Moving Aspects of Structures

Abstract

In the present paper moving aspects of structures are taken up. In our daily structural design the structures are assumed to be immovable, and most of structural calculations are car ried out on the basis of static principles. Although we know that a structure always produces such a movement due to loading that is referred to as deformation or displacement, its magnitude is normally too small to be signifcant incomparison with the dimensions of the structure, and its effect on the structural behaviors is neglected, the whole phenome non being treated as static. There are cases, however, wherelarge movements are actually experienced by our structures due to different reasons. Many of them are due to excessive loading and unexpected instability, often leading to collapse of the structures. Some other cases are related to vibration where resonance of structures with external agencies such as earthquakes and wind is a key question. Self excited oscillation sometimes produces catastrophic and very spectacular motion of structures. Controlled motions can be obtained by adopting isolators to cope with the effects of earthquakes. Dampers which are often incorporated in seismic isolation systems are normally rather still, but motion of tuned mass dampers is sometimes very signifcant. Structures can be designed to be assembled on the ground and then hoisted to the position. In erection of such structures a big movement is observed as in Pantadome System. Finally those structures which are originally intended to move are described with examples of rocking stones and a flying carp.

Keywords