RU2467075C2 - Method of rolling hot-rolled section reinforcement bars - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to construction reinforced concrete structures. To increase adhesion between reinforcements and concrete, load bearing capacity in compression, and fire resistance, rolled section reinforcements are rolled from tubular billets of alloyed steel "25Г2С", "30ХГ2С", "35ГС" intended for reinforced concrete structures, and reef-like ledges are rolled on their surface. Note here that said ledges are rolled in hot state by transverses rolling along left of right mono- or multifilar helix.

EFFECT: higher adhesion.

1 tbl, 2 dwg

Description

The present invention relates to building and reinforced concrete structures and their reinforcement.

Known hot-rolled rod reinforcement of a periodic profile, alloy steel 35GS, 25G2S, 30KHG2S. This reinforcement is provided with ridges (reefs) to increase its adhesion to concrete [1, p. 36], [2, p. 102], and the ridges are formed by rolling in the hot state in the longitudinal direction. Rigid reinforcement made of rolling elements and its use in monolithic structures are also known.

We take the well-known reinforcement for the prototype. The disadvantage of the prototype is that for joining the fittings you have to use manual welding, that is, the process is not technological. The process of manually joining reinforcing cages has an increased complexity, and automation of this process is complicated at the construction site. In winter conditions, manual welding significantly reduces the quality and reliability of the joints and, consequently, the entire structure. The reinforcement has excessive flexibility, which inhibits its use as rigid, to support the suspended formwork.

Known patent: "Method for the production of reinforcing steel" RU 2306989 C2. This patent describes a method for producing reinforcing steel, including multi-pass crimping of a strip in an oval-circle exhaust system with the formation of an oval profile with concave long sides in the finishing passage, and a profile with helical protrusions in the finishing passage, characterized in that the height ratio the oval to its width is 2.3 ... 2.5, in the finishing passage a profile is formed in the form of two symmetric arcs of the same circle with a radius equal to the radius at the apex of the oval, paired with each other in straight sections in the finishing passage, the strip is crimped with a hood of 1.3 ... 1.5.

The three figures clearly show that the cross section is not round and has straight sections where there are no protrusions. In the patent RU 2306989 carry out longitudinal rolling. The screw protrusions are interrupted on both sides by straight sections of the cross section, which weakens the work of the screw connection under tension.

Known patent: "Method for the production of reinforcing profiles" RU 2346991 C2. In the invention and in its formula, the ranges of changes in the chemical composition are given: carbon 0.14-0.26%; silicon 0.05-0.30%; manganese no more than 1.0%; chromium not more than 0.3%;

nickel no more than 0.3%; copper no more than 0.4%; harmful impurities: sulfur not more than 0.050%; phosphorus no more than 0.040%; nitrogen not more than 0.012%; iron is the rest. In the patent RU 234699 carry out longitudinal rolling.

The patent for utility model RU 6714040 U1 is known, which shows the effectiveness of using tubular reinforcing profiles.

An analysis of these sources of information shows that they are rolled in a longitudinal rolling mill.

In our case, the screw reinforcement is rolled into a tubular profile, and its ridges are rolled (rolled) in a hot state by transverse rolling along the right or left helical spiral of a single-pass or multi-pass.

It is obvious that the reliability and manufacturability of the joints can be easily improved when connecting the valves with nuts. Therefore, the ridges on the surface of the tubular workpieces should be rolled transversely by a helical spiral, and not randomly.

By increasing the external surface of the reinforcement in contact with concrete, we increase the adhesion of the reinforcement to concrete and, therefore, its anchoring. It is also obvious that with an increase in the diameter of the reinforcement, without increasing the cross-sectional area, the bearing capacity of the reinforcement increases when it is compressed and bent. Therefore, to improve the characteristics of reinforced concrete structures, reinforcement should be rolled from tubular billets with a cavity inside.

In addition, when a fire occurs and the temperature of the reinforcement rises to 600 ° С, the elastic modulus of steel reinforcement tends to zero and the structure collapses. If the reinforcement is made of a tubular profile, then it is easy to cool the reinforcement by pumping water through it and thereby eliminate the possibility of collapse of the structure in case of fire.

In addition, the implementation of the reinforcement of the tubular profile with ridges, knurled by the transverse knurling in the hot state along the right or left helical spiral of single-thread or multi-thread - expands its scope for anchor bolts of columns, machines and so on.

The technical task of the invention is to increase the adhesion of the reinforcement by increasing the surface of its contact with concrete, increase the bearing capacity of the reinforcement during compression, increase the adaptability of the joints and reliability of the joints of the reinforcement, increase the fire resistance of the structure and expand the scope.

The technical problem on the method of rolling reinforcing bars of the periodic profile of alloy steel 35GS, 25G2S, 30KHG2S for reinforced concrete structures and supplying it with ridges (reefs) is solved as follows.

The difference is that the reinforcement is rolled into a tubular profile. Moreover, the ridges on its surface are rolled (rolled) in hot state by transverse rolling along the right or left helical spiral of a single-start or multi-start.

Increasing the fire resistance of a reinforced concrete structure, in the event of a fire, is achieved by pumping water through a tubular reinforcement. The signal for pumping cooling water comes from temperature sensors inside the room.

In Fig.1 shows a hot-rolled tubular profile reinforcement of a periodic profile with a right or left helical spiral single or multiple; figure 2 is a cross section of it.

The hot-rolled tubular profile of the reinforcement 1 contains external ridges 2, which are rolled by hot rolling along the right or left helical spiral of a single-start or multi-start.

For example, when replacing bar reinforcement with a diameter of ⌀60 mm, equivalent in cross-sectional area to the tubular profile, the moment of inertia during bending increases by 16.56 times!

Diameter ⌀ mm Sectional area, cm ² Weight kg / m Inertia moment J _x , cm ⁴ Inertia radius i _x , cm Analogue 60 28.27 22.19 63.6 (100%) 1,5 New, tubular profile 180 × 5 27.4 21.5 1053.3 (1656%) 5.06

Comparison with the analogue [1, p.36] shows the following significant differences:

- hot-rolled reinforcement of a periodic profile alloyed steel 35GS, 25G2S, 30KHG2S is provided with ridges along the right or left helical spiral of a single-start or multi-start. The reinforcement is rolled into a tubular profile, and its ridges are rolled (rolled) by transverse rolling in a hot state;

- the adhesion of the reinforcement is increased in proportion to the increase in the surface of its contact with concrete, that is, ≈ 3 times;

- the bearing capacity of the reinforcement during compression is increased in proportion to the decrease in its flexibility, and the radius of inertia increased ≈ 3.37 times;

- the technological compatibility of the joints and the reliability of the joints of the reinforcement has been increased, since bolted joints with a high resource have been used [5, p.138];

- increased fire resistance of the structure and expanded the scope of the new tubular profile of the reinforcement with ridges, knurled by transverse knurling along the right or left helical spiral of single-pass or multi-start.

Information sources

1. Reinforced concrete structures. General course / V.N.Baikov, E.E.Sigalov. - M.: Stroyizdat, 1991, 767 p.

2. Reinforced concrete and stone structures: Textbook for construction specialties of universities / V. M. Bondarenko, V. G. Nazarenko, V. I. Rimshin; edited by V.M. Bondarenko - M .: Higher School, 2007, 887 p.

3. Large Encyclopedic Dictionary (BES). Editor-in-chief A.M. Prokhorov. - M .: Scientific publishing house "BIG RUSSIAN ENCYCLOPEDIA", 1998, 1456 p.

4. Nezhdanov K.K., Tumanov V.A., Nezhdanov A.K. Anchor device. Russian patent No. 2228405. Е02D 27/50, ЕВВ 1/38. Bull. No. 13. 05/10/2004.

5. Reference cranes: in 2 t.t. I. Characteristics of materials and loads. Fundamentals of calculation of cranes, their drives and metal structures // V.I. Braude, M.M. Gokhberg, I.E. Zvyagin and others: Ed. M.M. Gokhberg - M .: Engineering, 1988, 536 p.

Claims (1)

A method of rolling reinforcing bars of a periodic profile from alloy steel 25G2S, 30KHG2S, 35GS for reinforced concrete structures, including hot rolling of reinforcement from a tubular billet and rolling ridges on its surface in the form of reefs, while the ridges are rolled in hot state by transverse knurling on the right or left single or multiple helical spirals.

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