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Retrofitting of Masonry Buildings

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Manish Sharma
Manish Sharma

This document discusses retrofitting techniques for masonry buildings to strengthen them against earthquakes. It describes various structural and member retrofitting methods such as adding shear walls, jacketing beams and columns. Failure mechanisms of masonry buildings are outlined, including out-of-plane failure, in-plane failure and connection failure. Repair techniques like jacketing are explained. The document also references Indian codes for earthquake design and concludes that retrofitting is an effective technology for protecting structures, but expertise is still needed at the basic level.

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Retrofitting of Masonry Buildings Submitted by- MANISH SHARMA Submitted to- Dr. AKILAHMAD
Retrofitting- It is a technique for upgrade the strength and structural capacity of an existing/damaged structure to enable it to safely withstand the effect of strong earthquake in future.
Retrofitting techniques:- Structural or global retrofitting 1. Adding shear wall 2. Adding infill wall 3. Adding bracing 4. Adding wing wall/ buttresses 5. Wall thickening 6. Mass reduction 7. Supplemental damping and Base isolation Member or local retrofitting 1. Jacketing of beams 2. Jacketing of columns 3. Jacketing of beam column joints 4. Strengthening individual footings
Failure mechanism of a masonry building:- Out-of- plane failure In-plane failure Connection failure Diaphragm failure Pounding Failure due to opening in the walls Non-structural component failure
Out-of- plane failure:- Inadequate anchorage of wall into the roof diaphragm. Limited tensile strength of masonry. More pronounced response at higher levels.
Retrofitting of Masonry Buildings
In-plane failure:- In plane failures of walls in un-reinforced masonry structure are due to excessive bending or shear. Commonly it leads to form double diagonal shear cracking.
Connection failure:- This type of failure is characterized by diagonal cracks disposed on both the walls edge causing separation and collapse of the corner zone.
Diaphragm failure:- Diaphragm failure is a rare phenomenon in the event of seismic motion. In plane rotation of the diaphragm ends and absence of good shear transfer between diaphragm and reaction walls account for damages at corner of the walls.
Pounding:- When adjacent roof levels of the two buildings and vertical brick walls faces flush with one another ,the pounding action causes structural distress due to out-of-plane vibrations.
Non-structural component failure:- Parapet walls, partition walls, mumty, water tanks, projections and staircase are non structural elements behave like cantilevers if they remain unrestrained and are subjected to greater amplification as compared to ground motion becoming prone to failure.
MASONRY CRACKING:- GRADE CRACKS DAMAGE LEVEL DEFINATION FOR LOAD BEARING MASONRY G0 Undamaged No visible damage G1 Slight damage Hairline cracks G2 Moderate damage Cracks 5-20 mm G3 Heavy damage Cracks 20 mm or wall material dislodge G4 Partial destruction Complete collapse of individual wall material or roof support G5 Collapse More than one wall collapsed or more than half of roof
REPAIRING TECHNIQUES OF MASONARY:-
Retrofitting of Masonry Buildings
Retrofitting of Masonry Buildings
Retrofitting of Masonry Buildings
Retrofitting of Masonry Buildings
Retrofitting of Masonry Buildings
Jacketing:-- Most popular method for strengthening of buildings columns. Types:-- 1.Steel jacket 2.Reinforced concrete jacket 3.Reinforced polymer composite (RPC) jacket Purpose of Jacketing:- To increase shear strength. To increase flexural strength To increase concrete coinforment
Retrofitting of Masonry Buildings
Indian Codes for Earthquake Design:- IS: 1893-2002 (part-1) Criteria for Earthquake Resistant Design of Structures (Part 1 :General Provision and Buildings) - Code of Practice. Practice IS: 4326-1993 Earthquake Resistant Design and Construction of Buildings Code of practice. IS: 13920-1993 Ductile Detailing of Reinforced Concrete Structures subjected to Seismic Forces Code of Practice IS: 13935-1993 Repair and Seismic Strengthening of Buildings Guidelines IS: 13828-1993 Improving Earthquake Resistance of LowStrength Masonary Buildings - Guidelines IS: 13827-1993 Improving Earthquake Resistance of Earthen Buildings Guidelines
Shaking table test:-
Conclusions:- Seismic Retrofitting is a suitable technology for protection of a variety of structure. it has matured in the recent years to a highly reliable technology. But, the expertise needed is not available in basic level. The main challenge is to achieve a desired performance level at a min cost. Which can be acheived through a detailed nonlinear analysis. Optimization techniques are needed to known the most efficient retrofit for a particular structure. Proper design codes are needed to be published as code of practice for professionals related to this field.
REFERENCES:- Agarwal, P. and Shrikhande, M., 2006, Earthquake Resistant Design of Structures, 2nd Edition, Prentice-Hall of India Private Limited, New Delhi. Fastening for seismic retrofitting- state of art report, comite euro. International Du Beton,Thomas Telford,UK,1995. EERI, 1999, Lessons Learnt Over Time Learning from Earthquakes Series: Volume II Innovative Recovery in India, Earthquake Engineering Research Institute, Oakland (CA), USA. Murthy,C.V.R.,2004 IITK-BMTPC Earthquake Tip, New Delhi.
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Retrofitting of Masonry Buildings

  • 1. Retrofitting of Masonry Buildings Submitted by- MANISH SHARMA Submitted to- Dr. AKILAHMAD
  • 2. Retrofitting- It is a technique for upgrade the strength and structural capacity of an existing/damaged structure to enable it to safely withstand the effect of strong earthquake in future.
  • 3. Retrofitting techniques:- Structural or global retrofitting 1. Adding shear wall 2. Adding infill wall 3. Adding bracing 4. Adding wing wall/ buttresses 5. Wall thickening 6. Mass reduction 7. Supplemental damping and Base isolation Member or local retrofitting 1. Jacketing of beams 2. Jacketing of columns 3. Jacketing of beam column joints 4. Strengthening individual footings
  • 4. Failure mechanism of a masonry building:- Out-of- plane failure In-plane failure Connection failure Diaphragm failure Pounding Failure due to opening in the walls Non-structural component failure
  • 5. Out-of- plane failure:- Inadequate anchorage of wall into the roof diaphragm. Limited tensile strength of masonry. More pronounced response at higher levels.
  • 7. In-plane failure:- In plane failures of walls in un-reinforced masonry structure are due to excessive bending or shear. Commonly it leads to form double diagonal shear cracking.
  • 8. Connection failure:- This type of failure is characterized by diagonal cracks disposed on both the walls edge causing separation and collapse of the corner zone.
  • 9. Diaphragm failure:- Diaphragm failure is a rare phenomenon in the event of seismic motion. In plane rotation of the diaphragm ends and absence of good shear transfer between diaphragm and reaction walls account for damages at corner of the walls.
  • 10. Pounding:- When adjacent roof levels of the two buildings and vertical brick walls faces flush with one another ,the pounding action causes structural distress due to out-of-plane vibrations.
  • 11. Non-structural component failure:- Parapet walls, partition walls, mumty, water tanks, projections and staircase are non structural elements behave like cantilevers if they remain unrestrained and are subjected to greater amplification as compared to ground motion becoming prone to failure.
  • 12. MASONRY CRACKING:- GRADE CRACKS DAMAGE LEVEL DEFINATION FOR LOAD BEARING MASONRY G0 Undamaged No visible damage G1 Slight damage Hairline cracks G2 Moderate damage Cracks 5-20 mm G3 Heavy damage Cracks 20 mm or wall material dislodge G4 Partial destruction Complete collapse of individual wall material or roof support G5 Collapse More than one wall collapsed or more than half of roof
  • 19. Jacketing:-- Most popular method for strengthening of buildings columns. Types:-- 1.Steel jacket 2.Reinforced concrete jacket 3.Reinforced polymer composite (RPC) jacket Purpose of Jacketing:- To increase shear strength. To increase flexural strength To increase concrete coinforment
  • 21. Indian Codes for Earthquake Design:- IS: 1893-2002 (part-1) Criteria for Earthquake Resistant Design of Structures (Part 1 :General Provision and Buildings) - Code of Practice. Practice IS: 4326-1993 Earthquake Resistant Design and Construction of Buildings Code of practice. IS: 13920-1993 Ductile Detailing of Reinforced Concrete Structures subjected to Seismic Forces Code of Practice IS: 13935-1993 Repair and Seismic Strengthening of Buildings Guidelines IS: 13828-1993 Improving Earthquake Resistance of LowStrength Masonary Buildings - Guidelines IS: 13827-1993 Improving Earthquake Resistance of Earthen Buildings Guidelines
  • 23. Conclusions:- Seismic Retrofitting is a suitable technology for protection of a variety of structure. it has matured in the recent years to a highly reliable technology. But, the expertise needed is not available in basic level. The main challenge is to achieve a desired performance level at a min cost. Which can be acheived through a detailed nonlinear analysis. Optimization techniques are needed to known the most efficient retrofit for a particular structure. Proper design codes are needed to be published as code of practice for professionals related to this field.
  • 24. REFERENCES:- Agarwal, P. and Shrikhande, M., 2006, Earthquake Resistant Design of Structures, 2nd Edition, Prentice-Hall of India Private Limited, New Delhi. Fastening for seismic retrofitting- state of art report, comite euro. International Du Beton,Thomas Telford,UK,1995. EERI, 1999, Lessons Learnt Over Time Learning from Earthquakes Series: Volume II Innovative Recovery in India, Earthquake Engineering Research Institute, Oakland (CA), USA. Murthy,C.V.R.,2004 IITK-BMTPC Earthquake Tip, New Delhi.