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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How to measure the volume of silt content in sand

In this civil engineering video tutorial, you will learn some vital tips to work out silt percentage in sand or course sand to ensure that whether the sand is eligible to be used in concrete or not. It is recommended that the percentage of silt content of sand in concrete should be over 6%.

The silt stands for a very fine particle and the size of it is under 150 Microns. Silt content can be shrinked and inflated because of the weather condition. Therefore, it can impact the strength of the structure.

Impacts of Silt:

1. Crack will be created on concrete. (some cracks are found in the wall)
2. Silt content includes evaporated matters and salts. (mortar will be exposed at the time of plastering)
3. It engrosses more water. (broadened & shrink owing to the weather condition.

To determine the percentage of silt conent, the following items will be required :-

a. 250 ml, measuring cylinder
b. Course or fine sand
c. Water
d. Sand

The calculation is done as follow - Initially, it is required to area of cylinder as the cross sectional area from top to bottom will be same for the cylinder.

Area of cylinder = πr2 x Height

Suppose, the cylinder is filled with sand up to 100 ml, then water is added up to 50 ml. So, total volume will be 150 ml. Then, shake the bottle and wait for 2 hours. Now, it is found that the percentage of silt content in the sand is 5 ml. You can check the percentage of silt content in the following way :-

= Volume of silt (taken as V2) / Volume of sample (sand or course sand; taken as V1) x 100
= 5 / 100 x 100 = 5%

To get more information, watch the following video tutorial.

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Clear Cover and Nominal Cover used for RCC Structure

The concept of Clear cover and nominal cover is seen in the Reinforced concrete structures.

Reinforced concrete structures have been main structural materials for over a century and still the most popular material for public structures all over the world. The concrete structure is durable enough to keep its shape for a long time.

The reinforced concrete structure refers to the members like beams, boards, columns, and roof trusses etc. which are consisted of concrete and steel bars.

In these structures, the steel bars are covered by concrete but their mechanical properties will still lose due to the fire to destroy the whole structure.

In this design of reinforced concrete structures, the provided reinforced is inserted in the concrete upto a particular distance from the face of the member as there are some reasons.

The reasons are discussed below:

• It will provide protection to reinforcement from erosion
• It will also provide fire resilience to reinforcement.
​• It will also supply sufficient embedded depth so that reinforcement grows the requisite stress.

This distance is measured in various ways and known by different names like:

• Clear cover: This is the difference from the face of the member to the outermost face of the reinforcement including shear or torsion Stirrups or links.
• Nominal cover: This cover is like the same as Clear Cover although it has different name; actually the name is a term that is used by the code. It is the distance measured from the face of the member to the outermost face of the reinforcement including Stirrups or links.

To get information on other clear cover and nominal cover, go through this useful civil engineering video tutorial.

Video Source: CE&T-Civil Engg & Technology

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Published By
Rajib Dey
www.constructioncost.co
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Some common types of symbols in surveying

In surveying, the objects or an area is demonstrated with symbols not by names. The civil engineer and land surveyor should have adequate knowledge on how to read the drawings, maps and plans.

In this exclusive civil engineering article, you will be familiar with various types of symbols applied land surveying.

These marks are arranged to mark key survey points on the Earth's surface.

Given below, some vital common signs and symbols found in the field of Surveying:

Surveyor flags and tape: Sometime the flags or streamers are just affixed to trees, fence posts, or provided on a stake so that they can be seen over the weeds. There should not be any markings on the stake, or only simple generic markings.

It signifies that this is the proper road and turn here. It could also signal a projected or estimated location for some future work.

Stakes with simple markings: Flags having some type of identification (it may belong to names or numbers). It is suitable for a projected well pad access road location. No dimensions are provided on these.

Stakes having simple flags and basic identification: All the stakes demonstrated here, point to an access route applicable for equipment and trucks to attain a projected pipeline right of way. The “H310″ stands for the EQT name for the 30” OVC pipeline.

Control points: These three stakes are used to recognize a control point that remains outside the limits of disturbance (LoD). These markings encircle a pin to be applied for reference.

Limit of disturbance: The “L O D” here signifies the limits of disturbance. Outside this point, no trees cut or dirt moved should exist. The stakes signifies that this is the outside limit of where the contractor will be unsettling the original contour of the surface soil.

Pipelines: Stakes with flags and “center line” markings are suitable for pipelines. Here, the symbol is demonstrated for center line: a capital letter “C” levied on the letter “L”.

Precise location markings: Stakes like this will normally contain a steel pin connected with it. This stake provides the latitude, longitude, and elevation of the site.

Permanent property lines: The markings can also be done with this one inch steel rod having an alum cap and it indicates permanent property lines and corners of property.

To get information on other types of symbols, go through this useful civil engineering video tutorial.


Video Source: Civil Engineer Deepak Kumar

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Published By
Rajib Dey
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The details about bills of quantities

With the measurement of quantities, the total price can be evaluated more elaborately & precisely to give cost feedback on the job, that at the same time can be applied numerically in cost planning of other works.

Bills of quantities offer the best possible ways to manage the cost of variations in the contract. It is extensively utilized for various post-tender work like material scheduling; construction planning; cost analysis; and cost planning.

The method of working out the quantities prior to tender is a crucial test regarding what is drawn and stated can in fact be built. By examining the drawings and reviewing the construction in detail is definitely helpful in recognizing the issues which may be omitted initially.

The direct costs & indirect costs should be taken into consideration for determining the entire cost of the project which are included in various segments of the BOQ.

As the cost is identified prior to commencement of the construction, a superior level of price certainty is maintained for the construction project.

Facilitates to provide a low tender price.
Accommodates with design changes and assists the cost management process.
Provides superior quality of tender document.

Minimize the risk of contractors managing the information in the BQ for their own purposes.
Bypass the risks with regard to both time and cost since the projects are calculated on the basis of the overall floor area.
The valuation of progress payment becomes simple with detail information as given in BQ.

May pass up the tendency of contractor to build up a conspire group and bid high for projects.

Video Source: Civil Engineer

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How to design a gabion retaining wall with Tekla Tedds

In this construction video tutorial, you will learn how to use Tekla Tedds for making calculations of gabion retaining wall analysis and design with adherence to the Eurocode to verify the strength of a gabion retaining wall from sliding overturning. Besides, it is also possible to find out the maximum and minimum base pressure underneath the wall.

A gabion retaining wall is built up with stacked stone-filled gabions which are attached together with wire. Gabion walls are generally battered (angled back towards the slope), or stepped back with the slope, in spite of stacked vertically. Besides, galvanized steel wire, PVC-coated and stainless steel wire are also utilized. This type of retaining wall is very effective for erosion control applications.

Tekla Tedds is a robust software that can be used to automate your tedious structural calculations. The users can select from one or more of the extensive calculation libraries.

The users will also be able to write their own, and generate professional documentation every time. It is also possible to integrate the structural calculations with 2D frame analysis.

The users can get access to the following extensive library of design modules.

• Loading - Seismic and Wind
• Analysis - Continuous Beams and Rolling Load
• Steel Design - Beams, Torsion, Columns
• Connections - Base Plates and Bolts

Tekla Tedds offer the following benefits :-

a. Get access of an expansive library of structural and civil calculations.
b. Employ a single solution for all common components & materials.
c. Reap benefits from a simple and intuitive interface.
d. Generate apparent calculations which can be simply analyzed.
e. Make comparison among various design options and create modifications instantly.
f. Create consistent documentation.
g. Improve your Quality Assurance processes.
h. Obtain new and improved calculations and code updates regularly.

To get online demonstration of Tekla Tedds, go through the following video tutorial.


Video Source: Tekla Software

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Published By
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www.constructioncost.co
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Detail about 3D reinforcement in civil structure drawing

In this useful construction video tutorial, you will get the details of 3D reinforcement in civil structural drawing.

In this regard, you should have clear ideas on the followings :-

Stirrups 8Ø@150 C/C – It means the stirrups or rings should contain 8mm diameter. The distance among two rings in a column should be 150 mm center to center.

Bottom - 12Ø@150 C/C B/w (both way) – It is applicable in footing. The steel bars are placed horizontally and vertically in the footing. The distance among the two bars is 150 mm in both ways i.e. x axis and y axis.

3D reinforcement is provided in footing or foundation. It has the dimension like 12Ø@300 C/C three dimensional R/F.

Suppose the length, breadth and height of a foundation are 2m, 3m and 2m. Initially, the steel bars should be placed vertically at the spacing of 300 mm with 12mm diameter. It means the spacing should be maintained as 300 mm to both x and y axis horizontally & vertically for settling reinforcement. 3D dimensional reinforced is used to make foundation strong to bear heady load.

To get more clear ideas, go through the following video tutorial.

Video Source: Tutorials Tips

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Published By
Rajib Dey
www.constructioncost.co
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How to calculate mason, labor for brick masonry construction with help of thumb rule

In this construction video tutorial, you will learn how to compute the mason as well as labor toward a 1st class brick masonry construction with the help of thumb rule.

A thumb rule refers to a principle having extensive application that is not projected to be exactly perfect or authentic for each situation. This method can be easily applied for making approx calculation or recollecting some value, or for making some determination.

It should be noted that the quantity of required labor will be gradually increased from ground floor to first floor to second floor etc.

Thumb rule is a constant value that is taken from the earlier construction work i.e. how much volume is covered by the labors employed in earlier projects. All the volumes are summed up to find out the average volume.

In ground floor, first floor and second floor, the volume of total area is taken as 150 m3

Ground floor :-

Mason = Volume x thumb rule (for mason) = 150 x 0.71 = 107 numbers
Now, suppose the charge for one mason = 1100 rupees
So, the cost for mason will be 107 x 1100 = 117, 700 rupees

Labor = 150 x 1.18 (thumb rule for labor) = 177 numbers
Suppose, one labor charge 800 rupees
Therefore, cost of labor = 177 x 800 = 141,600 rupees

Similar process should be followed for 1st floor and 2nd floor. Here, the value of thumb rule will be increased as the steps are increase.

To learn the calculation for 1st and 2nd floor, watch the following construction video tutorial.



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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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What should be the properties of good RCC?

In this construction video tutorial, you will come to know about the properties of good RCC.

Given below, the details of properties :-

It should have the ability to withstand tensile, compressive, bending and shear forces.

In RCC, there should not be extreme deflection in structural members.

There should be perfect cover for reinforcement.

The materials in RCC should have the good resistance capacity against fire.

In fresh state, RCC should be moulded to any required shape.

The reinforcement that is utilized in concrete should be free from rust and corrosion.

To get more detail information, go through the following video tutorial.

Video Source: F&U-FORYOU

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Published By
Rajib Dey
www.constructioncost.co
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Setting out survey process – Definition and various benefits

Setting survey process is applied to set out the exact position of a projected structure inside the legal boundaries of a plot of land.

The objective of setting out is to set out perfect position & levels of building lines and road alignments for a projected structure as per construction plans by applying different techniques and instruments.

This type of survey is very vital while going to set up any type of construction work.

Generally, a set-out survey comprises of the process for transforming a building design onto the land itself in order that the builders can abide by the process throughout construction. Throughout the process, major points are set up and markers are applied for the progression of the building process and maintain perfectness.

For large scale projects like high rise buildings and developments, multiple set-out surveys are required as the construction advances. This type of survey is mainly undertaken for the earthworks, roads, car parks, sewerage, water and the actual buildings themselves.

Methods of Setting Out Survey

1. Setting out buildings by coordinates
2. Setting out with theodolite and level
3. Examining verticality

4. Setting out and alignment in steel framed buildings
5. Alignment and verticality in form work
6. Control and computation for route surveying

Setting Out Building by Coordinates

A building is set out by adopting referencing from an already established baseline. An asymmetrical building or a building with complicated geometry can also be established by applying the equivalent process. For each corner of the building, a grid line is set up from the baseline.

Examine Verticality - The verticality of points in a building is examined with the following surveying instruments:

1. Plumb Bob (For buildings less than 20m in height)
2. Optical Plummet (A transparent plastic sheet is used as a target for checking verticality of tall buildings)
3. Theodolite

Setting out Survey works also contains the following :-

Calculations and setting out Methods for:

1. Simple Circular Curves
2. Compound Curves
3. Reverse curves
4. Transition curves
5. Vertical curves

To get more details, go through the following video tutorial

Video Source: Finchley College

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Details of top down construction method

Under top down construction method, the basement concrete slabs function as lateral bracing toward the perimeter wall system. Ground level and first basement slabs are poured, with access holes left to facilitate excavation below. Since every succeeding sub-grade level is finished, the floors perform as lateral bracing toward the perimeter wall system.

Top-down method is mostly suitable for two types of urban structures, tall buildings containing deep basements and underground structures like car parks, underpasses and subway stations. In such a circumstance the basement floors are built up as the excavation steps forward.

The top/down method is utilized for deep excavation projects where tieback installation can’t be done and soil movements should be reduced. Top-down construction method saves the entire construction time. So, it is mainly implemented for some major projects where time is a key factor.

The sequence construction starts with retaining wall set up and then load-bearing elements to support the future super-structure. The basement columns (generally steel beams) are built up prior to starting of excavation and rest on the load bearing elements. These load bearing elements normally belong to concrete barrettes constructed under slurry (or caissons).

Construction method: Given below, the detail construction method for top down construction :-

• Built up the retaining wall.
• Build up piles. Arrange the steel columns or stanchions where the piles will be developed.
• Carry on the first phase of excavation.
• Cast the floor slab of first basement level
• Start to build up the superstructure
• Carry on the second phase of excavation; cast the floor slab of the second basement level.
• Reiterate the similar method unless the required depth is attained.
• Develop the foundation slab and ground beams, etc. Finish the basement work.
• Continue constructing the superstructure unless it is completed.

To learn the step-by-step process in detail, go through the following video presentation.

Video Source: geobuuk

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Rajib Dey
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Method of constructing post tension RCC slab

In this construction video tutorial, you will learn how post tension RCC slabs are built up as well as how post tensioning is performed and benefits of post tensioning process.

POST TENSION SLAB: It refers to the slab that is tensioned as soon as the slab is developed. Reinforcement is arranged to avoid the compression.

In Post tension slab, cables or steel tendons are utilized to substitute the reinforcement. Post-tensioning offers a solution to get rid of the natural weakness of concrete in tension as well as optimize its strength in compression.

In concrete structures, this is obtained by arranging high-tensile steel tendons/cables in the element prior to start the casting. If the concrete attains the required strength, the tendons are pulled with special hydraulic jacks and retained in tension with specially designed anchorages which are attached at each end of the tendon.

It creates compression at the edge of the structural member that increases the strength of the concrete for resisting tension stresses.

If tendons are correctly curved to a specific profile, they will exert, other than compression at the perimeter, a useful ascendant set of forces (load balancing forces) that will neutralize applied loads, alleviating the structure from a portion of gravity effects.

In this type of concrete slab, cables are affixed in place of reinforcement. In Steel reinforcement the gapping among bars is 4inch to 6inch while in Post tension slab the gapping is in excess of 2m.

Go through the following video tutorial, to get more details on post tension slab.

Video Source: F&U-FORYOU

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Published By
Rajib Dey
www.constructioncost.co
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Segregation of concrete – Causes and Remedies

Segregation means the partition of course materials (cement, sand, aggregates) from other mass. When the water quantity in the concrete mix is increased, the greater sized aggregates are detached thus results in segregation.

Therefore, concrete should be free from segregation as concrete not only gets weak but lack of consistency also brings unwanted properties in the hardened state. The segregation can be avoided with the choice of proper grading and careful handling.

Reasons for segregation :

Carrying concrete mixes for long distance.

Imperfectly proportioned mix where adequate matrix does not exist to unite the aggregates.

Dropping concrete from height places (underground foundation & rafts).

Vibrating concrete for long time.

Segregation is available in two types - Initially (in too dry mixes), the coarse aggregate is segregated or settling down from the rest of the matrix, secondly ( in too wet mixes ), the paste or matrix is detached away from coarse aggregate. In case of segregation, remixing for a short time may transform concrete again homogeneous.

The following precautions should be taken to get rid of concrete segregation :-

The concrete mix should be perfectly designed with best possible quantity of water i.e. not too wet nor too dry.

The proportion of the mix should be correct.

Ensure the concrete is mixed perfectly at the proper speed in a transit mixture for minimum two minutes.

Concrete should not become excessively wet or dry.

Refrain from arranging concrete from long height.

There should be proper transportation of concrete through shortest route.

Air entraining admixture and pozzolanic materials should be used in mix.

Select coarse and fine aggregate with approach specific gravity.

The vibrator should be used for exact time period (not too long or short).

Don’t permit concrete to flow.

The formwork should be firm.

The formwork should not be vibrated.

Video Source: Civil Engineers

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Rajib Dey
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How to set up formwork in high rise structures

Aluminum formwork is very effective for both high and low-rise concrete construction projects. Aluminum formwork technology can significantly minimize the labor costs as well as makes the project cycles shorter.

WTF aluminum formwork is a highly recognized construction system for building up cast in place concrete structures. WTF offers aluminum formwork for reinforced concrete construction ranging from single and multi-story buildings and facilitates the walls and slab to be positioned monolithically in the similar operation. It enhances efficiency and builds up an extremely robust structure with superb concrete finish.

The WTF Aluminum Formwork System is excellent since it builds all of the components in the structure along with walls, floor slabs, columns, beams, stairs, window details, balconies, and different decorative features with adherence to the architect's design.

WTF aluminum formwork technology is a complete system that can be employed for simple column, beam and slab constructions through to more complicated features like curved structures, staircases, and all architectural features.

Go through the following video tutorial to learn how WTF aluminum form is set up in high rise structure.

Video Source: Civil Engineering

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www.constructioncost.co
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Brief overview of rise and fall table in land surveying

This construction video tutorial is very useful for land surveyor. The tutorial sheds light on the rise and fall table in land surveying. Get some useful tricks to resolve the rise and fall table.

Rise and fall method is applied to resolve the levelling to detect the variation in elevation and elevation of points..


By resolving this table, it is possible to work out the reduced level of each point captured at staff rod with leveling machine. In order to work out the reduced level of an individual point, it is necessary to compute the rise and fall of points. After that, for reduced level, the following formula is applied :-

new R.L = old R.L – Fall
new R.L = old R.L + Rise

The table contains various heads like number, B.S (back sight), I.S (inter sight), F.S (fore sight), Rise, Fall, R.L (reduced level) and remarks.

B.S - Back sight (BS) is the abbreviation for "back sight reading". It means the first staff reading captured by the surveyor as soon as the levelling instrument is arranged and levelled. B.S is normally captured on the point of known reduced level as on the benchmark or a change point. The normally applied datum is mean sea level.

Fore sight (FS) is the abbreviation for "fore sight reading". It means the last staff reading captured prior to modify the instrument to the other position. It refers to the staff reading captured on point whose RL is to be ascertained. This sight is treated as negative and assumed from Height of Instrument to find out RL of the point.

Reduced Level (RL) in surveying stands for equating elevations of survey points relating to a common assumed datum. It refers to a vertical distance among survey point and selected datum plane. Therefore, it is taken as the base elevation that is applied as reference to consider heights or depths of other important places.

To get more detailed information, watch the following video tutorial.

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Rajib Dey

www.constructioncost.co

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