Earthquake Engineering 2011 lec-01

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First Lecture of Sunday 12-03-2011by : tharwat Sakr

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  • 1.EARTHQUAKEENGINEERING 1.1. Introduction1.1.1. Definitions1.1.2. Earthquake Hazards1.1.3. Course Layout

2. 1.1.1. DEFINITIONS Earthquake Engineering can be defined as the branch of engineering devoted to mitigating earthquake hazards. In this broad sense, earthquake engineering covers the i h investigation and solution of the problems created b i i d l i f h bl d by damaging earthquakes, and consequently the work involved in the practical application of these solutions, i.e. in planning, designing, constructing and managing earthquake resistant structures and earthquakeresistant facilities. Scope Seismicity ,Nature, Measures and Recording of earthquakes. Planning for Seismic Risk Assessment & Mitigation Analysis, Design and Construction of Earthquake Resistant Structures Evaluation of Buildings for Earthquake Resistance Retrofitting f Earthquake d R t fitti of E thk damaged St td Structures Earthquake Management and Security 3. 1.1.1. DEFINITIONS An Earthquake isthemotionorvibration,sometimesviolent,oftheearthssurfacethatfollows a release of energy in the earths crust. This energy can be generated by a suddendislocationofsegmentsofthecrust,byavolcaniceruption,orevenby sudden dislocation of segments of the crust by a volcanic eruption or even by manmadeexplosions. Sources of Ground Movements Tectonic Earthquakes Volcanoesl Explosions Collapse of Mines & Large Reservoirs Tsunami 4. 1.1.2. EARTHQUAKE HAZARDS Failure of Slopes 5. 1.1.2. EARTHQUAKE HAZARDS Occurrence of Fire 6. 1.1.2. EARTHQUAKE HAZARDS Building Collapse 7. 1.1.2. EARTHQUAKE HAZARDS Building Collapse 8. 1.1.2. EARTHQUAKE HAZARDS Building Collapse 9. 1.1.2. EARTHQUAKE HAZARDS Bridge Collapse 10. 1.1.2. EARTHQUAKE HAZARDS Land Slide 11. 1.1.2. EARTHQUAKE HAZARDS Disturbance 12. 1.1.2. EARTHQUAKE HAZARDS Specific Failures Collapse of the first storey and damagedue to pounding between adjacentCollapse of a high-rise building because of buildings during the Kocaelifailure of the columns at the first storeyearthquake, Turkey, August 17, 1999,during the Chi-Chid i th Chi Chi earthquake, T i thk Taiwan,Magnitude 7 4 7.4September 20, 1999, Magnitude 7.6 13. 1.1.2. EARTHQUAKE HAZARDSMay 2008 China Earthquakey q Date : May 12, 2008, 14:28 Magnitude: 8 0 Richter Scale Earthquake8.0 Location : Sichuan, China Death: 69,016 Missing:18,627 Injured: 373,573Displaced :15,006,341:15 006 341 School Destroyed : 6,898 Rescue workers : 130,000 Prof.Dr. Osman ShaalanEarthquake EngineeringDr. Tharwat Sakr 14. 1.1.2. EARTHQUAKE HAZARDS4.5M homes destroyed4 5M h d d Some counties completelywiped off the mapMore than 11M people DisplacedAt this momentProf.Dr. Osman Shaalan Earthquake Engineering Dr. Tharwat Sakr 15. 1.1.2. EARTHQUAKE HAZARDSThousands of tents are neededFood and water are neededMedical supplies are neededProf.Dr. Osman ShaalanEarthquake Engineering Dr. Tharwat Sakr 16. 1.1.3. COURSE LAYOUT1 Introduction2 Seismicity : Nature, Measures and Characteristics ofEarthquakes3 Methods of Earthquake Analysis of Structures yTime HistoryResponse SpectrumEquivalent Static Loads According to the Egyptian Code UBC - IBC4 Earthquake Design of Structures5 P ti l and A hit t l C Practical d Architectural Considerations id ti 17. EARTHQUAKEENGINEERING1.2. N Nature of f Earthquakes 1.2.1. Causes of Earthquakes 1.2.2. Faults 1.2.3. Earthquake Effects 18. 1.2.1. Causes of EarthquakesTectonic Earthquakesare caused by the sudden dislocation of large rock masses alonggeological faults within the earths crust. The Earth is formed ofseveral l l layers that h h have very diffdifferent physical and chemical h i ld h i lproperties. The outer layer, which averages about 70 kilometersin thickness, consists of about a dozen large, irregularly shapedplates that slide over under and past each other on top of theover,partly molten inner layer .Most earthquakes occur at theboundaries where the plates meet . Plate Tectonic InteractionsFlash movieDr. Osman Shalan Dr. Tharwat Sakr 19. 1.2.1. Causes of EarthquakesVolcanic EarthquakesEarthquakes that can be reasonably associated with volcanoes are relatively rare and fall into three categories:(i) volcanic explosions, (ii) shallow earthquakes from magma movements, and (iii) sympathetic tectonic earthquakes Dr. Osman Shalan Dr. Tharwat Sakr 20. 1.2.1. Causes of EarthquakesExplosions Earthquakes may be producedqypbytheundergrounddetonation of chemical ornuclear devices When a devices.nuclear device is detonated ina borehole underground,enormous nuclear energy isreleased .Dr. Osman ShalanDr. Tharwat Sakr 21. 1.2.1. Causes of EarthquakesCollapse Earthquakes Collapse earthquakes are small earthquakes occur in regions of underground caverns and mines. The immediate cause of ground shaking is the sudden collapse of the roofg g p of the mine or cavern. Dr. Osman Shalan Dr. Tharwat Sakr 22. 1.2.1. Causes of EarthquakesLarge Reservoir-induced EarthquakesReservoir-The idea that earthquakes might be triggered by impounding q ggg y p gsurface water is not new. The first detailed evidence of such aneffect came with the filling of Lake Mead behind Hoover Dam(height 221 m. After impounding began , reports of local shakingbecame prevalent.bl tDr. Osman Shalan Dr. Tharwat Sakr 23. 1.2.1. Causes of EarthquakesTsunamiUnderwater earthquakes,volcanoes, or landslidescan produce a tsunami ortidal wave. This wave cantravel veryrapidlythousands of miles acrossthe ocean. In deep waterthe tsunami may only raisethe ocean level by a fewcentimeters,centimeters hardly enoughto notice. But as itapproachesland,theshallower water causes thewave to build in height toas much as 10-20 metersor more and suddenlyflood coastal areas Dr. Osman Shalan Dr. Tharwat Sakr 24. 1.2.2. FaultsDefinition A fault is a fracture within some particular rocky mass within the earths crust. Th d h and h The depth d length of faults vary greatly. Faults may range in length from few meters to many kilometers and are drawn on a geological map as continuous or broken lines. Earthquakes are caused byq y active faults, that is, faults along faults which the two sides of the fracture move with respect to each other. S an earthquake i h th So, th k is caused by the sudden movement of the two sides of a fault with respect to another .Dr. Osman ShalanDr. Tharwat Sakr 25. 1.2.2. FaultsActive FaultsProf.Dr. Osman Shaalan Dr. Tharwat Sakr 26. 1.2.2. FaultsTectonic PlatesDr. Osman Shalan Dr. Tharwat Sakr 27. 1.2.2. Faults Types of Faultsa) Normal faults These occur in response to pulling or tension: the overlying bl k ih l i block moves down the dip of the fault plane. movie b) Thrust (reverse) faults These occur in response to squeezing or compression: the overlying block moves up the dip y gp p of the fault plane. moviec) Strikeslip (lateral) faults Strike These occur in response to either type of stress: th bl k move tf tthe blocks horizontally past one another . movieProf.Dr. Osman Shaalan Earthquake Engineering Dr. Tharwat Sakr 28. 1.2.2. Faults Earthquake Generation (Theory of Elastic ReboundRebound) ElasticReboundModelofEarthquake Elastic Rebound Model of EarthquakemovieProf.Dr. Osman Shaalan Earthquake Engineering Dr. Tharwat Sakr 29. 1.2.2. Faults Earthquake Focus The point on the fault where rupture initiates is referred to as the f h focus or h hypocentert of an earthquake. The hypocenter of an earthquake is described byq y its depth in kilometers, its map location in latitude and The term epicenter is the longitude, its date and time point on the earths surface earth s of occurrence, and i f d itsdirectly above the magnitudehypocenterProf. Dr. Osman Shaalan Earthquake EngineeringDr. Tharwat Sak 30. 1.2.3. Earthquake Effects How do Earthquakes affect Structures? q 1 By inertial forces generated b severe d by ground shaking Overturning collapse of a high-rise building Chi Chi Chi-Chi earthquake, Taiwan, September 20,1999, Magnitude 7.6Prof.Dr. Osman ShaalanEarthquake EngineeringDr. Tharwat Sakr 31. 1.2.3. Earthquake Effects How do Earthquakes affect Structures? q2.Byearthquake inducedfires: i d d fi Damage caused by the earthquake induced fires Hanshin (Kobe) earthquake, January 17, 1995, Japan, Magnitude 6.9Prof.Dr. Osman Shaalan Earthquake Engineering Dr. Tharwat Sakr 32. 1.2.3. Earthquake Effects How do Earthquakes affect Structures? q3. By changing the physical properties of the foundation soils such as Liquefaction: Overturning due to liquefactiong q Damage due to liquefaction Kocaeli earthquake, Turkey, 1999, Magnitude 7.4 1964 Niigata, Japan, earthquake.Prof.Dr. Osman ShaalanEarthquake EngineeringDr. Tharwat Sakr 33. 1.2.3. Earthquake Effects How do Earthquakes affect Structures? q 4. By direct fault displacement at the site of a structure:Prof.Dr. Osman ShaalanEarthquake EngineeringDr. Tharwat Sakr 34. 1.2.3. Earthquake Effects How do Earthquakes affect Structures? q 5. By landslides, or other movement:Prof.Dr. Osman ShaalanEarthquake Engineering Dr. Tharwat Sakr 35. 1.2.3. Earthquake Effects How do Earthquakes affect Structures? q 6. By seismic sea waves (tsunamis) or fluid motions inreservoirs and lakes (seiches):Prof.Dr. Osman ShaalanEarthquake Engineering Dr. Tharwat Sakr 36. 1.2. Nature of EarthquakesQuestions (refer to Project Group Page Assignment (1))Page(1Prof. Dr. Osman ShaalanEarthquake EngineeringDr. Tharwat Sakr