**5.2. Ground response**

**5.1. Instrumentation and data acquisition**

stations or El Sakakini building floors/

**•** Zero correction to the total 10-minnoise at time domain

18 Engineering Seismology, Geotechnical and Structural Earthquake Engineering

**•** Subdivision of each 10-minsignal into fifteen 1-min sub-windows,

followed the following steps:

sponse of El-Sakakini Palace.

used as reference site).

domain using a Fast Fourier transform,

A high dynamic range Seismograph (Geometrics ES-3000 see Figure 13) mobile station with triaxial force balance accelerometer (3 channels), orthogonally oriented was used. The station was used with 4Hz sensors to record the horizontal components in longitudinal and transverse directions in addition to the vertical components. For the data acquisition and processing we

**•** Recording 10-min of ambient noise data using a mobile station moving among variable soil

**Figure 13.** High dynamic range ES-3000 Geometrics mobile station and triaxial geophone used 4 Hz to drive soil re‐

Each of these series was tapered with a 3-sec hanning taper and converted to the frequency

**•** Site response spectrum for a given soil site (or certain floor) is given by dividing the average spectrum of this site over the spectrum of the reference site. The reference site is choose carefully in the site as deepest and calmest station in the basement floor with least soil response (usually we choose a certain basement floor location with least soil response to be

**•** Smoothing the amplitude spectrum by convolution with 0.2-Hz boxcar window,

Figure 14 shows the locations of microtremors stations used to determine the ground response at EL Sakakini Palace area. The predominant frequency of the ground at EL Sakakini Palace is about 3 Hz (see Figure 15 & Table 1), a value almost identical to the theoretical estimation according to Kennett and Kerry (1979) (Figure 16 & Table 4). The amplification factor is about 2, which is relatively low.

**Figure 14.** Ambient noise measurement locations

**Site Fundamental frequency (Hz) Amplification Factor**

Seismic Hazard Analysis for Archaeological Structures — A Case Study for EL Sakakini Palace Cairo, Egypt

S1 3 2.5 S2 3.2 2 S3 3 1.6 S4 3 1.6 S5 3 2

> **S-wave velocity (m/s)**

10 1300 315 (350?) 1.6 7 25 1300 500 1.7 15 >10.5 2000 700 2 100

0 1 2 3 4 5 6 7 8 9 1 0 1 1

0 1 2 3 4 5 6 7 8 9 1 0 1 1 Fre q u e n cy (H Z)

**Figure 16.** Theoretical ground response analysis at EL Sakakini Palace using Kennett at al. (1979) method.

3000 1200 2.5 200

**Dry Density (gm/c.c)**

**Quality factor Qs**

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21

1

2

3

4

5

6

**Table 3.** Fundamental frequencies and amplification factors at five locations

**(m/s)**

**Table 4.** Parameters used for the Kennett and Kerry method (1979)

**Thickness P-wave velocity**

1

2

3

Amplification Factor

4

Figure 15. Microtremors soil response for El Sakakini Palace Sites S1 to S5. **Figure 15.** Microtremors soil response for El Sakakini Palace Sites S1 to S5.

Seismic Hazard Analysis for Archaeological Structures — A Case Study for EL Sakakini Palace Cairo, Egypt http://dx.doi.org/10.5772/54395 21


**Table 3.** Fundamental frequencies and amplification factors at five locations


**Table 4.** Parameters used for the Kennett and Kerry method (1979)

Figure 15. Microtremors soil response for El Sakakini Palace Sites S1 to S5.

0

**Figure 15.** Microtremors soil response for El Sakakini Palace Sites S1 to S5.

1

2

**Amplification Factor**

3

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

0 1 2 3 4 5 6 7 8 9 10

20 Engineering Seismology, Geotechnical and Structural Earthquake Engineering

S1

0

0

0

0 1 2 3 4 5 6 7 8 9 10

0

1

2

3

4

5

S11

S5

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0.4

0.8

1.2

**Amplification Factor**

1.6

S5S3 S4

2

1

2

**Amplification Factor**

3

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

S10

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0

1

2

3

4

5

0 1 2 3 4 5 6 7 8 9 10

S2

0

0

1

2

3

4

5

1

2

3

4

5

1

2

3

4

5

0

0

0.4

0.8

1.2

**Amplification Factor**

1.6

2

1

2

**Amplification Factor**

3

**Figure 16.** Theoretical ground response analysis at EL Sakakini Palace using Kennett at al. (1979) method.

#### **5.3. Building response**

The El Sakakini building is composed of a basement and five floors the upper two being wooden. Figures 17 to 19 show the locations of recording stations used to drive El Sakakini building response. Figures 21 to 26 and Table 5 show the recorded natural frequency of vibration for each floor. All floors show nearly the same resonance frequency with the soil (3-4 HZ). The wooden floors (Figure 25 & 26) show very high amplification and multi peak as fundamental and other harmonics. The fundamental natural frequency of vibration is always the most important frequency that insert the maximum earthquake vibration energy into structure. However when we find other mode of vibrations with big amplification factors we consider this as a warning that this structure may suffer from vibration. This could be very good warning for its unstable performance during vibration.

**Figure 18.** Location of stations at 2nd floor of El-Sakakini Palace.

Seismic Hazard Analysis for Archaeological Structures — A Case Study for EL Sakakini Palace Cairo, Egypt

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**Figure 17.** Location of stations at the basement of EL-Sakakini Palace.

Seismic Hazard Analysis for Archaeological Structures — A Case Study for EL Sakakini Palace Cairo, Egypt http://dx.doi.org/10.5772/54395 23

**Figure 18.** Location of stations at 2nd floor of El-Sakakini Palace.

**5.3. Building response**

The El Sakakini building is composed of a basement and five floors the upper two being wooden. Figures 17 to 19 show the locations of recording stations used to drive El Sakakini building response. Figures 21 to 26 and Table 5 show the recorded natural frequency of vibration for each floor. All floors show nearly the same resonance frequency with the soil (3-4 HZ). The wooden floors (Figure 25 & 26) show very high amplification and multi peak as fundamental and other harmonics. The fundamental natural frequency of vibration is always the most important frequency that insert the maximum earthquake vibration energy into structure. However when we find other mode of vibrations with big amplification factors we consider this as a warning that this structure may suffer from vibration. This could be very

good warning for its unstable performance during vibration.

22 Engineering Seismology, Geotechnical and Structural Earthquake Engineering

**Figure 17.** Location of stations at the basement of EL-Sakakini Palace.

**Figure 20.** High dynamic range ES-3000 Geometrics mobile station and triaxial geophone used 4 Hz to drive structure

Seismic Hazard Analysis for Archaeological Structures — A Case Study for EL Sakakini Palace Cairo, Egypt

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25

response of El-Sakakini Palace.

**Figure 19.** Location of stations at the 3rd floor.

Seismic Hazard Analysis for Archaeological Structures — A Case Study for EL Sakakini Palace Cairo, Egypt http://dx.doi.org/10.5772/54395 25

F3-1

24 Engineering Seismology, Geotechnical and Structural Earthquake Engineering

**Figure 19.** Location of stations at the 3rd floor.

F3-2 F3-4

F3-3 F3-5

F3-6

**Figure 20.** High dynamic range ES-3000 Geometrics mobile station and triaxial geophone used 4 Hz to drive structure response of El-Sakakini Palace.

Figure 21. Natural frequency of vibration for basement floor.

Figure 22. Natural frequency of vibration for the 1st floor.

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

F1-5

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

F1-9

0 1 2 3 4 5 6 7 8 9 10

Seismic Hazard Analysis for Archaeological Structures — A Case Study for EL Sakakini Palace Cairo, Egypt

F1-2

0 0.4 0.8 1.2 1.6 2

0

0 0.4 0.8 1.2 1.6 2

**Amplification Factor**

1

2

**Amplification Factor**

3

**Amplification Factor**

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

F1-7

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

F1-10

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

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F1-3

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

F1-4

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

F1-8

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

**Figure 22.** Natural frequency of vibration for the 1st floor.

0 1 2 3 4 5 6 7 8 9 10

F1-1

0 0.4 0.8 1.2 1.6 2

0

0 0.4 0.8 1.2 1.6 2

**Amplification Factor**

1

2

**Amplification Factor**

3

**Amplification Factor**

0

0

0 0.5 1 1.5 2 2.5

**Amplification Factor**

1

2

**Amplification Factor**

3

0.4

0.8

**Amplification Factor**

1.2

1.6

**Figure 21.** Natural frequency of vibration for basement floor.

**Frequency (Hertz)**

Figure 22. Natural frequency of vibration for the 1st floor.

**Figure 22.** Natural frequency of vibration for the 1st floor.

Figure 21. Natural frequency of vibration for basement floor.

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

Basement 11

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

Basement 4

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

Basement 7

0 1 2 3 4 5 6 7 8 9 10

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

Basement 10

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

Basement 1

0

**Figure 21.** Natural frequency of vibration for basement floor.

0 0.5 1 1.5 2 2.5

0 0.5 1 1.5 2 2.5

**Amplification Factor**

**Amplification Factor**

0

0.4

0.8

1.2

**Amplification Factor**

1.6

2

1

2

3

4

5

0

0.4

0.8

**Amplification Factor**

1.2

1.6

26 Engineering Seismology, Geotechnical and Structural Earthquake Engineering

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

Basement 5

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

Basement 8

0 1 2 3 4 5 6 7 8 9 10

0 1 2 3 4 5 6 7 8 9 10

Basement 2

0

0 0.4 0.8 1.2 1.6 2

0 0.5 1 1.5 2 2.5

**Amplification Factor**

**Amplification Factor**

0 0.5 1 1.5 2 2.5

1

2

3

**Amplification Factor**

4

5

0

0.4

0.8

**Amplification Factor**

1.2

1.6

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

Basement 6

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

Basement 9

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

Basement 12

0 1 2 3 4 5 6 7 8 9 10

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

Basement 3

0 0.4 0.8 1.2 1.6 2

0

0 0.4 0.8 1.2 1.6 2

0 0.4 0.8 1.2 1.6 2

**Amplification Factor**

**Amplification Factor**

0.4

0.8

**Amplification Factor**

1.2

1.6

**Amplification Factor**

Figure 24. Natural frequency of vibration for the 3rd floor.

Figure 24. Natural frequency of vibration for the 3rd floor.

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

F3-5

F3-5

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

F3-6

F3-6

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

F3-3

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F3-3

0 1 2 3 4 5 6 7 8 9 10

0 1 2 3 4 5 6 7 8 9 10

w 1-2

w 1-2

0 1 2 3 4 5 6 7 8 9 10

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

**Amplification Factor**

**Amplification Factor**

**Amplification Factor**

**Amplification Factor**

0 1 2 3 4 5 6 7 8 9 10

Seismic Hazard Analysis for Archaeological Structures — A Case Study for EL Sakakini Palace Cairo, Egypt

F3-2

F3-2

0 1 2 3 4 5 6 7 8 9 10

**Amplification Factor**

**Amplification Factor**

**Amplification Factor**

**Amplification Factor**

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

F3-4

F3-4

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

**Figure 24.** Natural frequency of vibration for the 3rd floor.

w 1-1

w 1-1

0 1 2 3 4 5 6 7 8 9 10

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

**Figure 25.** Natural frequency of vibration of the 4thfloor (wooden).

0 1 2 3 4 5 6 7 8 9 10

F3-1

F3-1

0 1 2 3 4 5 6 7 8 9 10

**Amplification Factor**

**Amplification Factor**

**Amplification Factor**

**Amplification Factor**

**Amplification Factor**

**Amplification Factor**

Figure 25. Natural frequency of vibration of the 4thfloor (wooden).

Figure 25. Natural frequency of vibration of the 4thfloor (wooden).

**Amplification Factor**

**Amplification Factor**

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

Figure 23. Natural frequency of vibration for the 2nd floor.

**Figure 23.** Natural frequency of vibration for the 2nd floor.

Seismic Hazard Analysis for Archaeological Structures — A Case Study for EL Sakakini Palace Cairo, Egypt http://dx.doi.org/10.5772/54395 

Figure 24. Natural frequency of vibration for the 3rd floor. **Figure 24.** Natural frequency of vibration for the 3rd floor. 

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

Figure 24. Natural frequency of vibration for the 3rd floor.

0 1 2 3 4 5 6 7 8 9 10

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

Figure 25. Natural frequency of vibration of the 4thfloor (wooden). **Figure 25.** Natural frequency of vibration of the 4thfloor (wooden).

Figure 23. Natural frequency of vibration for the 2nd floor.

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

F2-4

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

F2-7

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

**Figure 23.** Natural frequency of vibration for the 2nd floor.

0 1 2 3 4 5 6 7 8 9 10

F2-1

Engineering Seismology, Geotechnical and Structural Earthquake Engineering

**Amplification Factor**

**Amplification Factor**

**Amplification Factor**

**Amplification Factor**

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

F2-5

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

F2-8

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

F2-10

0 1 2 3 4 5 6 7 8 9 10

F2-2

**Amplification Factor**

**Amplification Factor**

**Amplification Factor**

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

F2-6

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

F2-9

0 1 2 3 4 5 6 7 8 9 10 **Frequency (Hertz)**

0 1 2 3 4 5 6 7 8 9 10

F2-3

**Amplification Factor**

**Amplification Factor**

**Amplification Factor**

300m/s and a thickness of 5 to 10meters. It is a man made fill material in rather loose conditions. Below there is a clayey material with average Vs velocity equal to 400-600m/s. At -35m in average we found saturated compacted sand and gravels with Vs velocity exceeding 700m/s. It is considered as the seismic bedrock for the foreseen detailed site-specific analysis of the

Seismic Hazard Analysis for Archaeological Structures — A Case Study for EL Sakakini Palace Cairo, Egypt

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31

Based on the ambient noise campaign the fundamental frequency of the ground is of the order of 3.0 to 3.5sec very close to the fundamental frequency of the palace. Resonance phenomena should be expected and considered seriously in the detailed analysis of the structure. There are strong evidences that the upper two stories with wooden floors, which are presenting high amplification factors, are subjected to several damages and

ground response.

**Author details**

Sayed Hemeda\*

**References**

degradation of their bearing capacity.

Address all correspondence to: hemeda@civil.auth.gr

(Editor), Alsevier, Amsterdam, 141-152.

Engineering, Englewood Cliffs, New Jersey.

research institute.

Conservation Department, Faculty of Archaeology, Cairo University, Egypt

(Greece). Soil Dynamics & Earthquake Engineering, 24, 1, 49-67.

D.): Bollettinodi Geofisica Teoricaed Applicata, 21, No. 84, 245 - 310

effects in the region of Friull, Italy, J. Geophysics. Res. 101, 22355-22369.

[1] Apostolidis P., Raptakis D., Roumelioti Z., Pitilakis K., (2004), Determination of S-Wave velocity structure using microtremors and SPAC method applied inThessaloniki

[2] Ben-Menahem, A., (1979). Earthquake catalogue for the Middle East (92 B. C. - 1980 A.

[3] Castro, R. R., F. Pacor, A. Sala, and C. Petrungaro (1996). S Wave attenuation and site

[4] Celebi, M., C. Dietel, J. Prince, M. Onate, and G. Chavez (1987). Site amplification in Mexico City (determined from 19 September 1985 strong-motion records and from records of weak motion), in Ground Motion and Engineering Seismology, A. S. Cakmak

[5] Chopra, A. K. (1981). Dynamics of structures, a primer Earthquake engineering

[6] Chopra, A. K., (1995). "Dynamic of structures – Theory and Application to Earthquake

**Figure 26.** Natural frequency of vibration of the 5thfloor (wooden).

Figure 26. Natural frequency of vibration of the 5thfloor (wooden).

Table 5.Natural frequencies of vibration of El Sakakini Palace.


**Table 5.** Natural frequencies of vibration of El Sakakini Palace.

site-specific analysis of the ground response.

#### ElSakakini Palace is an important monument in Egypt. We presented the main results **6. Conclusions**

**5. CONCLUSIONS** 

characteristics of the ground response and the structure. Based on the available maximum intensity maps for historical earthquakes (>2200BC) the maximum Mercalli Intensity expected at ElSakakini Palace site is VII*.* The peak horizontal acceleration at the seismic rock basement found at -35m approximately, and for 10% probability of exceedance in 50 years is 144 cm/sec<sup>2</sup> (0.147g), while for 100 years is 186 (cm/sec2 ) (0.19 g). We determined the average soil profile using ElSakakini Palace is an important monument in Egypt. We presented the main results of the seismic hazard analysis and the geophysical campaign to estimate the main characteristics of the ground response and the structure. Based on the available maximum intensity maps for historical earthquakes (>2200BC) the maximum Mercalli Intensity expected at ElSakakini Palace site is VII.

of the seismic hazard analysis and the geophysical campaign to estimate the main

different geophysical campaigns. It is found that the upper layer has an average shear wave velocity lower than 300m/s and a thickness of 5 to 10meters. It is a man made fill material in rather loose conditions. Below there is a clayey material with average Vs velocity equal to 400-600m/s. At -35m in average we found saturated compacted sand and gravels with Vs velocity exceeding 700m/s. It is considered as the seismic bedrock for the foreseen detailed The peak horizontal acceleration at the seismic rock basement found at -35m approximately, and for 10% probability of exceedance in 50 years is 144 cm/sec2 (0.147g), while for 100 years is 186 (cm/sec2 ) (0.19 g). We determined the average soil profile using different geophysical campaigns. It is found that the upper layer has an average shear wave velocity lower than 300m/s and a thickness of 5 to 10meters. It is a man made fill material in rather loose conditions. Below there is a clayey material with average Vs velocity equal to 400-600m/s. At -35m in average we found saturated compacted sand and gravels with Vs velocity exceeding 700m/s. It is considered as the seismic bedrock for the foreseen detailed site-specific analysis of the ground response.

Based on the ambient noise campaign the fundamental frequency of the ground is of the order of 3.0 to 3.5sec very close to the fundamental frequency of the palace. Resonance phenomena should be expected and considered seriously in the detailed analysis of the structure. There are strong evidences that the upper two stories with wooden floors, which are presenting high amplification factors, are subjected to several damages and degradation of their bearing capacity.
