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 carefully plan the beams using the Etabs 2018 data.
• To give specifics about the shear and longitudinal reinforcement for the two continuous beams that are given.
• In order to determine the maximum shear force in each span of the continuous beams.

INTRODUCTION:

• The horizontal structural components that support lateral loads are called beams.
• Beams in traditional reinforced concrete structures are typically loaded by the floor slab, although they can also be loaded by wall loads, finishes, the installation of services, etc.
• The right beam size and the amount of longitudinal and shear reinforcement are chosen during the design and detailing of RC beams in order to meet serviceability limit state and ultimate criteria.
• After then, in order to prevent construction errors, it is crucial that the beam reinforcements are positioned and organised correctly on the job site.

PROCEDURE:-

Step1:

• We must first download the challenge and open the Challenge 7 page.
• Open the Challenge in etabs 2018 after downloading it, as demonstrated here.

Step2:

• Next we have to check the load combinations, as shown below.

Step3:

• Next we have to start the beam design by selecting the 'Start Design/Check' option, as shown below.

Step4:

• 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 the design output and click on the Ok button, as shown below.

• Next the longitudinal reinfoorcement details will appear, as shown bwlow.

Step5:

• Next, we must supply the reinforcement information and build the reinforcement diagram for the three-span continuous beam along Grid-A.
• The bottom support's greatest altitude is 1766 mm2, and the lower middle is 702mm2.
• Maximum Ast values for the top support and top middle are 1889 m m 2 and 453 m m 2, respectively.
• We now supply 3-28 Φ at both the top and bottom, as the picture below illustrates.
• Next, as indicated below, we supply 1–8 Φ as top supports for the continuous beam.

Step6:

• Next, we must supply the reinforcement information and build the reinforcement diagram for the seven-span continuous beam along Grid-3.
• The bottom support's maximum Ast is 1061 mm2,and 1493 mm2 in the lower middle.
  
  
• Maximum Ast values for the top support and top middle are 1915 mm 2 and 479 mm 2, respectively.
• We are now providing 3-22 Φ at both the top and bottom, as the image below illustrates.
• Then, as indicated below, we supply 1-10Φ and 1-12 Φ for the top supports and 2-16 Φ for the bottom middle of the continuous beam.

Step7:

• Once the details for the beam reinforcement have been entered, we select the beam and do a right-click on it, which causes the new tab to display as seen below.
• Next, as indicated below, we must select the Details option from the Concrete beam design menu.

• Next the shear details will be visible, as shown below.
• As per the clause 6.3.3 the design force is 232kN.
• We got, maximum shear force=174.11kN.

Result:

• The Etabs software effectively creates a detailed design for the beams.
• Supplied information on the two continuous beams' longitudinal and shear reinforcing.
• Additionally used the Etabs software to determine the maximum shear force in the continuous beams.