Iii design-of-steel-structures-unit-2

AACE Engineering College : Ankushapur, Ghatkesar, Telangana 501301 (EAMCET Code: ACEG)
Unit 2.1 Tension Members
2
TENSION MEMBERS
1. Introduction
• Tension members are linear members in which axial forces act so as
to elongate (stretch) the member. A rope, for example, is a tension
member. Tension members carry loads most efficiently, since the
entire cross section is subjected to uniform stress. Unlike compression
members, they do not fail by buckling.
• Ties of trusses, suspenders of cable stayed and suspension bridges,
suspenders of buildings systems hung from a central core (such
buildings are used in earthquake prone zones as a way of minimising
inertia forces on the structure), and sag rods of roof purlins are other
examples of tension members.
• Tension members are also encountered as bracings used for the lateral
load resistance. In X type bracings the member which is under tension,
due to lateral load acting in one direction, undergoes compressive
force, when the direction of the lateral load is changed and vice
versa. Hence, such members may have to be designed to resist tensile
and compressive forces.
2. Types of Cross-sections
• The tension members can have a variety of cross sections. The single
angle and double angle sections are used in light roof trusses as in
industrial buildings. The tension members in bridge trusses are made of
channels or I sections, acting individually or built-up.
• The circular rods are used in bracings designed to resist loads in tension

2 Design of Steel Structures
For Micro Notes by the
Student
only. They buckle at very low compression and are not considered
effective.
• Steel wire ropes are used as suspenders in the cable suspended
bridges and as main stays in the cable-stayed bridges.
3. Net Effective Sectional Area (An
) or (Anet
)
An
= Ag
– Sectional area of bolt or rivet holes
(a) Plate of flat with chain Bolting
Net effective sectional area of plate or flat with chain bolting along section
a-b-c-d-e

A B n d t
n o
# #
= −
^ h
(b) Plate or flat with staggered (Zig-Zag) Bolting
Net effective sectional area of plate or flat with staggered bolting along

3 Tension Members
Student
a-b-c-d-e
A B n d
g
P
g
P
t
4 4
n o
1
1
2
2
2
2
# #
= − + +
d n
Ag
= Gross sectional area of plate
An
= Net sectional area of plate
B = Width of plate
n = Number of bolts
do
= Diameter of bolt hole
t = Thickness of plate
Example: 5.1.
Example: 5.1
A steel plate is 300 mm wide and 10mm thick. An unfinished bolt of M18 is
driven in to it. The net sectional area of the plate is
(a) 3000mm2
(b)2820mm2
(c)2800mm2
(d)1400mm2
Sol:

Student
Example: 5.2
A plate of 200mm wide and 12mm thick is used as tension member is
connected to connect gusset plate using M18 bolts as shown in figure. The
critical net sectional area of plate is
(a) 1920mm2
(b) 2201mm2
(c) 2242mm2
(d) 2160mm2
Sol:

5 Tension Members
Student
Limit State Design Concepts
4. Types of failures in a tension member
(a) Gross section yielding failure of the member (Limit state of yielding in
the gross section)
(b) Net section rupture failure of the member (Limit state of fracture or
rupture)
(c) Block shear failure of the member.
5. Design strength of tension member (Td
)
(a) Design tensile strength of section based on gross section yielding (Tdg
):
Nominal or characteristic tensile strength of member by considering
gross section yielding
T A f
ng g y
#
=
Design tensile strength of member by considering gross section yielding

T
T A f
dg
mo
ng
mo
g y
#
γ γ
= =
Exame: 5.3.
Example: 5.3
Compute the tensile strength of an angle section ISA 100 x 75 x 10mm of Fe
410 grade of steel connected to the gusset plate using fillet weld based on
gross sectional yielding.
(a) 330 kN (b) 622.5kN
(c) 547.8kN (d) 375 kN
Sol:

Student
: 4.
Example: 5.4
A lap joint is used to connect two flat plates of width 220mm and 10mm thickness
with chain pattern bolts having bolt hole diameter 22mm for M20 bolts as shown
in figure. The yield stress and ultimate tensile stress of plate are 250 N/mm2
and
410 N/mm2
respectively. Partial safety factor for material governed by yield
stress and ultimate tensile stress are respectively γmo
=1.10andγm1
= 1.25.
Determine design tensile strength of plate by considering net section rapture.
(a) 277.2 kN (b)315.0 kN
(c) 454.6 kN (d) 502.2 kN
Sol:

7 Tension Members
Student
(c) Design tensile strength based block shear (the block shear strength at end
connection) (Tdb
)
(i) For shear yield and tension fracture:
.
T
A f A f
3
0 9
db
mo
vg y
ml
tn u
1
#
#
#
γ γ
= +
(ii) For shear fracture and tension yield
.
T
A f A f
0 9
3
db
ml
vn u
mo
tg y
2 #
# #
γ γ
= +
where, Avg
and Avn
= minimum gross and net area in shear along a line of
transmitted force, respectively, and Atg
and Atn
= minimum gross and net
area in tension from the hole to the toe of the angle, perpendicular to the
line of force, respectively.
6. Design of Axially loaded Tension member
• In the design of a tension member, the design tensile force is given and
the type of member and the size of the member have to be arrived
at the type of member is usually dictated by the location where the
member is used.
• In the case of roof trusses, angles or pipes are commonly used.
Depending upon the span of the truss, the location of the member in
the truss and the force in the member either single angle or double
angles may be used in roof trusses. Single angle is common in the web
members of a roof truss and the double angles are common in rafter
and tie members of a roof truss.
• Built-up members made of angles, channels and plates are used as
heavy tension members, encountered in bridge trusses.
• The design process is iterative, involving choice of a trial section and
analysis of its capacity.
• The net area required An to carry the factored design load T is
.
A
f
T
or
f
T
0 9
n
m
u
m
u
1 1
# #
γ γ
α
=
• The net area increased by 25% - 40% to compute the gross cross

Student
sectional area calculated by Ag
• Gross area is also determined from its yield strength by A
f
T
g
mo
y
γ
=
• Select a suitable rolled steel section to match with computed gross
area.
• The number of bolts required to make the connection is calculated.
These are arranged in a suitable pattern.
• The design tensile strength of trail section is calculated by considering
h
h Strength in yielding of gross cross section (Tdg
)
h
h Strength in rapture of critical section and (Tdn
)
h
h Strength in block shear (Tdb
)
• The design strength of a trail section Td should be greater than factored
design tensile load
• The slenderness ratio of the member is checked as per IS 800.
7. Maximum or Limiting slenderness ratio (Stiffness Requirement)
• The tension members, in addition to meeting the design strength
requirement, frequently have to be checked for adequate stiffness.
This is done to ensure that the member does not sag too much during
service due to self-weight or the eccentricity of end plate connections.
• Limitations on the slenderness ratio of members subjected to tension
as per IS: 800
Condition for load reversal Limiting or maximum
slenderness ratio
A tension member in which
reversal of direct stress due
to other than wind seismic
loading
180
A member normally
acting as a tie in roof truss
or a bracing system but
subjected to possible of
reversal of stresses resulting
from action of wind or
earth quake forces
350
For any other tension
members (other than pre
tensioned members)
400
Examp

9 Tension Members
Student
le: 5.5.
Example: 5.5
A flat tie 150 ISF 16 is carrying load reversal due to loads other than wind or
seismic loading. Determine maximum length of flat as per IS800.
(a) 1848.0 mm (b) 831.6 mm
(c) 7794.0 mm (d) 1617.0 mm
Sol:
8. Tension Splice
• It is a joint for a tension member, tension splice is provided when
Length of member required is higher than available length from Indian
rolling mills or factory or when two different or same lengths of a
tension member have different thicknesses (or cross section) are to be
connected with filler plate or packing plate
• Tension splices are provided on both sides of member joined in the
form of cover plates.
• The strength of the splice plates and bolts/weld connecting them
should have strength at least equal to design load
• The design shear capacity of bolt carrying shear through packing
plate in excess of 6mm shall be decreased by a factor βpkg

βpkg
= 1.0 - 0.0125 × tpkg
(Where tpkg
= thickness of thicker packing plate in mm)
.6.

Student
Example: 5.6
Two plates 8 mm and 16 mm thick are to be joined by a double cover butt joint
with packing plate and cover plates of 8mm thickness. The effect of packing
on the design shear strength of bolt is multiplied with a factor
(a) 0.10 (b) 0.90 (c) 0.20 (d) 0.80
Sol:
9. Lug Angle
In order to increase the efficiency of the outstanding leg in single angle
tie or outstanding flange of channel in channel tie and to decrease the
length of the end connections, sometimes a short length angle at the ends
are connected to the gusset and the outstanding leg of the main angle
directly or outstanding flange of a channel tie,. Such angles are referred to
as lug angles.
• Lug angle is short length of an angle (or channel) used at a joint to
reduce the length of connection of heavily loaded tension member.
• By using lug angle there will be saving in gusset plate, but additional
fasteners and angle member required, hence now days it is not
preferred.
• IS 800: specifications for lug angle are
h
h The effective connection of lug angle shall as far as possible at
the end of the connection
h
h The connection of lug angle to main member shall preferably
start in advance of the member to gusset plate
h
h Minimum of two bolts or equivalent weld be used for attaching
lug angle to gusset

11 Tension Members
Student
h
h If the main member is an angle
h
h The whole area of the member shall be taken as effective section
rather than net effective section(whole area of the member is
gross area less deduction for bolt holes)
h
h The strength of lug angle and fasteners connection to gusset
plate or any other attachment should be at least 20% (10 %, if
main member is channel) more than the force in outstanding leg.
h
h The strength of fasteners connection lug angle to main member
shall be atleast 40 % more than force carried by the outstanding
leg (20 %, if main member is channel)
Class Room Practice Questions
01. When two angles are used as a tension member, if the angles are not tack
rivet the net tension capacity
(a) Decreases (b) Increases
(c) Remains same (d) none of the above
02. If A1
is the effective cross sectional area of the connected leg and A2
is
gross c/s are of unconnected leg, the net effective area of a single angle
is given by A1
+ K.A2
as per IS800:1984. Where K is equal to
(a)
A A
A
1 2
1
+ (b)
A A
A
3
3
1 2
1
+ (c)
A A
A
5
5
1 2
1
+ (d)
A A
A
3
3
1 2
1
+
03. The allowable tensile stress for a yield stress of ‘fy
’ in structural steel as per
IS800:1984 is
(a) 0.40 fy
(b) 0.45 fy
(c) 0.66 fy
(d) 0.60 fy
04. For a single unequal angle tie member the leg preferred for making
connection is the
(a) Longer one
(b) Shorter one
(c) Any of the two
(d) Longer if riveted and shorter if welded
05. The minimum thickness of steel of the tension members exposed to weather
and not accessible weather as per IS800:1984 is
(a) 4.5mm (b) 6.0 mm
(c) 8.0 mm (d) 10.0 mm

Student
06. Which one of the following values represents the maximum slenderness ratio
of any connection member which normally acts as tie in roof truss but can
be subjected to possible reversal of stress from the action of wind or seismic
loads?
(a) 150 (b) 200 (c) 250 (d) 350
07. Steel of yield strength 400 MPa has been used in structure. What is value of
the maximum allowable tensile strength weather as per IS800:1984?

(a) 240 MPa (b) 200 MPa (c) 120 MPa (d) 96 MPa
08. A steel plate is 300 mm wide and 10mm thick. A rivet of nominal diameter
16mm is driven in to it. The net sectional area of the plate as per IS800:1984
is
(a) 2600 mm2
(b) 2760 mm2
(c) 2830 mm2
(d) 2840 mm2
09. Two equal angles, each being ISA 100 mm × 100 mm of thickness 10 mm,
are placed back-to-back and connected to either side of a gusset plate
through a single row of 16 mm diameter rivets in double shear. The effective
areas of the connected and unconnected legs of each of these angles
are 775mm2
and 950 mm2
respectively. If these angles are not tack-
riveted, the net effective area of this pair of angles as per IS8000:1984 is
(a) 3650 mm2
(b) 3450 mm2
(c) 3076 mm2
(d) 2899 mm2
10. The capacity of single angle ISA 100 mm x100mmx10mm as a tension member
is connected to one leg using 6 rivets of 20 mm diameter as per IS800:1984
is, the allowable stress is 150 N/mm2
(a) 333 kN (b) 253 kN (c) 238 kN (d) 210 kN
11. A steel member ‘M’ has reversal of stress due to live loads, another member
‘N’ has reversal of stress due to wind load. As per IS 800:2007, the maximum
slenderness ratio permitted is.
(a) Lesser for member ‘M’ than that of member ‘N’
(b) More for member ‘M’ than that of member ‘N’
(c) Same for both the members
(d) Not specified in the code

13 Tension Members
Student
12. A member acting as tie in a structure is subjected to possible of reversal
of stresses resulting from loads other than wind or earthquake forces. The
limiting slenderness ration as per IS 800 should not exceed_____
13. The best tension member section will be a
(a) Double angle section on same side of gusset plate with outstanding
legs are tack bolted or welded
(b) Double angle section on same side of gusset plate without outstanding
legs are tack bolted or welded
(c) Double angle section on opposite sides of gusset plate with tack
bolted or tack welded
(d) Double angle section on opposite sides of gusset plate without tack
bolted or tack welded
14. In case of angle section lug angle, their attachment to the main angle
member should capable of developing x% in excess of force in outstanding
leg of the angle, where x is ___
15. What is the effective net sectional area of plate of thickness 10mm as
shown in the given sketch, for carrying tension?
(a) 2125 mm2
(b) 2375 mm2
(c) 2500 mm2
(d) 2750 mm2
16. The design strength of a tension member is governed by
1. Rupture at a critical section
2. Yielding of gross area
3. Block shear of end region
Select the correct answer using the codes given below.
(a) 1 only (b) 2 only (c) 3 only (d) 1,2 and 3

Student
17. Lug angles
(a) Are necessarily unequal angles
(b) Are always equal angles
(c) Increase the shear resistance of joint
(d) Reduce the length of joint
18. A single angle of thickness 10 mm is connected to a gusset by 6 numbers of
18 mm diameter bolt hole, with pitch of 50 mm and with edge distance of
30 mm. The net area in block shear along the line of the transmitted force is
(a) 1810 mm2
(b) 1840 mm2
(c) 1920 mm2
(d) 1940 mm2
KEY for CRPQ
01. (a) 02. (b) 03. (d) 04. (a) 05. (c)
06. (d) 07. (a) 08. (c) 09. (d) 10. (d)
11. (a) 12. (180) 13. (c) 14. (40) 15. (b)
16. (d) 17. (d) 18. (a)
Assignment Questions
01. A Tie is a
(a) Tension member (b) Compression member
(c) Flexural member (d) Biaxial member
02. The maximum spacing of tack bolts for a tension member (where t is the
thickness of thinner member)
(a) 16 t (b) 600 mm (c) 200 mm (d) 1000 mm
03. Lug angle is used at a joint
(a) To increase design tension capacity
(b) To replace tack rivets
(c) To reduce length of joint
(d) To take care of effect of load reversals
04. Single angle member tension welded to gusset is preferred over bolted
angle because
(a) Welded tension member easy to fabricate
(b) Presence of bolt holes weak in tension
(c) Eccentricity of connection can be eliminated by adjusting the weld
length
(d) None of above

15 Tension Members
Student
05. Which one of the following is not a tension member?
(a) Cable (b) Bar (c) Boom (d) Angle
06. In a tension member, when one or more than one rivet hole is off the line
then the failure of plate depends upon
(a) Diameter of rivet hole (b) Pitch of the rivet
(c) Gauge of the rivet (d) All the above
07. A joint in a roof truss, an angle member is connected to a gusset plate with
fillet weld, splitting failure near joint is mode of failure under
(a) Shear force (b) Compressive force
(c) Tensile force (d) Bending due to transverse force
08. Limits are placed on slenderness ratio of tension member
(a) To check the crippling of the member
(b) To limit the buckling of the member
(c) To check the lateral vibration of the member
(d) To check the crookedness of the member
09. A Slenderness ratio in a tension member as per IS 800, where reversal of
load is due to loads other than wind or seismic loads should not exceed
(a) 350 (b) 180 (c) 400 (d) 250
10. Consider the following statements, lug angles are used to
I. Increase the length of the end connection of end connection
II. Decrease the length of end connections of angle section
III. Increase the lengths of the end connection of channel section
IV. Decrease the lengths of end connections of channel section
Which of the following statements are correct?
(a) I & II (b) II & IV
(c) I, III & IV (d) I, II & III
KEY for Assignment Questions
01. (a) 02. (d) 03. (c) 04. (c) 05. (c)
06. (d) 07. (c) 08. (c) 09. (b) 10. (b)

Student
Previous TSPSC & APPSC Questions
01. Net effective area in tension in case of single angle connected by one leg
only is given by: a + kb. The value of k is
(a) 1/ [1+(b/3a)] (b) 1/[1+(a/3b)]
(c) 1/[1+(0.2 b/a] (d) 1/[1+(0.1 b/a)]

02. The maximum permissible slenderness ratio for tension member is
(a) 400 (b) 350 (c) 300 (d) 250
03. The net effective area in case of a single- angle member having the net
connected leg area of 50 mm2
and gross area of unconnected leg as 100
mm2
is
(a) 75 mm2
(b) 130 mm2
(c) 150 mm2
(d) 110 mm2
04. The effective area of 100 ×100 × 6 connected to a gusset plate through one
leg with 20 mm diameter rivets is
(a) 1044.0 mm2
(b) 936.7 mm2
(c) 885.3 mm2
(d) 116.0 mm2
05. Two tension members having different sizes are connected using
(a) Gusset plate (b) Filler plates
(c) Shear legs (d) All of the above
06. The Lug angle is a member which ___ (TSPSC AEE Manager 2015)
(a) is connected to the main tension member to increase its stiffness
(b) is connected to the main tension member for erection purpose.
(c) is connected to the main tension member to increase its strength
locally.
(d) is connected to the main tension member to transfer the tensile force
economically to the joint.
07. Which one is not a possible mode of failure in case of tension members?
(APGENCO Trainee AE-2017)
(a) Yielding of gross section (b) Rupture at the net section
(c) Instability of the element (d) Block shear
KEY for Previous Questions
01. (a) 02. (a) 03. (d) 04. (c) 05. (b)
06. (d) 07. (a)

17 Tension Members
Student
Previous GATE Objective Questions
01. The permissible stress in axial tension in steel member on the net effective
area of the section shall not exceed the following value (fy is the yield stress)
(GATE - 05)
(a) 0.80 fy (b) 0.75 fy
(c) 0.60 fy (d) 0.50 fy
02. In the design of welded tension members, consider the following statements:
(GATE - 06)
I. The entire cross-sectional area of the connected leg is assumed to
contribute to the effective area in case of angles.
II. Two angles back-to-back and tack-welded as per code requirements
may be assumed to behave as a T-section
III. A check on slenderness ratio may be necessary in some cases.
The TRUE statements are
(a) only I and II (b) only II and III
(c) only I and III (d) I, II and III
03. Steel member ‘M’ has reversal of stress due to live loads, where as another
member ‘N’ has reversal of stress due to wind load. As per IS 800:2007, the
maximum slenderness ratio is permitted is.
(1) lesser for member ‘M’ than that of member ‘N’
(2) more for member ‘M’ than for member ‘N’
(3) same for both the members
(4) Not specified in the code (GATE –15–Set 2)
(a) 1 (b) 2 (c) 3 (d) 4
04. Two steel plates each of width 150 mm and thickness 10 mm are connected
with three 20 mm diameter rivets is placed in zig-zag pattern. The pitch of
the rivet is 75 mm and gauge is 60 mm. If the allowable tensile stress is 150
MPa, the maximum tensile force that the joint can withstand is
(GATE - 99)
(a) 195.66 kN (b) 195.00 kN (c) 192.75 kN (d) 225.00 kN
05. ISA 100× 100 × 10 mm (Cross sectional area = 1903 mm2
) serves as tensile
member. This angle is welded to a gusset plate along A and B appropriately
as shown. Assuming the yield strength of the steel to be 260 N/mm2
the

Student
tensile strength of the member can be taken to be approximately
(GATE - 02)
ISA 100×100×10
Gusset Plate
A
B
(a) 500 kN (b) 300 kN (c) 225 kN (d) 375 kN
Common Data for Qs. 06 & 07
A truss tie consisting of 2 ISA 75×75×8 mm carries a pull of 150 kN. At ends
the two angles are connected, one each on either side of a 10 mm thick
gusset plate, by 18 mm diameter rivets arranged in one row. The allowable
stresses in rivet are fs = 90.0 N/mm2 and fbr = 250 N/mm2.
(GATE - 03)
06. Maximum tensile stress in the tie in N/mm2 is
(a) 93.6 (b) 87.5 (c) 77.2 (d) 66.0
07. Minimum number of rivets required at each end is

(a) 2 (b) 3 (c) 4 (d) 5
08. Two equal angles ISA of thickness 10 mm are placed back-to-back and
connected to the either side of a gusset plate through a single row of 16
mm diameter rivets in double shear. The effective areas of the connected
and unconnected legs of each of these angles are 775 mm2 and 950 mm2,
respectively. If these angles are NOT Tack riveted, the net effective area of
this pair of angle is (GATE - 04)
(a) 3650 mm2
(b) 3450 mm2
(c) 3076 mm2
(d) 2899 mm2
09. Two bolted plates under tension with alternative arrangement of bolt holes
are shown in figure 1 and 2. The hole diameter, pitch, and gauge length
are d, p and g respectively. (GATE – 16 – Set 2)
Which one of the following conditions must be ensured to have higher net
tensile capacity of configuration shown in figure 2 than that shown in figure
1?

19 Tension Members
Student
P P
d
Figure 1
P
g P
P
Figure 2
(a) p2
> 2gd (b) p gd
4
<
2

(c) p2
> 4gd (d) p > 4gd
10. A steel flat of rectangular section of size 70 × 6 mm is connected to a gusset
plate by three bolts each having a shear capacity of15 kN in holes having
diameter 11.5 mm. If the allowable tensile stress in the flat is 150 MPa, the
maximum tension that can be applied to the flat is (GATE - 07)
15
20
20
15
T
35
(a) 42.30 kN (b) 52.65 kN
(c) 59.50 kN (d) 63.00 kN
01. (c) 02. (d) 03. (a) 04. (c) 05. (*)
06. (a) 07. (c) 08. (d) 09. (c) 10. (a)

Student
Previous IES - Objective Questions
01. What is the effective net width of plate shown in the given sketch, for carrying
tension? (ESE−1996)

P
Hole dia 25 mm
50
100
100
50
40 50
P
(a) 212.5 mm (b) 237.5 mm
(c) 250 mm (d) 275 mm
02. A singe-angle tie of a welded steel truss in an industrial shed is required to be
designed for an axial tension of 50 kN. If the permissible tensile stress is 150
MPa, then the most suitable section satisfying IS: 800 codal requirements will
be (ESE−1996)
(a) ISA 75 × 50 × 6 (b) ISA 60 × 40 × 5
(c) ISA 50 × 30 × 4 (d) ISA 45 × 30 × 5
03. The slenderness ratio in tension member as per BIS code where reversal of
stress is due to loads other than wind or seismic shall not exceed.
(ESE−2001)
(a) 350 (b) 180
(c) 100 (d) 60
04. The working stress for structural steel in tension is of the order of (ESE−2003)
(a) 15 N/mm2 (b) 75 N/mm2
(c) 150 N/mm2 (d) 750 N/mm2
05. Only a portion of the area of outstanding leg in an angle section serving
as tension member is considered in computing the effective area of the
member. This is because (ESE-2004)
(a) Near the joint, the outstanding leg does not take its full stress
(b) The outstanding leg has a number of rivet holes reducing the net
area

21 Tension Members
Student
(c) The outstanding leg is susceptible to buckling
(d) Additional safety is preferred in the case of tension failure
06. Consider the following statements:
Lug angles are used to (ESE-2004)
1. Increase the lengths of the end connections of angle section.
2. Decrease the length of the end connections of angle section
3. Increase the lengths of the end connections of channel section.
4. Decrease the lengths of the end connections of channel section.
Which of these statements are correct?
(a) 1 and 2 (b) 2 and 4
(c) 1, 3 and 4 (d) 1, 2 and 3
07. A steel rod of 16 mm diameter has been used as a tie in a bracing system,
but may be subject to possible reversal of stress due to the wind. What is the
maximum permitted length of the member? (ESE-2005)
(a) 1600 mm (b) 1400 mm
(c) 1200 mm (d) 1000 mm
08. What is the permissible tensile stress in bolts used for column bases (fy is the
yield stress of the steel)? (ESE-2005)
(a) 120 N/mm2 (b) 150 N/mm2

(c) 0.6fy (d) 0.4fy
09. Lug angles (ESE-2005)
(a) Are necessarily unequal angles
(b) Are always equal angles
(c) Increase the shear resistance of joint
(d) Reduce the length of joint
10. An equal angle of area A has been attached to the support by means of a
lug angle. If allowable stress in tension is f, what is the load carrying capacity
of the member? (ESE-2006)

(a) 0.5fA (b) 0.85fA

(c) 0.9fA (d) 1.0fA
11. What is the maximum slenderness ratio permitted as per IS: 800-1984 for
design of a tie member subjected to reversal of stress due to earthquake?
(ESE-2006)
(a) 180 (b) 250 (c) 300 (d) 350

Student

12. In the case of a tension member consisting of two angles back to back on
the same side of gusset plate, what is k equal to? (Area of connected leg
= A1, Area of outstanding leg = A2) (ESE-2006)
(a)
A A
A
3
3
1 2
1
+ (b)
A A
A
3
3
1 2
1
+ (c)
A A
A
5
5
1 2
1
+ (d)
A A
A
5
5
1 2
1
+
13. Assertion (A): Slenderness ratio of tension members is restricted to 250
Reason (R): Slenderness ratio for tension members is a stiffness criterion
associated with self weight. (ESE-2007)
14. What is the allowable direct tensile stress in structural steel (approximately)?
(ESE-2008)
(a) 0.45fy (b) 0.6fy
(c) 0.66fy (d) 0.80fy
Where fy is the yield stress or proof stress.
15. An equal angle of area A has been welded on one side of a Gusset
plate and carries tension along the axis. What is the effective area of the
angle? (ESE-2008)
(a) 0.5A (b) 0.75A
(c) 0.875A (d) A
16. Steel of yield strength 400 MPa has been used in a structure. What is the
value of the maximum allowable tensile strength? (ESE-2009)
(a) 240 MPa (b) 200 MPa
(c) 120 MPa (d) 96 MPa
17. A tension member consists of two angles placed back to back. For which
one of the following configurations, will the load carrying capacity of the
tension member be maximum? (ESE-2009)
(a) Gusset plate is in between the two angles and tacking rivets are
provided
(b) Gusset plate is in between the two angles and no tacking rivets are
provided
(c) Gusset plate is on one side of the two angles and tacking rivets are
provided
(d) Gusset plate is on one side of the two angles and no tacking rivets are
provided

23 Tension Members
Student
18. Which one of the following values represents the maximum slenderness
ratio of any connection member which normally acts as a tie in a roof truss
but can be subjected to possible reversal of stresses from the action of wind
or seismic force? (ESE-2009)

(a) 150 (b) 200

(c) 250 (d) 350
19. For the roof truss shown in figure below, bottom chord is of ISMB 200
(rx = 83 mm, ry = 22 mm) (ESE-2010)
B
A
E C F D G
X
X
I section XX
6×1.5 =9 m
Bottom chord bracings are available at C and D. Bottom member AE will
be in compression due to wind. What is the critical slenderness ratio used
for the design of member AE?
(a) 18 (b) 36 (c) 68 (d) 136
20. The capacity of a single ISA100×100×10 mm as tension member connected
by one leg only using 6 rivets of 20 mm diameter is
(ESE-2010)
(a) 333 kN (b) 253 kN
(c) 238 kN (d) 210 kN
21. Two equal angles, each being ISA 100 mm ×100 mm of thickness 10 mm
are placed back-to-back and connected to either side of a gusset plate
through a single row of 16 mm diameter rivets in double shear. The effective
areas of the connected and unconnected legs of each of these angles are
775 mm2 and 950 mm2 respectively. If these angles are not tack-riveted,
the net effective area of this pair of angles is
(ESE-2012)
(a) 3650 mm2 (b) 3450 mm2
(c) 3076 mm2 (d) 2899 mm2

Student
22. In the simple system shown in the figure, the load P is equal to 4 tonnes. What
is the tension in the cable. (ESE-2012)

3 m
Cable
1 m
P
3 m 3 m
(a) 4 t (b) 5 t (c) 6 t (d) 7 t
23. Two angles of ISA 100×100×6 mm have been used as a tie member. The
angles are welded on either side of a gusset and tag welded over its length.
The maximum length of the member is:
(For ISA 100×100×6, Area = 2334 mm2
and Yxx
= 30 mm) (ESE−2013)
(a) 5.4 m (b) 6.0 m
(c) 12.0 m (d) 24.0 m
24. A mild steel tube of mean diameter 20 mm and thickness 2 mm is used as an
axially loaded tension member. If fy =300 MPa, what is the maximum load
that the member can carry? (ESE – 2014)
(a) 11.25 kN (b) 22.5 kN
(c) 30.00 kN (d) 37.5 kN
25. The best-suited rolled steel section for a tension member is
(ESE – 2014)
(a) angle section (b) T-section
(c) channel section (d) flat section
26. The design strength of a tension member is governed by
1. Rupture at a critical section
2. Yielding of gross area
3. Block shear of end region
Select the correct answer using the codes given below.
(ESE – 2017)
(a) 1 only (b) 2 only (c) 3 only (d) 1,2 and 3

25 Tension Members
Student
27. Consider the following statements with reference to the design of welded
tension members:
1. The entire cross-sectional area of the connected leg is assumed to
contribute to the effective area in the case of angles
2. Two angles, back –to-back and tack welded as per the codal
requirements, may be assumed to behave as a tee-section.
3. A check on slenderness ratio may be necessary in some cases.
Which of the above statements are correct?
(ESE – 2018)
(a) 1 and 2 only (b) 1 and 3 only
(c) 2 and 3 only (d) 1, 2 and 3
KEY
01.(b) 02.(b) 03.(b) 04.(c) 05.(a) 06.(b) 07.(b) 08.(a) 09.(d) 10.(d)
11.(d) 12.(d) 13.(d) 14.(b) 15.(c) 16.(a) 17.(a) 18.(d) 19.(d) 20.(d)
21.(d) 22.(b) 23.(c) 24.(b) 25.(d) 26.(d) 27.(d)

Unit 2.2 Compression Members
2
COMPRESSION MEMBERS
1. Introduction
• A compression member is a structural member which is subjected
to two equal opposite compressive forces applied at its ends. There
are many types of compression members, the column being the best
known. Top chords of trusses, bracing members, boom is another
principle compression member in a crane and compression flanges
of built up beams and rolled beams are all examples of compression
elements. Columns are usually thought of as straight vertical members
whose lengths are considerably greater than their cross-sectional
dimensions.
• An initially straight strut or column, compressed by gradually
increasing equal and opposite axial forces at the ends is considered
first. Columns and struts are termed “long” or “short” depending on
their proneness to buckling. If the strut is “short”, the applied forces
will cause a compressive strain, which results in the shortening of the
strut in the direction of the applied forces. Under incremental loading,
this shortening continues until the column “squashes”. However, if
the strut is “long”, similar axial shortening is observed only at the initial
stages of incremental loading. Thereafter, as the applied forces are
increased in magnitude, the strut becomes “unstable” and develops
a deformation in a direction normal to the loading axis. The strut is in
a “buckled” state.
• Buckling (mainly in members subjected to compressive forces)
behavior is thus characterized by deformations developed in a
direction (or plane) normal to that of the loading that produces it.
2. General failures in axially loaded columns
• Very short columns subjected to axial compression fail by yielding or
crushing.
• Very long columns fail by elastic buckling in the Euler mode.
• Intermediate columns generally fail by inelastic buckling

27 Compression Members
Student
3. Design compressive strength of a member or section (Pd)
• Slenderness ratio (KL/r) and material yield stress (fy
) are dominant
factors affecting the ultimate strengths of axially loaded compression
members.
Pd
= Ae
× fcd
Where Ae = Effective sectional area
fcd
= Design stress in axial compression
IS:800-2007 proposes multiple column curves
(a, b, c and d) of figure based on Perry Robertson approach

• Code also recommends following equation for estimating design axial
compressive stress (fcd) of axially loaded compression member, it
considers the residual stress, initial imperfection and eccentricity of
load

f
f
f f
.
cd
mo
y
mo
y
mo
y
2 2 0 5 #
φ φ λ
γ
χ γ γ
=
+ −
=
7 A
. .
0 5 1 0 2 2
φ α λ λ
= + - +
^ h
6 @
λ= Non dimensional effective slenderness ratio

/
f
f
f r
KL
E
cc
y
y
2
2
π
= = b l
/
ratio
f
f
f r
KL
E
cc
y
y
2
2
π
= = b l
fcc
= Elastic critical stress =
r
KL
E
2
2
π
b l
r
KL
= Effective slenderness ratio

Student
KL= Effective length of a member
K = Effective length constant
α = Imperfection factor
Buckling class a b c d
Imperfection
factor (α)
0.21 0.34 0.49 0.76
Stress reduction factor account for residual
Stress = x=
1
.
2 2 0 5
φ φ λ
+ −
7 A
γmo
= Partial safety factor for against yield stress
Example: 6.1
A principle strut of a roof truss is composed of two equal angles of ISA 75 x 75 x
6 mm are connected back to back on either side of 10mm thick gusset plate.
The cross sectional area of each angle is 866mm2
and moment of inertia (Izz
=
Iyy
) is 457000 mm4
. The distance of centroid of angle from its surface (Czz
= Cyy
)
is 20.6 mm. The minimum radius of gyration is
(a) 20.6 mm (b) 22.97 mm
(c) 29.22 mm (d) 14.60 mm
Sol:
4. Effective length of Column (KL)
The effective length, KL, is calculated from the actual length (L) of the
member, considering the rotational and relative translational boundary
conditions at the ends.

Student
Boundary Conditions
Schematic representation
Effective
Length (KL)
At one end At the other end
Translation Rotation Translation Rotation
Restrained Restrained Free Free
(Fixed-Free)
2.0L
Restrained Free Free Restrained
(Hinged-Rigid roller)
2.0 L
Restrained Free Restrained Free
(Hinged -Hinged)
1.0L
Restrained Restrained Restrained Free
(Fixed-Hinged)
0.8L
Restrained Restrained Free Restrained
(Fixed-Rigid roller)
1.20L
Restrained Restrained Restrained Restrained
(Fixed -Fixed)
0.65L
L is the unsupported length of the compression member

Student
Exame
Example: 6.2
When the column is effectively held in position and restrained against rotation
at one end and at other end is neither held in position or nor restrained against
rotation, the effective length of column is ‘K’ times unsupported length (L) of
the column, where K is
(a) 1.2 (b) 2.0 (c) 1.5 (d) 0.8
Sol:
5. Effective length for angle struts
Type Section Effective length
In plane of gusset Perpendicular
to gusset
Continuous
angles (top
or bottom
chord
of trusses)
Single angle or double an-
gle
0.7 L to 1.0 L 1.0 L
Single angle connected
with one bolt
1.0 L 1.0 L
Single angle connected
with more than one bolt are
equivalent weld
0.85 L 1.0 L
Double angles placed on ei-
ther side of the gusset plate
0.70 L to 0.85 L 1.0 L
Double angles placed on
same side of the gusset
plate

Example: 6.3.

Student
Example: 6.3
Determine design axial load on column section ISMB 350 given that the height
of column is 3.0 m and that it is pin-ended. Assume fy
=250 MPa, fu
= 410
MPa and E=2x105
MPa (properties of ISMB 350 are A=6670 mm2
, tf
=14.2 mm, tw
= 8.1 mm, b=140mm, h=350mm, rzz
=143 mm & ryy
= 28.4 mm)
(a) 744.23 kN (b) 255.3 kN (c) 766.5 kN (d) 383.5 kN
Sol:

Student
Exe: 6.4.
Example: 6.4
A tubular circular column section is having outer diameter is ‘ d’ and inner
diameter is‘d’. The column is effectively held in position at both ends and
unrestrained against rotation at both ends. The effective slenderness ratio of
column is 200. The L/d ratio of column is
(a) 200 (b) 100 (c) 50 (d) 0
Sol:

6. Buckling class of cross sections

Cross Section Limits
Buckling
about
axis
Buckling
Class
Rolled I-Sections h/bf
> 1.2 :
tf
≤ 40 mm
40 mm < tf
≤
100 mm
z-z
y-y
z-z
y-y
a
b
b
c
h/bf
< 1.2:
tf
≤ 100 mm
tf
>100 mm
z-z
y-y
z-z
y-y
b
c
d
d
Welded I-Section
tf
<40 mm
tf
>40 mm
z-z
y-y
z-z
y-y
b
c
c
d
Hollow Section Hot rolled Any a
Channel, Angle, T and Solid Sections Any c
Built-up Member Any c

Student
7. Maximum slenderness ratio (Stiffness Requirement)
The IS: 800 impose the following limitations on the slenderness ratio of
members subjected to compression
Load Condition
Limiting or
maximum
slenderness
ratio
(a) A member carrying compres-
sive loads from dead and
imposed loads
180
(b) A member subjected to com-
pressive forces resulting only
from combination with wind/
earth quake actions
250
(c) Compression flange of a beam
restrained against torsional
buckling
300
Example6.5.
Example: 6.5
A strut of a roof truss is composed an angles of ISA 60 x 60 x 6 mm are connected
to 10mm thick gusset plate is subjected to compressive loads resulting wind or
earthquake forces. The cross sectional area of each angle is 684mm2
moment
of inertia (Izz
=Iyy
) is 226000 mm4
, Iuu
is 360000 mm4
and Ivv
is 91000 mm4
.Determine
maximum length of strut of a truss as per IS800 is
(a) 2.07 m (b) 4.55 m
(c) 2.88 m (d) 5.72 m
Sol:

Student
8. Built up columns or sections
(a) Used when rolled steel sections do not provide required sectional area
or large radius of gyration of column section is required to different
directions built up section.
(b) Usually provided either lacing or batten system for built up column.
9. Lacing and Battening for built up compression members
(a) The different components of built up sections are placed in such a way
that the built up section has same radius of gyration about both axes.
(i.e. rzz
= ryy
)
(b) The different components of built up sections are connected together
so that they act as a single column.
(c) Lacing and battening systems are used to connect the members.
(d) Lacing is generally preferred in case of eccentric loads. For axially
loaded members, battening is preferred.
10. Lacings for built-up columns
(a) General Specifications
• Flats, angle, channel and tubular sections are used for lacing.
• Lacing system should not be varied throughout the length of the
member.
• The single laced system on opposite sides of the main components
should be in the same direction so that one be the shadow of the
other.
• Tie plates should be provided at the ends of the lacing system and
at points where lacing systems are interrupted.
(b) Design Specifications
• The effective slenderness ratio of laced column should be
increased by 5 % to account for shear deformations due to
unbalance horizontal forces.
• Angle of Inclination (θ) of lacing with longitudinal axis should be
between 40o
and 70o
. (i.e. 40o
≤ θ ≤ 70o
)
• Effective slenderness ratio of lacing bar should not exceed 145.
• Effective length of lacing member (le)
o For single lacing (Bolted) e
, ,
=
o For double lacing (Bolted) .
0 7
e
, ,
=
o For welded lacing .
0 7
e
, ,
=
• For Bolted or welded lacing system,
L/rc
min
≤ 50 or ≤ 0.7 times (KL/r)o
of member as a whole, whichever
is less.
Where,

Student
rc
min
= minimum radius of gyration of the components of
compress member
L
a
V/n
V/2n
V/2n
L
F
F
F
θ
θ
SINGLE LACING
L
a
DOUBLE LACING
θ
θ
• For Bolted or welded lacing system,
L/rc
min
≤ 50 or ≤ 0.7 times (KL/r)o
of member as a whole, which ever
is less.
Where rc
min
= minimum radius of gyration of the components of
compression member
• Minimum width of lacing bar in Bolted connection
Shank diameter of
the bolt (d) in mm
or Nominal diame-
ter of rivet (φ)
22 20 18 16
width of lacing ball 65 60 55 50
Width of lacing bar is approximately 3 x nominal
shank diameter of bolt (d) or Nominal diameter
of rivet (φ)
• Minimum thickness of lacing bar
- tmin
≥ , / 40 for single lacing
- tmin
≥ ,/ 60 for double lacing
Where, , =length of the lacing bar
• The lacing should be designed to resist a transverse shear (V) of
V = 2.5% of design axial column load

Student
(LSD Principle)
V = 2.5% of axial column load (WSM Principle)
• The lacing should be designed to resist additional shear due to
bending if the compression member carries bending
• For single lacing, the force (Design compression or Design tensile)
in each lacing bar,
;
sin
F
N
V
θ
=

sin
F
V
2 θ
= [for double lacing, (N=2)]

sin
F
V
4 θ
= [for double lacing, (N = 4)]
• The effective slenderness ratio of laced builtup column should be
increased by 5% (IS800:2007 specification only)

Example: 6.6
A built up column consists of two ISMC 450 channels placed back to back
carries factored load of 2500 kN, the single lacing provided with an angle 45o
with longitudinal axis should be designed to transverse shear as per IS800:2007
of
(a) 15.0 kN (b) 22.5kN
(c) 62.5kN (d) 44.1 kN
.Sol:

Student
Example: 6.7
A built up column consists of two ISMC 300 channels placed back to back at a
spacing of 200mm and carries working axial load of 1500 kN, the double lacing
provided with an angle 45o
with longitudinal axis. As per IS 800:2007 lacing
member should be designed to resist design axial load of
(a) 22.5 kN (b) 56.3kN
(c) 19.9 kN (d) 39.8 kN
Sol:
11. Batten for built-up columns:
(a) General Specifications:
• The no. of battens should be such that the member is divided into
not less than three parts longitudinally (i.e., minimum 4 batten
plates or minimum two intermediate battens and two end battens)
• Flat plates are used for battens.
• Effective length of battened column should be increased by 10%.
(b) Design Specifications:
• Spacing of battens ‘C’ is such that, the slenderness ratio of
the lesser main component,
r
C
min
c ≯ 50 or 0.7 (KLo
/r) of the
member as a whole about Z-Z axis (parallel to battens), which ever
is less.
C
S
lb
a
b
x
y
x

Student
Where,
rc
min
= minimum radius of gyration of component.
S = transverse distance between centroids of bolt group or rivet group
C = Spacing of battens
lb
= transverse distance between centroids of inner end bolt group or rivet
group
• Battens should be designed to carry bending moment and shear
forces arising from a transverse shear of
V = 2.5% of design axial column load
(LSD Principle)
V = 2.5% of axial column load (WSM Principle)
Longitudinal shear on batten, V1
= VC/NS
Moment on batten, M=VC/2N
Where,
N = No. of parallel plates of battens
= 2 in the above figures.
• Thickness of batten, tb 50
b
,
$
lb
= length of batten plate
• Effective depth of batten
d > 3a/4 for intermediate batten
d > a for end batten
d > 2b for any batten
• Over all depth of batten (D)
D = Effective depth of batten (d) + 2x
edge distance
Working Stress Method Concepts
12. Axial compressive strength (Pc
) of a member:
Pc
= Ae
× σac

Where
Ae
= Effective sectional area of a member,
σac
= Axial allowable compressive stress
IS800:1894 uses Merchant Rankine formula to calculate σac
:

.
.
f f
f f
f
0 6
0 6
/
ac
y
n
cc
n n
y cc
y
1
# #
#
σ =
+
7 A
Where,
fy
= Yield stress of steel
fcc
= Elastic critical stress in compression
= π2
E / [KL/r]2
E = Young’s modulus of steel

Student
KL/r = Slenderness ratio
Minimum radius of gyration of member
Effective length of member
r
KL
min
=
n = a material factor (n = 1.4 for steel)
Minimum radius of gyration about minor axis
/ /
r I A Minimummoment of inertia Area
min
= =
] g
13. Effective length (KL) and allowable axial compressive stress For angle struts,
the specifications as per IS800:1984 are as follows:
End Condition
Effective
length (KL)
Allowable
axial
compressive
stress (σac
)
(a) For discontinuous members
For single rivet
or bolt
1.0 L 0.8σac
For double
rivet Double
bolt & weld
0.85L σac
(b) For Continuous members
For single or
double angle
0.70L
to
0.85L
σac
14. Cased Columns:
• It is necessary to encase the members of steel framed building in
concrete to meet architectural appearance and also increase fire
resistance and check corrosion of steel members
• For designing of cased column, the entire load is assumed to be taken
steel section only and encasement is taken increasing the stiffness of
the column
Specifications of encased columns:
• The member is of symmetrical I-shape or a single I beam, or channels
back to back with or without flange plates.
• The overall dimensions of the steel section do not exceed 750 mm x
450 mm, the large dimension being parallel to web.
• The load carrying capacity of encased column should not exceed 2
times the load permitted on an uncased column.
• The minimum width of solid casing is bo
+ 100 mm, where bo
is the width
of steel flange of column in mm.
• The radius of gyration for encased column (about YY-axis) is given by

Student
ryy
.
ryy
= 0.2 (bo
+ 100) mm
Where,
bo
= width of steel flange in mm;
ryy
is taken as that column of the uncased section.
01. For a circular column section having its ends hinged, the slenderness ratio
is 200. The ratio of l/d of column is
(a) 200 (b) 40 (c) 50 (d) 0
02. In designing of lacing system, a single lacing systems on opposite plans shall
be preferably be in the same direction, so that one is the shadow of the
other is done
(a) To avoid twisting of the built up column section
(b) To avoid bending of the built up column section
(c) To have better architectural appearance built up column section
(d) Connecting the built up columns easily
03. Which of the following statement is/ are true in case of design of lacing
system
1. Angle of inclination of lacing bar with the longitudinal axis in between
40o
- 70o
2. The slenderness ratio (λ) of lacing bar should not exceed 145
3. Lacing system is preferably used for axially loaded columns
4. Flats, angles, channels and tubular section are used for lacing
(a) 1, 2, 3 and 4 (b) 2, 3 and 4
(c) 1 and 2 (d) 1, 2 and 4
04. A Built up column is connected by a single lacing system with 45o
with
longitudinal axis and subjected to a service load of 1000 kN. The lacing
should be designed to resist a transverse shear of
(a) 25.0 kN (b) 50.0 kN
(c) 37.5 kN (d) 75.0 kN
05. Find the design force of lacing member for problem No.04
(a) 17.68 kN (b) 35.60 kN
(c) 13.36 kN (d) 26.52 kN

Student
06. A strut member used in a roof truss consisting of equal angles of ISA
100mm×100mm ×10 mm thick are placed on either sides of 16mm thick
gusset plate. The cross sectional area of angle section is 1903 mm2
and
Moment of inertia is Izz
= Iyy
= 177×104 mm4
then the minimum radius of
gyration is
(a) 50.0 mm (b) 26.8 mm
(c) 30.5 mm (d) 61.0 mm
07. In the design of lacing system for a built up steel column, the maximum
allowable slenderness ratio of a lacing bar
(a) 120 (b) 145
(c) 180 (d) 250
08. The stress reduction factor for an axially loaded compression member
depends upon which of the following factors
I. Residual Stress
II. Initial crookedness
III. Eccentricity of load
IV. Type of cross section
of above factors, the influencing factors is/are
(a) I & II (b) I, II & III
(c) I, II, III & IV (d) III & IV
09. Match list –I (Axially loaded member) with List-II (slenderness ratio) and select
correct answers using the code given below list
List –I
A. For compression members carrying Dead load and live loads
B. For members carrying compressive Due to wind or seismic loads only
C. Compression flange of beam
List-II
1. 180 2. 300 3. 250
Codes:
A B C
(a) 1 2 3
(b) 2 1 3
(c) 2 3 1

(d) 1 3 2

Student
10. A column is effectively held in position and restrained in direction at one,
other end is held in position but not restrained against rotation. If the actual
length is L, the effective length KL is
(a) 0.67L (b) 0.80L
(c) 1.00L (d) 2.00L
11. Consider the following parameters with regards to slenderness ratio of a
compression member:
1. Material
2. Sectional configuration
3. Length of member
4. Support end conditions
On which of these parameters does the slenderness ratio of a compression
member depend?
(a) 1, 2 and 3 only (b) 1, 3 and 4 only
(c) 2, 3 and 4 only (d) 1, 2, 3 and 4
12. Consider the following statements for the design of a laced column:
i. In a bolted construction, the minimum width of the lacing bar shall be
three times the nominal diameter of the end bolt
ii. The thickness of the flat of a single lacing system shall be not less than
one-fortieth of its effective length
iii. The angle of inclination of the lacing bar should be less than 40o
with
the axis of the built-up column
iv. The lacing shall be designed for a transverse shear of 2.5% of the axial
load on the column.
Which of the above statements are correct?
(a) 1, 2 and 3 only (b) 1, 2 and 4 only (c) 1, 3 and 4 only ( d )
1, 2, 3 and 4
13. The slenderness ratio of lacing member should not exceed

(a) 400 (b) 250
(c) 160 (d) 145
KEY for CRPQ
01. (c) 02. (a) 03. (d) 04. (a) 05. (a)
06. (c) 07. (b) 08. (c) 09. (d) 10. (b)
11. (c) 12. (b) 13. (d)

Student
Assignment Questions
01. Which of the following is not a compression member?
(a) Strut (b) Tie
(c) Principle rafter (d) Boom
02. Tubular sections form the most economical compression member
because tubes
(a) Have high lateral buckling strength
(b) Have high torsional resistance
(c) Are subjected to less wind force than any other sections
(d) All the above
03. Which of the following section will be preferred for column section
(a) ISMB (b) ISLB
(c) ISWB (d) ISHB
04. For equal cross sectional area, the most efficient section for column is
(a) I-Section
(b) Channel section
(c) Circular section
(d) Hallow circular section
05. The maximum spacing of tacking bolts for a compression member consists
double angle place back to back on either side of gusset plate is (where
t is the thickness of thinner member)
(a) 12 t (b) 16 t
(c) 600 mm (d) 1000 mm
06. From economical considerations, a built up section column (compound
column section) shall have
(a) ryy
= rzz
(b) ryy
< rzz
(c) ryy
> rzz
(d) ryy
> 2 rzz

Student
07. Four equal angle sections are shown in figure below form a built up column
sections, among these which one will be having higher axial load carrying
capacity.

08. The allowable compressive stress of axially loaded compression member
in IS 800:1984 is given by
(a) Merchant Rankine formula
(b) Secant formula
(c) Euler formula
(d) Perry Robertson formula
09. Minimum number of battens required in built up column is
(a) 4 (b) 3 (c) 5 (d) 2
10. The slenderness ratio of compression member is limited to account for
(a) To effect of accidental and construction loads
(b) They may be used as a walk way in braced roof system
(c) To avoid vibrations
(d) All the above
11. The slenderness ratio of compression member carrying compressive loads
resulting from wind or earthquake actions
(a) 250 (b) 350
(c) 180 (d) 400

Student
12. Which one of the following is the most critical set of consideration in the
design of rolled steel column carrying axial loads?
(a) Percent elongation at yield and net sectional area
(b) Critical bending strength and axial yield strength of the material
(c) Buckling strength based on the net area of the section and percent
elongation at ultimate load
(d) Compressive strength based on slenderness ratio and gross sectional
area of the section
13. Failure in a Long column is generally by
(a) Crushing of material (b) Elastic buckling
(c) Torsional buckling (d) Inelastic buckling
14. Lacing bars in steel built up column are designed to resist
(a) Bending moment resulting from 2.5% column load
(b) Transverse shear force due to 2.5% of axial load in the column
(c) 2.5 % column load
(d) Both (a) and (b)
15. Thickness of lacing flats for single lacing system should not less than x times
length between the inner end bolts, where x is
(a) 1/50 (b) 1/60 (c) 1/3 (d) 1/40
16. For connecting lacing flat to column section with M20 bolts, the minimum
width of flat should be
(a) 36 mm (b) 60mm
(c) 54 mm (d) 65 mm
17. Battens should be designed for moment due to transverse shear of (P:
Axial load on column, N: Number planes of batten, S: Transverse distance
between centroid of bolt group, V: Lateral shear on column)
(a) 2.5%P (b) VC/NS
(c) VC/2N (d) VC/2S
18. The square root of the ratio of moment of inertia of cross section to its
cross sectional area is called
(a) Second moment of area (b) Section modulus
(c) Slenderness ration (d) Radius of gyration

Student
19. The effective length of the member shown in the figure is equal to
(a) 1.2L (b) 1.5L

(c) 2.0L (d) 3.0L
20. A batten plates used to connect the components of built up column are
designed to resist
(a) Longitudinal shear only
(b) Transverse shear only
(c) Longitudinal shear and moment arising from transverse shear
(d) Vertical shear only
21. When the column is supported throughout its length either by masonry
wall or construction on all sides, then its slenderness ratio is
(a) Infinite (b) Zero
(c) Reasonably high (d) Low
22. In laced columns, end tie-plates are provided to
(a) Check the buckling of column
(b) Keep the column components in position
(c) Check the distortion of column sections at ends because of
unbalanced horizontal force from lacings.
(d) Prevent rotation of elements.
23. A column is effectively held in position and restrained in direction at one
end but is free at the other end. If the actual length is L, the effective
length is
(a) 0.67L (b) L
(c) 1.5L (d) 2L

Student
KEY for Assignment Questions
01. (b) 02. (d) 03. (d) 04. (d) 05. (c)
06. (a) 07. (b) 08. (a) 09. (a) 10. (d)
11. (a) 12. (d) 13. (b) 14. (b) 15. (d)
16. (b) 17. (c) 18. (d) 19. (c) 20. (c)
21. (b) 22. (c) 23. (d)
01. The maximum length of a compression member, with minimum radius of
gyration 25mm, carrying both dead and superimposed load as per IS:
800 is
(a) 2.5 m (b) 5.0 m
(c) 4.5 m (d) 7.2 m
02. The minimum thickness of 500 mm long flat double lacing bars is
(a) 10 mm (b) 12 mm (c) 15 mm (d) 8 mm
03. A compression member of length L effectively held in position at both
ends and restrained against rotation at one end will have effective length
(a) 0.65 L (b) 0.80 L (c) 1.0 L (d) 1.20 L
04. Lacing bars in steel column are designed as one of the below indicated
percentage of the axial load of the column
(a) 2.5% (b) 5.0%
(c) 10% (d) 15%
05. In the design of laced column
(i) The slenderness ratio of the lacing bars shall not exceed 145.
(ii) The column is provided with tie plates at the ends.
(iii) Flats only are used as lacing bars.
Of these observations, the correct ones are
(a) (i) and (ii) (b) (i) and (iii)
(c) (ii) and (iii) (d) (i), (ii) and (iii)

Student
06. In case of compression members of constant dimensions, the effective
length in terms of the unsupported length ‘L’ of the member, when the
member is effectively held in position and restrained against rotation at
one end but neither held in position nor restrained against rotation at the
other end is given by
(a) 2 L (b) 1. 5 L
(c) 0.2 L (d) 1.2 L
07. The minimum and maximum angles of inclination of lacing bars to axis of
member are respectively
(a) 30o
and 60o
(b) 40o
and 70o

(c) 45o
and 60o
(d) 60o
and 80o
08. The ratio of maximum horizontal deflection of a column to its length
should not exceed
(a) 2/325 (b) 1/325 (c) 1/225 (d) 2/225
09. A five meter long square column fixed at one end and hinged at the
other has minimum radius of gyration as 100 min; its slenderness ratio is
(a) 50.0 (b) 40.0 (c) 32.5 (d) 20.0
10. The minimum number of battens in a compression steel member is
(a) 4 (b) 6 (c) 8 (d) 3
11. The effective length of a column fixed at one end and restrained against
rotation but not held in position at the other end as a ratio of the actual
length is
(a) 1.0 (b) 1.2 (c) 1.5 (d) 2.0
12. The inclination of a lacing bar with the axis of a compression member
should not be
(a) More than 30o
(b) less than 40o
(c) less than 45o
(d) more than 75o
13. The battens of a column carrying an axial load of 2.5 MN, with two
parallel planes of battens spaced as 1.0 m and 600.0 mm transverse
length should be designed for a transverse shear force of
(a) 62.5 kN (b) 50.0 kN
(c) 31.25 kN (d) 25.0 kN

Student
14. The lateral systems used in built – up columns are
(a) Latticing (b) Stitching
(c) Tacking (d) All of the above
15. The effective length of an angle member in welded joint truss is equal to
(a) L (b) 0.85 L (c) 0.7 L (d) 0.65 L
16. As per IS: 800 – 1984, a cased column should have minimum width of solid
casing equal to (bo is the width of steel flange in mm)
(a) bo
– 100 mm (b) bo
- 50 mm
(c) bo
+ 100 mm (d) bo
+ 50 mm
17. Slenderness ratio of compression member is
(a)
Radius of gyration
Moment of Inertia

(b)
Radius of gyration
Effective length
(c)
sec
Area of cross tion
Radius of gyration
−
(d)
sec
Area of cross tion
Moment of Inertia
−
18. The most economical section for a column is
(a) Hexagonal (b) Rectangular
(c) Tubular section (d) Solid round
19. The ratio of the distance between the innermost connecting lines of rivets
to the thickness of a batten in a steel column should not be
(AEE-2003)
(a) more than 45 (b) less than 45
(c) less than 60 (d) more than 50
20. A compression member is subjected to an axial force of 2000 kN. The
lacings shall be designed to resist a transverse shear of
(TSPSC AEE-2017)
(a) 50 kN (b) 40 kN
(c) 30 kN (d) 20 kN

Student
21. A member under compression is called a
(Lecturers-2013)
(a) tie (b) strut
(c) strut-tie (d) tie –strut
22. The best arrangement to provide unified behaviour in built up steel
columns is by (TS GENCO 2015)
(a) lacing (b) battening
(c) tie plates (d) perforated cover plates
23. When ends of compression members are not faced for complete bearing,
the splices should be designed to transit______ % forces to which they are
subjected. (AE (ENV) Mains-2017)
(a) 25 (b) 100 (c) 50 (d) 75
01. (c) 02. (b) 03. (b) 04. (a) 05. (a)
06. (a) 07. (b) 08. (a) 09. (b) 10. (a)
11. (b) 12. (b) 13. (a) 14. (a) 15. (c)
16. (c) 17. (b) 18. (c) 19. (d) 20. (a)
21. (b) 22. (a) 23. (b)

Unit 2.3 Column Bases and Splices
2
COLUMN BASES AND SPLICES
1. Introduction
The design compressive stress in a concrete footing is much smaller than
it is in a steel column. So it becomes necessary that a suitable base plate
should be provided below the column to distribute the load from it evenly
to the footing below. The main function of the base plate is to spread the
column load over a sufficiently wide area and keep the footing from being
over stressed.
2. Types of Column bases
For a purely axial load, a plain square steel plate or a slab attached to the
column is adequate. For small columns these plates will be shop-welded to
the columns, but for larger columns, it may be necessary to ship the plates
separately and set them to the correct elevations. For this second case the
columns are connected to the footing with anchor bolts that pass through
the lug angles which have been shop-welded to the columns. When there
is a large moment in relation to the vertically applied load a gusseted base
may be required. This is intended to allow the lever arm from the holding
down bolts to be increased to give maximum efficiency while keeping the
base plate thickness to an acceptable minimum.
• Slab base
• Gusseted base
• Grillage Foundation

Student
3. Slab base (Axially loaded columns)
• For a purely axial load, a plain square steel plate or a slab base attached
to the column is adequate.
Foundation bolts
(i) Design procedure of slab base
• Assume a suitable grade of concrete. The bearing strength of concrete is
0.45 fck
(Note: A reduced value of 0.45 fck
is used against maximum of 0.60
fck
as recommended by the code IS 456-2000)
• Required Area of slab base (A)

.
A
DesignBearing strength of concrete
Design axial column load
f
P
0 45 ck
=
• If square base plate is provided

Student
Side of square base plate = L = B = A
If projections of base plate beyond the column faces are a & b are kept
equal
(D+2b) (bf
+ 2a) = A
L = Length of base plate in mm
B = Width of base plane in mm
a = Bigger projection of base plate beyond steel column in mm
b = Smaller projection of base plate beyond steel column in mm
D = Depth of column section in mm
bf
= Width of the flange of column
tf
= Thickness of column flange
w = Upward pressure in N/mm2
on underside of plate assuming a uniform
distribution.
A1
= Area of slab base plate is provided
• The thickness of the slab base (ts
) for I, H, channel, Box section
. .
t
f
w a b
t
2 5 0 3
>
s
y
mo
f
2 2
γ
=
−
^ h
• Holding down 2 or 4 in number and of 20 mm diameter are usually provided,
when base is subjected to only axial compressive load, two bolts will be
enough
Example: 7.1
While designing, for a steel column of Fe410 grade steel base plate resting
on a concrete pedestal of M25 grade, the bearing strength of concrete (in N/
mm2
) as per IS:456-2000 is
(a) 11.25 N/mm2
(b) 9.00 N/mm2
(c) 15.00 N/mm2
(d) 25.00 N/mm2
Sol:
Example 7.2

Student
Example: 7.2
A slab base of size 500mm x 500mm is to be provided below a column section
ISHB250 (Thickness of flange 9.7mm) with width of column flange 250mm
flange supports a design column load 2000 kN. The yield and ultimate tensile
strength of steel are 250 MPa and 410 MPa respectively. The partial safety factor
against yield and ultimate tensile stress are γmo
=1.10 and gm1
=1.25 respectively.
The thickness of slab base is
(a) 9.70 mm (b) 25.82 mm
(c) 33.07mm (d) 31.02 mm
Sol:
4. Gusseted bases (eccentrically loaded columns)
• When there is a large moment in relation to the vertically applied load
a gusseted base may be required.
• Column with gusseted bases, the gusset plates, angle cleats, stiffeners,
fastenings, etc., in combination with the bearing area of the shaft,
shall be sufficient to take the loads, bending moments and reactions
to the base plate without exceeding specified strength.

Student
(i) Design procedure of gusseted base
• Assume a suitable grade of concrete. The bearing strength
of concrete is 0.45 fck
(Note: A reduced value of 0.45 fck
is used
against maximum of 0.60 fck
as recommended by the code)
• Required area of base plate (A)
.
A
DesignBearing strength of concrete
Design axial column load
f
P
0 45 ck
=
• Minimum length of base plate (parallel to the web)
L = Depth of steel column + 2× thickness of gusset plate
+2× leg width of gusset angle + 2× minimum overhang
(for bolted or riveted gusseted bases)
L = Depth of steel column + 2 × thickness
of gusset plate + 2 × minimum overhang
(for welded gusseted base)
• Width of base plate (Normal to the web)

B
Length of base plate
Area of base plate
L
A
=
Steel Column
Gusset plate
Gusset angle
Foundation
bolts
Basic plate
Cleat angle
Concrete pedestal
Riveted or Bolted Gusseted Base

Student
Steel
Column
Gusset
Plate
Base Plate
Gusset
angle
Root of Gusset angle
Gusseted Base
w = Upward pressure in N/mm2
on underside of plate assuming a uniform
pressure distribution under axial load.
w A
P
1
=
• Gusseted base keeps the base plate thickness to be minimum.
• The thickness of Gusseted base is computed by equating the design
bending moment at critical section (i.e. at root of gusset angle) and
equating to moment of resistance of base plate.
• Design bending moment due to upward pressure per mm width at
critical section
M = w c2
/2
• Design bending strength base plate at the critical section Md = 1.2 fy
Z/
γmo
• Thickness of gusseted base . /
t C w f
2 75 y
=
Where,
c = cantilever projection of base plate
(beyond the root of gusset angle in case of bolted gusseted base)
fy
= yield stress of steel in N/mm2
t = Aggregate thickness of base plate and thickness of gusset angle
for bolted or riveted gusseted base and the thickness of base plate for
welded base plate
• The upward pressure from below the base causing the bending of
the gusset plate and puts their top edge in compression which may
therefore buckle. This can be checked by limiting width to thickness
ratio for the gusset plate.
• So
≤ 13.6 ε tg
where ε = /f
250 yg
for the outstand of the gusset plate
where
fyg
= yield stress of gusset plate
tg
= thickness of the gusset plate

Student
Example: 7.3.
Example: 7.3
The thickness of base plate of column base is determined from
(a) Bearing strength of concrete
(b) Flexural capacity of the base plate
(c) Shear capacity of the base plate
(d) Flexural strength of concrete
Sol:
5. Column Splice
• A joint is required in the height of column member in a multistoryed
building frame is called column splice.
• Adopted when the length or height of the column is required more
than the length of column section is available from rolling mills or
factory. Also provided to join two different sizes of steel column cross
sections.
• In case of multistoried building the section column required for various
floors may be different.
• Column splices are designed as a short column.
• Column splices are normally located at section just above the floor
level (h/4 from floor level)

Student
Specifications of column splice
• When the ends of compression member are faced (machined) for
complete bearing over whole area they should be splice to whole the
connected members accurately in position and this is tension if any
bending pressure.
• When such members are not faced (Machine) for complete bearing
splice should designed to transmit all forces to which they are subjected.
Working Stress Method Concepts
1. Types of Column bases:
Three types of column bases are usually provided
• Slab base
• Gusseted base
• Grillage foundation
2. Design of slab base (Design Procedure)
• Assume a suitable grade of concrete. The permissible bearing stress of
concrete is taken as 0.25 fck
A
Permissible bearing stress in concrete
Axial columnload P
c
s
σ
= =
Ps
= working axial column load
• The permissible bearing pressure
(or compressive stress) in concrete is σc
= 4 N/mm2
• The thickness of a square slab base plate as per IS800-1984 is
t
w
a
b
3
4
s
bs
2
2
σ
= −
c m
w = Pressure on underside of base plate
σbs
= Permissible bending stress in slab base
= 185 N/mm2
for all steels
a = Bigger projection of base plate beyond column in mm
b = Smaller projection of base plate beyond column in mm
• The thickness of a square slab base plate under a solid circular column
as per IS800-1984 is
t
w
B d
B
16
90
s
bs o
#
σ
= −
c m

Student
W = the total axial load (kN)
B = the length of side of cap or base in mm
do
= the diameter of the reduced end (if any) of the column in mm
The cap of base plate should not be less than 1.5(do
+75) mm in length or
diameter
3. Design of gusseted base (Design procedure)
• Assume a suitable grade of concrete. The permissible bearing stress of
concrete is taken as 0.25 fck
• Minimum length of base plate
L = Depth of steel column + 2 x thickness of gusset plate + 2 x leg width
of gusset angle + 2 x minimum overhang (for bolted gusseted base)
L = Depth of steel column + 2 × thickness of gusset plate + 2 × minimum
overhang (for welded gusseted base)
• Width of base plate (Normal to the web)
B
Length of base plate
Area of base plate
L
A
=
• The thickness of Gusseted base is computed by equating the design
bending moment at critical section (i.e. at root of gusset angle) and
equating to moment of resistance of base plate.
• Bending moment due to upward pressure per mm width at critical
section
M = w× c2
/2
• Bending strength base plate at the critical section Md
= Z σbs
= 1× t2
×σbs
/6
• Thickness of gusseted base t C
w
3
bs
σ
=
Where,
c = Cantilever projection of base plate
σbs
= Permissible bending stress in slab base
t = Aggregate thickness of base plate and thickness of gusset angle for
bolted or riveted gusseted base and the thickness of base plate for
welded base plate.

Student
4. Grillage foundation (or) grillage footing
top tier beams
• Adopted when steel column carry very heavy loads and the bearing
capacity of the soil is very low.
• It consists of two or more tiers of steel beams placed one above the
other at right angles to each other and embedded in concrete.
• Pipe separators are used to keep the grillage beams properly spaced.
• The distance between edges of adjacent flanges shall not be less than
75 mm.
• Minimum cover of concrete is 100 mm.
• Grillage beam is designed for moment, shear and web crippling
01. Consider following statements regarding gusseted base
I. It is considered to be a pinned base.
II. The gusset material used increases the bearing area consequently
result in smaller thickness of the base plate.
III. The gusset material used supports the base plate against bending and
consequently results in smaller thickness of base plate.
Which one of the following statements is/are correct?
(a) I & II (b) II & III
(c) I & III (d) only II is correct
02. A square steel slab base of area 1m2
is provided for a column made
of two rolled channel sections. The 300mm × 300mm column carries an
axial compressive load of 2000 kN. The line of action of the load passes
through the centroid of the column section as well as of the slab base.
The permissible bending stress in the slab base is 185MPa. The required
minimum thickness of the slab base is
(a) 110mm (b) 89mm
(c) 63mm (d) 55mm

Student
03. Consider the following statements: A grillage base is checked for
1. Bending 2. Shear
3. Compression 4. Web crippling
Which of these statements are correct?
(a) 1 and 4 (b) 1 and 3
(c) 2, 3 and 4 (d) 1, 2 and 4
04. A steel column of Fe410 grade is supported by the base plate and resting
on a concrete pedestal of M20 grade, the bearing strength of concrete (in
N/mm2
) in limit state method of design as per IS:456-2000 is _____
05. A 16 mm thick plate measuring 650 mm× 420 mm is used as a base plate
for an ISHB 300 column subjected to a factored axial compressive load of
2000 kN. As per IS: 456-2000, the minimum grade of concrete that should be
used below the base plate for safely carrying the load is
(a) M15 (b) M20 (c) M30 (d) M40
06. A slab base of 500 mm × 450 mm is to be provided below the column
section ISHB 300@576.86 N/m (Width of flange is 250 mm and thickness of
flange is 11.6 mm). If the bearing pressure from the concrete below the
base plate is 9.0 N/mm2
and yield stress of plate is 250 Mpa. The minimum
thickness of slab base is required as per IS 800:2007 is_____mm.
KEY for CRPQ
01. (b) 02. (d) 03. (d) 04. (9) 05. (b)
06. 26.3
Objective Questions
01. In case of axially loaded column machined for full bearing, the fastenings
connecting the column to base plate in gusseted base are designed for
(a) 100 % column load
(b) 50 % column load
(c) 25 % column load
(d) Erection load only

Student
02. The thickness of the base plate determined from the
(a) Flexural strength of the plate
(b) Shear strength of the plate
(c) Bearing strength of concrete pedestal
(d) Punching criteria
03. In a gusseted base, the critical section for considering the thickness of base
plate is
(a) At centre of base plate
(b) At edge of the base plate
(c) At root of gusset angle
(d) At C.G of gusset angle
04. In a gusseted base, when the end of the column is machined smooth for
complete bearing, the axial load is transferred to base slab
(a) fully through fastening
(b) fully by direct bearing
(c) 50% by direct bearing and 50% through fastening
(d) 60% by direct bearing and 40% through fastening
KEY for Objective Questions
01. (b) 02. (a) 03. (c) 04. (c)
01. A square column of size 300 mm supposing 2.0 MN load is provided with a
square base plate of 500 mm. The minimum thickness of base plate, for a
permissible bending stress of 200 MPa is
(a) 30 mm (b) 20 mm
(c) 10 mm (d) 8 mm
02. Match list-I (column base) with list-II (its application) and select correct
answers using the code given below
List-I
A) Grillage foundation
B) Gusseted base
C) Slab base

Student
List-II
1) Lightly axial loaded steel column
2) Heavy loaded steel column to be rested on weak soils
3) Eccentric loaded steel column
Codes:
A B C
(a) 1 2 3
(b) 2 1 3
(c) 2 3 1
(d) 3 2 1
03. The main function of Column base is to
(a) resist the Deflections
(b) transmit the Column load to foundation
block
(c) resist lateral forces
(d) reduce the effect of vibration
04. The main function of Column base is to (TSPSC AEE 2015)
(a) resist the Deflections
(b) transmit the Column load to foundation block
(c) resist lateral forces
(d) reduce the effect of vibration
05. The thickness of the column base plate is determined from
(APGENCO Trainee AE-2017)
(a) Shear strength of the plate (b) Flexural strength of the plate
(c) Punching shear strength (d) Bearing strength of the plate
06. The expression working out the thickness of slab base is given by ______. If t
= thickness of slab base, w = pressure under slab base,
σbs
= permissible bending stress in slab base, a, b = longer and shorter
projections of the slab base edge to the column member, Poisons ratio =
0.25
(TSPSC AEE Manager 2015)
(a) t = ((3w/σbs
)(a–b2
/4))1/2
(b) t = ((3w/σbs
)(a2
–b2
/4))1/2

(c) t = ((3w/σbs
)(a2
–b2
))1/2
(d) t = ((3w/σbs
)(a–b/4))1/2

Student
01. (a) 02. (c) 03. (b) 04. (b) 05. (b)
06. (b)
Previous GATE - Objective Questions
01. In the design of lacing system for a built-up steel column, the maximum
allowable slenderness ratio of a lacing bar is ` (GATE - 03)

(a) 120 (b) 145
(c) 180 (d) 250
02. Consider the following statements
I. Effective length of a battened column is usually increased to account
for the additional load on battens due to the lateral expansion of
columns.
II. As per IS: 800-1984, permissible stress in bending compression depends
on both Euler buckling stress and the yield stress of steel.
III. As per IS: 800-1984, the effective length of a column effectively held in
position at both ends but not restrained against rotation, is taken to be
greater than that in the ideal end conditions.
The TRUE statements are (GATE - 06)
(c) only I and III (d) I, II and III
03. Consider the following statements for a compression member
I. The elastic critical stress in compression increases with decrease in
slenderness ratio
II. The effective length depends on the boundary conditions at its ends
III. The elastic critical stress in compression is independent of the
slenderness ratio
IV. The ratio of the effective length to its radius of gyration is called as
slenderness ratio
The TRUE statements are
(c) only I and III (d) I, II and IV

Student
04. The square root of the ratio of moment of inertia of the cross-section to its
cross-sectional area is called (GATE - 09)
(a) second moment of area (b) slenderness ratio
(c) section modulus (d) radius of gyration
05. Two steel columns P (length L and yield strength fy = 250 MPa) and Q (length
2L and yield strength fy = 500 MPa) have the same cross-sections and end-
conditions. The ratio of buckling load of column P to that of column Q is:
(GATE - 13)
(a) 0.5 (b) 1.0 (c) 2.0 (d) 4.0
06. Consider the following two statements related to structural steel design,
and identify whether they are True or FALSE.
I. The Euler buckling load of a slender steel column depends on the yield
strength of steel.
II. In the design of laced column, the maximum spacing of the lacing
does not depend on the slenderness of column as a whole.
(GATE - 01)
(a) Both statements I and II are TRUE
(b) Statement I is TRUE, and Statement II is FALSE
(c) Statement I is FALSE, and Statement II is TRUE
(d) Both Statements I and II are FALSE
07. A strut in a steel truss is composed of two equal angles ISA of thickness 100
mm connected back-to-back to the same side of a gusset plate. The cross
sectional area of each angle is 2921 mm2 and moment of inertia (Ixx = Iyy)
is 6335000 mm4. The distance of the centroid of the angle from its surface
(Cxx = Cyy) is 40.8 mm. The minimum radius of gyration of the strut is
(GATE - 04)
(a) 93.2 mm (b) 62.7 mm
(c) 46.6 mm (d) 29.8 mm
08. A compound steel column consisting of 2 ISHB 400 placed at 320 mm
centers, carries a total axial load of 2500 kN. Minimum slenderness ratio of
the compound column is 30. Width of the flange of one ISHB section is
250 mm and its minimum radius of gyration is 51.6 mm. Design a suitable
single flat lacing. 20 mm diameter single rivet is used to connect the lacings
to the column. Rivet capacity need not be calculated. The following table
may be used. (GATE - 97)

Student
Slenderness ratio
Stress N/mm2
Permissible compressive
100 8
110 71
120 64
130 57
140 51
150 45
09. Given reason for the following is not more than 20 words
(GATE - 02)
(a) A maximum permissible distance between lacing and battens in steel
columns is usually specified.
(b) It is sometimes preferable to have unequal flange angle with the longer
legs horizontal in plate girder.
(c) If two channel sections need to be used as a steel column, they may
be connected ‘face-to-face’ rather than ‘back-to-back’
(d) It is sometimes preferred to have a small gap between the web and
the flange plate in a plate girder.
(e) A maximum permissible ‘outstand may be specific for flange in built-up
sections.
KEY for Previous GATE Questions
01. (b) 02. (a) 03. (d) 04. (d) 05. (d)
06. (d) 07. (c) 08. (150 N/mm2) 09. (*)

Student
Previous IES - Objective Questions
01. In the case of an axially loaded column machined for full bearing, the
fastenings connecting the column to the base plates in gusseted base are
designed for (ESE−1998)
(a)100% of the column load (b) 50% of the column load
(c) 25% of the column load (d) Erection conditions only
02. Consider the following statements:
A grillage base is checked for
1. Bending 2. Shear
3. Compression 4. Web crippling
Which of these statements are correct? (ESE−1999)
(a) 1 and 4 (b) 1 and 3
(c) 2, 3 and 4 (d) 1,2 and 4
03. The moment rotation curve shown in the given figure is that of a
(ESE−1999)
Rotation
Moment
O
(a) Rigid joint (b) flexible joint
(c) Pin joint (d) semi-rigid joint
04. Which one of the following plan views of a gusseted base plate will result in
minimum base plate thickness? (ESE−2000)

140 mm
400 mm
600
mm
600 mm
(a)

400
mm
(b) 140 mm
600 mm
600
mm

Student

140 mm
400 mm
500
mm
720 mm
(c)

(d)
140 mm
400 mm
500
mm
720 mm
05. The type of stress induced in the foundation bolts fixing a column to its
footings is (ESE− 2003)
(a) Pure compression (b) Bearing
(c) Pure tension (d) Bending
06. Where should splices in the columns be provided? (ESE-2005)
(a) At the floor levels
(b) At the mid height of columns
(c) At the beam-column joints
(d) At one-fourth height of columns
07. In a gusseted base, when the end of the column is machined smooth for
complete bearing, the axial load is transferred to base slab (ESE-2005)
(a) Fully through fastening
(b) Fully by direct bearing
(c) 50% by direct bearing and 50% through fastening
08. In a gusseted base, when the end of the column in machined for complete
bearing on the base plate, the axial load is assumed to be transferred to
the base plate (ESE-2007)
(a) fully by direct bearing
(b) fully through the fastenings
(c) 50% by direct bearing and 50% through fastenings
09. The base plate of a roof truss is attached to the concrete pier with the
help of 16 mm diameter mild steel anchor bolts of grade fy = 250 MPa.
What is the maximum pull the base can be subjected to, if the root area of
bolt = 0.75 times shank area? (ESE-2010)
(a) 30 kN (b) 67.5 kN (c) 90 kN (d) 120 kN

Student
10. Consider the following statements in respect of column splicing:
1. Splices should be provided close to the point of inflection in a member
2. Splices should be located near to the point of lateral restraint in a
member
3. Machined columns for perfect bearing would need splices to be
designed for axial force only
Which of the above statements are correct? (ESE – 2018)
(a) 1 and 2 only (b) 1 and 3 only (c) 2 and 3 only (d) 1, 2 and 3
KEY for Previous IES - Objective Questions
01. (b) 02. (d) 03. (d) 04. (b) 05. (c)
06. (d) 07. (c) 08.(c) 09. (a) 10. (b)
Previous JNTU - Questions
01. Distinguish between lacing and battening.
02. Design a column having an effective length of 6m and subjected to
a factored axial load of 2400 kN. Provide the channels back-to-back
connected by welded lacing. Assume Fe410 grade steel.
03. A column ISHB350@661.2 N/m carries an axial compressive factored load
of 1700 kN. Design a suitable welded gusset base. Assume M20 grade
concrete.
04. Define slenderness ratio?
05. What is strut? What are the common sections used as strut?
06. Design a double angle discontinuous strut to carry a factored load of
135 kN. The length of strut is 3m between intersections. two angles are
placed back-to-back (with long legs are connected) and are tack bolted.
Use steel grade Fe410.
a) Angles are placed on opposite side of 12 mm gusset plate.
b) Angles are placed on same side of 12 mm gusset plate.
07. Design a single angle strut for a roof truss carrying a compressive load of
80 kN. The length of strut between centre to centre is 354cm. Also design
the welded connection.
08. State four standard support conditions of compression members and state
corresponding expressions for effective length.
09. Design a column having an effective length of 6m and subjected to
a factored axial load of 2400 kN. Provide the channels back to back
connected by welded battens. Assume Fe410 grade steel. Sketch the
details of the section.

Student
10. Design a slab base for a column ISHB 350 carrying an axial factored load
of 1200 kN. M25 concrete is used for the foundation. Provide welded
connection between column and base plate. Sketch the column base.
Sketch the details of the section.
11.
a) Explain the different modes of tension failure.
b) Design a tension member to carry a factored force of 340kN. Use
20mm dia black bolts and a gusset plate of 8 mm thick.
12. Design a gusseted base to carry an axial factored load of 3000kN. The
column is ISHB 450@855 N/m with two 250X22 mm cover plates on either
side. The effective height of the column is 5m. The column is to rest on M20
concrete pedestal. Sketch the details of the gusset base.
Previous JNTU - Objective Questions
01. The effective length of a battened column is increased by
(a) 5% (b) 10% (c) 15% (d) 20%
02. The slenderness ratio of a column supported throughout its length by a
masonry wall is
(a) zero (b) 10 (c) 100 (d) infinity
03. The best arrangement to provide unified behaviour in built up steel columns
is by
(a) lacing (b) battening
(c) tie plates (d) perforated cover plates
04. Battening is preferable when the
(a) column carries axial load only
(b) space between the main components is not large
(c) Both column carries axial load only & space between two main
components is not large
(d) none
05. Buckling of column means
(a) Lateral deflection (b) Axial deflection
(c) Torsional deflection (d) None of the listed
(a) 10% (b) 15% (c) 20% (d) 5%
07. For equal cross section area, the most efficient as a column is
(a) I-section (b) channel section (c) circular (d) Hollow circular
08. The maximum slenderness ratio of compression member carrying both
dead and superimposed load is
(a) 180 (b) 200 (c) 250 (d) 350

Student
09. The approximate allowable average shear in MS standard section is
(in Mpa) ________
(a) 85 (b) 100 (c) 130 (d) 75
10. For a circular column having its ends hinged, the slenderness ratio is 160.
The I/d ratio of the column is
(a) 80 (b) 57 (c) 40 (d) 20
(a) 10% (b) 15% (c) 20% (d) none
12. The maximum permissible slenderness ratio for the tension members is
(a) 400 (b)350 (c) 300 (d) 250
13. The maximum spacing of tack rivets for a tension member is
(a) 160 mm (b) 200 mm (c) 600 mm (d) 1000 mm
14. In a bracket plate to column connection, if the plane of loading is
perpendicular to the plane of connection the bolts are subjected to
(a) Shear only (b) Shear and tension
(c) Shear and Compression (d) Only bearing
15. The maximum slenderness ratio of steel column subjected to dead and live
loads alone is
(a) 200 (b) 180 (c) 300 (d) 150
16. For a tension member in a roof truss subjected to possible reversal of stress,
the slenderness ratio is limited to ______
(a) 250 (b) 350 (c) 300 (d) 200
17. The maximum deflection allowed in steel compression members in ordinary
steel building is
(a) L/325 (b) L/250 (c) L/450 (d) L/540
18. The effective slenderness ratio (KL/r)e
of laced columns shall be taken as
_____ times (KL/r)o
(a) 1.5 (b) 1.15 (c) 1.05 (d) 1.25
19. In bolted/riveted construction, the minimum width of lacing bars shall be
________ times the nominal diameter of the end bolt/rivet.
(a) 2 times (b) 3 times (c) 2.5 times (d) 4 times
KEY for JNTU - Objective Questions
01. (b) 02. (a) 03. (a) 04. (c) 05. (d)
06. (a) 07. (d) 08.(a) 09. (b) 10. (c)
11. (a) 12. (a) 13.(d) 14. (b) 15. (b)
16. (b) 17. (a) 18.(c) 19. (b)

Student

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