Some useful tips for footing excavation measurements

In this informative construction video tutorial, you will learn how to make calculation for earthwork excavation on the basis of elementary thumb rules. Besides, you will also learn how to make cross examination at the time of estimation.

This video is very useful for building engineer or civil site engineer.

Normally, earthwork is necessary for all the civil engineering projects roads, railways, earth dams, canal bunds, buildings etc.

This earthwork may range from either excavation or earth filling or sometimes both will reach out to as per the required shape and level.

Fundamentally, the volume of earthwork is measured from length, breadth and depth of excavation or filling.

The following items are included in earthwork :- Excavation, Backfilling, Disposal of surplus earth

Here, the calculation is done on the basis of IS Code 1200 for BOQ.

The calculation of earthwork billing is done in the following ways :-

1) Mode of measurement of billing – Types of measurement used for billing of excavation. It is done with the formula like Length x Breadth x Height/Depth

2) Different types of billing – a) R.A. Bill (Running Account Bill)
b) Find Bill

To get more details about the calculation of earthwork excavation, go through the following video tutorial.

Video Source: CE&T-Civil Engg & Technology

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Published By
Rajib Dey
www.constructioncost.co
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How impact of trench excavation on adjoining building is measured with rule of thumb

The adjoining buildings are greatly impacted with trench excavation and lead to settlement. This construction article briefly explains how to gauge the impact of trench excavation on adjoining buildings with rule of thumb.

The two factors are mainly responsible for impact of trench excavation on the buildings:

• Soil relaxation because of excavation
• Diminishing of groundwater owning to excavation

Soil relaxation because of excavation

When a trench is excavated adjoining a building, soil relaxation and subsequent settlement of the building is increased.

So, there should be sufficient support for the trench to resist soil relaxation. On the other hand, excavate the trench far from the foundation but it will not be a legitimate option always.

Besides, a rule of thumb is applied to examine whether the trench excavation affects the nearby building or not. Draw a line with 2H:1V from the bottom of the foundation. If the trench remains within this line, then engineer shall look forward to soil relaxation and eventual settlement of building foundation.

Lastly, if the soil at job site comprises of loose sandy soil, then draw the line with 3H:1V instead of 2H:1V.

Diminishing of Groundwater due to excavation: Generally, groundwater proceeds and seeps into the excavation from the adjacent areas of the trench. It will reduce the level of ground water in the trench vicinity area. Effective stresses are raised due to groundwater lowering and accordingly the foundation experiences settlement.

Last but not least, diminishing ground water raises effective stress in clay layer and higher effective stress leads to foundation settlement.

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Published By
Rajib Dey
www.constructioncost.co
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Details of Foundation in Construction?

A foundation alias ground sill is the low part or sub-structure of an architectural structure that is artificially constructed on the soil to transmit loads from the structure to the ground securely. Foundation of a structure is built up underneath the ground level with the purpose of making the lateral strength of the structure better. The solid ground on which the foundation is supported is known as the Foundation Bed.

On the basis of the condition and bearing ability of soil and nomenclature of structure, the foundation is categorized as shallow foundation and deep foundation.

If the depth of the foundation is under or similar to its width or if the foundation is built up at proper shallow depth, it is called shallow foundation. A shallow foundation delivers the load to a stratum found in a shallow depth. Shallow foundations are generally found in building up low rise structures.

If the depth of the foundation surpasses its width or if the foundation is developed at considerably large depth, it is call deep foundation. The deep foundation transmits the load to a wider depth under the ground surface. Deep foundation is intended for high rise or multi-storey structures.

1) Shallow Foundations
i. Spread footing or open trench foundations
ii. Grillage foundations
iii. Mat or Raft foundations
iv. Stepped foundations
v. Inverted arch foundations
vi. a) Wall Footing
vii. b) Reinforced cement concrete footing
viii. c) Combined footing
ix. d) Eccentrically loaded footing

Deep Foundations - i. Pile foundations, ii. Well foundations, iii. Caisson foundations

To erect a foundation, trenches are excavated thicker into the soil unless a solid stratum is attained. To make the base foundation, concrete is poured into this trench. These trenches are combined with reinforcement cage to raise the foundation stability.

The estimated steel rods which are provided outwards perform as the bones and should be attached with the substructure above. Once the foundation work is completed successfully, the structure of the building is started.

The construction of the foundation can be done with concrete, steel, stones, bricks etc. The material and the type of foundation selected for the desired structure depends on the design loads and the type of underlying soil.

The design of the foundation must incorporate different effects of construction on the environment. For example, the digging and piling works done for deep foundation may result in adverse disturbance to the nearby soil and structural foundation. These can sometimes cause the settlement issues of the nearby structure. The objective of developing of a foundation is to withstand the attack of injurious substances from outside.

The foundation for each structure is made by adhering to the following guidelines:-

1. The underlying soil beneath the foundation structure does not experience shear failure
2. The settlement should be occurred throughout the first service load or should have been within the limit
3. Acceptable bearing pressure should be described as the pressure the soil can resist devoid of any failure.

Objects of Foundation:

1. To allocate the load of structure on wider area to maintain the intensity of load under the safe bearing capacity of the underlying soil.
2. To allocate the load uniformly on the underlying soil to avoid any unequal settlement of foundation.
3. To arrange leveled and hard surface for the super-structure to be constructed over it.
4. To raise the strength of the structure completely against sliding, overturning or other distressing forces like wind, rain, earthquake etc.

For more information, go through the following article theconstructor.org

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Published By
Rajib Dey
www.constructioncost.co
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The duties and responsibilities of civil engineers

The main objective of civil engineers is to plan, design, build, operate and maintain roads, bridges, dams, water supply schemes, sewerage systems, transportation, harbors, canals, dockyards, airports, railways, factories and large buildings.

Civil engineers generally render their jobs in the following sectors - structural, water resources, soil and foundation, transport, airport, town planning or construction.

Duties of an airport engineer:

a) Having expertize in producing designs for airports, hangars and control towers
b) Administers the construction, maintenance and repair of runways, considering the factors like weight, size and speed of aircraft
c. If any technical issue arises throughout construction, guides contractors to solve the issue

Duties of a geotechnical/soil engineer:

a. Examines projected construction sites to determine the conditions of soil and foundation with by initiating drilling and sampling programs
b. Monitors and takes part in job site and laboratory testing of soils, and ensures that test equipment and machinery is arranged perfectly
c. Creates reports of test results and suggests proposals for providing the solution to engineering issues given in test reports
d. Creates specifications of soil mixtures which can be utilized in roads, embankments and other construction, and measures and provides suggestions on the required slope at cuttings and the density of soil dams and retaining walls.

Duties of a harbor engineer

a. designs and manages the construction of harbour facilities like breakwaters, navigation aids, navigation channels, jetties, wharves, heavy-duty pavement surfaces, cargo sheds and bulk handling plants for grain, ore and other cargo
b. Makes sure that the designs are created according to the needs of safety and serviceability
c. Optimize the use of funds and materials to fulfill the safety and serviceability requirements.

Duties of a harbor engineer:

a) Having expertize in evaluating population and growth statistics and traffic patterns and volume to fulfill the needs of future project
b. Discusses with government officials and other specialists to make the design perfect and secured traffic systems
c. Reviews roadway and embankment design, the geometry of highway interchanges and the maintenance of facilities like culverts and overpasses.

To gather more information, click on the following link civilengineerblog.com

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Published By

Rajib Dey

www.constructioncost.co

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