Reinforcement Detailing of Beams from ETABS output

Reinforcement Detailing of Beams from ETABS output

Question:

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.

Answer:-

Aim:

• To design the beam 
• To provide the rebar detailing for the beam

Stepwise procedure:-

• Open the attatchment file in ETAB software 
• 
• once the file open 
• go to the plan view option 
• select the FIRST 
• 
• click > apply > ok
• Click > RUN analysis
• 
• Now, click> design tab> concrete frame design
• 
• complete the design process
• 
• once the design finished 
• screen is shown as below (showing with the longitudinal reinforcement)
• click > design tab > concrete frame design > display design info
• one dialogue box will open 
• change the details as below
• 
• click > apply > ok
• it will shows as below
• 
• See in the above detail 
• The failed section is shown by red colour 
• Go with that 
• Right click with this beam 
• 
• click > details
• click > shear details

   1) 3 span continuous beam along grid A

Longitudinal reinforcement of beam at grid 3

Shear reinforcement of beam at grid 3

2) 7 span continuous beam along grid 3

Longitudial reinforcement of 7 span beam at grid 3

Shear reinforcement of 7 span beam at grid 3

 Rebar calculation and Detailing:

For 3 span beam at grid A

For 7 Span beam at grid 3: calculation and detailing

Calculation of shear force:

As per the IS13920-2016 (clause 6.3.3 b)

Reason of the Failure of middle span beam along grid A, possible way to Ressolve this failure

• Reduce the loading or increasing the loading
• Increasing the grade of concrete to increase the shear capacity of concrete

If we use higher grade of the concretefor that particular beam , it will increase the shear capacity and then we can make it pass