FI89400C - Beam Construction - Google Patents

Description

, 89400

Beam structure - Balkkonstruktion

The invention relates to a beam structure with two flange parts and a web part made between them, made of diagonal steel bars arranged in three layers so that the bars in the outer layers are substantially parallel to each other and the bars in the intermediate layer are transverse to the bars in the outer layers.

Our previous patent application FI 904137 discloses a girder structure beam, the light web part of which is made of a diagonal sheet metal mesh. Many beams are still known, the web parts of which are made of metal trusses.

The disadvantage of the known beams is e.g. the fact that a lot of expensive steel raw material is used in the web section. In a lattice web, long diagonal ties have to be dimensioned to be rigid to prevent buckling. A disadvantage of the plate-beam beam is the difficulty of positioning the equipment passing across the web. In addition, the adhesion of a possible concrete layer to a flat surface is poor. To prevent buckling of the plate-beam beam, it is usually necessary to use an unnecessarily thick plate.

A beam structure of the type mentioned at the beginning is known, for example, from SE patent publication 217301 and DE application publication 2263729. In these known beam structures, the bars of different layers are arranged so that there are only two bars at each junction, i.e. the bars are connected only in pairs. This arrangement does not provide optimal stability and rigidity in relation to the amount of material used.

The object of the present invention is to reduce the disadvantages of the known beam structures and to provide a beam structure in which the web bar layers are positioned and fastened relative to each other so that the whole beam structure becomes stronger and stiffer than known structures in relation to the amount of material used. This object is achieved by the beam structure according to the invention in such a way that the parallel bars of the outer layers are aligned in pairs, whereby three different bar layers are connected to each other at the intersections of the bars.

In this case, the parallel overlapping bars act in pairs and can receive compressive forces well. The bars acting in pairs stiffen the entire web, so that the web of the beam also gets a high lateral stiffness.

A large number of different embodiments can be found for the invention. The following figures are intended to be illustrative only and to illustrate the operation of the invention. The positions of the structures can be selected arbitrarily. For the sake of clarity, the explanations of the figures speak e.g. from below and above, although it may also be a question of different lateral directions.

Figure 1 shows a side view of a part of a beam according to the invention, showing a diagonal bar net.

Figure 2 shows an illustrative view of a 3-layer steel bar net.

The main object of the present invention is to provide a light and inexpensive beam. The aim is to make the most of the steel by dividing it into a bar mesh, where the length of a single bar remains small between the welded knots. In this case, buckling is prevented even with small amounts of steel. The reinforcing bars in the different layers, which are bonded together by welding, also form a laterally rigid structure. The invention makes it possible to make structures with high bending stiffness. In this way, even during long spans, subsidies during construction work can be avoided. The 3,394,000 beams of the invention can also be temporarily superimposed to work together during critical installation steps.

Figure 1 shows a part of an elongate steel beam in which the diagonal steel bars 86 of the web form a steel bar network. The cross-arranged steel bars 86 in different directions are firmly welded to each other at all crossing points 94. Thus, in the event of a buckling, the sensitive free rod portion remains only between the two crossing points 94. The welding work of the rod network can be done reliably, for example with automatic hit-welding machines. The top flange 52 of the beam generally acts as a part for receiving compressive stresses. The lower flange 57 of the beam generally acts as a tensile stress receiving portion. The diagonal position of the steel bar net 86 is ideal for the transmission of forces. There are plenty of openings in the web between the rods 86, which lighten the structure and allow the passage of various devices. The web consists mainly or exclusively of diagonal steel bars 86.

The flanges 52 and 57 are steel plates to which the diagonal bar rods 86 of the web are welded. In this case, the diagonal steel bar mesh 86 consists of three layers of cross bars 86. The cross steel bars 86 are welded to each other at all intersections 94. In many cases, it is preferred there is a crossbar in between. In this way, for example, two bars are obtained in the compressed diagonals 86, whereby the possibility of buckling decreases. Figure 2 illustrates this in more detail. Paired diagonal bars stiffen the entire web laterally.

- Figure 1 shows only the flanges 52, 57 and the web 86, 94. In reality, the beam is usually provided with e.g. vertical supports at the ends of the beam and possibly also in the middle parts of the beam.

4 39400

The different diagonal rods 86b and 86c of the net web 86 receive different forces. At the intersections 94 of the net bars, e.g., the parallel diagonal bars 86c receive tensile stresses and the parallel diagonal bars 86b receive compressive stresses. The tensile and compressive stresses thus meet at the joint point. The tensile stress always tends to keep the rod and net straight, i.e. to prevent 1 stitching. Compression in tensioned directions in particular is advantageous for adding rods as shown in Figure 2.

Figure 2 shows a three-layer diagonal bar network in which parallel overlapping bars 86b act in pairs and can receive compressive forces well. Between the rods 86b are cross rods 86c. All three bar layers are welded to each other at the intersections 94. The paired bars 86b stiffen the entire mesh structure. In this way, the web of the beam also acquires a high lateral stiffness.

The beam can be placed in a concrete mold on one side. If desired, steels parallel to the base 57 can be added to the side in the mold for tensile stresses. Once the cast concrete has hardened, a beam suitable for many uses is obtained. The other flange side of the beam can also be cast in concrete in the same way. This results in a strong reinforced concrete structure.

The type of steel bars used in the invention may be arbitrary. The cross-section of the bars can be, for example, round, rectangular, plate-shaped or tubular. The surface of the bar can be smooth, profiled lengthwise or provided with grips, for example for concrete.

The embodiment of the beam can be, for example, a bridge so that the bridge support system is made of beam structures according to the invention. In addition to small pedestrian bridges, heavily loaded bridges may come into question.

5 S94CO

The rod net used in the solution according to the invention is much more rigid than the rod net.

Claims (4)

6 89400 A beam structure having two flange portions (52, 57) and a web portion (86) interposed therebetween, made of diagonal steel bars arranged in three layers such that the bars (86b) in the outer layers are substantially parallel to each other and the bars in the intermediate layer (86c) are oriented transversely to the bars of the outer layers, characterized in that the parallel bars (86b) of the outer layers are aligned in pairs, whereby three different bar layers are connected to each other at the intersections (94) of the bars. 2. Balk enligt. The patent 1, which comprises a diagonal cross member of the cross member (86b, 86c), is fastened to the cross member (94) of the cross member. A beam according to claim 1, characterized in that the cross bars (86b, 86c) of the diagonal bar net of the web are welded to each other at each junction (94) of the bars. 3. A patent according to claim 1 or, in turn, having a diagonal flange (86b, 86c) fastened to the flange (57) or flange (52). A beam according to claim 1 or 2, characterized in that the diagonal bars (86b, 86c) of the web are welded to the lower flange (57) or the upper flange (52). Beam according to Claim 1 or 2, characterized in that the web part (86) is fastened to one of the flanges (52, 57) by means of concrete. 7 89400! * 1. Balkkonstruktion, som har tvä flänsdelar (52, 57) och nif-llan dessa fästad livedel (86) gjord av diagonala stälstänger, vilka anordnats i tre skikt sa, att stängerna (86b) i ytterskikten är sinsemellen listenterna ocriktade ocht 86c) in the case of rickshaws to the rear of the head, the head of the head (86b) is replaced by the head of the head (94b). 4. Balk enligt. claim. 1 or 2, kännetecknad av, att livdelen (86) fästats vid nägon av flänsarna (52, 5 /) med hjälp av betong.