1. Which type of foundation is typically used for bridges built on stable soil conditions?
a) Shallow foundations
b) Deep foundations
c) Pneumatic caissons
d) River training works
Answer: a) Shallow foundations
Explanation: Shallow foundations are commonly used for bridges constructed on stable soil conditions where the load-bearing capacity of the soil near the surface is sufficient to support the structure without the need for extensive excavation or deep foundation systems.
2. What is the primary function of bridge bearings?
a) To support the bridge deck
b) To resist lateral loads
c) To provide flexibility and movement
d) To anchor the bridge to the ground
Answer: c) To provide flexibility and movement
Explanation: Bridge bearings are designed to accommodate movements and rotations caused by factors such as thermal expansion, traffic loads, and seismic activity, thereby preventing structural damage and ensuring the longevity of the bridge.
3. Which type of foundation is suitable for bridges spanning deep water bodies or soft soils?
a) Piles
b) Shallow foundations
c) Elastomeric bearings
d) Expansion joints
Answer: a) Piles
Explanation: Piles are deep foundation elements driven into the ground to transfer structural loads to deeper, more stable soil or rock layers. They are commonly used for bridges spanning deep water bodies or soft soils where shallow foundations may not be feasible.
4. Why are expansion joints necessary in bridge construction?
a) To prevent the bridge from collapsing
b) To allow for expansion and contraction due to temperature changes
c) To minimize vibrations from passing vehicles
d) To increase the load-bearing capacity of the bridge
Answer: b) To allow for expansion and contraction due to temperature changes
Explanation: Expansion joints are crucial components of bridge structures as they accommodate thermal expansion and contraction of bridge materials due to temperature variations, thereby preventing cracking, distortion, or structural damage.
5. What is the primary purpose of river training works in bridge construction?
a) To reinforce the bridge foundation
b) To prevent erosion of river banks
c) To divert river flow away from the bridge
d) To increase the width of the river
Answer: b) To prevent erosion of river banks
Explanation: River training works involve techniques such as bank protection, revetments, and channel stabilization to prevent erosion of river banks, which helps maintain the stability and integrity of bridge foundations and adjacent structures.
6. Which type of foundation involves sinking a watertight chamber into the riverbed and then removing the water to create a dry working environment?
a) Pneumatic caissons
b) Elastomeric bearings
c) Piles
d) Shallow foundations
Answer: a) Pneumatic caissons
Explanation: Pneumatic caissons are used in bridge construction to create foundations in areas with shallow water or soft soil conditions. They involve sinking a watertight chamber into the riverbed, which is then pressurized to expel water, creating a dry working environment for construction.
7. What is the primary function of elastomeric bearings in bridge construction?
a) To resist lateral loads
b) To provide flexibility and movement
c) To support the bridge deck
d) To increase the load-bearing capacity of the bridge
Answer: b) To provide flexibility and movement
Explanation: Elastomeric bearings are designed to accommodate movements and rotations of bridge superstructures caused by factors such as thermal expansion, traffic loads, and seismic activity. They provide flexibility while supporting the bridge deck, thereby reducing stress and preventing structural damage.
8. Which type of expansion joint is commonly used to accommodate large horizontal movements in bridge structures?
a) Sliding expansion joints
b) Modular expansion joints
c) Finger expansion joints
d) Compression seals
Answer: b) Modular expansion joints
Explanation: Modular expansion joints are designed to accommodate large horizontal movements in bridge structures by utilizing individual modules that can slide or rotate relative to each other. They are commonly used in long-span bridges or structures subjected to significant thermal or seismic loads.
9. Which type of foundation transfers structural loads through columns or shafts embedded into the ground?
a) Piles
b) Shallow foundations
c) River training works
d) Deep foundations
Answer: d) Deep foundations
Explanation: Deep foundations, such as piles, transfer structural loads from bridges to deeper, more stable soil or rock layers through columns or shafts embedded into the ground. They are used when shallow foundations are inadequate due to weak soil conditions or the presence of water.
10. When are expansion joints necessary for bridge construction?
a) Only in areas prone to earthquakes
b) Only in areas with extreme temperature fluctuations
c) Whenever there is a change in direction, elevation, or alignment of the bridge
d) Only for bridges longer than 1 kilometer
Answer: c) Whenever there is a change in direction, elevation, or alignment of the bridge
Explanation: Expansion joints are necessary for bridge construction whenever there is a change in direction, elevation, or alignment of the bridge to accommodate movements caused by factors such as temperature changes, traffic loads, and seismic activity, ensuring structural integrity and longevity.