RU2167985C1 - Pre-stressed tubular-concrete member with fan reinforcement - Google Patents

Abstract

FIELD: construction engineering; erection of building structures subject to eccentric compression. SUBSTANCE: pre- stressed member has external case made in the form of metal tube, concrete kernel made of self-stressing concrete and core installed in the latter; core is assembled of high-strength die-rolled section reinforcing bars; mentioned bars ensure adequate cohesion with concrete; they are fanning out from center to ends of case and are rigidly fixed in case holes by means of arc welding. Supporting slabs are fastened on ends of external case to form enclosed space providing for pre-stressing in tubular-concrete member and for joining beams of floors, coverings, and other structures. Tension stresses will be set up in reinforcing bars after concreting the member due to self-stressing concrete kernel located inside case; mentioned tension stresses will cause bending of member due to their fan pattern. Applying eccentric thrusts to tubular-concrete member will first cause backward bending, and only after that member will sag to extent below rated by amount of backward bending, that is, strength of tubular-concrete member will be very high. EFFECT: improved stability of structure; enhanced bearing capacity; reduced metal input. 2 dwg

Description

 The invention relates to the field of construction and can be used in the manufacture of structures operating on eccentric compression.

 Known design, working in compression, which is a metal pipe filled with concrete (see A.I. Kikin, R.S. Sanzharovsky, V.A. Trul Designs of steel pipes filled with concrete.- M .: Stroyizdat, 1974, p. 64).

 The disadvantages of this design are its large dead weight, significant metal consumption, and reduced stiffness.

 The closest in technical essence to the claimed invention is selected as a prototype high-strength reinforced concrete element, working in compression and containing an outer metal shell, a concrete core and a core placed in it; Support plates are fixed at the ends of the outer shell, the core is made in the form of longitudinal high-strength rods grouped in bundles or ropes, and in the base plates grooves are made in which the ends of the longitudinal rods are wound (ed. St. USSR N 580292, E 04 C 3/30 , 1977).

 The disadvantage of this design is, firstly, that the concrete core of the element is not intended primarily for the perception of compressive loads, but to prevent the loss of stability of high-strength rods parallel to the longitudinal axis of the element. Secondly, the reinforcement adopted in the prototype does not ensure the stability of the reinforced concrete element itself under the action of significant compressive loads applied with a large eccentricity.

 The technical result is an increase in the stability of a pipe-concrete structure working for eccentric compression, while increasing the bearing capacity and reducing the metal consumption.

 The specified technical result is achieved by the fact that in the concrete element contains an outer shell in the form of a metal pipe, a concrete core and a core placed therein. The peculiarity is that the core is made in the form of reinforcing bars that fan out from the middle to the ends of the shell - the pipe and is rigidly fixed in its body.

 In addition, the core is made of tensile concrete, and base plates are fixed at the ends of the outer shell, which serve to create an enclosed space that provides prestressing in the concrete element, as well as connecting the element with floor beams, coatings and other structures.

 Due to the presence of a core of tensile concrete inside the core, tensile stresses arise in the reinforcing rods of the core immediately after concreting the element, which, due to the fan arrangement of the rods, leads to the bending of the element along the entire length.

 When a load is applied to a pipe-concrete element with an eccentricity, the reverse bend is first selected and only then can the element bend, the value of which in the proposed design will be less than the calculated one by the value of the reverse bend, that is, the stiffness of the pipe-concrete element will be increased without increasing the cross section.

 The analysis of the prior art by the applicant made it possible to establish that the applicant did not find an analogue characterized by features identical to all the essential features of the claimed invention.

 The definition of the prototype allowed us to identify a set of essential distinguishing features in relation to the technical result in the claimed solution.

 Therefore, the claimed invention meets the condition of "novelty."

To verify the compliance of the claimed invention with the condition "inventive step", the applicant conducted an additional search of the known, in order to identify features that match the distinctive features of the claimed device from the prototype. The search results showed that the claimed invention does not follow explicitly from the prior art determined by the applicant for the specialist, the effect of the transformations provided for by the essential features of the claimed invention on the achievement of the technical result is not revealed, in particular, the following transformations are not provided for by the claimed invention:
- addition of a known product by any known part (s) attached to it according to known rules to achieve a technical result in respect of which the effect of such additions is established;
- replacement of any part (s) of a known product with another known part to achieve a technical result, in respect of which the effect of such a replacement is established;
- the exclusion of any part (element) of the product with the simultaneous exclusion of its function and the achievement of the usual result for such exclusion (simplification, reduction of mass, dimensions, material consumption, increased reliability, etc.);
- an increase in the number of elements of the same type to enhance the technical result due to the presence in the tool of just such elements;
- the implementation of a known tool or part (s) of a known material to achieve a technical result due to the known properties of this material;
- creating a tool consisting of known parts, the choice of which and the connection between them are based on known rules, recommendations, and the technical result achieved in this case is due only to the known properties of the parts of this tool and the connections between them.

 The described invention is not based on a change in a quantitative characteristic (s), the presentation of such signs in relationship or a change in its appearance. This refers to the case when the fact of the influence of each of these characteristics on the technical result is known, and new values of these signs or their relationship could be obtained on the basis of known dependencies and patterns.

 Therefore, the claimed invention meets the condition of "inventive step".

 The drawings show the longitudinal (Fig. 1) and transverse (Fig. 2) sections of the proposed element.

 The pipe-reinforced concrete prestressed element with fan reinforcement consists of an outer shell in the form of a metal pipe 1, a concrete core 2 made of tensile concrete, and a core placed in it, which is a high-strength reinforcing rods 3 of a periodic profile, fan-shaped diverging from the middle to the ends of the shell 1 and rigidly fixed in its holes 4 using arc welding. Base plates 5 are fixed at the ends of the outer shell.

 The number of reinforcement, its class and degree of stress (brand of tensile concrete) should be established by calculation according to SNiP 2.03.01-84 "Concrete and reinforced concrete structures" depending on the specific design scheme.

 The manufacture of the element and its subsequent work are as follows.

 A metal pipe 1 of a certain diameter and the required length is taken. On the pipe surface, holes 4 of the required diameter are drilled with countersink, into which the reinforcing rods 3 of the periodic profile are then inserted and welded by arc welding flush with the outer surface of the pipe 1. Then the pipe is sealed from one end by the base plate 5 by welding around the entire perimeter by arc welding.

 The prepared pipe is filled with a plastic concrete mixture on a tensile cement with a seal on a vibrating table or a deep vibrator. After concreting, the pipe is drowned from the second end by a second base plate having a small hole for the final filling of the inner space of the pipe.

 Hardening of the molded structure can be carried out under normal conditions or subjected to heat and moisture treatment in order to accelerate hardening of concrete.

 After the concrete reaches its design strength, tensile stresses arise in the core reinforcing rods, which, due to their fan arrangement, lead to the bending of the element along its entire length. After that, the pipe-concrete prestressed element can be subjected to operational loading.

Thus, the above information indicates the following conditions are met when using the claimed device:
- a tool embodying the claimed device in its implementation, is intended for use in construction, namely as a column of frames of multi-storey buildings, racks, piles, heavy-loaded machine frames, bridge spans, etc .;
- for the claimed device in the form described in the independent clause of the claims, the possibility of its implementation using the means and methods described in the application or known prior to the priority date is confirmed;
- a tool embodying the claimed invention in its implementation, is able to ensure the achievement of the perceived by the applicant technical result.

 Therefore, the claimed invention meets the condition of "industrial applicability".

Claims (1)

 Pipe-concrete pre-stressed element with fan reinforcement working for eccentric compression, containing an outer shell in the form of a metal pipe, a concrete core and a core placed in it, characterized in that the core is made in the form of reinforcing bars that fan out from the middle to the ends of the shell and are rigidly fixed in her, and the core is made of stressful concrete and base plates are fixed at the ends of the outer shell.

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