Reinforcement Detailing of Beams from ETABS output

Challenge 7 – Detailed design of concrete buildings -1

Detail design of beams in Etabs 2018.
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.

Ans:-

1) detail of beam

• longitudnal reainforcing

• shear rainforcement

• 3 span continuous beam along grid A

detail done using Auocad softwere

• 7 span continuous beam along grid 3

detail done using Auocad softwere

2)Provide reasons for failure of the middle span along grid A. What are the possible ways this issue can be resolved?

Reason:

O/S #45 the shear stress due to shear force and torsion together exceeds maximum allowed that’s why beam is failure

Suggestions:-

• Changing the grade of concrete to higher side
• Increasing the size of beam
• Reducing loads on the beam

3)Calculate value of the maximum shear force

As per is 456-2000 clause 40.4

Fy=415N/mm²

A_sv=151mm²

D=450mm

S_v=100mm

V_us=245KN :. Ok as per IS13920-2016