bolt connect design

7/23/2019 Bolt Connect Design

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CONNECTION DESIGN


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Hyatt Regency Kansas Walk way collapse !


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Connection Design Requirement

Strength

Stiffness Ductility


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Plate elements of connection

Not Desired Desired


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Connections are largely divided into

two categories

Shear Connections

Moment Connections


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SHEAR FORCE

TRANSFER

(Shear Connection)


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MOMENT

TRANSFER

(MomentConnection)


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BASIC FORCES

Forces in

moment

connection


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CENTERS OF ROTATION IN

MOMENT CONNECTIONS


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Effect of end plate thickness


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Transfer of tension forces


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FAILURE MODES IN TENSION


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Transfer of compression forces


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Special Issues in Connection Design


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Understanding

PRYING

and bolt-plate

interaction


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Splices and base plates


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Column

Splices


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SEMI-RIGID CONNECTION S


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SEMI-RIGID CONNECTIONS IN STEEL FRAMES

Connection costs


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Connection behaviour is relative andhence it needs constant assessment


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Fixed Semi-rigid

Increased sway deflections in semi-rigid frames


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A

B C

D

E F

Typical Steel frame

Steel frame and their connections

Possible onnections

Single web angle

Double web angle

Header Plate

Top angle Seat angle

End Plate

T-stub

Welded Connection


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Rigid

Semi-Rigid

Pinned

Ideally Pinned Connection

Ideally Rigid

Connection

Relative rotation -r

Joint moment - M

Classification of structural steel connections according to their stiffness


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Connection flexibility of beam-column joint

900r

Column Centre

line

Beam Centre

line

B

R2

R1

M

(a) Deformed shape of joint B (b) Centre line diagram

(Exaggerated scale)

LC

B

C

AA

C


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A

B C

D

E F

(a) Actual

frame

Steel frame connections and their

modelling

JA

JB JC

JD

JE JF

(b) Idealised

frame


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O

Joint characteristics (M-rrelationship)

Strength of joint

Mc

Relative rotation r

Moment

M

A

Ductility of

joint

Initial stiffness, J=r

M


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Strength of joint Mc

Relative rotation r

Moment M

Three parameter model for M-rrelationship

J=

0=

n=1

n=2n=4

n=

Rigid : J=

Hinged : J=0

O

Connection Stiffness and their representation

{ } n/1n)o/r(1rJM

+

=

r

M

J

CM


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A B

C

UDL - 30 kN/m

45 kN 45kN

8m 6.67m

2m 2m

Continuous beam with flexible connection

E=2.08kN/m2

I=8.325e-5 m4

J=40000 kN-m

J

2I I

Gauss

sidel

Final

moments(app.)

+134.219 -123.820 +123.820 0.000

FEM FinalMoments

+134.724 123.970 123.970 0.000

Studies on linear semi-rigid analysis and design of steel frames


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Thank You

bolt connect design

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