1. SEISMIC RETROFITTING OF CONCRETE BUILDINGS
GUIDED BY
AMBILI RAVI,
LECTURER,
DEPT. OF CIVIL ENGG,
SNGCE.
PRESENTED BY
ANU THAMPY,
SEM -7,
ROLL NO-9,
SNGCE.

2. INTRODUCTION

3. EARTHQUAKE GENERATION
EARTHQUAKES
EARTHQUAKE GENERATION

4. SEISMIC RETROFITTING NEED FOR RETROFITTING BUILDING DEFICIENCIES
STEPS TAKEN PRIOR TO RETROFITTING

5. NEED FOR RETROFITTING \ MAKES BUILDING SAFER AND LESS PRONE TO DAMAGE
CONSTUCTION TECHNIQUES ARE IMPROVED
DURABILITY AND AESTHETIC APPEARANCE ARE REDUCED
AFTER DAMAGE
DEMANDS ON EXISTING STRUCTURES ARE INCREASING
UNEXPECTED EXTRA LOADS ARE TO BE CARRIED
MAKES IMPROVEMENTS TO AN EXISTING BUILDING

6. BUILDING DEFICIENCIES
PLAN IRREGULARITIES.
VERTICAL IRREGULARITIES

7. PLAN IRREGULARITY
Torsional irregularity due to plan asymmetry and eccentric mass from water tank.
Re-entrant corners in U-,L- and T-shaped building.
Diaphragm discontinuity due to openings or staggered floors along with absence of collector elements.
Out-of-plane offset for floating columns along perimeter.
Nonparallel lateral load resisting systems.

8. VERTICAL IRREGULARITIES
Stiffness irregularity , extreme soft storey due to open ground storey.
Mass irregularity.
Vertical geometric irregularity from set-back towers.
In-plane discontinuity for floating columns along perimeter.
Weak storey for open ground storey.

9. VARIOUS STEPS TAKEN PRIOR TO RETROFITTING
SCREENING
EVALUVATION
RETROFIT

10. TRADITIONAL APPROACHES TO SEISMIC RETROFITTING

11. INNOVATIVE APPROACHES TO SEISMIC RETROFITTING
STIFFNESS REDUCTION.
DUCTILITY INCREASE.
DAMAGE CONTROL STRUCTURES.
ACTIVE CONTROL.

12. STIFFNESS REDUCTION BY THE PRINCIPLE OF SPRINGS IN SERIES

13. Seismic Isolator Placement Alternates

14. LEAD RUBBER BEARING
(Top Mounting Plate Not Shown)
Energy Dissipation Core
Cover Rubber
Internal Rubber Layers
Steel Reinforcing Plate
Bottom Mounting Plate
It is made from layers of rubber sandwiched together with layers of steel.
The bearing is very stiff and strong in the vertical direction but flexible in the horizontal direction.

15. WORKING OF BASE ISOLATION SYSTEMS (BUILDING WITH BASE ISOLATION)
BUILDING WITHOUT BASE ISOLATION
WORKING OF BASE ISOLATION SYSTEMS (BUILDING WITH BASE ISOLATION)

16. DAMAGE CONTROLLED STRUCTURE

17. X-BRACED FRICTION DAMPER

18. CFRP APPLICATION ON A COLUMN

19. CONCLUSION Makes buildings more resistant to earthquakes.
Retrofit techniques are applicable for other natural hazards.
Give safety to the occupants.
Cost effective.
Still, no such a technique is completely earthquake proof.
Challenging to select a technique.

20. REFERENCE
Giuseppe Oliveto, Massime Marletta,(2005), Seismic Retrofitting of Reinforced Concrete Buildings using Traditional and Innovative Techniques, ISET Journal of Earthquake Technology, 454, pp
Steven.L.Kramer,(2000), Geotechnical Earthquake Engineering, En., Academic Press, New York, 1988.

21. THANK YOU