Parabolic arches are popular elements in construction engineering. They can be employed as bridges or beams for example. Normally these bridges are statically indeterminate. The special feature of the parabolic arch is that in the arch only normal forces and bending moments occur, but no shear forces. That is the case when the arch is subjected to a uniform line load and both ends are mounted in fixed supports. This enables arches to be constructed from loosely set stones – a construction technique which has been in existence for many centuries. Loads acting upon the inner of the arch are primarily compressive forces in the direction of the normal force at every point of the arch.
SE 110.16 includes a pre-shaped parabolic arch. It can be subjected to point or line loads. It is possible to suspend an elastic roadway and load it.
One of the arch’s bearings is fixed, the other is horizontally movable bearing. Weights are used to undo this movement. The floating bearing thus becomes a fixed bearing. Additional weights compensate for the vertical bearing reaction.
Dial gauges record the deflection of the arch under load and the horizontal displacement of the floating bearings. As long as the floating bearing is movable, the arch is statically determinate, though it is substantially deformed under load. As soon as the floating bearing becomes immovable, the arch is no longer statically determinate and is deformed only to a minor degree.
All the component elements of the experiment are clearly laid-out and housed securely in a storage system. The complete experimental setup is arranged in the frame SE 112.
