Reinforcement Detailing of Beams from ETABS output

Aim:

Detail design of beams in Etabs 2018.
The ETABS file for a G+4 building is provided. Run the analysis and design of the RCC Moment ResistingFrame. The following challenge deals specifically with two continuous beams on the 1st floor.

1 ) 3 span continuous beam along grid A

2) 7 span continuous beam along grid 3

Provide details of longitudinal and shear reinforcement for the two continuous beams. Sketch the beam elevation details or draft it using AutoCAD software.

Introduction :

*The design and construction of reinforced concrete buildings shall be governed by the provision of

IS 456:2000

* steel reinforcement of grade Fe 415 or less can be used

*strong steel is not preferable to low strength steel in earthquake-prone regions because the typical stress-strain curve of low steel shows the following advantages a) long yield b) greater breaking strain c ) less strength gain after the first yield.

Longitudinal Reinforcement :

* the top as well as the bottom reinforcement shall consist of at least two bars throughout the member length

*Analysis needs to be done

*Concrete design is done for this model

** 3 span continuous beam along grid A

At the top:

Maximum at end support 2046 mm^2

Minimum at end support 938 mm ^2

Ast for 32 diameter = 804 .24

Ast for 25 diameter = 490

Ast for 20 diameter= 314

Ast for 16 diameter = 201

Ast for 12 diameter = 113

Maximum at the mid supports is 511 mm^2

** 2 bars of diameter 32mm and 1 bars of 25 mm satisfies the overall Ast

2 x T32 = 1608 mm ^2

T25 = 490 mm^2

2 X T32 + T25 = 2098 mm ^2

or

** 3 bar of diameter 32 mm satidfies the overall Ast

3 T32 = 2412 mm ^2

At the bottom :

Maximum at the end support is 1945 mm ^2

Maximum at the mid support is 789 mm ^2

** 2 bars of diameter 32 mm and 1 bar of 25 mm satisfies the overall Ast

2 x T32 = 1608 mm ^2

T25 = 490 mm^2

2 X T32 + T25 = 2098 mm ^2

or

**2 bars of diameter 32 mm and 1 bar of 20 mm satisfies the overall Ast

2 x T32 = 1608 mm ^2

T20 = 314 mm^2

2 X T32 + T20 = 1922 mm ^2

1)

Or :

2)

7 span continuous beam along grid 3

At the top :

**Maximum at end supports is 1940 mm ^2

**Maximum at Mid supports is 485 mm ^2

** 2 bars of diameter 32 mm and 1 bar of 25 mm satisfies the overall Ast

2 x T32 = 1608 mm ^2

T25 = 490 mm^2

2 X T32 + T25 = 2098 mm ^2

At the bottom :

** Maximum at end supports is 1105 mm^2

** Maximum at mid supports is 1501 mm^2

** 2 bars of diameter 32mm satisfies the overall Ast

2 X T32 = 1608 mm ^2

Shear details :

Shear details ( from etabs software )