Lec 25: Deep Beam Design: Example

Lec 25: Deep Beam Design: Example

by Prof. Arunasis Chakraborty

Applied Sciences & Engineering Engineering & Technology TNCivil engineering, surveying and buildingTNKBuilding construction and materials
🎙 Prof. Arunasis Chakraborty 👥 226K 📅 February 27, 2026 ⏱ 10 min 👁 1K 📄 tutorial 🧭 2026-08-02
Available in: English (current) Français

Keywords

deep beamdesign examplereinforced concretelever armsteel reinforcement

Summary

This lecture, part of the NPTEL course on Reinforced Concrete Design, presents a complete design example of a simply supported deep beam. The instructor begins by recapping the key design steps for deep beams, including the definition based on effective span-to-depth ratio, the non-linear strain profile, and the empirical formulas for the lever arm (z) from the code. He then applies these steps to a specific problem: a simply supported beam with M30 concrete, Fe415 steel, width 250 mm, overall depth 3.75 m, clear span 6 m, and a live load of 215 kN/m. The effective span is calculated as 6.3 m, giving a span-to-depth ratio of 1.68, confirming it as a deep beam. The total load and bending moment are computed, and the lever arm is found using the code formula, leading to an area of steel of 1187.1 mm². The main reinforcement is provided as six 16 mm bars in two layers. Additionally, vertical and horizontal reinforcement are detailed as per code requirements (0.12% and 0.2% of gross area respectively), using 8 mm bars at 250 mm spacing. The detailing is illustrated, and the instructor notes that the moment used was unfactored, so for factored loads the steel area should be increased by 1.5, resulting in nine 16 mm bars. The lecture concludes with a summary of the design process.

222 words

Critical Evaluation

The lecture provides a clear and systematic walkthrough of a deep beam design example, which is valuable for students and practitioners. The instructor correctly emphasizes the key differences between deep and shallow beams, such as the non-linear strain distribution and the use of empirical lever arm expressions. The calculations are presented step-by-step, making it easy to follow. However, the lecture lacks a critical discussion of the underlying assumptions and limitations of the code provisions. For instance, the empirical formulas for the lever arm are based on experimental data and may not be applicable to all cases, but this is not mentioned. The instructor also does not reference specific IS 456 clauses, which would help viewers verify the provisions. The example is simplified, as it does not consider factors like shear, deflection, or crack control, which are crucial in deep beam design. The presentation is clear, but the audio quality and visual aids are basic. The adéquation between title and content is perfect. Overall, the lecture is a good educational resource, but it could be enhanced by including more context and critical analysis.

182 words

Title / Content Match

The title accurately reflects the content: a step-by-step design example of a deep beam.

Quality & Reliability

8/10

The lecture is part of a formal NPTEL course by IIT Guwahati, providing a worked example of deep beam design following standard code provisions (IS 456). The methodology is clearly explained, and the calculations are transparent. The content is reliable for educational purposes, though it lacks references to specific code clauses and does not discuss limitations or alternative methods.

Key Moments

Markers derived by PSI from the transcript: the creator did not define chapters.

Cited Sources

Concurring Sources

Contribution & Novelties

This lecture provides a practical, step-by-step example of deep beam design, which is a specialized topic in reinforced concrete design. It demonstrates the application of code-based empirical formulas for lever arm and reinforcement detailing, which is valuable for engineering students and professionals. The example clarifies the design process for simply supported deep beams, including the calculation of effective span, bending moment, and steel requirements.

Pour aller plus loin :

116 words

Radar Profile

The radar profile shows high scores in quality of information, technical level, and reliability, indicating a technically sound and well-structured lecture. The quantity of information is slightly lower, as the lecture focuses on a single example rather than covering broader concepts.

Reliability 8/10