Mass Irrugularity
Go to Results - Structure Results – Centers of Mass & Rigidity – Copy Mass X data.
Paste the Data (yellow)
🏗️ Mass Irregularity Check in Structural Engineering Using Excel
In structural engineering, mass irregularity refers to a significant variation in mass between adjacent stories of a building. Such irregularities can adversely affect a structure's seismic performance, leading to increased vulnerability during earthquakes. Identifying and addressing mass irregularities is crucial for ensuring structural safety and compliance with building codes.
📘 Understanding Mass Irregularity
According to building codes like ASCE 7-16, mass irregularity is defined as a condition where the effective mass of any story is more than 150% of the effective mass of an adjacent story. This criterion helps in identifying significant mass discontinuities that could impact the dynamic response of structures during seismic events. (IdeCAD Help)
🧪 Performing Mass Irregularity Check Using ETABS and Excel
To assess mass irregularity:
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Model the Structure in ETABS:
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Ensure all structural elements and load cases are accurately defined.
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Run the Analysis:
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Perform the analysis to obtain mass distribution results.(Scribd)
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Extract Mass Data:
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Navigate to
Display→Show Tables→Structure Results→Centers of Mass & Rigidity. -
Copy the mass data (e.g., Mass X) for each story.
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Use Excel for Mass Irregularity Check:
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Paste the extracted mass data into a pre-formatted Excel template.
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Calculate the mass ratio between adjacent stories.
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Identify any instances where the mass of a story exceeds 150% of the mass of an adjacent story, indicating mass irregularity.(Scribd)
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📥 Download Mass Irregularity Check Excel Template
For a practical application, you can download a pre-formatted Excel template to perform mass irregularity checks:
