Reinforcement Detailing of Beams from ETABS output

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.

After apply shear reinforcing in design output (Shift+Ctrl+F6)

Shear Reinforcement of Beam at grid -3 from Etabs (cm2/1000mm)

• 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:

• Next we need to draw the Reinforcement diagram of 3 span continuous beam along Grid-A, and also need to provide the reinforcement details.
• The maximum Ast for the bottom support is 1766mm2 and bottom middle is 702 mm2.
• The maximum Ast for the top support is 1889mm2 and top middle is 453mm2.
• Now we provide 3-28Φ at the top and bottom, as shown in the below figure.
• Next we provide 1-8Φ at the top supports for the continuous beam, as shown below.

• 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.

1). For Sway Shear Force Right 2) For Sway Shear Force Left

Mas = 174 KNm Mah = 234 KNm

Mbb = 293 KNm Mbs = 155 KNm

La = 4.725m Lab = 4.725 m

Vd+L = 92 KN Vd+L = 70 KN

Vu,a = 46 KN Vu,a = 185 KN

Vu,b = 230 KN Vu,b = 45 KN

Load Combinations :-

Existing shear capacity in beam as per drawing :

Vus = 0.87fy Asv d / Sv

Given Data

Fy = 415 N/mm2

Asv = 151 mm2

d = 450 mm

Sv = 100 mm

Vus = 245 KN

Hence shear rebar in drawing is Okay As Per IS-13920 Code guideline.