Program MY1a – MS EC8 NA response spectrum generator (Imai-Tonouchi All Soil)

QUAKE ADVICE_Seismic Elastic Response Spectrum Report

Determination of Seismic Elastic Response Spectrum Based on Imai & Tonouchi All Soil Model

1. Input Parameters:

'Imai & Tonouchi All Soil Model' requires information of the thickness, and SPT-N for soil layers in each Borehole.

I. Location of Site:
II. Importance Class of Structure:
III. PGA on rock (g):

IV. Thickness and SPT-N Values of each Borehole:

Note:

D1, D2 ..D20 refer to column nos. 1-20 for inputting the thicknesses (m) of the soil layers whereas N1, N2 ..N20 refer to the input of the SPT-N (blows/300 mm) values.
Table can be filled manually or by performing copy (CTRL+C) and paste (CTRL+V) of data from Excel spreadsheet.
If all entries to a particular “thickness” column have been left blank, the program will automatically fill in a default thickness of 1.5 m.
SPT-N values that have been taken from the testing of very stiff materials have to be corrected to the penetration depth of 300 mm. For example, an SPT-N value of 50 for the penetration depth of 100 mm should be corrected to 150.
Avoid including too many borelogs from too closely spaced boreholes into one analysis as doing this would not necessarily result in obtaining an accurate estimate of the site period. The Malaysian EC8 NA recommends that the spacing of boreholes to be included into site classification analyses be spaced at 15 m - 45 m.
Must also avoid including borelogs taken from a very large area featuring systematic spatial variation in geology within the area. The maximum number of borelogs to be included into one analysis is capped at 20.

SPT-N Values and Soil Description (BG Look, 2014)
Very Loose	0-4	Very Soft	0-2
Loose	4-10	Soft	2-5
Medium	10-30	Firm	5-10
Dense	30-50	Stiff	10-20
Very Dense	>50	Very Stiff	20-40
-	-	Hard	>40

	Borehole 1		Borehole 2		Borehole 3		Borehole 4		Borehole 5		Borehole 6		Borehole 7		Borehole 8		Borehole 9		Borehole 10		Borehole 11		Borehole 12		Borehole 13		Borehole 14		Borehole 15		Borehole 16		Borehole 17		Borehole 18		Borehole 19		Borehole 20
	D1	N1	D2	N2	D3	N3	D4	N4	D5	N5	D6	N6	D7	N7	D8	N8	D9	N9	D10	N10	D11	N11	D12	N12	D13	N13	D14	N14	D15	N15	D16	N16	D17	N17	D18	N18	D19	N19	D20	N20
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V. Energy Ratio (N₆₀/N_measured):

Note: Energy ratio is the conversion factor for converting the measured N values to corrected N values corresponding to 60% energy efficiency. A value of 1 is suggested for the case of Malaysia (Sabatini et al., 2002).

2. Results: Soil Characteristics and Elastic Response Spectrum

I. Soil Profile with SPT-N Value:

Figure 1: SPT-N Profile

II. Average Shear Wave Velocity (V_s) and Natural Time Period (T_s) of Soil:

- Imai & Tonouchi all soil model is used to calculate the average shear wave velocity. $$ {V_s = \frac{H_s}{ \sum^n_{i=1} \dfrac{d_i}{93.7 \times N_{60}^{0.31}} }}\tag{1}$$ $$ {T_s = \frac{4 \times H_s}{V_s}}\tag{2}$$ Where:
H_s = total depth of soil,
n = number of soil layers,
d_i = thickness of soil layer 'i',
N_{60_i} = corrected SPT-N value (corresponding to 60% energy efficiency) of soil layer 'i'

Borehole No.	Average Shear Wave Velocity (m/sec)	Site Period (sec)

III. Seismic Elastic Response Spectrum:

a. Response Spectral Acceleration (RSA) Diagram:

Figure 2: RSA Diagram

b. Acceleration Displacement Response Spectrum (ADRS) Diagram:

Figure 3: ADRS Diagram

T (sec)	RSA-soil_without β (g)	RSD-soil_without β (mm)	RSA-soil_with β (g)	RSD-soil_with β (mm)

3. References:

Department of Standards Malaysia (2017). MS EN 1998-1:2015 Malaysia National Annex to Eurocode 8: Design of structures for earthquake resitance – Part 1: General rules, seismic actions and rules for buildings.

European Commitee for Standardization (2004). EN 1998-1:2004 Eurocode 8: Design of structures for earthquake resistance - Part 1 : General rules, seismic actions and rules for buildings.

Look, B. G. (2014). Handbook of geotechnical investigation and design tables. CRC Press.

Sabatini, P.J., Bachus, R. C., Mayne, P. W., Schneider, James A., Zettler, T. E. (2002). Geotechnical Engineering Circular No. 5: Evaluation of Soil and Rock Properties, Report no: FHWA IF-02-034. Federal Highway Administration, Washington, DC United States.

Wair, B. R., DeJong, J. T., & Shantz, T. (2012). Guidelines for estimation of shear wave velocity profiles. Pacific Earthquake Engineering Research Center.

Disclaimer

The authors assume no responsibility for any injury, damage, liability, negligence and/or otherwise to any individual or property from the use or application of any of the methods, products, instructions, or ideas contained in the material herein.

SPT-N Values and Soil Description (BG Look, 2014)
Sand		Clay
Description	SPT-N Value (blows/300 mm)	Description	SPT-N Value (blows/300 mm)
Very Loose	0-4	Very Soft	0-2
Loose	4-10	Soft	2-5
Medium	10-30	Firm	5-10
Dense	30-50	Stiff	10-20
Very Dense	>50	Very Stiff	20-40
-	-	Hard	>40

	Borehole 1		Borehole 2		Borehole 3		Borehole 4		Borehole 5		Borehole 6		Borehole 7		Borehole 8		Borehole 9		Borehole 10		Borehole 11		Borehole 12		Borehole 13		Borehole 14		Borehole 15		Borehole 16		Borehole 17		Borehole 18		Borehole 19		Borehole 20
	D1	N1	D2	N2	D3	N3	D4	N4	D5	N5	D6	N6	D7	N7	D8	N8	D9	N9	D10	N10	D11	N11	D12	N12	D13	N13	D14	N14	D15	N15	D16	N16	D17	N17	D18	N18	D19	N19	D20	N20
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	Borehole 1		Borehole 2		Borehole 3		Borehole 4		Borehole 5		Borehole 6		Borehole 7		Borehole 8		Borehole 9		Borehole 10		Borehole 11		Borehole 12		Borehole 13		Borehole 14		Borehole 15		Borehole 16		Borehole 17		Borehole 18		Borehole 19		Borehole 20
	D1	N1	D2	N2	D3	N3	D4	N4	D5	N5	D6	N6	D7	N7	D8	N8	D9	N9	D10	N10	D11	N11	D12	N12	D13	N13	D14	N14	D15	N15	D16	N16	D17	N17	D18	N18	D19	N19	D20	N20
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QUAKE-ADVICE

Program MY1a – MS EC8 NA response spectrum generator (Imai-Tonouchi All Soil)

	Borehole 1		Borehole 2		Borehole 3		Borehole 4		Borehole 5		Borehole 6		Borehole 7		Borehole 8		Borehole 9		Borehole 10		Borehole 11		Borehole 12		Borehole 13		Borehole 14		Borehole 15		Borehole 16		Borehole 17		Borehole 18		Borehole 19		Borehole 20
	D1	N1	D2	N2	D3	N3	D4	N4	D5	N5	D6	N6	D7	N7	D8	N8	D9	N9	D10	N10	D11	N11	D12	N12	D13	N13	D14	N14	D15	N15	D16	N16	D17	N17	D18	N18	D19	N19	D20	N20
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