DE232414C - - Google Patents

Description

IMPERIAL

K PATENT OFFICE.

PATENT LETTERING

~ JVl 232414 - ■ CLASS 37b. GROUP

Patented in the German Empire on November 15, 1908.

The armature iron are the currently known lattice girders made of iron and reinforced concrete the reinforced concrete bars with the exposed iron bars by means of rivets or Bolts united to form a closed framework. This arrangement of the iron framework encounters a difficulty in the truss in the case of significant staff members, consisting in that while the exposed iron bars in

ίο these cases made of rolled iron of significant cross-sectional dimension or are to be made from bar irons riveted to one another, the use Such iron parts for the iron reinforcement of the reinforced concrete rods out of consideration for a proper reinforced concrete connection are not 'is appropriate. In the case of significant axial stresses in the reinforced concrete rods rather the iron reinforcement of the latter from a large number of loosely laid side by side Iron rods consist of relatively small cross-sectional dimensions. This fact gives rise to in the named Cases of a direct connection between the iron reinforcement of the reinforced concrete bars and to distance itself from the exposed iron rod system and the context to accomplish between these construction parts through the concrete. It becomes through it possible to design the two construction parts mentioned completely independently of one another and in this way what is essentially different for the two parts To take construction requirements into account.

However, such an arrangement requires special devices in major designs in the nodal junctions of the bars made of exposed iron to those out Reinforced concrete in order to cope with the significant main and secondary stresses of the truss in these 40 Facing bodies with a sufficient degree of security. A suitable one for the cases mentioned Junction connection between the bars made of exposed iron and those made of reinforced concrete in a lattice girder composed of such rods forms the object of the present invention and is illustrated below in a drawing Application example presented and explained.

Fig .. ι represents a truss node in elevation,

FIG. 2 shows a section along the line AA in FIG.

Fig. 3 is a plan view of the node.

All exposed iron parts and those in the drawing only through the concrete appear covered are shown by solid lines.

In the node arrangement shown, two exposed truss rods χ and y meet with a truss compression belt ζ made of reinforced concrete. In accordance with the significant bar forces for which the nodal arrangement is calculated, the compression bar χ is made from two angle irons riveted together to form a single bar with a lining plate in between, the tension bar y is made from a flat bar of considerable width.

set (Fig. ι). In this form, the iron rods χ and y are for a connection with the concrete by means of countersinking, in the latter not suitable because their adhesion surfaces on the concrete would be too small in relation to the forces to be transmitted, and on the other hand, because of the significant, uninterrupted and parallel to the compressive stresses of the reinforced concrete belt ζ

ίο running separation surfaces in the concrete, the internal cohesion of the concrete mass would be too much impaired. In consideration thereof, the two iron bars are χ and y in their meeting points with the concrete (with s or s 'in Fig. I) aborted and α at their ends by means of riveting, each with a pair of spaced projecting angle iron, α' and b, V connected which angle irons from the mentioned meeting points s and s' run parallel to the axes of the iron bars χ and y in the concrete and convey the power transmission between the latter iron bars and the concrete by virtue of adhesion to the latter. Each of the bars a, a !, b, V is enclosed on all sides by concrete and dimensioned in such a way that the adhesive tension does not exceed the permissible limit. There are thus χ are not suitable for direct connection with the concrete iron bars and y at their meeting points with the concrete in groups of rods of iron dissolved, which the χ in the axes of the rods and y acting Druckbzw. Introducing tensile stresses, the so-called principal stresses, into the concrete in a completely safe way.

In the case of significant designs of lattice girders, however, in addition to the main stresses, the so-called secondary stresses in the node connections must be taken into account, ie those stresses that arise as a result of elastic deformation of the lattice girder. In consideration of these tensions, special iron bars c, c ' and c " are arranged, which, running parallel to the plane of bending of the beam in the concrete, first meet the concrete surface with the bars a, a!', B and b ' and with the latter according to the drawing are connected by rivets, so that from each of these riveted connections at least two iron rods run parallel to the plane of curvature of the beam and radiate in different directions in the concrete (rods c and a ; c, a! and c ' ; c', b and c " ; V and c" in Fig. 1; the bars c, c ', c " are made coherent in the present example by forming sections of a double-bent iron bar (Fig. 1). The purpose of this Adordnung is applied to the rod group c illustrated and α (Fig. I ^. In the distortion of the geometrical axis structure of the truss due to elastic deformation of the latter suffer χ the rods and y deflections. The consequence in the concrete on the contact surfaces with the iron rod a The secondary stresses that arise are directed transversely to the bar α and are particularly dangerous to the surface of the concrete for the existence of the latter. The harmful influence of the stresses mentioned is substantially reduced when the bar c, which is also arranged transversely to the bar α , is mediated by the rivet η ( Fig. 1) picks up the reaction of the bar α and transfers it to the lower parts of the concrete.

As is clear from what has been said, the new device consists in the fact that the rod χ or y splits at the transition point into the concrete into several iron rods which, from the point mentioned, parallel to the plane of bending of the beam and in different directions in the concrete run and mediate the power transmission between the exposed iron rod and the concrete. By arranging a correspondingly large number of intermediary iron rods, the transmission of significant main stresses between the exposed iron framework rods and the concrete can be accomplished with a sufficient degree of safety. By simultaneously counteracting the secondary stresses in the concrete, it is possible with the device described to refrain from a direct connection between the exposed iron rods and the iron fittings of the reinforced concrete rods. in the present example consisting of round iron r, becomes complete. arranged and executed independently of the exposed iron bars.

Claims (1)

Patent claim: Junction point connection for iron girders with articulated wall and with reinforced concrete pressure belt, characterized in that the bars of the wall structure are cut off immediately before entering the pressure belt are and their continuation in several, with the flat sides facing each other Find iron bars that are between the rebar of the compression chord and run symmetrically to the bending plane of the beam. ■. · ■ 1 sheet of drawings.