--- title: "Design process for masonry wall under lateral loads" subject: "Concrete Technology and Masonry Structure" chapter: 9 key: "semester_5/concrete_technology_and_masonry_structure:design-wall-lateral-loading" source: https://www.bctengineer.com/q/semester_5/concrete_technology_and_masonry_structure/design-wall-lateral-loading site: BCT Engineering --- # Design process for masonry wall under lateral loads Concrete Technology and Masonry Structure · Chapter 9: Masonry structures under lateral loads - Asked in: 2072 Kartik, 8 marks - Video: [Design of hollow Masonry wall Session 4](https://www.youtube.com/watch?v=gmoGbg_9vjM) — Dr. Ratna Tej Reddy K - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_5/concrete_technology_and_masonry_structure/design-wall-lateral-loading - Whole chapter: https://www.bctengineer.com/md/semester_5/concrete_technology_and_masonry_structure/chapter-9 ## Question Explain the design process for a masonry wall under lateral loadings. ## Short answer Determine lateral load and support condition, compute bending moment (e.g., wH²/2 cantilever, wH²/8 simply supported). Add vertical load to find eccentricity e=M/N, check stresses (no tension or limited to 0.07 N/mm² vertically, 0.14 horizontally), perform compression check with 25% increase if e/t>1/24, and detail anchors. ## Answer A masonry wall under lateral load (wind, earthquake or earth pressure) is designed by the working-stress method as per IS 1905 cl. 5.5.2 and 5.5.3. #### Design steps 1. **Establish the lateral load:** wind pressure from IS 875 (Part 3) (as the design wind pressure $p_z$) or the seismic force; load per metre run $w$. 2. **Support conditions:** identify the structural system: cantilever (free-standing), simply supported between floor and roof (anchored), propped cantilever (fixed base, tied top), or panel supported on 3 or 4 edges (App. D). 3. **Bending moment:** cantilever $M=wH^2/2$; simply supported $M=wH^2/8$; fixed both ends $M=wH^2/12$; propped cantilever $M=wH^2/8$ at the fixed end. 4. **Vertical load:** add the vertical loads and self weight at the critical section. 5. **Effective height, slenderness ratio** (Tables 4, 5, 7) and **eccentricity** $e=M/N$ (or the load eccentricity). 6. **Stresses:** $\sigma = N/A \pm 6M/t^2$ per metre; check for no tension, or tension limited to 0.07 N/mm$^2$ for vertical bending (tension perpendicular to the bed joints) and 0.14 N/mm$^2$ for horizontal bending (tension parallel to the bed joints), with M1 mortar or richer (cl. 5.4.2). 7. **Compression check:** $\sigma \le f_b k_s k_a k_p$, with a 25 percent increase if $1/24|w ->|w | | | ===== anchor ===== M=wH^2/2 M=wH^2/8 M=wH^2/8 (base) ``` ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What is the moment for a free-standing cantilever wall? A. M = wH^2/2 B. wH^2/8 C. wH^2/12 D. wH Answer: A. Cantilever formula. (Key point: Cantilever moment) 2. How are stresses checked? A. sigma = N x M B. sigma = N/A +/- 6M/t^2 per metre, limited tension 0.07 N/mm^2 C. Tension unlimited D. Only shear Answer: B. Vertical bending tension limit with M1 mortar. (Key point: Stresses) 3. What is required for a free-standing wall? A. Equal to overturning B. 0.5 times C. Stability moment at least 1.5 times overturning moment D. No check Answer: C. Factor of safety 1.5. (Key point: Free-standing stability) 4. When is the 25 percent increase allowed? A. e/t > 1/6 B. e = 0 C. e/t < 1/24 D. When 1/24 < e/t <= 1/6 Answer: D. IS 1905 cl. 5.4.1.4. 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