l13 weld connection
TRANSCRIPT
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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 .)