beam column base plate design[1]

8/11/2019 Beam Column Base Plate Design[1]

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Beam-Column Base Plate DesignLRFD Method

ENGINEERING J OURNAL /FIRS T QUARTER / 1999

Richard M. Drake is Principal Structural Engineer, Fluor

Daniel, Irvine, CA.

Sharon J. Elkin is Structural Engineer, Fluor Daniel, Irvine,

CA.

29

1

2

3

4

4

INTRODUCTION

RICHARD M. DRAKE and SHARON J. ELKIN

IB

N

b

d

f

m

N . dm

nM

P V

B . bn

x

tdx f

t

Fig. 1. Base Plate Design Variables

o o o o

o oo o o

oo o o

o o oo o o o

oo o o o

o oo

o o o oo o o

o o oo o o

oo o o o o

o o oo o o o o

o o

o

o

o

o o oo o o o

o o o

o o o

o

o o

o o

o

o o o o o o o

o o o

o o o

o o

o o

o o

o

o o

o o o o

o o

o o o o

o o o o

o o o

o o o o

o o

o o o o

where:

t is c mm n design practice t design a building r struc-base plate width perpendicular t m ment direc-

ture beam-c lumn with a m ment-resisting r fixed base.ti n, in.

Theref re the base plate and anch r r ds must be capablebase plate length parallel t m ment directi n, in.

f transferring shear l ads, axial l ads, and bending m -c lumn flange width, in.

ments t the supp rting f undati n.verall c lumn depth, in.

Typically, these beam-c lumn base plates have beenanch r r d distance fr m c lumn and base plate

designed and/ r analyzed by using service l ads r bycenterline parallel t m ment directi n, in.

appr ximating the stress relati nship assuming the c m-base plate bearing interface cantilever directi n

pressi n bearing l cati n. The auth rs present an ther parallel t m ment directi n, in.appr ach, using fact red l ads directlyin a meth d c nsis-

tent with the equati ns f static equilibrium and the LRFD 0 95(1)Specificati n.

2The m ment-resisting base plate must have design

base plate bearing interface cantilever perpendic-strengths in excess f the required strengths, flexural ( ),ular t m ment directi n, in.axial ( ), and shear ( ) f r all l ad c mbinati ns.

A typical beam-c lumn base plate ge metry is sh wn0 80in Figure 1, which is c nsistent with that sh wn n page

(2)211-61 f the LRFD Manual.

base plate tensi n interface cantilever parallel t

m ment directi n, in.

(3)2 2

c lumn flange thickness, in.

The pr gressi n f beam-c lumn l adings, in rder f in-

creasing m ments, is presented in f ur l ad cases.

Case A is a l ad case with axial c mpressi n and shear,

with ut bending m ment. This case results in a full length

unif rm pressure distributi n between the base plate and

the supp rting c ncrete. This case is summarized in the

LRFD Manual beginning n page 11-54 and is summa-

rized herein f r c mpleteness.

Case B ev lves fr m Case A by the additi n f a smallbending m ment. The m ment changes the full length

unif rm pressure distributi n t a partial length unif rm

pressure distributi n, but is n t large en ugh t cause sepa-

rati n between the base plate and the supp rting c ncrete.

Case C ev lves fr m Case B by the additi n f a spe-

cific bending m ment such that the unif rm pressure dis-

tributi n is the smallest p ssible length with ut separati n

f

u

u u

f

f

f


2/10


5

5

CASE A: NO MOMENTNO UPLIFT

CASE B: SMALL MOMENT WITHOUT UPLIFT

M P

e

MM

ePP

P NM

Ne

Y N e

N Ye

Y

Fig. 2. No Moment - No Uplift

Fig. 3. Small Moment Without Uplift

o o o

o o o o o o

o o o o o

o o o o o

o o o o

o o o o o o

o o o

oo o o oo o o

oo

o oo o

o o o o oo o o

o o oo o o o o

o o

o o o o o o o

o o o o o o o

o o o o o o o o

o o o o o o

o o o o o

o o

o o o o o

o o o o o o

o o o o

o o o

o o

o o

o o o

o o o

o

between the base plate and the supp rting c ncrete. This 1. Assume that the resultant c mpressive bearing stress

c rresp nds t the c mm n elastic limit where any addi- is directly under the c lumn flange.

ti nal m ment w uld initiate separati n between the base 2. Assume a linear strain distributi n such that the an-

plate and the supp rting c ncrete. ch r r d strain is dependent n the bearing area

Case D ev lves fr m Case C by the additi n f suffi- strain.

cient bending m ment t require anch r r ds t prevent 3. Assume independent strain distributi n.

separati n between the base plate and the supp rting c n-

All three meth ds summarized by AISC assume a lin-crete. This is a c mm n situati n f r fixed base platesear triangular distributi n f the resultant c mpressive

in structural ffice practice. That is, a rigid frame with abearing stress. This implies that the beam-c lumn base

fixed base plate will usually attract en ugh bending m -plate has n additi nal capacity after the extreme fiber

ment t require anch r r ds t prevent uplift f the basereaches the c ncrete bearing limit state. The auth rs pr -

plate fr m the supp rting c ncrete.p se that a unif rm distributi n f the resultant c mpres-

sive bearing stress is m re appr priate when utilizing

LRFD.If there is n bending m ment r axial tensi n at the base Case B, a beam-c lumn with a small m ment and n

f a beam-c lumn, the anch r r ds resist shear l ads but uplift at the base plate elevati n, is sh wn in Figure 3.are n t required t prevent uplift r separati n f the base The m ment is expressed as l cated at s me ec-plate fr m the f undati n. Case A, a beam-c lumn with centricity ( ) fr m the beam-c lumn neutral axis.n m ment r uplift at the base plate elevati n, is sh wn

in Figure 2.

0

(4)0

06If the magnitude f the bending m ment is small relative

t the magnitude f the axial l ad, the c lumn anch r0r ds are n t required t restrain uplift r separati n f 6

the base plate fr m the f undati n. In service, they nly2resist shear. They are als necessary f r the stability f

the structure during c nstructi n.(5)AISC addresses three different variati ns f the elastic

2meth d when using an ultimate strength appr ach f r the

where:design f beam-c lumn base plates subjected t bending

bearing length, in.m ment.

u u

u

uu

u

uu


3/10

ENGINEERING J OURNAL /FIRS T QUARTER / 1999 31

3

1

CASE C: MAXIMUM MOMENT WITHOUT

UPLIFT

CONCRETE BEARING LIMIT STATE

LRFD Specification Requirements

CASE D: MOMENT WITH UPLIFT

N

Me

P

P N M

M Ne e

P

P NM

PNe

NY N e N

Y N

P P

N

P . f A

Fig. 5. Moment With Uplift

Fig. 4. Maximum Moment Without Uplift

o o o

o o

o o oo o

o oo o o

o o o oo o

o

o o o

o o o

o o o

o o

o o o

o o

o o

o o o o

o o o

o

o o

o

o oo o o

o o o

shear. Case D, a beam-c lumn with sufficient m ment t

cause uplift at the base plate elevati n, is sh wn in Figure

5. This is the m st c mm n case in design practice, espe-The maximum m ment with ut base plate uplift is as-cially f r rigid frames designed t resist lateral earthquakesumed t ccur when the c ncrete bearing limit state is

r wind l adings n the building r structure.reached ver a bearing area c ncentric with the applied

l ad at its maximum eccentricity. If the eccentricity ex-

ceeds , the tendency f r uplift f the plate is assumed t6ccur. This assumes a linear pressure distributi n in acc r-

dance with elastic the ry and n tensi n capacity between

the base plate and supp rting c ncrete surfaces. Case C, a

beam-c lumn with the maximum m ment with ut uplift

at the base plate elevati n, is sh wn in Figure 4.

(4)

06

(4) (7)6

06

T satisfy static equilibrium at the c ncrete bearing limit

state, the centr id f the c ncrete bearing reacti n ( )

must be aligned with the line- f-acti n f the applied axial6l ad.

2 26

2 The LRFD Specificati n defines the c ncrete bearing(6)3 limit state in Secti n J9.

(8)

When the m ment at the beam-c lumn base plate exceeds On the full area f a c ncrete supp rt:

, anch r r ds are designed t resist uplift as well as0 85 (LRFD J9-1)6

u

u

u u

u

u

uu

p

u c p

p c


4/10


12

11

2 2

1 1

12

2 1

12

12

1

22

1

22

1

2

1

2

2

1

12

2 1

1

Case B: Small Moment Without Uplift

Practical Design ProcedureRequired Area

Case C: Maximum Moment Without Uplift

Case D: Moment with Uplift

Case A: No Moment - No Uplift

A BYAP . f A

A Y N e

A AP . . f BY . . f BY

A A

P qY

P q N ef

A

A q A

A y

y e

e P

e

N

P MP P

M P eN

eq

A BYA

q . f B . f BA Y N

Aq . . f B . . f B A

A P . . f BY . . f BY BY

Aq . f B . f B AA P . f B N . f B N

B N

P . qN A

NA M P e P

M . qN

A

A

P M f B f

A BNA

P . f BY qY A A

P . . f BN . . f BN A M

ePP qN

o o o

o o o

o o

o o o o o o oo o o o

o

o o o o o o o

o o o o o

o o o

o o

o o o

o o o o o

o

o

o o

o o o

o o o o o

o o o o

o o o

o o o o

o o o o o

o o o

o o o o o

o o

On less than the full area f a c ncrete supp rt:

0 85 (LRFD J9-2)( 2 )

2 (0 60)(0 85) (0 60)(0 85) (2)

where:

c mpressi n resistance fact r = 0.60 ( 2 ) (12)specified c ncrete c mpressive strength, ksi

N te that equati n 12 is n t a cl sed f rm s luti n be-area f steel c ncentrically bearing n a c ncretecause;supp rt, in.

maximum area f the p rti n f the supp rting is a functi n f ,surface that is ge metrically similar t and c n- is a functi n f ,centric with the l aded area, in. is a functi n f , and

is a functi n f .

H wever, if is defined as s me fixed distance r asSelect base plate dimensi ns such that: s me percentage f , the c rresp nding maximum values

f and can be determined directly.(8)

And n ting that:

(9) As previ usly stated, Case C is the situati n where uplift

is imminent and .F r c nvenience, define a new variable, , the c ncrete6

bearing strength per unit width (K/in).

0 85 0 85 (2) 2(6)

3

(0 60)(0 85) (0 60)(0 85) (2)(0 60)(0 85) (0 60)(0 85) (2)

0 51 1 02 (10) 2 20 51 1 02

23 3F r m st c lumn base plates bearing directly n a c n- 3crete f undati n, the c ncrete dimensi n is much greater

than the base plate dimensi n, and it is reas nable t 0 667 (13)

assume that the rati 2. F r m st c lumn( )

6base plates bearing n gr ut r a c ncrete pier, the c n-

crete (gr ut) dimensi n is equal t the base plate dimen-0 111 (14)si n, and it is reas nable t c nservatively take the rati

1.

Given the f ll wing:, , , , , inches & kips

0 85 (15)(0 60)(0 85) (0 60)(0 85) (2)

(4)(11)

p c

u c c

u

c u

c

u

u uu c p

u u

c cc c

c cu c c

c cu c c

u

u u u

u

u u c c

c p c c

u c cu

uu


5/10

ENGINEERING J OURNAL /FIRS T QUARTER / 1999 33

3

vertical

2

2

2

2

2

2

2 2 2

2

2

ANCHOR ROD SHEAR AND TENSION LIMIT

STATES


Required Strength

Practical Design ProcedureRod Sizes

T Y

F

T P P V F A

T qY P T F A

T F . f

N YP f P e f

F . fN Y

qY f P e f

VqY N qY .qY f P e f

F

Aq N TY q f Y P e f

F

f

VY f

A

aY bY c

Fb b ac

Y

a

Fq f q f P f e

Y

f

N N P f e VY f f fq A

T

Y

T qY P

Y

N Y VqY f P e f V . F A

o o o o o o

o o o o

o o o

o oo o o o

o o

o oo o o o

o o o

o o o

o o

o o o

o

o o o o

o o

o

o o

o o o

o

o o

o o o

o

o o

o o o

o o oo o o

o o o o

o

o o

o

Tw equati ns will be needed t s lve f r the tw un-

kn wns, the required tensile strength f the anch r r ds,

, and bearing length, .

T maintain static equilibrium, the summati n f verti-

cal f rce must equal zer : The LRFD Specificati n defines the anch r r d (b lts)

shear and tensi n limit states in Secti ns J3.6 and J3.7,0

and Tables J3.2 and J3.5.0 (21)

(16) (22)

F r ASTM A307 b lts:T maintainstatic equilibrium, the summati n f m ments

taken ab ut the f rce must equal zer : 59 1 9 45 (Table J3.5)

F r ASTM A325 b lts, threads excluded fr m the shear( ) 0 plane:2 2

117 1 5 90 (Table J3.5)

( ) 0 (17) where:2 2

required anch r r d shear strength, kipsanch r r d resistance fact r 0 75( ) 0

n minal shear strength, ksi2 2anch r r d n minal (gr ss) area, in.

required anch r r d tensile strength, kips( ) 0 (18)2 2 n minal tensile strength, ksi

anch r r d shear stress, ksiThis is in the f rm f a classic quadratic equati n, with

unkn wn . (23)

0 (19) F r A307 b lts:

24 ksi (Table J3.2)4

F r A325 b lts when threads are excluded fr m the shear2 plane:

60 ksi (Table J3.2)4 [ ( )]

2The shear stress ( ) is calculated c nsidering the required

shear strength f the c lumn base.

2 ( )(20) (24)2 2

where:T determine the ther unkn wn, , substitute the value

number f r ds sharing shear l ad, unitlessf r int the equati n:

N te that all the base plate anch r r ds are c nsidered(16)effective in sharing the shear l ad.

As a check, back substitute the value f r int the

equati n:

( ) 0 (17) 0 75 (25)2 2

u

u u c p vub b

u u tub b

u t v

c p u

t v

u

ub

uv

b

ubu

t

v

ubv

b

v

vqN N

u

q

v

uub

vv b

u

v

u u

uu vub b

v


6/10

ENGINEERING J OURNAL /FIRS TQU ARTER /199934

2

2

8 9

3 6

2

27

3

2

BASE PLATE FLEXURAL YIELDING LIMIT

STATE


Required StrengthTension Interface

Required StrengthBearing InterfaceNominal Strength

VF .

A mM f

TT . F A

nM f

f

dbn

nM f

c m n n

cM f

n

Fc

n

M M

M M

Mx

MT xM

M B

m n f tM M F

P M

o o o

o o o

o o o o

o o o o o o

o o o oo

o o o o o

o o o o o

o o o

o o o o o o o o o o

o o o

o o

o o o

o o o

o o o o o

o o o o

o o o

o o oo o

o o

o o o o

o o oo o

o o

o o o o

o o oo

o oo

o o o o o o o

o o o o

o

o o o o

o

oo o

o

o

o

o oo

o o

o

On secti n parallel t c lumn flanges:

59 1 9 45 (26)

(29)2

0 75 (27)On secti n parallel t c lumn web:

where:

(30)number f r ds sharing tensi n l ad, unitless 2

N te that all f the base plate anch r r ds are n t c n- where:sidered effective in sharing the tensi n l ad. F r m st base

c ncrete bearing stress, ksiplate designs, nly half f the anch r r ds are required t

resist tensi n f r a given l ad c mbinati n. The bearing pressure may cause bending in the base plateThe embedment, edge distances, and verlapping shear in thearea between theflanges, especiallyf r lightly l aded

c nes f the anch r r ds int the c ncrete mustbe checked c lumns. Yield line the ry is used t analyze this c n-t assure that the design tensile strength als exceeds the siderati n.required tensile strength. This check sh uld be in acc r-

dance with the appr priate c ncrete design specificati n, (31)4and is bey nd the sc pe f this paper.

Itsh uldbe n tedthatbase plateh les are ften versized ( )(32)withrespectt the anch r r ds. Inthiscase, s meslippage

2may be necessary bef re the anch r r d shear limit state

is reached. F r large shear l ads, the designer may ch se Let the larger f , , and :t investigate alternate shear transfer limit states inv lving

pretensi ned b lts, fricti n and/ r shear lugs.(33)

2

where:

yield line the ry cantilever distance fr m c lumnThe entire base plate cr ss-secti n can reach the specifiedweb r c lumn flange, in.yield stress ( ).largest base plate cantilever, in.

N te that f r m st base plate ge metries, the cantileverdimensi n ( ) is very small and c rner bending f the

TheLRFDSpecificati n definesthe flexural yieldinglimitbase plate is neglected. When the dimensi n is large t

state in Secti n F1.acc mm date m re anch r r ds r m re bearing surface,

c rner bending plate m ments sh uld be c nsidered and(28)

used in the base plate thickness calculati ns.

(LRFD F1-1)

where:The tensi n n the anch r r ds will cause bending in the

required base plate flexural strength, in-Kbase plate f r the cantilever distance .

flexural resistance fact r = 0.90F r a unit width f base plate:

n minal flexural strength, in-K

plastic bending m ment, in-K(34)

The bearing pressure between the c ncrete and the baseF r a unit width f base plate:

plate will cause bending in the base plate f r the cantilever

distances and . The bearing stress, (ksi), is calculated(35)c nsidering the required axial and flexural strength f the

4c lumn base, and respectively.

ubt

b

ppl

utub b

t

pplt

p

,

f

,

ppl

ppl

y

nbpl

n p

pl

b

n

uppl

p pn p y

u u


7/10

ENGINEERING J OURNAL /FIRST QUARTER /1999 35

( )

22

( )

( )

2

( )

2

( )

( )

( )

23

( )

Practical Design ProcedureBearing Interface Case D: Moment with Uplift

Base Plate Thickness

Practical Design ProcedureTension Interface Base

Plate Thickness

DESIGN EXAMPLE 1

Case A: No MomentNo Uplift

Case B: Small Moment Without Uplift

Case C: Maximum Moment Without Uplift

Pf

BYt

M MT x

t .

M M BF

t Y mcf . F

Pt . c

BY Ff

t . cF Y m

P mt .

BF

M M

tT x. F

B

T xt .

BF

Pf

BN

Pt . c

BN F

P Pf

BY B N e

Pt . c

B N e F

P P . Pf

BY BNB Nm .

. Pt . c x .

BN F

Fig. 6. Design Example 1

Required:

Solution:

o o

o oo

o o

o o

o o

o

(44)Setting the design strength equal t the n minal strength

and s lving f r the required plate thickness ( ):F r all cases:

(28)

2 11 (45)

(LRFD F1-1)

If :0 90

2 4

1 49 (46)

1 49 (36)If :

2 11 (47)

Setting the design strength equal t the n minal strength

and s lving f r the required plate thickness:

(28)

0 904

2 11 (37)

(38)

1 49 (39)

(40)( 2 )

1 49 (41) a) Design anch r r ds( 2 )b) Determine base plate thickness

1. Dimensi ns:1 5(42)

22.0 in. 0.95(12.12 in.)5 24 in. (1)

2

1 5 16.0 in. 12.12 in. 0.605 in.1 49 (43) 2 24 in. (3)

2 2 2

up

p

nbplu

p req

n p y

pp y

up req

yp

p reqy

Yu

p reqy

pbpl

puy

up req

y

up

up req

y

u up

up req

y

u u up

up req

y


8/10


2

34

2

2

2

5

( )

2.27 in.2

( )

Select: Base Plate 2 20 1-10

o.k.

DESIGN EXAMPLE 2

o.k.

o.k.

Select: 4 - 3/4 in. Diameter Anchor Rods

e .

N. . e, Case D

q .

q .

Nf .

f e . .

.Y . .

.

. . .

T .

.V

F A .

V

.

F . .

T

F A .

T

Y . . m, n nP

.Mt .

m .

t .

x .controls

Fig. 7. Design Example 2

Required:

Solution:

o o o o

o o

o o o

o

o o o

o o o

o o

o o o

o

o

o

2. Eccentricity:

6. Check bearing n c ncrete bel w gr ut layer120 ft-K(12 in./ft)11 08 in. (4) The gr ut is 2 in. thick. Assume that the c ncrete130K

extends at least 2 in. bey nd gr ut in each directi n.22.0 in.

3 67 in. 11 08 in. (7)6 6 (24 in.)(6.67 in.)

(0 51)(4 ksi)(20.0 in.) (10)

(20 in.)(2.27 in.)3. C ncrete bearing:76.6 K/in. 61.2 K/in. used in designAssume the bearing n gr ut area will g vern.

(0 51)(6 ksi)(20.0 in.) 1 61.2 K/in. (10)

16.0 in. 22.0 in.19 0 in.

2 2 2

16.0 in.11 08 in. 19 08 in.

2

2(130)(19 08)19 0 (19 0) (20)

61 2

19 0 16 73 2 27 in.61 2 K/in.(2.27 in.) 130 K 8.92 K (16)

4. Anch r r d shear and tensi n:

Check 4 in. dia. anch r r ds

30 0 K7.50 K (25)

4

0 75(24 ksi)(0.4418 in. )

7.96 K 7.50 K

7 50 K

59 1 9 26 7 ksi (26)0.4418 in.

8.92 K4.46 K (27)

2

a) Determine required tensile strength0 75(26.7 ksi)(0.4418 in. )b) Determine base plate thickness

8.85 4.46 K

N te that this pr blem is Example 16 fr m the AISC

C lumn Base Plate Steel Design Guide Series.5. Base plate flexural yielding:1. Required strength: (LRFD A4-2)

2 27 in. 5 24 in. and n t applicable1.2(21K) 1.6(39K) 87.6K

(8 92 K)(2.24 in.)1.2(171 in.-K) 1.6(309 in.-K) 700 in.-K2 11 0.35 in. (45)

(20.0 in.)(36 ksi)2. Dimensi ns:

14.0 in. 0.95(7.995 in.)3 20 in. (1)(130 K) 5.24 in. 2

2 11 (47)(20.0 in.)(36 ksi) 11.0 in. 7.995 in. 0.435 in.

1 72 (3)2 2 21.82 in.

u

ub

v b

ub

t

ub

t b

ub

u

up req

p req


9/10

ENGINEERING J OURNAL /FIRST QUARTER /1999 37

3

2

5

( )

2.45 in.2

( )

14

5

14

14

12

SUMMARY AND CONCLUSIONS

Required Tensile Strength 17.3 KREFERENCES

Select: Base Plate 1 14 1 -2

NOMENCLATURE

e.

N. . e, Case D

q .

Nf .

f e .

. .Y . .

.

. . .

T .

Design Of Welded Structures

Y . . m, n nStructural Steel Design, LRFD Approach

.t . .

. Man-t .

ual Of Steel Construction, Load & Resistance Factor

Designcontrols Col-

umn Base Plates

Engineering Journal,

Design.Of Anchor Bolts In Petrochemical Facilities

.

Engineering Journal

.

Engineering Journal

.

A

o o o o

o o o o o

o o o

o o o

o o o o o

o o o

o o

o o

o o o o

o o

o o o

o o

o o o o o o

o o o

o o

o o

o o o

o o

o

o

o

o o o

o o o o

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3. Eccentricity: f r the design f the anch r r ds is slightly smaller

because the centr id f the c mpressi n reacti n is700 in.-K7.99 in. (4) a greater distance fr m the anch r r ds.87 6 K

14.0 in.2 33 in. 7 99 in. (7)

6 6 A meth d l gy has been presented that summarizes the4. C ncrete bearing: design f beam-c lumn base plates and anch r r ds using

fact red l ads directly in a manner c nsistent with the(0 51)(3 ksi)(14 in.) 4 42.8 K/in. (10) equati ns f static equilibrium and the LRFD Specifi-

cati n. Tw design examples have been presented. A11.0 in. 14.0 in.12 5 in. direct c mparis n was made with a pr blem s lved by2 2 2

an ther AISC meth d.11.0 in.

The step-by-step meth d l gy presented will be benefi-7 99 in. 13.49 in.2 cial in a structural design ffice, all wing the design prac-

titi ner t use the same fact red l ads f r the design f the2(87 6)(13 49)

steel structure, base plate, and anch r r ds. In additi n the12 5 ( 12 5) (20)42 8 unif rm rectangular pressure distributi n will be easier

t design and pr gram thanthe linear triangular pressure12 5 10 05 2 45 in.distributi n utilized in all wable stress design and ther

42 8 K/in.(2.45 in.) 87.6 K 17.3 K (16)

published LRFD f rmulati ns.

5. Base plate flexural yielding: 1. Bl dgett, Omer W., ,

1966.2 45 in. 3 20 in. and n t applicable2. Smith, J. C., ,

2nd Editi n, 1996.(17 3 K)(1.72 in.)2 11 0 51 in. (45) 3. American Institute f Steel C nstructi n (AISC),(14.0 in.)(36 ksi)

L ad and Resistance Fact r Design Specificati n f r

Structural Steel Buildings, December 1, 1993.(87 6 K) 3.20 in. 4. AmericanInstitute f Steel C nstructi n (AISC),

2 11 (47)(14.0 in.)(36 ksi)

, 2nd Editi n, V lume 2, 1994.1.24 in. 5. American Institute f Steel C nstructi n (AISC),

, Steel Design Guide Series, 1990./6. Shipp, J.G., and Haninger, E.R., Design Of Headed

6. C mparis n:Anch r B lts, V l 20, N . 2,

AISC s luti n f r this pr blem: (2nd Qtr.), pp 58-69, AISC, 1983.

7. American S ciety f Civil Engineers (ASCE),Required Anch r R d Tensile Strength 21 2 K,p p 4 - 3 t

Select: Base Plate 1 / 14 1 -2 4-8, 1997.

Length f triangular c mpressi n bl ck 5 1 in. 8. Th rnt n, W. A., Design f Small Base plates f r

Wide-Flange C lumns, , V l 27,Auth rs s luti n f r this pr blem:

N . 3, (3rd Qtr.), pp 108-110, AISC, 1990a.

Required Anch r R d Tensile Strength 17 3 K 9. Th rnt n, W. A., Design f Small Base plates f rWide-Flange C lumns - A C ncatenati n fMeth ds,Select: Base Plate 1 / 14 1 -2

, V l 27, N . 4,(4thQtr.), pp108-Length f rectangular c mpressi n bl ck 110, AISC, 1990b.2 45 in.

Remarks:

area f steelc ncentricallybearing n a c ncreteThe auth rs s luti n yields the identical basesupp rt, in.plate size and thickness. Required tensile strength

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maximum area f the p rti n f the supp rting c lumn v erall depth, in.

surface that is ge metrically similar t and c n- axial eccentricity, in.

centric with the l aded area, in. anch r r d distance fr m c lumn and base plate

anch r r d n minal (gr ss) area, in. centerline parallel t m ment directi n, in.

baseplate width perpendiculart m ment direc- specified c ncrete c mpressive strength, ksi

ti n, in. c ncrete bearing stress, ksi

n minal tensile strength, ksi anch r r d shear stress, ksi

n minal shear strength, ksi base plate bearing interface cantilever parallelspecified minimum yield stress, ksi t m ment directi n, in.

n minal flexural strength, in.-K base plate bearing interface cantilever perpen-

plastic bending m ment, in.-K dicular t m ment directi n, in.

required base plate flexural strength, in.-K yieldlinethe rycantileverdistancefr mc lumn

web r c lumn flange, in.required flexural strength, in.-K

c ncrete ( r gr ut) bearing strength per unitbase plate length parallel t m ment directi n,

width, kips/in.in.

c lumn flange thickness, in.n minal bearing l ad n c ncrete, kips

base plate thickness, in.required axial strength, kips

base plate tensi n interface cantilever parallel trequired tensile strength, kips

m ment directi n, in.required anch r r d tensile strength, kips

anch r r d resistance fact r = 0.75required shear strength, kips

flexural resistance fact r = 0.90required anch r r d shear strength, kips

c mpressi n resistance fact r = 0.60bearing length, in.

number f r ds sharing tensi n l ad, unitlessc lumn flange width, in.

number f r ds sharing shear l ad, unitlesslargest base plate cantilever, in.

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beam column base plate design[1]

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