An earthquake-resistant building design project lets students test how structures respond when the ground moves. A shake-table model makes the invisible forces of an earthquake easier to see, measure, and improve. Students can compare towers of different heights and designs, then use evidence to decide which features work best.
This project connects physics, engineering, data analysis, and real-world safety.
Key Facts
- Earthquake shaking causes acceleration, so a building experiences inertial force: F = ma.
- Taller buildings usually sway more because the top is farther from the base and can have larger displacement.
- Diagonal bracing helps resist sideways deformation by turning rectangles into stronger triangles.
- Base isolators reduce the motion transferred from the ground to the building by allowing controlled movement at the base.
- A mass damper can reduce sway when its motion opposes the motion of the building.
- Survival time, maximum sway, and damage score are measurable outcomes for comparing designs.
Vocabulary
- Shake table
- A shake table is a platform that moves back and forth to model earthquake ground motion.
- Inertia
- Inertia is the tendency of an object to resist changes in its motion.
- Base isolator
- A base isolator is a flexible support that reduces the shaking transferred from the ground to a structure.
- Diagonal bracing
- Diagonal bracing is a structural support pattern that uses angled members to reduce sideways bending.
- Mass damper
- A mass damper is a moving weight added to a structure to absorb energy and reduce swaying.
Common Mistakes to Avoid
- Changing multiple variables at once, such as height and bracing, makes the test unfair because you cannot tell which change caused the result.
- Measuring only whether the tower falls misses useful data because sway distance, survival time, and damage level show performance differences before failure.
- Building a very rigid tower with no flexibility can be a problem because real earthquake-resistant structures often need to bend without breaking.
- Placing too much mass high on the tower increases top-heavy motion because a higher center of mass can create larger tipping effects.
Practice Questions
- 1 A model tower has a mass of 0.80 kg. During a shake-table test, it experiences a horizontal acceleration of 3.0 m/s^2. What inertial force acts on the tower?
- 2 A plain tower survives 12 s, a braced tower survives 30 s, and a base-isolated tower survives 45 s. How many times longer does the base-isolated tower survive than the plain tower?
- 3 Two towers have the same height and mass. One uses diagonal bracing and the other has only vertical and horizontal members. Explain which tower should resist sideways shaking better and why.