BBS (Advance Bar Bending Schedule)
Bar bending schedule or schedule of bars is a tabular representation of reinforcement bar. It is generally represented for each type of R.C.C work.
With the help of bar bending schedule the requirement of different length and sizes of bars may be known and can be arranged and bent-up during the time of construction.
Bar bending schedule generally describes the particulars of bars, shape of bending with sketches and total length and weight of the bars along with their numbers.
Bar bending schedule is generally prepared while estimating a R.C.C work or structure.
Applications
From 1950 to 2019 lots of modifications and enhancements happening in our world. In 1950, three-storeyed buildings are high rise buildings now we are constructing a building with 200 floors+. There is a massive growth in the construction industry. Due to the vast increase in world population demands increased facilities, more need for space and more construction.
Father of Estimation B.N. Datta has given certain recommendations for the usage of steel in different components of buildings. But, he didn’t mention any values if we use more bars in a single structural member.
Course Highlights:
Introductory phase covers, Reinforcement, its necessity.
Bar bending Schedule for each Structural Elements such as:
BBS of Footing
BBS of Column
BBS of Beam
BBS of one-way slab
BBS of Two-way slab
BBS of Staircase
BBS of Pile and pile cap
BBS of Sunken slab
Finding out cutting length and No. of Bar for Structural Members by Manual Calculation.
Technical Feature
In reinforced concrete structures, the reinforcement is surrounded by the sufficient concrete cover to protect the concrete from atmospheric conditions which makes concrete to corrode.
The distance is measured in different ways, and these have different terms like Clear Cover, Nominal Cover and Effective Cover.
- Clear Cover
- Nominal Cover
- Effective cover
Bar Bending schedule plays a vital role in the construction of High rise buildings. It is very important to learn Bar Bending Schedule for finding out the quantities of Steel reinforcement required for every component of the building.
For Suppose, consider the case of high rise buildings, It requires tons of steel to complete 10+ floor building. It’s impossible to order all the steel required for whole construction at a time it creates a problem of space and also steel is prone to corrosion by the contact of water (rain). To avoid this, high rise building orders reinforcement (steel) as per requirement. Firstly they find the Estimation of Steel reinforcement in footings (steel quantities) [Bar Bending Schedule for footings], required for the construction of footings. After the completion of footings they go for next order and so on.
- Deduct the concrete cover to find the dimensions of bars.
- Find the Length of single X Bars & Y Bars
- Find the total length of X bars. & Y bars
- Calculate the weight of steel required per 1m
- Calculate the total number of 12m bars required
- Find the total weight of steel required.
Bar bending schedule for floor columns. The part of the column which projected towards the sky on the superstructure is called Floor columns. And the part of the column which is inside of substructure is called Neck column.
- Find the length of the single main bar
- Find the total length of the Main reinforcement
- Calculate the weight of steel required per 1m of Main reinforcement
- Find out the total weight of steel required for Main reinforcement
- Deduct the concrete cover from all sides of ties and find out the length of stirrup using formulae.
- Obtain the total number of ties required using formula
- Find out the total length of ties required
- Calculate the weight of steel required per 1m of longitudinal reinforcement.
- Find out the total weight of steel required for longitudinal reinforcement
One way slab is a slab which is supported by beams on the two opposite sides to carry the load along one direction. The ratio of longer span (l) to shorter span (b) is equal or greater than 2, considered as One way slab because this slab will bend in one direction i.e in the direction along its shorter span
Due to the huge difference in lengths, the load is not transferred to the shorter beams. Main reinforcement is provided in shorter span and distribution reinforcement in a longer span.
Two way slab is a slab supported by beams on all the four sides and the loads are carried by the supports along with both directions, it is known as two way slab. In two way slab, the ratio of longer span (l) to shorter span (b) is less than 2.
In two way slabs, the load will be carried in both the directions. So, the main reinforcement is provided in both directions for two way slabs.
Stairs provide access to the various floors of the building. The stair consists of series of steps with landings at appropriate intervals. The stretch between the two landings is called flight. The Space, where stairs are provided is called staircase.
To make it ease in understanding, I am calculating the quantities of a staircase by dividing into components.
Components of Staircase:-
Waist slab: Waist slab refers to a slab of the stair that is inclining from the floor slab to the landing slab.
Flight: The series of steps between floor and landing.
Landing : The level of floor between flight.
Step: The step consists of Riser and tread.
Tread: The tread is the flat part that you step on.
Riser: The riser is the vertical(up and down) part between each tread in the stairway.
- Find the length of X Bar & Y bar
- Find the No. of X Bars & Y bars
- Evaluate the total length of X Bars & Y Bars
- Find out the total weight of steel required.
The slab which is provided below the washrooms to hide the sewage pipes or sewerage pipes is called Sunken slab. In this type, the pipes that carry water are concealed below the floor. Special care has to be taken to avoid leakage problems. After casting sewage pipes in the slab the slab is filled with coal or broken pieces of bricks. There are two types of sunken slab.
The slab which is provided below the normal floor level at a depth of 200mm to 300 mm and filled with broken pieces of bricks is called Sunken slab.
or
The Slab which is provided above the normal floor level at a height of 200mm to 300mm and filled with coal or broken pieces of bricks called Sunken slab.
Bar Bending Schedule is termed as “Calculation of the total Steel required for the construction of a building” We use steel to make concrete to be reinforced and for tension requirements. But how much steel required for constructing 15 floors building? How much Steel I have to order? All these questions are answered in BBS
In Bar bending schedule, the bars are organized for each structural units (Beams or columns or slabs or footings etc) and detailed list is prepared which specifies the Bar location (Bar in footings, slabs, beams or columns), Bar Marking (to identify the bar in accordance with the drawing), Bar Size (length of the bar used), Quantity (No. of Bars used), Cutting length, Type of Bend and Shape of the bar in reinforcement drawings.
1. Hook Length or Cutting length of Stirrups:-
2. Bend Length:-
3. Overlap Length / Lap Length in Reinforcement:-