Calculation and Designing of Reinforced-Concrete Non-Pressure Pipes with Inner Lining
This article presents the results in investigations of the load-carrying ability of reinforced-concrete non-pressure pipes with the inner lining intended to protect concrete against corrosion. The lining (covers) are mounted as a stay-in-place formwork when manufacturing the pipes. To manufacture the covers, polyethylene sheets with the thickness of 3-5 mm are used. To be fastened in the pipe wall concrete, the linings are provided with special anchoring elements. Two lining types are considered: 1 – with anchoring elements in the form of solid longitudinal ribs; 2 – with anchoring elements distributed equidistantly over the shell surface.
The investigations have been performed by the numerical simulation method using a volumetric finite-element model. The load was applied according to a trilinear pattern which is used to test the pipes for strength (including that specified in ЕN 1916). The calculation was performed by the iteration method taking into account the physical non-linearity of concrete.
It has been determined that the load-carrying ability of the pipes with the first-type protective linings is lower than that of the pipes with the second-type linings. The maximum (up to 25%) reduction of the load-carrying ability is observed in the pipes reinforced with a single cylindrical cage.
To protect the interior faces of reinforced-concrete non-pressure pipes, it is recommended to use the lining covers with the V-type discrete anchoring members ensuring the reliable mechanical fastening of the linings in the pipe wall concrete. This type of the anchoring elements causes practically no effect upon the load-carrying ability of the pipes.
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