Forms and Characteristics of Truss Structural Steel Pipe

Truss structural steel pipe is the important one kind of steel structure, it is a truss structure in the form of a structure composed of steel pipe materials, also known as the steel girder structure, pipe truss and structure, etc. Due to the stronger adaptability, in recent years has been widely used in large-span spatial structure. Pipe truss structure system of plane or space truss structure, and the difference between general truss connecting nodes in a different way: space truss structure with bolt ball or hollow node. Roof truss of the past are often USES plate type node, and pipe truss structure in the node using the direct welding rods are node (or nodes). In the nozzle-vessel junction node, only on the same axis by two executives. The rest of the bar (branch) by the curve ends after processing, direct welding in linking bar (the head) not well versed in the appearance of bar in the node area may have certain gap (gap type node), may also overlap (overlapping nodes). Nozzle-vessel junction wire-cutting manufacturing process has been seen as more difficult. Because intersection in the number of steel pipe, Angle and size of the curve has different forms, and groove processing difficult. But with the development of multi-dimensional numerical control cutting technology. These difficulties have been overcome. At present domestic some enterprise equipped with the technology, pipe truss structure are nodes in the application of the construction of large span unprecedented.

(1) the classification of pipe truss. According to the mechanical characteristics and layout of the bar is different, can be divided into flat pipe truss structure and spatial truss structure. Plane of top chord and bottom chord of pipe truss structure and CHS in the same plane, out-of-plane stiffness is poorer. General need through the lateral support guarantee the lateral stability of the structure. In existing tube truss structure engineering, with Warren truss and Pratt truss forms, Warren truss is generally the most economical arrangement, compared with Pratt truss Warren truss only half its number of CHS and node, and diagonal cutting length is unified, which can greatly save material and processing time. Vierendeel truss is mainly used in building, function or use of the function is not allow to support the diagonal of the situation, spatial pipe truss structure is usually triangular cross section, compared with the planar truss structure, it can has a large span, good stability, and triangle truss torsional rigidity is big and beautiful. Decorate in the don't or can't decorated surface outside support, triangle truss can provide larger span space. A set of triangle truss is similar to a space rigid frame structure, and more economical. Can reduce the lateral support components and improve the lateral stability and torsional rigidity. For small span structure, can not decorate lateral support.

(2) the cross-section form of fittings. Commonly used form of bar section for circle, rectangle, square, etc. Line connection components of different cross section can be divided into the following several kinds of truss forms: C: C type truss chord and are circular tube are CHS truss structure; R - R type truss: namely, chord and CHS are square steel tube or rectangular tubes are of truss structures; R - c type truss: rectangular section chord with circular cross section direct penetration welding of CHS truss structure.

(3) the advantages of pipe truss. With the development of large public buildings, more and more high to the requirement of structure and span of space, space steel truss with the stable properties and good bearing has been widely used. Spatial mild steel pipe truss structure form in accordance with the truss section form can be divided into triangular space truss, quadrilateral space truss, polygonal space truss and variable cross-section space truss, etc. Steel structure because of its beautiful appearance, reasonable mechanical characteristics and superior economy, in the modern industrial workshop, warehouse, gymnasium, exhibition hall, the venue, terminal, railway stations and office buildings, commerce-residence building, hotel, etc has been widely used in construction.