DE1128350B - Process for the manufacture of prestressed reinforced concrete pressure pipes and pressure lines - Google Patents

Description

Process for the manufacture of prestressed reinforced concrete pressure pipes and pressure lines The invention relates to a method zurr! Manufacture of prestressed Reinforced concrete pressure pipes and pressure lines consisting of an inner and outer reinforced concrete part exist and are produced in two steps one after the other. The inner reinforced concrete part is prestressed by winding reinforcement in a manner known per se, while the outer Reinforced concrete part is only provided with slack reinforcement. Both parts are according to the invention Interconnected by brackets, loops or the like.

Methods are known to produce reinforced concrete pipes in two sections, a sheet metal skin between the inner support tube and the outer protective concrete layer is arranged. This sheet metal skin serves as formwork for the preferably made of spun concrete to be produced inner support tube and is used at the same time as reinforcement of the centrifugal tube used. To stiffen the thin-walled sheet metal pipe is outside or inside a spiral reinforcement wound or welded on.

It is also known between the inner concrete pipe and the sheet metal jacket to leave a gap free, which is subsequently connected to a pressurized Intermediate layer, e.g. B. a plastic or liquid, rapidly hardening mass, is filled in order to thereby place the inner tube under a compressive bias. The sheet metal jacket in turn serves as formwork and at the same time as reinforcement. An outer concrete layer is also applied to protect this sheet metal pipe.

There is also known a method for producing longitudinally and transversely prestressed Concrete pipes, in a known manner after the manufacture of the core pipe on this a ring reinforcement under tension to generate a radial compressive prestress Applied in the concrete and the ring reinforcement protected by an outer concrete jacket will. However, there is no connection between the outer concrete jacket and the core pipe intended. The axial longitudinal prestress in the core tube is provided in this process the application of the outer protective jacket drained to zero and after application and hardening of the protective concrete is fully restored. Through the end flanges of the With the core tube, axial pressure is transferred to the outer protective concrete.

In the method according to the invention, no axial pressure is applied to the transferred to the outer concrete shell, but a radial pressure from the ring prestress in that the two successively concreted reinforced concrete parts by brackets, loops or the like. Are connected to each other. The one arranged in the known method Sheet metal skin between the inner core pipe and the concrete of the outer pipe casing separates the two concrete parts from each other and prevents an effect like them through the stirrup connection according to the invention of the prestressed inner with the non-prestressed, only slack reinforced outer concrete part is achieved.

In the method described above, it has a disadvantageous effect that no force-transmitting connection between the inner and the outer pipe part is available. This can easily cause cracks in the outer concrete shell, so that the prestressing steel reinforcement is not sufficiently protected against corrosion. aside from that the outer concrete jacket cannot absorb the internal pressure of the pipes or lines can also be used. These disadvantages can be overcome by the method according to the Avoid invention.

The inventive method assumes that the concrete wall of the reinforced concrete pipe in two roughly equally thick, ring-shaped parts one after the other will be produced. In this case, the inner ring produced first becomes more known per se Way prestressed by wrapping the reinforcement. The subsequently produced The outer ring, on the other hand, does not receive any prestressing reinforcement, but only slack reinforcement made of reinforcing steel, according to the invention by brackets, loops or the like. With the prestressed Concrete of the inner ring is connected.

As a result of the prestressing, the inner ring is not just concrete subject to shrinking, but also to creeping and therefore strives to his To reduce the diameter more than the non-prestressed, only subject to shrinkage outer ring. The production according to the invention causes the normally at Shrinkage and creep part of the tensile stress in the prestressed reinforcement that is lost and thus the compressive prestressing of the prestressed concrete in the inner ring through the Connection bracket is transferred to the outer reinforced concrete ring and this under a certain compressive stress. The Verbundwiikung thus become advantageous inner and outer ring together to absorb the pretensioning force and thus also of the pipe filling pressure.

In your method according to the invention, the prestressing steel, the is arranged in the middle of the finished pipe cross-section, through the outer, Reinforced concrete ring coming under compressive stress is adequately protected. Also will A saving in prestressing steel is achieved because the compressive stress in the outer part of the Pipe without the use of additional prestressing steel only by shrinking and creeping the inner concrete is effected.

Claims (1)

PATENT CLAIM: Process for the production of prestressed reinforced concrete pressure pipes and pressure lines, the concrete wall of which consists of two roughly equally thick, ring-shaped Parts consists of which the inner part is made first, with a wire wrapping is provided and prestressed, characterized in that the slack reinforcement of the outer annular part by brackets, loops or the like with the prestressed Concrete of the inner annular part is connected. Considered publications: German patent specification NT. 585 579; German Auslegeschrift No. 1039 909; German Auslegeschrift M 25131-V / 80 a (published on March 22, 1956).