Construction methods and equipments

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Prepared by R.Vijayakumar, B.Tech (CIVIL), CCET, Puducherry

CONSTRUCTION METHODS AND EQUIPMENTS

UNIT – 1

1. Define excavation. What are the methods are used in excavations?

Excavation work generally means work involving the removal of soil

or rock from a site to form an open face, hole or cavity using tools,

machinery or explosives. Excavation has a number of important applications

including exploration, environmental restoration, mining and construction.

The two methods of excavations are,

Mass excavation

Structural excavation

2. What are the problems normally developed during deep excavations?

To prevent the collapsing of sides of the trenches

To prevent water oozing or coming out from the sides and bottom of

the trenches

3. What are the remedial measures to avoid the problems in deep

excavation?

Providing shoring for the trenches

Dewatering of the trenches

4. Define foundation.

Foundation is a part of the structure which is present below the ground

level. It supports the weight of the structure and the load carried by it. The

type of the foundation depends upon the bearing capacity of the soil.

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5. What are the types of foundation?

Shallow foundation

Spread foundation

o Strip footing

Simple footing

Stepped footing

o Column footing

Isolated column footing

Combined column footing

Raft foundation

Grillage foundation

Deep foundation

Pile foundation

Pier foundation

Well foundation

6. Define pier foundation.

A pier foundation consists of a cylindrical column of large diameter to

support transfer large super imposed loads to the firm strata below.

Generally pier foundation is shallower in depth than the pile foundation. It

has two types.

Masonry pier

Concrete pier

7. What are the types of caisson?

Open caisson

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Box caisson

Pneumatic caisson

8. What is caisson?

Caissons are structural boxes or chambers. These are sunk in place

through the ground or water by excavating below the bottom of the unit

which enables the caisson to reach the final depth.

These structures have a large cross – sectional area and hence provide

high bearing capacity, which is much larger than what may be offered by a

cluster of piles.

9. What are the materials used for construction of caissons?

Cast iron

Reinforced Cement Concrete

Steel

Timber

10. Give the uses of caissons.

To reach the hard bearing structure for transferring the load coming

on support for bridge piers and building columns

To serve as an impervious core wall of earth dams When placed

adjacent to each other

To provide an access to a deep shaft or a tunnel

11. What are the operations involved in open caisson method of

foundation?

Constructing or fabricating the caisson and preparing site to receive it

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Placing the caisson over the site of the pier

Excavating the soil from the interior of the caisson and advancing the

caisson so than its cutting edge is at or below the bottom of the

excavation

Continuing this process until the foundation in the hard stratum is

reached

Sealing the bottom of the caisson to exclude water and soil

12. Define box caisson.

It is open at the top and closed at the bottom and is made of timber,

reinforced concrete or steel. This type of caisson is used where bearing

stratum is available at shallow depth.

13. Define open caisson.

Open caisson is a box opened both at top and bottom. It is made up of

timber, concrete or steel. The open caisson is called well. Well foundation is

the most common type of deep foundation used for bridges in India.

14. Define pneumatic caisson.

Pneumatic caissons has its lower end designed as a working chamber

in which compressed air is forced to prevent the entry of water and thus

excavation can be done in dry conditions.

15. Define basement.

Basement or cellar is the lower storey of a building constructed or

partly below the ground surface.

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16. Define basement construction.

Construction of basement is difficult for it must be carried out below

deep ground in adverse condition such as existence of ground water,

muddiness or limited working space. Besides, works are needed to be done

amidst layers of props, struts, waling and shores, which cannot be removed

until the permanent works are completed and capable of carrying the final

loads.

17. What are the methods of basement constructions?

Use of lattice beams

Use of ground anchors

Construct floor slab as support (top down method)

Cast the centre basement slab to support struts

In – situ reinforced concrete and tradition formwork system

18. Define braced wall. What are the types of braced wall?

A braced wall is a structural system composed of braced panels (also

known as shear panels) to counter the effects of lateral load acting on a

structure. Wind and seismic loads are the most common loads that braced

walls are designed to carry.

TYPES:

Single diagonal

Double diagonal

Chevron bracing

Storey height knee bracing (eccentricity braced frames)

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19. Define soil nailing. What are the types of soil nail wall?

Soil nailing is an earth retention technique using grouted tension-

resisting steel elements (nails) that can be design for permanent or temporary

support. The walls are generally constructed from the top down. Typically, 3

to 6 feet of soil is excavated from the top of the planned excavation.

TYPES:

Grouted soil nailing

Driven nails

Self-drilling soil nail

Jet grouted soil nail

Launched soil nail

20. What are the applications of soil nail wall?

Roadway cuts

Road widening under existing bridge abutments

Tunnel portals

Repair and reconstruction of existing retaining structures

Hybrid soil nail systems

Shored Mechanically Stabilized Earth (SMSE) walls

21. What are the advantages of soil nail wall?

Creates less noise and traffic obstructions

Less impact on nearby properties

Allow excellent working space in front of the excavation face

Can be used for strengthening of either natural slope, natural or man –

made cut slopes

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Grouting only once is required, saving time and labor

The technique is flexible, easily modified

22. What are the disadvantages of soil nail wall?

Nail encroachment to retained ground rendering unusable

underground space

Generally larger lateral soil strain during removal lateral support and

ground surface cracking may appear

Tendency of high ground loss due to drilling technique, particularly at

course grained soil

Less suitable for course grained soil and soft clayey soil, which have

short self-support time, and soils prone to creeping

Suitable only for excavation above groundwater

23. Define sheet pile wall. What are the types of sheet pile wall?

A sheet pile wall consists of a series of sheet piles driven side by side

into the ground, thus forming a continuous vertical wall for the purpose of

retaining an earth bank. They are commonly used for water front structures,

temporary construction and light weight construction where sub – soil is

poor for supporting a retaining wall. A sheet pile wall may be of three types.

They are,

Cantilever sheet piling

Anchored sheet piling

Braced sheeting

24. Give the different types of sheet piles based on materials.

Concrete sheet pile

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Timber sheet pile

Steel sheet pile

25. Write the functions of sheet piles.

To enclose a site or part thereof to prevent the escape of loose subsoil,

such as sand, and to safeguard against settlement.

To retain the sides of the trenches and general excavation.

To protect river banks.

To protect the foundations from scouring actions of nearby river,

stream etc. To construct costal defense works

26. What are the uses of sheet pile?

To protect river banks

To retain the sides of foundation trenches

To resist flow of underground or loose soil or of both

To resist bending abrasion or other stresses which may arise in use

27. Define dewatering.

Dewatering means removal of excess water from the saturated soil. It

is used where the water table is high or in the case of deep excavations the

foundation trenches for buildings and other structures, are filled with seeped

water.

28. What are the methods of ground water control?

Pumping from open sumps

Pumping from well points

Pumping from bored wells

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29. What are the methods of dewatering?

Ditches

Well point system

Shallow well system

Deep well system

Vaccum method

Electro osmosis method

30. Write the essential features of a pump to be used for dewatering.

The pump should be portable so that it can be easily moved as and

when required

The pump should be capable of handling water mixed with impurities

such as sand, earth, etc.

The pump should be of strong make

The performance of pump should be reliable

31. What are the methods of water proofing?

Cementitious water proofing

Liquid water proofing membrane

Bituminous membrane

Bituminous coating

Polyurethane liquid membrane

32. Define trenching.

A trench is defined as a narrow excavation (in relation to its length)

made below the surface of the ground. In general, the depth of a trench is

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greater than its width, but the width of a trench (measured at the bottom) is

not greater than 15 feet (4.6 m).

33. What are the types of trenching?

Single slot trenching

One side stepped trenching

Two side stepped trenching

Multi stepped trenching

One side sloped trenching

Two side sloped trenching

34. What are the advantages of using trenchers?

It is faster and cheaper method of trenching

It digs only as much as is necessary

A 10cm pipe can be installed in a 15cm wide slot cut by a trencher

It is a continuous process and is not like that of backhoe excavator

(i.e.) dug lift – dump

35. On what basis you will select the equipment for the construction?

Volume of the material to be removed

Size of the machine used

Depth of excavation

Height to be lifted

Soil type

Duration of period

Rented or purchased

Production cost

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Spares availability

Skilled operation

36. What are the types of earth moving equipment for construction?

Production equipment

Equipment used for digging and moving

Service equipment

Dozers and motor girders

37. List out the material handling devices.

These are the lifting and lowering devices (vertical motion).

Block and tackle

Winches

Hoists

Elevators

Pillar crane

Overhead crane

38. List out the transportation devices (horizontal motion).

Wheel borrows and hand truck

Narrow gauge mine rail road

Tractors and trailers

Skids

Pipe line

39. List out the applications of motor grader.

Land clearance

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Snow clearance

Material mixing

Hard surface cutting

Ditch filling or digging

Bank cutting and reshaping

40. What are the devices used for combination of lifting, lowering and

transportation operations?

Spiral chute

Lift track

Crane truck

Forklift truck

Conveyors of various types

41. What is a tractor? Mention its types.

Tractor is earthmoving equipment which converts engine energy into

tractive energy. The two types of tractors are,

Crawler or tract type

Wheel or pneumatic type

42. What are the factors to be considered while selecting a tractor?

Size of the dozer for a given job

The type of work expected from the tractor dozer

Example: bulldozing, ripping, land clearing, pulling a scraper

The type and condition of hauled road

Gradient of the haul road

Distance to be moved

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Type of work expected to be taken from the equipment after the

present job is completed

43. What are the advantages of crawler excavator?

More tractive effort, hence can also operate on loose or muddy soil

In absence of tyres, can easily operate in rocky conditions, as there is

no danger for the damage of the tyres

Where maintenance of haul roads is difficult, it can be easily travel,

especially in rough terrains

Crawler tractors are more compact and powerful and hence can handle

difficult jobs as well

44. What are the advantages of wheeled tractors?

Can travel at higher speeds during the operation and also from one job

to another

Can travel long distance at its own power, whereas crawler mounted

needs trailers

When work is spread over long area, there are found to be producing

more output

Easy in operation. Operation feels less fatigue.

45. What are the uses of excavators?

Digging of trenches, holes and foundations

Material handling

Brush cutting with hydraulic attachments

Forestry work

Demolition

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General grading/landscaping

Heavy lift, e.g. lifting and placing of pipes

Mining, especially, but not only open-pit mining

River dredging

Driving piles, in conjunction with a Pile Driver

46. List out the types of excavators.

Compact excavator

Crawler excavator

Wheeled excavator

Backhoe loader

Dragline excavator

Bucket wheel excavator

Long reach excavator

Power shovel

Suction excavator

47. What are the main uses of a bulldozer?

Clearance of shrubs and small trees

Clearance of trees by using raised mould blade as a pusher arm

Acting as a towing tractor

Acting as a pusher to scraper machines

48. What are the applications of bulldozer?

Land clearing

Stripping

Side hill cuts

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Ditching

Spreading

Dozing rocks and frozen ground

Maintaining haul roads

Clearing the floors of borrow and quarry pits

49. Differentiate between crawler and pneumatic types of wheels.

CRAWLER TYPE WHEEL PNEUMATIC TYPE WHEEL

The crawler moves on an endless

chain

It moves on pneumatic tyres

They are slow speed They are faster in speed

They are used for uneven & rough

ground

They operate best on smooth roads

They have a speed of about 12kmph They have a speed of about 50kmph

50. What is motor grader?

Motor graders are used for leveling and smoothening of the

earthwork, spreading and leveling the base courses in the construction of

roads and airfield. It can be used for land reclamation, snow clearance,

gravel road repairing, mixing of stabilizing materials such as tar, asphalt,

cement and lime, maintaining quarry roads, etc.

51. What is a scraper?

Scrapers are the device to scrap the ground and load it simultaneously,

transport it over the required distance, dump at desired place and then spread

the dumped material over the required area in required thickness level, and

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return to the pit for the next cycle. The scrapers are of three types. They

are,

Towed type

Self-propelled or motorized

Self-loading or elevating scraper

52. What are the three types of scraper?

Crawler drawn scraper

Two axle scraper

Three axle scraper

53. What are the advantages of elevating scraper?

Better loading ability in loose free flowing materials

Good finishing ability

Can be operated independently

Pusher tractor dozer is not required

Smooth and complete unloading of bowl by reversing the elevator

rotation

Pulverizing and mixing action by the elevator places material in

uniform and homogeneous state for compaction.

54. Write short note on skimmers.

These excavators are rigged using a universal power unit for surface

stripping and shallow excavation work upto 300mm deep where a high

degree of accuracy is required. They usually require attachment haulage

vehicles to remove the spoil and need to be transported between sites on a

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low loader. Because of their limitations and the availability of alternatives

machines, they are rarely used today.

55. What are the factors governed the output of a dragline?

Output or the performance of the dragline depends on the following

factors,

Nature of soil

Depth of cut

Angle of swing

Capacity of hauling units, if employed

Mechanical condition of the dragline

Efficiency and skill of the operator

56. Write short notes on draglines.

Cranes are machines designed to move materials vertically (rise by

rope pulley operation) or horizontally. The range of cranes available is very

wide, from gear wheel to a complex tower crane. Therefore, choice must be

based on:

The loads to be lifted

Height of lifting

Horizontal distance to be covered

Time period of lifting operations

Utilization factors and

Degree of mobility required

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57. What is the power shovel?

It is used to excavate the earth of all classed and load it into wagons.

They are mounted on crawler tracks. It consists of a mountain, cab, boon,

dipper, strip, hoist line.

58. What is a clamshell?

Clamshell is a machine having most of the characteristics of dragline

and crane in common. Digging is done like a dragline and once the bucket

is filled, it works like a crane. It is very useful for accurate spot dumping of

material in a confined space in a vertical plane. It can be used for handling

of loose or soft and medium hard materials only.

59. What are the methods of underwater concreting?

Tremie method

Pump method

Toggle bags

Bags work

60. What are the types of temporary earth retaining structures?

Braced wall

Sheet pile wall

Soil nail wall

61. Define blasting.

Blasting is the process of discharging of an explosive to loosen the

rock.

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62. What are the parameters to be examined while blasting for quarrying?

While blasting for quarrying or excavation, the following parameters

are to be examined.

Spacing of the drill holes

Diameter of the drill holes

Depth of the drill holes

Burden of the rock at the toe

Burden of the rock at the crest

Degree of fragmentation desired and

Strength of the explosives to be used

63. Define dredging.

It is the process of excavating from river bed, lake or sea for the

purpose of deepening them. It is an important operation in navigation

canals, harbors, dams etc.

64. What are the types of dredgers?

Dipper dredger

Ladder dredger

Suction dredger

65. What is line system?

This system is employed when excavation area is long. The header is

laid out along the sides of the excavation, and the pumping is continuously

in progress in one length as further points are jetted ahead of the pumped

down section and pulled up from the completed and back filled lengths and

repeated till entire length is completed. For narrow excavation, like trenches,

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header is laid only on one laid, while for wide excavations, the header are

required to be placed on both sides of the area.

66. What is ring system?

When excavation is done in area of appreciable width, line system is

inadequate. The ring system is used in such condition and the header main

surrounds the excavations completely. This system is used for rectangular

excavations such as for piers or basements.

67. Where is grout anchors used in constructions?

In most cases, however anchorages may be embedded below ground

level, with backstays connecting them to adjacent towers, or they may

constitute the end abutments of the end spans. In addition to stability sliding,

the anchorage structure must also be checked for stability against tilting and

overturning.

68. Define texture. What are their classifications?

Texture is defined as the grain size of the rock. It is classified into 5

categories such as,

Porous rock

Loose grained rock

Granitoid rock

Fine grained rock

Dense rock

69. List out the construction equipment.

Bull dozers

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Graders

Skimmers

Scrapers

Loaders

Face shovels

Backhoe

Draglines

70. Mention the various operations involved in grading.

Grading

Spreading

Finishing and leveling

Ditch digging

Cutting

Bank cutting

Earthen road maintenance

Earthen road construction

Repairing gravel road

UNIT – 2

1. Define pile foundation.

A pile is a slender column made of wood, concrete or steel. A pile is

either driven into the soil or formed in situ by excavating a hole and then

filling it with concrete. A group of piles are driven to the required depth and

are capped with R.C.C. slab, over which super structure is built. The pile

transfer the load to soil by friction or by direct bearing, in the latter case,

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piles being taken up to hard strata. This type of foundations is used when top

soil is not capable of taking the load of the structure even at 3–4 m depth.

2. Write the situations under which pile foundation is recommended.

When spread footing, raft and grillage foundations are uneconomical

When heavy concentrated loads are to be transmitted by the

foundation

Where there is scouring in the soil near the foundations

Where the soil is made up and of a compressible nature

3. Give the different types of piling.

Rotary board technique

Continuous flight auger piling

Low head room continuous auger pile

Cased flight auger piling

4. What is the equipment used for driving a pre – cast pile in a sandy soil?

The equipment used for driving a pre-cast pile in a sandy soil is a

hammer. Hence maximum stresses are developed at the top due to direct

strokes and at the point in overcoming the resistance to penetration.

Therefore additional reinforcement is provided.

5. Define well foundation. What are the types of well foundation?

Well foundation is a type of deep foundation which is generally

provided below the water level for bridges. Well foundation is a box of

timber, metal, reinforced concrete or masonry which opens both at the top

and bottom, and is used for building and bridge foundations. Well

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foundations are being used in India from very early days. TajMahal was

built on such foundations.

TYPES:

Open caisson

Single wall open caisson

Cylindrical open caisson

Open caisson with dredging wells

Box caisson

Pneumatic caisson

6. What is well cap?

It is a RCC slab laid at the top of the well Steining. It transfers the

load to the Steining.

7. What are the components of well foundation?

The components of well foundations are,

Well curb

Cutting edge

Steining

8. What is a Kent ledge?

In well sinking, to overcome the increased skin friction and the in

weight of the well due to buoyancy, additional loading is applied on the

wall. It is called Kent ledge.

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9. What is cofferdam?

Cofferdams are temporary or permanent structure which is

constructed so as to remove water / soil from an area and make it possible to

carry on the construction work under reasonably dry conditions. These are

constructed by driving sheet piles in the form of cells which are filled with

granular materials and become self-stabilizing retaining structures.

10. What are the factors you will consider while selecting cofferdams?

The area to be protected by a cofferdam.

The depth of coater to be dealt with shallow depth or deep depth.

The possibility of overtopping by floods, tides, etc.

The nature of bed on which the cofferdam is to test, (i.e.) previous

layer or an impervious layer.

11. What are the uses of cofferdam?

To facilitate pile driving operations

To place grillage and raft foundations

To construct foundations for piers and abutments of bridges, dams,

locks, etc.

12. What are the types of cofferdams?

The types of cofferdams are,

Dikes

Single wall construction

Double wall construction

Cellular cofferdam

Rock filled

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Concrete cofferdam

Suspended cofferdam

13. Define shoring.

Shoring is the construction of a temporary structure to support

temporarily an unsafe structure. These support walls laterally.

14. What are the types of shoring?

Depending upon their supporting characteristics the shores are

classified into 3 categories.

Racking or inclined shores

Flying or horizontal shores

Dead or vertical shores

15. Why is shoring provided in foundation?

When a wall cracks due to unequal settlement of foundation and the

cracked wall needs repair. So, shoring is provided in foundation.

16. Under what circumstances shoring is provided?

When walls bulge out

When walls crack due to unequal settlement of foundation and repairs

are to be carried out to the cracked wall

When an adjacent structure needs pulling down

When openings are to be newly made or enlarged in a wall

17. What are the methods of providing shoring for the trenches?

Stay bracing

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Box sheeting

Vertical sheeting

Runners

Sheet piling

18. Define wales.

The depth of sheeting is held in position by means of horizontal

beams called wales.

19. Define rakes.

If the excavation is too wide, the wales may be supported by inclined

struts known as rakes.

20. Define struts.

Strut is a compression member to provide temporary support to in-situ

retaining walls in deep excavations. It is mostly a steel beam of various

sections or a pipe. Reinforced concrete beams are seldom used.

21. Define underpinning.

The process of placing a new foundation under an existing one or

strengthening and existing foundation is called underpinning.

22. What are the types of underpinning?

Pit method

Pile method

Chemical method

Other methods

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23. Define diaphragm wall.

Diaphragm wall are structure elements, which are constructed

underground to prevent the seepage into the excavated area.

24. Define RCC diaphragm wall.

Diaphragm Wall is generally reinforced concrete wall constructed in

the ground using under slurry technique which was developed in Europe.

The technique involves excavating a narrow trench that is kept full of an

engineered fluid of slurry. Walls of thickness between 300 and 1200 mm

can be formed in this way up to depths of 45 meters.

25. When is diaphragm wall used?

A diaphragm wall is basically a deep trench excavated in soil in to

which reinforced concrete is placed. Diaphragm walls are used in

permanent and temporary foundation walls for deep basements in earth

retention schemes for highway and tunnel projects, as permanent walls for

deep shafts for tunnel access, and as permanent cut – off walls through the

care of earth dams.

26. Write down the construction procedure of diaphragm wall.

Fixing of alignment

Guide wall construction

Trenching

Trench cleaning

Stop ends fixing

Reinforcement cage lowering

Placing of concrete

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Withdrawal of stop ends

27. What are the various methods adopted to construct a diaphragm wall?

Slurry trench technique

Soil mixing method

RC continuous diaphragm wall

Precast diaphragm wall

Glass diaphragm wall

28. Give the uses or applications of diaphragm wall.

Commonly used in congested areas.

Can be installed in close proximity to existing structure.

Practically suited for deep basements.

Used in conjunction with “Top Down” construction technique.

UNIT – 3

1. Define scaffolding.

These are temporary erections constructed to support a number of

platforms at different heights raised for the convenience of workers so as to

enable them to work easily and raise the needed materials.

2. What are the component parts of scaffolding?

Standards

Ledgers

Braces

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Putlogs

Transoms

Bridle

Boarding

Guard rail

Toe board

3. Give the materials used for formwork.

Formwork can be made out of timber, plywood, steel, precast

concrete, fibre glass, used separately or combination.

4. When the removable of formwork are done?

The form should be removed until the concrete has hardened

sufficiently and they may be left in place for as possible up to maximum

days of 28 in normal weather conditions. A hard metallic sound indicates

the concrete has hardened sufficiently for safe removal of formwork.

5. State briefly the essential requirements of formwork.

It should be strong enough to withstand all loads coming on it, such a

dead load of concrete and live load during its pouring, compaction and

curing.

It should be stiff enough so that deflection is minimum

It should be as be light as possible

This form work should rest on non – yielding supports

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6. Define centering and shuttering.

Part of the form work which supports the horizontal surface is called

centering for example slab bottom, beam bottom etc.

Part of the form work which supports the Vertical surface is called

Shuttering for example column sides, beam sides, slab side, wall side etc.

7. Define hoisting.

A hoist is a device used for lifting or lowering a load by means of a

drum or lift-wheel around which rope or chain wraps. It may be manually

operated, electrically or pneumatically driven and may use chain, fiber or

wire rope as its lifting medium. The load is attached to the hoist by means of

a lifting hook. There are three types of hoist namely,

Wire rope or chain hoist

Construction hoist

Mine hoist

8. Define rigging.

Rigging is the apparatus through which the force of the wind is used

to propel sailboats and sailing ships forward. This includes masts, yards,

sails, and cordage.

9. What are the types of cranes?

Overhead crane

Truck mounted crane

Side lifter crane

Rough terrain crane

All terrain crane

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Pick and carry crane

Carry deck crane

Telescopic handler crane

Crawler crane

Harbor crane

Railroad crane

Floating crane

Aerial crane

Tower crane

Level luffing crane

Gantry crane

Deck crane

Bulk handling crane

Stacker crane

10. Define plastering.

The process of covering the surfaces of masonry, beam or column

with mortar is called plastering. Mortar is a substance obtained by mixing

sand, a binding material (cement/lime) and water in definite proportions.

11. Define flooring. What are the types of flooring?

Flooring is the horizontal area in any floor of a building that is

actually the space used by the occupants for moving in the building.

TYPES OF FLOORING:

Mud flooring

Cement concrete flooring

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Terrazzo flooring

Mosaic flooring

Glazed tile flooring

Marble flooring

Linoleum flooring

Brick flooring

Stone flooring

Granolithic flooring

Timber flooring

Asphalt flooring

Rubber flooring

Epoxy resin flooring

12. What are the requirements of good flooring?

Low cost

Good appearance

Sound and thermal insulation

Strength and durability

Smoothness

Damp and fire resistance

Comfortability

Anti-skid

13. Give some aspects you consider while choosing the floor type.

Initial cost

Appearance

Cleanliness

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Durability

Damp resistance

Sound insulation

Thermal insulation

Smoothness

Hardness

Fire resistance

Maintenance consideration

14. What are the components of flooring?

Sub floor or base course

Floor covering

15. Define aggregate crushers and screening equipment.

Screening is the separation of material into 2 - 6 different sized

products. The material is separated by passing it through a vibrating 'screen

box' which a number of different has sized screens, or meshes, which the

material falls through like a sieve. The material falls onto attached

conveyors which stock piles the end products. The end products can then be

used in the building and construction industries.

16. Define aggregate feeders.

Aggregate feed bins are used for each of the size of the aggregate and

sand, and control their quality, weighting system is used for important jobs,

since control by volume is not perfect as it varies due to closeness of

packing of the material. The aggregate fed bins are loaded by any of the

following methods

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By shovels directly into the bins

By lorries tipping directly into the bins

Aggregate are stored in bulkhead at ground level

17. Define batching.

The measurement of materials for making concrete is known as

batching. There are two methods of batching.

Volume batching

Weight batching

18. What are the methods of equipment are used by volume batching?

Aggregate feeders

Cement silo

Water measuring device and

Mixing unit

19. Define mixing.

After measuring the materials required for preparing the concrete it

has to be mixed well before placing the concrete. It should ensure that the

mass becomes homogeneous and uniform. There are two methods of

mixing.

Hand mixing

Machine mixing

20. What are the methods are adopted for transportation of concrete?

Mortar pan

Wheel barrow

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Crane, bucket and rope way

Truck mixers and dumpers

Belt conveyors

Chute

Skip and hoist

Transit mixer

Pump and pipe line

Helicopter

21. What is meant by transit mixer?

Transit mixer is a piece of equipment that is used for transporting

concrete, mortar or ready mix material from a concrete batching plant

directly to the site where it is to be utilized. Transit mixer is loaded with dry

material and water. The interior of the transit drum is fitted with a spiral

blade.

22. What are the types of conveyors?

Belt conveyors

Roller conveyors

Chain conveyors

Pipe conveyors

Elevating conveyor

23. What are the advantages of using belt conveyors?

Its suitable levels eliminate a good deal of lifting and lowering of

material.

It require no stopping or standing but is continuous operation.

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Transportation is affected by friction between material being

transported and the belt.

It largely saves labor cost.

No noise

Carry the material horizontal, vertical, inclined.

It can withstand 1600 C.

24. What are the activities normally followed during concreting?

Batching

Mixing

Transporting

Placing

Compacting

Curing

25. Define compaction.

Compaction is defined as the process of densifying or increasing the

unit weight of a soil mass through the application of static or dynamic force,

with the resulting expulsion of air.

26. What are the factors influencing compaction?

Drum diameter

Frequency and amplitude

Relationship between frame and drum weight

Driven or non-driven drum

Centrifugal force

Total applied force

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Static weight

Number of vibratory drums

Roller speed

27. Name some compaction equipment.

Towed static smooth compactors

Static sheep foot or pad foot compactors

Static three wheel self-propelled compactors

Static tandem compactors

Three axle static compactors

Rubber tyred compactors

Vibrator compactors

Tandem vibrator compactors

Towed vibrator compactors

Sheep foot & tamping foot vibrator compactors

Self-propelled vibrator compactors

Hand guided vibrator compactors

28. What are the various types of concreting equipments?

Concrete mixers

Concrete hauling equipments

Wheel barrows

Dumpers

Ready mix concrete mixers

Concrete pumps for placement in different conditions

Concrete vibrators for compaction

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Poker or internal vibrator

External clamp or tamping board vibrator

29. Define shotcreting.

Mortar or high performance concrete conveyed through a hose and

pneumatically projected at high velocity onto a backing surface is known as

shotcreting.

30. How pumps are classified?

Positive displacement pump

Reciprocating pump

Rotary pump

o Gear pump

o Vance pump

o Screw pump

Rotodynamic pump

Volute pump

Circular pump

Diffuser pump

Vertical turbine pump

Centrifugal mixed flow pump

Propeller pump

31. Define drilling.

Drilling is a cutting process that uses a drill bit to cut a hole of circular

cross-section in solid materials. The drill bit is a rotary cutting tool, often

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multipoint. The bit is pressed against the work piece and rotated at rates

from hundreds to thousands of revolutions per minute. This forces the

cutting edge against the work piece, cutting off chips (swarf) from the hole

as it is drilled.

32. What are the types of drilling equipment?

Percussion drills

Rotary drills

Pressure drilling

Abrasion drilling

33. What are the factors affecting the selection of drilling equipment?

Nature of terrain

Required depth of holes

Rock hardness

The purpose for which holes are required to be drilled (i.e.) for

blasting or grouting or for exploration purposes

The size of the project

34. What are the methods used for building demolition techniques?

Manual method

Mechanical method

Demolition by machine

Demolition by hydraulic rushers

Demolition by wrecking ball

Explosive method

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35. What are the methods used for tunnel driving?

Full face method

Top Heading and benching method

Drift method

Pilot tunneling

Needle beam method

36. What are the factors you will consider while selection of route in

tunneling?

Geological conditions

Right of way

Alignment restraints

Environmental considerations

37. Give the various methods of tunneling through soft ground.

Fore poling method

Needle beam method

Five piece set method

Other methods

Casting methods

Square sets and logging method

Horse cups method

38. Give the various methods of tunneling through rock.

Full face method

Top heading and benching method

Cantilever car pump method

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Drift method

Pilot tunneling

UNIT – 4

1. Define bridges. What are the types of bridges?

A bridge is a structure constructed to provide the passage for a road or

railways over an obstacle such as river, valley etc. without closing a wall.

Masonry arch bridge

Reinforced cement concrete bridge

Slab bridge

T – beam bridge

Hollow girder bridge

Balanced cantilever bridge

RCC arch bridge

Steel bridge

Plate girder bridge

Steel arch bridge

Cable stayed bridge

Suspension bridge

Cantilever bridge

2. What are the types of sub structure?

Foundation

Abutment

Pier

Wing walls and return walls

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Revetment

Apron

Approaches to bridge

3. What are the types of super structure?

Bearings

Deck

Hand rails

Girder or truss

Roadway

4. Define abutment.

The abutment is a terminal support of the bridge. It is built on either

side of a valley where the road or railway joins the bridge.

5. Define pier.

In a multispan bridge piller like supports are constructed between the

abutments. These supports are called piers.

6. Define multispan bridge.

In a multispan bridge there are several piers and hence several spans.

The multispan bridges are built in the middle or lower reaches of rivers

where the valleys are generally very wide.

7. Define suspension bridge.

A bridge which is suspended with the help of cables and steel towers

across a deep and narrow river valley is called suspension bridge.

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8. Define RCC bridges. What are the types of RCC bridges?

Reinforced Cement Concrete is well suited for the construction of

bridges in the small and medium span ranges. Different types of RCC

bridges which are usually constructed are: Slab bridges, T – beam (girder

and slab) bridges, hollow girder bridges, balanced cantilever bridges,

continuous girder bridges, rigid frame bridges, arch bridges and bowstring

girder bridges.

9. What are factors to be considered for selection of site for bridges?

Span of the bridge and number of spans

Purpose of bridge

Intensity of loading on the bridge

Type of super structure adopted

Headroom to be provided below the bridge

Type of foundation soil, available

Nature of material used

Nature of alignment

Relative position of floor of the bridge

Prevailing wind force and earth – quake possibilities

Life expectancy of the bridge.

10. Define cable stayed bridges. What are the types of cable stayed bridges?

This type of bridge is especially suited for spans ranging from 200 to

500m. The main component of a cable stayed bridges are,

Inclined cables

Towers

Decks

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In a simple form the cables are provided above the deck and

connected to towers. This eliminates intermediate piers and provides large

width for the purposes of navigation. The deck is supported by a number of

cables. This type of bridge is widely used in recent years because of the

availability of high strength steel.

11. What are balanced cantilever bridges?

Providing continuous spans can minimize the bending moment and

hence individual span lengths can be increased. But this requires unyielding

supports. Any yielding of supports results in distress in structure. In order

to avoid this, a combination of cantilever and suspended spans may be

adopted. The bridge with this type of super structure is referred to as

balanced cantilever bridges. This type of bridge is suitable for medium span

in the range of about 35 to 60m.

12. What are the erection methods of launching of heavy deck?

Balanced cantilever erection method

Progressive placing method

Span by span (or) Steeping form work method

Incremental launching method

UNIT – 5

1. Define roads. What are the types of roads?

Road is specially prepared path on which the transport vehicles pass

lawfully.

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CLASSIFICATION OF ROADS ACCORDING TO LOCATION AND

FOUNDATION:

National highway

State highway

Major district roads

Other district roads

Village roads

CLASSIFICATION OF ROADS BASED ON MATERIALS USED:

Earth roads

Gravel road

Water Bound Macadam road

Bituminous road

Asphalt road

Cement concrete road

2. Define flexible pavements. What are the types of flexible pavements?

Flexible Pavements are those, which on the whole have low or

negligible flexural strength and are rather flexible in their structural action

under the loads. The Flexible Pavements layers reflect the deformation of

the lower layers on to the surface of the layer.

TYPES:

Conventional layered flexible pavement

Full depth asphalt pavement

Contained Rock Asphalt Mat (CRAM)

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3. Define rigid pavements. What are the types of rigid pavements?

Rigid pavements are those, which possess noteworthy flexural

strength or flexural rigidity. The stresses are not transferred from grain to

the lower layers as in the ease of flexible pavement layers. The rigid

pavements are made of Portland cement concrete either plan, reinforced or

pre-stressed concrete.

TYPES:

Jointed Plain Concrete Pavement (JPCP)

Jointed Reinforced Concrete Pavement (JRCP)

Continuous Reinforced Concrete Pavement (CRCP)

Pre-stressed Concrete Pavement (PCP)

4. What are the factors to be considered for selection of site for roads?

Type and purpose of road

Cross drainage works

Bridges

Railway crossing

Existing right of way

Public demand

Availability of material

Availability of labour

5. What is a tunnel? What are their uses?

A tunnel is an underground or underwater passageway, dug through

the surrounding soil/earth/rock and enclosed except for entrance and exit,

commonly at each end.

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USES:

Tunnels are made for highways and railway for regular traffic and

transportation of goods

Tube railways are made through tunnels

Diverting the river water through tunnels in the construction of dams

Pressure or hydropower tunnels are used in power generation

Tunnels are used for supply of drinking water, and oil or sewage

disposal or laying cables

Tunnels are made to extract minerals

Discharge tunnels to convey water from one point to another by

gravity

6. What are the advantages of tunneling?

Time saving and reduction in fuel

Avoid unwanted traffic congestion

Maintain a proper speed

Avoid tiredness of travel

Avoid unwanted accidents

To avoid deforestation and death of animal while crossing

To avoid land slide in hilly region

To avoid the long route around the mountain

To reduce the length of highway and railway and it may be

economical

7. What are the types of tunnel construction methods?

Classical method

Mechanical drilling / cutting

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Cut and cover method

Drill and blast method

Shields and Tunnel Boring Machines (TBM’s)

New Austrian Tunneling Method (NATM)

Immersed tunnels

Special methods (tunnel jacking)

8. Define cut and cover method.

Cut and cover is a simple method of construction for shallow tunnels

where a trench is excavated and roofed over with an overhead support

system strong enough to carry the load of what is to be built above the

tunnel.

9. What are the component parts of pipe jacking?

Thrust yoke

Skid base

Power packs

Intermediate jacking stations

10. What is meant by pipe jacking?

Pipe jacking is a method of installing a pipe under roadway, railway

or highways without using an open cut trench. The pipe jacking procedure

was a casing pipe of sheet or reinforced concrete (i.e.) jacked through the

soil.

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11. What are the techniques used in box / pipe jacking?

A technique used in box/pipe jacking requires the construction of just two

pits:

The thrust

Reception pits

Dimensions of the pits vary according to site conditions. Excavation

of soil can be by manual or mechanical means depending on the type of

machines used.

12. Give the applications of box jacking.

The applications of box jacking are,

Underground pipes

Ducks and culverts

13. Give the advantages of box / pipe jacking.

Environmentally friendly with minimal damage to the surface

Highly accurate and cost effective

Suitable for all kinds of profiles for a wide variety of soil conditions

Traffic congestion and additional pollution will not cause

Extremely suitable for all kinds of underground utility infrastructure.

14. List the disadvantages of box / pipe jacking.

Limited tunnel run resulting in more required shafts (approximately

every 1000ft)

Relatively straight alignment required (minimum radius of curvature

approximately 4000ft)

Difficulty in replacing damaged pipe.

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15. What are the types of cut and cover method?

Conventional method

Bottom – up method

Top – down method

Cast – in – place method

16. What is grouting?

Grouting is an engineering and art combined to fill up the voids or

cavities in rock or soil masses with fluid that will increase the overall

strength and impermeability of the mass.

17. Give the types of grouting.

Chemical

Cement

Jet grouting

18. Give the characteristics of grouting materials.

The characteristics of grouting materials are,

The grouting material has high permeability

No vibrations are used

Application requires no additional structures used

19. Explain about cement grouting.

In this method, cement grout which is a mixture of cement, sand and

water is used. The process consists of making a number of holes in ground

and then filling these holes by cement grout under pressure. This process is

continued till no grout is coming up through the hole.

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USES:

The grouting procedure can be used in stopping leakages from rock

It can also be used to fill the voids in soil so as to strengthen the soil

and to make the rock or soil water tight

20. Define TBM.

A tunnel boring machine (TBM), also known as a "mole", is a

machine used to excavate tunnels with a circular cross section through a

variety of soil and rock strata. They may also be used for micro tunneling.

They can bore through anything from hard rock to sand. Tunnel diameters

can range from a 1 meter to 19.25 meters to date.

21. List out the advantages of tunnel boring machines.

There is very less danger of fall outs in machine bored tunnels, since

adjacent or surrounding rocks are undistributed as no blasting is done.

Mucking is also safe and convenient, since muck is conveyed from the

face to the rear of the machine and is loaded automatically by means

to the rear of the machine and is loaded automatically by means of

belt conveyors.

Higher speed of excavation.

Reduction in the tunnel supports requirement.

Less manpower requirement.

22. Define shafts.

In civil engineering a shaft is an underground vertical or inclined

passageway. Shafts are constructed for a number of reasons including:

For the construction of a tunnel

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For ventilation of a tunnel or underground structure

As a drop shaft for a sewerage or water tunnel

For access to a tunnel or underground structure, also as an escape

route

23. Define tunnel lining. What are the types of tunnel lining?

The finishing touch given to the cross – section of the tunnel is known

as tunnel lining. The plain and reinforced concrete is generally used for the

lining.

TYPES:

Temporary ground support

Primary lining

Secondary lining

24. Mention the sequence of operations involved in during the tunnel

through rock.

Setting up and drilling

Loading the holes with explosives and firing

Ventilating and removing the dust resulted by explosion

Loading and hauling the muck

Removing ground water from the tunnel

Erection of supports for the roof and sides

Placing reinforcement

Placing the concrete lining

Curing and shuttering removal

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25. What are the objectives of ventilation system in a tunnel?

To provide fresh air for workers

To remove poisonous gases and fumes produced by explosion

To remove the dust caused by drilling, blasting, mucking and other

operations Performed in the tunnel.

26. Define mucking.

The operation of removal of excavated material in tunneling operation

is called mucking. Different methods of mucking are,

In small tunnels, hand carts or wheel barrows are used

Special power shovels are used in medium size tunnels which are with

a short boom and a dipper strikes.

Specially made mucking machines are equipped with dippers in large

tunnels.

Construction methods and equipments

Engineering

Transcript of Construction methods and equipments