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Presented by Muhammad Rizwan Riaz

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  1. 1. RETROFITTING(Seismic Design of Structures)Presented by:Muhammad Rizwan Riaz (2011-MS-CES-01)
  2. 2. CONTENTSThe discussion is divided into the following sections :• Introduction• Retrofitting Techniques• Economic features of various Retrofitting Techniques• Need of Retrofitting in Pakistan• New trends of Retrofitting in Pakistan
  3. 3. Retrofitting• Upgrading of certain building systems (existing structures) to make them more resistant to seismic activity (earthquake resistance)• Structures can be – Earthquake damaged – Earthquake vulnerable Retrofitting proves to be a better economic consideration and immediate shelter to problems rather than replacement of building.
  4. 4. Retrofitting Techniques
  5. 5. Classification of Retrofitting1. Retrofitting of reinforced concrete (RC) structures2. Retrofitting of masonry structuresRETROFITTING OF RC STRUCTURESa) Strengthening Existing Members• Reinforced Concrete Jacketing• Steel Plate Bonding and Jacketing, Steel section caging; FRP• Plate Bonding and Jacketing
  6. 6. Reinforced Concrete Jacketing
  7. 7. Reinforced Concrete Jacketing
  8. 8. Column with CFRP Wrap
  9. 9. Column with Steel Jacketing
  10. 10. Column with Steel Caging
  11. 11. Retrofitting Of RC Structuresb) Adding New members• Shear walls• Frames (moment resisting frames and braced frames)• Bracings• Buttresses
  12. 12. Shear Wall in Soft Story
  13. 13. Frames and shear wall
  14. 14. Steel Bracing in Soft Story
  15. 15. Steel Bracing
  16. 16. Introducing Buttresses
  17. 17. Retrofitting Of Masonary StructuresPRINCIPLE OF SEISMIC SAFETY OF MASONRY BUILDINGS• Integral box action• Integrity of various components – Roof to wall – Wall to wall at corners – Wall to foundation• Limit on openings
  18. 18. Retrofitting Of Masonary StructuresMETHODS FOR RETROFITTING OF MASONRY BUILDINGSREPAIRING (IMPROVING EXISTING MASONRY STRENGTH)• Stitching of cracks• Grouting with cement or epoxy• Use of CFRP (carbon fiber reinforced polymer) strips
  19. 19. Stitching of cracks in masonry walls
  20. 20. Repair of damaged member
  21. 21. Retrofitting Of Masonary StructuresRETROFITTING OF EQ. VULNERABLE BUILDINGS:• External binding or jacketing• Shotcreting• Strengthening of wall intersections• Strengthening by cross wall• Strengthening by buttresses• Strengthening of arches
  22. 22. Integral box action
  23. 23. Strengthening of wall intersections
  24. 24. Strengthening by cross wall
  25. 25. Strengthening by Buttresses
  26. 26. Strengthening of Arches
  27. 27. Economic Features of Various Retrofitting Techniques
  28. 28. Economic Features of Various Retrofitting Techniques
  29. 29. Need of Retrofitting in PakistanThere are considerable number of reinforced concretestructures in Pakistan that do not meet the requirementsof current design standards because of inadequate designand/or construction errors and need structural upgradingspecially to meet the seismic design requirements.After 2005 earthquake, the awareness and need ofseismic detailing has increased.Retrofitting is the best solution to strengthen suchbuildings without replacing them
  30. 30. New Trends in Retrofitting in PakistanStrengthening Techniques• Reinforcement Strengthening• R.C Jacketing• Externally Bonded Plates For Flexural Strengthening• Shear/Compression Strengthening by ConfinementCarbon Fiber Reinforced Polymer (CFRP) Composite System
  31. 31. New Trends in RetrofittingSIKA Construction Chemicals Division, Imporient Chemicals (PVT) Ltd. is widely involved in the use of these materials for retrofitting in Pakistan.The retrofitting done by SIKA, involves the following materials• CFRP Strips (Sika CarboDur)• Structural Epoxy Adhesive (SikaDur-30)• Glass and carbon Fabric (Sika Wrap)
  32. 32. CFRP Plate Systems
  33. 33. SikaWrap Composite Fabrics
  34. 34. CFRP Composite System Characteristics• Precise Material Properties• Fully Corrosion resistant• High Strength• Extremely Lightweight• Range of Sizes Available for Optimum Design• Very easy application• Applicable on both uniform and non-uniform sections
  35. 35. Physical Properties of Epoxy Adhesives
  36. 36. Physical Properties of CFRP Materials
  37. 37. Steel vs Composites Steel Composites Low material cost High material costHigh installation cost Low installation cost corrosive Non- Corrosive Heavy Light weight Fabrication required No fabrication requiredHigh maintenance cost Low maintenance
  38. 38. Mechanical Properties of composites
  39. 39. Properties of SikaWrap FRP Fabrics
  40. 40. SIKA Wrap Application
  41. 41. SIKA CarboDur Application
  42. 42. Park Towers F10 Islamabad:– The structure needed an important strengthening and retrofit after recent earthquake– All structural cracks were epoxy injected, and many beams were strengthened in flexure at the basement level.
  43. 43. Beam Ready forEpoxy Injection
  44. 44. Beam & Slab Strengthening ByCFRP Composite System
  45. 45. Mobilink Head Office Building,Kulsum Plaza, Blue Area ,Islamabad
  46. 46. Mobilink Head Office Building
  47. 47. Mobilink Head Office Building
  48. 48. Mobilink Head Office Building
  49. 49. Mobilink Head Office Building
  50. 50. Mobilink Head Office Building
  51. 51. Repair of RC beams in Art Gallery Lahore
  52. 52. Refrences• Aslam, M., Mirza, W.H., Report (2010),“Rehabilitation & Retrofitting of R.C. Structures with Carbon Fibre Composite Systems”, SIKA Construction Chemicals Division, Imporient Chemicals (PVT) Ltd.Lahore, Pakistan• Khurram,N., (2009), “Performance of retrofitted reinforced concrete columns against pseudo cyclic load”, M.Sc. Research Thesis, University of Engineering and Technology, Lahore, Pakistan• Javed M. (2009), Seismic risk assessment of unreinforced brick masonary building system of northern Pakistan‟, Department of Civil engineering, U.E.T. Peshawar.• Khan Shahzada et al, „Experimental seismic performance and evaluation of unreinforced masonary buildings‟, Department of Civil Engineering, U.E.T. Peshawar.
  53. 53. Refrences• M. Eigawady et al, (july 2004),‟ A review of conventional seismic retrofitting techniques for URM‟, Amsterdam.• C. Amarnath, (april 2007),‟handbook on seismic retrofit of building‟, central public works department, Madras, India.• Charlotte. A. C. bouvier, (2003),‟Techniques for seismic retrofitting of concrete structures‟, MIT.• Andrew Smith and Thomas Redman (Jan. 2009), „A critical review of retroftting methods for unreinforced masonry structures‟, University of Bristol.