bar bending schedule of rectangular footing

A Bar Bending Schedule (BBS) for a rectangular footing provides detailed information about the type, size, quantity, and placement of reinforcing steel bars (rebars) in a rectangular-shaped concrete footing. Below is an example of a simplified BBS for a rectangular footing:

Rectangular Footing

Definition and Purpose

A rectangular footing serves as a crucial structural element tasked with the responsibility of distributing the load of a building or structure to the underlying soil. It is meticulously designed to bear vertical loads emanating from columns or walls, ensuring a secure transmission to the ground.

Characteristics and Considerations in bar bending schedule

Shape and Dimensions

Rectangular footings boast a configuration akin to a rectangle. Their specific dimensions—length, width, and depth—are meticulously calculated based on the anticipated loads and the bearing capacity of the supporting soil.

Load Distribution

The transfer of load from the superstructure to the footing is facilitated through columns or walls. this distribution mechanism allows the footing to evenly disperse the load across a wider expanse of soil.

Depth Considerations

The depth of a rectangular footing is judiciously determined, taking into account critical factors such as the bearing capacity of the soil and the magnitude of the loads it is expected to carry.

Reinforcement Strategies

To augment their strength and durability, rectangular footings may be fortified with steel bars, commonly referred to as rebars. This reinforcement is strategically implemented in accordance with the specific design and structural requisites.

Choice of Construction Materials

Typically fashioned from concrete, the composition of the material used for rectangular footings is meticulously determined by the structural engineer, adhering to precise design specifications and strength requirements.

Varieties of Rectangular Footings

A diverse array of rectangular footings exists, each tailored to distinct applications. These include isolated footings (for individual column support), combined footings (supporting multiple columns), and strap footings (linking two or more footings).

Pre-Design Soil Assessment

Prior to the actual design phase, a comprehensive geotechnical investigation is conducted. This crucial step serves to evaluate the pertinent properties and bearing capacity of the soil at the designated construction site.

Reinforcement Detailing with BBS

The intricate arrangement and configuration of reinforcement bars within the footing are meticulously outlined in a Bar Bending Schedule (BBS). This comprehensive schedule ensures not only the provision of adequate strength but also the precise distribution of loads.

Alignment and Leveling Imperatives

Ensuring proper alignment and levelness during the construction process is of paramount importance. This meticulous attention to detail guarantees a stable and robust foundation to support the superstructure effectively.

In summation, the rectangular footing stands as a foundational pillar in structural engineering, providing the essential groundwork for the stability and longevity of a building or any other engineered structure. Its design and construction demand a comprehensive understanding of various factors, ultimately culminating in a secure and reliable support system.

bar bending schedule

footing plan  bar bending schedule of footing
footing section

Given,

length = 3000mm

width = 1800mm

depth = 300mm

clear cover(cc) = 50mm

top & bottom main bar = 16mm@250mm c/c

top & bottom dist. bar = 12mm@250mm c/c

bends

45°=d

90°=2d

Calculation of bottom main & dist. bar

top footing bar

main bar

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

= ((1800-(2*50))/250)+1 = 7.8 ~ 8nos.

Cutting Length = (footing width-(2*cc))-(2*bends)

= 1800-(2*50)-(2*2*16) = 1636mm

weight = ((d^2/162)*CL)/1000= ((16^2/162)*1636)/1000= 2.585Kg

distribution bar

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

= ((3000-(2*50))/250)+1 = 12.6 ~ 13nos.

Cutting Length = (footing length-(2*cc))-(2*bends)

= 3000-(2*50)-(2*2*12) = 2852mm

weight = ((d^2/162)*CL)/1000= ((12^2/162)*2852)/1000= 2.535Kg

Calculation of top main & dist. bar

main bar

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

= ((1800-(2*50))/250)+1 = 7.8 ~ 8nos

Cutting Length = (footing width-(2*cc))-(2*bends)

= 1800-(2*50)-(2*2*16) = 1636mm

weight = ((d^2/162)*CL)/1000= ((16^2/162)*1636)/1000= 2.585Kg

distribution bar

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

= ((3000-(2*50))/250)+1 = 12.6 ~ 13nos

Cutting Length = (footing length-(2*cc))-(2*bends)

= 3000-(2*50)-(2*2*12) = 2852mm

weight = ((d^2/162)*CL)/1000= ((12^2/162)*2852)/1000= 2.535Kg

bar bending schedule

Sl. No.DescriptionBar dia (mmSpacing (mm)CL (mm)No. of barsWeight (Kg)
1Bottom main bar162501636820.68
2Bottom distribution bar1225028521332.96
3Top main bar162501636820.68
4Top distribution bar1225028521332.96

Notes:

All rebars used should conform to the relevant Indian or international standards for reinforcement steel.

The BBS should be prepared by a qualified structural engineer or an expert in structural detailing.

The provided dimensions, grades, and reinforcement details are for illustrative purposes only. In an actual construction project, these details would be determined by the structural engineer based on the specific requirements of the design.

It is crucial to adhere to local building codes, regulations, and standards while preparing and implementing a Bar Bending Schedule.

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