This simple Python software is designed to assist Civil and Geotechnical Engineers in performing site-specific seismic hazard assessments. The program calculates the seismic response spectrum based on user-provided geotechnical and seismic parameters, generating a comprehensive technical report that includes the response spectrum data and figures. The analysis adheres to Eurocode 8 and the Greek Annex, ensuring compliance with international standards for earthquake-resistant design.

1. Seismic Hazard Assessment Software in Python
by Prof. Dr. Costas Sachpazis, May 2024
Overview
This simple Python software is designed to assist Civil and Geotechnical
Engineers in performing site-specific seismic hazard assessments. The
program calculates the seismic response spectrum based on user-provided
geotechnical and seismic parameters, generating a comprehensive technical
report that includes the response spectrum data and figures. The analysis
adheres to Eurocode 8 and the Greek Annex, ensuring compliance with
international standards for earthquake-resistant design.
Note: “dejavu-sans” Fonts must be installed in your PC

2. Functions and Usage
1. get_user_inputs()
o Description: This function prompts the user to input site-
specific parameters necessary for the seismic hazard
assessment.
o Parameters Collected:
 Site Class: The soil classification at the site (A, B, C, D, E).
 Seismic Zone Factor (ag): The reference peak ground
acceleration for the seismic zone.
 Importance Factor (γI): The importance factor of the
structure.
o Usage: The user runs the program and inputs the requested
parameters when prompted.
2. get_site_amplification_factor(site_class)
o Description: This function determines the site amplification
factor (S) based on the site class provided by the user.
o Parameters:
 site_class: The soil classification at the site.
o Returns: The site amplification factor (S).
o Usage: Automatically called by the main program to obtain the
amplification factor for the given site class.
3. generate_response_spectrum(ag, S, gamma_I)
o Description: This function generates the response spectrum
data based on the input parameters.
o Parameters:

3.  ag: The seismic zone factor (reference peak ground
acceleration).
 S: The site amplification factor.
 gamma_I: The importance factor of the structure.
o Returns: Arrays of periods (T) and spectral accelerations (Sa).
o Usage: Automatically called by the main program to compute
the response spectrum.
4. create_technical_report(site_class, ag, gamma_I, T, Sa, fig_path)
o Description: This function generates the technical report in PDF
format, including the response spectrum data and figures.
o Parameters:
 site_class: The soil classification at the site.
 ag: The seismic zone factor.
 gamma_I: The importance factor of the structure.
 T: Array of periods.
 Sa: Array of spectral accelerations.
 fig_path: File path to the saved response spectrum figure.
o Usage: Automatically called by the main program to generate
and save the PDF report.
5. main()
o Description: This is the main function that orchestrates the
program execution. It calls the other functions to collect inputs,
compute the response spectrum, and generate the technical
report.

4. o Usage: Run the program to start the process. The user will be
prompted to enter the required parameters, and the program
will handle the rest.
Usage for Civil Engineers
Civil Engineers can use this software to perform detailed seismic hazard
assessments for their projects. By inputting site-specific geotechnical and
seismic parameters, the software calculates the seismic response spectrum,
which is crucial for designing earthquake-resistant structures. The generated
technical report includes comprehensive data and visualizations, aiding in
the analysis and decision-making process.
Compliance with Eurocode 8
This software performs its analysis in accordance with Eurocode 8: Design of
structures for earthquake resistance and the Greek National Annex to
Eurocode 8. These standards provide guidelines and specifications for
assessing seismic hazards and designing structures to withstand seismic
events. By adhering to these codes, the software ensures that the analysis
meets international standards for safety and reliability.
Example of Usage
1. Run the Program: Execute the Python script in your Python
environment.
2. Input Parameters: When prompted, enter the site class, seismic zone
factor, and importance factor.
3. Generate Report: The program calculates the seismic response
spectrum and generates a PDF report containing the analysis results
and figures.

5. 4. Review Report: Open and review the generated PDF report to
understand the seismic hazard assessment for your site.
Summary
This Seismic Hazard Assessment Software developed by Prof. Dr. Costas
Sachpazis is a powerful tool for Civil Engineers, providing a streamlined
process for performing site-specific seismic hazard assessments. By following
Eurocode 8 and the Greek Annex, the software ensures that the analysis is
accurate and compliant with international standards, facilitating the design
of earthquake-resistant structures.
Should you need any clarifications and/or explanations, please contact me at
costas@sachpazis.info
Dr. Costas Sachpazis

6. Python Script/Code:
********************** START
import matplotlib.pyplot as plt
import numpy as np
from fpdf import FPDF, XPos, YPos
# Define a custom PDF class to use a Unicode font
class PDF(FPDF):
def header(self):
self.set_font("DejaVu-Bold", size=16)
self.cell(200, 10, text="Seismic Hazard Assessment Report",
new_x=XPos.LMARGIN, new_y=YPos.NEXT)
self.ln(10)
self.set_font("DejaVu-Bold", size=12)
self.cell(200, 10, text="Python Program/Code written by Professor Dr.
Costas Sachpazis, Civil Engineer", new_x=XPos.LMARGIN,
new_y=YPos.NEXT)
self.ln(20)
# Function to get user inputs
def get_user_inputs():
site_class = input("Enter site class (A, B, C, D, E): ").strip().upper()
seismic_zone = float(input("Enter seismic zone factor (ag): "))
importance_factor = float(input("Enter importance factor (γI): "))

7. return site_class, seismic_zone, importance_factor
# Function to determine site amplification factor S
def get_site_amplification_factor(site_class):
site_factors = {
'A': 1.0,
'B': 1.2,
'C': 1.15,
'D': 1.35,
'E': 1.4
}
return site_factors.get(site_class, 1.0)
# Function to generate the response spectrum
def generate_response_spectrum(ag, S, gamma_I):
TB = 0.15
TC = 0.5
TD = 2.0
T = np.linspace(0, 3, 300)
S_eff = ag * S * gamma_I
Sa = np.piecewise(T,

8. [T < TB, (T >= TB) & (T < TC), (T >= TC) & (T < TD), T >= TD],
[lambda T: S_eff * (1 + T / TB),
lambda T: S_eff,
lambda T: S_eff * TC / T,
lambda T: S_eff * TC * TD / (T ** 2)])
return T, Sa
# Function to create the technical report
def create_technical_report(site_class, ag, gamma_I, T, Sa, fig_path):
pdf = PDF()
# Add the Unicode font
pdf.add_font("DejaVu", "", "DejaVuSans.ttf")
pdf.add_font("DejaVu-Bold", "", "DejaVuSans-Bold.ttf")
pdf.set_font("DejaVu", size=12)
pdf.add_page()
pdf.cell(200, 10, text=f"Site Class: {site_class}", new_x=XPos.LMARGIN,
new_y=YPos.NEXT)
pdf.cell(200, 10, text=f"Seismic Zone Factor (ag): {ag}",
new_x=XPos.LMARGIN, new_y=YPos.NEXT)

9. pdf.cell(200, 10, text=f"Importance Factor (γI): {gamma_I}",
new_x=XPos.LMARGIN, new_y=YPos.NEXT)
pdf.ln(10)
pdf.cell(200, 10, text="Response Spectrum Data:", new_x=XPos.LMARGIN,
new_y=YPos.NEXT)
pdf.ln(10)
for t, sa in zip(T, Sa):
pdf.cell(200, 10, text=f"T = {t:.2f}, Sa = {sa:.4f}", new_x=XPos.LMARGIN,
new_y=YPos.NEXT)
pdf.add_page()
pdf.cell(200, 10, text="Response Spectrum Figure:",
new_x=XPos.LMARGIN, new_y=YPos.NEXT)
pdf.ln(10)
pdf.image(fig_path, x=10, y=None, w=190) # Adjust x, y, w as needed
pdf.output("Seismic_Hazard_Assessment_Report.pdf")
# Main program
def main():
site_class, ag, gamma_I = get_user_inputs()
S = get_site_amplification_factor(site_class)

10. T, Sa = generate_response_spectrum(ag, S, gamma_I)
# Plot the response spectrum
plt.figure()
plt.plot(T, Sa, label='Response Spectrum')
plt.xlabel('Period (T)')
plt.ylabel('Spectral Acceleration (Sa)')
plt.title('Elastic Response Spectrum')
plt.legend()
plt.grid(True)
fig_path = "response_spectrum.png"
plt.savefig(fig_path)
plt.show()
# Generate the technical report
create_technical_report(site_class, ag, gamma_I, T, Sa, fig_path)
print("Seismic Hazard Assessment Report generated successfully.")
if __name__ == "__main__":
main()
********************** END