Limit State Design Of Steel Structures By Sk Duggal Pdf (2026)

If you are preparing for competitive exams like GATE Civil Engineering, IES/ESE, or university semester exams, this book offers distinct advantages:

Arjun’s first design uses the old Working Stress Method (WSM) — high factor of safety, low material stress. His steel beam sections are heavy, expensive. Factory owner yells: “Too much steel! Waste of money!”

Arjun thinks: “Let me reduce the beam size. Nothing bad will happen.” limit state design of steel structures by sk duggal pdf

Old Man Ravi stops him: “You’re designing for a perfect world. WSM assumes steel never yields, wind never gusts, crane never jerks. But reality has limits.”

He opens Duggal’s book to Chapter 1: Limit State Philosophy. If you are preparing for competitive exams like

Prof. S.K. Duggal is a revered academician who served at the Motilal Nehru National Institute of Technology (MNNIT), Allahabad. With decades of teaching and research experience, he recognized the void in educational resources when India adopted the new code IS 800:2007 (replacing the 1984 version). His writing style is characterized by:

Problem: Design a simply supported I‑beam spanning 6 m, subjected to a uniformly distributed load of 20 kN/m and a point load of 30 kN at mid‑span. Steel grade: Fe 500 (fy = 250 MPa). Arjun’s first design uses the old Working Stress

| Step | Calculation | Result | |------|-------------|--------| | 1. Factored load | ( w_d = 1.5 \times 20 = 30 \text kN/m ) ( P_d = 1.5 \times 30 = 45 \text kN ) | — | | 2. Maximum moment | ( M_d = \fracw_d L^28 + \fracP_d L4 = \frac30 \times 6^28 + \frac45 \times 64 = 135 + 67.5 = 202.5 \text kN·m ) | — | | 3. Choose section | IS 2062 I‑250 (Ag= 12 900 mm², Iz= 2.5 × 10⁶ mm⁴) | — | | 4. Plastic moment | ( M_p = 0.66 f_y A_g Z = 0.66 \times 250 \times 12 900 \times 0.9 \approx 1 920 \text kN·m ) | (compact) | | 5. Design strength | ( \phi M_n = 0.9 \times M_p = 1 728 \text kN·m ) | — | | 6. ULS check | ( M_d = 202.5 \text kN·m \le 1 728 \text kN·m ) | OK | | 7. Deflection (SLS) | ( \Delta = \frac5 w L^4384 E I = \frac5 \times 20 \times 6^4384 \times 200 000 \times 2.5 × 10^6 \approx 7.5 \text mm ) | Limit L/250 = 24 mm → OK |

The example demonstrates the seamless flow from load factoring to final verification, mirroring the methodology in Duggal’s PDF.