What is the main purpose of shear reinforcement in concrete?
A Increase bending strength
B Increase stiffness
C Resist shear forces
D Improve durability
Shear reinforcement, such as stirrups, prevents diagonal cracking caused by shear forces in concrete beams. Concrete alone is weak under shear stress, and reinforcement ensures structural stability and prevents premature failure.
What is the role of longitudinal reinforcement in columns?
A Resist compression
B Resist tension
C Resist shear
D Resist bending
Longitudinal reinforcement in columns primarily resists compression, which is the main stress experienced by vertical elements like columns. These bars provide the necessary strength to carry axial loads and bending moments.
Which of the following concrete grades is used for high-strength applications?
A M25
B M40
C M30
D M15
M40 concrete grade is used for high-strength applications such as bridges and high-rise buildings. It has a compressive strength of 40 MPa and provides excellent durability under heavy loads and adverse conditions.
What does the term “creep” in concrete refer to?
A Cracking under stress
B Shrinkage during curing
C Moisture loss
D Deformation under load
Creep is the gradual deformation of concrete under sustained loads over time. It results in long-term deflection and stress redistribution, especially in beams or slabs subjected to constant loading.
What is the purpose of concrete mix design?
A Aesthetic design
B Reinforcement calculation
C Strength and durability
D Cost estimation
Concrete mix design ensures the correct proportions of materials (cement, water, aggregates) to achieve the desired strength, workability, and durability. Proper mix design ensures the structure performs well over its lifespan.
What is the effect of low permeability in concrete?
A Increases durability
B Increases cost
C Reduces durability
D Increases shrinkage
Low permeability in concrete reduces the ingress of harmful substances like water, chemicals, and gases, which increases the durability of the material. This prevents corrosion and degradation of concrete over time.
Which slab type transfers loads in one direction?
A Cantilever slab
B One-way slab
C Two-way slab
D Flat slab
A one-way slab is supported on two opposite sides and transfers loads in one direction. These slabs are commonly used in buildings where the length-to-width ratio is large, making them ideal for simple structures.
What is a primary function of a pile cap?
A Increase load capacity
B Improve foundation depth
C Transfer load to piles
D Increase stability
Pile caps are thick concrete mats placed over groups of piles. Their primary function is to distribute loads from the superstructure to the piles, ensuring uniform load transfer and stability for the foundation.
What is the purpose of bond between concrete and reinforcement?
A Prevent corrosion
B Increase weight
C Improve durability
D Transfer stresses
The bond between concrete and reinforcement allows the two materials to act together as a composite unit. This bond ensures that stresses are transferred from the concrete to the reinforcement, allowing efficient load distribution.
Which concrete grade is used for pavements?
A M20
B M10
C M30
D M25
M20 grade concrete is commonly used for pavement construction due to its adequate strength and workability. It provides good performance under moderate traffic loads and environmental conditions.
What type of slab has its load distributed in both directions?
A Cantilever slab
B Two-way slab
C Flat slab
D One-way slab
A two-way slab is supported on all four sides and transfers loads in both directions. It is used when the span-to-width ratio is less than or equal to 2, ensuring efficient load distribution.
What is the primary advantage of ductile detailing in earthquake design?
A Prevent deflection
B Increase stiffness
C Reduce weight
D Improve energy absorption
Ductile detailing ensures that structures can deform significantly without collapsing during seismic events. This helps structures absorb and dissipate earthquake energy, reducing the likelihood of catastrophic failure.
What is the minimum percentage of reinforcement in slabs?
A 0.5%
B 1%
C 1.5%
D 2%
The minimum reinforcement in slabs is typically 0.5% of the cross-sectional area. This ensures adequate tensile strength and prevents cracking under normal load conditions, providing structural stability.
Which of the following types of foundation is most commonly used for high-rise buildings?
A Slab foundation
B Isolated foundation
C Pile foundation
D Raft foundation
Pile foundations are commonly used for high-rise buildings to transfer loads to deep, stable soil or rock layers. They prevent excessive settlement and provide stability in areas with weak surface soil.
What is the primary purpose of reinforcement detailing?
A Durability improvement
B Placement and spacing
C Strength calculation
D Aesthetic design
Reinforcement detailing involves specifying the proper placement, size, and spacing of reinforcement bars in concrete elements. This ensures effective load transfer, structural integrity, and compliance with design requirements.