Preparation For Construction

SITE PREPARATION (LEVELING)

The first step in the construction is site preparation. Site preparation consists of clearing away the trees from construction site, and doing whatever rough grading that is necessary in the installation of the footings and foundation. Clearing involves the removal of trees, roots, and other vegetation from the site. This can done using manual labor as well as excavators. The debris removed using a dozer.

After clearing the site, the undulations in the terrain have to be roughly leveled. Dozers used to level the plot.

SITE MARKING

Before the excavation of soil is started, the layout of the structure has to be marked on the ground. This process is called Site marking. This is a very important step, because here we begin the construction part. The slackness made in layout causes extensively damage to the work and heavy loss to the owner. If a building is constructed with an inaccurate marking, it can even affect the stability and aesthetics of the building. The center line, base line, etc. are fixed prior to the marking. Using pegs and ropes the layout for excavation is clearly marked to project the plan on the ground.

EXCAVATION

Excavation is the removal of soil from the surface to form a trench of required depth in which the foundation is built. Usually a backhoe or a digger (JCB) is used for this purpose. For smaller works manual labor is sufficient. The excavated soil can either be transported to some other place, or if back-filling is required, is dumped near to the trench or sideways.

COMPACTION

Compaction of back filled material is one of the most important aspects in the construction of structural buildings. Benefits of soil compaction are reducing its compressibility and increase its strength. By doing proper compaction of back filled soil, we can avoid lot of problems will arise later such as crack formation in ground floor

            In our site expedite the process, soil was just filled the required level and compact with vibration plate then filled the 100 mm above the required level and compacted till the required level. Level should be maintained from offline of thread. Spray water to soil during the compaction to increase the compact ability.

Benefit of Compaction

• Increase Load-bearing Capacity
• Prevents Soil Settlement (Better Stability)
• Reduce Water Seepage
• Reduces Shrinkage and others

     What is used to compaction?

     To compact soil, tamping rammer is used. 

  

     How to check whether it is properly compacted?

     To check whether it is compacted. Several test are carried out. One method is sand cone test.

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Mobilization

INTRODUCTION

After winning a contract, client has handover the land to the contractor to start the construction work. But the contractor can’t start the work just after he gets the site premises. The contractor should plan the arrangement of site. Without doing that, he can’t do his job properly. If the contractor starts the construction work without doing site mobilization, he will definitely be in trouble. So every contractor should mobilized his site according to the job he has assigned. That’s why in the tender documents and in the BOQ, that is clearly mentioned. The amount of money reserved for the mobilization is depends on the project. And also the duration for the mobilization is also clearly showed in the “Construction Master Schedule, (CMS)”. After providing the essential facilities for the staff and Labour contractor can start the construction work and while doing the work he can mobilize the other requirements of the site

MAJOR REQUIREMENTS

There are few items have to provide at the beginning of a project, by the contractor. Those are;

• Accesses roads
• Water
• Electricity
• Communication
• Site office
• Labour Accommodation
• Stores
• Bar bending yard
• Toilets

WATER AND ELECTRICITY.

    

     In any construction project, the most important material should be the water. Because we need water for many works carried out at the site. So at the beginning of project, contractor should find the water resources for the humans and for the construction work. Other important fact is Electricity. This is the main power source for the site work. This is very important, because there are so many equipment used at the site running by electricity. And also for the lighting at the night, electricity is needed. So at the first stage of mobilization, the contractor should provide these to resources.

  

      SITE OFFICE

     In any construction project, there is a staff to do the day-to-day work at the site. They are from the contractor’s party and consultant party. In multimillion projects, lots of people have involved to the construction work. They should be the project manager, construction manager, site engineer, quantity surveyor, or the consultant. So contractor must provide the office to them for get the proper output from them.

      Toilets & Showers

     When doing a construction project, lots of people are involved to do the work at site. They should be the staff, direct labours or indirect labours and many more. To all of them, contractor must provide the enough sanitary facilities.

      Labour Accommodation

     The contractor should consider about the Labour accommodation. Because most of them are in very far away to the site. So it is difficult to travel daily. Sometimes they have to work at night, due to mass construction. (E.g.: slab concreting). So to gain maximum output as well as to have good management it is necessary to place the Labour accommodation.

     It should be in the site or near the site. In our site we prepared a temporary huts for accommodating for labours.

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Soil Retention Systems

In a construction of a building, bridge, or whatever structure, main thing is a foundation. When doing foundation structure several soil retention systems are used. If simply said, that used to prevent soil without collapsing. And also prevent ground water comes to basement. That also known as “shoring system”.

In a deep foundation structure that soil retention system requires for,

• Secure Earth
• Groundwater prevention

Mainly the soil retention systems are used as a temporary structure. But some cases that retention systems are used as a permanent structure.

Temporary retention systems are just temporary. This is not to say that unsafe, but that design with understanding the place, soil type and load bearing for a finite time period.

In a case where the engineer decided to permanent retention system, most unstable soil or several reasons permanent retention system is used. ( E.g. Soldier pile, Soil nailing, secant walls, slurry walls, micro piles etc.)

Types of retention system depends on,

• Soil type
• Depth
• Whether it is temporary or permanent

Examples of Retention Systems:

• Sheet piles
• Soldier piles

Sheet piles

It’s a steel retaining wall. It’s done by using interlocking sheet piles. Using hydraulic pile machine we can drive it in to ground.

Advantages	Disadvantages
Inexpensive	Difficult to install the sheet piles if the soil is rigid
Can be re-use
Less joints
Light weight

Soldier piles

          Soldier piles are some of the oldest retaining system used in deep excavation. It is a temporary or permanent retaining system commonly used in urban areas. First drills the steel H-section piles and then installs the timber cladding.

 Advantages and disadvantages of soldier piling

Advantages	Disadvantages
Fast to construct	Can’t use in high water table conditions
It’s very cheaper
No need advance techniques
Easy to install cladding

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What is Civil Engineering?

Civil engineering is the oldest engineering field.Civil Engineering deals with the design, construction, and maintenance of structures or public works as they are related to earth, water or in space.Civil Engineering is also known as the mother of all engineering.

• Marvels of Civil Engineering
• Parts of a Building
• Types of Foundation
• Types of Building
• Regulations

                                               Download PDF

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Earth Moving Equipments

   When we start to construct a building, bridge, dam, road or whatever project we need various equipment such as bulldozers, backhoes, dredges etc.

Factors we must consider when we are selecting the equipment.

• Volume of excavation to have remove
• Area of excavation
• Soil type
• Duration of a project
• Weather condition

Advantages and disadvantages of using earth-moving equipment.

Advantages	Disadvantages
Use few manpower	High maintenance cost
Less dangerous accident by human workers. (collapse soil)	Required large working area
Can go to greater depth	At resting increase cost
Quickly done

Backhoe Excavator

        Back-hoe excavator is heavy equipment that consists with backhoe on the back and bucket on the front. It can use for multiple purposes. It travels on rubber tires. Backhoes are very popular in urban constructions. These machines use to dig trenches, dig small excavations. Basement excavation also can use this machine.  Front backhoe used to move materials such as sand, gravel and load to trucks.

Advantages	Disadvantages
Multipurpose machine	Can’t use in marshy aria
Low maintenance

 Bulldozer

          It is a simple very popular machine. It can easily work with soil. It is a crawler with substantial blade. It has various numbers of uses. It can push and pull only. It can push large quantity of sand, rubble, waste and such as materials. When clearing and grubbing we can use it. Generally if have a site maintenance, we have to use it.

Advantages	Disadvantages
Can drive in any soil condition	Only push and pull can do
Low maintenance

Front end loader

          It is a most popular machine found in most of construction projects. It can be rubber tire or track machine. A front end loader has bucket in front. That bucket use to load and unload materials and lift. Mostly it use to excavate and carry soils and also it used to transport the materials on site. 

Advantages	Disadvantages
Large area can covered	If it has rubber tires can’t drive in marshy land
	No multipurpose

Dump trucks

          Dump trucks for transporting large amount of materials such as sand, gravel and waste. Normal capacity range is 5-15m³. It has a container in back. Shape of the container is mostly large box. The container can be lifted up and down by using hydraulic power. Therefore load can be easily dumped.  

Advantages	Disadvantages
Large load can be transport	No multipurpose
Various capacity can be select	Can’t use in marshy land

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