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Basics of earthquake & structural and non structural guidelines for building construction in eq prone areas

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The presentation covers the scenario post a hazard of Earthquake turned into a disaster. Further, it includes the basic terminology, dynamics of EQ event, and suggests remedial practices for structural and non-structural elements of a building. Purpose the compilation is to sensitize learners.

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Basics of earthquake & structural and non structural guidelines for building construction in eq prone areas

  1. 1. An academic purpose compilation by Prof. Bhasker V. Bhatt PG In-charge (ME TCP) & Assistant Professor in Civil Engineering Department, SCET, Surat
  2. 2. Earthquake
  3. 3. What is an Earthquake? A Vibrations produced in the earth’s crust when rock’s elastic strain has ruptured and rebounded
  4. 4. What causes an earthquake? Earthquakes are usually caused by sudden movement on faults
  5. 5. What causes an earthquake? A sudden release of energy accumulated in deformed rocks causing the ground to tremble or shake. Causes rupturing or brittle failure of crustal rocks. Energy is released. Movement of fault blocks takes place along a fault plane.
  6. 6. After energy is released, friction between the adjacent fault blocks prevents further movement. Stress resumes and builds up again. Friction between the blocks is overcome. Another earthquake occurs.
  7. 7. Gujarat Earthquake Concrete Building
  8. 8. Mexico Earthquake Apartment Building
  9. 9. Soft-story Collapse
  10. 10. Gujarat EQ
  11. 11. Mexico Earthquake School Building
  12. 12. Gujarat EQ Large blocks piled up using weak bond
  13. 13. Gujarat EQ Many casualties occurred in stone masonry buildings
  14. 14. Gujarat EQ Strong Structure – Weak Joint with masonry
  15. 15. Gujarat EQ Soft story
  16. 16. Liquefaction Nigata, Japan
  17. 17. Our Earth is Alive
  18. 18. Plate Tectonics
  19. 19. What is Mechanism of Earthquake ?
  20. 20. Different Plates around the World
  21. 21. Earthquake Occurrence
  22. 22. Himalayan Mountains
  23. 23. Earthquake
  24. 24. Seismic Waves
  25. 25. Measuring Earthquakes
  26. 26. Site Effect The shape, amplitude, and the duration of a seismic movement are affected, among other things, by its magnitude, the distance to the hypocenter, and the local site conditions
  27. 27. Buildings Configuration Problem
  28. 28. Irregular Shape
  29. 29. Torsion
  30. 30. Overturning Building Seldom Overturn- They fall apart or pancake
  31. 31. Soft-story Collapse Mechanism
  32. 32. Ductility
  33. 33. Lateral Force Resisting Systems
  34. 34. Architectural consideration in Building Layout and Configuration
  35. 35. Building Configuration 2 3 2 1 1 3 Symmetrical buildings in plan and elevation are better than asymmetrical ones.
  36. 36. Irregularity and Seismic Joints
  37. 37. Asymmetry (false symmetry) due to the location of structural elements
  38. 38. Unsuitable plan Suitable plan In order to make unsuitable building plans seismically acceptable, they need to be divided into a number of rectangular or symmetrical units. Building Configuration Pounding Effect
  39. 39. Building Configuration contd.... The same principle can be applied to the elevations of the buildings
  40. 40. b h h b Height of the building should be less than 3b Building Configuration contd....
  41. 41. Ideal Earthquake Resistant Building  Small mass  Low Height-to-base ratio  Low center of mass relative to the ground  Balanced lateral resistance  Direct load paths  Symmetrical Plan  Uniform section and elevation  Uniform floor heights, and  Maximum rotational resistance  Short spans
  42. 42. Building Configuration Do and Don’t do
  43. 43. Abrupt stiffness change in elevation due to infills Increase of Ground Floor stiffness and strength or
  44. 44. Asymmetry of building in Plan Seismic Joints Or Strengthening of Connection
  45. 45. Abrupt Stiffness change in building in Plan Seismic Joints
  46. 46. No Yes Interaction of Structural Elements of Different Stiffness Seismic Joint Proper Design OR Strengthening of Flexible Element
  47. 47. Significant difference between stiffness in x and y Balanced stiffness in x and y Asymmetric arrangement of Vertical element (Torsional Vibration) symmetric arrangement of Vertical element No Yes
  48. 48. Small contribution of Shear wall in Torsional resistance Increase of Torsional resistance Incorrectly supported columns Uniform Column No Yes
  49. 49. Unclear Frame Behavior Good Frame Behavior in x and y Strong beam-weak Column (column Failure mechanism) Weak (comparatively) beam-strong Column (Beam Failure mechanism) No Yes
  50. 50. Stitch at L-junctions and T-junctions should be designed to mitigate the problem Masonry Buildings
  51. 51. Masonry Buildings contd.…. Horizontal band at sill, lintel and eve level should be designed for out of plane bending
  52. 52. Masonry Buildings contd.…. Stitch and band give more integrity to the building elements and protect the building from corner opening and out of plane failure
  53. 53. Masonry Buildings contd.…. Vertical bars at corners T-joints and around the openings should be designed for tensile stress developed
  54. 54. RC Buildings Brittle failure of RC building
  55. 55. RC Buildings contd….. Failure of building at beam column joints Joint Reinforcing Unreinforced beam-column joints may not be able to develop the strength of the connected members, and this can lead to sudden brittle failure of the joint
  56. 56. Damage at Joint and Column
  57. 57. RC Buildings contd….. What is our practice?
  58. 58. RC Buildings contd….. Joint Reinforcing...
  59. 59. RC Buildings contd….. Failure at cold Joint
  60. 60. RC Buildings contd….. What we are constructing? Cold joint...
  61. 61. RC Buildings contd….. Cold joint... Shear key and rough surface give better performance
  62. 62. RC Buildings contd….. Column tie spacing and tie hooks Can only longitudinal bars save the column?
  63. 63. RC Buildings contd….. Column tie spacing and tie hooks…. Comparison of damage of two columns
  64. 64. RC Buildings contd….. Column tie spacing and tie hooks….
  65. 65. RC Buildings contd….. Short column effect…...
  66. 66. Short column effect…... RC Buildings contd…..
  67. 67. Short column effect…... RC Buildings contd…..
  68. 68. RC Buildings contd….. Column-bar splices
  69. 69. Non structural Damage and its Mitigation
  70. 70. Broken Glass in Kitchen
  71. 71. Room In Bed Rooms Furniture overturned throwing outside the contents
  72. 72. Bureau Toppled
  73. 73. Office In office Furniture, file cabinets overturned
  74. 74. Shops In shops and departmental stores Many liquor and bottles broken
  75. 75. Non-structural damage In Book Store and Libraries
  76. 76. Non-structural damage Shattered glasses
  77. 77. Water Heaters Tip Easily During Earthquakes
  78. 78. Significance: Life Safety  If a ten-rupees flowerpot , not fastened well to the building, falls on someone’s head, it can be a killer!
  79. 79. Significance: Property Loss  Very important in case of commercial and Institutional buildings  Property losses in 25 commercial buildings due to the 1971 San Fernando earthquake:  Structural damage 3%  Electrical and mechanical 7%  Exterior finishes 34%  interior finishes 56%.
  80. 80. Significance: Loss of function  Critical facility  Hospital  Telecommunication etc.
  81. 81. Mitigation Measures : Removal  A hazardous material that could be spilled, could be stored perfectly well outside the premises  One solution would be stronger fastening or the use of stronger supports,  But the most effective solution would be removal and replacement
  82. 82.  A very heavy object on top of a shelf could fall and seriously injure someone  If it is relocated to a floor-level shelf it would not represent any danger to human lives or to property. Store large, heavy or fragile objects on lower shelves or in low closed cabinets Relocation
  83. 83.  Anchorage of Battery Rack+ Anchorage of Book shelve SOURCE: EERI Anchorage
  84. 84. Anchorage SOURCE: PAHO/WHO
  85. 85. Restricted Mobilization  It does not matter if the cylinders shift as long as they do not fall and break their valves. Sometimes back-up power generators are mounted on springs to reduce the noise and vibrations when they are working, but these springs would amplify ground motion.
  86. 86. Flexible Couplings The use of flexible piping in critical areas such as between buildings and equipment helps to prevent breakage PAHO/WHO
  87. 87. Supports Damage to ceilings
  88. 88. Supports
  89. 89. Substitution  A heavy tiled roof does not only make the roof of a building heavy, it is also more susceptible to earthquake shaking. The individual tiles tend to come off, creating a hazard for people and for objects.  One solution would be to change it for a lighter, safer roofing material.
  90. 90. Modification  Rolls of transparent adhesive plastic may be used to cover the inside surfaces and prevent them from shattering and threatening those inside.
  91. 91. Reinforcement  Useful for  Unreinforced infill wall  Chimney may be strengthened
  92. 92. Redundancy  Redundancy or duplication of items is advisable.  An emergency response plan requiring storage of emergency supplies is a good idea.  It is possible/necessary to store extra quantities of certain products, providing a certain level of independence from external supply which could be interrupted in the case of earthquakes.
  93. 93. Limit Sliding & Rocking Movements
  94. 94. Restraints and fasteners for smaller equipment
  95. 95. Simple improvement can save life and property
  96. 96. Nonstructural Vulnerability Reduction
  97. 97. BHASKER BHATT Consulting Town Planner and Civil Engineer C:+91-98258-35364 E: er.bhasker@gmail.com Promote & Practice Safe Construction…  Thanks…

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