Bar Bending Schedule Calculation - PDF

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					Exercise No. 3                                                                               Estimating And Costing




                                             Exercise No. 3
1.0    Title:
       TAKING OUT QUANTITIES FOR SMALL R.C.C. STRUCTURE SUCH AS HALL.

2.0    Prior Concept :
       Units of measurements of various items of work.

3.0    New Concepts :
       3.1       Propositions
                 Proposition 1 : Length of straight Bar with Hooks at both ends




                                                                                                     S = End cover



                                                   L = Clear span

                                                   FIGURE 3.1                      b = End Bearing
                                                   Fig. of Beam

       Length of straight Bar (main)          = Clear span + 2X (End Bearing) - 2 X End cover+2 X 9d
                                              = ( L +2 X b ) -2 X s + 2 X 9d, where d is diameter of bar.
       Proposition 2 = Length of Bent up Bar with hooks at both ends




                                                    FIGURE 3.2
             Additional length due to inclination = 1.414x - x = 0.414x
       .'. x = center to center distance between top portion & bottom portion of bars.
             = Total depth of beam - (Top & Bottom cover) - half dia. of main bar at top - half dia. of main
             bar at bottom
       Length of bent up bar     = length of straight Bar + 2 (Additional length due to inclination)
                                 = ( L +2 X b ) -2 X s + 2 X 9d +2X 0.414x
       Proposition 3 :- Length of stirrups (Mild Steel)
            Depth of stirrups = Total Depth - Top cover - Bottom Cover
            Width stirrups     = Total width - 2 (Side cover)
            Length of stirrups = 2 (Depth of stirrups) +
                                 2 (Width of stirrups) +
                                 Length of hook (15 cm / 24 x Φ)
                                 where Φ - diameter of bar
       Proposition 4 :- Number of stirrups
                                            Total length - 2 x end cover
                       No. of stirrups = ---------------------------------------- + 1
                                                        Spacing




18 ♦                                                      MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION
Estimating And Costing                                                                               Exercise No. 3



       Proposition 5 :- Weight of bar
                   Weight of bar per running meter
                   = C/s Area of bar x density of bar
                   = (πΦ2) x 7850 kg/m3
                        4
                   = Φ2 Kg/m where Φ is in 'mm'
                      162
       Proposition 6 :- Quantity of Bar
       Quantity of Reinforcement = No. of Bars x Length of Bar x Wt of bar in Kg/m
       Note : Standard length of one Reinforcement bar = 12m
       Proposition 7 :- Lap length
                   Lap length in column = 45 Φ
                   Lap length in beam and slab = 69 Φ
                   Φ is in 'mm'
       Proposition 8 :- Quantity of Form work

       1)      For RCC Beam
               Quantity = (b+2d) x l      Sq. meter




       2)      For RCC Rectangular Column
               Quantity = 2 (l+b) x h Sq. meter




       3)      For RCC Circular Column
               Quantity = π x d x h Sq. meter


       3.2     General concept of structure :-




4.0    Learning Objectives:
       4.1     Intellectual Skills:
               (i)       To understand the procedure of calculation of quantities of steel, concrete & form
                         work.
       4.2     Motor Skills:
               (i)       To develop ability to calculate the quantities of steel, concrete , form work and entering
                         them in a measurement sheet.

MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION                                                               ♦ 19
Exercise No. 3                                                                         Estimating And Costing




5.0    Procedure :-
       1)        Study the given drawings carefully.
       2)        Finalise the items of the work with their units of measurements. Prepare the check list
                 of the items.
       3)        Write brief description of each item of the work on the measurement sheet.
       4)        Calculate length, width & depth of different components for calculation of quantity of
                 concrete & form work.
       5)        Calculate the quantity of form work for beam, column. (One sample).
       6)        Enter the length, width/breath & depth/height in measurement sheet for concrete & form
                 work item.
       7)        Prepare bar bending schedule.
       8)        Calculate the length of bars of different diameter in different components such as slab,
                 beam, column, footing etc.
       9)        Calculate the number of bars of different diameter in different components.
       10)       Enter the number, length & weight of bar for different bars in different components in Bar
                 bending schedule.
       11)       Calculate the quantities of items of the work in the measurement sheet.




20 ♦                                                  MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION
Estimating And Costing                                                      Exercise No. 3



6.0    Observation & Calculation

                         MEASUREMENT SHEET (Student to write description)

Name of work: …………...………………………………………………………………………………..............




MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION                                      ♦ 21
Exercise No. 3                                                       Estimating And Costing




                 MEASUREMENT SHEET (Student to write description)
Name of work: …………...………………………………………………………………………………..............




22 ♦                                    MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION
Estimating And Costing                                                      Exercise No. 3




                         MEASUREMENT SHEET (Student to write description)
Name of work: …………...………………………………………………………………………………..............




MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION                                      ♦ 23
Exercise No. 3                                                       Estimating And Costing




                 MEASUREMENT SHEET (Student to write description)
Name of work: …………...………………………………………………………………………………..............




24 ♦                                    MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION
Estimating And Costing                                                      Exercise No. 3




                         MEASUREMENT SHEET (Student to write description)
Name of work: …………...………………………………………………………………………………..............




MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION                                      ♦ 25
Exercise No. 3                                         Estimating And Costing




                 BAR BENDING SCHEDULE




26 ♦                      MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION
Estimating And Costing                                     Exercise No. 3




                                BAR BENDING SCHEDULE




                              Total Quantity =   Quintal




MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION                     ♦ 27
Exercise No. 3                                                                            Estimating And Costing



7.0    Result :-
       The quantities of each items of work are calculated and entered in measurement sheet against
       each item with their unit of measurement

8.0    Questions :-
       Note: Distribute 3-5 questions to each student for writing the answers in the manual.
       1)        A R.C.C. simply supported beam of size 280 mm x 620 mm is reinforced with 4 Nos. of 18
                 mm diameter main bars. Main bars are placed in one row and two bars are bent up. Two
                 anchor bars are provided at top and are of 12 mm diameter. 6 mm diameter stirrups are
                 provided at 150 mm c/c. The span of beam is 5.5 m and end bearing is 25 cm. Calculate the
                 total quantity of steel reinforcement.
       2)        Calculate the quantity of the formwork for the beam in Problem 1.
       3)        A R.C.C. simply supported slab of clear size 3.1 m X 6.3 m is reinforced with 12 mm
                 diameter bars with spacing of 12 cm c/c.. Alternate bars are bent up. Distribution steel is of
                 6 mm diameter with spacing of 14 cm c/c.Thickness of slab is 10 cm. Bearing of slab is 15
                 cm. I) Prepare bar bending schedule ii) calculate the quantity of reinforcement.
       4)        Calculate the quantity of formwork for the above problem.
       5)        Calculate the quantity of concrete for the beam in problem 1.
       6)        How Steel quantity is calculated by using percentages?
       7)        Compare the quantity of steel reinforcement for column footings calculated by bar bending
                 schedule and by percentages.
       8)        Compare the quantity of steel reinforcement for column calculated by bar bending schedule
                 and by percentages.
       9)        Compare the quantity of steel reinforcement for Beam calculated by bar bending schedule
                 and by percentages.
       10)       Compare the quantity of steel reinforcement for Slab calculated by bar bending schedule
                 and by percentages.

9.0    Answer :-




28 ♦                                                   MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION
Estimating And Costing                                   Exercise No. 3



                                   (Space for Answers)




MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION                   ♦ 29

				
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