PAST EARTHQUAKES IN INDIA AND
THEIR RETROFITTING
TECHNIQUES
BY
Y.BOOPATHI
2004 INDIAN OCEAN EARTHQUAKE AND
TSUNAMI
 It was an undersea mega thrust earthquake that
occurred at 00:58:53 UTC on Sund...
 The earthquake was caused by subduction and triggered
a series of devastating tsunamis along the coasts of most
landmass...
 With a magnitude of Mw 9.1–9.3, it is the third largest
earthquake ever recorded on a seismograph. The
earthquake had th...
 The hypocentre of the main earthquake was
approximately 160 km (100 mi), in the Indian Ocean
just north of Simeulue isla...
TECTONIC PLATES
 An estimated 1,600 kilometres (1,000 mi) of fault
surface slipped (or ruptured) about 15 metres (50 ft)
...
 Seismographic and acoustic data indicate that the first
phase involved a rupture about 400 kilometers (250 mi)
long and ...
ENERGY RELEASED
 The energy released on the Earth's surface only
(ME, which is the seismic potential for damage) by
the 2...
DEATH TOLL AND CASUALTIES
 According to the U.S. Geological Survey a total of
227,898 people died.
 Indonesia was the wo...
RETROFITTING TECHNIQUES USED IN
MASONRY STRUCTURE
 The following failure modes characteristic of
confined masonry walls:
...
SHEAR FAILURE OF CONFINED MASONRY
WALLS
 Flexural failure caused by in-plane lateral loads is
characterized by horizontal cracking in the mortar
bed joints on th...
FLEXURAL FAILURE OF CONFINED MASONRY
WALLS
KEY FACTORS INFLUENCING SEISMIC
RESISTANCE
OF CONFINED MASONRY STRUCTURES
 Wall Density
 Masonry Units and Mortar
The la...
 Horizontal Wall Reinforcement
 to provide horizontal joint reinforcement in the form of
one or two wires laid in the mo...
 Openings
when the opening area is less than approximately
10% of the total wall area, the wall lateral load resistance
i...
SOME OF THE MASONRY STRUCTURE FAILURE
EARTHQUAKE-RESISTANT CONFINED MASONRY
CONSTRUCTION: A GUIDELINE
 Background
Confined masonry construction has typically
p...
ARCHITECTURAL GUIDELINE
BUILDING LAYOUT
BUILDING ASPECT RATIO
SYMMETRICAL WALL LAYOUT
CONTINUOUS WALLS UP THE BUILDING
HEIGHT
POSITION OF OPENINGS IN A BUILDING
MASONRY WALL CONSTRUCTION
FOUNDATION CONSTRUCTION: A) RC
PLINTH BAND AND STONE MASONRY
FOUNDATION; B) RC STRIP FOOTING
LINTEL BEAM RENFORCEMENT (TIE-COLUMN
REINFORCEMENT) EXCEED 1.5M
CONFINED MASONRY CONSTRUCTION
 Over the last 100 years, confined masonry
construction has emerged as a building technolog...
A TYPICAL CONFINED MASONRY BUILDING
CONFINED MASONRY BUILDING
 The structural components of a confined masonry
building are
Masonry walls – transmit the grav...
 Confining elements (tie-columns and tie-beams) –provide
restraint to masonry walls and protect them from
complete disint...
 Floor and roof slabs – transmit both gravity and lateral
loads to the walls. In an earthquake, slabs behave like
horizon...
Thank u
Earthquakes seminar
Earthquakes seminar
Earthquakes seminar
Earthquakes seminar
Earthquakes seminar
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Earthquakes seminar

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Earthquakes seminar

  1. 1. PAST EARTHQUAKES IN INDIA AND THEIR RETROFITTING TECHNIQUES BY Y.BOOPATHI
  2. 2. 2004 INDIAN OCEAN EARTHQUAKE AND TSUNAMI  It was an undersea mega thrust earthquake that occurred at 00:58:53 UTC on Sunday, 26 December 2004, with an epicenter off the west coast of Sumatra , Indonesia.  The resulting tsunami is given various names, including the 2004 Indian Ocean tsunami, South Asian tsunami, Indonesian tsunami, and the Boxing Day tsunami.
  3. 3.  The earthquake was caused by subduction and triggered a series of devastating tsunamis along the coasts of most landmasses bordering the Indian Ocean, killing over 230,000 people in fourteen countries, and inundating coastal communities with waves up to 30 meters (98 ft) high.[
  4. 4.  With a magnitude of Mw 9.1–9.3, it is the third largest earthquake ever recorded on a seismograph. The earthquake had the longest duration of faulting ever observed, between 8.3 and 10 minutes. It caused the entire planet to vibrate as much as 1 centimeter (0.4 inches)  In all, the worldwide community donated more than $14 billion (2004 US$) in humanitarian aid.
  5. 5.  The hypocentre of the main earthquake was approximately 160 km (100 mi), in the Indian Ocean just north of Simeulue island, off the western coast of northern Sumatra, at a depth of 30 km (19 mi) below mean sea level (initially reported as 10 km (6.2 mi))
  6. 6. TECTONIC PLATES  An estimated 1,600 kilometres (1,000 mi) of fault surface slipped (or ruptured) about 15 metres (50 ft) along the subduction zone where the India Plate slides (or subducts) under the overriding Burma Plate. The slip did not happen instantaneously but took place in two phases over a period of several minutes.
  7. 7.  Seismographic and acoustic data indicate that the first phase involved a rupture about 400 kilometers (250 mi) long and 100 kilometers (60 mi) wide, located 30 kilometers (19 mi) beneath the sea bed—the largest rupture ever known to have been caused by an earthquake  A pause of about another 100 seconds took place before the rupture continued northwards towards the Andaman and Nicobar Islands.
  8. 8. ENERGY RELEASED  The energy released on the Earth's surface only (ME, which is the seismic potential for damage) by the 2004 Indian Ocean earthquake and tsunami was estimated at 1.1×1017 joules or 26 megatons of TNT(Trinitrotoluene).  This energy is equivalent to over 1500 times that of the Hiroshima atomic bomb, but less than that of Tsar Bomba , the largest nuclear weapon ever detonated
  9. 9. DEATH TOLL AND CASUALTIES  According to the U.S. Geological Survey a total of 227,898 people died.  Indonesia was the worst affected area, with most death toll estimates at around 170,000.
  10. 10. RETROFITTING TECHNIQUES USED IN MASONRY STRUCTURE  The following failure modes characteristic of confined masonry walls: • Shear failure mode, and • Flexural failure mode  Shear failure mode is characterized by distributed diagonal cracking in the wall  A masonry wall panel resists the effects of lateral earthquake loads by itself while the confining elements (tie-columns) do not play a significant role.
  11. 11. SHEAR FAILURE OF CONFINED MASONRY WALLS
  12. 12.  Flexural failure caused by in-plane lateral loads is characterized by horizontal cracking in the mortar bed joints on the tension side of the wall  Separation of tie-columns from the wall was observed in some cases (when toothed wall-to- column connection was absent).
  13. 13. FLEXURAL FAILURE OF CONFINED MASONRY WALLS
  14. 14. KEY FACTORS INFLUENCING SEISMIC RESISTANCE OF CONFINED MASONRY STRUCTURES  Wall Density  Masonry Units and Mortar The lateral load resistance of confined masonry walls strongly depends on the strength of the masonry units and the mortar used  Tie-Columns  Tie-columns significantly influence the ductility and stability of cracked confined masonry walls.
  15. 15.  Horizontal Wall Reinforcement  to provide horizontal joint reinforcement in the form of one or two wires laid in the mortar bed joint
  16. 16.  Openings when the opening area is less than approximately 10% of the total wall area, the wall lateral load resistance is not significantly reduced as compared to a solid wall
  17. 17. SOME OF THE MASONRY STRUCTURE FAILURE
  18. 18. EARTHQUAKE-RESISTANT CONFINED MASONRY CONSTRUCTION: A GUIDELINE  Background Confined masonry construction has typically performed well in past earthquakes worldwide, when built according to code requirements. Its satisfactory earthquake performance is due to the joint action of masonry walls and their confining elements. Properly designed and built confined masonry buildings are expected to experience damage in severe earthquakes.
  19. 19. ARCHITECTURAL GUIDELINE BUILDING LAYOUT
  20. 20. BUILDING ASPECT RATIO
  21. 21. SYMMETRICAL WALL LAYOUT
  22. 22. CONTINUOUS WALLS UP THE BUILDING HEIGHT
  23. 23. POSITION OF OPENINGS IN A BUILDING
  24. 24. MASONRY WALL CONSTRUCTION
  25. 25. FOUNDATION CONSTRUCTION: A) RC PLINTH BAND AND STONE MASONRY FOUNDATION; B) RC STRIP FOOTING
  26. 26. LINTEL BEAM RENFORCEMENT (TIE-COLUMN REINFORCEMENT) EXCEED 1.5M
  27. 27. CONFINED MASONRY CONSTRUCTION  Over the last 100 years, confined masonry construction has emerged as a building technology that offers an alternative to both unreinforced masonry and RC frame construction  Confined masonry construction consists of masonry walls (made either of clay brick or concrete block units) and horizontal and vertical RC confining members built on all four sides of a masonry wall panel. Vertical members, called tie-columns orpractical columns.
  28. 28. A TYPICAL CONFINED MASONRY BUILDING
  29. 29. CONFINED MASONRY BUILDING  The structural components of a confined masonry building are Masonry walls – transmit the gravity load from the slab(s) above down to the foundation. The walls act as bracing panels, which resist horizontal earthquake forces. The walls must be confined by concrete tiebeams and tie-columns to ensure satisfactory earthquake performance.
  30. 30.  Confining elements (tie-columns and tie-beams) –provide restraint to masonry walls and protect them from complete disintegration even in major earthquakes. These elements resist gravity loads and have important role in ensuring vertical stability of a building in an earthquake.
  31. 31.  Floor and roof slabs – transmit both gravity and lateral loads to the walls. In an earthquake, slabs behave like horizontal beams and are called diaphragms.  Plinth band – transmits the load from the walls down to the foundation. It also protects the ground floor walls from excessive settlement in soft soil conditions.  Foundation – transmits the loads from the structure to the ground.
  32. 32. Thank u
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