Reinforcement Detailing of Beams from ETABS output
AIM:
Detail design of beams in Etabs 2019.
The ETABS file for a G+4 building is provided. Run the analysis and design the RCC Moment ResistingFrame. The following challenge deals specifically with two continuous beams in the 1st floor.
1) 3 span continuous beam along grid A
2) 7 span continuous beam along grid 3
Address the following issues thereafter.
• Provide details of longitudinal and shear reinforcement for the two continuous beams. Sketch the beam elevation details or draft it using autocad software. A sample of how beam elevation details is prepared in consultancy firms is provided below. Participants can prepare it as per their preference:
• Provide reasons for failure of the middle span along grid A. What are the possible ways this issue can be resolved?
• Calculate value of the maximum shear force in any one of the spans in both the continuous beams, as per clause 6.3.3 (b) in IS 13920 – 2016. Also, confirm these values from shear force demand calculated by ETABS.Please note that if longitudinal reinforcement provided is more than required (as per ETABS results), the shear force demand will vary from what is provided by ETABS.
Procedure:
1)Now open the privious model given in the question, click the Concrete frame design
tool in toolbar and Select design combinations
2)Select the appropriate combination from the dialogue box shown in display.
3)Now Click on concrete frame tab it starts checking the concrete design.
4) After the ANALYSIS is done OPEN the plan view in the plan view we can see the column and beam detailings.
5) Now to provide Grid 3 and Grid A reinforcement details.
Now grid A
At Top:
1) Maximum Ast at Support = 1889
2) Maximum Ast at Middle = 472.
3 bars of dia of 25mm = 1471.875
2 bars of dia of 16mm = 401.92
Total Ast provided=1889.765
Therefore, to satisfy the support we need to provide 3 bars of dia of 25 mm and 2 bars
of 16 mm dia.
Grid A:
At Bottom:
1) Maximum Ast at Support = 1766
2) Maximum Ast at Middle = 702
2 dia of 25mm -981.25
2 dia of 20mm =628
Total Ast provided=1810.21
Therefore, to satisfy the support we need to provide 2 bars of dia of 20 mm, 2 bars of 20mm and 1 bar of 16 mm.
GRID 3
At Top:
1) Maximum Ast at Support = 1915
2) Maximum Ast at Middle = 479.
*3 bars of dia of 20mm = 942
5dia of 16 mm = 1004.8
Total Ast provided=1946.8
Therefore, to satisfy the support we need to provide 3 bars of dia of 20 mm and 5 bars of 16
mm dia
At Bottom:
1) Maximum Ast at Support = 958
2) Maximum Ast at Middle = 1498
3 bars of dia of 20mm = 942
3 bars of dia of 16mm = 602.88
Total Ast provided=1544.8
Therefore, to satisfy the support we need to provide 3 bars of dia of 20 mm and 3 bars of 16
mm dia
RESULTS:
