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Tuesday, April 25, 2017

Some useful tips for machine foundation design

Before starting the detailing work for foundations, the following general needs concerning machine foundations should be fulfilled and the results should be verified.
1. The foundation should have contained the capacity to bear the superimposed loads devoid of producing shear or crushing failure.
2. The settlements should have been inside the allowable limits.
3. The amalgamated centre of gravity of machine and foundation should have been maintained in the equivalent vertical line like the centre of gravity of the base plane.
4. There should have been no resonance, therefore the normal frequency of the foundation–soil system should have been either too big or too small with regard to the operating frequency of the machine. Toward low-speed machines, the natural frequency should have been high.
5. The amplitudes under service conditions should be maintained under allowable limits which are recommended by the machine manufacturers.
6. All rotational and correlating parts of a machine should be well-adjusted efficiently with the purpose of reducing the unbalanced forces or moments.
7. If necessary, the foundation should be planned in an efficient way with the intention of allowing a consequent adjustment of natural frequency by adjusting the base area or form of the foundation as may be essential afterward.

To read the complete article, go through the following link. theconstructor.org

Some useful tips for machine foundation design


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Published By
Rajib Dey
www.constructioncost.co
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Monday, April 24, 2017

Derivation of area of circle

This construction video will provide brief information on the formula derivation toward circle area. To estimate the area of a circle, the formula A=(πR^2) is applied. You will gather knowledge on the origin of the formula and the importance of it.
Here π stands for the ratio of the diameter of a circle to its circumference, and stands for the radius of the circle.
In geometry, the area surrounded with a circle of radius r is πr2. Here, π symbolizes a constant, roughly equivalent to 3.14159, that is the same as the ratio of the circumference of any circle to its diameter.

Go through the following video, to get the detailed process.



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Published By
Rajib Dey
www.constructioncost.co
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Friday, April 21, 2017

Fundamentals of Residential Construction 4th Edition – An exclusive ebook by Alexander C. Schreyer

Edward Allen, Rob Thallon and Alexander C. Schreyer have jointly published an exclusive construction e-book alias Fundamentals of Residential Construction. The book provides detailed guidelines on the each step of construction process for building up single family and multifamily home building. This book sheds light on each and every step associated with home construction which range from siting and foundations to finishing details. The book is enriched with more than 1,200 drawings and photographs whereas collaborative accompanying online resources facilitate in getting an overview of the material. This latest publication highlights the newest improvements in materials and methods, along with new coverage of sustainable building and energy efficiency, multifamily construction, prefabricated building components, and CAD/BIM planning tools in residential construction. Important exposure on wood light-frame construction, building systems, industrialized fabrication, insulating concrete forms, light-gauge steel and masonry construction, multi-family buildings, and more offers a solid understanding of residential construction methods, tools, and processes.
While constructing a home, sound knowledge is necessary for materials, structures, codes, and management processes as these can help in arranging the preparation of expertise essential for finishing a residential project successfully.
·         Be familiar with the pros and cons of common materials and systems
·         Gather knowledge on site preparation, foundations, and framing
·         Dip into the details of roofing, finishing, and energy efficiency
·         Recognize heating/cooling, plumbing, and electrical options
·         Explore through the newest codes, costs, and management best practices

Bar bending schedule offers the steel quantity requirement in a better way and thus delivers an option to make optimal use of the design in case of cost overflow.
The process becomes simple for site engineers to validate and approve the bar bending and cutting length throughout inspection prior to positioning of concrete with the support of bar bending schedule and thus facilitates in superior quality control.
It becomes easier to handle the reinforcement stock necessary for identified time duration.
It will facilitate to fabrication of R/F with structure.

Buy the book online from Amazon by clicking on the following link 
Buy Now



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Published By
Rajib Dey
www.constructioncost.co
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Fundamentals of Residential Construction






Download Bar Bending Schedule Of Box Culvert

Definition of Bar bending
It is the method of bending reinforcing steel into shapes which are important for reinforced concrete construction.
Definition of Bar bending schedule(BBS)
Bar bending schedule alias schedule of bars refers to a list of reinforcement bars, a specified RCC work item that is shown in a tabular form for a smooth view. This table sums up all the necessary particulars of bars ranging from diameter, shape of bending, length of each bent and straight portions, angles of bending, total length of each bar, and number of each type of bar. This information can be used for making an estimate of quantities.
It includes all the details essential for fabrication of steel like bar mark, bar type and size, number of units, length of a bar, shape code, distance between stirrups (column, plinth, beam) etc.
While generating bar schedules, it is important to take proper care about length. In case of bending, bar length will be raised at the bending positions.
Benefits of the Bar Schedule:
When bar bending schedule is applied along with reinforcement detailed drawing, it makes the quality of construction superior.
Once bar bending schedule is prepared, cutting and bending of reinforcement is performed at factory and shipped to job site. This improves quick implementation at site and minimizes construction time and cost as fewer workers are needed for bar bending. Bar bending also circumvents the wastage of steel reinforcement (5 to 10%) and thus project cost is saved significantly.
It offers the perfect estimation of reinforcement steel requirement for all the structural members which are applied to workout complete reinforcement requirement for whole project.
Bar bending schedule offers the steel quantity requirement in a better way and thus delivers an option to make optimal use of the design in case of cost overflow.
The process becomes simple for site engineers to validate and approve the bar bending and cutting length throughout inspection prior to positioning of concrete with the support of bar bending schedule and thus facilitates in superior quality control.
It becomes easier to handle the reinforcement stock necessary for identified time duration.
It will facilitate to fabrication of R/F with structure.

To download the excel sheet for bar bending schedule, click on the following link 
Download Sheet


Download Bar Bending Schedule Of Box Culvert


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Published By
Rajib Dey
www.constructioncost.co
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Thursday, April 20, 2017

Reasons for failure of bearing capacity on foundation

Foundation failure occurs due to variation on the load:
There exist three types of shear failure, i.e. General, Local and Punching shear failures which happened due to the compactness of soil and depth of footing with regard to its breadth (i.e D/B Ratio). When the utmost capacitybearing  of the soil is attained, it may fail in one of the following three failure type on the basis of the type of soil and depth to width ratio of the footing. A foundation can collapse in the following three diverse ways under loads :
Punching shear failure of foundation
General Shear Failure of foundation
Local shear failure of foundation
The above three types of foundation failure should be examined throughout design phase of concrete foundation for the specified load. Directives obtained through standard codes of practice should be obeyed so that foundation does not fail in any of the failure types as stated under any probable load combinations when structure is in use.
1.General Shear Failure
  • Under this type, the footing moves downward slightly and thus forms completely plastic zones and a sudden failure occurs with a significant bulging of the ground surface alongside the footing
  • It is based on clear-cut failure pattern, that comprised of a wedge and slip surface and bulging (heaving) of soil surface alongside the footing
  • Sudden collapse happens, together with tilting of the footing
  • This type of failure happens provided that dense sand or stiff cohesive soil support the footing
  • Failure load is apparent
  • The load-settlement diagram is equivalent to stress-strain for solid sand or over-consolidated clay
  • The ultimate load is apparent on this curve.
2. Local shear Failure:
Failure pattern comprises of wedge and slip surface but is transparent only under the footing. Slight bulging of soil surface takes place. Tilting of footing is not necessary.
  • In this mode a large deformation takes place under the footing prior to the formation of failure zones, i.e. large vertical settlement occurs prior to slight bulging of the ground surface
  • Tilting of footing is not necessary
  • Ultimate load is not clear
  • It occurs in moderately compressible soils or loose sand i.e occurs in soil of high compactness
  • Yielding occurs adjacent to the lower edges of the footing
  • Various yield developments may happen together with settlement in a series of jerks
  • The bearing pressure at which the first yield occurs is assigned as the first-failure pressure or first failure load
Reasons for failure of bearing capacity on foundation


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Published By
Rajib Dey
www.constructioncost.co
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Wednesday, April 19, 2017

How to work out cutting length for column circular stirrups

This construction video is recorded to provide you some useful tips for estimating the cutting length of the circular column stirrups.
Here the radius of the column is taken as 400 mm.
Dia of stirrup is taken as 8 mm
Concrete Cover is taken as 40 mm
Stirrups are also known as Links or Rings or Transverse Reinforcement. Stirrups are applied in Beams and Columns. The stirrups remain vertical in a beam and horizontal in a column.
Benefits of column stirrups :
To settle and withstand the longitudinal (main) steel bars in columns to bulging below the vertical forces (compression force) particularly in the middle of the column prior to get to the concrete.
Increase the quantities (diameter or by spacing) of stirrups at both ends of the column with the intension of combating the horizontal forces which produce horizontal shear forces on both ends of the column.
Go through the following video, to get the detailed process.


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Published By
Rajib Dey
www.constructioncost.co
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Tuesday, April 18, 2017

How to use method of joints for perfect truss analysis

This construction video tutorial is based on method of joint required for perfect truss analysis. (detect forces in various members of truss).

Trusses belong to structures which are extensively applied in various civil engineering applications like bridges, steel buildings and roof structures.

The method of joints is the most recognized process to discover unidentified forces in a truss structure. Under this process, all forces functioning on a joint must add to zero. If there exist a net force, the joint will shift. When a truss remains in equilibrium, then each of its joints should be in equilibrium. The method of joints comprise of satisfying the equilibrium equations for forces working on each joint.

Go through the following video, to get the detailed process.

How to use method of joints for perfect truss analysis

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Published By
Rajib Dey
www.constructioncost.co
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