What is the main function of reinforcement in concrete?
A Resist compression
B Resist tension
C Resist tension
D Increase density
Reinforcement, typically steel bars or mesh, is used in concrete to resist tensile stresses. Concrete is strong in compression but weak in tension, and reinforcement enhances its ability to resist tensile forces.
What type of slab 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. This slab is ideal for simple structures with longer spans, where the load distribution is concentrated in one direction.
What is the purpose of structural retrofitting?
A Strengthen existing structures
B Increase foundation depth
C Reduce material costs
D Increase load-carrying capacity
Structural retrofitting involves modifying or strengthening existing structures to improve their load-bearing capacity, seismic resistance, or durability. This is done to accommodate higher loads or improve safety, particularly in aging buildings.
What is the primary use of a pile foundation?
A Increase load-bearing capacity
B Improve soil quality
C Distribute loads evenly
D Prevent soil settlement
Pile foundations are used to transfer the load of a structure to deeper, more stable layers of soil or rock. They are particularly useful in areas with weak surface soils, preventing excessive settlement.
Which concrete grade is commonly used for high-strength applications?
A M20
B M40
C M30
D M50
M40 concrete is used for high-strength applications, such as bridges, high-rise buildings, and heavy-duty pavements. It provides superior durability and can withstand high compressive loads in demanding conditions.
What does ductile detailing ensure in seismic design?
A Increase stiffness
B Prevent cracking
C Energy dissipation
D Increase bending strength
Ductile detailing allows structures to undergo large deformations without failure during an earthquake. This enables the structure to absorb and dissipate seismic energy, preventing catastrophic failure during seismic events.
What is the role of shear reinforcement in concrete beams?
A Increase strength
B Prevent deflection
C Prevent cracking
D Resist shear stresses
Shear reinforcement, such as stirrups or bent-up bars, helps resist diagonal tensile stresses caused by shear forces. This prevents shear failure and diagonal cracking, particularly in regions near supports or concentrated loads.
What is the most commonly used concrete grade for slabs?
A M20
B M30
C M40
D M10
M20 concrete is commonly used for slabs because it offers a good balance of strength, workability, and cost-effectiveness. It is suitable for most residential and light commercial building applications, providing adequate performance.
What type of foundation is suitable for high-rise buildings?
A Raft foundation
B Pile foundation
C Slab foundation
D Isolated foundation
Pile foundations are ideal for high-rise buildings as they transfer the structure’s loads to deeper, stable layers of soil or rock. This prevents settlement and provides the stability needed for large structures.
What is the primary function of a pile cap?
A Improve foundation depth
B Increase load capacity
C Distribute loads to piles
D Protect piles from corrosion
A pile cap is a thick concrete slab that distributes the load from the superstructure evenly across multiple piles, ensuring that the load is transferred uniformly to the deep foundation system.
What is the main purpose of reinforcement detailing in columns?
A Prevent shear failure
B Improve durability
C Increase bending strength
D Ensure proper anchorage
Reinforcement detailing in columns ensures the proper placement, size, and anchorage of reinforcement bars. This ensures the column can effectively resist axial loads and bending moments, preventing failure during extreme loading conditions.
What is the typical span-to-depth ratio of a deep beam?
A 3:1
B Less than 2
C 4:1
D 2:1
Deep beams have a span-to-depth ratio of less than 2. They are designed to resist significant shear stresses and bending moments. These beams require special reinforcement and are often used in taller structures.
What is the effect of low permeability in concrete?
A Increase durability
B Decrease workability
C Reduce strength
D Increase shrinkage
Low permeability in concrete enhances its durability by reducing the ingress of harmful substances like water, chemicals, and gases. This makes concrete more resistant to environmental conditions such as freeze-thaw cycles and chemical attacks.
What does bond in reinforced concrete ensure?
A Load distribution
B Durability
C Strength transfer
D Crack prevention
The bond between concrete and reinforcement ensures that stresses are effectively transferred from the concrete to the steel reinforcement. This bond allows the two materials to work together as a composite unit to resist applied loads.
What type of slab is commonly used in multi-story buildings?
A One-way slab
B Two-way slab
C Flat slab
D Cantilever slab
Two-way slabs are commonly used in multi-story buildings because they are supported on all four sides and distribute loads in both directions. This helps improve structural efficiency and load-bearing capacity in buildings with regular floor plans.