L13 Weld Connection

8/12/2019 L13 Weld Connection

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LectureLecture 1133 Welded Connections IWelded Connections I

Advantages of Welding

Types of Welding

Welding Symbols

Groove & Fillet Welds

Allowable Strength of Welds

Slot and Back Welds

Timber and Steel DesignTimber and Steel Design

Mongkol JIRAVACHARADET

S U R A N A R E E INSTITUTE OF ENGINEERING

UNIVERSITY OF TECHNOLOGY SCHOOL OF CIVIL ENGINEERING

Advantages of WeldingAdvantages of Welding

Disadvantages of WeldingDisadvantages of Welding

- Fatique

- Inspection Cost

- Economic : save gusset and spice plates

- Applicability : such as connection of steel pipe column

- Rigidity & Continuity : strong joint makes one-pieces construction

- Easier to make changes during construction

- Relative silence


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Welding Process

Electric arc produces 3600 oCbetween section to be weldedand the electrode.

Filler and Base metal are melt in a weld pool and join into onehomogeneous solid

Arc is shielded by slag to protect molten metal from air

Welding InspectionWelding Inspection

1. Visual inspection

2. Liquid penetrants

3. Magnetic particles

4. Ultrasonic testing

5. Radiographic procedures


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Classification of WeldsClassification of Welds

Types of welds made:Types of welds made:

Fillet welds Groove welds

Fillet welds

Plug weldsSlot welds

Typical uses of fillet weldsTypical uses of fillet welds

Lapped plate Stitch plate Slotted connection

Beam bearing plateTee connection Bracket


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Typical uses of fillet weldsTypical uses of fillet welds

Column base plate Pipe connection Beam bracket

Built-up sections

Positions of welds:Positions of welds:

Overheadwelds

Flat weld

Verticalweld

Horizontalweld

Classification of WeldsClassification of Welds


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Types of joint:Types of joint:

Lap Butt

Tee Edge Corner

Examples of Lap JointsExamples of Lap Joints

Ease of fitting : pieces dont required precise fabrication.pieces can be slightly shifted for adjustment

Ease of joining : edge of pieces dont needspecial preparation and are usually shearedor flame cut.


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L-P

T

S(E)

R

AF

Reference line & Arrow

Arrow side & Other side

arrowside

other side

below=arrow and above=other

Weld-all-around

The open circle at thearrow/reference line junction


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&&

Fillet Welds - For lap joints, corner joints and T joints

- Triangular in cross-section

Transverse fillet weld Longitudinal fillet weld


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Example of Fillet Welds

Symbol As built

8 8 mm

8 mm

Symbol As built

6 x 106 mm

10 mm

Example of Fillet Welds

Symbol As built

88 mm8 mm

1515 cm

Symbol As built

6 5-10

5 cm 10 cm

6 mm

6 mm


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Groove Welds- Commonly used to make edge-to-edge joints

8 mm max.

(a)

Reinforcement

(b) (c)

Reasons for having reinforcement:

(a) To take care of pits and other irregularities

(b) Too difficult to make weld surface equal to material

(a) (b)

(c) (d)

Spacer

Land

Types of Groove Weld3

3 mm

"groove" is created by either a tight fitor a slight separation of the edges. Theamount of separation, if any, is given onthe weld symbol.

Square groove weld

60 o

60 o

60 o

60 o

3

3 mm

V-groove weld , in which the edges of both pieces are chamfered, eithersingly or doubly


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60 o

60 o

60 o

60 o

106

60 o

6 mm

10 mm

10

10 mm

If the depth of the V is not the full thickness--or half the thickness in thecase of a double V--the depth is given to the left of the weld symbol.

40o

40 o

The bevel groove weld , in which theedge of one of the pieces is chamferedand the other is left square.

The U-groove weld , in which the edgesof both pieces are given a concavetreatment.

60 o

60 o

15

15 mm

40 o

40o

15

15 mm

The J-groove weld , in which the edge ofone of the pieces is given a concavetreatment and the other is left square.


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The flare-V groove weld , commonly used to join two round or curved parts.The intended depth of the weld itself are given to the left of the symbol, withthe weld depth shown in parentheses.

25 (16)

16 25

The flare bevel groove weld , commonly used to join a round or curvedpiece to a flat piece.

20 (10)

20 mm

20 mm10 mm

10 mm

Plug & Slot Welds - Used to join overlapping members, one of which hasholes in it.

- Weld metal is deposited in the holes and penetratesand fuses with the base metal.

22 8

88

22 mm

(3)

25 8-12(2)

Section thru plug

15 Det. B

Det. B

25

8 cm

12 cm25 mm

Section thru plug

15 mm

8 cm


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P

45 o

Throat = 0.707 legP

(a) (b)

FILLET WELDSFILLET WELDS

Leg

LegRoot

Theoretical throat

Theoretical faceWeld face

(a) Convex

Weld face

Theoretical throat

(b) Concave

45 o

size

size

Throat = size cos 45 o

= size 0.707

sizeL

P

P

Failureplane

Shear stress: f v =0.707 size L

P


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size

size

T h r

o a t

45 o

Throat = size cos 45 o = 0.707 size

: F v = 0.30 F u

E60: F u = 60 ksi = 4,200 kg/cm 2 E70: F u = 70 ksi = 4,900 kg/cm 2 E80: F u = 80 ksi = 5,600 kg/cm 2

: P = 0.707 size L F v : P = 0.707 size F v

E60XX: 2,500 ksc E70XX: 2,500 4,200 ksc

E80XX: 4,500 ksc

13.3 ( . ./ .)

1660142516

12501070121040890108307108620530652044553102673

E70E60 ( . .)

E70XX size 5 mm: 0.707 (0.5) (0.3) (4,900) = 520 kg/cm


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Material thickness Min. size

t 6 mm 3 mm

6 mm < t 12 mm 5 mm

12 mm < t 19 mm 6 mm

t 19 mm 8 mm

1) Min . length of fillet weld 4 leg size

x 4 x

2) Max. weld size :- t 6 mm, weld size = t

- t > 6 mm, weld size = t - 2 mmWeldsize

t = Materialthickness

3) Min. weld size :

5) Longitudinal fillet: weld length weld distance

weld distance 20 cm

(( ))

4) End return length 2 weld size

P P EndReturn

6) Min . lap joint 5 thickness 25 mm

Weld length

Welddistance P

P t

P


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P P 20 cm

15 cm

10 mm

PL 2 x 20

13-1 A36, E70 10 .

10 . . = 1,040 ./ .

= (15+20+15)(1,040)/1,000 = 52

= (2 x 20)(0.60 x 2.5) = 60

P = 52

P P

PL 1 x 10

13-2 A36 E70 1 x 10 .

= 15(1,000)/830 = 18 . 2 x 0.8 = 1.6 .( 2 .)

= 18/2-2 = 7.0 .( 10 .)

P = (1.0)(10)(0.6)(2.5) = 15 = 10 2 = 8 ., = 5 .

8 . = 830 ./ .


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Slot and Back Weldswhen welds length not sufficient

:1. 8 . 2

2. 16 .,

16 ., 16 .

3.

41

stress)lowable(width)(alload

= L

15 cm

P P

Slot weld

Weld on backof channel

L

= t w 2 = 10.5 2 = 8.5 .( 8 . .)

8 . = 830 ./ . = 80(1,000)/830 = 96 . > 68

13-3 C380x54.5 80 E70

15 .

15 cm

80 t 80 t

Slot weld

Weld on backof channel

C380x54.5(t w =10.5 mm)


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8 .=(830)(15+15+38-2.5)/1,000=

= 80 54.4 = 25.6

= 25.6/(2.5 x 0.30 x 4.9) = 7.2 .( 7.5 .) = 10(1.05) = 10.5 . > 7.5 .OK

2.5 x 7.5 .

= 10.5 + 8 = 18.5 .

= 2 1/4 x

= (2.25)(t w ) = 2.25(10.5)

= 24 .( 25 .)

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L13 Weld Connection