SK87694A3 - Lattice girder - Google Patents

Abstract

Described is a lattice girder with at least one longitudinal rod (2) as the upper chord and at least one reinforcing bar (1) as the lower chord. Lateral struts (3) which originate at the lower chord and converge on the upper chord are welded to a longitudinal rod of the upper chord at two points spaced a certain distance apart. The top ends of the lateral struts (3) are bent outwards, from the plane of the struts, to form a loop (5).

Description

Technical field

The invention relates to a lattice beam with at least one longitudinal rod as the upper strand and at least one reinforcing rod as the lower strand, wherein the yoke extending from the lower strand is welded in its upper apex region with the longitudinal strand of the upper strand at two spaced locations.

The state of the art ...

A known lattice beam of this type (see DE 1953348) shows the spacing of the connection points of the yoke to the upper branch so that the radius of curvature of the yokes at the top can not be arbitrarily executed. This is largely non-functional at a minimum distance from the upper branch running substantially parallel to this apex section.

SUMMARY OF THE INVENTION It is an object of the invention to utilize a yoke in the apex region as a lateral strut. Of particular importance in this connection is the possibility of increasing the adhesion of the top strand and the surrounding concrete by a particular embodiment of the top region of the yoke.

SUMMARY OF THE INVENTION

The problem is solved according to the invention in such a way that the apex regions of the calipers are formed as an outwardly looped loop from the caliper plane.

These loops made according to the invention, which mediate the adhesion of the upper strand in the surrounding concrete, can in particular be improved by one. that the loops are made considerably longer than the known lattice beams. The loops should also be considerably longer than the distance between the contact points of the spaced semicircles with the longitudinal rod.

How far the set loops are to be bent from the caliper plane depends on the application. Of particular importance here is the possibility that the loops run parallel to the plane defined by the rods of the lower branch. In this case, the printed strip, which consists of the upper strand and its surrounding concrete layer, achieves maximum reinforcement. When inserting the designed lattice beam into the concrete formwork, the design with loops running parallel to the lower branch has the special property of connecting not only the lower branch but also the upper branch with adjacent formwork boards. To this end, it is particularly advantageous to provide that the clamps are parts of two parallel running coils.

In order to offset the strips from the formwork boards, it is preferably provided that the yokes extend over the longitudinal bars at a height and that the loops are spaced apart from the longitudinal bars. The connection can be made into loops which are flat to the formwork boards. The number of attachment points can be increased if the vertex regions of the calipers contain outwardly bent loop pairs.

Prefabricated ceiling slabs with lattice girders, which comprise loops running parallel to the plane of the lower leg, can also be stacked particularly well.

The basic inventive idea, i. In the context of the invention, a better utilization of the vertex region of the yoke as a lateral strut of the lattice beam can also be developed in particular in that the loops are connected to at least one other longitudinal rod. In addition to improving the fracture strength given by the loops themselves, such longitudinal bars can reinforce the upper

- J over its entire length or only in the momentum of the corresponding central region. They naturally also increase the adhesion of the upper branch and the surrounding concrete.

Overview of the figures in the drawing

Among the many possible embodiments of the invention, some exemplary embodiments are shown in the accompanying drawings, in which FIG. show:

Fig. 1, FIG. 2 fig. 3, FIG. 4 fig. 5, FIG. 6 fig. 7 fig. 8 fig. Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig. 14 Fig. 15 Fig. 16 a front view of the first exemplary embodiment, corresponding schematic representation, upper branch region of the second exemplary embodiment, respective schematic representation, upper branch region of the third exemplary embodiment , respective schematic representation, upper branch region of the fourth embodiment, respective schematic representation, upper branch region of the fifth embodiment, respective schematic representation, upper branch region of the sixth embodiment, respective schematic representation, schematic representation of the seventh embodiment, the respective elevation and elevation of the eighth embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The lattice beam shown comprises exactly two reinforcing bars X, which together form the lower leg, and one longitudinal bar 2, as the upper leg. The side reinforcement between the upper and lower branches serves as a system of yokes 3, which is formed by a continuous wire snake. Each yoke together with part of the lower branch forms an isosceles triangle whose apex region is connected to the longitudinal bar 2 of the upper branch. The formation of the loops 4 in the region of the connection of the yokes 3 to the stiffening bars χ of the lower strand serves (see AT-PS 373 012) in particular to locate corresponding additional bars not shown here parallel to the stiffening bars X in the present case. - - -............

Of the inventive nature, those loops 5 which are offset from the plane of the stirrups X, which are in the region of the connection of the stirrups X to the longitudinal bar 2. These loops 5 serve to improve the connection of the upper strand to the surrounding concrete. In the sense of this function, these loops can be elongated and possibly as shown in FIG. 7 and 8, even wrapped.

If the loops 5 run parallel to the reinforcing bars X in a folded plane, this will facilitate the use of the lattice beam as a spacer for the formwork of the concrete jacket. In addition, the lattice beams shown in FIG. 1 and 2 well stackable.

For the embodiments of FIG. 3-12, the arrangement of the additional longitudinal rods is common. These may extend over the entire length of the grating or only in part. They improve not only the fracture strength of the upper branch, but also its connection with the surrounding concrete. According to FIG. 3 to 8, just two symmetrically arranged additional longitudinal bars 2, according to FIGS. 9-12 shows a single additional longitudinal bar 2, which in the exemplary embodiment of FIG. 11 and 12 in the form of a metal rail.

In both exemplary embodiments of FIG. 13 to 16, the two yoke planes, i.e. the planes of the wire coils, are mutually parallel, as shown in particular in FIGS. 15 and 16. The yokes 3 are fastened here to the lower rod 1 and the upper rod

2. made up of U-profiled sheet metal rails and overlap them by a dimension which ensures that the sheet metal rails are covered with concrete. The open sides of the metal rails can, as is apparent from FIG. 15. 16 apart. However, an equally arranged arrangement of the two grooved sheet metal rails is also possible. The tops of the stirrups form pairs of loops 5, which in both of these embodiments are particularly suitable for strengthening on the formwork boards.

A number of exemplary embodiments can be extended. and yet the previous illustration shows that the design of the top region of the yokes connecting the upper branch and the lower branch according to the invention opens up a number of new design possibilities for the lattice beam designer.

Claims (9)

PATENT CLAIMS A lattice beam with at least one longitudinal strand (2) as the upper strand and at least one longitudinal strand (1) as the lower strand, wherein the yoke extending from the lower strand (3) with the upper apex region is welded to the longitudinal strand (2) of the upper strand at two spaced points, characterized in that the apex regions of the calipers (3) are formed outwardly from the plane of the caliper (3) by bent loops (5). The grating according to claim 1, characterized in that the loops (5) have spaced semicircles substantially greater than the distance between their contact sides with the longitudinal bar (2). A lattice beam according to claim 1 or 2, characterized in that. that the loops (5) extend parallel to the plane defined by the longitudinal bars (1) of the lower branch. The grate according to one of claims 1-3, characterized in that the yokes (3) are part of a wire snake which also forms loops (4) bent from the yoke plane on the lower branch. The grating according to one of claims 1 to 4, characterized in that the loops (5) are connected to at least one other longitudinal rod (2, 2). Lattice beam according to one of Claims 1 to 5, characterized in that the loops (5) are angled towards the central longitudinal bar (2) of the upper strand. The grating according to claim 4 or 5, characterized in that the brackets (3) are parts of two parallel running coils. Here ΒΥό-ς'ί The grate according to one of claims 1 to 7, characterized in that the yokes (3) extend over the longitudinal bars (1, 2) and the loops (5) are offset at a distance from the longitudinal bars (1, 2). The grating according to one of claims 1 to 8, characterized in that the apex regions of the yokes (3) have pairs of loops (5) bent out of the yoke plane.