Presented by Muhammad Rizwan Riaz

2. RETROFITTING
(Seismic Design of Structures)
Presented by:
Muhammad Rizwan Riaz
(2011-MS-CES-01)

3. CONTENTS
The 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

4. 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.

5. Retrofitting Techniques

6. Classification of Retrofitting
1. Retrofitting of reinforced concrete (RC) structures
2. Retrofitting of masonry structures
RETROFITTING OF RC STRUCTURES
a) Strengthening Existing Members
• Reinforced Concrete Jacketing
• Steel Plate Bonding and Jacketing, Steel section caging; FRP
• Plate Bonding and Jacketing

7. Reinforced Concrete Jacketing

8. Reinforced Concrete Jacketing

9. Column with CFRP Wrap

10. Column with Steel Jacketing

11. Column with Steel Caging

12. Retrofitting Of RC Structures
b) Adding New members
• Shear walls
• Frames (moment resisting frames and braced frames)
• Bracings
• Buttresses

13. Shear Wall in Soft Story

14. Frames and shear wall

15. Steel Bracing in Soft Story

16. Steel Bracing

17. Introducing Buttresses

18. Retrofitting Of Masonary Structures
PRINCIPLE 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

19. Retrofitting Of Masonary Structures
METHODS FOR RETROFITTING OF MASONRY BUILDINGS
REPAIRING (IMPROVING EXISTING MASONRY STRENGTH)
• Stitching of cracks
• Grouting with cement or epoxy
• Use of CFRP (carbon fiber reinforced polymer) strips

20. Stitching of cracks in masonry walls

21. Repair of damaged member

22. Retrofitting Of Masonary Structures
RETROFITTING OF EQ. VULNERABLE BUILDINGS:
• External binding or jacketing
• Shotcreting
• Strengthening of wall intersections
• Strengthening by cross wall
• Strengthening by buttresses
• Strengthening of arches

23. Integral box action

24. Strengthening of wall intersections

25. Strengthening by cross wall

26. Strengthening by Buttresses

27. Strengthening of Arches

28. Economic Features of Various
Retrofitting Techniques

29. Economic Features of Various
Retrofitting Techniques

30. Need of Retrofitting in Pakistan
There are considerable number of reinforced concrete
structures in Pakistan that do not meet the requirements
of current design standards because of inadequate design
and/or construction errors and need structural upgrading
specially to meet the seismic design requirements.
After 2005 earthquake, the awareness and need of
seismic detailing has increased.
Retrofitting is the best solution to strengthen such
buildings without replacing them

31. New Trends in Retrofitting in
Pakistan
Strengthening Techniques
• Reinforcement Strengthening
• R.C Jacketing
• Externally Bonded Plates For Flexural Strengthening
• Shear/Compression Strengthening by Confinement
Carbon Fiber Reinforced Polymer (CFRP)
Composite System

32. New Trends in Retrofitting
SIKA 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)

33. CFRP Plate Systems

34. SikaWrap Composite Fabrics

35. 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

36. Physical Properties of Epoxy
Adhesives

37. Physical Properties of CFRP
Materials

38. Steel vs Composites
Steel Composites
Low material cost High material cost
High installation cost Low installation cost
corrosive Non- Corrosive
Heavy Light weight
Fabrication required No fabrication required
High maintenance cost Low maintenance

39. Mechanical Properties of
composites

40. Properties of SikaWrap FRP
Fabrics

41. SIKA Wrap Application

42. SIKA CarboDur Application

44. 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.

48. Beam Ready
for
Epoxy Injection

49. Beam
&
Slab
Strengthening
By
CFRP Composite
System

50. Mobilink Head Office Building,
Kulsum Plaza, Blue Area ,Islamabad

51. Mobilink Head Office Building

52. Mobilink Head Office Building

53. Mobilink Head Office Building

54. Mobilink Head Office Building

55. Mobilink Head Office Building

56. Repair of RC beams in Art Gallery Lahore

67. 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.

68. 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.