Pratt trusses are commonly used in long span buildings ranging from 20 to 100 m in span. Some of the commonly used types are shown below. Each can vary in overall geometry and in the choice of the individual elements. A wide range of truss forms can be created. Under gravity loads, the top and bottom chords of the truss provide the compression and tension resistance to overall bending, and the bracing resists the shear forces. Trusses comprise assemblies of tension and compression elements. Longitudinal stability is also provided by a wind girder in the roof and vertical bracing in the elevations. Bracing in both directions is necessary at the top level of the simple structure it is achieved by means of a longitudinal wind girder which carries the transverse forces due to wind on the side walls to the vertical bracing in the gable walls. In the second case, (right) each truss and the two columns between which it spans, constitute a simple structure the connection between the truss and a column does not resist the global bending moment, and the two column bases are pinned. Loads are applied to the portal structure by purlins and side rails. In the first case (left) the lateral stability of the structure is provided by a series of portal trusses the connections between the truss and the columns provide resistance to a global bending moment. Longitudinal stability provided by transverse wind girder and vertical bracings (green) Lateral stability provided by longitudinal wind girder and vertical bracings in the gables (blue) Longitudinal stability provided by transverse wind girder and vertical cross bracings (blue) Lateral stability provided by portal trusses. Two types of general arrangement of the structure of a typical single storey building are shown in the figure below. This article focuses on typical single storey industrial buildings, where trusses are widely used to serve two main functions: Trusses are also used to carry heavy loads and are sometimes used as transfer structures. Trusses are used in a broad range of buildings, mainly where there is a requirement for very long spans, such as in airport terminals, aircraft hangers, sports stadia roofs, auditoriums and other leisure buildings. Overview of trusses Use of trusses in buildings
0 kommentar(er)
