SU935583A1 - Prestressed beam - Google Patents

Description

(5) PRE-STRESSED BEAM

The invention relates to the construction and can be used as the main supporting structures for building coatings, spans of transport and other structures.

A well-known pre-tensioned beam includes a tightening, the ends of which are fixed on the stops, and a spacer placed in the center of the beam between the lower one and the pull-in.

The spacer located in the center, made in the form of a rack, welded to the bottom of the Cy 1.

However, the welds of the fastening of the spacer element are an additional focus of stress concentration in the stretched bottom along the beam. In addition, bench equipment and complex control are necessary to make this design. There is also no sufficient reduction in the material intensity of the beam, due to the presence of large forces in it.

The closest in technical essence and the achieved result to the proposed invention is a pre-stressed beam, including a choke, the ends of which are fixed on stops, and a spacer element.

However, the straight outline of the beam does not provide a sufficient increase in the carrying capacity, since the shoulder tension of the tension in tension relative to the center of gravity of the beam remains small due to the limitations of the beam height and transport conditions.

Therefore, to create the required pre-tension of the beam, it is necessary to continue to pull the pulling force, you need a large-diameter roller, which increases to irrational

20 sizes of the construction height of the beam.

Claims (2)

In addition, due to the presence of the vertical component pulling force at the inflection point where the roller is in contact with the tie, the cat only has one elastic support for the beam and divides it only into two spans, which does not sufficiently increase the bearing capacity of the beam and not enough reduces its consumption of materials. The aim of the invention is to reduce the material consumption of the pre-stressed beam. . This goal is achieved by the fact that in a prestressed beam, including a tightening, the ends of which are fixed on supports and a expansion element, the beam is made M-shaped, and the expansion element is formed by the V-shaped part of the beam, and the beam is provided with additional tightening connecting the tops of the upper corners of the beam axis fracture. The end, the ends of which are fixed on supports, is attached to the top of the lower corner of the fracture. The drawing shows the proposed pre-stressed beam. Pre-stressed M-neck on beam 1 with support hinges 2 at the ends contains a pull 3, fixed with ends at the ends, and at the point of inflection to the top of the central angle of the fracture and pull 4 placed at the level of the vertices of the two extreme points of the fracture. Zatka 3 is made of high strength steel. After production of beam 1, the ends of the knot k are attached to it at the level of the vertices of the two extreme angles of the fracture. Then tightening 3 in the straight-line condition with the ends attached to the ends of the beam 1 Then, using jacks or a winch, tighten the tightening 3 to the central angle of fracture of the beam 1 and attach it to it. Performing a pre-stressed M-shaped beam . The two extreme angles of the fracture are located one at a time, and the central one - on the other side of the straight line passing through the support hinges, allows the expansion element to be combined with the beam and to create the necessary preliminary stress of a variable quantity. the length of the beam with a small tension in the tie, the ends of which are fixed to the stops or ends, since the lengths of the tension arms of the tension tightening relative to the center of gravity of the beam cross sections can be chosen large enough values without prejudice to choosing a rational construction height of the beam transportation. The rational choice of the construction height of the beam is due to the fact that the inclined external branches of the beam enable the direct construction of the roof slopes. The location of the two extreme angles of the fracture one at a time and central on the other side of the straight line passing through the support hinges causes the appearance of a vertical component of the tension tension attached to the ends on the stops or the ends of the beam. The introduction of an additional tightening into the level of the vertices of the two extreme angles of the fracture of the beam allows one to create a preliminary stress in it on the peri-preload. Under the action of an external load on a beam, the tension of the upper thrust together with the tension in the lower thrust and its vertical component transmitted through the internal branches of the beam to the upper corners of the fracture causes the formation of a system of force factors corresponding to the two resiliently supported supports on which inner ends of the outer branches of the beam. The force factors of each of the formed elastically stiffened support are the moment of pulling tension forces and part of the vertical component of the tension of the lower puff acting on the inner end of each of the outer branches of the beam. As a result, the pre-stressed beam is likened to a three-span continuous beam supported at the ends on the pivot bearings, and in the gap to two elastically compliant supports, which contributes to an increase in its carrying capacity and a reduction in material intensity. Attaching the bottom hook at the point of the bend to the top of the centoal angle of the beam fracture does not allow the hook to slide off the corner of the fracture during the beam operation. - 9 , . The use of the proposed pre-stressed beam in comparison with the known beam ensures a reduction in the material intensity by 1, times, and in comparison with the standard part used in construction, it provides the economic effect of reducing the material intensity by 65-70 % The theoretical substantiation of the technical and economic efficiency of the invention is made on the basis of the developed technical design pre-stressed beam. Claim 1, Pre-tensioned beam, including tightening, the ends of which are fixed on supports, and expansion element, characterized in that, in order to reduce material capacity, the beam is made M-shaped and the expansion element is formed by a V-shaped beam , moreover, the beam is equipped with an additional tightening,. connecting the top of the upper corners of the fracture axis of the beam. 2. A beam according to Claim 1, characterized in that the puff, the ends of which are attached to the supports, is attached to the top of the lower corner of the fracture. Sources of information taken into account in the examination 1.Bele E- I. Pre-stressed bearing metal structures. M., stroiizdat, 1975 p. 120 2. USSR author's certificate f 6991 2, cl. E Of C 3/10, 1978.