---
title: "Ductile detailing of beams and columns"
subject: "Design of RCC Structure"
chapter: 12
key: "semester_7/design_of_rcc_structure:ductile-detailing-of-beams-and-columns"
source: https://www.bctengineer.com/q/semester_7/design_of_rcc_structure/ductile-detailing-of-beams-and-columns
site: BCT Engineering
---

# Ductile detailing of beams and columns

Design of RCC Structure · Chapter 12: Introduction to Earthquake Resistant Design and Provisions for Ductile Detailing

- Asked in: 2074 Chaitra, 6 marks; 2080 Baisakh, 4 marks (asked 2 times)
- Video: [Ductile detailing of Beams as per IS-13920-2016 | detailing of beams |Beam detailing as per IS-13920](https://www.youtube.com/watch?v=OtGZM99vFLg) — Civil Engineering Mastery
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/design_of_rcc_structure/ductile-detailing-of-beams-and-columns
- Whole chapter: https://www.bctengineer.com/md/semester_7/design_of_rcc_structure/chapter-12

## Question

Explain briefly the ductile detailing requirements for beam and column with neat sketches.

## Short answer

Beam: b>=200 mm, b/D>=0.3, D<=L/4, continuous bars, closed stirrups at min(d/4,8phi,100 mm) over 2d, else d/2, splices in middle half. Column: min 200 mm, b/D>=0.4, special confining hoops at 75-100 mm over lo = max(D,h/6,450 mm), strong-column weak-beam so hinges form in beams.

## Answer

Ductile detailing makes the structure deform plastically in a controlled way during an earthquake without sudden collapse. IS 13920 governs the detailing of beams, columns and joints.

#### Beam
- $b \ge 200$ mm, $b/D \ge 0.3$, $D \le L/4$.
- Two bars continuous at top and bottom; $\rho$ between $0.24\sqrt{f_{ck}}/f_y$ and 2.5%.
- Bottom steel at a joint face $\ge 50\%$ of top steel.
- Splices in the middle half only, with hoops at 150 mm or closer.
- Closed stirrups with $135^\circ$ hooks. Within $2d$ of the support, spacing $\le \min(d/4,\ 8\phi,\ 100\text{ mm})$; elsewhere $\le d/2$.

#### Column
- Minimum size 200 mm, $b/D \ge 0.4$.
- Special confining hoops over $l_o = \max(D,\ h/6,\ 450\text{ mm})$ at each end, at 75-100 mm spacing and $\le b_{min}/4$.
- $135^\circ$ hooks with $6\phi$ tail; splices only in the middle half.
- Strong-column weak-beam: the columns at a joint should be stronger than the beams so that hinges form in the beams.

```text
   BEAM                              COLUMN
  |-2d-|--- d/2 ---|-2d-|        ---------
  |||||| | | | | | ||||||        | ##### |  s=75-100
                                 | ##### |  over lo
                                 |  # #  |  s per IS456
                                 | ##### |  s=75-100
                                 ---------
```
Members are also designed for the shear produced by plastic hinge capacity, not only by analysis, so that shear failure (brittle) cannot precede flexural yielding (ductile).

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What does the strong-column weak-beam principle aim for?
   A. Columns that yield before beams
   B. Equal strength of both
   C. Plastic hinges forming in beams rather than columns
   D. Weaker joints
   Answer: C. Hinges in beams give a controlled ductile mechanism; column hinging could cause storey collapse. (Key point: Strong-column weak-beam)

2. What is the requirement on bottom steel at a beam joint face?
   A. At least 50% of the top steel there
   B. Equal to top steel
   C. Not more than 25%
   D. None
   Answer: A. Positive steel at the joint face must be at least 50% of the negative steel to give capacity under reversal. (Key point: Beam longitudinal steel rule)

3. Why are members designed for shear from plastic hinge capacity rather than only analysis shear?
   A. To reduce stirrups
   B. So that brittle shear failure cannot occur before ductile flexural yielding
   C. Because analysis is inaccurate
   D. To increase column size
   Answer: B. Shear failure is brittle, so shear capacity is made to exceed the flexural capacity. (Key point: Design for hinge shear)

## Related in Design of RCC Structure

- [Importance of ductile detailing, sketches](https://www.bctengineer.com/question.md?key=semester_7%2Fdesign_of_rcc_structure%3Aimportance-of-ductile-detailing-sketches) — Design of RCC Structure, chapter 12
- [Ductile detailing of columns, confining steel](https://www.bctengineer.com/question.md?key=semester_7%2Fdesign_of_rcc_structure%3Aductile-detailing-of-columns-confining-steel) — Design of RCC Structure, chapter 12, asked 4×
- [Ductile design per IS 13920, beam and column](https://www.bctengineer.com/question.md?key=semester_7%2Fdesign_of_rcc_structure%3Aductile-design-per-is-13920-beam) — Design of RCC Structure, chapter 12
- [Column 350x350, 1440 kN, ductile detailing](https://www.bctengineer.com/question.md?key=semester_7%2Fdesign_of_rcc_structure%3Acolumn-350x350-1440-kn-ductile-detailing) — Design of RCC Structure, chapter 10, asked 2×
- [Short column 300x450 with ductile detailing](https://www.bctengineer.com/question.md?key=semester_7%2Fdesign_of_rcc_structure%3Ashort-column-300x450-with-ductile-detailing) — Design of RCC Structure, chapter 10
- [Beam-column joint with ductile details](https://www.bctengineer.com/question.md?key=semester_7%2Fdesign_of_rcc_structure%3Abeam-column-joint-with-ductile-details) — Design of RCC Structure, chapter 12, asked 2×

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