ABSTRACT
Today many innovative constructive systems use the principle of prestress applied for many materials according to identical mechanical principles. The utilization of prestress depends on characteristics of used materials. Conceptual design of structure means the invention of an engineering structure which optimally satisfies the form-force-material relationship. Hybrid systems are possible to construct in different geometrical forms, on which affects: the number and schedule of struts, flow of tension in cable, or shape and position of the cable in contrast to girder and girder’s cross section. When choosing a hybrids’ constellation, all listed parameters may vary geometrically, which has implications for the behavior of system in carrying the load, by directly affecting the change in stiffness of the system. Besides geometrical parameters, the stiffness of the hybrid system is also influenced by variations of materials’ properties and their relationships. Pre-stressing of the hybrid systems is one of the ways of increasing the whole system’s stiffness. This paper presents the theoretical and experimental research on behavior of the timber-steel hybrid girders’ different geometrical constellation with external prestressing and in different conditions of timber moisture.
