Guidelines for rebar detailing of RCC structures

Reinforcement Detailing or Rebar detailing is a detailed construction engineering process normally accomplished by the Rebar fabricators, structural engineering consultants or the contractors for generating ‘shop/placing’ drawings or shop drawings and bar bending schedule of steel reinforcement for construction. Architect/Engineers(A/E) produce ‘Design Drawings’ with the purpose of adding strengths with rebar size, spacing, location, and lap of steel.

Rebar Detailing is also known as Rebar scheduling, RC Detailing and Bar Bending schedule predation, RC Drafting, etc in different countries.

Objective of Rebar Detailing - The rebar detailing is done for the following purposes :

a) To produce an error-free Bar bending schedule, when fabricated should be accommodated in the concrete formwork devoid of any issue. The similar Bar Bending Schedule should be utilized for accounting and invoicing.

b) To develop a detailed Rebar placing drawing (known as Rebar Shop drawings). This Rebar placing drawing assists an Ironworker to place rebar perfectly in the site efficiently.

c) To allow the structural engineer to verify and approve when the structural design intent is precisely transformed into the Rebar Placing drawings and Bar bending schedules.

d) To perform a Rebar wastage analytics and minimize probable scrap existing in the Drawing level.

Standard Hooks: The term “standard hook” is defined as follow -

1. 180o bend together with an extension of minimum 4 bar diameters, but not below 65 mm at the free end of the bar.
2. 90o bend together with an extension of minimum 12 bar diameters at the free end of the bar.
3. For stirrup and tie anchorage.

For 16 mm φ bar and smaller, a 90o bend along with an extension of minimum 6 bar diameters at the free end of the bar,

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Advantages & Disadvantages of Flat Slab

Normal process of design and construction is to support the slabs with beams and support the beams with column. It is known as beam-slab construction.

The beams help in minimizing the existing net clear ceiling height. Often, in warehouses, offices and public halls, the slabs are used as a substitute of beams and they are directly supported with columns. These types of slabs are known as flat slabs.

A flat slab stands for a one-way or two-way system with solidities in the slab at the columns and load bearing walls are known as ‘drop panels’ Drop panels function as T-beams over the supports. They raise the shear strength and the rigidity of the floor system against vertical loads, thus the economical span range becomes greater.

Normally, the height of drop panels remains about two times the height of slab. The plan dimensions of the drop panels are a minimum of 1/3 of the distance in the direction being considered, normally rounded to the nearest 100 mm.

Flat Slabs are useful for most of the construction and for irregular column layouts like floors having curved shapes and ramps etc.

Types of Flat Slab Construction - Following types of flat slabs are commonly used in construction:

1. Simple flat slab
2. Flat slab with drop panels
3. Flat slab with column heads
4. Flat slab with both drop panels and column heads

The major features of a flat slab floor are a flat soffit, simple formwork and smooth construction. The economical span ‘L’ of a reinforced concrete flat slab is roughly D x 28 for simply supported, D x 32 for an end span and D x 36 for an interior span. Pre-stressing the slab raises the economical span to D x 35, D x 40 and D x 45 respectively, where D stands for the depth of the slab without the drop panel.

Benefits and Drawbacks of Flat Slabs

Benefits:

• Easy formwork
• No beams—streamlining under-floor services outside the drops
• Least structural depth
• Normally, shear reinforcement is not necessary at the columns.
• Saving in the height of the building
• Construction time is reduced
• Application of prefabricated welded mesh

Drawbacks:

• Medium extents
• Normally not ideal for supporting brittle (masonry) partitions
• Drop panels may obstruct with larger mechanical ducting
• Vertical penetrations should circumvent area around columns
• For reinforced flat slabs, deflection at the middle strip becomes important.

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Uses of prestressed concrete in civil engineering

Prestressed concrete is suitable for different types of structural systems which range from pre-tensioned and post-tensioned structures, both cast-in-place and precast, and other pre-stressed components along with normally reinforced concrete.

Pre-stressed and precast concrete is divided in following four major categories:

• Standardized Elements
• Fixed Cross Section Elements
• Fully Engineered Elements
• Precast Nonprestressed Elements

Standardized Precast Prestressed Elements

Pretensioned concrete beams and slabs are normally built up in recyclable steel forms in a precast plant. Though a humble amount of custom formwork is utilized at precast plants, but when standardized components are utilized, the quality becomes better and the costs are decreased.

They comprises of standard sections like single-T and double-T beams, box girders, hollowcore slabs, inverted T-beams, and bridge girders. With the capital investment, it is possible to build up and equip a precast plant with the concrete mixing equipment, forms, stressing beds, curing systems, and heavy lifting equipment.

To increase ROI, the forms and stressing facilities should be applied continually. By improving the production process, the precast pieces can be fabricated on a routine and regular basis.

The cost efficiencies of this type of fabrication allow the architects and engineers to choose the sections for an extensive range of applications and ensure accessibility and competitive cost. Hollowcore planks, single-T, and double-T beams are applied as floor elements in building construction.

Fixed Cross Section Elements

The design engineer takes the responsibility to find out the pre-stressing forces and tendon locations in fixed cross section situations. Two common fixed section design conditions belong to post-tensioned beams and slabs for developing or parking garage construction, and girders for bridge construction.

Other uses of fixed section components range from structures like water tanks and post-tensioned slabs on-ground.

Fully Engineered Elements

For fully engineered elements, there should be constant detailed engineering all through design and construction. Instances of fully engineered structures are segmental bridges, specialty transit structures, tanks, towers, stadiums, floating facilities, and unusual building construction. The design of these structures is based on significant engineering effort as well as on-site inspection.

The intricacy of these structures requires the basic understanding of structural behavior, loads, prestressing effects, and material behavior. Collaboration of efforts among engineers, precast plants, and general contractors is essential.

Precast Nonprestressed Elements

The significant variation in grouping is that pretensioned elements need significant plant capitalization and stressing beds. Precast pieces are fabricated on the jobsite or in a facility devoid of stressing beds and other equipment related to a plant operation. Tilt-up walls are good instances of on-site precasting.

If a small amount of prestressing is necessary for delivery, erection or final loads, it is arranged in the form of single-strand post-tensioned tendons. The instances of precast nonprestressed elements are architectural precast panels and tilt-up construction. Architectural precast panels are utilized either as structural elements or the exterior finish of buildings.

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How to make concrete formwork system safe in the job site

If the safety plans for formwork system remain perfect, construction project will be completed according to approved construction practice and without unnecessary hazards like failure of formwork and consequent delay in construction and possible loss of life. Normally, safety will be commenced in the planning and management of a project.

The safety of workers and the public is mainly dependent on the construction work supervision, equipment deployment practices, and construction method used.

Formwork designers, project planners, and managers should abide by the requirements of relevant standards like OSHA regulation with the purpose of providing good safety planning.

1. Supervision and Inspection: Supervision work should be perfect throughout placing formwork, concrete pouring, and stripping of formworks for maintaining safety in the use of forms.

A supervisor has to take the responsibility for the construction of formwork based on the design and deploying a secure erection method to get rid of overloading of members.

Rectifications of the false work, forms, or erection method in construction site should be performed as per suggestions of the form designer. The application of unusual loads should be controlled when the formwork system is not designed for such loads.

2. Platforms and Access for Workers: There should be proper working platform for the works to be accomplished at elevated positions. Long ladder to the tops of false work should be rest or passing platform. In specific structures like bridges, special scaffolds should be utilized or any other appropriate equipment for the detachment of decks and piers forms.

There should be proper safety signs and barriers to restrict the entry of the unauthorized individuals to the working area throughout erection and striping formwork system. Platforms and access means for worker should be adhered to suitable codes like OSHA requirements.

3. Monitoring Concreting Practices: Controlling concrete pouring plays an important role in formulating the proper safety plan. The sequence and rate of concrete placement should take limitations into account which are provided in the formwork drawings.

At the time of placing concrete, unbalanced form loading should not occur. As for example, in beam and slab construction, initially fill the beams and then work outward uniformly on both sides while setting the slab. The durability of the formwork system is increased in a column-and-slab structure by concreting the columns minimum one day before placing the slab.

Hardened concrete in the columns contributes to extra lateral stiffness to the formwork structure all through the concreting of the slab. Repeatedly, Reinforced concrete column is built up and then erection of floor system is started.

4. Advancement of Soil Bearing and Bracing: Normally, the condition of soil is unidentified while designing the forms and scaffoldings; assumed bearing capacity is applied. Therefore, the contractor should verify whether the bearing strength of the soil at construction site is higher or smaller as compared to the one accepted during design phase. If soil bearing strength is dubious, then it’s stability can be improved by tamping or making a cover with layer of crushed stone. Formworks should be designed to resist gradual collapse caused by localized failures.

5. Shoring and Reshoring: Setting of out of plumb shores, bent jacks, and defective timber should not be done else these supporting elements would support only a small area of design loads. Throughout Concreting, forms should be checked repeatedly to detect problems and instantly rectify them.

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Some important checklists for RCC slab and beams

The following checklists are extensively utilized for RCC slab and Beams.

1. Examine the bottom line, level & width of beam properly.
2. Examine the side line, level & plumb of beam properly.
3. Beam to beam measurements should be examined according to architectural drawings.
4. Individual level & diagonal of each slab bay should be examined properly.

5. The thickness level of slab should be marked with nails on the peripheral beam’s exterior sides.
6. Examine the thickness of slab and depths of beam properly.
7. Support props for slab & beam bottoms should arrange in line & plumb. Bamboo bracing should be accomplished at around 4′ ht from floor level. Support props for double staging terraces should be examined cautiously.
8. Line of external /peripheral beam’s sides should be examined & cross supported to get rid of buldging out of sides.
9. Junctions of columns & beam should be verified to make them water resistant.
10. De-shuttering oil should be provided to beam/slab shuttering.

11. Formwork of stair case should be examined for dimensions of tread and riser, level of treads, plumb of risers.
12. Reinforcement should be examined for beams and slab as per R.C.C drawing
13. Ensure to provide exact cover for bottom /sides of beams.
14. Proper cover should be provided for slab.
15. Electrical points, electrical piping (conduits)/fan hooks should be examined as per drawing.
16. Reduction of column according to drawing should be performed if any.
17. There should be exact numbers of chairs should be arranged for slab.
18. Dowels (if any) should be arranged for elevational feaures / future expansion.
19. Parapet (Pardi) bars should be provided for balconies/staircase etc.

20. Ring (stirrups) should be arranged at the free end of each column reinforcement.
21. Distances among plates /planks should be filled. Taping should be performed at ply joints for the protection of ply shuttering.
22. Before starting pouring work, consent of the architect and R.C.C Consultant should be obtained.
23. Prior to start concreting work, verify the accessibility of necessary labour strength, mixer, lift, vibrators, masons, weigh batcher, diesel/petrol and plastic sheets etc before start of concreting.
24. Hidden beams /inverted beams/cantilever beams should be examined properly.
25. Based on the approved drawings, verify the sunk.
26. Packing underneath support props should not be provided. As an alternative, single wooden plank should be inserted as packing.
27. For large slabs, exact location of concrete joints should be determined beforehand as per approval of RCC consultant.
28. Accessibility of raw material for concrete /RMC per grade of concrete, water , electricity should be examined beforehand prior to start concreting work.

29. Initially, concreting should be performed for the beams & then slabs.
30. Compaction of concrete should be accomplished with vibrators & tamping rods.
31. The top level of the slab should be completed with mason & there should be restrictions to walk on the fresh finished concrete.
32. Carpenter should be provided under the slab shuttering throughout concreting to keep the form work tight.
33. For protection against rains, large plastic sheets should be used to wrap finished concrete.
34. Cast 6 cube moulds for testing.
35. Curing of slab should be accomplished with ponding method by making ponds in cement & sand mortar (1:10) of size around 5′ X 5′. Curing of beams and slabs should be performed for 7 to 10 days or as suggested by the consultant.
36. Deshuttering of the exterior sides of the beam should be accomplished after 24 hours . Deshuttering of the inner sides of beam should be accomplished after 48 hours . Deshuttering of the beam bottoms should be accomplished after 14 days for beam lengths up to 3 M or as per suggestions of the consultant. Deshuttering of the slab should be performed after 7 days for slabs up to 3 M span or as directed by the consultant.
37. Finishing of honeycomb should be accomplished cautiously in front of engineer the next day.
38. Hacking of the beam sides, beam bottoms, slab bottoms should be accomplished within 1 or 2 days from deshuttering.
39. Date of casting and the number of slab should be painted on the front side beam.

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Details about Composite Slabs & Columns and their benefits

Composite slabs:

1. It comprises of profiled steel decking with an in-situ reinforced concrete topping.
2. The decking(profiled steel sheeting) perform as permanent formwork to the concrete as well as offers adequate shear bond with the concrete in order that when the concrete has attained strength, the two materials function mutually & compositely.

3. Distance among 3 m and 4.5 m onto supporting beams or walls.
4. When the slab is unpropped throughout construction, the decking single-handedly withstands the self-weight of the wet concrete and construction loads. Subsequent loads are delivered to the composite section.
5. When the slab is propped, all of the loads should be combated by the composite section.
6. These are normally designed as simply supported members in the normal condition.

Profiled steel sheeting:

1. Depths vary from 45 mm to over 200 mm.
2. Yield strengths vary from 235 N/mm2 to minimum 460 N/mm2.
3. The thickness vary from 0.8 mm to 1.5 mm.
4. The different shapes offer Interlock among the steel and concrete.
5. Decking is also applied to make the beams stable against lateral torsional buckling throughout construction.
6. Improve the stability of the building entirely by behaving as a diaphragm to transmits the wind loads to the walls and columns.
7. Temporary construction load normally manages the choice of decking profile.

Composite Columns:

A steel-concrete composite column stands for a compression member that contains either a concrete encased hot-rolled steel section or a concrete filled tubular section of hot-rolled steel. The existence of the concrete is granted for two ways.

1. Safeguard from fire.
2. It may also withstand a small axial load.
3. To minimize the effective slenderness of the steel member, that raises its resistance capacity against axial load.

The bending stiffness of steel columns of H-or I-section is superior in the plane of the web (‘major-axis bending’) as compared to a plane parallel to the flanges (‘minor-axis bending’).

The ductility performance of circular type of columns is considerably superior as compared to rectangular types. There is no need to offer extra reinforcing steel for composite concrete filled tubular sections.

Protection from erosion is arranged by concrete to steel sections in encased columns.

When the local buckling of the steel sections is removed, the reduction in the compression resistance of the composite column caused by overall buckling should definitely be permitted. The plastic compression resistance of a composite cross-section shows the maximum load that can be employed to a short composite column.

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Points to be considered prior to concreting ground beams and plinth beams

Prior to start concreting work for ground beams & plinth beams, proper examination should be carried out in the following two phases :-

Initially, test out formwork prior to arrange or bind reinforcement. It is important since specific formwork errors can’t be rectified or it becomes complicated to repair once the reinforcement is arranged in position.

Checking reinforcement.

01. Centering and shuttering / Formwork:

• P.C.C. of proper grade and thickness (least 50 mm and M5 or 1: 4:8 grade) should be provided prior to apply shuttering for ground beam and it should be perfectly leveled and remains in exact line.

• The P.C.C. should be expanded minimum 50 mm exceeding the width of beam on both faces. Verify all the level of ground beams.

It should be minimum 150 mm in natural ground, in order that the earth filled inside walls or a beam doesn’t get out throughout plinth filling. Also check that all ground beams are located on equivalent level.

• Verify that all the soil on which beam is placed is correctly compacted (specifically for freshly excavated foundation pits) so that the ground beam never sags throughout curing or watering due to settlement of loose soil.

• The bricks should not be used since it can’t retain exact level and line.

• Start formwork for ground beams or plinth beams after filling because providing props may lead to delay since time is required for detaching props and filling work can be resumed during that period causing delay of slab.

• Prior to apply mould release agent, the shuttering should be dry and shall be cleansed properly. During shuttering work, the similar type of release agent should be used for same shuttering materials.

• The surface of shuttering should be level and thin coating should be provided with mould release agent.

• The mould release agent should not get in touch with reinforcement or the solidified concrete.

• Shuttering should be set in such a way that the joints are sealed properly to resist leakage of cement slurry.

• Prior to binding or placing reinforcement, the size of beam should be examined properly.

• Make sure that the meeting point of beam & column is tight and no bulging should occur throughout concreting.

• Take out all the debris like dust, paper, leaves, chippings of woods, nails, reinforcement wastage, soil particles etc.

02. Reinforcement:

• Prior to set the concrete, verify the reinforcement details as per bar bending schedule and obtain the approval of structural consultant.
• The reinforcement of beam should remain in exact alignment. If extent of beam exceeds 6 to 9 meter than camber should be arranged according to drawing.
• Examine the laps of beam with detailed drawing. There should not be laps in middle of beams if they contain long span. The lap should be maintained at various positions at few different bars.
• Verify the joints details according to detailed drawing- flexible or rigid.
• Bent up bars should be provided based on detailed drawing.
• Verify whenever the reinforcement of cantilever beam remains in top doubly anchored.
• Also examine the counter balance of cantilever beam.
• Stirrups should be placed at the intersection of beams and columns and in most cases it is generally overlooked.

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Different types of vibrators generally found for concrete compaction

The objective of a vibrator is to compact concrete on the construction site easily and efficiently. At the time of vibration, compacting is influenced by cutback in internal friction among different particles of concrete because of oscillation of particles which lead to a solid and compact mass of concrete.

Vibrations can be accomplished in the following ways :-

a. Provided in the interior of the concrete with Internal vibrator, or
b. Provided in concrete by vibrating formwork with Shutter form vibrators, or
c. Provided on the surface of concrete with Surface vibrators, or
d. Provided in the total concrete mass with Vibrating table.

The following types of vibrators are generally found for compaction :-

1. Internal or Immersion or Poker or Needle Type Vibrator
2. Shutter form or External Type Vibrator
3. Surface or Screed or Pan Type Vibrators
4. Vibrating Tables

1. Internal Vibrators: These are also known as immersion, poker or needle vibrators. They basically comprise of a power unit and a long adjustable tube, at the end of which a vibrating head is connected. Power is supplied through electric motor, compressed air or petrol engine. The long tube comprises of a flexible shaft that revolves an eccentric weight inside the vibrating head. The frequency of the vibrator remains approximately 700 cycles per minute.

The vibrating head is included in the concrete. They are very useful since the vibrating head gets in touch with concrete closely.

2. Form Vibrators: They are also known as external vibrators. They are secured with the formwork horizontally and vertically at exact distance not surpassing 90 cm in either direction.

With the advancement of the work progress they are transferred. They vibrate the concrete from the vibration of the forms and consequently lots of energy is exhausted.

Form vibrators will be applicable when the internal vibrators can’t be used in the case of thin and congested sections, arches and tunnel lining, etc.

3. Surface Vibrators: They are also known as screed or pan vibrators. They are secured to the screed. They vibrate the concrete from the surface while screeding (striking off) of the concrete is performed. They are useful when the depth of concrete remains up to 20 cm.

In case the depth is higher they should be utilized along with internal vibrators. They are suitable for long horizontal surfaces like pavements and slabs.

4. Vibrating Tables: These are inflexible and constructed with steel platforms secured on steel springs and operated by electric motors. The concrete is provided in moulds mounted on the platforms and firmly secured to the vibrating table, to facilitate mould and concrete vibration conjointly.

Vibrating tables are utilized for compacting hard and rough mixes utilized in precast structural members in factories and laboratory samples.

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Steps involved in cement concrete works

Given below, brief specifications for executing cement concrete works for different objectives :-

1. Materials for Cement Concrete: Different types of materials cement, aggregates and water are required for cement concrete works. The aggregates are categorized as fine aggregates (sand) and coarse aggregates. The aggregates should comprise of inert material and should be clean, dense, hard, robust, long-lasting, non-absorbent. Besides, it should have the ability to make superior bond with the cement mortar.

Cement - Fresh Portland cement or pozzolana Portland cement (PPC) should be used according to requirement or specification and should contain the necessary tensile and compressive strength and fineness.

Fine Aggregates - Course sand with hard, sharp and angular grains should be utilized as fine aggregate or sand and it should get through 5mm (3/16”) square sieves or mesh. It should contain standard quality and does not contain dust, dirt and organic matters. Sea sand is not recommended for concrete works. Fine aggregates should comprise of crushed stone or manufactured sand if indicated.

Coarse Aggregates - These should comprise of hard broken stone of granite or similar stone and does not contain dust, durst and other foreign materials. The size of stone ballast should remain 20mm (0.75 inches) and less and should be arranged on 5mm (0.25 inch) square mesh. These should be well grades to retain voids under 42%.

The size of coarse aggregate is based on the thickness of concrete and nature of work. As for instance, size of coarse aggregates for building works should remain 20mm and 40mm to 60mm sizes are applied for road work and mass concrete works.

Water - The quality of water should be same as drinking water and it does not contain alkaline and acid matters.

2. Proportioning of Cement Concrete: The proportions in cement concrete should be according to the design and strength requirements. The proportion can be 1:2:4 (M15 concrete) or 1:1.5:3 for M20 concrete. The proportions of 1:2:4 concrete include the ratio of cement: sand: coarse aggregates by volume until indicated. Least compressive strength of concrete of 1:2:4 mix proportion should be 140 kg/sq.cm or 2000 lbs/sq.in on 7 days.

3. Measurement of Materials: Sand and coarse aggregates are calculated by volume with boxes. Cement should not be calculated by box, one bad of cement of 50kg weight should be treated as 1/30 cu.m or 1.2 cu.ft volume. Size of measured boxes may be 30 cm x 30 cm x 38 cm or 35 cm x 35 cm x 28 cm similar to the content of one bag of cement.

All materials should be dry and in case of utilizing damp sand, compensation should be done with extra quantity sand to the extent necessary for bulking of sand.

4. Mixing of Cement Concrete: Mixing of concrete should be done with machine to attain superior quality. For small works, hand mixing by batches is suitable.

5. Checking for Concrete Slump: Slump test should be conducted constantly to control the addition of water and to retain the desired consistency. A slump of 7.5cm to 10 cm (3 inches to 4 inches) is perfect for building work and 4 cm to 3 cm (1.5 inch to 2 inches) is ideal for road work.

6. Formwork for Concrete Works: Formwork centering and shuttering should be arranged as per need and the standard specifications prior to place concrete to confine or to support or to retain the concrete in exact location. The inside surface of the concrete should be oiled with formwork oils so that the concrete can’t stick to it.

Before placing concrete, water should be sprinkled over the base and formwork where the concrete will be arranged. Forms should not be detached prior to 14 days in general, side forms may however be detached after 3 days of concreting.

7. Placing of Concrete: It is necessary to place concrete gently in layers not surpassing 15cm or 6 inches and it should be consolidated by pinning with rods and tamping with wooden tampers or with mechanical concrete vibrating machines unless a solid concrete is produced.

Concrete should be placed constantly. If the placing of concrete is postponed for rest of the day or for the following day, the end should be sloped at an angle of 30 degrees and made rough for jointing again.

Curing of Concrete: After about two hours of placing when the concrete starts to become solid gradually, it should be retained moist by covering with wet gunny bags or wet sand for 24 hours and then curing by flooding with water making mud walls of 7.5 cm or 3 inches high or by covering with wet sand or earth and kept damp constantly for 15 days.



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Simple process to calculate shuttering materials for footing

There are various types of formwork materials can be used for footings. You can use plywood, wooden plank or even steel shutter.

Mostly used shutter materials for footing is wooden planks, plywood or wooden board as those are cheap and widely available.

How to Easily Estimate Shuttering Materials for Footing

There are different types of footings in a building. But, all the footings are different. There should be equivalent types of footings. Initially, it is required to summarize the similar type of footings.

Summarizing footings - Generally, the footings are demarcated as F1, F2, F3… etc.

Presume, there are 10 numbers of F1 type footing, 6 numbers of F2 type footing, and 8 numbers of F3 type footing, etc.

Summarize them all. The same types of footings will be summarized based on the footing layout drawing sheet. It is accessible in the structural drawing book.

Once the counting is done for all types of footings, verify the footing layout drawing to find out whether any footing remains unmarked. If there is any, count it also.

Once this step is completed, you’ll get the numbers of all types of footing.

Now, the total number of footings should be counted in the footing layout drawing by marking individually with the pencil.

It is not necessary, to create formwork for all the footings. As for instance, there are 10 numbers of F1 type footings. The sizes of all these footing are equivalent. If you only create one formwork for this type, that can be used again for all 10 footings. In this way, the cost will be saved significantly.

To reduce the cost, it is recommended to utilize wooden shutter materials for footing instead of steel shutter for footings.

Given below, the detail method to measure wooden shutters materials for the footing of a building project.

Step 1: Work out the Periphery Length of Footing.

Assume, the size of the F1 footing is, 4′ x 6′ x 1′.
Therefore, the periphery length of this footing will be as follow :-
= (4′+6′) x 2
= 20′
Step 2: Work out The Periphery Area of The Footing
The periphery area of the F1 footing is,

=20′ x 1′ (the height of the footing is taken as 1′)
= 20 square feet (sft)

Step 3: Workout Shuttering Materials

Wooden plank or plywood : The periphery area of the F1 footing is actually required area of wooden plank or plywood that is 20 square feet. It is required to include 5% extra while giving order for wooden plank or plywood. Therefore, necessary wooden plank or plywood for our footing is, 21 sft.

Wooden batten: Usually, 3″x 2″ wooden batten for the formwork of footings is utilized. To make the process simple for calculating wooden batten, just use a thumb rule that is 2 rft (running feet) per shuttering area. So, required wooden batten for the footing will be as follow :-

= 2 x 21
= 42 rft (running feet)

Nail: Similarly, to calculate nail for formwork, just use a thumb rule that is 0.02 kg for one square foot of shuttering area.

Therefore, the required nail for our example footing is,
=0.02 x 21
=0.42 kg (kilogram).

So, the necessary shuttering materials for one formwork of F1 type footing are obtained. Depending on how many formworks will be required for F1 type footing, multiply the shuttering materials with that number.

As for instance, if there are 10 numbers of F1 type footing and it is necessary to create 3 numbers of formwork for this type footing, required shuttering materials for 3 numbers of formwork for F1 type footings will be as follow:-

• Wooden plank or plywood = 3 x 21 = 63 sft
• Wooden batten (3″x2″) = 3 x 42 = 126 rft
• Nail = 0.42 x 3 = 1.26 kg.

In the same way, work out the shuttering materials for all several types of footing for your building project and summarize them all.



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