18.6 - Modal Mass and Modal Contribution
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Practice Questions
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What does modal mass represent?
💡 Hint: Think about which mass is involved in the structure's response.
Define modal contribution.
💡 Hint: Consider how modes influence seismic events.
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Interactive Quizzes
Quick quizzes to reinforce your learning
What does modal mass signify in structural dynamics?
💡 Hint: Connect it back to modes of vibration.
True or False: The modal contribution is irrelevant for low-rise structures.
💡 Hint: Reflect on the importance of all structures during dynamic analysis.
1 more question available
Challenge Problems
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Given a structure with varying modal contributions: Mode 1 contributes 40%, Mode 2 contributes 30%, and Mode 3 contributes 25%. Compute the total contribution and discuss implications for engineering assessments.
💡 Hint: Add the contributions to find the total.
In an analysis, a structure with a total of 5000 kg mass exhibits a modal mass of 4600 kg in the first three modes. What percentage of the total mass does this represent? Discuss the significance in designing for seismic responses.
💡 Hint: Use the formula: (modal mass / total mass) * 100.
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