Presentation on theme: "Seismic analysis and design of"— Presentation transcript:
1Seismic analysis and design of a structure in the UAEStudent Name:Huda Al-HayyassIman SalemNada Bakri Al NaserFatima Al-HosaniAmna Mohamed.Muna AbdullaAdvisor's Name: Prof. Ahmed Ghobarah
2Contents: Introduction. Earthquake. Historical Background. Methodology.Damages of earthquake.Gantt chart & Next week plan.Conclusion and Recommendation.
3IntroductionUAE is one of the developing countries, and it's famous of buildings, so earth quake will affect seriously in this buildings. In the last few years Earthquakes strike in the UAE as evidenced by the damaging earthquakes near :Masafi in early 2002,The magnitude 5.1.Dubai 27/2005 ,The magnitude 6.1.Problems:UAE didn't have organization for recording earthquake values, its only uncoordinated efforts.UAE didn't have Seismic Design Codes.
4The municipality compulsion to use Seismic Design Codes such as: New ZealandBritish CodeUniform Building CodeNEHRPInternational Building CodeEurocode 8Objectives:Apply earthquake engineering concepts to study, analyze and design a reinforced concrete structure in the UAE .develop anew special codes for UAE.
9The Earthquake magnitudes were known and recorded in UAE: LocationYearunknownDubai, Abu-Dhabi1924192519305.1North Emirates19945.91999Masafi2001
10The Earthquake magnitudes were known and recorded in UAE: LocationYear4-5.1Masafi, Dubai, Sharjah, Ajman, Ras Al-Khaima, & Um-Qwain.2002unknownRas Al Khaimah2003FujairahMasafi2.7Dibba/Fujerah20046.1Dubai2005
11Comparing the magnitude and effects of earthquakes. Earthquake EffectsRichter Scale MagnitudeBasically unable to be felt, but is recorded by seismology labs.Less than 3.5Usually felt, but causes minimal damage.Between 3.5 and 5.4May cause slight damage to well-designed buildings, but can cause significant damage to poorly built structures over a small region.Between 5.4 and 6.0Destructive over an area up to 60 miles in diameterBetween 6.1 and 6.9Considered a major earthquake. Causes serious damage over a larger area.Between 7.0 and 7.9Very significant earthquake. Causes serious damage over an area over 100 miles in diameter.Greater than 8.0
12MethodologyIn order to design and construct a structure in such regions, seismic hazard analysis must be predicted. (By determining the peak ground acceleration [PGA]).Seismic hazard analysis:The probability of future seismic loading that the structure is likely to be exposed to during its lifetime.
13Seismic Hazard Analysis Methods Deterministic approach:Used to determine the maximum credible E.Q motion at a given site.It’s simple and usually used when:The tectonic features of the region are well defined.The seismic activity is relatively high.Probabilistic approach:Quantifies the uncertainly and take into consideration the probability of E.Q occurrence.It’s used to predict and forecast the implication of future uncertainly
14Comparison between the two methods The probabilistic approach takes into account:The uncertainties in the level of magnitude of E.Q.The hypocentral location.Its recurrence relation and its attenuation relation.All these points gives more realistic values for E.Q parameters for the probabilistic approach as compared to the deterministic approach.In our project, the probabilistic approach will be used.
15Steps of probabilistic seismic hazard analysis The main steps and parameters of the probabilistic seismic hazard assessment :Historical and instrumental seismic data.Seismic source model that based on geological and seismological.Estimated recurrence relationships and the assessment of the maximum magnitudes.Attenuation of the strong ground motion.Recurrence forecasting.
16Attenuation Relations There are many factors affects the reduction amount of PGA, which are:Magnitude of E.Q.Length of E.Q (period).Distance of site considered from E.Q hypo central.Soil characteristics of the site.Frequency of the signal reaches the building.Natural frequency of the building.
17PGA (cm/s2) with a 10% probability of exceedance 975 yrs return period475 yrs return period
18Seismic Zoning of UAE Soil conditions. PGA. Zones Analysis:Soil conditions.PGA.The long time span, the better the seismic hazard assessment.
21Philosophy of Design Process In designing a regular building subjected to an earthquake, we design for:Small E.Q [10% probability of exceedance within 475 years period]Building should not be affected(No cracks will occur)
22Philosophy of Design Process, (cont.) Median E.Q [10% probability of exceedance within 975 years period]Some cracks may occurred,But can be repair
23Philosophy of Design Process, (cont.) Extreme E.Q [10% probability of exceedance within 1900 years period]Major damages on the buildingBut the building will not collapseor fail. (No People will be killed)