Construction management

It is very necessary of 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. The law regarding contract, 2032 of Nepal has defined as an 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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Causes of landslide

The phenomena of sliding of weak and unstable soil, rocks and other materials from a certain height to the downside due to the action of gravity and various factors or causes which we will discuss below are said to be “Landslide“.

Mainly, a landslide occurs in hilly and mountainous regions where there is a high chance of having weak and unstable soils, rocks and sands. There are many trigger causes of the landslide. There are two kinds of causes of the landslide which are the most responsible for frequent landslide; Natural causes and human causes.

effects of earthquake- causes of earthquake

Causes of landslide

1.Natural causes of Landslide

Every existing in the surrounding is associated with nature. Everything present is gifted by nature and we are users of it and it’s nature greatness. But sometimes due to imbalance in nature or fluctuation in the operation of the ecosystem, there is great effect resulted in disasters known as natural disasters. For instance, landslide, soil erosion, flood, earthquake, .etc.

Among this Landslide is also caused by various natural causes. Some are explained below;-

A.Physical causes

 

Topography

There is a variation in the land structure somewhere there is plain land  whereas at someplace uneven, sloppy with different slope aspect and gradient and we  know that at sloppy area there is great chance of being weak and unstable land and at this place there is high pressure of water flow which causes devastating flood and finally resulted out as landslide too. Due to dip spacing under the roots of the tree from the surface,  there is the slow movement of bedding planes and along a line of weakness in a fault in a soil property cause landslide. And if the strength of large rocks is not good they rolled down and this process of rolling down of rocks with sliding it’s ways materials too is considered to be a landslide.

Tectonic Activity

Under the surface of the earth, there are many tectonic plates which are responsible to maintain the stability of earth’s surface thus we are capable of moving here and there and standing in one place. When these tectonic plates move unwisely the earth surface quakes which is said to be “Earthquake”. And the shaking of earth surface resulted out as various natural disasters among them landslide is one. Tectonic plates are above the molten liquid known as lava on the earth’s surface. So, Uneven movement of tectonic plates can cause the eruption of lava from certain area mainly from hills of rocks known as  “Volcanic Eruption. The volcanic eruption also can cause landslide which is more disastrous than other causes of the landslide.

Physical weathering

Due to variation in the geography of the earth, the weather differs from place to place. So, in some regions, there is cold, moderate, hot, etc. and weather causes disturbances in the ecosystem of the earth and leads to many kinds of problem like weakness in the quality of soil, rocks, roots of trees become weak to hold soil and landslide occur. And also cause soil erosion and in mountainous regions, there is snow, glaciers whose effect as thawing, freeze-thaw, etc. resulted in landslide causes great loss of property and lives.

 

Hydrogeological  Factors

At a dense forest area, there are great possibilities of heavy rainfall. And Heavy rainfall is a frequent trigger cause of the landslide. Hydrogeological Factors which can cause landslide are Geomorphology, soil types, and elevation. And slow snowmelt can cause avalanches flood. 

B.Morphological causes

On the sloppy land, there is a high possibility of glacier erosion, soil erosion, wave erosion( erosion due to movement of waves of seismic waves), fluvial erosion(erosion with the flow of water of streams), etc. And the change in vegetation can bring change in climate change and finally landslide.

C.Geo logical causes

 

Permeability contrasts

Depending upon the porosity of rock(cracks or cavities of the rocks ) there is a measure to identify the easiness of flow of fluid through porous rocks. And this measure is known as Permeability contrasts. If we are unable to find out porous point in rock there is high of landslide with forceful flood and rocks sliding down.

2.Human Causes of Landslide

Due to unwise use of resources available in nature by human various problems are causing with very impact on nature and living beings. Some of the Human causes responsible for a landslide are described below:-

  • Deforestation:
    causes of earthquake
    Chopping down of plants is termed as deforestation. With the development, the rate of deforestation is also increasing day by day which is the result of the need for the high population of users. Human chopped down plants for their benefits like for furniture, foods, as raw materials for the operation of industries and factories, etc. They are destroying forest but they are messing up the various natural disasters. They can use forest but also they heal the loss of greenery by planting more plants than they chopped down. We all know that plants’ roots are responsible to hold soil and not to let it slide down. With an increase in deforestation probability of landslide increases at a high rate.
  • Excavation: The activity of using tools, equipment, or explosives to move some materials, rocks, soil, and for exploration, environmental restoration, mining and constructions is called excavation. During excavation surface of the earth’s shake and the area where this is done becomes weak and can result out as landslide at that place.                                                                                                                                      
  • Improper water management in the water resources like we can manage water resources like rivers, streams, etc. from over water flowing and as continuous water flow can weaken the soil and rocks. And the area with weak and unstable soil and rocks have a high chance of landslide.                                                       
  • Improper use of land for various constructions like roads, buildings, dams, bridges, and many more by destroying nature. Excessive use of land can cause urbanization and it has bad impact. For construction purpose various heavy equipment are used as rollers, crane, land piercing machines for drilling, etc. which causes vibration and surface shake and landslide occurs.                                                                                                                                                        
  • For quarrying(the process of extracting materials, from ground or crushing rocks by blast furnace,etc. ) and Mining (the process to extracting out precious and valuable substances from ground like gold, diamond, etc.) various tools are used like sheared materials, drilling  materials, etc. creates temporary  quakes in the surface and causes landslide.                                                                                    

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Earthquake proof buildings

Introduction to earthquake

An earthquake is the sudden shaking of the earth which releases the energy in the earth’s lithosphere causing the creation of seismic waves. It may be due to volcanic eruptions, moving of tectonic plates, the formation of the cave in small area or explosions. It is also called quake( or tremor or temblor). It is measured with a Richter Magnitude scale. Earthquake proof buildings are needed to be safe from earthquake and also to decrease the effect of earthquake.

(Note: During an earthquake, do not hide under the staircase because it is the weakest part of the buildings and structures.)

Earthquake Proof Buildings

The buildings that are able to resist earthquake and its effects is simply called earthquake-proof building. Making building earthquake-proof results decrease in loss of lives, properties, etc.

Building Types

“Increasing the earthquake resistivity of buildings makes it earthquake-proof.” So making building earthquake-proof and increasing earthquake resistivity of buildings is same.

The process of increasing the earthquake resistivity of buildings can be divided into 2 parts:

1. Increasing Earthquake resistivity of small buildings( Earthquake proof buildings – small buildings)

2. Increasing Earthquake resistivity of big buildings( Earthquake proof buildings – big buildings)

1. Increasing Earthquake resistivity of small buildings (Earthquake proof buildings – small buildings)

1.1: Introduction

             By taking some precautions and measures in site selections, building planning and constructions small buildings can be made earthquake resistance. Some of the precautions and measures in site selection, building plannings and constructions are explained below:-

1)Site selection

      The  building constructions should be avoided on

a)Near unstable embankments

b)On the sloping ground with columns of different heights

c)Flood-affected areas

d)On subsoil with marked discontinuity like a rock in some portion and soil some position.

Earthquake proof buildings

2)Building planning

       Symmetric plans are safe compared to unsymmetrical plan. Hence we should go for square or rectangular plans rather than L, E, H, T shaped. Rectangular plans should not have length more than twice of width.

3)Foundation

Width of the foundation must not be less than 750 mm for single-storey building and not less than 900 mm for storeyed buildings. Depth of foundation should not be less than 1.0 m for soft and 0.45 m for rocky ground. Before the foundation is laid remove all loose materials, including water from the trench and compact the bottom. After the laying of the foundation, back-filling of the foundation properly and then compacting of foundation should be done.

Earthquake proof buildings

4)Masonry

 In case of stone masonry

-Place each stone flat on its broadest face.

-Place the length of stone into the thickness of the wall to ensure interlocking inside and outside faces of the wall.

-Voids should be filled with the small chips of the stones with minimum possible mortar.

-Stone should be a break to make it angular so that it has no rounded face.

-At every (600 -700) mm distance use through stones.

 

       In case of brick masonry

-Use properly burnt bricks only.

-Bricks should be placed with its groove mark facing up to ensure better bond with the next course.

In case of concrete masonry

-Place rough face towards top and bottom to get a good bond.

-Blocks should be strong.

-Brush the top and bottom faces before laying.

In general walls of length, more than 450 mm should be avoided. Length of wall must be restricted to 6 m. Cross walls make the masonry stronger. It is better to build partition walls along the main walls interlinking the two.

5)Doors and windows openings

-Walls with too many doors and windows near to each other may collapse early.-Windows should be kept at the same level.

-The total width of all openings in the wall should not exceed one -third the length of the wall.

-Doors should not be placed at the end of the wall. They should be at least 500 mm from the cross wall.

-Clear width between two openings should not be less than 600 mm.

6)Roof

-In sloping roofs with a span greater than 6 m use trusses instead of rafters.

-Building with 4 sided sloping roof is stronger than that with two-sided sloping, since gable walls collapse early.

7)Chejjas

-Restrict chejjas or balcony projections to 0.9 m. For larger projections use beams and columns.

8)Parapet

Masonry parapet wall can collapse easily so it is better to build parapet with bricks up to 300 mm followed by iron railings.

9)Concrete and mortar 

        Use river sand for making mortar and concrete. It should be sieved to remove pebbles. Silt must be removed by holding it against the wind. Coarse aggregate of size more than 30 mm should not be used. Aggregates should be well-graded and angular. Before adding water cement and aggregate should be dry mixed thoroughly.

10)Bands

The following R.C. bands should be provided:-

a)Plinth band

b)Lintel band

c)Roof band

d)Gable band

For making R.C. bands the minimum thickness is 75 mm and at least two bars of 8 mm diameters are required. They must be tied with steel limbs of 6 mm diameter at 150 mm spacing.

If wall size is large, vertical and diagonal bands also may be provided.

11)Retrofitting

     Retrofitting simply means preparing a structure or building in a scientific manner so that all elements of a building act as an integral unit. It is generally the fastest and economical way to achieve the safety of the building. The following are some of the methods in retrofitting:-

Earthquake proof buildings

-Anchor roof truss to walls with brackets.

-Provide bracing at the level of purlins and bottom chord members of trusses.

-Gable wall is strengthened by inserting sloping belt on the gable wall.

-Strengthen corners with seismic belts.

-Anchor floor joints to walls with brackets.

-Improve storey connections by providing vertical reinforcement.

-Introduce tensile strength against vertical bending of walls by providing vertical reinforcement at all inside and outside corners.

-Encase wall openings with reinforcement.

2. Increasing Earthquake resistivity of big buildings( Earthquake proof buildings – big buildings)

2.1: Introduction

             Tall buildings are subjected to heavy horizontal forces due to inertia during the time of the earthquake. Hence they need shear walls. A shear wall is an R.C.C. enclosure within the building built to take shear walls. It is usually built around the lift room. These shear walls should be provided evenly throughout the buildings in both directions as well as from bottom to top. Apart from providing shear walls, the given following techniques are also used for making tall buildings earthquake-resistant:

1)Base Isolation

2)Using seismic dampers.

 1)Base Isolation

      This is an idea behind isolation to detach (isolate) the building from the ground in such a way that earthquake motions are not transmitted up through the building, or at least greatly reduced. The concept of base isolation is explained through an example of building resting on roller [fig a]. When the ground is shaking, the roller freely rolls but the building above does not move. If the gap between the building and the vertical wall of the foundation pit is small, the vertical wall of the pit may hit the wall. Hence 100% frictionless rollers are not provided in practice. The building is rested on flexible pads which offer resistance. This helps in reducing some effects of ground shaking to the building. The flexible pads are called base-isolator, whereas the structures projected by means of these devices are called base-isolated buildings.

 2)Using seismic dampers

          Another method for controlling seismic damage in buildings is by installing seismic dampers in place of structural elements, such as diagonal braces. When the seismic energy is transmitted through them, dampers absorb part of it and thus damp the motion of the building. There are 3 types of seismic isolation bearings:-

a)High-density rubber bearing

b)Laminated rubber bearings

c)Friction pendulum bearings

Earthquake proof buildings

2.2: Some new techniques for earthquake-proof buildings

              Following techniques are some techniques for making earthquake-resistant buildings are discussed below:-

1)Haunches

As we know joints are most vulnerable during the earthquake and most of the structures fail due to failure of joints. Thus by increasing the strength of joints some resistance can be achieved. Strength of joints can be gained or achieved by simply using high strength or fibre reinforced concrete, or just by the increasing section near joints or provide haunches. This might be work as a knot as in bamboo. And thus provide stiffness to the joints.

2)Hollow foundation

As we all know secondary and love types of waves are most destructible among other earthquake waves. And the secondary waves can not pass through water media. Thus by the provision of hollow type raft foundation fully filled with water can be reducing some destructible effects of the earthquake. It may be filled with some viscous fluid, worked as a damper to reduce earthquake effects.

Two belts are to be provided within a bituminous layer in between. In experimental setups, it was found that the damage to the building is decreased very much. The upper belt is moved with reference to the lower belt by a few centimetres.

a)Bands

b)Isolator

Effects of landslide

The term ‘landslide ‘ is self-defined word i.e slide of land. The sliding down of weak and unstable surface materials (soil, sand, rocks,etc.) of the earth due to various causes like earthquake, heavy rain, gravity, etc is known as Landslide.

Landslide mostly occurs in sloppy land. And Landslide has disastrous effects.

On the basis of different kinds of landslide like sliding of rocks and soil, high pressure flowing water from streams, river and waterfalls, toppling, creeping, etc. there are various kinds of effects like property damage, loss of life of living beings, etc. It also has an adverse effect on the variety of resources available in nature. Landslide results in an imbalance in the ecosystem.

The probability of person travelling through road media has 1 in 5000 probability of dying but person travelling air medium has 1 in 1000000 probability of dying. About 20-30% of people who die in the road accident is due to landslide and rockfall. Rockfall is also a type of landslide. 

effects of earthquake- effects of landslide

Some of the effects of Landslide 

Landslide effect can be seen as a short and long period of time. So, here short term and long term effects of landslide are described below with some of the examples:-

1.Short-term effects of the landslide

Heavy loss of property and lives:-

Various precious properties made by humans like cultural monuments, their houses or buildings, dams, roadways and bridges, and many more. loss of human lives, loss of wildlife, .etc.

Change in weather;-

Landslide brings a drastic change in weather due to imbalance in the ecosystem in nature. And drastic change in weather can arise various problems like difficulty in adaptation, various diseases, etc.

Difficulty in roadways of affected areas:-

Transportation will be difficult for some days due to the blockage of the road to go from one place to another. This may cause great economic loss, one may have to face death due to block of the way to the hospital.

Pollution:-

Landslide may cause the death of humans and wild lives and improper management of their dead bodies lead to decay which causes water pollution, air pollution, land pollution, etc. that further cause various diseases.

Starvation:-

Due to the decrease in the fertility of the soil, the productivity of foods also decreases that may lead to starvation. And due to the destruction of small plants wildlife also have to face this problem that may lead to their extinction.

2.Long-term effects of the landslide

Destruction of various construction areas:

A disastrous landslide can destruct dams, bridges, roadways, etc. which may take more time to reconstruct again.

Change in the topology of the affected area:-

Landslide may cause uneven structure which used to be plain before. Gathering of rocks may be piled up at one place brings change in topology.

Loss of lives:-

It is heard that many people died in the landslide and some get injured. It is also a long term effect. 

Additionally, a landslide can cause many accidents by blocking the road. Due to quick and devastating landslide vehicles running in the roads gets collapsed when from sloppy land big piles of rocks and soil fall. In this accident, people get injured badly or some have to loss their life and vehicles get totally damaged. For few days roads get blocked and it causes the problem in transportation as well as in communication.

It damages and destroys homes which were made up of various dreams and happiness. Thus, it does not just destroy the structure form of the house, it destructs family members their happiness. Victims of the landslide have to face poverty, starvation, health-related problems, and they become homeless, etc.

Due to landslide piles of rocks, mud, sands, disposals and other substances get collected in the water resources like streams, rivers, waterfalls,  etc. And due to this kind blockage in such water resources, there may cause disastrous flood which causes another additional destruction int he surrounding.

In contrast, landslide causes great loss of infrastructure.

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