2. Introduction
Ductile Concrete Moment
Resisting Frame Structure
(Parking Garage) that collapsed
during Northridge Earthquake
•Tremendous deformation Capacity in the Peripheral Columns
( Not Sufficiently Detailed to accommodate large Inelastic Deformations Demand…)
• So it is utmost important to have good and efficient structural control system.
4. WIND RESISTANT DESIGN
• Excitation is an applied Pressure or Force on the Facade
• Loading is Dynamic but Response is nearly Static for most Structures
• Structures deforms due to Applied force
• Deformations are monotonic (unidirectional)
• Structure is Designed to respond Elastically under Factored Loads
• The controlling Life Safety limit state is STRENGTH
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6. EARTHQUAKE RESISTANT DESIGN
• Excitation is an Applied Displacement at the Base
• Loading and Response are Truly Dynamic
• Structural Systems deforms as a result of Inertial Forces
• Structure is designed to respond Inelastically under Factored Loads
• Controlling Life Safety limit is DEFORMABILITY
• Enough Strength is provided to ensure that Inelastic deformation demands do
not exceed deformation Capacity.
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12. Structural Control Systems
• Energy absorption or dissipation devices
• by increasing stiffness (absorption)
• by improving dynamic performance (dissipation)
Methods to improve seismic response
conventional methods
1.Shear wall
2.Bracings Systems
3.Dual system
13. Structural Control Systems
Modern methods
1. Passive control systems
2. Active Control systems
3. Semi-active control systems
4. Hybrid control systems
14. Modern Methods
Base Isolation
• Introduces Flexibility in building
• Building is rested on flexible pads
• When earthquake strikes building does
not move
• It is suitable for hard soil only
15. Types of Base Isolator
Elastomeric and Lead Rubber Bearing
• Frequently used for base isolation
• Made of rubber sandwiched together within steel
• Very stiff and strong in vertical direction
• Flexible in horizontal direction
16. Types of Base Isolator
Spherical Sliding Isolation
• It uses bearing pads that have a curved surface and low
friction materials similar to Teflon
• During earthquake building is free to slide both
horizontally and vertically
• It returns to its original position as earthquake stops
30. Friction Damper
• Friction provides Excellent mechanisms for Energy Dissipation and has
been used from many years in automotive Brakes to dissipate Kinetic
Energy of Motion.
• The friction damper consists of diagonal brace elements with a friction interface at
their intersection point, which are connected together by horizontal and vertical link
elements.
• These link arms ensure that when the load is applied to a device via the braces is
sufficient to initiate slip on tension diagonal, then compression diagonal will also slip
an equal amount in opposite direction.
• The friction resistance of the device requires a normal force on the sliding interface,
and this is achieved through a bolt at the intersection of the diagonal arms.
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34. Metallic Damper
Dissipation of energy input to a structure from an earthquake is through inelastic
deformation of metals.
