RU2231464C2 - Method of production of prestressed reinforced concrete - Google Patents

Abstract

FIELD: water transport; repair of steel hulls of ships.

SUBSTANCE: proposed method includes concreting of section of bottom or deck strengthened with reinforcement. Prior to concreting, section of bottom or deck of ship is subjected to tension by means of cargo laid on deck.

EFFECT: enhanced crack resistance of concrete; reduced stresses due to prestress of section of bottom or deck.

2 dwg

Description

The invention relates to water transport and for the repair of steel hulls of ships.

A known method of repairing steel ceilings (bottoms, decks and sides) of the hull by laying reinforcement in the set spacings, connecting reinforcement with the elements of the set and subsequent concreting of the repaired overlap [1, 2].

The disadvantage of this repair method is the inability to use with this technology a progressive method of increasing the strength of concrete by prestressing it.

Known methods for creating prestressed reinforced concrete structures [3], the closest prototype of the invention is that the reinforcement is stretched before concreting and then fixed in tension on a rigid stand or form. After laying in the form of concrete and gaining the necessary strength by them, the reinforcement is released from the tensioning devices.

However, such a technology for tensioning reinforcement is not acceptable in ship's conditions, since tensioning devices will inevitably lead to deformation of the hull, which will lead to an unpredictable stress pattern of the section of the hull subject to concreting.

The problem to which the invention is directed, is to obtain the possibility of using prestressed reinforced concrete to reinforce worn ship floors.

The technical result of the invention is to increase the crack resistance of concrete by reducing the tensile stresses acting in it by prestressing the sections of the body subjected to concreting.

The mentioned result is achieved by the fact that the concreted section of the bottom or deck of the vessel, which is afloat, is pre-stretched by means of a load laid on the deck in a certain way.

The drawings show the implementation of the method of forming tensile stresses:

- figure 1 - in the bottom floors of the vessel;

- figure 2 - in the deck ceilings of the vessel.

According to the proposed method (see Fig. 1), before concreting a portion of the bottom 1 on the hull of the vessel 2, afloat, previously on the deck, in its middle part, a certain amount of cargo 3 is laid, so that the hull acquires a deflection, and the bottom is stretched. In this case, tensile stresses appear both in the sheathing sheets, and in the longitudinal elements of the set, and in the longitudinal rods of the reinforcing grills installed in the spacings of the single set. In this stressed state, the bottom floor 1 is concreted, and after the concrete has hardened, the load 3 is removed from the deck. After removal of the cargo 3, the hull of the vessel restores the initial undeformed state, and pre-compression stresses occur on the bottom section 1.

In the case of concreting section of the deck 4 (see figure 2) achieve tensile deformation on the deck of the ship. To do this, on the hull of the vessel 2, afloat, previously on the deck at the ends of the vessel, a certain amount of cargo 3 is laid, so that the hull of the vessel is deformed, and the portion of the deck 4 is stretched. In this case, tensile stresses appear both in the sheathing sheets, and in the longitudinal elements of the set, and in the longitudinal rods of the reinforcing grills installed in the spacings of the single set. In this stressed state, deck deck 4 is concreted, and after concrete has hardened, cargo 3 is removed from the extremities of the vessel. After removal of the cargo 3, the hull of the vessel restores the initial undeformed state, and pre-compression stresses occur on the deck section 4.

Subsequently, during normal operational loading of a vessel with scheduled cargoes, these compression stresses may increase or decrease, but tensile stresses will always be less by the amount of preliminary compression. This mode of stress correction is favorable for reinforced concrete sections of the vessel, which have an increased margin of safety against compression stresses, but are very sensitive to tensile stresses.

Sources of information

1. Telyaner B.E., Turmov G.P., Finkel G.N. Ship hull repair technology. - L .: Shipbuilding, 1984, p. 273.

2. Auth. St. USSR No. 347233, M. cl. B 63 B 5/20, 1972.

3 Building structures: Textbook. /Under. ed. V.N. Baykova, G.I. Popova. - M .: Higher. school., 1986. - 543 p. (prototype).

Claims (1)

A method of creating prestressed reinforced concrete in a composite hull structure by concreting a section of the bottom or deck, reinforced by reinforcement fixed in the spacings of the blank set, characterized in that before concreting, the section of the bottom or deck of the vessel is pre-stretched by means of cargo placed on the deck of the vessel.

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