What is the primary purpose of providing lap length in reinforcement?
A Improve aesthetics
B Increase concrete strength
C Reduce cost
D Ensure continuity of bars
Lap length is the overlapping length of reinforcement bars provided to ensure continuity and proper transfer of stresses between adjacent bars. It maintains structural integrity and prevents weak joints in reinforced concrete elements.
Which of the following is a characteristic of high–strength concrete?
A High shrinkage
B Low compressive strength
C Compressive strength > 60 MPa
D High water–cement ratio
High–strength concrete has a compressive strength greater than 60 MPa. It is used in specialized structures like high–rise buildings and bridges, offering better durability and load–carrying capacity compared to normal–strength concrete.
What is the primary purpose of a beam–column joint in a structure?
A Improve aesthetics
B Transfer loads between beams and columns
C Increase bond strength
D Reduce deflection
Beam–column joints are critical in transferring loads between beams and columns. Proper design and detailing of these joints ensure structural stability, especially in earthquake–resistant structures.
Which of the following is a common cause of creep in concrete?
A Long–term loading
B High temperature
C Chemical reactions
D Rapid drying
Creep in concrete is the gradual deformation under sustained long–term loading. It occurs due to the slow movement of water within the concrete matrix and the rearrangement of its internal structure over time.
What is the primary purpose of a water tank in reinforced concrete design?
A Improve aesthetics
B Increase soil strength
C Store water
D Reduce foundation depth
Reinforced concrete water tanks are designed to store water for domestic, industrial, or firefighting purposes. They must be leak–proof, durable, and capable of withstanding hydrostatic pressure.
Which of the following is a key consideration in earthquake–resistant design?
A High stiffness
B High shrinkage
C Low reinforcement ratio
D Ductility
Ductility is crucial in earthquake–resistant design as it allows structures to undergo large deformations without sudden failure. This helps dissipate seismic energy and prevents collapse during earthquakes.
What is the primary purpose of the working stress method?
A Increase ductility
B Limit stresses under service loads
C Reduce deflection
D Ensure ultimate strength
The working stress method ensures that stresses in concrete and reinforcement remain within permissible limits under service loads. It focuses on elastic behavior and prevents excessive cracking or deflection.
Which of the following is a common type of foundation for high–rise buildings?
A Raft foundation
B Strip foundation
C Pile foundation
D Isolated foundation
Pile foundations are commonly used for high–rise buildings to transfer heavy loads to deep, stable soil strata or rock. They provide stability and prevent excessive settlement.
What is the primary purpose of reinforcement detailing?
A Reduce concrete strength
B Ensure proper placement of bars
C Increase shrinkage
D Improve aesthetics
Reinforcement detailing involves specifying the size, spacing, and arrangement of reinforcement bars. It ensures proper load transfer, structural integrity, and compliance with design requirements.
Which of the following is a common cause of deflection in beams?
A High compressive strength
B High bond strength
C Low water–cement ratio
D Low reinforcement ratio
Excessive deflection in beams is often caused by insufficient reinforcement or a low reinforcement ratio. It can also result from overloading, improper design, or inadequate stiffness.
What is the primary purpose of a flat slab in reinforced concrete design?
A Increase deflection
B Improve aesthetics
C Reduce construction time
D Reduce bond strength
Flat slabs are used to reduce construction time and costs by eliminating beams. They provide a flat ceiling surface, allowing flexible partitioning and easier installation of services.
Which of the following is a common cause of cracking in concrete?
A Shrinkage
B Low water–cement ratio
C High bond strength
D High compressive strength
Cracking in concrete is often caused by shrinkage, which occurs due to the loss of moisture during curing. Other causes include thermal stresses, overloading, and inadequate reinforcement.
What is the primary function of a pile cap?
A Increase concrete strength
B Transfer loads to piles
C Improve soil strength
D Reduce foundation depth
A pile cap is a thick concrete mat that distributes the load from a column or wall to a group of piles. It ensures uniform load transfer and provides stability to the foundation system.
Which of the following is a key factor in the durability of concrete?
A High bond strength
B High shrinkage
C Low permeability
D Low compressive strength
Durability of concrete depends on its ability to resist the ingress of harmful substances like water, chemicals, and gases. Low permeability, achieved through proper mix design and curing, enhances durability.
What is the primary purpose of torsion reinforcement in beams?
A Resist twisting forces
B Reduce deflection
C Improve bond strength
D Resist bending moments
Torsion reinforcement, such as closed stirrups and longitudinal bars, is provided in beams to resist twisting forces caused by eccentric loads or uneven support conditions, preventing structural failure.