MARP Parabolic Arch Unit
The Parabolic Arch Unit, "MARP", allows to study an isostatic (or statically determinate) parabolic arch (having one fixed support and one movable support) or a hyperstatic (or statically indeterminate) parabolic arch (having both supports fixed) under load, the deformations generated and the reactions of the supports of the arch.
The Parabolic Arch Unit "MARP" contains a pre-shaped articulated arch, which can be subjected to point or evenly distributed loads by means of seven uniformly distributed cables (cords) with hangers.
One support of the arch is fixed whereas the other support can be fixed or movable in horizontal direction. When both supports are fixed, the hyperstatic arch conditions will be studied (1 degree of freedom), whereas if one of the supports is movable, the isostatic arch conditions will be analyzed (0 degrees of freedom).
To fix the movable support, so that it works as a fixed support, a set of weights is used to cancel out the horizontal displacement and another set of weights to balance the vertical reaction of the support.
To measure the deformation of the arch under load the unit has two dial gauges, one that measures the horizontal displacement of the free support and another that measures the bending of the arch.
Exercises and guided practices
GUIDED PRACTICAL EXERCISES INCLUDED IN THE MANUAL
- Study of the mechanical principles of a parabolic arch.
- Differences between an isostatic arch and a hyperstatic arch.
- Analysis of the arch under load: Measurement of the deformations. Measurement of the reactions of the supports in the hyperstatic arch.
- Influence of a point load or an evenly distributed load on the reactions at the support and on the deformation of the arch.
- Evaluation of the relation between applied load and horizontal displacement.
- Comparison of the horizontal displacement with theoretical values.
- Analysis of the horizontal thrust.