During the semester

• Introductions• Basics of earthquakes• History and Recording• Damaging Earthquakes and Understanding seismic exposure• Undertaking loss assessment

• Seismic analysis; and design and detailing (RCC and Masonry)

Recent Seismic Event

Recent Seismic Event

Try reading different tabs athttp://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/us2011ggbx.php#scitech

Alternate link

Which Plates?

Basics of Earthquake resistant Construction

Basics of Earthquake resistant Construction

Construction Type

• Infrastructure– How much critical? – Such as Bridges, Power Plants, Industrial sheds, etc.

• Housing – Occupancy levels (high or low?)– High density or Rural

Basics of Earthquake resistant Construction

Classify as:

• Foundation• Super-Structure

Design of both and compare stiffness and strength capacities

Basics of Earthquake resistant Construction

Basics of Earthquake resistant Construction

Foundation Damage

Basics of Earthquake resistant Construction

Foundation Damage Chuetsu earthquake-earthquake liquefaction

Basics of Earthquake resistant Construction

Ground Settlement

Basics of Earthquake resistant Construction

Foundation Damage

Basics of Earthquake resistant Construction

Foundation Weaknesses

• Liquefaction Temporary loss of strength in soil, which acts like a fluid.

• Differential settlementOver an area, non-uniform settlement of soil. Represented by different COMPACTION levels.

• Lateral Spread Movement /settlementLateral movement of loose soils

• LandslideIn slopes. Critical factors are- 1) Slope angle, 2) Soil type, etc.

• Ground Cracking Large crack or Lurching in form of irregular ground surface cracks

• SubsidenceVertical movement of ground surface. Rare.

Basics of Earthquake resistant Construction

Foundation WeaknessesLiquefaction

Basics of Earthquake resistant Construction

Foundation WeaknessesDifferential settlement

Basics of Earthquake resistant Construction

Foundation WeaknessesLateral Spread

Basics of Earthquake resistant Construction

Foundation WeaknessesLand Slide

Basics of Earthquake resistant Construction

Foundation WeaknessesGround Subsidence (Rare)

Structural Weakness

Structural Weakness

• Symmetry Centre of Gravity and Geometry.

• Regularity Vertical and Horiz.

• Openings Spacing and size

• Soft Storey effect Change in Stiffness, mass, strength and ductility

• Local eccentricity• Pounding

Control deflection

• OtherItems with a potential to fall. Such as- Long cantilevers, partition, badly fixed non-structural components

Basics of Earthquake resistant Construction

List of Codes and standards related to Earthquake Engineering

List– IS 1893:1984 Criteria for Earthquake Resistant Design of Structures – IS 1893(Part 1):2002 `Criteria for Earthquake Resistant Design of Structures : Part 1 General provisions and

Buildings– IS 1893(Part 4):2005 `Criteria for Earthquake Resistant Design of Structures: Part 4 Industrial Structures

Including Stack Like Structure– IS 4326:1993 Earthquake Resistant Design and Construction of Buildings - Code of Practice– IS 13827:1993 Improving Earthquake Resistance of Earthen Buildings – Guidelines– IS 13828:1993 Improving Earthquake Resistance of Low Strength Masonry Buildings – Guidelines– IS 13920:1993 Ductile Detailing of Reinforced Concrete Structures Subjected to Seismic Forces – Code of

Practice– IS 13935:1993 Repair and Seismic Strengthening of Buildings – Guidelines– IS 4967:1968 Recommendations for Seismic Instrumentation for River Valley Projects

– Eurocode 0: Basis of design– Eurocode1: Actions on structures – Eurocode 8 (Part 1 to 6): Earthuakes

• International building code, ASCE and collaboration codes

List of Codes and standards related to Earthquake Engineering

Internet Sources

– http://nisee.berkley.edu– http://www.bis.org.in/other/quake.htm– http://www.nicee.org/IITK-GSDMA_Codes.php – http://www.eurocodes.co.uk/EurocodeDetail.aspx?Eurocode=8 – http://en.wikipedia.org/wiki/International_Building_Code – http://www.asce.org/codes-standards/list/

Recommended Reading

Basics of Earthquake resistant Construction

Performance Levels and Ranges• Performance based design is a new approach used in

earthquake resistance design and construction. • FEMA document FEMA356 has more details• These are:

Basics of Earthquake resistant Construction

Performance Levels and Ranges

S-1 Immediate OccupancyS-2 Damage Control RangeS-3 Life SafetyS-4 Limited Safety RangeS-5 Collapse PreventionS-6 Not Considered

Basics of Earthquake resistant Construction

Performance Levels and RangesS-1

Immediate Occupancy

Structure retains the pre-earthquake design strength and stiffness, and is safe to occupy. Some minor structural repairs may be appropriate but not necessary to make the building safe to occupy.

S-2Damage

Control Range

This range may be desirable to minimize downtime and repair time, to protect equipment that depends on the survival of the structure for its functionality, or to preserve historic features of the building when its too costly to design for the S-1 damage state.

S-3 Life Safety

The building will retain at least some of its strength against collapse and should prevent loss of human life. However, there may be injuries and the building could potentially be damaged beyond the point of economical repair. Some business owners may desire to have a higher standard of design safety for their building. This is especially true in the case of business’ s that would suffer dramatically if business was interrupted after a seismic event. Obviously any building that collapses proposed significant risks to life safety and would not satisfy this design objective.

S-4Limited

Safety RangeThe continuous range of damage states between the Life Safety Structural Performance Level (S-3) and the Collapse Prevention Structural Performance Level (S-5).

S-5Collapse

Prevention

The building experience damage to structural components that weaken it so that it retains little or no lateral resistance against collapse either in part or in full. However, it will still continue to support its own weight provided that there is no further ground motion. Aftershock activity could cause collapse, but the initial event did not bring down the building.

S-6Not

Considered

A building rehabilitation that does not address structural performance at all, but instead focuses entirely on non-structural hazards associated with the building such as anchoring equipment and preventing damage to tenant property and improvments.

Basics of Earthquake resistant Construction

Summary- Note different collapse modes- Note different damage modes- Stiffness of Foundation and Stiffness of

Structure is important- Bad foundation or soil needs to be looked at,

so the structure performs as desired in an earthquake

Discuss

• 2nd Assignment• Book Reviews