SU708035A1 - Method of prestraining long metal elements - Google Patents

Description

I

The invention relates to the field of construction and can be used mainly in the construction of metal frames of industrial buildings, performed, in particular, from elements of an I-beam or box-section.

Nowadays, in the industrial construction, the creation of the initial stress state has become widespread with the help of additional details such as cables, cables, cables, bunches of high-strength corrugated fibers, etc.

A known method of prestressing a metal beam, for example, a two-section cross-section, in the process of its preparation, consists in the fact that the wall of the beam is elastically deformed along the longitudinal axis and fixed in such a STATE, then the wall is rigidly fixed to beams himself.

The closest solution is a method of prestressing metal long I-beam elements by stretching the walls of the element, following the fixation of the walls in the deformed state and rigid fixation to them according to 2.

The disadvantage of the above methods of pre-limiting voltage is that, as they do not allow, to create a uniformly distributed support of pre-stress in long elements of varying height, which are widely used. in the frames of single-storey industrial buildings.

The use of frame with a variable section height in frame structures allows to significantly reduce the consumption of materials, and creating a uniformly distributed pre-tensioning support in the walls of such columns will make them thin-walled and thereby obtain additional savings.

Claims (2)

The purpose of the invention is to ensure uniform stretching of the walls of the elements of variable height. It is achieved by the fact that, in the implementation of the method of prestressing metal long elements of an I-section by stretching the walls of the element, then fixing the walls in a deformed state and rigidly attaching them to the walls, stretching the walls of the latter into rectangular package, after which the ends of the walls are rigidly joined. Fig. 1 shows a prestressing diagram and a plot of the stress-strain state of two walls; in fig. 2 - tension element at the stand. The walls of a variable height of two lengthy building elements, for example, columns, formed by cutting with an oblique longitudinal cut are placed in a rectangle, as shown in FIG. 1 and are stretched by the force applied along the axis of symmetry of the rectangle. At the same time stretching two walls of variable height is dictated by the need to create in them uniformly distributed along the axis and width of the walls of the supports of normal stresses. If one wall is stretched in the longitudinal direction with a constant force (It), because of its variable height, it is impossible to obtain uniformly distributed diagrams of notional stresses. In the two walls of variable height, laid in a rectangle and rigidly fastened along the ends, the force in each section is distributed in proportion to the area of each wall. In any section of the walls, the stretching unit is distributed proportionally to the ratio of the areas: 1. -r, Cr2. , С С and the stresses remain constant along the length and width of the walls and are equal to: cTc: Normal stresses in both walls remain constant, as the force p is applied along the symmetry axis of the rectangle composed of two walls. The assembly and welding is carried out in the following sequence: 1. The sheet rectangular billet is cut out with a longitudinal cut, and thus walls 1 and 2 of the two columns are obtained. Walls 1 and 2 of variable height are placed on the table 3 of the tension stand in a rectangle. The ends of the pipe are welded to the grippers 4 and, thus, rigidly combined along the contour of the applied load. 2. After this, walls I and 2 are stretched with the help of hydraulic jacks 5 mounted on frame 6, given by the force P applied by the axis of symmetry of the rectangle. The force from the jack 5 is transferred to the grippers 4 through the tufts 7. After this, they are installed in the design position and pressed against the walls with the help of a clamp 10. The columns are assembled on the tacks, after which their walls are freed from the grips and welded to himself on both sides. The method of prestressing long elements of variable height allows a widening of the area of rational use of the prestressing of high strength steel in the frames of industrial buildings and will result in significant savings in steel due to the increased bearing capacity of the stretched walls. The invention The method of pre-stressing metal long I-sections by stretching the walls of the element, fixing the walls in the deformed state and rigidly attaching them to them, characterized in that, in order to ensure uniform stretching of the walls of the elements of variable height, to stretch Walls, the latter are placed in a rectangular package with their hemmed edges, and then the ends of the walls are rigidly joined. Sources of information taken into account in the examination 1. A. A. Kazimirov and others. Assembling and welding I-beams with pre-tensioning. Clear wall. Automata: sicca welding number 7, 1957, p. 5-7. 2. Authors certificate of the USSR N 547508, cl. E 04 C 3/10, 1975. - - / - g Fig: / j