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Riveted Joints

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The fastenings (i.e. joints) may be classified into the following two groups :1. Permanent fastenings, and2. Temporary or detachable fastenings.

Introduction

The permanent fastenings are those fastenings which can not be disassembled without destroying the connecting components. The examples of permanent fastenings in order of strength are soldered, brazed, welded and riveted joints.The temporary or detachable fastenings are those fastenings which can be disassembled without destroying the connecting components. The examples of temporary fastenings are screwed, keys, cotters, pins and splined joints.

Rivet parts

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The function of rivets in a joint is to make a connection that has strength and tightness. The strength is necessary to prevent failure of the joint. The tightness is necessary in order to contribute to strength and to prevent leakage as in a boiler or in a ship hull.

Method of Riveting

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5

Lap joints

Butt joints cover platemain plate

Types of Riveted Joints

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Repeating group

Boiler joints (pressure joints)Repeating group

Inner cover plate

outer cover plateStructural joints

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Multiple rows

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long pitch

back pitch

diagonal pitch

short pitch

intermediate pitch

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Efficiency:

compares the strength of the joint with that of solids plates

P0P0

Efficiency = P1/P0

P1P1

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(1) Shearing (at connector)

(2) Tearing (of plate)

t

11

(3) Bearing (of plate)

(4) Unlikely to occur

if the distance from the edge of the plate to the connector is large enough (1.75-2 times the diameter of the connector)

b

12

3.25

in calculation: 11/16 in.rivet holeD D

2

2

2( )4

2 (11/16) 88004

6533.5 lb.

d

(1) Rivet capacity (shearing of rivet and bearing failure)

s sP AShearing:

D

13

3.25

(1) Rivet capacity (shearing of rivet and bearing failure) (cont’) b = 19 ksi

2( )

7 112( ) 19000

16 1611429.7 lb.

ttd

(2) Tearing capacity (tension failure of plate) t = 11 ksi

tP

bearing:b b bP A

11 7(3.25 ) 11000

16 1612332 lb.

tearing:

t t tP A

Hence the strength of the repeating section is 6533.5 lb per 3.25 in.

3.25”

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2

4

DF p

6533.50.418 41.8 %

3.25 (7 /16) 11000

6533.5 lb. per 3.25sP

2 6533.56 lb

4 3.25

Dp D

2(15 12) 6533.56(15 12)

4 3.25p

134 psi.p

Internal pressure

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(1) Preliminary calculation: load that can transmitted by one rivet (shear or bearing)

(2) Possible method of failure

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17

30060 MPa

5650

130 MPa5

40080 MPa

5

b

t

d = 20.5 mm

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P-19.8 kN

19.8 kN

Row 1 (has 1-rivet)

19.8 kN

single shear

main plate

cover plate

19

P-37.3 kN

37.3 kN

P-26.7 kN

26.7 kN

Row 1 (has 1-rivet)

Hence strength of row-1 is 19.8 kN

main plate

cover plate

main plate

cover plate

crash in the main plate

37.3 kN

37.3 kN

P

crash in the cover plate

26.7 kN

26.7 kN

P

20

Row 2 (has 2-rivets)

19.8 kN

59.4 kN

double shear

2 x 19.8 kN

19.8 kN

39.6 kN

P-99 kN

Shear strength at row-2 is

2 39.6 79.2 kN 2 x 19.8 kN

2 x 19.8 kN

2 x 19.8 kN

21

crushing at cover plate

53.4 kN

4 26.7 106.8 kN

19.8 kN

P-126.6 kN4 x 26.7 kN

73.2 kN

2 x 26.7 kN

One possible bearing strength at row-2 is

2 x 26.7 kN

Row 2 (has 2-rivets)crushing at main plate

37.3 kN One possible bearing strength at row-2 is2 37.3 74.6 kN

19.8 kN

P-94.4 kN2 x 37.3 kN

37.3 kN

57.1 kN

37.3 kN

Hence strength of row 2 is 74.6 kN

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Row 3 (has 2-rivets)

Hence strength of row 3 is also 74.6 kN2 x 37.3

kN

37.3 kN

37.3 kN

crushing at main plate

4 x 26.7 kN

2 x 26.7 kN

2 x 26.7 kN

crushing at cover plate

2 x 19.8 kN

2 x 19.8 kN

double shear

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Total rivet capacity

19.8 kN74.6 kN 74.6 kN

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Tearing at row 1 of main plate Tearing at row

2 of main plate

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19.8 kN 74.6 kN 74.6 kN

Row 1 Row 2Row 3 80 MPa

14 mm

180 mm

20.5 mm

t

t

p

d

main plate1P

180 mmp t

main plate

19.8 kN

2P80 MPat

main plate

19.8 kN

37.3 kN

37.3 kN

3P80 MPat

1 ( ) tP p d t (180 20.5) 14 80 178.6 kN

2 ( 2 ) 19.8 kNtP p d t

175.5 kN

3 ( 2 ) 19.8 74.6 kNtP p d t 250.1 kN

Tearing capacity of main plate

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Tearing capacity of cover plate

P

P

Row 1 Row 3Row 2

19.8 kN

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79.2 111.2

190.4 kNcP

P

Row 1 Row 3Row 2

19.8 kN

outer cover plate

19.8 kN

19.8 kN

19.8 kN

9.9 kN

9.9 kN

79.2 kN

80 10 (180 2 20.5)

111.2 kN

80 MPat

inner cover plate

180 mmp

10 mmt20.5 mmd

( 2 )tP t p d

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Rivets failure: 169.0 kN

Tearing of main plate: 175.5 kN

Tearing of cover plate: 190.4 kN

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Assume each rivet carries a load proportional to its resisting shear area

1/2

1/2

1

1

2

2

2

Totally 9 shear areas:

the average load transmitted by 1 shear area is 36 / 9 4 kipssP

12-5 STRESSES IN BEARING-TYPE CONNECTIONS

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the average shearing stress is

Row1 Row2 Row3

4 kips

3/ 8 in

1/ 2 in 4 kips

4 kips

3/ 8 in

3/ 8 in

1/ 2 in

the maximum average bearing stress is

8=17.07 ksi

1 15( )

2 16

bb

P

td

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4=5.80 ksi

15/ 4 ( )4 16

sP

d

15 in

16d

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15 116 2

3610.2 ksi

(8 )t

15 116 22

36 4

(8 )

10.45 ksi

t

main plate (Row 2)

36 kips 2 kips

2 kips

main plate (Row 1)

36 kips

main plate (Row 3)

36 kips8 kips

8 kips

2 kips

2 kips

15 116 22

36 20

(8 )

5.23 ksi

t

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Upper cover plate

16 kips4 kips

4 kips

2 kips

2 kips

4 kips

Lower cover plate

20 kips4 kips

4 kips

2 kips

2 kips

2 kips

2 kips

4 kips

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Lower cover plate

20 kips4 kips

4 kips

2 kips

2 kips

2 kips

2 kips

4 kips

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Lab joints (ต่�อทาบ) Butt joints (ต่�อชน)

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shearing capacity of 1-rivet2( / 4)sP d

295( 19 / 4) N

26.935 kN

bearing capacity of 1-rivet

( )b bP td

220(8 19) N

33.44 kNupper plate1P

250 mmL t

9 26.935 kN

242.42 kNrivetP

Total rivets capacity

1.5 mmhole rivetd d 20.5 mm

1 ( )t holeP t L d

140 8 (250 20.5) N 257 kN

Row1

37

1.5 mmhole rivetd d

2 26.94 kN ( 2 )t holeP t L d

140 8(250 2 20.5) N

2 261 kNP

upper plate2P

250 mmL 26.94 kN

tRow2

3 3 26.94 kN ( 3 )t holeP t L d

140 8(250 3 20.5) N

Row3

t

3P26.94 kN

26.94 kN

26.94 kN3 291.9 kNP

Hence the joint capacity is 242.42 kN

Efficiency =242.42 kN

86.6%140 8 250 N

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44

45

(1.5,4)

(1.5,0)

(1.5,-4)

(4.5,4)

(-4.5,0)

(-4.5,4)

(-4.5,-4)

(4.5,0)

(4.5,-4)

(-1.5,0)

(-1.5,4)

(-1.5,-4)

28.82.4 kips

12dxP

38.43.2 kips

12dyP

38.4 4.5 kips.inT

172.8 kips.in

Twisting moment

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ให้�น�สิ�ต่พยายามท�าโจทย�ข้�อ 1220 ถึ�งข้�อ 1240 ให้�ได้�นะครั�บ

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สิ�าห้รั�บรัอยต่�อแบบ friction type ให้�ค�ด้แบบเด้"ยวกั�บรัอยต่�อแบบ bearing type ยกัเว�นไม�ต่�องค�านวณค�าห้น�วยแรังแบกัทาน (Bearing

stress) ท"&เกั�ด้ข้�'นรัะห้ว�าง bolt และ plate

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strength of butt weld

allowable stress lenght of weld thickness of the thinner plate

Butt Weld

allowable stress allowable stress of base metal

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tO45

Othroat sin 45 0.707t t

Fillet Weld

base on AISC, for E70 electrodes, A36 steel 21 ksiallow

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E70 : 21 ksi

14.9 kips/in.q t

3 1 5

8 16 16t

3/8

Ans

4.66 kips/in.

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Ans

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Centroid:

Torsional couple:

Polar moment of inertia:

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62

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