Arch constructions

Arch constructions

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Arch constructions

Language: English
Description: In ancient times - before steel and concrete - heavy buildings and constructions were realized using arches and vaults. The stability mechanism is that heavy weight of the construction makes the pressure force between the arch blocks really large. This in turns makes the friction force very large (recall that the friction force depends on the force an object is pressed onto a surface). The friction force becomes so large that the arch blocks can’t slide and the construction becomes stable. This lesson allows the student to experiment with arch design of bridges. As a final task the student should demonstrate that a simple car can safely travel over the bridge.
Target: Key Stage 3, Key Stage 4
Category: Exercise, Laboratory
Discipline: Friction
Learning objectives:
  • Knowledge of arch architecture and construction stability
  • Understand the material properties that are important for arch stability
  • By successive experiments test and improve their construction design to a functioning arch
In class: Let the students study some examples of ancient arch construc- tions, e.g., for supporting a roof or a bridge. Not that rocks of large dimension could not be produced or lifted. Let the students think of different designs of constructing a bridge from many small rocks using no concrete or nails. Let the students experiment with these using Algodoo. What conclusions can be drawn regarding shapes and materials of the building elements? Help the students make decisions and ask guiding questions.

Encourage the students to follow the procedure Create – Predict – Interact – evaluate.

Allow the students to follow-up and share their experiences in class after the simulation

Steps in Algodoo


Create a scene

Create a ground plane and building block elements. Experiment with different shapes and materials (mass density and friction). The sculpturing tool is great for cutting the blocks into a shape that fits.


Make a prediction

What shape and material will be important for a stable arch bridge?


Run/interact

Run the simulation and interact with it. Drive a simple vehicle over the bridge or drop a heavy load on it.
Arch.png


Evaluate

What shapes and materials were most successful? Why is that?

What is the mechanism behind the stability? Force visualization helps to understand.

Can the design be improved further? How?