Reinforcement Detailing of Beams from ETABS output

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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.

Aim :-

To provide reinforcement details for beam using ETABS

Introduction :-

• Beam re horizontal structure elements for supporting lateral loads
• In conventional reinforced concerte structures, beams usually receive load from floor slab, but may also be subjected to other load such as wall loads, finishes, services installation etc.
• The design and detailing of RC beam include of selection of proper beam size and quality of longitudnal and shear reinforcement that will satisfy servicibility limit state requirements.
• Afterwrds, its very important that beam reinforcement are placed and arranged properly on site, to aviod constrction error.

Procedure :-

• Download the given model and open it into ETABS.
• Click to conctrete frame design
• Select the design conbination
• Click the concrete frame option
• Run the analysis

• Check the load combination as attached below

• Check or Start design as shown below

• Display Design info as shown below

• Longitudnal reinforcement will appear as shown below

• Check the values of percentage steel

• At Grid-3

At the top

a. Max Ast at middle =485

b. Max Ast at support = 194

Therefore, provide 2 dia of 32mm bars and 1mm of 25mm bars

At the bottom

a. Max Ast at middle =1056

b. Max Ast at support = 1501

Therefore, provide 3 dia of 25mm bars and 1mm of 16mm bars

• At Grid-A

At the top

a. Max Ast at middle =477

b. Max Ast at support = 2045

Therefore, provide 2 dia of 32mm bars and 1mm of 25mm bars

At the bottom

a. Max Ast at middle =1927

b. Max Ast at support = 789

Therefore, provide 2 dia of 25mm bars and 1mm of 16mm bars

• Design Shear deatils

Result :-

• The beam are designed succesfully in detail from EATBS software.
• Provided the details of longitudnal and shear reinforcement for two contineous beams.
• And also calculated the value of maximum shear force in the contineous beams using EATBS Software.