The document discusses experimental tests conducted on full-scale masonry walls to evaluate stress reduction factors under axial and eccentric loading. Tests were conducted on bricks, mortar, masonry prisms and two axially loaded walls and two eccentrically loaded walls. Stress reduction factors were computed using a secant formula and compared to code provisions. The stress reduction factor obtained from experiments was 0.40, which compared reasonably well with Eurocode and British code provisions but not with the Indian code.

1. EVALUATION OF STRESS REDUCTION FACTORS BASED ON TESTS ON AXIALLY AND ECCENTRICALLY LOADED WALLS KRISHNA KUMAR S 1BM08CCT07 GUIDED BY Smt MANGALA KESHAVA Assistant Professor, Dept of Civil Engineering, BMSCE B’lore BY

8. GREAT WALL OF CHINA

13. Cavity wall Solid wall Panel wall

17. Literature Review

18. Compressive strength of bricks ***Gumaste(2004 )

22. Details of tests carried on full scale walls

24. Design of Masonry Wall for Vertical Load (IS 1905) Factors: Slenderness Ratio Stress reduction factors Effective length Effective thickness Effective height Eccentricity of load Thickness of wall Eccentricity ratio

25. Masonry Walls: Slenderness and Eccentricity Stocky wall, central load Slender wall, central load 100% strength Reduced strength

26. Masonry Walls: Slenderness and Eccentricity Stocky wall, eccentric load Slender wall, eccentric load Reduced strength Reduced strength e e

27. Effect of slenderness and eccentricity

28. Masonry Walls: Slenderness and Eccentricity IS 1905 1987 Slenderness Ratio = Effective Height/Effective Thickness (or) = Effective Length/Effective Thickness *** whichever is least

29. Masonry Walls: Slenderness and Eccentricity IS 1905 - 1987 Effective Height = Actual Height * a number from 0.75 to 1.5, depending on the end fixity ***In the present study depending on boundary condition provided it was considered 0.85 H as per IS 1905 - 1987

30. Masonry Walls: Slenderness and Eccentricity IS 1905 – 1987 Effective Length = Actual Length * a number from 0.80 to 2.0 depending on the end fixity

33. VAULT PITHCED ROOF

35. Tests on Bricks

36. Avg. Dry density C.O.V Range 1.75 g/cc 1.70% 1.6-1.95g/cc ****

37. Water Absorption(%) (Avg) C.O.V Range 13.90 2.06% ≤ 20%**

38. ***Sarangpani 1998 I.R.A kg/m 2/ min C.O.V Range kg/m 2/ min 2.815 8.55% 1.35-3.53**

39. ***Sarangpani1998, Raghunath 2003 for T.M.B of Bangalore Compressive Strength = Ultimate Load MPa. Area of Loading Compr . Strength (MPa) C.O.V Range (MPa) 5.32 2.56% 3-11***

40. E = 752.6 MPa from the Graph

43. Mortar cone before and after applying jolts Conical mould Rigid frame Brass plate-circular

45. 225 mm masonry prism and stack bonded prism before testing

46. Stress strain curve for prisms

51. 4 legged loading frame-reaction type Courtesy-RVCE

53. 1.55m 0.95m 0.225m

54. Arrangement for Ecc.loading 0.5m 1.3m 1.0m DIAL GAUGE POSITION

55. Plan of Eccentric loading arrangement-1 Plan of Eccentric loading arrangement-2

56. Test Set-up details

57. WALL1- Front face and Rear face after testing Crushing of brick vertical splitting

58. WALL2- Front face and Rear face after testing Spalling Vertical cracks

60. Eccentric loading before and after failure

61. CRACK PATTERN-ECCENTRICALLY LOADED Separation of 2 leaves of wall

63. Wall1

64. Wall2

65. Wall3

66. wall4 WALL 4(ECC2)

67. SUMMARY OF WALL TESTED

70. Where σ max from experiment on walls ‘ E’ VALUE from prism experiment (e/t)= eccentricity ratio (l/t)= slenderness ratio

72. (P/A) values

73. Stress reduction factor obtained

76. Graph showing stress reduction factors for varying eccentricites and slenderness ratio as per Euro-code (ENV 1996-1-1-1995) 0.48

83. THANK YOU THANK YOU