Presentation on theme: "Seismic analysis and design of a structure in the UAE Student Name: Huda Al-Hayyass Iman Salem Nada Bakri Al Naser Fatima Al-Hosani Amna Mohamed. Muna."— Presentation transcript:
Seismic analysis and design of a structure in the UAE Student Name: Huda Al-Hayyass Iman Salem Nada Bakri Al Naser Fatima Al-Hosani Amna Mohamed. Muna Abdulla Advisor's Name: Prof. Ahmed Ghobarah
Contents: Introduction.Introduction. Earthquake.Earthquake. Historical Background.Historical Background. Methodology.Methodology. Damages of earthquake.Damages of earthquake. Gantt chart & Next week plan.Gantt chart & Next week plan. Conclusion and Recommendation.Conclusion and Recommendation.
Introduction UAE 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. o Masafi in early 2002,The magnitude 5.1. oDubai 27/2005,The magnitude 6.1. Problems: Problems: UAE didn't have organization for recording earthquake values, its only uncoordinated efforts. UAE didn't have Seismic Design Codes.
The municipality compulsion to use Seismic Design Codes such as: New Zealand British Code Uniform Building Code NEHRP International Building Code Eurocode 8 Objectives: Apply earthquake engineering concepts to study, analyze and design a reinforced concrete structure in the UAE. develop anew special codes for UAE.
The Earthquake magnitudes were known and recorded in UAE: MagnitudeLocationYear unknownDubai, Abu-Dhabi1924 unknownDubai, Abu-Dhabi1925 unknownDubai, Abu-Dhabi1930 5.1North Emirates1994 5.9North Emirates1999 unknownMasafi2001
The Earthquake magnitudes were known and recorded in UAE: MagnitudeLocationYear 4-5.1Masafi, Dubai, Sharjah, Ajman, Ras Al-Khaima, & Um- Qwain. 2002 unknownRas Al Khaimah2003 unknownFujairah2003 unknownMasafi2003 2.7Dibba/Fujerah2004 6.1Dubai2005
Comparing the magnitude and effects of earthquakes. Earthquake Effects Richter Scale Magnitude Basically unable to be felt, but is recorded by seismology labs. Less than 3.5 Usually felt, but causes minimal damage.Between 3.5 and 5.4 May cause slight damage to well-designed buildings, but can cause significant damage to poorly built structures over a small region. Between 5.4 and 6.0 Destructive over an area up to 60 miles in diameterBetween 6.1 and 6.9 Considered a major earthquake. Causes serious damage over a larger area. Between 7.0 and 7.9 Very significant earthquake. Causes serious damage over an area over 100 miles in diameter. Greater than 8.0
Methodology In 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.
Seismic Hazard Analysis Methods Deterministic approach: Used to determine the maximum credible E.Q motion at a given site. Its 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. Its used to predict and forecast the implication of future uncertainly
Comparison 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.
Steps 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.
Attenuation 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.
PGA (cm/s 2 ) with a 10% probability of exceedance 975 yrs return period475 yrs return period
Seismic Zoning of UAE Zones Analysis: –Soil conditions. –PGA. –The long time span, the better the seismic hazard assessment.
Philosophy 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)
Philosophy of Design Process, (cont.) –Median E.Q [10% probability of exceedance within 975 years period] Some cracks may occurred, But can be repair
Philosophy of Design Process, (cont.) –Extreme E.Q [10% probability of exceedance within 1900 years period] Major damages on the building But the building will not collapse or fail. (No People will be killed)