bar bending schedule of one way rectangular slab

A Bar Bending Schedule (BBS) is a critical document that outlines specific details regarding the reinforcing steel bars utilized in constructing a slab. This schedule encompasses crucial information such as bar sizes, lengths, shapes, and their designated positions within the structure.

Its meticulous preparation plays a pivotal role in ensuring the precise and accurate placement of reinforcement during the construction process. Ultimately, the BBS significantly contributes to upholding the structural integrity and load-bearing capacity of the completed slab.

one way slab

A one-way slab is a specific type of reinforced concrete slab engineered to primarily resist bending along a single direction. It receives support from at least two sides and channels the load in one direction towards beams or supporting walls.

In the construction of a one-way slab, reinforcement is strategically placed along what is known as the shorter span. This reinforcement serves to counteract the tensile stresses generated by bending. Conversely, the longer span is typically left without additional reinforcement. This design proves most effective for situations where one side of the slab significantly exceeds the length of the other.

It’s crucial to ensure that the design and construction of one-way slabs adhere strictly to engineering standards and codes, guaranteeing their ability to safely bear the intended loads.

Details Included in the bar bending Schedule

Bar Numbering System

Each steel bar is assigned a unique identifier to facilitate organized tracking and placement.

Bar Size and Diameter

This section specifies the dimensions of each bar, including size and diameter, to adhere to precise engineering requirements.

Bar Shape and Configuration

Indications of whether the bars are to be used in their straight form or bent at specific angles to suit the structural design.

Cutting Length Determination

The schedule outlines the exact length at which each bar should be cut before undergoing the bending process and subsequent placement within the slab.

Bent Length and Configuration

Specifies the length and shape of the bends, ensuring they align with the structural specifications and blueprints.

Quantity of Bars

This section quantifies how many bars of a particular size and configuration are required for the construction of the slab.

Total Length Post-Bending

Provides the overall length of the steel bar after undergoing the bending process, taking into account any alterations in shape.

Tailoring the Schedule

It is imperative to acknowledge that the specific requirements for a bar bending schedule are contingent upon the unique design and engineering parameters of the project at hand. Collaborating with a seasoned structural engineer or a qualified professional is indispensable in crafting an accurate and customized schedule tailored to the needs of your rectangular slab construction endeavor.

slab plan
slab section

Given,

length = 3000mm

width = 1400mm

depth = 150mm

clear cover(cc) = 25mm

beam depth = 250mm

main bar = 16mm@200mm c/c

dist. bar = 12mm@200mm c/c

top extra bar = 8mm@200mm c/c

bends

45°=d

90°=2d

main cranked bar

main bar bar bending schedule

No. of bars = ((slab width – (2*cc))/spacing)+1

= ((1400-(2*25))/200)+1 = 7.75 ~ 8nos.

Cutting Length = slab width+((2*beam depth)-(2*cc))+(0.42*(slab depth-(2*cc)-bar dia))-(2*bends)

= 1400+((2*250)-(2*25))+(0.42*(150-(2*25)-16)-(2*2*16) = 1821.28 ~ 1822mm

weight = ((d^2/162)*CL)/1000= ((16^2/162)*1822)/1000=2.879 ~ 3Kg

Distribution bar

distribution bar

No. of bars = ((slab length – (2*cc))/spacing)+1

= ((3000-(2*25))/200)+1 = 15.75 ~ 16nos.

Cutting Length = slab length-(2*cc))

= 3000-(2*25) = 2950mm

weight = ((d^2/162)*CL)/1000= ((12^2/162)*2950)/1000= 2.62Kg

Top bars

Generally, extra bars are provided upto L/4 span of slab.

No. of bars = (slab length/4)/spacing)+1

= (((3000/4)/200)+1)*2= 9.5 ~ 10nos.

Cutting Length = (slab width/4)+Ld

= 1400+(48*8) = 1784mm

weight = ((d^2/162)*CL)/1000= ((8^2/162)*1784)/1000= 0.705Kg

bar bending schedule table

Sl. No.DescriptionBar Dia (mm)Spacing (mm)CL (mm)No. of bars Weight (Kg)
1main bar162001822824
2distribution bar1220029501642
3top bar82001784107.05

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