Construction Operations and Methods
Construction Safety
Learning Objectives:
- Understand the significance of construction safety in the civil engineering field.
- Recognize the role of safety practices in preventing accidents, injuries, and fatalities on construction sites.
- Inadequate construction planning & scheduling
- Lack of proper training
- Deficient enforcement of training
- Unsafe equipment
- Unsafe methods or sequencing
- Unsafe site conditions
- Not using safety equipment that was provided
- Poor communication
- Lack of ineffective supervision
- Absence of safety rules and safe work procedure
- Lack of enforcement of safety rules and safe work procedure.
- Defective machinery on site
- Falling structure or loads, defective scaffolding, forklifts etc.
Personal Protective Equipment (PPE):
- Eye and face protection: Safety Glasses, Chemical Splash Goggles, Face Shields
- Hand protection: Light latex, vinyl or nitrile gloves, Insulated gloves, Wire mesh gloves
- Body protection: Traditional, Flame resistant, Barrier
- Respiratory protection: Surgical masks, N-95 respirators, Full-face respirators
- Hearing protection: Earplugs, Hearing band
Fall Protection:
- Safety Nets: Safety nets are crucial fall protection systems used in construction safety to prevent workers from falling from heights. They are installed horizontally under work areas, providing a cushioning surface to catch workers in the event of a fall. Safety nets help reduce the risk of serious injuries and fatalities on construction sites.
- Lanyards: Lanyards are essential components of fall arrest systems in construction safety. They are flexible lines or straps attached to a body harness worn by workers at height. In the event of a fall, lanyards deploy energy-absorbing mechanisms to reduce impact forces and prevent injury.
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Solved Example: 9378-01
In case of cantilever beam, reinforcement must be placed at the ________ of the member.
A. Top
B. Bottom
C. Sides
D. None of the above
Correct Answer: A
Solved Example: 9378-02
In sheds for ceiling works, __________ scaffolding is economical.
A. Suspended
B. Needle
C. Ordinary
D. None of the above
Correct Answer: A
Solved Example: 9378-03
Loss time injury incidence rate = ________
A. (Average number of persons employed/Number of lost time injuries) × 1000
B. (Number of lost time injuries/Average number of persons employed) × 1000
C. (Average number of persons employed/ Number of fatal injuries) × 1000
D. (Number of fatal injuries/Average number of persons employed) × 1000
Correct Answer: B
Solved Example: 9509-02
What is the purpose of a safety data sheet (SDS) in construction?
A. Providing instructions for construction project management
B. Outlining project specifications and requirements
C. Identifying and communicating hazards of materials used on the site
D. Ensuring compliance with local zoning regulations
The purpose of a Safety Data Sheet (SDS), formerly known as an MSDS, is to give emergency response personnel and users of hazardous compounds the right handling or operating methods for a specific substance.
Correct Answer: C
Solved Example: 9509-03
Which type of fire extinguisher is suitable for electrical fires on a construction site?
A. Class A
B. Class B
C. Class C
D. Class D
Correct Answer: C
Construction Equipment
Learning Objectives:
- Categorize construction equipment into various types, such as earthmoving, material handling, construction vehicles, and equipment for specific construction tasks (e.g., concrete placement, drilling, and compaction).
- Understand the factors that influence the selection and sizing of construction equipment, including project requirements, site conditions, and equipment capabilities.
- Identify common safety hazards associated with construction equipment operation.
Categories of Construction Equipment:
- Earth moving equipment: Power Shovel, Back Hoe, Dozres, Scrapers, Graders.
- Hauling equipment: Trucks, Semi Trailers
- Hoisting equipment: Mobile Cranes, Jacks, Tower Cranes, Whirler Cranes, Derrick Cranes
- Conveying equipment: Belts, Screw conveyors
- Aggregate and concrete production equipment: Crushers, Gyratory Crushers, Impact Crushers, Mixers and Batching Equipment
- Pile driving equipment: Pile Excavators, Pile Drivers
- Rock drilling equipment: Drillers with different capacities
- Dewatering equipment: Vacuum Filters, Sludge Lagoons, Drying Beds, Filters Presses
Cranes:
A crane is a mechanical lifting device that uses pulleys and cables to raise and lower heavy loads. It is an essential tool in construction and material handling.
Types of Cranes: Cranes come in various types, each suited to specific tasks and environments. Common types include:- Mobile Cranes
- Tower Cranes
- Crawler Cranes
- Overhead Cranes
- Gantry Cranes
- Boom: The arm of the crane that extends horizontally and carries the load.
- Hook or Grapple: The attachment that holds and lifts the load.
- Hoist: The mechanism responsible for raising and lowering the load.
- Counterweights: Used to balance the crane and prevent tipping.
- Cab or Operator's Station: Where the crane operator controls the crane's movements.
- Stabilizers: Supports that extend from the crane's base to provide stability.
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Asphalt Paver:
An asphalt paver is a construction machine used to lay a smooth and even layer of asphalt on road surfaces, parking lots, and other paved areas. Components of an Asphalt Paver:- Hopper: Stores and dispenses the asphalt mix.
- Conveyor: Transports the asphalt mix from the hopper to the auger.
- Auger: Spreads the asphalt mix evenly across the width of the road.
- Screed: Levels and compacts the asphalt mix, determining the final surface profile.
- Caterpillar Tracks or Wheels: Provide mobility and stability.
- Wheeled Pavers: These pavers have wheels and are suitable for smaller and less demanding projects, such as parking lots and driveways.
- Track Pavers: Track pavers are equipped with caterpillar tracks, which provide better traction and stability. They are commonly used for larger road construction projects.
Volvo Construction Equipment, CC BY-SA 4.0, via Wikimedia Commons
Compaction Road Rollers:
Compaction road rollers, commonly known as rollers or road compactors, are heavy construction machines used to compact soil, asphalt, or other construction materials to improve their density and load-bearing capacity.
Types of Compaction Rollers:- Smooth Wheeled Rollers: Equipped with smooth drums for compacting asphalt and other materials.
- Padfoot Rollers: Fitted with segmented pads on the drum for compacting cohesive soils.
- Pneumatic Rollers: Use rubber tires or pneumatic rollers to compact asphalt and fine-grained soils.
- Vibratory Rollers: Employ vibration mechanisms to enhance compaction.
- Drum: The large cylindrical drum is the main compaction component that makes contact with the material being compacted.
- Engine: Provides the power needed for the roller's movement and vibration (in the case of vibratory rollers).
- Operator's Platform: Where the operator controls the roller's movements and compaction parameters.
- Water System: Many rollers have a water system for wetting the material to improve compaction efficiency.
Pearson Scott Foresman, Public domain, via Wikimedia Commons
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Derrick Cranes, Biezl, CC BY-SA 3.0, via Wikimedia Commons
Solved Example: 9362-01
What is the equipment used for short haul distance of 100 m?
A. Bulldozer
B. Scrapper
C. Power shovel
D. Hoe
Correct Answer: A
Solved Example: 9362-02
The compaction of sand is done by ______.
A. Rollers
B. Animals
C. Vibrator
D. Jetting
Correct Answer: D
Solved Example: 9362-03
What of the following machines can be used for the top-soil removal?
A. Jackhammer drill
B. Scraper
C. Shuttle car
D. Shredder
Correct Answer: B
Solved Example: 9362-04
Which of the following is NOT a type of crane?
A. Whirler
B. Johnson
C. Gantry
D. Derrick
Correct Answer: B
Solved Example: 9362-05
Which equipment is used to level the ground and spread the loose material?
A. Power shovel
B. Bulldozer
C. Grader
D. Dragline
Correct Answer: C
Solved Example: 9362-06
The arrangement made to support an unsafe structure temporarily is known as:
A. Shoring
B. Scaffolding
C. Underpinning
D. Jacking
Correct Answer: A
Solved Example: 9453-01
What is the primary function of a crawler excavator in construction?
A. Paving asphalt surfaces
B. Lifting and placing heavy loads
C. Digging and excavating soil
D. Compacting soil and aggregates
Correct Answer: C
Solved Example: 9453-02
Which type of construction equipment is commonly used for lifting and placing heavy materials or equipment at construction sites?
A. Backhoe loader
B. Tower crane
C. Bulldozer
D. Motor grader
Correct Answer: B
Solved Example: 9453-03
What is the primary purpose of a vibratory roller in construction?
A. Excavating trenches
B. Spreading asphalt
C. Compacting soil or asphalt surfaces
D. Lifting and transporting heavy materials
Correct Answer: C
Solved Example: 9453-04
In construction, what role does a backhoe loader typically perform?
A. Excavation and digging
B. Lifting and placing heavy loads
C. Grading and leveling surfaces
D. Compacting soil and aggregates
Correct Answer: A
Solved Example: 9453-05
Which construction equipment is specifically designed for spreading and leveling asphalt or concrete surfaces during road construction?
A. Motor grader
B. Crawler excavator
C. Concrete mixer truck
D. Paver machine
Correct Answer: D
Productivity Analysis
Learning Objectives:
- Learn the various productivity metrics used in civil engineering, such as labor productivity, equipment productivity, and material productivity.
- Identify the key factors that influence productivity in construction and civil engineering, including labor, equipment, materials, project complexity, and site conditions.
Major causes of poor productivity:
- Congestion
- Sequencing
- Lack of Materials
A high variability in the unit productivity value is an indication of poor productivity.
Factors Affecting Productivity:- Various factors influence construction productivity, including labor skills, equipment reliability, work methods, weather conditions, and project complexity.
- Labor productivity can be affected by factors like worker morale, fatigue, and motivation.
Implement strategies to improve productivity, such as better workforce training, enhanced equipment maintenance, optimized project planning, and efficient resource allocation.
Temporary Erosion Control
Learning Objectives:
- Identify common temporary erosion control measures, such as silt fences, sediment basins, straw bales, silt socks, and rock check dams.
- Understand their functions, appropriate applications, and limitations.
Erosion is the process of soil or rock wearing away by natural forces, such as water and wind. In construction, it can be accelerated due to disturbed soil. Sediment control involves managing the deposition of soil particles eroded from construction sites, preventing their entry into water bodies.
Temporary erosion control measures are essential to prevent soil erosion and sediment runoff from construction sites. Uncontrolled erosion and sedimentation can lead to environmental damage, water pollution, and non-compliance with regulations.
Common temporary erosion control measures include silt fences, sediment basins, straw bales, silt socks, and rock check dams. These measures are strategically placed to intercept and detain sediment-laden runoff.
U.S. Environmental Protection Agency (EPA), Public domain, via Wikimedia Commons
Illustration of a fiber roll installation on a construction site, from U.S. EPA publication, "Developing Your Stormwater Pollution Prevention Plan: A Guide for Construction Sites." Document No. EPA-833-R-060-04.
Solved Example: 9363-01
Study the following statements:
(i)Levees are constructed parallel to the river flow.
(ii)Spurs are constructed parallel to the river flow.
(iii)Levees are constructed transverse to the river flow.
(iv)Spurs are constructed transverse to the river flow.
The correct answer is:
A. (iii) and (iv)
B. (iv) and (i)
C. (i) and (ii)
D. (ii) and (iii)
Correct Answer: B
Solved Example: 9363-02
The main cause of meandering is due to the___________.
A. Presence of an excessive bed slope in the river
B. Extra turbulence generated by the excess of river sediment during floods
C. Degradation
D. None of the above
Correct Answer: B
Solved Example: 9363-03
Meandering of a river is due to:
A. Sediment load of streams
B. Discharge and hydraulic properties of streams
C. Erodibility of the bed and banks of stream
D. The natural topography of the location
Correct Answer: C
Solved Example: 9363-04
Guide banks are provided in rivers to:
A. Increase the depth of flow in the river
B. Decrease the velocity of flow of the river
C. Channelise the flow of the river
D. Reduce the flood peak
Correct Answer: C
Solved Example: 9363-05
Among the following river training works, which are aligned either parallel or at an angle to the banks, identify the one having a difference in alignment when compared to others.
A. Groynes
B. Guide banks
C. Levees
D. Flood walls
Correct Answer: A