Irrigation

Three basic needs of agricultural production/ Irrigation area unit are soil, seed, and water.

In addition, fertilizers, insecticides, sunshine, appropriate atmospherical temperature and human labour also are required.

 In several parts of the world, the moisture available in the root-zone soil, either from rain or from underground waters, may not sufficient for the requirements f the plant life. 

Necessity of Irrigation

Rainfall varies considerably in place, time and in amount. The intensity of rainfall is very high during the monsoon season and less during other seasons. So crop cannot be raised successfully over the entire world without providing artificial irrigation of fields. The necessity of irrigation is as follows:

– Non-uniform rainfall throughout the year

– Less rainfall than a requirement

– Increasing food demand

– Controlled water supply

irrigation

Advantages of irrigation

Every irrigation project is designed keeping in view of economics i.e. expenditure likely to incurred and benefit likely to occur. So any irrigation projection should be economically feasible. Generally, a project giving benefit at least about 8% interest of the capital outlay is implemented. Sometimes unproductive projects are also implemented in view of the general public benefits.

 The advantage of irrigation are as follows:

– Increase in food production

– Hydropower generation

– Elimination of mixed cropping

– Flood control

– Insurance against drought

– Inland navigation

– Forestation

– Facility of communication

– The prosperity of the nation

– Optimum benefits

– Domestic water supply

– Quality of life

– Employment

Disadvantage 

The disadvantages of irrigation are as follows:

– Creation of damp climate

–  Formation of water-logged area

– The necessity of crossing structure

– Creation of damp climate, marshy land and breeding place for mosquitoes causing the outbreak of diseases like malaria and dengue.

– Water pollution problem (seepage of nitrate applied in the soil as fertilizer may pollute underground water.)

– Raising the water table

– Loss of soil fertility

–  Soil erosion

– Loss of valuable land

 Source of water for irrigation

As we know every water is not suitable for human beings in the same way every water is not suitable for plant life. Water which contains impurities and is injurious to plant growth is not satisfactory for irrigation. Selection of sources of water depends upon the following factors: 

irrigation

a) Quantity needs

b) Quality factors

c) Location

d) Conflict and competition for water

a) Quantity needs:

The source selected for irrigation should have adequate quantity of water to fulfil the water requirements of the command area. If water is not available in adequate quantity, there will not be desirable yield of the crops in one hand and conflict between farmers in another hand.

 b) Quality factors:

 The concentration and composition of dissolved constituents in water determines the quality of irrigation use. The various impurities which make the water unfit for irrigation are as follows:

 i) Sediment concentration in water

ii) The total concentration of soluble salts

iii) Potentially toxic elements 

iv) Bacterial contamination

  i) Sediment concentration in water:

The result of sediment gift within the irrigation water depends upon the sort of irrigated land. When the sediment from water is deposited on sandy soil the fertility is improved but if the sediment has been derived from the eroded areas it may reduce the fertility or decrease the soil permeability. Sedimented water creates troubles in irrigation canals by causing canal siltation and by increasing maintenance costs.

ii) The total concentration of soluble salts:

 Salts of calcium, magnesium sodium and potassium present in irrigation water may cause injurious to plants. When these salts are present in the excessive amount they reduce the osmotic activities of plants and may cause injury to plant growth.

At the beginning of irrigation with undesirable water, no harm may be evident but with the passage of time, the salt concentration in the soil will reach a harmful level.

 iii) Potentially toxic elements :

A large variety of components like element, Selenium etc.may be toxic to plants. Traces of Boron are essential to plant growth but its concentration above 0.3 ppm may prove toxic to certain plants. Selenium even in low concentration is toxicant and should be avoided. Boron is essential to present in various soaps. Therefore soap water should be used with great care in irrigation.

 iv) Bacterial contamination:

Water contaminated with bacterias may be useful or harmful to plants according to the nature of bacteria’s towards plants.

 c). Location of source: 

Source of irrigation canal should be as near as possible to the command area. Nearer the source lesser the losses, Construction cost and maintenance cost.

d). Conflict:

Source of water selected should be free from conflict or dispute or the dispute should be managed. 

 

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Command Area

INTRODUCTION

The area over which canal irrigation water flows by gravity is known as the Command area. Following are the types of Command Area.

Command Area

Types of Command Area

1)  Gross Command Area:

Gross Command Area is the total area which can be economically irrigated from an irrigation scheme without considering the limitations of water is called Gross Command Area. It is denoted by GCA.

2) Culturable Command Area:

Culturable Command Area is the area in which crop is grown at a particular time or crop season. It is denoted by CCA.

CCA=GCA- Uncultuable area

Uncultivable areas such as excluded from GCA to obtain CCA. The culturable Command Area can be of two types. They are:

a) Culturable cultivable area:

It is the area within the culturable command area where cultivation is actually done at present.

b) Culturable uncultivable area:

  It is the area within the culturable command area where the cultivation is possible but not done at present.

3) Net Command Area:

It is the culturable Command Area obtained after deduction of canal networks, supply ditches etc constructed in the field. It is denoted by NCA.

NCA=CCA- the area occupied by canals, canals network and ditches.

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Building Substructure

Building substructure is the lower part of a structural system which is constructed beneath the ground level so, hidden from view. It transfers loads of the structural system i.e building, bridge, etc. to the ground which has the load-bearing capacity. It supports and anchors the superstructure in a safe manner. It should be designed with the proper technique because it assures the stability of superstructure too. Example:- the multistory structure has basement parking which is kind of substructure. 

Components of Building Substructure

Building Substructure has the following two components :

1.Foundation

2.Plinth Beam

1.Foundation

The structure just below the ground level with some extent depth which is directly contacted with superstructure is known as “Foundation”.It transfers dead loads, live loads and all other loads which are exerting on it to the soil with load-bearing capacity. As stability of building depends upon the strength of the foundation, it should be made more reliable and strong.

Earthquake proof buildings- construction management-Building Substructure

                 Types of Foundation

A.Shallow Foundation

It is the type of Foundation which is placed near the earth’s surface that transfers the loads to the soil at shallow depth. It is categorized into four types. They are explained below:-

a.Strip foundation(Strip Footings)

It is the foundation that supports the linear structure such as walls, columns which are constructed above it from the centre. It depends on the soil load-bearing capacity. The size and position of this Foundation depends on the width of linear structures.

b.Raft Foundation 

This is the kinda Foundation made up of a large concrete slab that can support the loads exerted by walls, columns constructed over it. It is spread all over under the building to reduce contact stress or pressure.

c.Isolated Footings

It is constructed beneath the column to distribute the concentrated loads safely to bed soil. It supports only for single columns.

d.Combined Footings

This kind of footings is built for supporting two or more columns in a straight line where soil bearing capacity is least that cause overlap between adjacent isolated footings.

Example:-Strap footings (cantilever) is the independent footings of two columns connected by beams.

B.Deep Foundation

This kinda Foundation is placed at great depth from surface level to transfer the load to the deep layers of soil beneath it. Such type of foundation can mainly be made out of steel, timber, reinforced concrete or pre-stressed concrete. 

For example; a good foundation which is made below the water level mostly for bridges.

Types of Deep Foundation

a.Pile Foundation 

A long cylindrical foundation which is analogous to a pole is said to be pile foundation. Such kind of foundation can be made of strong materials such as concrete, steel, timber, etc. so that it hardens the strata and transfers the heavy loads from superstructure below the ground level. It increases the effective size of a foundation and the resisting loads which are horizontally kept since, pile foundation is considered as more compact, less compressible and stiffer soil or rock at the depth.

b.Pier Foundation

Most of the foundations are depending on their instalment methods. Pier foundation is the dissolved form of pile foundation. Its caissons are the watertight structures which are made up of steel, wood or reinforced concrete built above the ground level and the sunken into the ground. This foundation can be constructed for the collection of a large number of columns, for repairing the ships and for the construction of the concrete dam as well. 

There are drilled shafts, those are the caissons or bored piles. They support structure with large axial lateral loads simply by excavating the cylindrical shafts into the ground just to fill them all into the concrete.

2.Plinth beam

This is a reinforced concrete beam which is in framed and structured form constructed between the wall and its the foundation. When the foundation suffers from the settlement, it is provided in such a way to prevent the extension or the propagation of cracks from its foundation into the wall above. Plinth beam is generally constructed in such areas which are prone to earthquake. It is effective to be used as it reduces the length of columns by reducing their slenderness, constructing as plinth line at the base of a column, statue, pedestal or the pier. Here’s something that needs to be noted, the strength of this plinth beam shouldn’t be smaller than 20 MPa. And the minimum dimension of the plinth beam is about 20 cm depth having with the matching width of the foundation. In order to prevent steel base from aggressive elements, the formwork for it has to be compacted sufficiently.

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Construction management

It is very necessary for construction management to control the money flow and to construct any structure under budget. There are three types of construction management:

  1. Organization
  2. Site Management
  3. Contract Procedure

1)Organization in construction management

      Organization is defined as a group of people put together to get the things done in a systematic way. An organization can be seen as a set of roles or positions rather than the collection of people. The posts or roles are arranged in a hierarchy.

1.1: Need for organization

1)To arrange the right people in the right position at the right time.

2)Organization facilitates in meeting management objectives.

3)Coordination Action for the achievements of the goal.

4)To explain the responsibility of workers.

5)To prompt decision.

6)Ensures continuity of work eliminates idle time and avoids friction between the staffs.

Earthquake proof buildings- construction management

1.2: Types of Organization

          Depending upon the size of organization and the pattern of the duties and responsibilities allocated with the organizational structure, organization, mainly used in the construction industry, can be divided into the following categories:-

a)line or military organization

           The line organization, which is simple and the earliest one. It is also called the military organization. In this type of organization the authority flows directly from the head of the organization to the bottom step by step and the officials who are at the top make all the major decisions.

b)Line and staff organization

            The line organization fails to handle large and complicated construction works, because of its simplicity and also it lacks experts. In order to execute such large and complicated projects, the staffs of the line organization need to be advised by the specialists to solve the various operating problems.

c)Functional organization

             The line type organization is unable to provide expert (specialist) service. This lacking of line organization has been fulfilled by the line and staff organization. But the “staffs” in the line and staff organization may remain ineffective due to lack of authority. A functional organization is the improved one among them. It is introduced by F.W. Taylor.

1.3: Responsibilities of civil overseer in construction management

            We know, overseers are playing the role of the supervisor in construction works. Overseers act as a bridge between engineers and labours. As a supervisor (or overseer) bears certain responsibilities which are listed below:-

a)To understand the duties and responsibilities of his own position.

b)To plan the execution of the work.

c)To divide the work among the worker and to direct and assets them in doing it.

d)To improve work methods and procedures.

e)To teach the subordinates.

Earthquake proof buildings- construction management

1.4: Relation between the owner, contractor and engineer

           Owner, contractor and engineer are the three parties involved in construction work. Owner contracts the work, contractors execute the work and the engineer by the owner provides advice and prepare all the necessary drawings, estimates, specification required and also helps in contracting procedures.

            Relations among owner, contractor and engineer depend on the nature of the work. They are supposed to perform. The owner gets the assurance of the work progress and the quality of the engineer. Contractors always try to satisfy the engineer, since he is the legal representative of the owner holding powerful authority. Thus, a relation of supervisory nature is to be maintained there by the engineer. He has to act as a supervisor.

2)Site Management in construction management

2.1: Preparation of site plan 

         Before starting any construction project, preparation of the site is essential. Preparation of site includes clearance of project area, construction of access road, labour quarter, storeroom, technical office, administrative office etc.

Construction management

2.2: Organizing labour

         It is the main element that plays a vital role to complete any construction work. so the proper management of labours before starting the project is most important.

2.3: Measures to improve labour efficiency

           All organized effort is done to achieve goals, in our purpose the goal is to execute any construction works. Though the goal of construction is primary, the person involved in the construction also has their own need and goals which are important to them. Several models have been developed in order to understand the complexity of people. However, the efficiency of labour depends upon the skill, knowledge, experience as well as willingness to work. It also depends on:- 

 a)Wages

b)Working condition of the site

c)Working hours

d)Rewards and punishment system

e)Employers behaviour

f)Tools and equipment introduced

g)The job of desired nature

2.4: Accident prevention

           The accident is an event that happens all of a sudden, unexpectedly e.g. hitting by falling from a height, collapse of deep foundation sites etc.

            Safety is the most important thing to be considered in the construction business. Unsafe working conditions not only cause minor accident or injuries but it may also cause the death of workers involved in construction. No compensation can provide a life for a dead person. The main causes of accidents may be broadly divided into:-

a)Physical causes

b)Physiological cause and

c)Psychological causes

       Following are the measures to prevent the accident:-

a)Protective hard hat (helmet)

b)Protective footwear

c)Protective hearing device

d)Barricades

e)Gloves, masks and goggles

f)Signals etc

 

3)Contract Procedure in construction management

3.1: Contracts

        The contract is defined as an argument enforceable by law. It is also defined as the agreement between two or more than two parties to do or not to do any business. It is now obvious that the contract involves a proposal from one party and an acceptance of the same by the other.

3.2: Departmental works and day works

         If the work is executed directly by the department or owner, all the required men, materials, the department manages tools and equipment etc. In short, the department shall handle all the administration and management for the successful completion of works. This procedure of executing construction work is followed if:-

a)The work is of regular maintenance and repair type.

b)The work is of smaller size and the expenses are minimum.

c)Government rules and regulations permit.

d)The work is of special nature.

e)This is of exceptional type.

Construction management

     Day work is used to denote a procedure of costing an item work on the basis of actual labourers and materials required. Certain item work on the basis of actual labourers and materials required. Certain item of work that cannot be measured as a design in the plasterwork, the front architectural finish of a building, work underwater etc. are valued and paid by “day work”. The “day work” prices usually include material, labour, transport, contractors profit and overhead charges, tools and plants etc.

3.3: Types of contract

           Construction work can be executed through the following contract procedures:-

a)Lump-sum contract

b)Item rate contract

c)Cost-plus contract 

d)Target contract

e)All in contract

f)Labour contract

g)Material contract

3.4: Tender and tender notices

            Usually, the construction of large and complicated projects, where the cost of construction will be high is not subjected to be executed by the department, directly. Government’s rule and regulation will limit the execution of such type of work by department. Execution of such type of work by contracting and for this tenders are called.

             Tender is a written presented before the owner or department in order to perform the specified works within a specified time under the agreed obligations.

            Tender notice is a means of expression, through which contractors may know where they have to bid a tender. Tender notice shall be published in such a way that all the concerning parties get the information in time. Thus, such tender notice shall be published in widely read newspapers or through other media from where the notification reaches the concerned parties. A tender notice shall contain the following information:-

a)Date, time and place of tender

b)Name of the authorities inviting tender

c)Nature of work and its location

d)Time of completion

e)Validity of tender

f)Amount of earnest and security money

g)Cost of the complete set of tender forms and conditions.

h)Estimated cost etc

3.5: Earnest money and security money

          Earnest money provides a guarantee of the party’s willingness to carrying out the work if he is awarded. This money is deposited while bidding a tender. 2.5% of the estimated amount or bidding amount (normally bidding amount) is demanded as earnest money. The earnest money deposited will be returned to the unsuccessful bidders. In the case of the successful bidder, the earnest 2.5% is turned to the security deposit with the addition of other 2.5%.

       On the acceptance of the tender, the contractor should deposit 5% of the tendered amount as security money with the department which is inclusive of the earnest money already deposited. It is also known as a security deposit. The amount is kept as a check so that the contractor fulfils all the terms and conditions of the contract and carries out the work satisfactorily according to the maintain progress and specifications and completes the work in time.

3.6: Preparation before inviting tender and agreement

             In order to execute construction work through contracting, we need to invite tenders from the eligible parties. Before inviting tender following steps are to be followed:-

1)Project formulation

2)Detail design and const estimation

3)Approval of cost estimation

4)Tender documentation

5)Tender invitation

     

        The agreement is a consensus between the successful bidder and the owner and it has a legal meaning. Agreement between the two parties should have the same spirit and understood in the same way.

3.7: Conditions of contract

            Construction involves owner, contractor and consultants. Thus in the agreement, there must be clauses or conditions which shall define the duties and responsibilities of the owner, contractor and consultant.

           Condition of the contract should be compared with the comparable standard form. The classes should not be ambiguous and incomplete. Here primary clauses of contract are given form the aspects of civil engineering contract procedure:-

a)Duties and power of site representative.

b)Definition of contract documents

c)Watching and lighting

d)Insurances

e)Notices and fees

f)Frustration

g)Arbitration procedure etc

3.8: Contract documents

        Following are the contract documents:-

a)Title page – Name of the work

b)Index page – Contents of the argument

c)Tender notice

d)Tender form

e)BOQ and schedule of quantity

f)Schedule of issue of materials

g)General specifications

h)Detailed specifications

i)Drawings

j)Condition of contract

k)Special conditions etc

3.9: Construction supervision

          Any supervisor or overseer deputed to the site should thoroughly supervise the work of a contractor. The best interest of the contractor will be always to keep the cost of construction as low as possible. A contractor guided by his best interest may try to cheat the owner by doing inferior work i.e. using inferior materials not following the instructions, without following time sequence etc. Thus, all the works shall be done in the presence of overseer, only in the confidence of an overseer further works shall be done.

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