| 摘要 |
For producing hollow concrete articles prestressed in the longitudinal and annular directions, in particular prestressed concrete pipes, use is made of a formwork mould (20) comprising an inner mould (21) and an outer mould (22). The inner mould (21) has between a rigid inner mould shell (25), for example made of steel, and an elastically deformable inner mould shell (27), for example made of rubber and serving as formwork for the hollow article, an inner pressure chamber (26) to which a hydraulic medium can be admitted. The outer mould (22) comprises a one-part rigid outer mould shell (28), for example made of steel, and an elastically deformable outer mould shell (30), for example made of rubber, serving as formwork for the hollow article, between which shells there is likewise formed an outer pressure chamber (29), to which a hydraulic medium can be admitted. For applying the longitudinal and annular prestressing to the hollow article, first of all the longitudinal reinforcement is stressed against the precompacted fresh concrete and then the annular reinforcement is stressed by radial expansion of the moulds.
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