What does serviceability in reinforced concrete design ensure?
A Structural stability
B Usability and comfort
C Safe loads
D Material durability
Serviceability ensures that structures perform well under normal conditions without excessive deflection, cracking, or vibrations, maintaining comfort and usability while not compromising structural safety or integrity.
What is the purpose of using stirrups in beams?
A Prevent shear failure
B Resist bending
C Increase durability
D Prevent deflection
Stirrups are used as shear reinforcement in beams to resist diagonal shear stresses. They help prevent shear failure by confining the concrete and transferring the stresses between the reinforcement and the concrete.
What is the primary cause of deflection in concrete beams?
A Overloading
B Insufficient reinforcement
C High water-cement ratio
D Low temperature
Excessive deflection in concrete beams is typically caused by insufficient reinforcement. This weakens the beam’s ability to resist bending stresses, leading to larger-than-acceptable deflections under normal load conditions.
What type of foundation is best for deep, weak soils?
A Isolated foundation
B Pile foundation
C Raft foundation
D Slab foundation
Pile foundations are ideal for deep, weak soils because they transfer loads to deeper, more stable soil or rock layers. They help prevent settlement by providing additional stability and support.
What is the purpose of ductile detailing in reinforced concrete design?
A Improve energy absorption
B Prevent cracking
C Increase strength
D Decrease construction cost
Ductile detailing allows structures to undergo large deformations during seismic events without sudden failure. This enhances the structure’s ability to absorb and dissipate seismic energy, reducing the risk of collapse.
What is the effect of high water-cement ratio in concrete?
A Increases strength
B Reduces durability
C Increases shrinkage
D Reduces workability
A high water-cement ratio increases the porosity of the concrete, which reduces its durability. This makes the concrete more vulnerable to environmental attacks, such as water infiltration and chemical corrosion.
What is the function of a pile cap?
A Distribute load
B Reduce soil pressure
C Improve drainage
D Increase pile strength
Pile caps distribute the load from the superstructure to the underlying piles. They ensure that the load is evenly transferred to each pile, providing stability and preventing settlement of the foundation system.
What does punching shear failure occur due to?
A Low compression
B Concentrated load near column
C Excessive bending
D High deflection
Punching shear occurs when a concentrated load, such as from a column, creates high shear stresses in flat slabs. If the slab is not designed correctly, these stresses lead to sudden failure around the column.
What type of concrete is commonly used in high-rise building foundations?
A M25
B M15
C M40
D M20
M40 concrete is commonly used in high-rise building foundations due to its high compressive strength and durability. It is ideal for heavy-load applications like large commercial or residential buildings and bridges.
What is the role of reinforcement detailing in reinforced concrete design?
A Prevent cracking
B Ensure proper placement
C Reduce material cost
D Improve workability
Reinforcement detailing involves specifying the correct size, location, and spacing of reinforcement bars in concrete elements. Proper detailing ensures that the structure can effectively carry the loads and perform well under stress.
What is a typical use for a flat slab?
A Large span areas
B Foundations
C Residential buildings
D Driveways
Flat slabs are commonly used in large span areas such as commercial buildings or multi-story parking structures. They eliminate beams, simplifying construction, and providing flexibility in layout and design.
What is the purpose of concrete mix design?
A Reduce cost
B Reduce weight
C Achieve desired strength
D Improve workability
Concrete mix design ensures the correct proportions of cement, aggregates, and water to achieve the desired strength and durability for a specific application. It balances workability, cost, and performance for structural needs.
What is the primary reason for using reinforcement in concrete columns?
A Increase durability
B Resist compression
C Resist shear
D Resist bending
Reinforcement in concrete columns is primarily used to resist axial compressive loads. Concrete can withstand compressive forces, but the reinforcement provides additional strength and prevents column failure under heavy loads.
What does “punching shear” in flat slabs result from?
A Shrinkage
B Excessive deflection
C Overloading
D Concentrated column load
Punching shear occurs in flat slabs due to concentrated loads from columns. These loads create high shear stresses around the column’s perimeter, which can lead to localized failure if not properly reinforced.
What is the main function of a retaining wall in reinforced concrete?
A Resist lateral soil pressure
B Prevent water seepage
C Provide aesthetic value
D Prevent cracking
Retaining walls are used to resist the lateral soil pressure and prevent soil movement. They are commonly used to support slopes, prevent erosion, and create level surfaces for building foundations in hilly or uneven terrain.