Reinforcement Detailing of Beams from ETABS output
Que :-
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 design the beams in detail from the Etabs 2018.
To provide details of longitudinal and shear reinforcement for the given two continuous beams.
To calculate the value of maximum shear force in any one of the spans in the continuous beams.
Introduction:-
- Beams are horizontal structural elements used for the supporting lateral loads.
- In conventional reinforced concrete structures, beams usually receive load from the floor slab, but may also be subjected to other loads such as wall loads, finishes, services installation, etc.
- The design and detailing of RC beams involves the selection of the proper beam size and the quantity of longitudinal and shear reinforcement that will satisfy ultimate and serviceability limit state requirements.
- Afterwards, It is very important that the beam reinforcements are placed and arranged properly on site, to avoid construction error.
Procedure:-
Step:-1
- First we have to open the challange 7 page and download the challenge.
- After downloading the Challenge open it in the etabs 2018, as shown below.
Step:-2
- Next we have to check the load combinations, as shown below.
Step:-3
- Next we have to start the beam design by selecting the 'Start Design/Check' option, as shown below.
Step:-4
- After the completion of the beam design, we need to select the 'Display Design Info' option, as shown below.
- After selecting the 'Display Design Info' option the new tab appears, In that we select the Longitudinal Reinforcing in the Design Output and click on the OK button, as shown below.
- Next the longitudinal reinforcement details will appear, as shown below.
Step:-5
- Next we need to draw the Reinforcement diagram of 3 span continous beam along Grid-A, and also need to provide the reinforcement details.
- The maximum Ast for the bottom support is 176 mm2mm2 and bottom middle is 702 mm2mm2
- The maximum Ast for the top support is 1889mm2mm2 and top middle is 453 mm2mm2
- Now we provide 3-ΦΦ at the top and bottom, as shown in the below figure.
- Next we provide 1-8ΦΦ at the top supports for the continuous beam, as shown below.
Step:-6
- Next we need to draw the Reinforcement diagram of 7 span continous beam along Grid-3, and also need to provide the reinforcement details.
- The maximum Ast for the bottom support is 106 mm2mm2 and bottom middle is 1493 mm2mm2
- The maximum Ast for the top support is 1915mm2mm2 and top middle is 479 mm2mm2
- Now we provide 3-22ΦΦ at the top and bottom, as shown in the below figure.
- Next we provide 1-10ΦΦ and 1-12ΦΦat the top supports and we provide 2-16ΦΦ at the bottom middle for the continuous beam, as shown below
Step:-7
- After providing the beam reinforcement details, we select the beam and right click on the beam then the new tab appears, as shown below.
- Next we need to click on the Details option in Concrete beam design tab, as shown below.
- Next the Shear details will be visible, as shown below.
- As per the clause 6.3.3 the design force is 232 kN.
- We got, Maximum Shear force = 174.11 kN.
RESULT:-
- The beams are designed successfully in detail from the Etabs software.
- Provided the details of longitudinal and shear reinforcement for the two continuous beams.
- And also calculated the value of maximum shear force in the continuous beams using the Etabs software.