If L is the overall length of a combined footing having A as its area, d being the distance between the centre of gravity of the base and centre of the base, the larger width b is
(A/L) + (3Ad/L²)
(A/L) + (6Ad/L²)
(A/L) - (6Ad/L²)
(A/L) - (3Ad/L²)
Correct Answer :
B. (A/L) + (6Ad/L²)
Related Questions
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
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 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
For rivets in tension with countersunk heads, the tensile value shall be
Reduced by 25 %
Reduced by 33.3%
Increased by 25 %
Increased by 33.3 %
For double angles carrying tension, placed back to back and connected to either side of the gusset plate, the sectional area of the section, is equal to cross sectional area of
The section
The section plus area of rivet holes
The section minus area of rivet holes
The section multiplied by the area of the rivet hole
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
Design of a riveted joint is based on the assumption:
Bending stress in rivets is accounted for
Riveted hole is assumed to be completely filled by the rivet
Stress in the plate in not uniform
Friction between plates is taken into account
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
For steel members not exposed to weather, the thickness of steel should not be less than
4.5 mm
6 mm
8 mm
10 mm
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
The most economical section for a column, is
Rectangular
Solid round
Flat strip
Tubular section
The statical method of plastic analysis satisfies
Equilibrium and mechanism conditions
Equilibrium and plastic moment conditions
Mechanism and plastic moment conditions
Equilibrium condition only
The effective length of a double angle strut with angles placed back to back and connected to both the sides of a gusset plate, by not less than two rivets, is
0.5 L
0.67 L
0.85 L
2 L
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 mechanism method of plastic analysis satisfies
Equilibrium and mechanism conditions
Equilibrium and plastic moment conditions
Mechanism and plastic moment conditions
Equilibrium condition only
A column splice is used to increase
Length of the column
Strength of the column
Cross-sectional area of the column
None of these
Economical depth of a plate girder corresponds to
Minimum weight
Minimum depth
Maximum weight
Minimum thickness of web
For determination of allowable stress in axial compression, Indian Standard Institution has adopted
Euler's formula
Rankine formula
Perry Robertson formula
Secant formula
Effective length of a column effectively held in position at both ends and restrained in direction at one end, is
L
0.67 L
0.85 L
1.5 L
Minimum thickness of web in a plate girder, when the plate is accessible and also exposed to weather, is
5 mm
6 mm
8 mm
10 mm
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
The allowable stress in axial tension is generally kept less if thickness of the member is more than
10 mm
12 mm
15 mm
20 mm
Spans of continuous fillers are considered approximately equal if the longest span does not exceed the shortest span by more than
5 %
10 %
15 %
20 %
As per IS : 875, for the purposes of specifying basic wind velocity, the country has been divided into
4 zones
5 zones
6 zones
7 zones
The strength of a riveted lap joint is equal to its
Shearing strength
Bearing strength
Tearing strength
Least of (a), (b) and (c)
For a rectangular section, the ratio of the maximum and average shear stresses, is
1.5
2.0
2.5
3.5
According to I.S. : 800 - 1871, lacing bars resist transverse shear equal to
1.0% of the axial load
2.0% of the axial load
2.5% of the axial load
3.0% of the axial load
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
In moment resistant connections, the moment resistance of riveted connection depends upon
Shear in rivets
Compression in rivets
Tension in rivets
Strength of rivets in bearing
For a column of height L fixed in position and direction both at its top and bottom, its effective length, is
L
1/√2 × L
½ L
2L