The range of economical spacing of trusses varies from
L/3 to L/5
L/4 to 2L/5
L/3 to L/2
2L/5 to 3L/5, where L is span
Correct Answer :
A. L/3 to L/5
Related Questions
Area of openings for buildings of large permeability is more than
10% of wall area
20% of wall area
30% of wall area
50% of wall area
The effective length of a compression member of length L, held in position and restrained in direction at both ends, is
L
0.67 L
0.85 L
1.5 L
Select the correct statement
Material cost of a rivet is higher than that of a bolt
Tensile strength of a bolt is lesser than that of a rivet
Bolts are used as a temporary fastening whereas rivets are used as permanent fastenings
Riveting is less noisy than bolting
Intermediate vertical stiffeners in a plate girder need be provided if the depth of web exceeds
50 t
85 t
200 t
250 t Where t is thickness of web
The actual thickness of butt weld as compared to the thickness of plate is usually
More
Less
Equal
None of the above
If W and L are the total superimposed load and the span of a plate girder in metres, the approximate self weight (W) of the girder, is taken as
M = WL/100
M = WL/200
M = WL/300
M = WL/400
The maximum axial load which is just sufficient to keep a column in a small deflected shape, is called
Crippling load
Buckling load
Critical load
All the above
Long column is one
Which is more than 3 m long
Whose lateral dimension is less than 25 cm
Which is free at its top
Which has a ratio of effective length and least lateral dimension more than 15
The thickness t of a single flat lacing should not be less than
1/30th length between inner end rivets
1/40th length between inner end rivets
1/50th length between inner end rivets
1/60th length between inner end rivets
The effective length of a compression member of length L held in position at both ends but not restrained in direction, is
L
0.67 L
0.85 L
1.5 L
For a compression member with double angle section, which of the following section will give larger value of minimum radius of gyration?
Equal angles back to back
Unequal legged angles with long legs back to back
Unequal legged angles with short legs back to back
Both (B) and (C)
As compared to field rivets, the shop rivets are
Stronger
Weaker
Equally strong
Any of the above
The minimum width B of a solid casing for a cased beam, is equal to
B = b + 25 mm
B = b + 50 mm
B = b + 75 mm
B = b + 100 mm
Shape factor is a property which depends
Only on the ultimate stress of the material
Only on the yield stress of the material
Only on the geometry of the section
Both on the yield stress and ultimate stress of material
The allowable stress in axial tension for rolled I-sections and channels, is taken as
1420 kg/cm2
1500 kg/cm2
2125 kg/cm2
1810 kg/cm2
The permissible bearing stress in steel, is
1500 kg/cm2
1890 kg/cm2
2025 kg/cm2
2340 kg/cm2
The portal bracing in a truss bridge is used to
Transfer load from top of end posts to bearings
Keep the rectangular shape of the bridge cross-section
Stiffen the structure laterally
Prevent the sides-way buckling of top chord
In the virtual work method, the virtual quantity is
Displacement
Load
Slope
Moment
The permissible stress to which a structural member can be subjected to, is known as
Bearing stress
Working stress
Tensile stress
Compressive stress
The channels get twisted symmetrically with regard to its axis
Parallel to flanges
Parallel to web
Perpendicular to flanges
Perpendicular to web
For the economical design of a combined footing to support two equal column loads, the projections of beams in lower tier are kept such that bending moment under column is equal to
Bending moment at the centre of the beam
Half the bending moment at the centre of the beam
Twice the bending moment at the centre of the beam
None of these
In double lacing, the thickness t of flat lacing is
t < 1/40 th length between inner end rivets
t < 1/50 th length between inner end rivets
t < 1/60 th length between inner end rivets
t < 1/70 th length between inner end rivets
When a large value of radius of gyration is not required
Channels are placed back to back
Channel flanges are kept inward
Channel flanges are kept outward
None of these
Minimum spacing of vertical stiffeners is limited to
d/4
d/3
d/2
2d/3 Where d is the distance between flange angles
In rolled steel beams, shear force is mostly resisted by
Web only
Flanges only
Web and flanges together
None of these
The critical stress on a column for elastic buckling given by Euler's formula, is
fc = π²E/(I/r)²
fc = (I/r)²/ πE
fc = (I/r)/ πE
fc = π²E/(I/r)
The effective length of a battened column is increased by
5 %
10 %
15 %
20 %
On steel structures the dead load is the weight of
Steel work
Material fastened to steel work
Material supported permanently
All the above
Maximum permissible slenderness ratio of a member normally acting as a tie in a roof truss, is
180
200
250
350
According to IS: 800, in the Merchant Rankine formula the value of imperfection index (n) is
1.0
1.4
1.8
2.0