Structures - Two and Three Pinned Arch

This kit allows students to apply concentrated loads or uniformly distributed load (UDL) on the two-pinned circular arch and three-pinned circular arch to explore the horizontal thrust and vertical reaction forces.

This kit allows the students to swap between two-pinned circular arch and three-pinned circular arch easily by placing the corresponding arch on the dedicated places for the arch. There is also a twisting mechanism appeared on the left-hand side of the arch support block so that user can adjust the contact point with the arch.

There are 3 load cells connected to each of the 3 LCD displays (2 of the 3 load cells are used to measure the vertical reaction forces of the arch while 1 of the 3 load cells is used to measure the horizontal reaction forces of the arch).

There are different loading scenarios that student can setup for doing the experiments. For example, student can move the concentrated load across the span of the arch and measure the corresponding forces. In this case, by plotting the graph, students can explore that the horizontal forces for the two types of arches have different shapes. Students can also apply UDL for half-span or full span on the arch. This allows students to calculate the theoretical reaction forces and compare these values with the experimental values. This will reinforce their knowledge in principle of moments, principle of superposition, and equilibrium equations.

Construction is made in 2mm mild steel, providing a strong and stiff base to perform experiments on.

Learning Objectives

• Horizontal Thrust and Vertical Reaction Forces when:

           -          the position of concentrated load is varying.

           -          the type of loads is different (UDL & concentrated load)

           -          two-pinned circular arch is used.

- three-pinned circular arch is used.

• Principle of Moments.
• Principle of Superposition.
• Equilibrium Equations.
• Comparison of theoretical forces vs experimental forces.