Seismic analysis and design of a structure in the UAE Student Name: Huda Al-Hayyass Iman Salem Nada...

Seismic analysis and design ofSeismic analysis and design of a structure in the UAEa structure in the UAE

Student Name:Student Name:

Huda Al-HayyassHuda Al-Hayyass

Iman SalemIman Salem

Nada Bakri Al NaserNada Bakri Al Naser

Fatima Al-HosaniFatima Al-Hosani

Amna Mohamed.Amna Mohamed.

Muna AbdullaMuna Abdulla

Advisor's Name: Prof. Ahmed Ghobarah

ContentsContents::

• 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.

IntroductionIntroduction UAE is one of the developing countries, and it's famous of UAE is one of the developing countries, and it's famous of

buildings, so earth quake will affect seriously in this buildings, so earth quake will affect seriously in this buildings. In the last few years Earthquakes strike in the buildings. In the last few years Earthquakes strike in the UAE as evidenced by the damaging earthquakes near :UAE as evidenced by the damaging earthquakes near :

o Masafi in early 2002,The magnitude 5.1.Masafi in early 2002,The magnitude 5.1.o Dubai 27/2005 ,The magnitude 6.1.Dubai 27/2005 ,The magnitude 6.1.

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.

Emirate's geology:

How and why Seismic happen in UAE:

How and why Seismic happen in UAE:

Earthquake Observations Centers

The Earthquake magnitudes were known and recorded in UAE:

YearLocationMagnitude

1924Dubai, Abu-Dhabi unknown

1925Dubai, Abu-Dhabi unknown

1930Dubai, Abu-Dhabi unknown

1994North Emirates 5.1

1999North Emirates 5.9

2001Masafiunknown

The Earthquake magnitudes were known and recorded in UAE:

YearLocationMagnitude

2002Masafi, Dubai, Sharjah, Ajman, Ras Al-Khaima, & Um-

Qwain.

4-5.1

2003Ras Al Khaimah unknown

2003Fujairah unknown

2003Masafi unknown

2004Dibba/Fujerah 2.7

2005Dubai6.1

Comparing the magnitude and effects of earthquakes .

Richter Scale Magnitude

Earthquake Effects

Less than 3.5Basically unable to be felt, but is recorded by

seismology labs.

Between 3.5 and 5.4Usually felt, but causes minimal damage.

Between 5.4 and 6.0May cause slight damage to well-designed buildings,

but can cause significant damage to poorly built structures over a small region.

Between 6.1 and 6.9Destructive over an area up to 60 miles in diameter

Between 7.0 and 7.9Considered a major earthquake. Causes serious

damage over a larger area.

Greater than 8.0Very significant earthquake. Causes serious damage

over an area over 100 miles in diameter.

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.

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

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/s2) with a 10% probability of exceedance

975 yrs return period 475 yrs return period

Seismic Zoning of UAE

Zones Analysis:

– Soil conditions.

– PGA.

– The long time span, the better the seismic hazard assessment.

March 2002 Fujirah earthquake

Philosophy of Design ProcessPhilosophy 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, Philosophy of Design Process, (cont.)(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)

Nonlin ProgramNonlin Program