Running an EQ Simulation in EE-UQ: how a 5-story RC building responds to earthquakes

Awesome! Let’s go step by step through running a simulation in EE-UQ to analyze how a 5-story reinforced concrete building responds to earthquakes. If you're more interested in quoFEM, let me know, and I can guide you through an optimization example instead.

📌 Step-by-Step Guide: Running an Earthquake Simulation in EE-UQ

🎯 Goal:

Simulate the seismic response of a 5-story reinforced concrete building, considering uncertainty in material properties and ground motion variability.

🛠 Tools Needed:

• EE-UQ (Download from the NHERI SimCenter)

• A finite element model (FEM) of a 5-story building (created in OpenSees, OpenSeesPy, or another supported tool)

• A set of earthquake ground motions (can be downloaded from PEER NGA-West2)

📌 Step 1: Open EE-UQ and Define the Structural Model

1. Launch EE-UQ on your computer.

2. In the "GI" (General Information) tab, enter:

   • Project title (e.g., "5-Story RC Building Seismic Analysis").

   • Author name and units (e.g., SI or Imperial).

3. Go to the "SIM" (Structural Model) tab and select the model type:

   • If you have an OpenSees model:

     • Choose "OpenSees" as the FEM engine.

     • Upload your .tcl file (if using OpenSees) or .py file (if using OpenSeesPy).

   • If you want to use a predefined model, select a "Simple Model" and define building properties (height, number of floors, stiffness, damping, etc.).

📌 Step 2: Define Earthquake Ground Motions

1. Go to the "EVT" (Event) tab to specify the seismic input.

2. Choose how to define earthquakes:

   • Use recorded earthquakes: Import ground motion records from a database like PEER NGA-West2.

   • Generate synthetic earthquakes: Define earthquake parameters like magnitude, fault distance, and soil type to generate artificial ground motion.

3. If using real ground motions, upload multiple records (e.g., 10 different earthquakes) to account for uncertainty.

📌 Step 3: Define Uncertainty in Material Properties

1. Go to the "RV" (Random Variables) tab to introduce uncertainty.

2. Define random variables for uncertain properties:

   • Concrete compressive strength (e.g., normally distributed with a mean of 4000 psi and standard deviation of 500 psi).

   • Steel yield strength (e.g., mean of 60 ksi, standard deviation of 5 ksi).

   • Damping ratio (e.g., 5% ± 1%).

3. EE-UQ will sample different values from these distributions during the simulation.

📌 Step 4: Select Analysis Method

1. Go to the "UQ" (Uncertainty Quantification) tab to choose the simulation method.

2. Select one of the following:

   • Monte Carlo Simulation (MCS): Runs the model multiple times with different random inputs.

   • Latin Hypercube Sampling (LHS): A more efficient way to explore uncertainty with fewer simulations.

3. Set the number of samples (e.g., 100 simulations).

📌 Step 5: Run the Analysis

1. Click the "RUN" button to start the simulation.

2. EE-UQ will:

   • Apply different earthquake records.

   • Modify material properties based on uncertainty.

   • Compute structural response for each case.

📌 Step 6: View & Interpret Results

1. Go to the "RES" (Results) tab to analyze output.

2. Key results include:

   • Maximum roof displacement (shows how much the building sways).

   • Story drift ratios (important for checking if the building meets seismic codes).

   • Base shear forces (helps in foundation design).

   • Distribution of responses (visualizing uncertainty).

3. Use these results to determine if the building is safe or needs retrofits.

📌 Next Steps

• If the story drifts exceed code limits, consider adding dampers or increasing stiffness.

• If the variability in response is too high, try reducing material uncertainty by improving construction quality.

• If the building performs well, use these results to justify its seismic resilience.

🚀 Summary of Key Actions

Step	Action
Step 1	Load or create the structural model in OpenSees/OpenSeesPy
Step 2	Import or define earthquake ground motions
Step 3	Set material property uncertainties (concrete, steel, damping)
Step 4	Choose uncertainty quantification method (Monte Carlo, LHS)
Step 5	Run the analysis
Step 6	Analyze results (displacement, drift, base shear)

🌟 Want to Try quoFEM Instead?

If you're more interested in optimizing a beam design or calibrating an FE model, I can walk you through a similar step-by-step guide using quoFEM. Let me know what works best for you! 🚀

of course i do!