07-02-2010, 07:45 PM
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SEISMIC RETROFITTING OF CONCRETE BUILDINGS
SEISMIC RETROFITTING
NEED FOR RETROFITTING
BUILDING DEFICIENCIES
STEPS TAKEN PRIOR TO RETROFITTING
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
BUILDING DEFICIENCIES
PLAN IRREGULARITIES.
VERTICAL IRREGULARITIES
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.
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.
INNOVATIVE APPROACHES TO SEISMIC RETROFITTING
STIFFNESS REDUCTION.
DUCTILITY INCREASE.
DAMAGE CONTROL STRUCTURES.
ACTIVE CONTROL.
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
