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
Correct Answer :
A. Transfer load from top of end posts to bearings
Related Questions
For the buildings having a low permeability, the internal wind pressure acting normal to the wall and roof surfaces is taken as
Zero
±0.2 p
± 0.5 p
±0.7 p Where p is basic wind pressure
In plastic analysis, the shape factor for circular sections, is
1.5
1.6
1.697
None of these
Net sectional area of a tension member, is equal to its gross section area
Plus the area of the rivet holes
Divided by the area of rivet holes
Multiplied by the area of the rivet holes
None of these
Rolled steel angle sections are classified as
Equal angles
Unequal angles
Bulb angles
All the above
Steel tanks are mainly designed for
Weight of tank
Wind pressure
Water pressure
Earthquake forces
Pick up the correct statement from the following:
Loaded columns are supported on column bases
Column bases transmit the column load to the concrete foundation
Column load is spread over a large area on concrete
All the above
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
The permissible stress in bending for rolled steel I-beams and channels, is
1500 kg/cm2
1575 kg/cm2
945 kg/cm2
1650 kg/cm2
If P is the wind pressure in kg/cm2, v is the velocity in km/hour and K is a constant of proportionality, then
P = K/v2
v = K/P2
P = Kv2
P = Kv
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)
When the upper column does not provide full bearing area over lower column, the column splice is provided with the following assumption
Bearing plate is assumed as a short beam to transmit the axial load to the lower column section
Axial load is assumed to be taken by flanges
Load transmitted from the flanges of upper column and reactions from the flanges of lower columns are equal and form a couple
All the above
The beam outside a wall upto floor level above it, is known as
Rafter
Purlin
Spandrel beam
Lintel
The best arrangement to provide unified behaviour in built up steel columns is by
Lacing
Battening
Tie plates
Perforated cover plates
The most commonly used sections in lateral system to carry shear force in built up columns, are
Rolled steel flats
Rolled angles
Rolled channels
All the above
If the depth of the section of an upper column is smaller than the lower column
Filler plates are provided with column splice
Bearing plates are provided with column splice
Filler plates and bearing plates are provided with column splice
None of these
The maximum permissible slenderness ratio of compression member carrying dead and superimposed load, is
180
200
250
350
If the 20 mm rivets are used in lacing bars, then the minimum width of lacing bar should be
40 mm
60 mm
80 mm
100 mm
Live load
Varies in magnitude
Varies in position
Is expressed as uniformly distributed load
All the above
According to the Unwin's formula, if t is thickness of the plate in mm, the nominal diameter of the rivet, is
d = 1.91 t
d = 1.91 t2
d = 1.91 √t
d = 1.91 t
In a gusseted base, when the end of the column is machined for complete bearing on the base plate, then the axial load is assumed to be transferred to base plate
Fully by direct bearing
Fully through fastenings
50% by direct bearing and 50% through fastenings
75% by direct bearing and 25% through fastenings
The bending moment for filler joists at the middle of an intermediate span, is
WL²/10
- WL²/10
- WL²/12
WL²/12
The ratio of shearing stress to shearing strain within elastic limit, is known as
Modulus of elasticity
Shear modulus of elasticity
Bulk modulus of elasticity
Tangent modulus of elasticity
The distance between e.g. of compression and e.g. of tension flanges of a plate girder, is known as
Overall depth
Clear depth
Effective depth
None of these
The Indian standard code which deals with steel structures, is
IS : 875
IS : 800
IS : 456
IS : 1893
The minimum edge distance of a rivet line connecting two or more plates, is kept equal to 37 mm plus (where t is the thickness in mm of the thinner outside plate).
2 t
4 t
6 t
8 t
Tongue plates are provided in a steel girder at
The upper flange
The lower flange
The upper end of the web
The upper and lower ends of the web
Outstanding length of a compression member consisting of a channel, is measured as
Half of the nominal width
Nominal width of the section
From the edge to the first row of rivets
None of these
According to IS Specifications, the effective length of a column effectively held in position at both ends and restrained in direction at one end is taken as
0.67 L
0.8 L
L
1.5 L
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