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7/30/2019 Topic -Tension Members
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Structural Steel Design
Tension Members
Dr. Seshu Adluri
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Stell Tension -Dr. Seshu Adluri
Tension in
Nature Tension members are the most
efficient and economical of allstructural elements
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Stell Tension -Dr. Seshu Adluri
Tension Members Used From
Primitive Times
If you wantyour grandkids to playTarzanand theTensionMember,
save theforests!
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Stell Tension -Dr. Seshu Adluri
(Wo)Man-made Tension Structures
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Stell Tension -Dr. Seshu Adluri
Typical
tensionmembers
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Steel and Tension
Steel in TensionExcellent in Tension (and compression)
Very ductile (highly desirable structuralproperty for stress redistribution and safety)
Connections induce loss of effective area Bolt holes, etc.
Shear lag in outstanding parts (of both bolted andwelded connections)
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Typical
cross-sections
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Material behaviour
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Material behaviour
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Stresses in tension members
(gross-section)
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Stresses innet-section
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Basic Failure modes
Yielding of gross c/s Limiting the capacity to yield prevents very large
deformations (before strain hardening kicks in)
Rupture (fracture) of net c/s Localized yielding and strain hardening is permitted
Ultimate stress is the limit for the local c/s in the
connection zone
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Plate in Tensionwith Bolts
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Plate in Tension with Bolts
b b
aa
8 x in. bar
Gusset plate
7/8 in. diameter hole
Section a-a
Section b-bb b
aa
8 x in. bar
Gusset plate
7/8 in. diameter hole
b b
aa
8 x in. bar
Gusset plate
7/8 in. diameter hole
Section a-a
Section b-b
Section a-a
Section b-b
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Angle in Tension with Bolts
L 4 x 4 x 3/8
db = 5/8 in.
Gusset plate
a
a
Section a-a
L 4 x 4 x 3/8
db = 5/8 in.
Gusset plate
a
a
L 4 x 4 x 3/8
db = 5/8 in.
Gusset plate
L 4 x 4 x 3/8
db = 5/8 in.
Gusset plate
a
a
Section a-aSection a-a
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Rupture
of net
section
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Typical Truss Connection
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Typical Frame Connection
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Shear lag
Out-standing parts of rolled sectionsLegs of angles, flanges, etc.
Connected parts due to insufficient load
transfer in the connection zone
Single side welds
Two side welds of insufficient lengths
Cl.12 (effective net areas)
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Shear lag
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Shear lag
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Shear lag effect
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Length of connection (for shear lag)
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Eccentricity of elements
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Stell Tension -Dr. Seshu Adluri
Staggered bolts
Tear out paths can be inclineds2/4g rule (Cl. 12)
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Stell Tension -Dr. Seshu Adluri
Gauge Length
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Stell Tension -Dr. Seshu Adluri
T
T
Shear failure
Tension failure
(a)
(b)
(c)
T
T
Shear failure
Tension failure
Shear failure
Tension failure
(a)
(b)
(c)
Block Shear Tear-out
Cl. 13.11
Paths parallel
to load
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Block Shear Tear-out Cl. 13.11
Paths parallel & perpendicular to load