in 1 320

5 2 45 2 5 26 45 2 75 1 875 21 0 3

2









0.625 90 /4 27.6k 4

d ʌ

P t b t

p ext

p

1

d d 0

p t

1 w

t g

h

s

f, o

f, i

p tf

h h0

p b

Rev.

3/1/03

Trang 4

k 9 10 ) 5 2 / 75 1 ( 6 15 ) /

c

F

2 2

2

3

¹

·

¨

¨

©

§ c

c

 c

p

o py o

p

F F

a

t

w

Q

k 39

8

5625 0 19 3

9 10 3 50 47

1 4

5625 0 19

¸¸

·

¨¨

§



3.) Calculate the connection design strength for the limit

state of bolt rupture with prying action,

0.75 90/4 39.8k 4

2

ʌ F

d

ʌ

P t b t

>

@

) d )(d (T ) d )(d Q (P

) d d )(d (T )d Q (P

)d (T

) d )(d Q (P )d Q (P M

3 2 1 0 b

2 0 b 3 1 max,i t

3 2 1 b 0 max,o t

2 b

3 1 max,i t 0 max,o t

q

































2

2 2

2 2

2

2 2

maxI

I

I

I

I

39.8 27.9k 7

0 7

0

Use T b = 28 k

>

>

@ 5539kin )

688 28

188 31 688 33 313 38 )(

28 ( 2 75

0

in k 5878 )]

188 31 313 38 )(

28 ( 2

) 688 28 688 33 )(

18 8 8 39 ( 2 [

75

0

in k 5735

)]

688 28 188 31 688 33 )(

28 ( 2

313 38 ) 39 8 8 39 ( 2 [

75

0

in k 6074 ] 188 31 ) 28 ( 2

688 28 688 33 18 8 8 39 2

313 38 39 8 8 39 2 75

0

-M q

































I

4.) Check that IM q > M u If necessary, adjust the bolt

di-ameter until IM q is greater than M u

4600

6074 !

q

M

I k-in so the trial bolt,

3/4 in dia is ok

Note: A check (not shown) of 5/8 in bolt confirms

that 3/4 in is required

Comparison of Results for the Two Design Procedures

Design Procedure 1

End-Plate: A572 Gr 50 material

t p = 5/8 in

Bolts: A325

d b =5/8 in

Design Procedure 2

End-Plate: A572 Gr 50 material

t p = 9/16 in

Bolts: A325

d b = 3/4 in

As expected, Design Procedure 1 results in a thicker end-plate and smaller diameter bolts than Design Procedure 2 Either design is acceptable Note: A check of the design strength of the two designs using the procedure outlined in Appendix B yields the fol-lowing:

Design Procedure 1: IM n = 5460 k-in (Thick plate behavior controlled by bolt rupture – no prying ac-tion)

Design Procedure 2: IM n = 5415 k-in (Thin plate behavior controlled by end-plate yielding)

4.2.5 Multiple Row Extended Stiffened 1/3 Moment End-Plate Connection (Table 4-6)

The required end-plate thickness and bolt diameter for an end-plate connection with the geometry shown below and

a required factored moment of 4,600 k-in is to be deter-mined The end-plate material is A572 Gr 50 and the bolts are fully tightenedA325, and the connection is used in rigid frame construction as assumed in the frame analysis Both LRFD design procedures are illustrated

Geometric Design Data

b p = b f = 8 in

t f = 3/8 in

g = 3 in

Summary: t p = 9/16 in

d b = 3/4 in

p

t

g

tw

pb

d

p t p

b

f, i

p

f, o e

bp

f

s

s

3

h

h1

h0 h

0

d

1

d

3

d

d2

p

t

ext

p

Rev 3/1/03

... 5415 k-in (Thin plate behavior controlled by end-plate yielding)

4.2.5 Multiple Row Extended Stiffened 1/3 Moment End-Plate Connection (Table 4-6 )

The required end-plate. .. thickness and bolt diameter for an end-plate connection with the geometry shown below and

a required factored moment of 4,600 k-in is to be deter-mined The end-plate material is A572 Gr 50 and. .. Procedure results in a thicker end-plate and smaller diameter bolts than Design Procedure Either design is acceptable Note: A check of the design strength of the two designs using the procedure

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