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)
Correct Answer :
A. fc = π²E/(I/r)²
Related Questions
Number of rivets required in a joint, is
Load/Shear strength of a rivet
Load/Bearing strength of a rivet
Load/Tearing strength of a rivet
Load/Rivet value
The permissible stress to which a structural member can be subjected to, is known as
Bearing stress
Working stress
Tensile stress
Compressive stress
Which of the following sections should preferably be used at places where torsion occurs?
Angle section
Channel section
Box type section
Any of the above
For a steel member of slenderness ratio 350, the allowable stress is 76 kg/cm2 if it is
HTW grade of thickness exceeding 32 mm
HT grade of thickness exceeding 45 mm
HT grade of thickness not exceeding 45 mm
All the above
When a load is transferred through one surface to another surface in contact, the stress is known as
Tensile stress
Compressive stress
Shearing stress
None of these
Pick up the correct statement from the following:
When the gauge distance is larger than the pitch, the failure of the section may occur in a zig-zag line
When the gauge distance is smaller than the pitch, the failure of the section may occur in a straight right angle section through the centre of rivet holes
When the gauge distance and pitch are both equal, the failure to the section becomes more likely as the diameter of the holes increases
All the above
As per ISI, rolled steel beam sections are classified into
Two series
Three series
Four series
Five series
Pitch of tacking rivets, when double angles connected back to back and acting as tension members should not be more than
500 mm
600 mm
1000 mm
300 mm
Column footing is provided
To spread the column load over a larger area
To ensure that intensity of bearing pressure between the column footing and soil does not exceed permissible bearing capacity of the soil
To distribute the column load over soil through the column footing
All the above
When plates are exposed to weather, tacking rivets are provided at a pitch in line not exceeding (where t is the thickness of the outside plate).
8 t
16 t
24 t
32 t
When a tension member is made of four angles with a plate as a web, the allowance for holes is made as
Two holes for each angle and one hole for the web
One hole for each angle and one hole for the web
One hole for each angle and two holes for the web
Two holes for each angle and two holes for the web
The main assumption of the method of simple design of steel frame work, is:
Beams are simply supported
All connections of beams, girders and trusses are virtually flexible
Members in compression are subjected to forces applied at appropriate eccentricities
All the above
The least permissible clear dimension of the web of thickness t in the panel of a plate girder, is restricted to
150 t
160 t
170 t
180 t
Maximum permissible slenderness ratio of a member normally acting as a tie in a roof truss, is
180
200
250
350
For a steel grillage footing to support two unequal column loads
Line of action of the resultant of two column loads, is made to coincide with the centre of gravity of the base of the footing
Trapezoidal shape is used for the base footing
Projections of beams on either side in lower tier are such that bending moments under columns are equal
All the above
The critical load for a column of length I hinged at both ends and having flexural rigidity El, is given by
Pc = π²EI/l²
Pc = πEI/l²
Pc = πEI/I²
None of these
Rise of a Jack arch is kept about
1/2 to 1/3 of the span
1/3 to 1/4 of the span
1/4 to 1/8 of the span
1/8 to 1/12 of the span
The greatest permissible clear dimension of the web of thickness t in the panel of a plate girder, is restricted to
180 t
220 t
230 t
270 t
Strengths of a rivet in single shearing, in bearing and in tearing are 3425 kg, 4575 kg and 5025 kg respectively. If the load in the member is 35 tonnes, the number of rivets required, is
10
11
12
13
The slenderness ratio of a column supported throughout its length by a masonry wall is
Zero
10
100
Infinity
Slenderness ratio of a compression member is
Moment of inertia/Radius of gyration
Effective length/Area of cross-section
Radius of gyration/Effective length
Radius of gyration/ Area of cross-section
Minimum pitch of the rivets shall not be less than
1.5 d
2.0 d
2.5 d
3.0 d Where d is gross diameter of rivet
The maximum permissible span of asbestos cement sheets is
650 mm
810 mm
1250 mm
1680 mm
As per IS: 800, in the plastic design, which of the following pairs are correctly matched?
Working Loads Load factor
(i) Dead load 1.7
(ii) Dead Load + imposed load 1.7
(iii) Dead load + load due to wind or 1.3 seismic forces
(iv) Dead load + imposed load + load 1.7 due to wind or seismic forces
Of these statements
(i) and (ii) are correct
(i), (ii) and (iii) are correct
(ii) and (iii) are correct
Only (i) is correct
For a cantilever beam of length L continuous at the support and unrestrained against torsion at the support and free at the end, the effective length l is equal to
l = L
l = 2L
l = 0.5L
l = 3L
The greatest gauge of long rivets should not exceed (where d is the diameter of the holes).
2 d
4 d
6 d
8 d
A major beam in a building structure, is known as
A girder
A floor beam
A main beam
All the above
The elastic strain for steel is about
1/12 of strain at the initiation of strain hardening and about 1/120 of maximum strain
1/2 of strain at the initiation of strain hardening and about 1/12 of maximum strain
1/12 of strain at the initiation of strain hardening and 1/200 of maximum strain
1/24 of strain at the initiation of strain hardening and about 1/200 of maximum strain
If d is the distance between the flange angles, the vertical stiffeners in plate girders without horizontal stiffeners, are spaced at a distance not less than
0.15 d
0.22 d
0.33 d
0.44 d
The main type of butt joints, is a double cover
Shear riveted joint
Chain riveted joint
Zig-zag riveted joint
All the above