According to Whitney's theory, depth of stress block for a balanced section of a concrete beam is limited to
0.43 d
0.537 d
0.68 d
0.85 d Where d is effective depth of beam
Correct Answer :
B. 0.537 d
Related Questions
For road pavements, the cement generally used, is
Ordinary Portland cement
Rapid hardening cement
Low heat cement
Blast furnace slag cement
Ultimate strength of cold drawn high steel wires
Increases with increase in diameter of bar
Decreases with increase in diameter of bar
Does not depend on diameter of bar
None of the above
Addition of pozzolana to cement
Decreases workability
Increases strength
Increases heat of hydration
None of these
The most commonly used admixture which prolongs the setting and hardening time is
Gypsum
Calcium chloride
Sodium silicate
All of the above
The process of mixing, transporting, placing and compacting concrete using Ordinary Port land Cement should not take more than
30 minutes
40 minutes
60 minutes
90 minutes
The grade of concrete not recommended by I.S. : 456, is
M 100
M 200
M 300
M 500
Assertion A : The load factor for live load is greater than that for dead load. Reason R : The live loads are more uncertain than dead loads. Select your answer based on the coding system given below:
Both A and R is true and R is the correct explanation of A
Both A and R is true but R is not the correct explanation of A
A is true but R is false
A is false but R is true
For quality control of Portland cement, the test essentially done is
Setting time
Tensile strength
Consistency
All the above
The effect of creep on modular ratio is
To decrease it
To increase it
Either to decrease or to increase it
To keep it unchanged
For ensuring quality of concrete, use
Single sized aggregates
Two sized aggregate
Graded aggregates
Coarse aggregates
To ensure constant moisture content in aggregates
Area of each aggregate pile should be large
Height of each aggregate pile should not exceed 1.50 m
Aggregate pile should be left for 24 hours before aggregates are used
All the above
The centroid of compressive force, from the extreme compression fiber, in limit state design lies at a distance of (Where xu is the depth of neutral axis at the limit state of collapse)
0.367 xu
0.416 xu
0.446 xu
0.573 xu
The shrinkage of concrete
Is proportional to water content is the mix
Is proportional to cement concrete
Increases with age of concrete
All the above
In counterfort type retaining walls (i) The vertical slab is designed as a continuous slab (ii) The heel slab is designed as a continuous slab (iii) The vertical slab is designed as a cantilever (iv) The heel slab is designed as a cantilever The correct answer is
(i) and (ii)
(i)and(iv)
(ii) and (iii)
(iii) and (iv)
'Ware house pack' of cement means
Full capacity of the ware house
Pressure exertion of the bags of upper layers
Pressure compaction of the bags on lower layers
Packing the ware house
The aggregate impact value of the aggregate used in
Building concrete is less than 45
Road pavement concrete is less than 30
Runway concrete is less than 30
All the above
A continuous beam is deemed to be a deep beam when the ratio of effective span to overall depth (1/D) is less than
1.5
2.0
2.5
3.0
Pick up the incorrect statement from the following:
The degree of grinding of cement, is called fineness
The process of changing cement paste into hard mass, is known as setting of cement
The phenomenon by virtue of which cement does not allow transmission of sound, is known as soundness of cement
The heat generated during chemical reaction of cement with water, is known as heat of hydration
For the construction of the retaining structures, the type of concrete mix to be used, is
1 : 3 : 6
1 : 2 : 4
1 : 1 ½ : 3
1 : 4 : 8
Ordinary Portland cement is manufactured from
Lime stone and clay
Gypsum and lime
Pozzolana
Lime, pozzolana and clay
For the construction of cement concrete dams, the maximum permissible size of the aggregates, is
40 mm
50 mm
60 mm
70 mm
The datum temperature for maturity by Plowman, is
23°C
0°
- 5.6°C
- 11.7°C
Workability improved by adding
Fly ash
Hydrated lime
Calcium chloride
All the above
The increased cohesiveness of concrete, makes it
Less liable to segregation
More liable to segregation
More liable to bleeding
More liable for surface scaling in frosty weather
Minimum pitch of transverse reinforcement in a column is
The least lateral dimension of the member
Sixteen times the smallest diameter of longitudinal reinforcement bar to be tied
Forty-eight times the diameter of transverse reinforcement
Lesser of the above three values
Due to shrinkage stresses, a simply supported beam having reinforcement only at bottom tends to
Deflect downward
Deflect upward
Deflect downward or upward
None of the above
Pick up the incorrect statement from the following:
In properly graded aggregates, bulk density is more
In single size aggregates, bulk density is least
In single size aggregates, bulk density is maximum
None of these
Critical section for shear in case of flat slabs is at a distance of
Effective depth of slab from periphery of column/drop panel
d/2 from periphery of column/capital/ drop panel
At the drop panel of slab
At the periphery of column
Pick up the correct statement from the following:
Continuous grading is not necessary for obtaining a minimum of air voids
The omission of a certain size of aggregate is shown by a straight horizontal line on the grading curve
The omission of a certain size of aggregate in concrete increases the workability but also increases the liability to segregation
All the above
For the design of retaining walls, the minimum factor of safety against overturning is taken as
1.5
2.0
2.5
3.0