RU93105U1 - REINFORCED CONCRETE COLUMN - Google Patents

Abstract

 Reinforced concrete column consisting of concrete and high-strength rod reinforcement subjected to preliminary tension in the stretched zone and preliminary compression in the compressed zone, characterized in that the column in the longitudinal direction has a stepped profile, and the tensile reinforcement breaks in the span in accordance with the diagram of materials.

Description

The utility model relates to construction and can be used as supporting structures of buildings.

Reinforced concrete columns with prestressed reinforcement stretched over the entire length of the column are known (See Gabrusenko V.V. “Fundamentals of the calculation of reinforced concrete in questions and answers”, 2002, p. 26).

The closest technical solution is a reinforced concrete column with pre-stretched reinforcement stretched over the entire length of the column (see I. Tikhonov, “Reinforcement of Elements of Monolithic Reinforced Concrete Buildings”, 2008, p. 52). The fittings are inserted into the mold prior to concreting the element, one end is fixed in the stop, the other is pulled with a jack or another device, to the specified controlled voltage. After the concrete has acquired the necessary transmission strength, the reinforcement is released from the stops. Reinforcement during restoration of elastic deformations in conditions of adhesion to concrete compresses the surrounding concrete.

However, in this device, prestressed reinforcement is stretched from one end of the column to the other, which leads to a large overspending of materials and an excessive margin of safety in less stressed sections of the columns.

In order to eliminate this major drawback and significantly reduce the consumption of high-strength steel and concrete, a new design solution is proposed in which the column has a stepped profile that allows breaking off the tensile reinforcement in the span in accordance with the diagram of materials (- a graph of the change in the strength of sections depending on the consumption of materials variable along the length of the element. See, for example, Aksenov BG, NB Aksenov Reinforced concrete floors. Rostov-on-Don, 1996.).

The essence of the utility model is that a reinforced concrete column consisting of concrete and high-strength bar reinforcement subjected to preliminary tension in the stretched zone and preliminary compression in the compressed zone, while the column in the longitudinal direction has a stepped profile, and the tensile reinforcement breaks in the span in accordance with a plot of materials.

In the proposed solution, unlike the standard one, a combined prestressing is adopted, in which the high-strength reinforcement of the stretched zone is subjected to preliminary tension, and the compressed zone - to preliminary compression. This will not only increase the crack resistance of the stretched zone, but also increase the stresses in the reinforcement of the compressed zone before the destruction of the compressed concrete to the value Rsc + σ'sp.

In the proposed solution, breaks of high-strength longitudinal reinforcement are provided in both compressed and stretched zones.

The essence of the reinforced concrete model is illustrated in the drawing, where:

Figure 1 - Profile of reinforced concrete columns

Figure 2 - sectional dimensions of a reinforced concrete column and its reinforcement in section AA

Figure 3 - the same, in section bb

Figure 4 is the same, in the context of CC

Figure 5 is the same, in section D-D

6 is a diagram of the tension of the reinforcement

Reinforced concrete column 1 has concrete ledges 2, creating a stepped profile.

The torn off prestressed reinforcement 3 and 4 is anchored in the concrete ledges of 2 columns 1 having a stepped profile. The pre-tension forces from the jack to the reinforcement 3 are transmitted through the inventory rods 5, and the pre-compression forces are transmitted in the same way, but through rigid inserts. Anchoring prestressed reinforcement 3, 4 is carried out by collet clamps 6.

The stability of reinforcing bars during preliminary compression is ensured by their binding by wire at the points of inflection to the transverse reinforcement, and of the entire reinforcing cage as a whole - by focusing on the walls and bottom of the steel formwork.

The manufacture of the column is carried out in the usual manner. At first, the reinforcing cage is assembled taking into account the stepped profile 2 of column 1, which allows breaking off the stressed reinforcement 3 and 4 in accordance with the diagram of materials. Then the reinforcing cage is installed in the formwork and secured. Next, we pre-stretch and compress reinforcement 3 and 4 with the transfer of reactive forces to the stands of the bench or to the ends of the power formwork. Then the columns are concreted and after the concrete has set the required strength, the reinforcement 3 and 4 are released from the stops (the transfer of prestresses from the reinforcement 3 and 4 to the concrete when the concrete reaches the transmission strength). Prestressed reinforcement 3 and 4 are anchored in concrete ledges 2 of column 1 using collet clamps 6. Column stripping is performed when concrete reaches formwork strength.

For comparison, a prestressed reinforced concrete column is adopted. The longitudinal reinforcement of the column is constant over the entire length.

The flow rate of longitudinal high-strength reinforcement during breakage of reinforcement in the stretched and compressed zones in comparison with a prestressed reinforced concrete column with reinforcement along the entire length is reduced by 12.5%. And with cliffs only in the stretched zone - by 9%.

Claims (1)

Reinforced concrete column consisting of concrete and high-strength rod reinforcement subjected to preliminary tension in the stretched zone and preliminary compression in the compressed zone, characterized in that the column in the longitudinal direction has a stepped profile, and the tensile reinforcement breaks in the span in accordance with the diagram of materials.