ctb - 1-4

Construction Technology - B SEMESTER - 2

Task-1

Building Services

Water supply Sewerage and drainage facility Solid waste management Electricity supply Air-conditioning Fire protection Home pluming

Some essential points

Before details of water supply, sanitary fittings, and drainage of buildings are discussed individually, following are some of the common points which if taken care of whole planning of the building will result in economy of these services:-

All the wick’s bath rooms, lavatories and wash basins should be grouped on one side of the building.

Waco’s bath rooms, kitchen, etc should be located at least one external wall of the building.

General slope of terrace, chowk yards etc. Should be towards the side of the building on which drainage pipes have been laid. This facilititates easy drainage of water used for washing the rooms, chowks, verandahs, and also for the drainage of rain water.

Task 1:1

Water supply

Water supply pipe fitting provided in all the wicks, bath rooms wash basins, Kitchens etc. This system of water supply pipes is either fed from municipal water mains which run along the streets or fed through an over-head water storage tank. If water supply maintained for 24hours,there is no need of storing water, as water will available at taps for all the 24hours. In case water supply is only for some hours in a day, it is general practice to construct over-head storage tank. Overhead storage tanks are connected to municipal mains through pipes.

BTEC HND IN QUANTITY SURVEYING PAGE - 1


Water supply requirements for buildings

Water supply for residences:-

Requirements regarding water supply for residence should be assumed as 135 liters’ per head per day. But 135 liters’ per head per day, 45 liters’ per head per day is assumed as requirements for flushing and remaining for other domestic purposes.

Types of cold water supply system

The direct cold-water system

In this system the incoming water supply system from the service pipe is used to supply all cold-water outlets, including sanitary fittings. This system is economical on pipe work and requires only a small storage cistern, but it is not generally recommended for two reasons:

In the event of a supply failure there is no cold-water reserve, and, in times of peak demand on the whole supply network, noticeable pressure reductions occur.

Figure – 1 Direct cold-water system



The indirect cold-water system

In this system the incoming water rises directly to the cold-water storage cistern, with only one connection, for drinking-water purposes, being taken from, usually to the kitchen sink. This system increases the amount of pipe work required and the storage capacity of the cistern, but provides a small reserve cold-water supply and reduces the risk of contamination. Since all the other sanitary appliances are fed from the cistern, there is generally less pressure on the taps and valves, and therefore less wear.

Figure – 2 Indirect cold-water system

Hot water supply

Introduction

Hot water supply is required for hospitals, certain types of industries and lodging houses in hill stations. Water can be heated by gas, oil, electricity or solid fuel. A heater serving only one fitting is called a multipoint heater.



Electric water heaters

An electric water heater usually consists of a well insulated storage tank or cylinder with an electric immersion heater placed in it and controlled by a thermostat. The immersion heater usually consists of a metal rod which is heated by an electric element and around which water circulates. It is necessary to insulate the storage tank carefully and prevent circulation in any associated pipe work. Such stronger heaters are availably either as single point heaters directly over the sink or wash basin, or as multipoint heaters to proved the whole hot water system for the house or as cistern type heaters which are especially useful in blocks of flats.

Boiler systems

Direct system

In the direct system the boiler heats water, this rises in the flow pipe to the cylinder. This water is replaced by cold water from the bottom of the cylinder, passing down the return to the boiler. A circulation is thus set up which keeps the cylinder full of hot water. Hot water is drawn-off from the top of the cylinder by the distribution system to the fittings and is replaced by cold water from the main storage cistern in the roof, via the cold feed pipe connected to the bottom of the cylinder.

Indirect system

In these systems the hot water available at the fittings has not passed through the boiler, but instead, has been heated by a pipe coil inside the storage cylinder. This type of cylinder is known as a calorifier.the primary flow and return then becomes a closed circuit and has to have a separate cold feed from a separate tank. As this water is continuously reheated, any number of radiators can be put on this circuit. Provided the boiler is of sufficient capacity.

Water supply fitting

For water supply to a building always galvanized iron pipe is used. Size of the pipe depends upon factors like, head water, and population to be served etc. under normal conditions, individual residential buildings are provide 15mm diameter pipe. At the start of the building, the pipe should be taken up to plinth level. Using elbows and small lengths of vertical pipes. After this pipe line is maintained at plinth level and connection pipes are taken from to provide necessary water taps in bath rooms,w.c’s,kitchens, wash basins and sinks etc. For laying pipe line in a building following attachments are required:-



Sockets

They are required to lengthen the pipe line. Sockets have threads inside and they are tightened on the external threads made at the end of the pipes. Full length pipes have threads at their ends. But if pipe length has to be cut as per requirements, threads have to be engraved at the cut ends with the help of the threading.

Bends

They are also made of galvanized iron pipes. They can be used to give necessary bend to the pipe line. Now-a-days they are not in very common use.

Elbow It is made of galvanized iron. It is used to give 90degree turn to the pipe. In water supply pipe lines, elbows are mostly used. Use of bends has almost completely been criminated by elbows.

Bib – tap or water – tap

It is the water-tap which is provided at the end of the pipe connection. One end of it is tightened on the pipe and other end remains free to discharge water in atmosphere.

Stop – tap

It is a value which when inserted in a pipe line controls flow of water in the line. The standard size of a bib-tap or stop tap should be designated by the nominal bore of the pipe to which the tap is to be fitted. Bib – taps and stops – taps shall be of following sizes: 8mm,10mm,15mm,20mm,25mm,32mm,40mm,50mm.

Check nut or union

It is such an attachment by which two pipes which cannot be turned can be connected by sere wing one part of this value on one pipe and other end on the second pipe.

General requirements for the pipe work

The water supply mains may be classified into following categories

Mains Communication pipes Consumer pipes



Mains They are also known as municipal water mains. They consist of large-sized pipe carrying wholesome water for drinking and other used, for various localities of the city. These mains are laid along the roads leading to locality to be served by them.

Communication pipes It is part of the service pipe extending from the water main up to and including the stop – cock, which is under the control of the municipal author and not the consumer.

Consumer pipes The portion of service pipe used for supply of water and which is the property of the owner of the house is known as consumer pipe.

Water meters

Water meters are installed for all the connection given by the municipality. These are used to measure the amount of water that has flown through it. Occupants are charged according to the reading of the water meters.

Evaluation Here we can’t use direct system because our building has 4 stories therefore we used indirect system for our building. Here main incoming supply is directly connected to break tank and sump gets water from main incoming supply due to gravitation flow in main incoming line.

Then after water is pumped to over head storage tank from the sump by an external also capacity of pump should be approximately 15 minutes to pump out the total water from the sump, nowadays continuously running pump systems are popular in modest rise building.

Figure – 3- Elevation of building


3rd floor

2nd floor

1st floor

Ground floor

Over head tank


Conclusion

Sufficient knowledge has been gained on, different types of water supply systems and pipe works. What are the types of pipe lining method carried out in my site and it’s useful, different kinds of water supply methods also I was able to understand. In this task I have gained a lot of knowledge through my site visit.

Sanitary fittings

Various types of sanitary fittings are required to be fitted in the building. All these fitting should as far as possible is fitted against an external wall, so that the apartment in which they are situated can have free natural light and air. This aspect also facilitates easy drainage of connections. The floors of the rooms where any of the sanitary fittings should be provided with non absorbent floor. Such floors can be cement floors, clay tile floors, mosaic floors, and terrazzo floors.

Wash basin

Views of wash basin are shown in fig 5 and wash basin may be ordinary or pedestal type. The wash basin should be so fixed that the height from the floor to the top of the rim of the basin is 78.5 mm. wash basins are used for washing hands, tooth brushing, face washing,etc.

Sinks

They are rectangular basins made from glazed earthen ware or stone-ware. They have flat bottom and all their internal angles are made round for easy cleaning. They are used for washing in kitchen or laboratories. They should be fixed in such a way that height of the top of the sink from floor is 900mm.

Water closet

It is used receive human excreta directly from person using it. The appliance is connected to the soil pipe by means of the trap. The water closets (w.c) may be Indian type i.e.squating type and wash down pedestal or European type. Both these w.cs have an arrangement of flushing the discharged excreta by the persons with the help of water.

Urinals

They are used to discharge urine. Contents of urinals are collected and discharged into the soil pipe through floor. Urinals are generally provided with automatic flushing cisterns which operate at intervals of 10 to 15 miniutes.urianals should be the designed to allow a minimum clear width of 60 cm between partitions.


Foul water Soil water

Figure - 4

Foul water

To septic drainage To septic tank

Soil water

Ventilation pipe

Figure-5


Task- 1:2

Drainage and sewerage disposal system

In our building, each apartment has one wash basin & shower in bathroom sewerage disposal system has following methods:-

1) One stack system 2) One pipe system3) Two pipe system

One stack system

In this system, all waste water was collected by a single down word pipe

One pipe system

All foul water was collected by a single pipe and soil water was collected by another single pipes but this pipes not going to down word, and this pipes was connected with a main down word pipes

Two pipe system

All soil water and foul water was collected by separate pipes



Drainage of house

Drainage of locality can be divided into two heads public and private. Public drainage includes facilities provided municipalities or corporations. Under the category of drainage municipal sewers are laid along the road and are properly maintained in a well organized way houses and other buildings. Constructed along both the sides of the all road, lay their own sewer lines insides their premises. These server lines collect sewage and the waste water from kitchens baths ,W.c’s urinals wash basins etc.fitted in the building and convey it to the municipals or corporation sewer running in front the line of houses along the road system of sewer lines or drains laid in the premises of an individual private or public building is called the house drainage.

Principles of house drainage

Design and the construction of house drainage system is controlled by the following general principles

1) House sewers or drainage should be laid as far as possible by side of the building rather than below the building.

2) The size of the drain should be adequate .this will avoid flooding of the drains when handling the maximum discharge from the house.

3) The drain should be laid at such as level that the lowest level of the building may drain in it.

4) Drains should be laid at proper gradient so that self cleaning velocity is developed in them.

5) Drain should be non –absorbent type, laid on good foundation and protected against external loads.

6) As far as possible drains should be laid in straight lines between successive inspection chambers. All sharp bends and junctions should be avoided except through chambers or manholes.

7) The entire system should be properly ventilated from the starting point to the final point of disposal.

8) Ample means for inspection and access should be provided.

9) The house drain not be connected to the public sewer directly but through an intercepting trap .this provision prevents the entry of foul gases. From the public sewer into the house.



10) All the joints of the sewers should be made water-tight and should be properly tested before putting the drainage.

11) The house drainage should have enough number of traps at suitable points for its proper and efficient working.

12) The house drain be connected to the public sewer only the level of public sewer the public sewer is lower than the level of the house sewer at that point .if this condition is not properly appreciated, the flow in reverse director (from public sewer to house drainage )may take place.

13) Drainage system should be such that sewage is immediately conveyed to the public sewer

14) Possibilities of formation of air locks siphon age under deposits etc.should be carefully studied and measures adopted in design to avoid them.

15) Rain water from roofs and chows is allowed to be drained along with waste water through the house drains. But water from lawns and other open spaces is allowed to flow out freely and drained through public sewers. This water enters the public sewer through the catch basins and inlets provided in the kern drain in the road along which public sewer line runs.

Evaluation

We must joint ventilation pipe with sewerage pipe because all bad gas will go to atoms put through ventilation pipe.

Normally we used PVC pipes for sewerage. In this sewerage we used two pipe system because near the building has a canal therefore we can dispose the foul water to the canal so two pipe system better than other two system.

Conclusion

Lot of knowledge has been gained by, different types of Drainage and sewerage disposal systems and it’s construction methods. In this task I have gained a lot of knowledge through my site visit.



Task-1:4

Solid waste management

Many types wastes are in the apartment we want disposal are used in cities they are

1 Waste generation 2 Onsite storage3 Collection 4 Disposal

In our building has apartments and shops therefore is suitable for our case

Disposal

Disposal is the ultimate stage of all solid waste there are three different methods

1 Sanitary land filling 2 Incineration 3 Composting

Solid waste disposal system

Solid wastes are all waste (arising from human and animal activities) that are normally solid and that are discarded as useless or unwanted. In urban area waste is heterogeneous. In rural area waste is homogeneous.

On site handling

Activities associated with the handling of solid wastes until they are placed in the containers. Residents should place their solid waste into storage containers at different locations.

High Rise Building

Wastes are picked by the maintenance people from various floors and taken to the basement. Wastes are taken to the basement by residents. Waste are usually bagged are placed by tenants in specially designed chutes. Chutes for using apartment buildings are available in diameters from 12 inch-36 inch most common size is 24 inch diameter.

Disposal Principal Methods

Sanitary land fillings: - sanitary land fill is a placed where wastes are buried in a manner that minimizes the impact on the environment. Dump the waste. Spread and compacted inlayers 10’

– 15’ deep. Cover the waste with 6” - 12” soil layer at the end of each day.



Advantages

Simple to construct and operate. Low in cost. Quick.

Problems

Availability of land. Soil and water condition & Distance from waste sources.

Septic tank

Septic tank installations can vary from being little better than a leaky cesspool, to providing an unobtrusive and efficient means of domestic sewage disposal. In a properly designed and constructed septic tank installation, the natural bacteriological processes of decomposition take place under controlled conditions to produce a clean and inoffensive effluent.

Septic is device to deal with the sewage from water to closets in areas where municipal sewerage system has not been installed .septic tank may be constructed by an individual or by an group of families .septic tank is a water tight single storied underground tank in which sewage is retained sufficiently long to permit sedimentation solids and partial degustation of settled sludgy by anaerobic bacterial action.

Design septic tank

The size of a septic tank is governed by the following factors

1) The floor area of the grit chamber has to be adequate to reduce the velocity of flow and permit sedimentation.

2) Capacity should be adequate to provide detention period varying from 12 hours to 3 days 24 hours period is usually considered satisfactory.

3) The depth below part ion wall opening should be sufficient to permit sludge. Accumulation for predetermined period. A minimum area 0.07m per user in grit chamber and minimum volumetric content of grit chamber and minimum volumetric content of the grit chamber 0.02m per user are required.

4) Septic tank should have minimum width of 0.75 m and minimum depth of the one metric below water level .it should be of minimum 1 m capacity. Length of the tank should be 2 to 4 times the width.

5) Every septic tank should be provided with ventilating pipe of at least 5cm diameter.



Factors:-

1) Sufficing storage capacity.2) Diameter of pipes.3) No blockage.4) Ventilation.5) Liquid depth. Normally 5 feet.6) Length and width. Normally 4-5 feet

When we select the land for septic tank construction. We must consider the following details they are

1) Water table level for proposed land.2) Population.3) Cost.

The under ground tank

The septic tank itself is only the first part of the purification process. It is a watertight underground chamber designed to retain sewage for at least twenty four hours, to allow anaerobic bacteria to carry out the initial stages of decomposition.

Most existing septic tanks are rectangular in plan, about three times as long as they are wide, and between 5ft and 6ft deep. The building regulations require new septic tanks to have a capacity of at least 2.7 cubic metres (600gal) but, as with cesspools, most septic-tank installations were provided long before the advent of the building regulations. Dip-pipes are provided at both inlet and outlet of the septic tank. These ensure that sewage enters and effluent flows away from beneath the surface of the liquid in the tank, leaving the scum that will form on the surface undisturbed. Flow through the tank should take place as slowly as possible. The outlet is therefore only a few inches lower than the inlet.

Providing a septic tank system

Most septic tank installations are built in situ of bricks on a concrete base. There is

however sectional precast concrete and one piece glass reinforced plastic, septic tanks on the

market. Always consult the environmental health officer of the local district council before

incurring any expends very much upon local conditions. An installation that might be

perfectly acceptable for a remote Mooreland cottage could present a serious danger to health

if it were provided on the outskirts of a populous village.



Maintaining a septic tank system

Septic tank systems are self-activating and will usually function satisfactorily for years

with minimal attention. The tank will need to be dislodged, by the council’s or private

contractor’s cesspool emptier, very occasionally. Six-monthly dislodging has been

recommended, but most septic tank owners would agree that six months is a ridiculously

short period. Provided that the system is otherwise satisfactorily installed, dislodging on

alternate years should be sufficient.

If we have septic tank drainage never forget that septic action is bacterial action.

Don’t overdo the use of disinfectants when cleaning the drains, for disinfectants are quite

incapable of distinguishing between benign and harmful bacteria. Don’t allow the brine wash

from a water softener to flow into the septic tank. Salt has a strong antiseptic action.

Septic tank and soakage pit.

Households not served by public sewers usually depend on a septic system to dispose of

wastewater. There are many different types of septic systems designed to fit a wide range of

soil and site conditions. These include mound systems, sand filter systems and pressure

distribution systems.

Soakage pit.

A main purpose of soakage pit is filter water and allows the ground it has granular soil partials and more water.

Evaluation

In this task analysis different types of Solid waste disposal systems and principals of Disposal methods and it’s advantages.

Conclusion

Sufficient information has been gained on different types of Solid waste disposal systems, Septic tank, Maintaining a septic tank system and its Principals.



Task – 1:4

Electrical Work

A new Four-storey residential building to international quality and the electrical work forms a major portion of the project.

In building construction a considerable portion of work belongs to the area of electrical engineering. This work goes hand in hand with the civil work and a basic understanding would definitely facilitate the smooth progress of the project as a whole.

Most of the services and equipment in a site requires the use of electricity and the means of arrangements involved in this regard has to be arranged in managing a site.

The electricity is a service daily consumed by us and a proper understanding would benefit a lot.

Basic Features and Details of the System

According to the design the main power supply is from the CEB supply lines. An additional power plant consisting of three 100kv standby generators will also be installed for any emergency supply. All the houses are provided with three phase electricity (30A / 230A/ 50 MHz) and are air conditioned with individual A/C units fixed inside the house. The houses are sold with fully furnished condition and with the intention of minimizing subsequent work the outlet points are provided in all the possible points demanding electricity. Also the supply lines are capable of supplying some additional power requirements if the customer decides to refurbish.

Typical supply points of a house

Power supply points

Washing Machine 15A Dish Washer15A Garbage Grinder 15A Cooker 15A Refrigerator 15A Shaver Socket 5A Geyzer15A Air Conditioners 15A Fans 5A



Wires used in work

All the wires used in the site are from ALUCOP CABLES. The properties are as follows

The sizes of the cable and their applications available in the market are

Table – 1 cable details

Cable diameter (mm) Application

1 Lighting

2.5 Earth wire, 5A power lines,

4 Air conditioner lines

6 Cooker lines

The wires are available in coils of 30m length.

Standard colors used in wiring

Live wire - Red

Neutral wire - Black

Earth wire – Green

Conduits fittings used in work

The UPVC conduits and fittings from ANTON are used in the work. The advantages of using these are

Single conductor wiring eliminating magnetic effects

Multi conductor wiring

Retardant to fire and does not support combustion

Non-corrosive, Light and tough

The properties of a pipe are marked on the surface of it at regular intervals (1m) in a standard

method similar to pipes used in plumbing.



Commonly conduit sizes and length available in the market

Table – 2 pipe diameter

Procedure of Wiring

As in any large construction project in this project also the circuits consists of a set of lines going through the slab and reaching down the outlet points through the brick walls or concrete walls. Initially the conduits are laid with junction boxes wherever necessary. The laying of conduits is done prior to the concreting. To ensure that the junction boxes could be opened properly we fix a wire nail to the bottom of the box with it’s edge pointing outward and place it on a regiform piece which is the n placed on the form board. After removing the form board we open the box by pulling down the bottom with the nail previously fixed.

By inserting a flexible rod from a junction point and checking the point from which it comes back we can check the correctness of the conducting arrangement. Thereafter the wires are drawn inside the conduits with or without the aid of a rod.

Once the brickwork is completed the conduits in bricks is fixed. After the plastering is done those conduits would be wired and the sun boxes are fixed to walls by nailing. It is important to do a setting out in fixing sun boxes.

In certain conduits several lines would be drawn. In order to prevent any confusion the electricians use a coding method by which they would mark the details of that wire by making temporary marks on it.

Testing the Wiring System

Once the wiring of a house is completed the system has to be tested for its correctness and the capacity. Two basic tests are done in our site in this regard.


Pipe Diameter Length Available

25mm – 3/4// 13/

32mm – 1// 13/

40mm – 1 1/4 // 13/

50mm – 1 1/2 // 13/


Insulation Test

When wires are drawn in the conduits the process of drawing may result in wires being elongated. If the amount of elongation is too much it affects the capacity of the wire to transmit electricity. With the aid of a special meter all the lines are checked with taking the insulation values as the testing parameter. If any of the lines fails this test the lines would be redrawn.

Power Test

This is the most important test for electrical work. This is used to check the accuracy of wiring as well as the capacity of the outlets. In this test the lines are supplied with the rated power and the performance is checked. Generally, a house is tested as one unit at once.

Evaluation

In this task describes Power supply points, Conduits fittings used in work, Commonly conduit sizes, Procedure of Wiring, Testing the Wiring System, Insulation Test, Power Test and it’s connecting methods.

Conclusion

I was gained a lot of knowledge for electrical work and it’s Procedure of Wiring.

Air-conditioning

Air-conditioning today has acquired great importance. Modern air conditioning consists of self-contained units with compressor, evaporation fan and cooling condenser. Such unit (room air conditioner) is suitable for a single room having limited occupancy, such as bed rooms, office rooms and other places where demand for air conditioning is nominal. These should be installed near a source of out side air to prevent heat injection.



Task – 1:5

Fire protection

Classification of buildings

Buildings can be divided into different groups based on their degree of fire resistance and occupancy

Degree of fire-resistance

The duration for which a building and its structural components defy the fire effects and perform satisfactorily is a measure of the degree of fire-resistance of the building. The fire-resistance of a building is expressed in hours against a certain intensity of fire. The buildings can be classified as below.

Type of duration fireConstruction (Hr) intensity

1 4 540 to 1095

2 3 540 to 1057

3 2 540 to 1010

4 1 540 to 925

Occupancy

Building can be divided according to occupancy as follows

Group A: Residential: buildings which provide sleeping accommodation except institutional buildings Eg: loading houses, family dwellings, dormitories, apartment houses, hotels etc.

Group b: Educational: buildings used for schools, colleges or day-care purposes, except assembly buildings.

Group c: Institutional buildings used for purpose like medical treatment of persons suffering from physical or mental illness. Care of infants, convalescents or aged persons, care of persons under penal or correctional detention where the liberty of the inmates is restricted



Group D:

Buildings where groups of people congregate for amusement, recreation, social, religious or similar purpose. Eg : theatres, auditoria, museums, places of worship, passenger stations etc.

Group E:

Commercial; buildings used for transaction of business other than mercantile buildings for keeping of accounts and records, e.g. News stands, lunch counters serving less then 100 persons, beauty parlours,ect.

Group F: Mercantile: Buildings used as shops, stores, markets.

Group g: Industrial: Buildings, in which products are fabricated, assembled and tested e.g. Assembly plants, dry cleaning plants, pumping stations, dairies, saw mills etc.

Group H: Storage: Buildings used for storage of goods or merchandise, e.g. warehouse, god owns, cold storages, transit sheds, garages, etc.

Fire zones

The city area is demarcated into distinct zones based on fire hazard inherent in the buildings and structures according to occupancy. The fire zones may be designated as:

Fire zones No 1: Residential (group A) educational (group b), institutional (group C), small business (group E) and retail mercantile (group f) buildings.

Fire Zone No 2: Business (group E), industrial buildings (group G), except high hazard industrial buildings.

Fire zone No 3:

Areas having high hazard industrial buildings, storage buildings (group H) and buildings hazardous uses (group J)



Exposure

The site planning of buildings and space around buildings reduces the possibility of fire spreading from one building to another. Proximity of buildings causes fire to spread easily by heat radiation.

The spread of fire by heat radiation can be tackled by providing.

a) An external masonry wall constructed with fire - resistant materials, light-weight concrete, etc. between sources of fire and combustible materials.

b) Sufficient space between buildings so that ignition by heat radiation cannot take place.

When the ability of the roof of a building to resist fire penetration is found to be low, the space between buildings should be increased. I.e. the lower the résistance, the further away must be the buildings.

Fire - spread

a) Large buildings should be dividing horizontally and vertically into compartments by fire-resistant floors and walls. Instead of a single large room, it will be safe to provide a number of smaller-size rooms.

b) In the case of industrial buildings, high-risk areas should be isolated from others.

c) Although the use of fire-resistant doors and windows may be advocated, it should be borne in mind that shutters do not provide appreciable resistance to radiated heat. A rule of thumb limited is to the area of openings to three-fourths the area of wall.

d) Preference should be given to the use of materials which are bad conductors of heat and have good fire-resisting qualities.



Task- 1:6

Home pluming

In some houses the bathroom cold taps are also supplied direct from the main and the water supply to them is cut off in exactly the same way. It is more likely though that bathroom cold taps are supplied from a main cold water storage cistern situated in the roof space.

There may be gate valves, which you can turn to cut off the water supply to these taps, in the distribution pipes leading from the storage cistern. Usually though, you’ll find that you have to drain the cistern. The water Byelaws now require that a mini stop cock must be fitted as closely as practicable to the inlet of every ball valve.

Number of appliances.

Temporary accommodation.

Water closet 1

Wash basin 1

Bath 1(optional)

Sink 1(cleaning purpose)

Super market.

This is including in public group.

Water closet 1; 50(male)

Urinals 1; 50(male)

Water closet 1; 40(female)

Wash basin also should be provided at the some scale as water closet.



Task-2

ROAD CONSTRUCTION

Introduction of road construction

A road structure is typically composed of several layers of material. Each layer receives the loads from the above layer, spreads them out, and then passes on these loads to the next layer below. A road is a hard surface made on an embankment for easy transport of goods and passengers by vehicles. A good road should have following characteristics:-

Straight as much as possible

Short as much as possible

Easy curves, Low gradients

Strong foundation

Good sight distance

Classification of roads

The classification of the road network is essential requirement required to improve the

road and have suitable maintenance. At present the road network in Sri Lanka has been

classified into five classes, according to their sizes, usefulness, traffic capacity and the

condition of the road. These major categories are A, B, C, D and E.

A-class road

These are main arteries or long distance routes for moving traffic between different

parts of the country, normally the major cities and towns. These are called trunk roads. Trunk

Roads connect provincial cities and major parts of the country.

B-class roads

These roads from the next level of the hierarchy and distribute traffic between residential areas, industrial areas, town centres and feed the A-class roads. Also these roads connect the administrative districts to the provincial cities.

C-class roads

These are main collectors and distributors within any zone of area that feed the above A-class and B-class Roads. Also roads except A and B class roads that carry heavy traffic volume fall under this class.



D-class and E-class roads

These types of roads are known as minor roads. These are local roads that provide access to settlements and villages. Provincial councils, local government organization, estates and other organization own these roads.

At present the road network in Sri Lanka has been classified into five classes, according to their uses of materials.

1. Earth Road2. Gravel Road3. Metal and tarred road4. Metal and tarred road with seal coat

SBST – single Bituminous surfacing treatment DBST – Double Bituminous surfacing treatment

5. Metal and tarred road with Asphalt surfacing

Task – 2:1

Factors which control the selection of alignment

1. Volume and type of traffic expected to use the road.

Before fixing any alignment traffic and economic studies should be carried out. These studies give an idea about goods and passengers traffic, expected on the proposed road. If the traffic predominantly slows moving the alignment may be of winding nature joining all the villages. Such roads should have easy gradients but may have sharp curves. But if traffic comprises mostly of fast moving type vehicles proposed alignment should be as straight as possible having easy curves but the gradient may be a bit more than that given in bullock cart roads.

2. Geological condition.

Geological conditions of the area should be thoroughly investigated. The sole purpose of this investigation is to locate road alignment on good soil and also to have good foundation conditions for proposed cross drainage works. Good soil will not easily promote subsidence of road and will not easily slide or slip at the slopes. Marshy and water logged lands should be avoided as it will be difficult to construct and maintain a road in such places. Cuttings and fillings in rocky soils are also not good. Cuttings in rocks very costly and fillings are liable to slip.

3. Canal, river or railway crossings.

A road crossing canal, river, or railway line, at right angles, is considered best. If they happen to meet at other than right angles, road alignment may be deviated so as to cross these features as right angles. Bridge site on river or stream should be selected considering the structural and foundation requirements also.



4. Floods in the area

Road formation should be fixed at least 60 cm above the high flood level occurring in

the area. Floods normally undermine the road embankment and should be protected

against scouring. In snow fall areas cutting should be avoided as it has to be lifted up

while clearing the road from snow. In cold climate areas, road alignment should run on

the side of the hill opposite to the wind direction but on the side of the direct sun.

5. Places of availability of construction materials and labour

Road alignment should pass through such places where labour and good

construction materials are easily available. This aspect helps a great deal during

construction and later on the maintenance of the road.

6. Existing right of way

If the roads are aligned along the land earmarked for road construction in general

planning it will reduce the cost of land acquisition. But if other factors are affected by

aligning road along existing right of way road may be deviated from it to suit to the most

suitable conditions.

Construction categories

Road construction is divided into three categories:-

1. New constructions2. Re-constructions3. Stage-constructions

New constructions The new construction is meaning that the road is conducting from initial stage to connect two stations.

Re-constructions Any improvements or constructions works done in already made road is called re-construction.

Stage-constructions The construction works are carried out in stages. These stages are drain, culvert and retaining wall construction, preparing sub base and base and asphalt construction.


Carriageway

0.8 m 0.8 m2 m 2 m3.7 m 3.7 m

0.6 m

0.15 m

3 %Shoulder

FootpathDrain


Road cross section

Carriageway

The carriageway is the surface of the road on which the vehicles are expected to run. Carriageways can be single lane, two lanes, four lanes or multi lanes. A traffic lane is defined for the use of a single line of traffic demarcated by lane marking.

Shoulder

The shoulder width is measured from edge of the carriageway to the edge of the usable formation free from obstructions. It is used for pedestrians, pedal cyclists and vehicles for standing. The width of shoulder is 2 m.

Drains

Drains are provided for the efficient discharge of storm water that falls into them from the road surface. The minimum width of drains should be 0.6 m; the cross section may be rectangular or trapezoidal.

Centre median

For four lanes or multilane roads, medians are required to drive the carriageway to avoid conflicts of opposing traffic. They also provide refuge for pedestrians crossing the road. For safety reasons two-way multilane roads should always have medians.

Right of way

Right of way is the total land area used for the road including the reservation for utility services and any widening in the future.

Cross fall The purpose of the cross fall is to drain the road surface. The cross fall of the carriageway is 3% and footpath is 2 %.


Figure – 6 Cross section of the road

PROPOSED BUILDING

Bridge

River

Road


Task – 2:2

Road design

We need to design a road we should consider following things 1. Design of road alignment 2. Design of road element3. Design of road drainage4. Traffic design

Figure – 7 construction details

Design of road alignment include dimensions

Plan a view

Plan a view indicate shortest path, avoid drives, ponds, lakes, marshy lands, stream and traditional buildings if is rives, lakes, stream and ponds, we have to put proper bridge moreover if it is marshy lands, it must be consolidate.

Elevation

This is most importation to design road these elevation consist cut and fill. Cut and fill is nearly equal the construction cost very low than other cases.

Cross section This Analysis number of lanes, width of lanes, number of cycle lanes, shoulder width, drainage of road.



Road surface elements

Road sub grade Road sub base construction Aggregate base Road pavement Road drains Road signals Binder course Wearing course

Road components

Wearing Course 4

Base courses 3

Sub base 2

Sub grade 1

Figure – 8 Road components

Sub grade

This is probably a soil foundation, which is strong enough to bear loads. In other word the

final shape of the ground after compaction. A good sub grade must be dry, stable & of

uniform bearing power.

Sub grade material

Materials used for selected sub grade shall be naturally occurring soils or gravels and

shall not include highly plastic clays, silts, peat or other organic soils or any soil that is

contaminated with topsoil, vegetable or other deleterious matter.



Failure of sub grade

The failure of sub grade may be attributed due to the following two causes.

Inadequate stability Excessive stress application

The inadequate stability of the sub grade may be attributed due to the following factors,

Weakness of the soil itself. Highly moisture in the sub grade. Lower compaction of the sub grade.

Sub base

It is the lowest layer in the pavement. The main function of the sub base is to assist the road base in spreading the vehicle load to the sub grade. The sub-base course is between the base course and the sub-grade. It functions primarily as structural support. The sub-base generally consists of lower quality materials than the base course but better than the sub-grade soils. A sub-base course is not always needed or used. For example, a pavement constructed over a high quality, stiff sub-grade may not need the additional features offered by a sub-base course so it may be omitted from design. However, a pavement constructed over a low quality soil such as swelling clay may require the additional load distribution characteristic that a sub-base course can offer.

Sub base material

The materials used for sub base shall be naturally occurring or blended gravels and sands or mixtures there have and shall not include highly plastic clays, peat or other organic soils or any soil that is contaminated with top soil vegetable and other deleterious matter. The CBR shall not be less than 30% and cases of bases not be less than 80%.

Failure of sub base

The sub base will failure due to the following reasons

Material loss Lack of lateral support for the base course Inadequate strength or stability Inadequate thickness of wearing course Improper mix proportion Inadequate thickness of the sub base Poor quality control during construction period



Sub base laying procedure

The sub base construction done above the sub grade of the road.

The minimum thickness of sub base should be 225mm and maximum thickness is

depend on the final level of the proposed road.

The sub base construction started after drainage works have been completed.

The bituminous surface was removed by scarifying.

The exposed surface shall be compacted prior to laying of the sub base.

The sub base material was spread in layers and each layers should be compact after

225mm thickness laid.

Before compaction have to check the dip measurement if carriageway width was

4.5m,the slope should be 3%.

Finally applied water and compaction done with 12ton vibrating rollers. The

maximum speed of this roller is 30Km/hr.

The sub base should be compacted to a density is not less than 98% of the maximum

dry density as determined by the compaction test.

Aggregate base course

The Aggregate Base Course (ABC) layer is a main load-spreading layer. The thickness of the ABC layer is 150 mm according to the design drawing. The ABC material is mixing of aggregate and quarry dust. The graded crushed rock aggregate with nominal size 37.5 mm is used for this ABC layer.

The degree of compaction of ABC layer should be above 98 % of Maximum dry density otherwise the compaction is failure.

Figure – 9 Structure of ABC layerPavements

The main function of a pavement of a road is to distribute the concentrated loads so that the supporting capacity of the sub-grade soil is not exceeded. With this purpose in view, the


Level at edge of the carriage way

Road center level

0.5m off set

Level at edge of the shoulder

ABC layer


road-structure has been composed of a number of layers properly treated and compacted and placed one above the other.

Pavement materials

1. 100mm(4”)metal

2. 50mm(2”)metal

3. 19mm choker stone

4. Sand and gravels

5. Tar

There are two type of pavement design:-

1. Flexible pavement design

2. Rigid pavement design

Flexible pavement design

The soil foundation formed after either completion of excavation works for a cutting

or the formation of an embankment is called the “sub grade”. Usually the surface of the sub

grade is referred to as the ‘formation level’. The flexible pavement is then built up in layers

as follows.

Surface courses

The surface courses is usually constructed to produce a comfortable ride for traffic,

and should ideally be hard wearing, resistant to weather attack, and display good properties

with respect to skidding. In addition adequate water proofing to the lower layers is essential

and can be obtained by careful selection of surface material.

On highly used roads it is common practice to separate the surface course into two layers wearing and base layers. This method of construction facilitates maintenance, repairs and, in particular, replacement of the wearing layers. However, for minor roads the two are usually combined. The surface courses are generally made from tar or bitumen bound aggregate.

Road base



The road base acts to distribute the wheel loads through to the sub grade and therefore performs a most important function in the design of the pavement. High quality materials are required, such as hardcore, graded granular materials laid either wet or dry, cement or bituminous stabilized soil or gravel, or lean mix concrete. Depending upon the material, the method of lying can either be carried out using a paving machine or by simple spreading with bulldozers or graders combined with adequate compacting.

Sub base

This is an extension of the road base and will be required depending upon the quality of the sub grade and loading on the pavement. Compacted granular materials to aid drainage are common and may be of lesser quality than those used in the road base. Nevertheless the sub base must be than the sub grade.

Rigid pavement design

Surface slab

This forms a structural plate and is formed from high quality strong concrete, sometimes reinforced with steel bars or mesh. Common practice often allows for expansion and contraction by incorporating joints at intervals passing through the slab. Lying is generally carried out with a paving machine.

Sub base

When the sub grade can’t provide uniform support to the slab because of the effects of frost action, poor drainage, swell and shrinkage, bad practice during earth moving operations, construction traffic, etc.., a sub base is usually interposed between these two surfaces.

The sub base may be formed of granular materials or a week mix concrete with the top surface sealed with a thin bituminized layer to prevent water absorption from the concrete layer. Lying can be carried out form a pavers or simply by spreading, grading and rolling with earthmoving equipment.

Sub grade

The sub grade forms the natural foundation to the pavement and is the result of either excavation works or the forming of an embankment. Thus it is important that adequate compaction takes place before constructing the other layer.



Maximum compaction is achieved at some optimum water content for the particular soil. This value may determine in the laboratory, with the subsequent standard of compaction to be achieved on site specified at some proportion of this value.

The design thickness of the pavement may be determined, by several methods, for example California Bearing Ratio (CBR) of the soil. The laboratory test uses a disturbed sample which is reformed and compacted in a standard mould to a state anticipated at the construction site. A penetration load test is then performed and the CBR value obtained. A similar procedure could be carried out in situ on the actual sub grade.

Drains

Drains are provided for the efficient discharge of storm water that falls into them from the road surface. The minimum width of drains should be 0.6 m; the cross section may be rectangular or trapezoidal.

Drains materials

1. Plastic tank2. PVC pipe3. Kerbs4. Concrete pipe5. G.I pipe6. Gullies

Binder course

This is the thick layer of asphalt concrete, it has enough strength bear the load without any cracks, also it used to correct the super elevation and cross fall.

Wearing course

This is the top most layer of the flexible pavement laid on the base course. It varies

from 25mm-75mm in thickness& is generally made up of bituminous mixtures. This is

provide a rough, dust free clean surface and to prevent the entering of water in to the base.

Figure – 10 A longitudinal section of a road


Wearing course Binder course

Base


Other road accessories (Road signals)

Traffic control

By using traffic control devices can ensure the safety of road users and also to

streamline the flow of traffic and minimize delays to road users. When performed the road

project, the specifications of the traffic control devices and regulations are given in the

government gazette No. 444/18 dated 13/03/1987titled as “Motor Traffic (signs) Regulations.

- 1987

Since selected project road is used when construction take place several traffic control

devices had used. Base on the available information a traffic control plan had been prepared

and such plan indicates the signs and devices needed at the site, however before traffic

arrangement all the plans are recommended by site engineer. To provide reliable traffic

control below factors must be taking in to account.

All road works even minor maintenance measures should be planned well in advance as

soon as possible.

Uniform and continuous signs should provide all over the road work network.

All traffic control devises should be kept in good condition and checked regularly,

especially in dark.

The behavior of workmen should always be good in order to gain respect and

confidence of the drivers.

Always there should be responsible person to give orders to control the traffic.

As soon as a road work is finished the traffic control devices should be removed.

Below tactics used to control the traffic when construct the selected project.

Table – 3 traffic signals

TRAFFIC SIGN INSTRUCTION ADDITIONAL DETAILS

Road work ahead If the length of the road works is

morethan 1000m then the length

should be indicated on an

additional panel.



Road narrows on both side ahead Used only if the width of the

carriageway is decreased

substantially or if the decrease

means vehicles can’t pass each

other.

Road humps ahead Use if there any humps had been

deliberately formed to reduce

vehicle speed.

Road narrows on the left side

Ahead

Used only if the width of the




other.

Road narrows on the right side

ahead

Used only if the width of the




other.



Slippery road ahead Where road section becomes

slippery and hazardous as places

where newly laid asphalt concrete

surfaces.

As well as where trucks move

to the roadside on to the

carriage way.

Loose gravel ahead Where road section with loose

aggregate/ gravel on the carriage

way, in places where loose chips

had laid as surface treatment.

Road closed for all vehicles Used where road work area is

closed for all vehicles but the

closure made in such a way that

people along the closed road can

reach their homes.

If the closure occurs between two

intersections the sign should be

erected at each of the intersection

and provided the distance from

work place to sign


30km.p.h.


Speed limit The numerical value given in the

sign is for illustrative purposes

and actual numerical value should

be inserted according to the

restriction to be imposed.

Pass this side – Right side Where all vehicular traffic shall

pass on the left side.

Pass this side – Left side Where all vehicular traffic shall

pass on the left side.

Priority for on – coming traffic Use to notify the motorists,

entering a section of a road area

or a bridge where priority shall be

given to on- coming vehicular

traffic.

Priority over on – coming traffic Use to notify the motorists,

entering a section of a road area

or a bridge where priority shall be

given over on- coming vehicular

traffic.



Text Signs

Apart from the traffic signs, other messages could also be conveyed to the motorists by providing rectangular sign boards with messages in words. The background of the board is yellow and massage given in all three languages and standard letter size should be minimum 100 mm (4 inches)

Barricade board

L

Figure – 11 Barricade board

These are used to demarcate the section of roadway closed for traffic when road works

are in progress. They are rectangular in shape as shown made of 40 mm to 50 mm thick

wooden planks or of steel, aluminums or plastic material with supported on movable stands.

There boards should be placed at the ends of the obstructions as well as along the obstruction.

Direction Board

L

B

Figure – 12 Direction board

Directions board may be used temporarily at road works to indicate the direction of road deviation.

The following table indicates the standard sizes for barricade and direction board.


S


Table - 4 standard sizes for barricade and direction board

Type L B S

Normal size 900 300 150

Large size 1800 400 200

Side Obstacle Markers

Side obstacle markers may be used to mark points where the carriage way narrows in a way that

is not clearly visible to the drivers. The side obstacles markers shall always be erected so that the bars

are sloping down towards the carriageway.

Traffic Cones

1/4 or 1/3 of height

450 min.

750 max.

225-375 mm dia

Figure – 13- traffic cones

Traffic cones are temporarily provided on the carriage way during road works can be used to divert traffic around road works or trenching and are generally placed around the obstruction or parallel to the centerline of road. These are made of rubber or suitable plastic material and the base of the corn shall be more weighted so not topple over due to minor impacts of moving vehicles. By using extra weight which will not damage or injury vehicles and humans in case of fallen of cone. Sand bags or rubber rings are ideal for extra weight.

The spacing between the traffic cones vary according to the speeds of motor vehicles. In our selected project average cone spacing is 9 m on the straight section parallel to the centre line of the road and 1.2 m spacing on the tapering section. A tapering angle of 30 0 to 45 0 also used.



Barricade Tape

Figure – 14 Barricade Tape

These are also used to improve the visibility of a road closure or an obstruction. However these should not replace barricade boards’ r other physical devices for reasons that the tape can easily be removed and tape is not reflective. When use the tape have to use supplement cone as indicator.

Lighting Devices

Lighting devices (Yellow / Amber coloured Battery operated Flashers or Lanterns or Electric Lamps) may be used to provide adequate lighting in the night or even the visibility is reduced due to rain and frog since site is placed at up- country.

When providing the lighting there should be an adequate distance from the danger to take actions to overcome the situation. But it is not possible to fix flashers and lanterns to the cones or other similar devices, which could be hazardous if the vehicle knocks it.

Lanterns

The light from lantern is visible from all directions and should therefore preferable to be used when there is mixed traffic from several directions. But lantern light hasn’t reflection quality and then it reduce the visible in fog.

Flashers

It has directed light and is normally equipped with reflectors. They are thus effective

during all light conditions and visible for long distance. Since flashers provide narrow row of

light it is important to carefully focused the flasher to required place.

Electrical Lamps

By using electrical lamps can light up open cuts along pedestrian side walks and road work area boundry when construction activities held in night.


GOSTOP


Flags

Where road works are in progress the narrowing of road carriageway may permit only single file traffic and it may become necessary to provide for control of traffic at the two ends. Manual control of traffic is done by two workmen carrying red and green flags at the two ends and permit only direction at a time.

Stop and Go sign

The stop and Go sign may be used as an alternative to flags to direct traffic at road work

areas.

300 mm dia

400 mm

Figure – 15 Stop and Go signals

It is important to perform flagger job reliable way since safety of the workers as well as

public safety in his hand. He must be trained well, must wear a reflective safety vest for

visibility and also enable to drivers to easy identification. The flagger behavior can influence to

the drivers to obey.

Base construction

The base construction that is an aggregate lay over the prepared sub base layer. After the unloading the ABC material, it is spreader with Motor grader to required design height. Surveying does the requirements of layer level. Then, small amount of water is added to the layer and it compacted with Tandem roller (8 – 10 tones). While rolling, the aggregate added or removed to required level. The rolling shall continued until the aggregate does not shift or wave in front of the roller.



Task – 2:3

Drainage structures and construction

Introduction

Drainage is probably the most important aspect that determines the performance and failure of road is often attributed to poor drainage.

Water when allowed to entire the road structure has the effect of weakening the pavement layers. Water can enter the road structure in one of two ways; either by storm water directly penetrating the surface or indirectly by wound water infiltration.

The water that falls on the road needs to be led away in a controlled manner. If allow to flow too fast it will cause erosion of the edges, drain and embankment slopes; if allowed to flow too slowly will cause sedimentation in drains and culverts. The typical drainage system shall be arranged at side of the road to flow the water of the area.

Types of line drains are:-

‘U’ drain

Dish drain

Kerb drain

‘U’ drain

U drains are constructed when high amount of water flow along the road side due to heavy discharge. Normally, these are constructed at town areas. Because of this wall has good strength and small space required for section construction than other types of drains such as random rubble masonry drain and earth drain.

Figure – 16 Details of u drain

Dish drain

This drain is provided when the surface water flow through the drain less. And it is also less construction cost than constructing the U drain.



Kerb drain

This drain is provided near to fence type of boundaries. So it will protect the water entering into the nearby residential area from drainage structure. And also this kerb drain may be constructed along the roads which have small lane width.

Cover slabs

When the drains construction between through an access people and vehicles can’t travel through the area. Therefore the concrete slabs are laid on the drain, which is called cover slabs. In this construction, T16 reinforcement and grade20 concrete were used. Dimensions of cover slab are 150*500*750. Cover slabs are placed by JCB and Tractor.

Excavation of trench

Drainage system for remove drained water as raining or flood from the street. In our construction these roads are exciting but don’t have drainage infrastructure. In my responsible area has U-drain channel. These drainage structures are producing design level of the road in the edges and also producing the edge of the road line. We cleaned and prepared the site in the edge of the road. The edge of limit is probably the fence or wall foundation neighbor houses.

Setting out was carried out by the surveying with leveling instrument. In the road surface has chainage at point in every 20 m intervals. The reduced level of the trench bed and width of the trench is given by the surveyor. According to the dimension the trench is excavated .During U- Drain Excavation had considered the allignment and road’s width.

Allignment of the excavation trench had take place straight line and also achieve the width of the road as wider as possible the width of the trench is up to width of the channel and for working space its u drain has 350mm and 450mm channel width trench width should be 750mm, 850mm

Excavation was carried out by JCB according to these setting out and alignment and excavated soils are damped at damping yard after the excavation can give invert level in the trench by leveling instrument to trim and compact the bottom level

Placing the reinforcement

According to the details of reinforcement the bar bending work was done at Yard and brought to site when it is needed. Before placing the reinforcement, polythene sheet was placed between ground surface and concrete to protect the water loss from the concrete. The cover was 40 mm in the bottom and side wall of the U drai



Formwork for u drain

Shuttering is a temporary structure to keep concrete as it shape up to settle the concrete or up to loss its consistency it should be about one day. After finishing the above work, form work is done according to the dimensions that given in the above detail drawing by wooden form work as shown below.

Concreting

Grade 25 concrete was used for concreting work. Before the concrete is pored into the form work it was tested at site by doing the slump test and cube casting.Required slump height should be between 100 to 150 mm.

After the concrete is pored into form work, porker vibrator (1” diameter) was applied to give the vibration for better compaction of concrete.

Curing

After the concreting the concrete is cured by applying water every day. The water is

applied on a sack which can keep water for long time. So it provides water to concrete for

long time to reach better curing.

Method of constructing the dish drain and kerb drain were similar to the

construction method of U drain. But there is no reinforcement provided into the dish and kerb

drains.

ABC LAYING PROCEDURE

As a first step of the construction, road finish level at the center and the 5 .5m from

the center were marked on the pegs..

Then depth at the center and the 2m, 3.7m and 5.5m away from the center were

measured and noted down on a sheet. This sheet is called “Dip Sheet”.

Then considering the minimum thickness (150mm) of the base layer,. If the depth

over the existing surface was not sufficient, scarify of the motor grader was applied

and existing surface was removed.

If there were sufficient depth at all places, can lay the ABC with tipper truck.



A motor grader was applied for spread the A.B.C and leveled the surface. The plate

of the grader can be used to spread and level the A.B.C surface exactly and the scarify

plate can be used for scarify the compacted A.B.C surface.

After spreading the A.B.C to the level little higher than the required level, water was

applied to it using water bowser. There may be a possibility of segregation of material

because due to application of water, quarry dust may go inside.. The ideal amount of

water is just sufficient enough to bond the dust of the A.B.C to the large metal

particles of it.

Afterwards A.B.C was spread and level of the surface was decreased as suited. The

base thickness of 200mm was constructed as two layers.

In the first layer it was constructed to a thickness of 75mm and at the thickness of the

final layer was 125mm.

The thickness of the final layer was kept little more than the first layer to avoid the

failure of the base by shear off the top layer.

When spreading the final layer it was important to level the surface exactly. In this

case A.B.C was spread and leveled to a level about 15 mm more than the base finish

level..

Then roller was applied once on the A.B.C surface and level was checked..

Then depth was measured using steel tape.

Then corrections were done if any. When doing the correction of the level of the

A.B.C it could not be done as soil.

Whenever level is higher or lower the surface should be scarified and all the material

should be removed. Then if the level was high some amount of material should be

removed and in the case of insufficient level some amount of material should be

added. Then material should be placed at the scarified place and should be compacted.

In our site, the dip measurement should be around 85mm before compaction and

should be around 100mm after compaction.

To compact the A.B.C surface 7.lton twin drum vibrating roller was used. When

applying the roller it was applied from the edge of the road to the centre. The number

of passes to get sufficient compaction depended on the site observations.



Compaction was done until there was no wheel marks on the surface. In the proper

compacted surface, it was hard to see the metal particles and whole surface was

covered with quarry dust.the compaction shall be tested.

Degree of compaction > 98% of maximum dry density.

If filed density test was satisfied we can continue the prime coat otherwise, we want

to do compaction again

Prime coat

This work shall consist of an application of a prime coat on a base. It using to provide. a proper bond between the layers ,to harden the base surface, to waterproof the surface of the base. to provide adhesion between wearing course and the base.

Application of prime coat

After the ABC surface was well dried ,the surface was brushed and all the quarry dust on the surface was removed by means of a rotary broom and air compressor.

The brushing force should be sufficient to dislodge all adhering material without damaging the pavement surface. Clay and other foreign material should be removed by hand brooms. The cleaning work continued until the entire surface shows a pattern of exposed large particles free from dust.

The next step was applying the prime coat on that surface. M.C 30 was used for the prime coat. The prime heated to 45C-60’C temperature for application.

Two methods were used for apply the prime.They are, using of mechanical spreader or a tar can. In the case of mechanical spreader the specified amount can be applied.

when using the tar can for this purpose it was very difficult to control the rate of application and normally it was almost twice the specified amount compressor.

In our site,the prime applied by mechanical sprayer. The specified rate of application of this prime coat was 1 l/m. so that at the start of each run the distributor shall be travelling at the correct speed for the instructed application rate.

The sprayer speed was 5.5m/s.There should be no leakage or drips of oil, diesel or bituminous material from the distributor. Traffic should not permit on the primed surface for a 3-4 hours.



Table – 5 Relationship between prime coat and temperature

Prime Coat Type Temperature (Degree Celsius)

MC 30 or 45% Cut back bitumen 40 – 70



Single bitumen surface treatment (sbst)

After prime application (minimum after 4hr), The surface repaired with patching at depressions or damaged area and surface had cleaned from durst and dirt with air compressor.. Then polythene was placed along the street centre because centre line area get 50% binder only due to spraying. The MC 80-100 bitumen was applied by sprayer at around temperature 180o C. Immediately after application of binder spread aggregate ensuring uniform spreading. These aggregate is 19mm size and also well washed and prepared those surface free from dust, dirt and wet.Then rolled by pneumatic tired roller continually until all the aggregate was well embedded in the binder.The combined roller also used after pneumatic tyre roller compaction. The tray test was done during spray the binder and aggregates by laboratory technicians.

Double bitumen surface treatment (dbst)

This is the finish level of our road construction. These chips were 12 mm aggregate and pre coated.Traffic allow on the first seal a period about two weeks before DBST. Bitumen spreading, aggregate spreading and rolling are same as SBST.

Asphaltic concrete surfacing

The asphaltic concrete surface shall consist of a binder course and a wearing course or wearing course only as specified. In our site, the wearning course only used as specified.

The surface course is the layer in contact with traffic loads and normally contains the highest quality materials. It provides characteristics such as friction, smoothness, noise control, rut and shoving resistance and drainage. In addition, it serves to prevent the entrance of excessive quantities of surface water into the underlying base, sub-base and sub-grade. This top structural layer of material is sometimes subdivided into two layers



Asphalt laying procedure

The asphalt laid on half side of road in one time because should allow traffic. After one day or some day, we can apply second half side.

The surfaces of pavement shall be corrected to the required width and profile as instructed

Where asphaltic concrete surfacing are laid on existing pavements,. All potholes, ruts, depressions, and damaged edges shall be corrected.

The surface is cleaned with mechanical broomer and air compressor

First provided “c” channel along the centre line of road within particular chainage. The thickness of “c” channel was 50mm. the vertical surface can get at centre line due to use c channel.

The mix was transported from mixing plant of ORU Mix Asphalt (PVT) Ltd in suitable tipper truck.that vehicle has heat insulation facility also.

Before pacing mix should apply the thin uniform coating of tack coat on earlier

asphalt surface. When laying second half side, the edge of previous asphalt surface

(around 2” or 3”) cut by breaker. Because that area could not get well compaction

during earlier compaction work.

The Asphalt mix shall be laid immediately after transporting, by asphalting pavers.

They shall be capable of spreading, finishing and providing initial compaction to the

mix . In narrow widths and in restricted areas where the paver cannot operate, the mix

may be manually laid.

When mix laying, the temperature of mix was 150.C and applied for 50mm thickness.

Rolling shall commence as soon as the material temperature became to 120.C by means steel wheeled rollers.

After some minutes pneumatic tyre roller used to rolling. That roller give compaction and finishing to asphalt concrete surface.

The bituminous mix shall not be laid during rainy weather or when the surface on which it is laid is damp or wet.



Table – 6 Relationship between rollers and their speed

Type of Rollers Breakdown

speed (km/hr)

Intermediate

speed (km/hr)

Finish speed (km/hr)

Steel Wheeled Rollers 3 5 5

Pnumatic Tyred Rollers 5 5 8

Vibratory Rollers 5 5 -

PROBLEM ENCOUNTED DURING THE DRAINAGE CONSTRUCTION

In certain places centerline of the road is erased, that causes very difficult during the setting out. If the places like circular curves that problem is much severe. In order to over come that problem we shifted center line tonic pins around 300 mm during the ABC laying other wise ABC layer hide the tonic pins.

In some places we need to excavate the entrance of factories, shops and houses. Due to that people are much suffered, they try to make compliance about us to consultant as well as client. Our staff facilities and other resources are deficient due to that some times delay occurred to the particular job. We provide temporary support over the trenches in order to prevent inconvenience to the public.

Underneath the trenches there are a water line pipelines going on. We used backhoe loader to excavate the trenches. In some situation pipelines are possibility blast. If we suspect that area we used manual method for excavation.

During the excavation adjoin to the trenches there is a possibility to tilting the concrete post. In order to prevent that damage we provide support to the concrete posts.

One instance traffic is divert in to one lane of the road as a result there is a heavy traffic flow in one lane, vehicles are try to use shoulder due to this congestion hereby heavy load imposed on back side of the drain wall, soil is dispersed and imposed too much load on to the drain wall due this drain wall is break. In order to over come this we restrict the traffic flow in to the shoulder.



Quality tests

More tests carried out in road construction for quality maintenance. Such as CBR test , marshall test , extraction test , proctor compaction test etc.

I have learnt proctor compaction test , field density test, penetration test , tray test and extraction test

Proctor compaction test

Soil compaction causes decreases in air voids and consequently an increase in dry density. This may result in increase in shearing strength. In the laboratory, the dynamic compaction test that the proctor compaction test is tested for determining the moisture – density relationship of soils. From the compaction test, the maximum dry density (MDD) and optimum moisture content (OMC) of the soil is found for the selected type and amount of compaction. The OMC of the soil indicates the particular moisture content at which the soil should be compacted to achieve MDD. The MDD in the proctor compaction test lower value indicating weaker soils.

TESTING PROCEDURE

The soil to be used in the test is first air dried and passed through a 20 mm test sieve.

It is then mixed thoroughly with a small amount of water and compacted into the

mould in 3 equal layers.

The mould is placed on a detachable square metallic plate and it carries a detachable

color.

Each layer being compacted by 25 blows of the 2.5 kg rammer dropped through a

above the soil surface.

After the completion of compaction the detachable collar was removed .

The soil is trimmed to the top of the mould and weighed with wet soil.

The little amount of soil was taken out from the mould into a can.

Then the weight of wet soil + can was measured.

After 24hours dried soil with can was measured.

The test is repeated five times with gradually increasing water contents until the

whole of the relevant range of water content has been covered.



Field density test

This test is done to find the degree of compaction in a compacted surface. This method is based on sand cone and the procedure is given below. the Compacted base/sub base layer is excavated in the site by placing a metal tray, which has a circular hole and compacted soil was excavated like circular shape.

The depth of excavated hole should be 150mm but in our site that was 120mm to 130mm according with consultant design. The weight of the soil removed can be measured. The volume of the hole can be obtained by filling the hole with sand (density of the sand is 1.307 g/cm3).

The volume of hole was found and calculated wet density of soil from excavated material.After that the sample of base/sub base material was taken out and it was under taken to the test to found the water content. Finally dry the density of the sample of material was calculated and the degree of compaction also can be calculated.

The standard proctor compaction density value can be compared with the field

density. Field compaction density is usually specified to be above 98% of the standard

proctor compaction test in the laboratory for sub base and ABC materials layers. If not

further compaction is necessary.

Calculation for Degree of Compaction

Volume of the hole = Weight of sand∈theholeDensity of the sand used

Wet density of the soil = Wet soil∈the excavationhole

Volumeof the hole

Dry Density of the excavated soil = Wet Density∗100

(Moisture content of the soil+100)

Degree of Compaction = Dry Density of the Excavated soil∗100

LabMaximumDry Density



Tray teat for surface dressing

When laying DBST 1st seal and 2nd seal, we should be do tray test to find application rate of bitumen and aggregate. First weighed the tray.then when laying binder the tray put under the spraying bowser and collected sample. The weight of sample was measured. The weight of aggregate sample also measured same as binder.when laying 1 st seal aggregate size was 19mm and for 2nd seal size was 12.5mm.

The specified spray rate of binder is 1.0 l/m2 to 1.3 l/m2

The specified coverage rate of aggregate is 1.3 m3/100m2 to 1.7 m3/100m2

Calculation

For binder

Weight of binder (kg) =[weight of (binder + tray) – weight of tray] / 1000

Volume of binder (L) = weight of binder (kg) / specific gravity of binder Spray rate (L/m2 ) = volume of binder / Area of tray.

For aggregate

Weight of aggregates (kg) = [weight of (chip + tray ) in g – weight of tray in g ] / 1000

volume of aggregate ( M3 ) = weight of chips (kg) / bulk density of chip (kg/m3) coverage rate (m3 /m2 ) = volume of aggregate (m3) / area of tray (m2)

Specific gravity of binder = 1.015

Bulk density of aggregate = 1388 kg /m3

Area of tray = 0.09m2

Area of tray of chips = 0.25 m2

Extraction test

The method described is a procedure used to determine the asphalt content of asphaltaggregate mixtures. The asphalt content is expressed as a percent



Procedures

Obtain representative samples of the asphalt-aggregate mixture (1200g)

The sample heated to 130 ْ C at oven.

Spread the asphalt mix sample in to the extraction apparatus (Rota test).

The sample covered specified solvent. Normally petrol used as solvent but in our site

hot kerosene was used five times and petrol used two times.

Turn ventilation equipment on and adjust for maximum suction from the extractor and enclosure.

Rotate the bowl back to distribute solvent and asphalt mix evenly in the bowl.

The procedure should be repeated until the extracted effluent has a same color of solvent.This is usually accomplished in 4 to 6 washings.

After the final wash, remove the filler screw and cover plate. Remove the filters carefully, clean the extracted aggregate from the filter papers and bowl and place in a clean pan.

The recommended drying procedure is to place the extracted aggregate in an oven at a controlled temperature of 120o C and dry to a constant weight.

Establish the required drying time by weighing after repeated heating and cooling until the weight is constant.

To prevent burning of the mineral particles, do not heat the aggregate above 120o C.

In a field quality control setting, the extracted aggregate may be dried on a hot plate or stove burner element. The method is more subject to burning of the mineral particles and is a less desirable method.

After cooling, weigh the dried aggregate to the nearest 0.1 g. Dry aggregate may absorb moisture from the air.

Determine the mass of the extracted aggregate immediately upon cooling to ambient temperature.

Record the weight of the dry extracted aggregate to the nearest 0.1 g.



Calculations

The following data is required:

Weight of asphalt mix before extraction = Wb

Weight of dried aggregate after extraction = Wa

Weight of filter paper before extraction = Wfb

Weight of filter paper after extraction =Wfa

Bitumen weight = Wb – (Wa + Wfb – Wfa)

Bitumen content = {bitumen weight / (Wa + Wfb – Wfa) } * 100 %

Machines and equipments

Backhoe loader

This is a popular machine in construction sites . The machine comprises of rigid

frame, a loader bucket at the front and the backhoe at the back.. It can turn through 90° in

plan. This can be used for excavations approximately 3m below the ground and it has a

maximum discharge height of 4.9m. The maximum out stretch of the bucket from the centre

line of the stabilizer is 5.3m. In this mode, machine must be stabilized using the jacks.

The 2m wide.0.7 m3 capacity front bucket was used as a loader and it has a maximum

discharge height of 3m.

Motor grader

This is an ideal machine for finish the surface smoothly without any undulations and

ridges. This consists of two major parts, the mould board and a ripper. Mould board is similar

to the bulldozer blade. It is hung between thy axels and position of the mould board can be

adjusted to suit the work. When leveling and trimming on the horizontal, mould board can be

set central or swung out either left or right. If the mould board set at an angle on plan,

material will roll off the blade to form a window. The ripper of the machine can be used for

scari the hard surfaces such as soil sub grade and aggregate base course.

Brand: GAL



Fuel consumption: 10 l/hour

Bitumen sprayer

This machine was used for applying the tack coat, the prime coat and also spraying

hot bitumen for DBST and SBST. This was a pedestrian control machine three persons

required to operate. One skilled person required for spread the tar and two persons required

for move the machine.

In this machine tar mix is heated using a kerosene flame and at the same time

recirculation the mix using a pump. The machine has a horse with a nozzle at the end and tar

spread by that. The capacity of sprayer is 3000L

Rammer

This is small-scale compacting equipment that can be transport and handle easily.

Mainly this was applied at the compaction work at the trenchers backfilling. In this machine

raising a heavy weight and allowing it to fall on the surface utilize kinetic energy. But at the

same time there are several disadvantages of this. This cannot be used for clay soil and it is

difficult to get exactly level surface. The detail of the rammer machine used is given below.

Brand: SAKAI

Model: RV 60

Power: 2.9kw

Weight: 60kg

Fuel: Petrol

Fuel consumption: 0.31/hour

Vibrating roller

This was the most suitable roller for the compaction works at the foot walk because of

its weight and the width. This has an ability to turn both front and the rare wheel and due to

that reason this may handle easily at the foot walk area.

Brand: SAKAI

Model: SW650



Weight: 10 ton

Pneumatic tyre roller

The pneumatic tired roller is recommending to be used on Asphalt work, SBST and DBST. The resilient tires on these rollers force the aggregate firmly into the each layer without crushing the particles. The most popular type of pneumatic tired roller for road maintenance is the self-propelled smooth tread tired roller with 3 or 4 wheels at front and, 4 or 5 wheels at rear. The driver can increase or decrease the tyre pressure during operation.

Weight: 15000kg

Engine: ESUZU AGBG1

Engine power: 68kw

Air compressor

Air compressor is a very useful machine in road projects. In this machine there is a power unit and several tools can be attached to this unit for various purposes. In this machine compress air is generate by means of an air pump driven by diesel engine. The normal operating pressure of the machine is 7kg/cm At this pressure 1 .5-2.0m of compressed air is required to operate one breaker.

The compressed air blow generate by the compressor can be used for several works such as cleaning shutters after fixing reinforcement, drying the wetted road surface and cleaning the road surface for laying SBST or DBST.

Traffic control during construction

Introduction

In road construction work, traffic controlling was done in a manner consistence with satisfactory execution of work involving improvement to existing road. A part of the existing pavement of the road carriageway under improvement or along temporary diversion constructed close to the road.

Traffic safety and control

All necessary safety to traffic during construction was taking by providing barricades, markings, flags, lights etc. The barricades were arranging firmly fixing steel rods to the ground, arrow-marking boards painted by using yellow and black background co lour. All



construction areas two flagmen’s kept, in road paving areas two security men’s kept with phones and red light torch.

Red flag and green flag / Stop and go board

When we doing some work on the road. We want to stop the vehicles. Then we can use this apparatus for it. If we want to stop the vehicles, we can lift there’d flag or stop board. After our work, we lift the green flag or go board.

Road narrow sign

These signs are used to give warning that the existing carriageway with becomes restricted. The type of restriction will determine which sign should be used.

Barricades are used to separate the working area from trafficked areas. There prevent vehicles and pedestrians entering the working area. Drams, Barrels or other types of containers also can be used as barriers. They should be painted while back found with a red strip about 300 mm wide around the middle.

Task – 2:4

Bridge

Bridges are designed to facilitate the safe crossing of pedestrians and vehicles over natural and man-made obstacles such as rivers,valleys,roads,canals and railways.

The earliest forms of bridges were the fallen log placed over a stream at a convenient point and the positioning of flat stone slabs on what may have previously been stepping stones.Both forms embody the simple beam principle.

The principle remained the basis of bridge construction until the industrial revolution,when the more modern materials of steel and concrete became available.The materials, together with a better understanding of structural design principles,provided engineers with a more economic method of spanning larger distances using suspension and frame techniques.

Components

Abutment

The side support at the banks providing resistance to both horizontal and vertical forces imposed on a bridge.stability is achieved by self weight or ground anchors.

Anchor Heavy- mass concrete block used to anchor suspension cables or cantilever arms.



ArchVertical curved beam used to carry heavy loads across supports.

Bearing Support between the deck and pier or abutment which carries the weight of the bridge.

Bolster:- See ‘bearing’

Catenary The curve which a uniformly loaded cable takes up when hugn between two points,e.g :-On a suspension bridge.

Deck That part of the bridge which carries the traffic loads and spreads them to the main structural supports.

Ground anchor Anchorage for surface structures provided by drilling holes into the ground,inserting rods or cables, and grouting them in.

Piers Intermediate supports between abutments,founded on firm ground.

Portals Towers providing high-level support to suspension cables.

Truss Frame work supporting bridge loads above the deck level.

Wing walls Side walls which retain an embankment.

Bridge construction

The methods of bridge construction vary from site to site and contractor to contractor.They are also dictated by many factors which include the size of the spans,the materials to be used; the restrictions imposed by the location of the site,its topography, and access limitations, the structural design principles; and usage of the area over which the bridge spans.

Bridge


d


Figure – 17 Bridge cum

Causeway

Figure – 18 Causeway

Elevation

Figure - 19 Bridge

Culverts

Culvert with openings less that 3 m

(d < 3 meters)

Figure – 20 Box Culvert


PierSuper structure

Sub structure

Abutment

Foundation


Figure - 21 Pipe culvert

Figure - 22 Arch culvert

Bridge openings greater than 3 m

(d>3m)

Figure - 23 bridge

One of the best ways to strengthen a bridge in a flood zone is to set the piers deeper into

the ground. The deeper the piers are lodged into the ground, the harder it is to knock them

over.

Major bridge

Foundation

Sub structure

Super structure


Sub structure cone or random rubble masonry

Capping beam

Foundation concrete

Pile (conc. or timber)

Rock


Foundation with concrete

Sub structure concrete or Random rubble masonary

Super structure Pre stressed concrete beam or reinforced concrete deck


Figure – 24 Foundation with concrete

bridge


Figure – 25 Clear sketch of the proposed bridge by marking all necessary components



Task – 3:1

Soil

γdry = 18 KN/m3

ф = 30 ْ

Ka = 1−sinØ1+sinØ

Kp = 1+sinØ1−sinØ

Ka = 1−1

2

1+12

Ka = 13

Friction coefficient between

Soilbase

= 0.4

Bearing pressure of soil = 180 KN/m2

No tensile stresses are allowed

Concrete

γconcrete = 24 KN/m3

Factors of safty

Fos = 1:2

Over turning 1:6

Step – 1

Draw earth pressure diagrams for active and passive cases.



Find out forces Fa – Fp with their respective line of actions.

Figure - 31

Active

0 ≤ Z ≤ 5

Pa = Ka γ z

Pa = 13

x 18 x Z

Pa = 6 Z

Z = 0 Pa = 0

Z = 5 →

Pa = 6 Z

Pa = 6 x 5 = 30

Passive

0 ≤ Z’≤ y

Kp = 1Ka

Pp = Kp γ z’

3 x 18 x z’

Z’ = 2m



3 x 18 x 2

Pp = 108

Pp = 0

1m strip

Fa = 1/2x 5 x 6x 5

= 75 KN

Ya = 5/3 = 1.66m

Fp = ½ x 2 x 108 = 108

Yp = 2/3 = 0.66m

Step – 2

Weight = volume x unit weight

W1 = 1x 4 x 1 x 24 = 96 KN

W2 = 4 x 1 x 1 x 24 = 96 KN

S1 = 4 x 2 x 1 x 8 = 144KN

S2 = 1 x 1 x 1 x 18 = 18 KN

Fa = 75 KN

Ya = 5/3 m

Fp = 108 KN

Yp = 2/3 m

W1 = 96 s1 = 144

W2 = 96 s2 = 18

Step – 3

Sliding



Sliding force = Fa = 75 KNResisting force = Fp + μR

R = W1 + W2 + S1 + S2

= 96 + 96 + 144 + 18

= 354 KN.

Resisting force = 108 + 354 × 0.4

= 249.6 KN.

RFSF =

249.675 = 3.954 > 1.2 => safe

Overturning A

= Fa × Ya

= 75 × 53

= 125 KNm.

Resisting moment

= Fp × Yp + S2 × 0.5 + w1 x 1.5 + W2 × 2 + S1 × 3

= 108 × 23 + 18 × 0.5 + 96 ×

32 + 96 x 2 + 144 × 3

= 72 + 9 + 144 +192 + 432 = 849 KN.

RMOM = 849

125 = 6.792 > 1.6 => safe

Bearing Pressure of soil



Figure - 32

Figure - 33

F = R = 354 KN.

M = Fa × Ya + W1 × 0.5 + S2 × 1.5 - Fp × Yp - S1 × 1

= 75 × 53 + 96 × 0.5 + 18 × 1.5 – 108 × 2/3 - 144 × 1

= 125 + 48 + 27 + 36 - 144

= 92 KNm.

F = 354 KN.

M = 92 KNm.

Soil pressure

Figure – 34 plan view



= FA

± MZ

A = 4 × 1 = 4 m2

Z= 16 × 4 × 4 m2

= FA

± MZ

= 354

4 ±

92166

= 354

4 ±

6×9216

(+)

= 354

4 +

6×9216

= 88.5 + 34.5

= 123 < 180 => safe

(-)

= 354

4 - 6×92

16

= 88.5 - 34.5

= 54 > 0 => safe


ctb - 1-4

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