Engineering Economy and Equipments MCQ Quiz - Objective Question with Answer for Engineering Economy and Equipments - Download Free PDF

Explanation:

The cycle time of an earth-moving machine refers to the time required to complete one full operation cycle: digging → loading → swinging → dumping → returning.

Dragline:

• Used for excavating below machine level (e.g., deep pits, underwater).

• Has a longer cycle time due to the swinging arc and cable operation.

• Not ideal for quick repetitive operations.

Dipper Shovel (Front Shovel):

• Used for excavating above machine level (e.g., benches in quarries).

• Has short and fast cycle time due to direct digging, short swing, and dumping cycle.

• Suitable for bulk excavation and fast loading operations.

 Additional InformationClamshell:

• Mainly used for vertical lifting like loading loose material or excavation from depths.

• Slow due to opening/closing of the bucket and vertical movement.

• Has one of the longest cycle times among lifting/excavation tools.

Hoe (Backhoe):

• Suitable for excavating below ground level.

• Moderate cycle time, as it has to move the arm, rotate, and dump material.

• Used where precision is more important than speed.

Explanation:

A Tunnel Boring Machine (TBM) is a specialized construction machine used primarily for mechanized excavation of tunnels through soil or rock. Its function is to excavate with precision, reduce ground disturbance, and provide continuous support during tunneling.

Key Features of TBM:

• Controlled Excavation: TBMs cut through ground with a rotating cutterhead, removing material safely and efficiently.

• Minimized Surface Disruption: Ideal for urban tunneling, where minimizing surface settlement is critical.

• Simultaneous Lining: Many TBMs install precast concrete segments to form the tunnel lining as they progress.

• Applications: Used in subways, water tunnels, sewer tunnels, rail tunnels, and hydropower projects.

 Additional InformationNew Austrian Tunnelling Method (NATM)

• NATM is based on the principle of utilizing the in-situ ground (rock or soil) as a structural component to support the tunnel.

• Instead of resisting ground pressure completely, the method allows some controlled deformation, which helps mobilize the strength of the surrounding ground mass.

• It emphasizes monitoring and adapting construction based on actual ground behavior.

• The tunnel is excavated in small sections, usually using conventional methods like drilling and blasting or mechanical excavation.

• After excavation, immediate temporary support such as shotcrete (sprayed concrete), rock bolts, and sometimes wire mesh is applied.

• Final lining (usually cast-in-place concrete) is added later, only after stability is confirmed.

Piston Pump

• A piston pump is a reciprocating positive displacement pump that moves material by pushing it with a piston inside a cylinder.

• It is ideal for dense, viscous, and solid-laden materials, making it the standard choice for pumping Ready Mix Concrete.

• It provides high pressure and can transport concrete over long distances and vertical heights with consistency and minimal segregation.

Additional Information

Centrifugal Pump

• A centrifugal pump uses a rotating impeller to impart velocity to a fluid and convert it into flow.

• It is best suited for clear or lightly contaminated liquids and is widely used in water supply, irrigation, and industrial processes.

• Not suitable for pumping RMC, as the abrasive and solid particles can clog or damage the impeller and reduce efficiency.

Gear Pump

• A gear pump is a positive displacement pump that moves fluid using meshing gears.

• It is used for low-viscosity fluids such as oils, lubricants, and chemicals in hydraulic systems.

• Gear pumps are not designed for handling abrasive or solid-laden materials like concrete.

Submersible Pump

• A submersible pump is designed to operate while fully submerged in the fluid it is pumping.

• Commonly used for dewatering, sewage pumping, and groundwater extraction, not for thick materials like concrete.

• It is not suitable for conveying Ready Mix Concrete (RMC) due to the high viscosity and presence of coarse aggregates.

Tower Crane Truck

• A tower crane is a lifting equipment, not a dump truck. It is used to hoist and move heavy materials vertically and horizontally on construction sites, especially for tall buildings.

• Tower cranes are typically fixed in place or assembled on-site. A tower crane truck may refer to a transport vehicle for crane components, but it is not involved in dumping operations.

• This equipment is designed for precision lifting rather than material hauling or unloading.

Additional Information

• A bottom dump truck has a clamshell-type gate at the bottom of the trailer body. It discharges material downward in a controlled and uniform flow, ideal for road construction and layering aggregate.

• It provides efficient unloading without the need to raise the bed, reducing the risk of overturning.

• Typically used for hauling loose materials like gravel, sand, or coal where linear spreading is needed.

Articulated Dump Truck

• An articulated dump truck has two sections (cab and trailer) connected by a hinge or articulation joint, allowing for better maneuverability on uneven terrain.

• The front section steers the truck, while the rear holds the load. It’s commonly used in mining, earthmoving, and off-road construction projects.

• This design allows it to operate in tight and rough areas where rigid dump trucks may not perform efficiently.

Side or Rear Dump Truck

• These trucks use hydraulic rams to tip the truck bed to the rear or side, unloading the contents quickly.

• Rear dump trucks are common in general construction, while side dump trucks are preferred where space or traffic restricts rear unloading.

• They are used for bulk material transport, such as demolition waste, soil, and construction aggregate.

Explanation:

A Grader (also called a motor grader) is a specialized machine used primarily for grading and leveling large areas of land, especially in road construction and site preparation.

Key Features of a Grader:

• Equipped with a long adjustable blade between the front and rear wheels, it can fine-grade surfaces with high precision.

• Essential in forming the final subgrade layer before asphalt or concrete is laid.

• Maintains proper slope and camber.

• Operator can tilt, raise, or rotate the blade for contouring, ditching, and grading as per design.

• Ideal for finishing operations, where uniform surface and compaction are required after bulk earthwork.

 Additional Information

Bulldozer:

• Best for pushing large quantities of soil or debris, not precise grading.

• Used in rough grading or clearing vegetation.

Excavator:

• Designed for digging and trenching, not surface leveling.

• Works well in confined areas or for vertical cuts.

Scraper:

• Used to cut, collect, and transport earth over moderate distances.

• It can do rough leveling but lacks the fine precision of a grader.

Concept: 

Sinking fund:

(i) It is a fund that is built up for the sole purpose of replacement or reconstruction of the property when it loses its utility at the end of its useful life. The fund is regularly deposited in a bank or with an insurance agency so that on the expiry of the period utility of the building, a sufficient amount is available for its replacement. It is given as,

\(\text{Annual installment of sinking fund}, S_c = \frac{SR}{(1 \;+ \;R)^n - 1}​​\)

Where,

S = Total amount of Sinking fund accumulated at the end of utility period = Purchase cost - Scrap value

R = rate of interest and n = utility period

Calculation:

Given: R = 10%, n = 2 years, S = 10000

\(\text{Annual installment of sinking fund}, S_c = \frac{10000 ~\times~ 0.1}{(1\; +\;0.1)^2- 1}\)

\(\text{Annual installment of sinking fund}, S_c = \frac{1000}{0.21}\)

⇒ S_c = 1000/0.21

Explanation:

Classification of Construction Equipment(according to work cycle):

1. Intermittent Type:

• Bulldozers
• Scrappers
• Power Shovels
• Concrete Mixers
• Dragline

2. Continuous Flow Type:

• Air Compressors
• Belt Conveyors

3. Mixed Type:

• Motor Graders

Explanation:

BackHoe:

• A backhoe is an excavating tool that consists of a metal plate attached to a long handle with an acute angle.
• The plate having a sharp edge is used to excavate the soil. For small work of excavation, it is a widely preferred tool.

Dragline:

• Since the basic character of the machine is dragging the bucket against the material to be dug, it is called as DRAGLINE.

Side discharge loader:

• It is a track-mounted electro-hydraulically operated side discharging bucket loader with a smooth control system and excellent maneuverability. It is a low-profile high-output machine.

Dozer:

• The meaning of dozer is a tractor-driven machine usually having a broad horizontal blade for moving earth

Confusion Points The difference between a dozer and a backhoe, is that in the dozer the blade is horizontal, while in backhoe, the blade is vertical

Explanation:

Hoisting:

• Hoisting is lifting a weight from one location and moving it to another location that is at a reasonable distance.

The various hoisting equipment are:

1. Pulley and sheave block
2. Chain hoists
3. Mobile cranes
4. Winch
5. Jack
6. Shear leg
7. Tower cranes
8. Whirler cranes
9. Derrick cranes
10. Gantry cranes

Important Points

•  A dragline is an excavating machine in which the bucket is attached by cables and operates by being drawn toward the machine.
• Hoe is handheld equipment with a light blade and used to till the soil and eradicate weeds.
• A Clamshell is a bucket with two hinged jaws carried by a crane in which excavated earth is stored. 

Concept:

Sinking fund:

(i) It is a fund that is built up for the sole purpose of replacement or reconstruction of the property when it loses its utility at the end of its useful life. The fund is regularly deposited in a bank or with an insurance agency so that on the expiry of the period utility of the building, a sufficient amount is available for its replacement. It is given as,

\(\text{Annual installment of sinking fund}, S_c = \frac{SR}{(1 + R)^n - 1}\)

Where,

S = Total amount of Sinking fund accumulated at the end of utility period = Purchase cost - Scrap value

R = rate of interest and n = utility period

Calculation:

Given,

Purchase cost = Rs. 30000, R = 4%,

n = 20 years, Scrap value = 10% of purchase cost,

∵ We know that, S = Purchase cost - Scrap value

⇒ S = 30000 - 0.1 × 30000

∴ S = Rs. 27000

∵ We know that, \(\text{Annual installment of sinking fund}, S_c = \frac{SR}{(1 + R)^n - 1}\) 

⇒ \( S_c = \frac{27000\times 0.04}{(1 + 0.04)^{20} - 1}\)

∴ S_c = Rs. 906.70

Explanation:

Cranes: 

• A crane is a significant type of construction machine that’s utilized to move the loads horizontally. Equipped with a hoist rope, cable ropes and sheaves, it may be used to lift heavy loads or transport them to other places.
• The mechanical benefits created by several elements on the crane may produce powerful strength.

Explanation:

Market Rate:

• The market rate is defined as the usual price charged for goods and services in the free market. Or in other words, if any product (commodity) buy and sold at any price in the open market (public market) is called the market rate of goods (commodity).

Item Rate:

• Item rate is defined as the price of a particular commodity or service.

Storage Rate:

• Storage rate is defined as the price of a commodity that can be bought in huge quantities at less than the market rate and stored. Or in other words Storage rate is defined as the price of a commodity that can be bought and stored in large quantities at a lower than the market rate.

Current Rate:

• The current rate is defined as the last recent price of goods or services that have been bought or sold.

Explanation:

Return on investment (ROI)

• Return on investment analysis compares the economic value of the benefits of programs and policies with their associated costs. Also referred to as  benefit-cost analysis, this approach to measuring value can be used to assess a range of education, human service, and health programs     
• It is a performance measure used to evaluate the efficiency or profitability of an investment or compare the efficiency of a number of different investments.
• ROI tries to directly measure the amount of return on a particular investment, relative to the investment’s cost.
• To calculate ROI, the benefit (or return) of an investment is divided by the cost of the investment. The result is expressed as a percentage or a ratio.

Key Benefits:

• Return on Investment (ROI) is a popular profitability metric used to evaluate how well an investment has performed.
• ROI is expressed as a percentage and is calculated by dividing an investment's net profit (or loss) by its initial cost or outlay.
• ROI can be used to make apples-to-apples comparisons and rank investments in different projects or assets.
• ROI does not take into account the holding period or passage of time, and so it can miss opportunity costs of investing elsewhere.
• Whether or not something delivers a good ROI should be compared relative to other available opportunities.

Explanation:

Rationalisation:

• Rationalization is the process of converting a pre-existing workflow to a workflow that is more goal-oriented and based on a specific set of rules.
• Asset rationalization is the process of reorganizing a company's assets in order to improve and boost operating efficiency.

Depreciation:

• Depreciation is a reduction in the value of the asset with the passage of time.
• Generally, the decline in the value of the asset is due to wear and tear deterioration or obsolescence.

Indexation:

• Indexation is the process or technique through which the Government or Organization adjusts the purchase price of an asset to account for inflation between the time you bought and sold it. In simple words, indexation allows you to increase the purchase price depending on the inflation rate in the economy.
• Indexation can be done to adjust for the effects of inflation, cost of living, or input prices over time, or for different prices and costs in different geographic regions.
• Indexation is often used to raise wages in inflationary environments, where failure to negotiate regular wage increases will result in real wage cuts for workers.

Escalation:

• Escalation refers to a persistent (or sustained) rise in the price of specific commodities, goods, or services due to a combination of inflation, supply and demand, and other effects such as environmental, geological, and engineering changes.

Hence, the measure and adjustment of price levels for goods and services across a broad sector of the economy are called indexation.

Explanation:

Crane:

A crane is a type of machine which consists of hoist rope, wire rope, and sheaves that can be used for both lifting and lowering the materials.

Different types of cranes:

• Hammerhead  cranes
• Self-erecting lifting cranes
• Bridge cranes
• Gantry cranes
• Monorail crane
• Jib crane
• Work station cranes.
• Whirler crane
• Derrick cranes

So, ​Johnson is not any type of crane.