As civil engineers, it is our job to plan, construct, and maintain the infrastructure that allows our communities to function. We work on everything, including water treatment facilities, airports, roads, and bridges. Every site engineer should be familiar with a certain set of fundamental concepts, Civil Engineering Basic Knowledge and Practical construction knowledge to succeed in this industry.

Get started with the fundamentals of civil engineering basics and practical. This blog post provides an overview of the essential concepts, principles, and applications that form the backbone of the discipline. Learn about structures, materials, surveying, and about the Basic Knowledge of Civil Engineering in this comprehensive guide.

Civil Engineer Practical Knowledge

As a Civil Engineer, there is some fundamental practical knowledge that you should be aware of. Let’s go through each one of them to ensure that you have a clear understanding:

1. The weight of a first-class brick should not be less than 3.85 kg.
2. The first-class brick’s tensile strength shouldn’t be less than 3000 lbs/per square inch.
3. A hook should have a minimum length of 9D.
4. Water should not make up more than 1/5 or 1/6 of the weight of a first-class brick.
5. A common building height should be 315 centimeters tall.
6. The riser should typically be 15 centimeters tall.
7. The recommended lintel thickness is 15 centimeters.
8. The FM limit for normal and local sand should be 0.5 to 0.8.
9. The recommended window height is 120 centimeters.
10. The DBC should have a minimum thickness of 2.5 centimeters.
11. so, above is the basic Civil Engineer Practical Knowledge.

Basic Knowledge of Civil Engineering in Building Construction

Aspiring builders and architects must have a clear understanding of building construction principles to ensure that their projects meet safety standards and are structurally sound. Here are some important factors to consider:

1. The cantilever anchorage length for the main steel should be at least 69 times the diameter of the bar (69D).
2. The bend length for a column should be a minimum of 300mm.
3. For chairs, the minimum diameter of the bar should be 12mm.
4. The minimum diameter of a dowel bar should also be 12mm.
5. Lapping lengths should not be used for bars larger than 36mm.
6. For square columns, a minimum of 4 bars is required, and for circular columns, a minimum of 6 bars is required.
7. The amount of longitudinal reinforcement should not be less than 0.8% or more than 6% of the gross cross-section.
8. The main bar in a slab should not be less than 8mm (if it is HYSD) or 10mm (if it is a plain bar), and the distribution bar should not be less than 8mm and not more than 1/8 of the slab’s thickness.
9. All reinforcement must be free from mill scales, loose rust, courts of paint or oil, and any other substances.

Site Engineer Basic Knowledge of Construction Site

As a construction professional or site engineer, it is important to have a basic knowledge of the terminologies and standards used in the industry. Here are some key points to remember:

1. Dead Load refers to the weight of a structure itself, without any external forces acting upon it.
2. Damp Proof Course (DPC) is a layer of waterproof material, usually at least 2.5cm thick, that is placed between a building’s foundation and the first layer of bricks or blocks to prevent moisture from entering the structure.
3. Sand with a moisture content greater than 5% is not suitable for use in the concrete mix, as it can adversely affect the quality and strength of the final product.
4. The curing period for Reinforced Cement Concrete (RCC) is 28 days, which is the amount of time needed for the concrete to gain sufficient strength and durability.
5. Ties are the transverse reinforcements provided in columns to help resist lateral forces, while stirrups are the transverse reinforcements provided in beams to help resist shear forces.
6. In beams, stirrups are provided to prevent the longitudinal bars from buckling and to help resist shear forces.
7. The purpose of providing ties in columns and stirrups in beams is to handle the shear force and keep the longitudinal bars in position.
8. M20 grade of concrete is commonly used in the construction of slabs, which is a mix of cement, sand, and coarse aggregates in the ratio of 1:1.5:3.
9. The minimum length of the hook provided at the end of a reinforcing bar should be 9 times the diameter of the bar (9D).
10. The unit weight of Plain Cement Concrete (PCC) is 24 KN/m², while that of RCC is 25 KN/m². The unit weight of steel is 7850 Kg/m².
11. Cement that is more than 3 months old is not recommended for use in construction, as it may have lost its strength and could adversely affect the quality of the final product.
12. The standard size of a brick is 19cm x 9cm x 4cm, and it is commonly used as a building material.

Basic Building Planning:

Civil Engineering Basics – Useful Tips for Civil Engineers

Percentage of Waste Factor in Different Building Materials:

Construction Materials

Cement: Cement is produced by crushing limestone and clay gravel. It acts as a binder, facilitating the cohesion of cement, sand, and water. There are several important types of cement.

Aggregate: There are two main types of aggregate:

1. Fine Aggregate: Fine aggregate consists of materials that pass through a 4.75 mm sieve and are retained on a 0.075 mm sieve. An example of fine aggregate is sand.
2. Coarse Aggregate: Coarse aggregate is the material that is retained on a 4.75 mm sieve. Gravel is an example of coarse aggregate.

Concrete: Concrete is formed by combining cement, aggregate, and water according to a specific mix. The water-to-cement ratio plays a crucial role in determining the strength of the concrete, with a higher ratio resulting in weaker concrete.

The strength of concrete is indicated by a term such as M-25, where “M” stands for mix and “25” represents the compression strength at 28 days, measured using concrete cubes of 15 cm on each side.

Concrete has two types of setting:

1. Initial Setting Time: The initial setting time is approximately 30 minutes, during which the concrete begins to solidify.
2. Final Setting Time: The final setting time is around 10 hours, marking the completion of the concrete’s setting process.

The setting time of concrete is determined using a Vicat apparatus.

With the aid of admixtures, concrete setting time can be modified based on environmental factors. Retarders and accelerators are terms used to describe mixtures that affect how quickly the setting time passes.

Components of Building:

Minimum Design Requirements for Staircase Construction:

Staircase construction is an important aspect of building design and requires careful consideration to ensure safety and functionality. Here are the minimum design requirements for staircase construction:

1. Headroom: There should be a minimum of 2 meters of headroom above each tread and beneath the landing.
2. Stair width: The staircase should have a minimum clear width of 900mm.
3. Handrails: There must be handrails on both sides of the staircase, and they must be between 900 and 1100 millimeters above the tread.
4. Riser: The rise in stairs, which is the height between two consecutive steps, should be between 150mm to 200mm.
5. Tread: The tread in the staircase, which is the horizontal depth of each step, should be between 250mm to 300mm.
6. Slope or Pitch: The slope or pitch of the staircase should be between 25 degrees to 40 degrees.
7. Balustrades: Guardrails or balustrades must be installed along the open sides of the staircase, and they must be at least 900mm in height.
8. Lighting: The staircase and landings should have sufficient lighting, with switches placed at the top and bottom of the staircase.
9. Non-Slip Surface: Each tread should have a non-slip surface to reduce the risk of accidents.
10. Structural Support: The staircase must be built to offer sufficient structural strength for the intended load and use.

11. Fire Safety: Staircases must be built by all applicable fire safety regulations, including the provision of materials that are fire-resistant and a suitable means of escape.

Thumb Rule for Manpower Productivity Estimation:

Strengthening Techniques for RC Columns:

Concrete Slump Value for Various Concrete Constructions

Grades of Concrete:

Clear Cover to Main Reinforcement:

Unit Weight of Different Building Materials

Development Length

In Compression	38 diameter
In Tension	47 and 60 diameter

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Concrete Mixes and Purpose:

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Curing Method of Concrete:

Enlist below are various techniques used for the curing of concrete:

• spraying
• ponding
• steam curing
• wet covering
• curing chemicals

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Different Types of Columns:

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Cube Samples for Different Quantity of Concrete Volume:

Using cube samples that accurately reflect the concrete’s volume is essential when evaluating the compressive strength of the material. The quantity of cube samples needed to ensure accurate measurements varies depending on the amount of concrete being tested. The suggested cube sample sizes for various concrete volumes are listed below:

S. No	Volume of Concrete	Number of samples
1	from 1 to 5 m3	1 sample
2	from 6 to 15 m3	2 samples
3	from 16 to 30 m3	3 samples
4	from 30 to 50 m3	4 samples
5	50 plus or above 50 m3	5 samples

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Weight of Steel Bar per M/Kg:

The weight of the steel (reinforcement) bar in meters per kilogram is given in the table below:

S. No	Dia of the bar in (mm)	Weight of steel in Kg per meter
1	6	0.22
2	8	0.39
3	10	0.61
4	12	0.88
5	16	1.57
6	20	2.46
7	25	3.85
8	32	6.31
9	40	9.86

Note:

The formula is used in this table is D²/162.162 in Kg/m. this formula is used when the dia of bar (reinforcement) is in mm and the length of the bar is in meters.

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Removal of Formwork or De-Shuttering Time:

There are different members of formwork such as foundation, column, beam and slabs, etc. after poring of concrete the shuttering should be removed after some time the time of de shuttering is given below:

S. No	Members of structure	Days
1	for Sides of foundation, beam, columns and walls	2 days
2	for Sides of slab under 4.5 meter span	7 days
3	for Sides of slab above 4.5 meter span	14 days
4	for Side of beams and arches up to 6 meter span	14 days
5	for Side of beams between 6 meter to 9 meter span	21 days
6	for Side of beams and arches above 9 met	28 days

 

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Load Types on Beam:

Thumb Rule for Steel in RCC:

The post Civil Engineering Basic Knowledge – Every Engineer Must Know appeared first on The Civil Engineering.

If you are planning a building project, it’s important to get an accurate estimate of how much the compound wall will cost. Using bar bending schedule to plan is a useful tool that not only helps with budgeting, but also enables you to have better control over your project. Its also help to prepare estimating and costing of earthwork excavation and block masonry construction cost of wall.

What is Compound Wall?

A compound wall for a building is a wall that surrounds the outside of a building or collection of buildings, like an apartment building or a campus of office buildings. It acts as a boundary between private property from public areas.

Its major function is to define the boundaries of the property and to give residents privacy and security. Depending on the level of security necessary, compound walls can be constructed from a variety of materials, including concrete, brick, stone, or wood. They can also vary in height and thickness.

Estimate of Compound Wall:

Let’s now calculate the price of a compound wall for a 40′ × 50′ site with a 10 ft gate as shown below:

Estimating and Costing of Compound Wall:

We have provided the RCC columns at 10 ft. c/c.

The No. of columns required

= site perimeter ÷ c /c column’s distance

= [ ( 50 ft.× 2 nos.) + ( 40 ft. × 2 nos.)] ÷ 10 ft.

= 180 ft ÷ 10 ft.

= 18 nos. ( as shown below.)

1. Earthwork Excavation for Compound Wall:

Excavation for the footing:

The number of excavation pit required for the rcc column footing = 18 nos.

Let us provide  1.5 ft × 1.5 ft size footings, and the dimension of the pit to accommodate these footings shall be  2ft. × 2ft.× 2.5 ft. as shown in the drawing below.

The total volume of excavation for footing = Volume of Single Footing x Nos of Footings

= (2′ × 2′ × 2.5′) × 18 nos.

= 180 cft.

Excavation for the plinth beam:

Let us excavate 4″ (inch) extra on both side of the plinth beam for formwork removal as shown in the drawing.

The volume of excavation for the plinth beam (RCC)

= [ perimeter of site  – ( No. of footings × footing excavation width.)] × plinth excavation width × plinth excavation depth

= [180 ft. – (18 nos. × 2 ft.)] × 1.416 ft. × 0.9166 ft.

=  144 ft. × 1.416 ft. × 0.9166 ft.

=  186.90 cft.

The total excavation of earthwork for compound wall

= footing excavation + plinth excavation

= 180 cu ft + 186.90 cu ft.

=  366.90 cft.

2. Boulder Soling for Compound Wall:

Let us make a boulder soling of 9″ (inch) thick ( 0.75 ft.) for the footing as shown below.

The volume of soling for the footing = Volume of Soling per footing x No. of footings

= ( 2 x 2 x 0.75) × 18 Nos

= 3 cft × 18 Nos.

= 54 cft.

3. PCC for Compound Wall:

Let us prepare 4 inch thick ( 0.33 ft.) PCC bed for the footing & plinth beam.

volume of PCC for the footings:

The volume of PCC for the footings = Volume of PCC per footing x Nos of Footings

Vp1 = ( 2 ft x 2 ft x 0.33 ft) × 18 cft.

= 1.32 cft × 18 Nos.

= 23.76 cft.

As we know that the volume of excavation for the plinth beam is 186.90 cu ft.

From the above drawing, depth of excavation = 0.9166 ft.

PCC thickness = 4″ ( 0.33ft.).

Volume of PCC for the plinth beam

Volume of PCC for the plinth beam = X-Sec Area of PCC under Beam x [Beam Parameter – (Width of footing x Nos of Footings)]

Vp2 = (1.416 x 0.33) x [ 180 ft – ( 1.5 ft x 18 Nos)]

= 0.47 sft × 153 ft

= 71.91 cft.

The total volume of the PCC for the compound wall

= Vp1 + Vp2

= 23.76 cft.+ 71.91 cft.

= 95.67 cu ft.

Calculating the quantity of materials in PCC.

Let us make PCC (Plain Cement Conc.) in the 1:2:4 mix.

Quantity of cement bags required for PCC (Plain Cement Conc.)

= 17.942 bags × ( 95.67 cft ÷ 100 cu ft.)

=  17.16 bags.

The volume of sand required for PCC

= 44 cu ft. × ( 95.67 cft ÷ 100 cft.)

=  42.09 cft.

The volume of aggregates required for PCC

= 88 cu ft. × ( 95.67 cft ÷ 100 cft.)

= 84.19 cft.

4. Quantity of Materials in RCC Footings:

Let us make a RCC footing of size 1.5 ft × 1.5 ft. having 10″ ( 0.833 ft. ) thickness as shown in the drawing

Given data :

Footing length = 1.5 ft.

Width = 1.5 ft.

Thickness = 0.833 ft.

Rebar diameter = 10 mm.(0.0328 ft.),

Spacing = 5″ (0.416 ft. ) c/c

Cover = 2″ (0.166 ft ) on all the sides.

As we know that, the number of footings = 14nos.

4a. The volume of footing for the compound wall

= [total nos. × length × breadth × thickness]

= [18 nos. × 1.5 ft. × 1.5 ft. × 0.833 ft.]

= 33.74 cu ft. i.e. 0.95 cum. 

4b. BBS for the footings:

No. of bars along the x-axis

= [ {( footing length ) – ( 2 × cover )} ÷ spacing ] + 1

= [ {( 1.5 ft.) – ( 2 ×0.166 ft.)} ÷ 0.416 ft.] +1

= [ { 1.168 ft. } ÷ 0.416 ft. ] +1

= 2.807 +1

= 4 nos.

( By rounding off )

No. of bars along the y-axis

= [ {( footing width ) – ( 2 × cover )} ÷ spacing ] + 1

= [ {( 1.5 ft.) – ( 2 ×0.166 ft.)} ÷ 0.416 ft.] +1

= [ { 1.168 ft. } ÷ 0.416 ft. ] +1

= 2.807 +1

= 4 nos.

( By rounding off )

Cutting length of the bar along the x-axis

=  [ {bar length in x-axis } + { 2 nos. × ( L – bend length)}] – 2nos. × ( 2 times bar dia. for 90° bend.)

( we have deducted 2 times bar dia i.e. 2d for the  90° bend of the bar. )

= [ { footing length – 2 × cover } + 2nos.×{ footing height – 2 × cover}] – 2× ( 2 × bar dia. )

= [ { 1.5 ft. – 2 × 0.166 ft. } + 2 × { 0.833 ft. – 2 × 0.166 ft. } ] – 2 × ( 2 × 0.0328 ft.)

= [ 1.168 ft. + 1.002 ft. ] – 0.131ft.

= 2.17 ft. – 0.131 ft.

= 2.039 ft. i.e. 0.6214 m.

Cutting length of the bar along the y -axis

=  [ {bar length in y-axis } + { 2 nos. × ( L- bend length)}] – 2nos. × ( 2 times bar dia. for 90° bend.)

= [ { footing width – 2 × cover } + 2nos. × { footing height – 2 × cover}] – 2× ( 2 × bar dia. )

= [ { 1.5 ft. – 2 × 0.166 ft. } + 2 × { 0.833 ft. – 2 × 0.166 ft. } ] – 2 × ( 2 × 0.0328 ft.)

= [ 1.168 ft. + 1.002 ft. ] – 0.131ft.

= 2.17 ft. – 0.131 ft.

= 2.039 ft. i.e. 0.6214 m.

Note: The cutting length & number of bars in both ( x-axis & y-axis ) directions will be the same, in the case of square footing having a similar bar diameter.

Now, we will prepare BBS (Bar Bending Schedule) of the footing, from calculated data.

sl       bar      dia.   no.   length      total     weight         total     

no.    type    mm.            in m.    length    in kg/m       weight

1.    x- axis    10    4    0.6214     2.4856      0.62         1.54

2.    y – axis    10      4      0.6214     2.4856      0.62          1.54

Total weight of the bars = 3.08 kgs

Add 2 % wastage            = 0.0616 kgs

A grand total of rebar for a footing    =   3.1416 kgs.

Note : Weight of 10mm dia bar /meter is 0.62 kg.

The total weight of the 10mm dia bar for all the footings

= [18 nos. × 3.1416 kgs.]

= 56.55 kgs.

5. Quantity of Materials in RCC Plinth Beam:

Let us make a 9″×12″ RCC plinth beam as shown in the drawing.

Given data :

Plinth beam size = 9″× 12″

Main bar dia = 12 mm.,   no. of bars = 4 nos.

Stirrups  8mm @ spacing 150mm c/c , clear cover = 25 mm from all the sides.

5a. The volume of plinth beam concrete

= length × breadth × depth

= [ (perimeter of site – no.of columns × column width) × breadth × depth]

= [(180 ft – 18 nos. × 0.75 ft.) × 0.75 ft × 1 ft.]

= [166.5 ft. × 0.75 ft. × 1ft.]

= 124.875 cu ft. i.e. 3.53 cum.

Note: We have deducted the column width from the plinth beam length, as we have included them in the column volume.

5b. BBS of plinth beam for the compound wall.

The perimeter of site = 180 ft. = 54864 mm.

We will provide Ld at the corner rcc columns of the compound wall, passing the plinth bar through the intermediate columns.

The cutting length of the main bar 

= [ (perimeter of site) + (8 nos × Ld ) + (4 nos. × lap length) – (8nos × column width) ]

Note: we assume that one overlapping for each bar & we will provide a lap length of 50d.

Let us provide development length Ld = 40d for the main bar.

= [ (54864 mm.) + (8 nos. × 40 × 12mm) + (4 nos × 50 × 12 mm) – (8 nos.× 230mm)]

= [54864 mm + 3840mm + 2400mm – 1840mm ]

= 59264 mm. i.e. 59.264 m.

Cutting length of the stirrup

= 2 nos. × (a +b ) + hook length – 90° bend – 135° bend

Where a = beam width – 2 × cover, & b = beam depth – 2 × cover

= 2 nos.  × [ ( 230 mm – 2 × 25mm.) + ( 300 mm – 2  × 25mm ) ] + (10d ) – (3 nos. × 2d ) – (2 nos. × 3d)

Here, 10d is taken for hook length.

We have deducted 2d for 90° bend – 3nos., & 3d for 135° bend – 2nos. as shown in the above drawing.

= 2 nos. × [ ( 180 mm ) + ( 250 mm ) ] + (10 × 8mm) – ( 3 nos. × 2 × 8mm ) – ( 2 nos. × 3 × 8 mm.)

= 2 nos. × [ 430 mm ] + 80 mm – 48mm – 48mm.

= 860 mm + 80 mm – 96 mm.

= 844 mm i.e. 0.844 m.

Number of stirrups 

= ( length of the plinth beam ÷ stirrup spacing ) + 1

where Length of Beam = Parameter – (0.75 x No. of footings) = 180 – (0.75 x 18)

here, length of the plinth beam = 166.5 ft = 50749 mm

= ( 50749 mm. ÷ 150 mm) +1

= 338.33+ 1

= 339.33 nos.

By rounding off, the no. of stirrups required = 340 nos. 

Now, let us prepare a BBS (Bar Bending Schedule) table for the plinth beam.

sl.    bar                    dia.     no.     length    total      weight       total

no.                        ( mm)                 (m.)     length     kg/m      weight

1.  main bar              12         4    59.264    237.056         0.89     210.98

2. stirrups                 8        340    0.844    286.96    0.395     113.35

Total weight of bars  =  324.33 kgs.

Add 2% wastage          = 6.49  kgs.

Grand total of rebars  =  330.82 kgs. 

6. Quantity of Materials in RCC Column:

Let us make a rcc column of size 9″ × 9″  as shown in the drawing.

Given data :

Column height above GL = 6 ft.+ 5″(0.416 ft.) = 6.416 ft.,  below GL = 7″ (0.583ft.)

Size of Column      = 9″ × 9″ (228.6mm × 228.6 mm )

Longitudinal bars 12mm (0.03936 ft.) – 4 nos,  cover  – 40mm.

Lateral ties dia d1 – 6mm @ 6″ (150 mm.) c/c

From part 1, number of columns = 18 nos.

6a. The volume of the column concrete for the compound wall

= total nos. × height × length× breadth

= total nos.  × (height below GL + height above GL )  × length  × breadth

= 18 nos.  × ( 6.416 ft. + 0.583 ft. )  × 0.75 ft. × 0.75 ft.

= 18 nos.  × 7 ft.  × 0.75 ft  × 0.75 ft.

= 70.875 cft. i.e. 2.0 cum.

6b.  BBS of a column for the compound wall.

Length of the longitudinal bar

= above GL + GL to footing top + development length ( Ld )

= 6.416 ft. + 0.583 ft. + ( 50d )

( we have taken Ld as 50d, where d = bar diameter.)

= 7 ft. + (50 × 0.03936 ft.)

= 7 ft. + 1.968 ft.

= 8.968 ft.   i.e. 2.733 m.

Length of the lateral ties

= perimeter of lateral ties + total hook length – no. of bends

= 2 sides × ( a – 2 × cover ) + 2 sides × ( b – 2 × cover ) +( 2nos × hook length) – (3 nos. × bend )

( Here, we have taken  hook length = 10d1 for 135°∠    & bend = 2d1 for 90°∟)

={ [ 2 × (228.6mm – 2 × 40mm.) ] + [ 2 × ( 228.6 mm – 2 × 40 mm.) ] } + { 2 × 10 × 6mm } – {3 × 2 × 6mm }

={ [ 2 × 148.6 mm ] + [2 × 148.6 mm ]} + 120 mm – 36 mm.

= {297.2 mm + 297.2 mm} + 84 mm

= 678.4 mm i.e. 0.678 m.

Total number of lateral ties ( stirrups )

={ [ length of the longitudinal bar – Ld ] ÷ stirrup spacing } + 1

Note:  Ld is deducted from the length, as no stirrups are provided over that length.

= {[ 2733 mm – (50 × 12 mm )] ÷ 150 mm.} + 1

= {[ 2733mm – 600mm ] ÷ 150 mm.} + 1

= {2133 mm ÷ 150 mm.} + 1

= 14.22 + 1

= 15.22 nos.

Rounding off, the number of stirrups required = 15 nos.

Now, let us prepare BBS (Bar Bending Schedule) for a column.

sl.    bar                    dia.     no.     length    total      weight       total

no.                        ( mm)                 (m.)     length     kg/m      weight

1.  longitudinal      12        4        2.733     10.932     0.89        9.729

2. lateral                   6        15      0.678       10.17       0.22       2.237

Total weight of bars  =  11.966 kgs.

Add 5% wastage          = 0.5983 kgs.

Grand total of rebars  =  12.564 kgs. 

The total weight of  bars for compound wall columns

= 18 nos × 12.564 kgs = 226.152 kgs.

7. Quantity of Materials for Estimating Block Masonry of Compound Wall:

Let us build this compound wall of 6″ (inch) thickness having 6 ft. height as shown in the drawing.

The total length of the compound wall

= site perimeter – gate length

= (50ft. × 2 nos.) + (40 ft. × 2 nos.) – 10 ft.

= 100 ft. + 80 ft. -10 ft.

= 170 ft. 

The total length of the block masonry wall

= compound wall length – (no. of columns × width of a single column.)

= 170 ft. – (18 nos.× 0.75 ft.)

= 170 ft. – 10.5 ft.

= 156.5 ft.

Height of the block masonry wall

= compound wall height – coping thickness

= 6 ft – 0.33 ft.

= 5.67 ft.

7a. The volume of the block masonry

= length × height × thickness

= 156.5 ft. × 5.67 ft. × 0.5 ft.

= 433.68 cft.

Number of concrete blocks required

= 210 nos. × ( 433.68 cu ft. ÷ 100 cu ft.)

= 911 nos.

The number of cement bags required

= 1.038 bags × ( 433.68 cu ft. ÷ 100 cu ft.)

=4.501 bags.

The volume of sand required

= 7.634 cu ft. × ( 433.68 cu ft. ÷ 100 cu ft.)

= 33.12 cu ft.

Note: The above-given quantities are taken from the article “Calculating the quantity of materials in a 100 cubic ft. block wall.”

8. Quantity of Materials for Coping and Backfilling of Compound Wall

Let us make coping over block masonry work having 4″ (0.33 ft.) thickness in M15 grade.

8a. The volume of coping for the compound wall

= coping length × width × thickness

= block masonry length × masonry width × coping thickness

= 156.5 ft. × 0.5 ft. × 0.33 ft.

= 25.82 cu ft. i.e. 0.731 cu m.

Let us make this coping in M15 grade concrete.

The number of cement bags required for the coping work

=17.942 bags × (25.82 ÷ 100 cu ft. )

= 4.632 bags.

The total volume of sand required for coping

= 44 cu ft × (25.82 ÷ 100 cu ft. )

= 11.361 cu ft.

The total volume of coarse aggregates required

= 88 cu ft. × (25.82 ÷ 100 cu ft. )

= 22.722 cu ft.

Note: The above quantities for the calculation purpose is taken from “ Calculating the quantity of materials in 100 cu ft. & 1 cum. of M15 (1:2:4 ) grade concrete“.

8b. volume of backfilling for the compound wall

Volume of Backfilling for plinth beam

picture

= Volume of excavation for plinth beam – beam PCC volume – plinth beam volume up to GL.

= [(186.90 cu ft.) – (52.33 cu ft.) – (124.875 cu ft. × 0.583 ft ÷ 1 ft.)

( By volume ratio with plinth beam 👆)

= 186.90 cu ft. – 52.33 cu ft – 72.802 cu ft.

= 61.768 cu ft.

Backfilling for footing:

=[ volume of excavation for footing – {footing vol. – soling vol. – PCC vol. – column vol. up to GL.}]

= [180 cu ft.- {33.74 cu ft. + 54 cu ft. + 23.76 cu ft.+ ( 18 nos × 0.583 × 0.75 × 0.75) } ]

= [180 cu ft – 117.40 cu ft.]

= 62.60 cu ft.

The total volume of backfilling 

= backfilling for plinth beam + backfilling for footing

= 61.768 cu ft. + 62.60 cu ft.

= 124.368 cu ft. i.e. 3.52 cum.

Overall Quantities for Construction Cost of Compound Wall:

First, we will sum up the total quantity of materials from all parts of this compound wall.

The volume of RCC for compound wall

= [for footings+ for plinth beam + for columns]

= [0.95 cum + 3.53 cum. + 2.0 cum.]

= 6.48 cum .i.e. 228.8 cu ft.

Let us make this RCC in M20-grade concrete.

The no. of cement bags required for RCC work

= [8.06 bags × ( 6.48 cum ÷ 1 cum )]

= 52.23 bags

The volume of sand required for RCC work

= [ 0.42 cum × ( 6.48 cum ÷ 1 cum )]

= 2.722 cum.  i.e. 96.1 cu ft.

The volume of coarse aggregates required for RCC work

= [0.84 × ( 6.48 cum ÷ 1 cum )]

= 5.44 cum. i.e. 192.2 cu ft.

Note: The values i.e. directly added above is taken from “Calculating the quantity of materials in different grades of concrete“.

Now, we will sum up the total quantities of cement, sand, & aggregates required for the compound wall construction.

Note: The values i.e. mentioned below are taken from all above 8 parts of the series.

The total number of cement bags for compound wall.

= [for PCC + for masonry + for  RCC + for coping]

= [17.16 +  4.501 + 52.23 + 4.632]

     = 78.523 bags 

The total volume of sand required in the compound works

= [for PCC + for masonry + for  RCC + for coping ]

= [42.09 + 33.12 + 96.1 + 11.361]

 =  182.671 cu ft.

The total volume of coarse aggregates required in the compound work.

= [for PCC + for RCC + for coping]

= [84.19 + 192.2 + 22.722]

     =  299.11 cu ft.

The total weight of rebars required for the compound work.

= for footing + for plinth beam + for columns

=   [56.55 kgs + 330.82 kgs. + 226.152 kgs.]

= 613.522 kgs.

OTHER POSTS:

1. Thumb Rules for Staircase Design Calculation | Concrete Calculation of Staircase

2. How to Calculate the Shuttering Quantity for Staircase

3. Thumb Rules for Staircase Design Calculation | Concrete Calculation of Staircase

4. Bar Bending Schedule of Staircase | Staircase Reinforcement Detail

Conclusion:

In conclusion, preparing a compound wall estimate with a bar bending schedule is an essential part of the construction process. It ensures that the right amount of material and resources are utilized, making the construction process more efficient and cost-effective. A bar bending schedule also helps in ensuring the strength and stability of the wall, making it a crucial aspect of any construction project.

The post Compound Wall Estimate Guide with Bar Bending Schedule appeared first on The Civil Engineering.

The Flight of Stairs refers to a series of steps or a staircase that leads from one level (floor) of a building to another.

Flight of Stairs Definition:

A Stairway or set of steps connecting one floor or landing to the next.

Number of Steps Require In A Flight Of Stairs?

How to find Flight of Stairs per Floor?

1. Measure the height of each floor: This can be done by measuring the distance from the floor of one level to the ceiling of the level above.
2. Divide the height of each floor by the height of one stair: This will give you the number of stairs per flight.
3. Count the number of flights of stairs: This can be done by counting the number of times the stairs change direction or by counting the number of landings between flights.
4. Multiply the number of stairs per flight by the number of flights: This will give you the total number of stairs per floor.
5. Repeat steps 1-4 for each floor of the building: This will give you the number of flights of stairs per floor for the entire building.

Design Criteria for Staircase:

Width of Stair:

• The width of the stair should be sufficient for two persons to pass on it simultaneously and for furniture and other things to be carried up and down the stair.
• The minimum width of the stair should not be less than 80cm. in any case.
• For residential buildings width should be at least 90 cm.
• For public building should be between 1.5 m to 1.8 m.
• If the width is more than 1.8m, central handrail should be provided

Design of Layout:

Headroom:

Flight:

Single Step:

Winders:

Handrails:

Benefits Of A Flights Of Stairs:

Total Steps In A Flight Of Stairs?

Total Steps For 8 Feet Ceilings:

How Long Is A Flight Of Stairs?

How Tall Is A Flight Of Stairs?

OTHER POSTS:

1. Thumb Rules for Staircase Design Calculation | Concrete Calculation of Staircase

2. How to Calculate the Shuttering Quantity for Staircase

3. Thumb Rules for Staircase Design Calculation | Concrete Calculation of Staircase

4. Bar Bending Schedule of Staircase | Staircase Reinforcement Detail

5. Compound Wall Estimate Guide with Bar Bending Schedule

FAQs:

The post Flight of Stairs | How Many Flight of Stairs per Floor | Design Criteria appeared first on The Civil Engineering.

How to Calculate Load on Footing for Structural Support

In this blog post, we will explain how to calculate load on building footing and the different types of loads acting on it. We will also cover the formula and calculation used in the process, as well as the factors that can affect the load on a building footing or foundation load calculation. The post will also provide insight on why it’s important to consult a professional structural engineer for the proper calculation of loads on building footing and the foundation design.

Footing is one of the major structural elements that transfer the load safely to the soil. The slab load will transfer to the beam load, which will transfer to the column. The column will transfer the load to the footing, which has to safely transfer the load to the soil.

What is Footing?

It is the lowermost part of the foundation that has been constructed below Ground level in solid surface.

Purpose of footing?

Transfer the live load and dead loads of the structure over a large enough area so that neither the soil nor the building moves. Resist settlement and lateral load.

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Load Calculation Procedure for Footing:

Before we begin the calculation, let’s take a look at the loads that will be applied to the footing.

Calculate Load acting on Footing | Calculation Example

1. Load from Slab
2. Load from Beam
3. Plinth Beam Load + Wall Load
4. Column Load
5. Self Weight of Footing
6. Backfilling Load

Given Structural Dimensions:

• Column Size = 9″ x 15″
• Beam Size = 9″ x 15″
• Slab Thickness = 5″
• Size of Footing = 4′ x 4′ x 12

1- Calculate Load from Slab:

Slab Thickness = 5″ = 0.125m

Footing Calculation Formula: Self Weight of Slab = Volume of Slab x Unit Weight of Concrete

Self Weight of Slab = (1 x 1 x 0.125) x 25

Self Weight of Slab = 3.125 KN/m²

Floor Finish Load = 1.5 KN/m²

Live Load = 2.0 KN/m²

Total Load on Slab = Self weight of Slab + Floor Finish Load + Live Load

Total Load on Slab = 3.125 + 1.5 + 2.0 = 6.625 KN/m²

Influence Area (C1) = L/2 x W/2

Influence Area (C1) = 3.88/2 x 3.12/2 = 1.94 x 1.56

Influence Area (C1) = 3.03 m²

Slab Load on Column = Total Load on Slab x Influence Area (C1)

Slab Load on Column = 6.625 x 3.03

Slab Load on Column = 20.07 KN

2- Calculate Load from Beam:

Beam Size = 9″ x 15″ = 0.225 m x 0.375 m

Footing Calculation Formula: Self Weight of Beam = W = Unit Volume of Beam x Unit Weight of Concrete

Self Weight of Beam = W = (1 x 0.225 x 0.375) x 25

Self Weight of Beam = W = 2.11 KN/m

B1 Beam Load on Column C1/C2 = WL/2

B1 Beam Load on Column C1/C2 = (2.11 x 3.88)/2

B1 Beam Load on Column C1/C2 = 4.09 KN

B3 Beam Load on Column C1/C3 = WL/2

B3 Beam Load on Column C1/C3 = (2.11 x 3.12)/2

B3 Beam Load on Column C1/C3 = 3.29 KN

Total Load on C1 from Beams = 4.09 + 3.29

Total Beam Load on C1 from Beams = 7.38 KN

3- Calculate Load from Plinth Beam & Wall:

Plinth Beam Size = 9″ x 15″ = 0.225 m x 0.375 m

As we know that the size of beam is same as Plinth Beam so the Total Load on C1 from Plinth Beam are also same to the Total Load on C1 from Beams so,

Total Load on C1 from Plinth Beams = 7.38 KN

Height of Wall = Overall Height – Beam Depth

Height of Wall = 3 – 0.375 = 2.625 m

Footing Calculation Formula: Self Weight of Wall on Plinth Beam = W = Volume of Wall x Density of Bricks

Self Weight of Wall on Plinth Beam = W = (1 x 0.225 x 2.625) x 20

Self Weight of Wall on Plinth Beam = W = 11.81 KN/m

B1 Wall Load on Column C1/C2 = WL/2

B1 Wall Load on Column C1/C2 = (11.81 x 3.88)/2

B1 Wall Load on Column C1/C2 = 22.91 KN

B3 Wall Load on Column C1/C3 = WL/2

B3 Wall Load on Column C1/C3 = (11.81 x 3.12)/2

B3 Wall Load on Column C1/C3 = 18.42 KN

Total Load on C1 from Walls = 22.91 + 18.42 = 41.33 KN

4- Calculate Load from Column:

Column Size = 9″ x 15″ = 0.225 m x 0.375 m

Height of Column = (Height Above Ground + Hight Below Ground) = 3 + 1.5 = 4.5 m

Footing Calculation Formula: Self Weight of Column = W = Volume of Column x Density of Concrete

Self Weight of Column = W = (0.225 x 0.375 x 4.5) x 25

Self Weight of Column = W = 9.49 KN

5- Calculate Self Weight of Footing:

Size of Footing = 4′ x 4′ x 12″ = 1.22 m x 1.22 m x 0.30 m

Footing Calculation Formula: Self Weight of Footing = W = Volume of Footing x Density of Concrete

Self Weight of Footing = W = (1.22 x 1.22 x 0.30) x 25

Self Weight of Footing = W = 11.16 KN

6- Calculate Backfilling Load:

Volume of Footing = 1.22 x 1.22 x 0.3 = 0.446 m³

As we know that the size of footing excavation = 4′-4″ x 4′-4″ x 1.5= 1.32 m x 1.32 m x 1.5 m

Volume of Footing Excavation = 1.32 x 1.32 x 1.5 = 2.61 m³

Volume of Filling = Volume of Footing Excavation – Volume of Footing

Volume of Filling = 2.61 – 0.446 = 2.164 m³

As we know that Unit Weight of Earth = 18 KN/m³

Backfilling Load = Volume of Filling x Unit Weight of Earth

Backfilling Load = 2.164 x 18 = 38.95 KN

Total Load on Footing:

1. Load from Slab = 20.07
2. Load from Beam = 7.38
3. Load from Plinth Beam & Wall = 7.38 + 41.33 = 48.71 KN
4. Load from Column = 9.49 KN
5. Self Weight of Footing = 11.16 KN
6. Backfilling Load = 38.95 KN
   so, Total Load acting on Footing = 135.76 KN

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Factors that Affect Load on Building Footing:

Conclusion:

In conclusion, determining the load on a building’s footings is an important phase in the building process. The building’s footings can withstand the weight of the structure if the calculations are done correctly, averting expensive and dangerous structural problems. The load on a building’s footings can be determined in a number of ways, including manually, via advanced structural design software, and by consulting an expert. It’s crucial to pick the best approach that works for your particular building project.

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OTHER POSTS:

1. Thumb Rules for Staircase Design Calculation | Concrete Calculation of Staircase

2. Compound Wall Estimate Guide with Bar Bending Schedule

3. Thumb Rules for Staircase Design Calculation | Concrete Calculation of Staircase

4. How Many Flight of Stairs per Floor

5. Bar Bending Schedule for One Way Slab

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FAQs:

The post How to Calculate Load on Footing for Structural Support appeared first on The Civil Engineering.

Calculate Bar Bending Schedule for One Way Slab | Steel Quantity for One Way Slab

Bar bending schedules are vital in determining the quantities of reinforcement used in steel or concrete slabs. To find out bar bending schedules of slab, you should learn first Bar Bending Schedule Formula or Basics of Bar Bending Schedule and how to use concrete covers. We will also discuss about the rebar for concrete slab calculator, calculation formula, calculate rebar spacing, slab of steel quantity, reinforcement bbs bar bending schedule for slab and many more about the steel quantity for one way slab

Bar Bending Schedule for Slab:

In construction, there are 16 different slab varieties. Well, the thickness of a slab typically ranges from 4 to 8 inches. Generally, our slabs are 6′′ (0.15m) thick. We use slabs that are 8′′ and over in thickness for occasional heavy loads.

Before calculating the BBS of One Way Slab, we should know about the function and detail of one way slab;

One Way Slab:

One way slabs are those in which the ratio of longer spans (L) to shorter spans (B) is equal to or greater than 2. In a one-way slab, the load is carried in one direction, where main bars are designed, and in the opposite direction, where thin bars—known as distribution bars—are used instead of main bars to distribute the load.

One way slab = Longer span / shorter span > 2

Reinforcement Required for Steel Quantity of One Way Slab & Two Way Slab:

Generally, slabs are classified into two types One-way Slab and Two-way slab, In one-way slab, Main bars run in the shorter direction (called Cranked bars) and distribution bars run in the longer direction (called Straight bars). In two-way slabs, Main bars are available in both directions.

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Bars used in One Way Slab:

Distribution bars:

These bars are straight bars

Main bars:

These bars have a crank. The main bars have a length of 0.42D and are cranked at a 45-degree angle.

Where, D = Depth of Slab- Top cover – Bottom cover

Extra Bars:

To maintain the slab’s structural stability, an additional bar is provided at the bottom of the Cranked bars. 

L/4 is the length of the Extra bar ….. (rebar calculation formula)

Steps to calculate the Reinforcement required for Slab:

1. Subtract the slab clear cover from the distribution and main bar length calculations.
2. Determine the value of “D” (Depth of slab- Top cover- Bottom cover)
3. Calculate the number of bars by using rebar calculation formula
4. Calculate the overall steel weight needed for slab reinforcement.

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Bar Bending Schedule for One Way Slab:

How to Calculate Rebar for Slab

One way slab Reinforcement Detail:

Given Data:

1. Cranked bars or Main bar of diameter 16 mm and C/C spacing 150 mm.
2. Distribution bars of diameter 12 mm and C/C spacing 150 mm.
3. Top and bottom slab clear cover is 25 mm.
4. Side clear cover of RCC slab is 25 mm
5. Thickness of RCC slab is 150 mm.
6. Length of RCC slab is 6000 mm (longest side along beam)
7. Width of slab (Clear Span) without beam is 3000 mm. (shortest side which is perpendicular to beam)
8. Length of top extra bars = L/4 = 3000/4 = 750 mm
9. No. of top extra bars = No. of Main bars
10. Diameter of top extra bars

Now,

For Main bars:

Step 1:- Calculate numbers of main rods.

No. of Main Bars = (Length of Slab)/ Spacing + 1

No. of Main Bars = (6000)/150 + 1

No. of Main Bars = 40 + 1

No. of Main Bars = 41 Nos. 

Step 2:- Calculate cutting length of one main rods (rebar of slab).

Cutting length of one crank bar = Clear span of slab + ( 2 x Development Length) + (1 x inclined length) – (2 x 45 Bend) 

Cutting length of crank bars = 3000 + ( 2 x 40d) + (1 x 0.42D) – (2 x 1d)

(Development length = 40d, inclined length = 0.42D, 45 Bend= 1d)

Where, 

D = Thickness of slab – 2 x Side clear cover – diameter of bars

D = 150 – 2 x 25 – 16 = 84 mm

D = 84 mm

Cutting length of one crank bars = 3000 + ( 2 x 40 x 16) + (1 x 0.42 x 84) – (2 x 16)

Cutting length of one crank bars = 3000 + 1280 + 35.28 + 32

Cutting length of one crank bars = 4347.28 mm

Step 3:- Calculate Total length of main rods.

Therefore Total length of crank bars = Length of one crank bar  x  No. of crank bars …. (steel calculation formula)

Total length of crank bars = 4347.28 x 41 = 178238.48 mm

Total length of crank bars = 178.238 meter. 

Step 4:- Calculate total weight of main rods (rebar for slab).

W1 = (d2 / 162.25) x Length ….. (steel calculation formula)

W1 = (162 / 162.25) x 178.238

W1 = 281.23 Kg

For Distribution bars:

To find the Distribution Bars Cutting Length we will follow the following steps:

Step 1: – Calculate numbers of distribution rods.

To find the Bar Bending Schedule for Slab we use the following formula,

No. of Main bars = (Width of Slab/Spacing) + 1 …. (Rebar Calculation Formula)

No. of Main bars = (3000)/150 + 1 

No. of Main bars = 20 + 1 = 21 Nos.

Step 2:– Calculate cutting length of one distribution bar.

Cutting length of one distribution bar = Length of Slab + 2 x development length

Cutting length of one distribution bar = 6000 + 2 x 40d

Cutting length of one distribution bar = 6000 + (2 x 40 x 12)

Cutting length of one distribution bar = 6000 + 960

Cutting length of one distribution bar = 6960 meter

Step 3:- Calculate Total length of distribution rods.

Therefore Total length of crank bars = Length of one crank bar  x  No. of crank bars

Total length of crank bars = 6960 x 21 = 146160 mm = 146.160 meter.

Step 4:- Calculate total weight of distribution rods.

W2 = (d2 / 162.25) x Length

W2 = (122 / 162.25) x 146.160

W2 = 129.72 kg

For Top Extra bars:

Length of top extra bar = L/4 = 3000/4 = 750 mm

No. of top extra bars = No. of Main bars = 41

Total length of Top extra bars = 750 x 41 = 30750 mm

Total length of Top extra bars = 30.750 meter

Therefore total weight of top extra bars = W3

W3 = (162 / 162.25) x 30.750

W3 = 48.52 Kg

Total Weight of Reinforcement:

Hence,

Total Weight of Steel Rod = Total Weight of crank bars + Total Weight of Distribution bars + Total weight of extra top bars

Total Weight of Steel Rod = W = W1 + W2 + W3

Total Weight of Steel Rod = W = 281.23 kg + 129.72 kg + 48.52 kg

Total Weight of Steel Rod = W = 459.47 kg

Hence, the final calculate weight of steel quantity is 459.47 Kg

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Rebar Calculator for Slab:

Download Excel File

I sincerely hope you find this article on “Bar Bending Schedule for One Way Slab“ to be useful and how to calculate steel quantity for One Way Slab.

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Free Download Excel File

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OTHER POSTS:

1. Basics of Bar Bending Schedule Formulas | BBS Formulas with Example

2. Bar Bending Schedule Basic Formulas | BBS Formula | What is BBS

3. Bar Bending Schedule (BBS) | BBS Step by Step Preparation | Excel Sheet

4. Bar Bending Schedule of Lintel Beam | Typical Beam | Detailed Beam

5. Bar Bending Schedule of Neck Column | BBS Steel Estimation

6. Bar Bending Schedule for RCC Box Culvert in Excel | Download Sheet

7. Bar Bending Schedule for Tie Beams/Strap Beams | BBS of Tie Beam

8. Bar Bending Schedule for footings | Steel Estimation for footings

9. Bar Bending Schedule of Staircase | Staircase Reinforcement Detail

10. Bar Bending Schedule of Staircase With Single Reinforcement Detail

11. How to Make Bar Bending Schedule for Pile Foundation | BBS for Pile

12. How to Calculate Bar Bending Schedule of Slab in Excel | BBS of Slab

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FAQs:

The post Calculate Bar Bending Schedule for One Way Slab appeared first on The Civil Engineering.

The volume calculation is one of the most important steps in constructing a staircase. Without knowing the right stair formula you may not be able to calculate the right amount of concrete needed for your staircase. Also discuss about the stairs quantity takeoff in excel calculator, concrete for steps, dog legged staircase, cost estimation of staircase with landing and much more.

Before, reading about “How to Calculate Quantity of Concrete Volume for Staircase” you should read first about the Introduction of Dog Legged Staircase.

What is Staircase?

A staircases is a part of a building that helps us move from one floor to another. It’s an important part of many buildings. The sizes of staircases vary, depending on the kind of building they’re meant to fit into.

Definition of Staircase: A flight or series of flights of steps and a supporting structure connecting separate levels.

Dog Legged Staircase:

A dog legged Staircase is a stair configuration that has a quarter-landing before turning at a right angle and continuing upwards. The flights do not have to be equal, and frequently are not.

Various Parts of Staircase or Concrete Stairs:

Waist slab:

A stair’s slab that slopes upward from the floor slab to the landing slab is referred to as the waist slab.

Flight:

The series of steps from floor to the landing.

Landing:

The transitional level between flights.

Step:

The step is made up of the tread and the riser.

Tread:

The flat area you step on is known as the tread.

Riser:

The vertical (up and down) portion of a stairway between each tread is known as a riser.

Staircase Concrete Calculation:

We need to calculate concrete volume for staircases for each component separately, then add them all up to find the total volume of concrete for dog legged staircases.

Staircase Concrete Calculation Formulas:

• No. of Riser = Height of the Flight / Riser
• No. of Treads = No. of Risers – 1
• Concrete Calculation Formula for Step = 1/2 x Riser x Tread  x Length of Step
• Concrete Calculation Formula for Flight = Volume of one Step X No, of Treads
• Length of Waist Slab Formula = √ (Horizontal Length)² + (Height)² {When Base and height of triangle is given}
• Concrete Calculation Formula for Waist Slab = Length x Width x Thickness
• Concrete Calculation Formula for Landing = Length x Width x Thickness

Staircase Concrete Calculator:

Quantity of Concrete Volume for Staircase:

From the drawing:

Tread = 10″ = 0.833 ft

Riser = 6″ = 0.5 ft

Height of the Flight = 12 ft

Length of the Landing = 8′ – 6″ = 8.5 ft

Width of the Landing = 3 ft

Thickness of the Landing = 6″ = 0.5 ft

Length of Flight or Waist Slab = ?

Width or Length of Steps = 4 ft

Step 1: Find the Number of Risers and Treads?

No. of Riser = Height of the Flight / Riser = 12 / 0.5 = 12 Risers

No. of Treads = No. of Risers – 1 = 12 – 1 = 11 Treads

Step 2: Find the Concrete Volume for One Flight (All Steps)?

The Volume of Concrete for one step = Area of one Step x Length of Step

As you know that the shape of stair step is right angled triangle so we know the formula for the area of right angled triangle is:

Area of One Step = 1/2 x riser x tread

The Volume of Concrete for one step = 1/2 x riser x tread x Length of Step

Volume of Concrete for one step = 1/2 x 0.5 x 0.833 x 4

The Volume of Concrete for one step = 0.833 cft

Therefore, the total volume of concrete required for steps on first flight = Volume x No. of Steps

= 0.833 x 11 = 9.163 cft

The above calculation is only for one flight. We know that the second flight are having the same measurements:

so, Total Concrete = First Flight Concrete Volume x 2 = 9.163 x 2 = 18.326 cft

Step 3: Find the Concrete Volume of Landing Space?

As per the given Plan,

Length of the Landing = 8′ – 6″ = 8.5 ft

Width of the Landing = 3 ft

Thickness of the Landing = 6″ = 0.5 ft

Volume of Landing = Length x Width x Thickness = 8.5 x 3 x 0.5 = 12.75 cft

Step 4: Find the Concrete Volume of Waist Slab?

As we know that, It is the right angled triangle in order to find the inclined length we use the Pythagoras theorem;

Inclined Length = √ (Horizontal Length)² + (Height)²

Horizontal Length = Tread Size X No. of Treads = 0.833 x 11 = 9.163 ft

As we know that Height = 12 ft, so,

Inclined Length = √ (Horizontal Length)² + (Height)²

• Inclined Length = √ (9.163)² + (12)²

– Inclined Length = 15.09 ft

Concrete Volume of Waist Slab = Inclined Length x width of Slab x Thickness of Slab

Concrete Volume of Waist Slab = Inclined Length x width of Slab = 15.09 x 4 x 0.5 = 30.18 cft

As we know that there are two flights with two waist slabs so,

Total Volume of Waist Slab = Volume of Waist Slab x 2 = 30.18 x 2 = 60.36 cft

Step 5: Total Quantity of Concrete Volume for Staircase ?

Staircases Concrete Volume = Steps Volume + Landing Space Volume + Waist Slabs Volume

Staircases Concrete Volume = 18.326 + 12.75 + 60.36 = 91.436 cft

Staircase Concrete Volume = 91.436 cft

Material and Cost Analysis for Staircase Concrete:

Now we will find the material analysis of dog legged staircases concrete;

Calculation for Quantity of Cement, Sand and Aggregate in Concrete?

Wet Volume of Staircases Concrete = 91.436 cft

Dry Volume of Staircase Concrete = 91.436 x 1.54 = 140.81 cft

Ratio of Concrete = 1 : 1.5 : 3 (c : s : a)

Sum of Ratios = 1 +1.5 + 3 = 5.5

so, Cement Content in Concrete = Dry Volume of Concrete / Sum of Ratios x Ratio of Cement

Cement Content in Concrete = 140.81 / 5.5 x 1 = 25.60 cft

As we know that, 1 Cement Bag (50 kg) = 1.25 cft

No. of Cement Bags = 25.60 / 1.25 = 20.48 = 21 Bags (Say)

Sand Content = Dry Volume of Concrete / Sum of Ratios x Ratio of Sand

Sand Content = 140.81 / 5.5 x 1.5 = 38.40 cft Sand

Stone Chips or Aggregates = Dry Volume of Concrete / Sum of Ratios x Ratio of Aggregates

Stone Chips or Aggregates = 140.81 / 5.5 x 3 = 76.80 cft Aggregate

Calculation for Water Content in Concrete?

Now lets calculate the water content of staircase concrete. Suppose, water-cement ratio for staircase concrete is specified 0.45.

That means, water/cement = 0.45, or W/C = 0.45

for 1 bag cement, water is, = 0.45 x 1.25 (as we know, 1 bag cement equal to 1.25 cft),

Water = 0.5625 cft.

As we know 1 cubic feet water is equal to 28.31685 litre,

So we can write, water = 0.5625 x 28.31685 = 15.92 litre, say, 16 litre.

So One bag of Cement needs 16 liter of water for 0.45 W/C ratio.

Required Water Content for Staircase Concrete = Req Quantity of Cement Bags x 16 litres

Total Required Water Content for Staircase Concrete = 21 x 16 = 336 litres

Material Statement for Staircase Concrete?

Cement = 21 Bags

Sand = 38.40 cft Sand

Aggregates = 76.80 cft Aggregate

Water = 336 litres

Cost or Rate Analysis for Staircase Concrete?

Cement = 21 Bags x 1070 RS/Bag = 22,470 RS

Sand = 38.40 cft x 65 RS/cft = 2,496 RS

Aggregates = 76.80 cft x 50 RS/cft = 3,840 RS

Water = 336 litres x 2.50 RS/litre = 840 RS

Total Cost = 22,470 + 2,496 + 3,840 + 840 = 29,646 RS

OTHER POSTS:

1. Thumb Rules for Staircase Design Calculation | Concrete Calculation of Staircase

2. How to Calculate the Shuttering Quantity for Staircase

3. Thumb Rules for Staircase Design Calculation | Concrete Calculation of Staircase

4. Bar Bending Schedule of Staircase | Staircase Reinforcement Detail

5. Bar Bending Schedule of Staircase With Single Reinforcement Detail

6. Bar Bending Schedule for One Way Slab

The post How to Calculate Quantity of Concrete Volume for Staircase appeared first on The Civil Engineering.

Dog Legged Staircase | Components and Design of Dog Legged Stair:

In this article we will discuss Dog Legged Staircase and their facts, advantages, disadvantages, dog Leg Staircase plan, stair design calculator with an example calculation for rise and tread, calculation formula for stairs, risers and treads and how to calculate design of staircase calculations.

What is a staircase?

A stair is a structure with a series of steps meant to provide a simple and easy means of ascending and descending between levels or floors. The room or enclosure at the top of the stairs is known as a landing, and the space at the bottom of the stairs is called a step.

Dog-legged stair or Dog Legged Staircase?

The dog-legged staircase is a type of staircase that consists of two flights of stairs running in opposite directions. 

The stairs are designed such that they turn and continue to move upward two steps before making a 180-degree turn, thus maintaining their upward trajectory.

This type of staircase, which resembles the shape of a dog’s leg in the sectional elevation, is also known as dog-legged. 

The dog-legged staircase is efficient at utilizing the space available, making it an excellent choice for residential, public and commercial buildings. It also allows for better circulation and compact space utilization.

Fact Behind It’s Name of Dog Legged Staircase:

The dog-legged staircase looks like a dog in elevation. It has a sloped angle similar to the slope between the dog’s legs. 

Is the Length of Flight Equal?

No, the length of both flights isn’t needed to be equal. Most of the time, it is kept unequal. 

This type of staircase is used in residential, commercial, institutional, and public buildings. 

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Suitability of Dog Legged Staircases

If you don’t have much space, the stairs can be the best. Typically this staircase will be sized two times larger than its tread width.

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Components of Dog Legged Staircase:

A Dog-Legged Staircase Plan consist of components such as:

Stair Tread:

The part of the staircase on which your foot lands is called a tread.

Stair Rise:

The space between two stair treads is called a riser.

Newel post:

The vertical post at the start and end of the flight is called a newel post. It supports the stairs and creates a resting place for your feet as you climb up or down.

Baluster:

A baluster is a vertical support installed throughout the length of a flight on which a handrail is supported to prevent falls.

Landing:

Landing is a platform provided to break the continuity of flight for providing rest to the user.

Handrail:

A handrail is the part of the staircase that people hold onto for support when going up and down the stairs. The handrail must provide stability and a continuous guide along the stair.

Stair Stringer:

A stair stringer is the housing that holds the treads and risers in place on either side of a flight of stairs.

Pitch:

The angle at which a line of nosing makes with a horizontal surface is called pitch.

Line of Nosing:

The line of going is a hypothetical imaginary line parallel to the slope of the staircase that joins the nosing. 

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Requirements of a Good Dog Legged Staircase:

The criteria or requirements to consider while designing a dog-legged staircase are discussed below.

Location:

• In order for the staircase to be freely accessible from all points on the floor, it should be placed in the middle of the room.
• The stairs should remain well-lit and ventilated.

Flight Length:

• On a flight, there must be a minimum of 3 risers.
• In order to comfortably navigate the staircase, a flight should have no more than 16 risers. The continuity must be broken with a landing.

Pitch or Slope:

• A staircase should have a slope of between 25 and 40 degrees.
• The slope shouldn’t be kept below 15° C, though.
• The slope would be too steep to cross if it was over 55 °C.

Step Ratio:

• Both flights of the staircase should have the same rise to going ratio.
• The rhythm will be broken and the person ascending the staircase will feel uneasy if there is a variation in the ratio.

Landing:

• The landing’s width shouldn’t be any less than the flight’s tread.

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Advantages of Dog-Legged Staircase:

1. The staircase has a very straightforward design.
2. Staircase drafting is similarly simple and quick.
3. More carpeting is available for use since space is used more effectively, reducing waste.
4. With this style of staircase, neither the top floor nor the bottom floor are visible from the top, maintaining the privacy of the floors.
5. This kind of stairway can readily include architectural effects.
6. The landing offers a place to rest, making commuting simpler.

Disadvantages of Dog-Legged Staircase:

1. The dog-legged staircase is fairly challenging to build.
2. Because installing handrails is extremely complex, it is important to plan carefully before providing them.
3. A staircase’s handrails are a crucial component that help with climb and descent.
4. It can be challenging to carry large goods up the stairway.

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Design Steps of Dog Legged Staircase:

The following is a list of the numerous steps that went into creating the dog-legged staircase:

Height of Riser and Tread:

First, it is anticipated that each tread will need the height of the rise and the length needed.

Depending on the type of building, the needed length for each tread must be between 250mm and 350mm, while the required height of the rising must be between 150mm and 200mm.

Width of Stair:

Then, the width of the stairs is determined

Width of stairs = Total width of staircase/2

Height of Each Flight:

The height of each flight is then determined.

Height of each flight = Total height/2

No. of Risers in Each Flight:

The Nos of risers in each flight is calculated.

No. of risers in each flight = Height of each flight / Height of riser in each flight

No. of Treads in Each Flight:

The Nos of treads is then calculated.

No. of tread in each flight = No. of risers in each flight – 1

Length of Tread:

Then, the total length required for treads is determined as,

Total length required for treads = Length required for each tread x no. of treads in each flight

Remaining Length:

The length that is left over is then determined by deducting the length taken up by the treads from the total length that is available.

Remaining length = Total length – Total length occupied by the treads

Passage Space:

The length of the landing is then assumed and subtracted from the above calculated remaining length to determine the amount of space that needs to be left for the passage.

Passage space = Remaining length –  Length of landing

In the case that the passage space is not required, the length of the tread can be increased such that all of it is covered by treads and landings.

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Numerical Example for Design of Dog Legged Staircase Calculation:

Example of Dog Legged Staircase or Stair Design Calculator:

Answer the following question to construct a dog-legged staircase with the specified size for a residential structure.

The vertical distance between the floors in the building is 3.9 metres. The staircase’s stated dimensions are 3.6 x 5 m.

Solution:

Step 1: Assume the riser and tread dimensions. 

Let, the height of riser is 150mm and the length required for each tread be 250mm respectively.

Step 2: Calculation of the width of the stairs.

Let, the number of flights is 2. Now,

Width of stairs = 3.6 / 2 = 1.80 m = 1800 mm

Step 3: Calculation of height of each flight.

Height of each flight = 3.9 / 2 = 1.95 m = 1950 mm

Step 4: Calculation of no. of the riser in each flight

No. of risers in each flight= Height of each flight / Height of riser in each flight

= 1950 / 150 = 13 risers

Step 5: Calculation of no. of tread in each flight

No. of tread in each floor = No. of risers in each flight – 1

= 13 – 1 = 12 treads

Step 6: Calculation of length required for treads

Total length required for treads  = 12 x 250 mm = 3000 mm = 3 m

Step 7: Calculation of Remaining Length

Remaining Length = 5 m – 3 m = 2 m

Step 8: Calculation of Space for Passage | Dog Legged Staircase

Space for Passage = 2 m – 1.5 m

(assume width of landing = 1.5m)

= 2 m – 1.5 m = 0.5 m

Dog Legged Staircase Plan:

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Dog Legged Stair Calculator (Stair Design Calculator):

For Stair Design Calculator please follow the table below:

Type of stair	Dog legged
Assumed height of the riser	160 mm
Assumed depth of tread	230 mm
Number of flight	2
Height of floor	3500
Number of riser	(3500/2) /160 = 10.93 = 11 Riser
Number of treads	R-1 = 11 – 1 = 10
Width of Landing	No. of tread * depth of tread = 11 * 230 = 2530

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FAQ’s

The post Dog Legged Staircase, Components & Design of Dog Legged Stair appeared first on The Civil Engineering.

Curing Concrete | Method of Curing | Purpose of Curing | Minimum Curing Period of Concrete

The article will clearly explain the Find out the secret behind curing concrete and learn all about the different types or methods of curing, cure time for concrete, and the purposes of cured concrete. Read our guide to understand how long time or curing period you should let it cure, and what types of curing are best for your project.

What is Curing?

Curing is a process that occurs during which a chemical or physical reaction takes place, resulting in a harder, tougher or more stable linkage or substance. Some curing processes require maintenance of certain temperatures and/or humidity levels, while others require a certain pressure.

Curing of Concrete:

Curing is the process by which concrete hardens. When you add water to a concrete mixture (cement, sand and aggregate), an exothermic reaction takes place (oxygen combining with carbon dioxide) that helps the concrete harden. This happens very quickly, but it takes a long time for the concrete to actually become dry. So, the concrete is kept moist until the hydration reaction in concrete completes. This process is called “Curing of Concrete.”

or

Curing is the process that keeps concrete moist to protect it from loss of moisture due to atmospheric temperature and hydration reactions.

Purpose of Curing of Concrete:

Hydration describes the relationship between water and cement. This reaction is exothermic (which releases heat). Hydration begins when water is added to the concrete mixture, which causes the concrete to start drying out quickly. In order to prevent concrete from drying out before reaching its maximum strength, concrete is maintained moist via curing.

HOW LONG DOES CONCRETE TAKE TO CURE?

After hardening, concrete doesn’t reach its full strength instantly. It has to go through the curing process first. As a result, you have to wait a little longer before putting any weight on it – so if you’ve just laid a driveway, keep your car away from it:

Curing Time of Concrete:

The concrete mix actually gets stronger as time goes on, but to reach practical strength, most industrial concrete mixes have a 28 day curing period or cure time for concrete

After seven days, the concrete will have gained around three quarters of its compressive strength. However, you should refrain from driving vehicles or heavy machinery over the surface until after 28 days.

For concrete that you’re going to use in your driveway, it should set within 24-48 hours. But if you want to park the family car on it for 28 days, be sure to let it cure for that long before driving over it. You might think your concrete is strong enough after taking a test walk on it, but overloading it before it’s fully cured could undo all the hard work you’ve put into its construction.

Minimum Curing Period of Concrete:

As per IS 456 – 2000 | Concrete should not be cured under 7 days for ordinary Portland Cement and at least 10 days for concrete with mineral admixtures or blended cement. In case of hot weather and arid temperature conditions, the curing should not be less than 10 Days for OPC and 14 days for concrete with blended cement & mineral admixtures.

Concrete Cure Time Based on Cement Types:

The minimum curing period of concrete structures is dependent on the type of cement used.

Table-A: Cure time of Concrete Based on Types of Cement

Types of Cement	Curing Time
Type I, ASTM C 150—When the special attributes listed for any other type are not necessary, use this type.	7 days
Type II, ASTM C 150—When a moderate sulphate resistance is necessary, for general use, but especially.	10 days
Type III, ASTM C 150— When a high level of early strength is wanted, utilise.	3 days
Type IV, ASTM C 150—For used when a low heat of hydration is desired.	14 days
Type V, ASTM C 150—For used when high sulfate resistance is desired.	14 days
Hydraulic Cement, Blended Hydraulic Cements, Expansive Hydraulic Cement	Varies

Minimum Curing Time of Different Concrete Constructions:

Table-B: Minimum Concrete Cure Time for Different Types of Construction

Construction types	Examples	Curing period, days
Pavement and other slabs on grounds	Highway pavement, airfield pavements, canal lining, parking lots, driveway, walkways, and floors	Refer to Table-A
Buildings, bridges, and other structures	Cast-in-place walls, columns, slab, beams, all other portions of buildings except slab-on-grade, small footings, piers, retaining walls, tunnel linings, and conduits.	Refer to Table-A
Unreinforced huge portions not incorporating crushed granulated blast furnace slag or pozzolan	–	14
Massive unreinforced sections that comprise pozzolan or ground-granulated blast furnace slag	–	21
Reinforced mass concrete	–	7
Colored concrete floor and slabs	–	7
Shrinkage-compensating concretes	–	7
Roller-compacted concretes	–	14
Shotcretes	–	7

Concrete Compressive Strength Development V/S Curing Time:

Days	Compressive Strength
1 Day	16%
3 Day	40%
7 Day	65%
14 Day	90%
28 Day	99%

Factors Effecting on Concrete Curing:

The cure time or period of concrete is dependent on the following factors:

1. Specified Strength of Concrete
2. Grades of concrete
3. Temperature – The chemical reaction between cement and water in concrete creates heat, which requires constant adding of water to complete hydration. In summer, fifty percent of the water evaporates from the mixture. So, more water is needed during sunny days. 
4. Size and Shape of the Concrete member
5. Economy
6. Material availability
7. Labor force
8. in situ versus plant concrete production
9. Aesthetics

DIFFERENT TYPES OF CURING METHODS IN CONCRETE CONSTRUCTION:

There are various methods of curing concrete or Types of Curing, which are used on the site depending upon the size and nature of the work. There are three major methods of curing concrete by which concrete can be kept moist and humid or kept at a favorable temperature. Here we have given brief information on some of these methods.

Methods of Concrete Curing:

Following are the most important techniques which are prominently used for concrete curing all over the world.

1. Ponding:

This method of floor slab construction involves the use of concrete that has been allowed to harden for 14 days. The concrete is divided into small ponds, and these ponds are filled with water continuously until the surface is completely covered.

2. Wet Coverings:

This type of method is used for columns, footings and the bottom surface of slabs where ponding cannot occur. Impermeable coverings like gunny bags or hessian are required to cover the concrete; these membranes sprayed with water to keep moisture in.

3. Membrane Curing of Concrete: 

Ponds are not suitable in high-temperature areas. Water evaporates when the air outside is too hot. To prevent this, membranes are used to keep the concrete dry and retain its moisture.

The membrane curing process seals off by forming an impermeable layer on the concrete surface, preventing evaporation.

This procedure is generally performed by spraying or brushing a curing compound onto the concrete.

There are numerous curing agents available to achieve membrane curing; nevertheless, the following four techniques are crucial and frequently employed.

Synthetic resin curing compound:

When applied to a concrete surface, synthetic resin hardens into an impermeable membrane that prevents water from evaporating from the concrete.

The synthetic resin membrane can be simply removed before continuing with the plastering process by sprinkling hot water over the concrete surface.

Therefore, it is appropriate for locations where concrete will receive further treatment.

Acrylic curing compound:

Acrylic-based curing compound is a polymer-based curing compound obtained from the polymers of acrylic acid.

The best part of this compound is that it does not need to be removed for plastering; it helps achieve excellent adhesion to plastering.

Wax Curing compound:

Wax curing compound has similar properties to synthetic resin. However, it is not recommended for use on surfaces to be painted or tiled because it will hamper the adhesion between surface and plastering or tiling.

Chlorinated rubber curing compound:

When chlorinated rubber is used to seal the concrete, it forms a thick membrane that seals the pores of the concrete effectively without leaving any minute holes.

However, chlorinated rubber is very expensive and it tends to deteriorate over time.

4. Steam Curing of the Concrete:

The process of spraying steam on precast concrete has been adopted at a precast concrete plant where the concrete members are mass-produced. Steam has heat moisture in it and is sprayed on the surface of the concrete to keep its moisture content high and also increase its temperature.

This helps speed up the curing process, which eventually results in more durable concrete.

5. Curing of Concrete by infrared radiation:

In areas with a chilly climate, this approach is used. In this process, the concrete is exposed to infrared radiation, raising its starting temperature and enhancing its strength. As boosting the beginning temperature of concrete does not reduce the final strength of concrete, this approach is more successful than steam curing.

This method is used for hollow concrete members, where heaters are installed in concrete members to emit 90 degree.

6. Curing of the Concrete Surface by an Electric Current:

In this method, alternating current is applied to concrete. Two electrodes—one at the top and another at the bottom of the cured concrete surface—function as electrodes, and then an alternating voltage is generated between them. By maintaining a 30V or 60V potential difference between these electrodes, curing by this method can be achieved in three days; however, curing at 28 days requires only three days.

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What is Gable Roof | Types and Parts of Gable Roof | Advantages and Disadvantages of Gable Roof 

Gable Roof:

Roofs are an essential part of every building structure. Without them, the rest of the building would be exposed to rain, hail, frost and other weather conditions. Since they play such an important role in protecting the rest of the building, many different types of roofs have been designed over time. One such type is a gable roof. We will also discuss the types of Gable Roof here;

The gable roof is a type of roof that is very common in cold climates.

It’s also known as the classical or Gabled roof. It is made up of two roof sections sloping in opposite directions, which meet at the highest horizontal edges to form the roof ridge.

What is Gable Roof?

The gable roof is also called a pitched roof. It has two sloping sides which meet to form a ridge at the top center of the structure. Most buildings, including many modern homes, use this type of roof.

A gable roof system can add an interesting twist to a modern design by giving it a distinctive look, mixing and matching various elements like decor, functionality, and elegance.

As a result of this, gable roofs are more common over the world due to their ease of construction.

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Historical Development of Gable Roof:

The gable-style roof has a long history in Greek culture. A gable-style roof was utilized to make a roof for a Greek temple in ancient times. The gable roof increasingly gained popularity in countries such as Europe and America.

Gable roof shapes are still utilized to create buildings in certain European and American countries today.

Buildings with gabled roofs became common between the 14th and 17th centuries. The building of gable roofs also affected Italian architecture during this time.

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Types of Gable Roofs

following are five gable roof types,

1. Box Gable Roof
2. Front Gables
3. Cross Gable Roofs
4. Gable Roof With Shed Roof Addition
5. Dutch Gable Roofs

1. Box Gable Roof

A box gable roof has a triangular extension at each end of the house, with a boxed section of roof at each end. The design is extremely similar to the standard gable roof, but distinguishes itself with its triangular shape.

2. Front Gable Roof

A front gable roof is positioned at the front of the house, with the front door under the gable. This is common in Colonial-style homes, but recent years have seen this type of design become increasingly popular.

3. Cross Gable Roof

A cross gable roof is another type of gable roof which created when two or more gable rooflines intersect at an angle. Cross gable roofs often result in more complex layouts for homes, as the change in shape will affect the structure of the house. For example, some homes with cross gable roofs have separate wings, larger porches, or attached garages.

4. Gable Roof With Shed Roof Addition

Many property owners extend the length of their homes by adding a shed roof to the gable roof ridge. This hybrid design is a popular solution for extending, as it provides the opportunity for more headroom and space without having to completely alter the structure and aesthetics of the roof.

5. Dutch Gable Roof:

A Dutch gable roof is a hybrid of a gable and hip roof. The typical design composes of the gable roof being placed on top of the hip roof, providing more space within the loft. This is a popular design with many property owners.

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Design of Gable Roof:

From the roof ridge point, the gabled roof structure is made up of two opposite side parts. The apex of the gable roof connects the two side slope parts. This is referred to as the ridge point.

The gable roof’s pitch and gutter are designed in accordance with the building’s design. A ridge board runs parallel to the rooftop and outside walls, giving the roof its shape.

Between the tops of two common rafters is the ridge board. This ridge board is nailed to the rafters. The rafter is secured in such a way that the slope continues to be downward. Along the exterior walls, the rafter is attached to the nail.

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Parts of Gable Roof (Components):

The main parts of gable roof are Eaves, Gable, Flashing, Hip, Ridge, Purlins, Fascia, Rafter, Battens, and, Joist.

Eaves:

The lower portion of the roof projects beyond the outer wall. These are the sides of a roof that overhang a structure.

The eave of a typical home, usually in the attic, is an excellent place to install insulation because it connects the outside wall to the roof.

Gable:

Gables are the triangular upper parts of walls at the ends of ridges in roof structures. In recent buildings, gable ends are treated in similar ways as classical pediments. However, unlike classical structures that operate through trabeation, many bearing-wall structures have gable ends.

The shape of the gable and how it is detailed are determined by such things as the structural system used, material availability and aesthetic concerns.

Flashing:

Flashing is used to prevent water from seeping into the cracks between roof coverings and other parts of the structure.

Hip:

Hip is formed when two sloped surfaces join to form a ridge with an outward angle of more than 180°.

Ridge:

The ridge of a roof is the horizontal intersection where two roof surfaces meet.

Purlins:

Purlins are horizontal members that help to provide support to the principal rafters in a wall-to-wall roof. Purlins need to be painted before they are set into place, so as not to get damaged during installation.

Fascia:

Upon fascia, the materials that cover the lowermost roof rests.

Rafter:

A rafter is the horizontal structural component along the top of a gable roof that extends from the support to the ridge. Multiple rafters are used side by side, with one between each purlin.

In addition to common rafters, hip rafters, jack rafters, and valley rafters, you can use steel rafters to frame the roof.

Battens:

Battens are attached to common rafters or on the top of ceiling boards and are thin strips of wood. They are also made of metal or plastic.

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Advantages and Disadvantages of Gable Roof:

After the Types of Gable Roof we should focus on The advantages and Disadvantages of gable roofs which are explained below;

Advantages of Gable Roof:

Provide more space:

A homeowner can gain more space with this type of roof, which has a sloped or triangular design.

There is an additional attic space and better ventilation throughout the property.

Affordable:

Building with wood is simpler, so the overall cost and installing of a building made of wood is lower than the cost of other types of buildings.

Reliable Water Drainage:

As a result of its sloped design, this type of roof has an efficient drainage system and can minimize the risk of leaks.

This is because rain and snow can easily slide off and will ensure that your roof lasts longer.

Variety of Material Options:

When building, many material options are available. Concrete tiles, clay tiles, and metal sheets can all be used in construction.

Disadvantages of Gable Roof:

Needs to Be Properly Installed:

It is important to install a gable roof properly with the right materials and supported by adequate framing so that it can last for many years.

Prone to Damage from the Wind:

If there is a hurricane during any time of the year, this type of roofing is not recommended.

Vulnerable:

If anyone lives in areas with stable weather, this roof is suitable for them to use. But if they lived in a place that has extreme weather, the construction of the roof could collapse if hit by strong winds.

Easy to Crack:

As it is composed of a frame and a tile roof, you need to be aware that the roof is exposed to sun and rain.

This roof is easily cracked and must be repaired. Adding heat-resistant and waterproof coatings to the roof will make it more durable.

Pay Attention to Water Loads:

The sloping shape of a gable roof makes it less likely for water to leak into the house, but if the slope is too gentle, then the roof will collapse under heavy rain.

If a roof’s slope is low, the roof is more vulnerable to collapse. A high angle for the slope of the roof should be made so that this does not happen.

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Cost of Gable Roofing Construction:

Generally, the cost of building a roof averages anywhere from $8 to $16 per square foot. A roof of 1,000 square feet would cost anywhere from $8,000 to $16,000. Additional gables and dormers increase the cost.

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How Long Can The Roof Last?

The longevity of a roof is determined by how effectively it was installed and the materials used. A correctly fitted roof can survive for 40 years on average, and even longer if the supporting framework is suitable.

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The post Gable Roof | Types of Gable Roof | Parts Advantages & Disadvantages appeared first on The Civil Engineering.

Structural Load Calculation | Load Calculation on Beam, Colum, Slab, Wall and Staircase | Size Calculation for Footing or Foundation:

In a frame-type structure, we must know about the various loads that may be coming on the columns, beams, or slabs. calculate load on beam column wall slab and staircase, structural calculation
The frame structure transfers the load from the slab to beam, from beam to column, and finally to the foundation of the building. structural load calculation

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Definition of Load in Construction:

The stress on a beam, joint, slab, column, etc. The load is the most important consideration when designing structural elements.

It can be a live load or a dead load.

When loads are applied to structures, they undergo deformations and displacements, which can cause stresses.

What is Beam?

The Beam is a horizontal structural member in building construction that carries shear force, bending moment, and transfers loads to columns on both ends of it.

The bottom of the beam experiences tension and the top experiences compression. Therefore, more steel is used at the bottom than at the top. structural load calculation

What is Column?

A column is a vertical structural member that supports loads from above. For example, a column might support the weight of a ceiling, floor or roof slab or support the weight of a beam.

It is a Compression member, We use columns to hold up buildings and other structures. They can be made of steel, reinforced concrete, wood, or composite materials. The column’s cross-section can take any shape that’s necessary for the load it must sustain.

What is Slab?

A slab is a flat horizontal surface, such as the floor of a building, that is supported by beams and columns. A slab is usually several inches thick and can be created by pouring concrete over other materials.

Concrete slabs can be poured on-site or off-site or maybe poured in-situ using formwork, but they are typically poured on-site. If reinforcement is required, the concrete can be pre-stressed or rebar can be placed within the formwork before the concrete is poured.

Load Calculation Procedure on Slab:

When you are calculating load on slab, you have to first check whether it is a one way slab or two way slab structural load calculation

How to check weather’s its one way or two way :

If the ratio of longer span to shorter span is greater than 2 then the slab is considered as one way and if its less than 2 then this slab will be two way slab.

or in simple terms, structural load calculation

L (length) / B (breath) > 2 , then its a One Way Slab and

L / B < 2 then its a Two Way Slab. calculate load on beam

The picture attached below shows the load distribution pattern in one way slab and two way slab. structural load calculation

For one way slab : The formula for load distribution is (Lx/2) x W, where Lx is the shorter span and W is the load (self weight of beam + weight of the wall above the beam + live load on slab). calculate load on beam

Whereas for two way slab, the load distribution pattern follows 2 trapezoid and 2 triangles, so the formula splits into

Triangle region : [(Lx * W)/3] calculate load on beam

Trapezoidal region : [ ((Lx * W)/6) (3 – (Lx/Ly))^2]

Load Transfer Mechanism:

The dead load and live load on the structure acts on the slab are efficiently transferred from slab to beams, which in turn transmit the loads to columns. The columns then transmit the loads to the supports and finally to the underlying earth through the foundation.

Types of Load Acts on Building:

There are mainly two categories of load acts on building structure:

1. Gravity Loads – Which act in a downward direction, for example Dead Load and Live Load calculate load on beam
2. Lateral Loads – Which acts in horizontal direction, for example Wind Loads and Earthquake Loads. calculate load on column

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Types of Load on Column Beam Slab and Wall:

1) Column Self Weight X Number of floors

2) Beams Self Weight per running meter

3) A load of walls per running meter

4) The total load on Slab (Dead load + Live load + Self-weight)

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Structural Load Calculations for Building:

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Specification of Structural Elements:

As per the given house plan: calculate load on column

Thickness of Slab = 130 mm (5″)

Size of All Beams = 230mm x 300mm (9″ x 12″)

Size of All Columns = 230mm x 300mm (9″ x 12″)

Size of flooring = We will calculate the size of footing based on load coming on building

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Load Calculation on Slab:

1. Dead Load:

Self Weight of Slab = Slab Thickness x Unit weight of RCC

Self weight of Slab = 0.13 m x 25 KN/m³ = 3.25 KN/m²

calculate load on column

Floor Finish Load on Slab = usually we take (1 – 1.5 KN/m²)

Partition Wall Load on Slab = usually we take 1 KN/m²

Waterproofing Material Load = usually we take 1 KN/m²

calculate load on column

Total Dead Load o Slab = 3.25 + 1.5 + 1 + 1 = 6.75 KN/m²

2. Live Load:

Live Load on Slab for residential building = 2 – 3 KN/m²

Total Load on Slab:

Dead Load on Slab = 6.75 KN/m² 

Live Load on Slab = 3.0 KN/m²

Total Load on Slab = 6.75 + 3.0 = 9.75 KN/m²

Total Load on Slabs (All building Slabs) = 9.75 x 2 = 19.5 KN/m² (where take 2 for G+1 Story) calculate load on column

Consider Factor of Safety = 1.5

Total Factored Load on Slab = 1.5 x 19.5 = 29.25 KN/m²

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Load Calculation on Staircase:

Thickness of waist Slab = 150 mm

Riser = 150 mm calculate load on staircase

Tread = 250 mm

For Going:

Self weight of waist Slab = waist slab thickness x unit weight of RCC x [{sqrt(R2) + sqrt(T2)}/T] calculate load on slab

Self weight of waist Slab = 0.15m x 25 KN/m³ x [{sqrt(0.152) + sqrt(0.252)}/0.25]

Self weight of waist Slab = 4.37 KN/m²

Self weight of Steps = R/2 x 25 = 0.15/2 x 25 = 1.875 KN/m²

Floor Finish Load on Staircase = 1.0 KN/m²

Live Load on Staircase = 3.0 KN/m²

Total Load on Going = 4.37 + 1.875 + 1.0 + 3.0 = 10.25 KN/m²

Ultimate Load on Going = 1.5 x 10.25 = 15.36 KN/m²

For Landing:

Self weight of landing = Thickness of landing slab x density

Self weight of landing = 0.15 x 25 = 3.75 KN/m²

Floor finish load on staircase = 1.0 KN/m²

Live Load on Staircase = 3.0 KN/m²

Total Load on Landing = 3.75 + 1.0 + 3.0 = 7.75 KN/m²

Ultimate Load on Landing = 7.75 x 1.5 = 11.625 KN/m²

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Load Calculation on Beam:

1. Dead Load:

Self weight of Beam = Size of Beam x unit weight of RCC

Self weight of Beam = (0.23 x 0.30)m x 25 KN/m³ x 2 = 3.45 KN/m (Where 2 is taken for G+1 Story) calculate load on slab

Wall Load on Beam = Thickness of Wall x Height x Unit weight of material

Main Wall Load on Beam = 0.23m x 3m x 19 KN/m³ = 13.11 KN/m

Partition Wall Load on Beam = 0.1m x 3m x 19 KN/m³ = 5.7 KN/m

Parapet Wall Load on Beam = 0.2m x 1.2m x 19 KN/m³ = 4.56 KN/m

Wall Plastering Load on Beam = 0.012m x 3 x 2 x 20.4 KN/m³ = 1.468 KN/m

Load on Beam 1:

Total Load on Beam 1 = Self weight + Main wall Load + Parapet wall Load + Wall Plastering Load + Load from Slab (trapezoidal load) calculate load on slab

Total Load on Beam 1 = (3.45 + 13.11 + 4.56 + 1.468 + 40.71) KN/m

Total Load on Beam 1 = 63.29 KN/m calculate load on wall

Total Factored load on Beam 1 = 1.5 x 63.29 = 94.95 KN/m

Load on Beam 3:

Total Load on Beam 3 = Self weight + Main wall Load + Parapet wall Load + Wall Plastering Load + Load from Slab (trapezoidal load) calculate load on slab

Total Load on Beam 3 = (3.45 + 13.11 + 1.468 + 35.685 + 35.685) KN/m

Total Load on Beam 3 = 89.39 KN/m calculate load on wall

Total factored Load on Beam 3 = 1.5 x 89.39 = 134.09 KN/m

Total factored load on Beam 2 and 5 = 1.5 x 58.26 = 87.40 KN/m

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Load Calculation on Column:

Load on Column 1:

Self weight of column = size of column x height x unit weight

Self weight of column = (0.23 x 0.3)m x 3m x 25 KN/m³ x 2 = 10.35 KN (where 2 is taken for G+1 Story) calculate load on slab

Total factored load on Beam 1 = 94.95 KN/m

Total factored load on Beam 2 = 87.40 KN/m

Load from Beam = Half Load from Beam 1 + Half Load from Beam 2

Load from Beam = (94.95 x 4.26/2) + (87.40 x 3.66/2) = 362.18 KN

Load on Column 1 = 10.35 KN + 362.18 KN = 372.53 KN

Load on Column 2:

Load from Beam = Half Load from (Beam 1 + Beam 5 + Beam 3)

Load from Beam = (94.95 x 4.26/2) + (87.40 x 3.66/2) + (134.09 x 3.66/2) = 607.57 KN

Load on Column 2 = 10.35 KN + 607.57 KN = 617.92 KN

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Size Calculation for Footing:

Size of Footing for Column 1:

Assume, SBC of Soil as 200 KN/m²

Load on Footing 1:

Load from Column 1 = 372.53/1.5 = 248.35 KN

Self weight of footing = 10% of unfactored column load

Self weight of footing = 10/100 x 248.35 = 24.83 KN

Total Load on Footing 1 = 248.35 + 24.83 = 273.2 KN

calculate load on slab

Area of footing = Total Load/SBC of Soil = 273.2/200 = 1.36 m²

calculate load on wall

If for square footing, we take length = breadth

size of footing L = B = sqrt(1.36) = 1.16m

calculate load on wall

If for rectangular footing,

Assume one side of footing (B) = 1.0 m Length of footing (L) = 1.36/1.0 = 1.36 = 1.4m (say) calculate load on staircase

Size of footing (L x B) = 1.4 m x 1.0 m

Size of Footing for Column 2:

Take SBC of Soil as 200 KN/m²

Load on Footing 2:

Load from column 2 = 617.92/1.5 = 411.95 KN

Self weight of footing = 10% of 411.95 = 41.19 KN

Total load on footing 2 = 411.95 + 41.19 = 453.14 KN

calculate load on staircase

Area of footing = Total Load/SBC of Soil = 453.14/200 = 2.26 m²

calculate load on staircase

If for rectangular footing,

Assume one side of footing (B) = 1.4 m

Length of footing = 2.26/1.3 = 1.60 = 1.6m

Size of footing 2 (L x B) = 1.6m x 1.4m

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Note:

To find the size of footing, load considered should be service load for isolated footing.

For any building to find the size of footing, use a combination of loads i,e

For Gravity loads, load combinations are,

1.0 (DL + LL) – Most critical combination is selected

1.5 (DL + LL) – Most critical combination is selected

In above example, we took 1.5 as factor of safety calculate load on staircase

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