during the semester
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
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
OccupancyStructure 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-2 Damage 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-4 Limited Safety Range
The continuous range of damage states between the Life Safety Structural Performance Level (S-3) and the Collapse Prevention Structural Performance Level (S-5).
S-5 Collapse 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-6 Not 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