building structures in which the main elements that support the load (wires, cables, chains, grids, sheet diaphragms, and so on) are subject only to forces of extension. Suspension structures, which exist under conditions of extension, make possible the full use of the mechanical properties of high-strength materials (for example, steel wire or kapron filaments); their light weight makes it possible to cover structures that have extremely large spans.
Suspension structures are comparatively simple to erect; they are dependable and are distinguished by architectural expressiveness. Their shortcomings include the presence of thrusts and high susceptibility to deformation under local stresses. Anchor foundations or so-called contour structures (rings that form a belt around the perimeter of the structure) are used to absorb the thrusts. The susceptibility of such structures to deformation may be reduced by introducing stabilizing elements—such as guy wires, cross stays, stiffening beams, or additional booms—as well as by giving the structure a form that permits prestressing. Geometrically invariable suspension structures made from rectilinear elements (guys) are called guy structures.
Suspension structures may be either plane or spatial. The simplest form of plane structure is a wire fastened to supports and from which are suspended elements that take the local stress. Modern plane suspension structures are used mainly in bridges and roofs, ropeways, and overpasses for pipelines.
Spatial suspension structures are generally used for large-span roofs of public and industrial buildings. Suspension roofs were first proposed and constructed by V. G. Shukhov in 1896 during the construction of the pavilions for the Nizhny Novgorod Fair, one of which was the central building of the engineering and construction pavilion, built on a circular foundation with a diameter of 68 m. Outside Russia, the development of modern suspension structures for roofs began in the 1930’s. They became widespread after World War II.
Spatial suspension structures are exceedingly varied and are distinguished by the means used to increase their stability and strength, as well as by the features of their structural design (single-boom, double-boom, and saddle types).
Single-boom suspension roofs are systems of parallel wires, a grid, or diaphragms that form cylindrical or paraboloid surfaces. The cross load is usually transmitted to the supporting elements by decking. The stiffness of the structure is increased by increasing the weight of the decking or by making it in one piece, by making the system into a suspension envelope, or—when using light decking—by the introduction of guy wires. Double-boom coverings are prestressed systems consisting of rectilinear booms whose convex sides face in opposite directions.
Saddle-type suspension roofs usually consist of systems of intersecting concave and convex wires that form either a grid or an envelope in the form of a hyperbolic paraboloid. The. majority of such structures are prestressed. A major step in the development of suspension structures was the construction in 1953 in the USA (North Carolina) of a roller skating rink with a saddle-type suspension roof according to the plans of the architect M. Nowicki.
Suspension structures, which are usually erected without scaffolding (light lifting mechanisms are used), make possible a reduction in construction costs and time; this makes them a promising form, since they can respond to the growing demand for buildings and structures with large spans.
REFERENCESSobotka, Z. Visiachie pokrytiia. Moscow, 1964. (Translated from Czech.)
Kosenko, I. S. Visiachie konstruktsii pokrytii. Moscow, 1966.
Dmitriev, L. G., and A. V. Kasilov. Vantovye pokrytiia. Kiev, 1968.
Kachurin, V. K. Staticheskii raschet vantovykh sistem. Moscow-Leningrad, 1969.
N. S. MOSKALEV