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
As for 32 diameter = 804 .24
As 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 )