SU114803A2 - Butt connection of precast concrete elements - Google Patents

Description

BASIC Auth. St. No. 108940 decommissioned butt joining of prefabricated reinforced concrete structures using metal plates and transverse bolts embedded with cement mortar in metal tubes, in which, in order to avoid working bolts for shearing and removal, each metal pad is clamped between nuts and bushings screwed on the ends of the bolts, with the force from the pads being transferred to the concrete through steel pipes, at the ends of which there are bushings.

 Butt joints cause a significant consumption of high-strength steel for the manufacture of bolts connecting the plates.

In the proposed butt joint, the consumption of high-strength steel is significantly reduced without compromising the strength of the structure. This is achieved by making the bolts connecting the plates with the joined elements made up of three parts, only two extreme parts of each bolt are made of high-strength steel, and the middle part of it is made of ordinary steel.

FIG. Figure 1 shows an exemplary embodiment of the proposed butt joint in section along the longitudinal axis of the connected elements; in fig. 2 shows a section but AA in FIG. 1; in fig. 3 is a section through BB in FIG. one; in fig. 4 - on a larger scale, a bolt connecting the pads.

The proposed joint connection of prefabricated reinforced concrete structures consists of metal plates 1, steel pipes 2, washers 3, bushings 4, bolts 5 of high strength steel, bolts 6 of ordinary steel, rebar 7, clamps 8 R 9.

.№ 114803

The force at the joint is perceived by metal plates / through the forces of friction arising due to the tension of the bolts 5. The latter are screwed into the sleeves 4 and through them transmit the force to the metal tubes 2, and those in turn to the concrete. The sleeves 4 are interconnected by bolts 6. The annular space between the tubes and the bolts is filled with high-strength cement mortar.

In order to better distribute the force transmitted by the tubes 2 to the concrete, and to increase its resistance to compression, reinforcement meshes 7 and clamps 8 to 9 are used.

The manufacture of the butt joint elements is carried out as follows.

The entire frame, assembled from tubes 2 with bushings 4, bolts 6, grids 7 and clamps 8 to 9, is installed in the formwork and, after the rest of the reinforcement has been assembled, is concreted.

The holes in the lugs for the passage of the bolts are made with the necessary tolerances, i.e., they exceed the diameter of the bolts, as a result of which the work of the bolts for shearing and washing is excluded.

Bolts 5 are placed during installation, which eliminates the presence of protruding parts from the structure. The bolts 5 are of high strength steel, subjected to quenching and tempering. The washers 3 and the sleeves 4 are made of hardened steel. The sleeves 4 are internally threaded for bolting 6 together and screwing bolts 5 into them. The threading on bolts 6 is done only at their ends; in their middle part, i.e., between the inner edges of the sleeves 4, there are no cuts.

The assembly of the joint consists in setting the pads, screwing the bolts 5 into the sleeves 4 and screwing them at a certain torque. Due to this, the linings are clamped between the washers 3 and the sleeves 4 in the bolts 5, stretching occurs, and in the contacting planes between the washers and the linings the friction reaches such a value that the force from the linings is perceived by the bolts through the friction forces.

The prestresses in the concrete and the reinforcement are created by the tension of the reinforcement beams placed in the tubes W and terminated by anchors // supported on the sheets 12.

At the site of completion of the assembly and tensioning of the bolts, the structural elements immediately come into operation.

Subject invention

Butt joint of precast concrete elements according to ed. St. Alb 108940, characterized in that, in order to replace high-strength steel with ordinary steel without sacrificing structural strength, the bolts connecting the pads with the abutting elements are made of three parts, the two extreme parts of each bolt being made of high-strength steel, and its middle part - from ordinary steel.

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FIG. one

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Section 66, Lapt F