Process for the manufacture of a shaft bottom

A process for manufacturing a shaft bottom part made of concrete and having an individual chute of a predetermined shape, wherein said process comprises the steps of:

• providing a plurality of prefabricated moulded pieces (9, 14) having a linear longitudinal extension and a plurality of prefabricated moulded pieces (10, 15) having an arc-shaped longitudinal extension;
• selecting two or more moulded pieces (9, 10, 14, 15) out of said plurality of prefabricated moulded pieces (9, 10, 14, 15);
• cutting and trimming the selected moulded pieces (9, 10, 14, 15) to adapt the selected moulded pieces (9, 10, 14, 15) to the predetermined shape of the chute,
• wherein cutting the selected moulded pieces (9, 10, 14, 15) comprises cutting the selected moulded pieces (9, 10, 14, 15) to a required length according to the predetermined shape of the chute and trimming the selected moulded pieces (9, 10, 14, 15) comprises trimming the selected moulded pieces (9, 10, 14, 15) in height according to the predetermined shape of the chute and/or trimming the selected moulded pieces (9, 10, 14, 15) at the face side of the selected moulded pieces (9, 10, 14, 15) for fitting together according to the predetermined shape of the chute;
• assembling the selected moulded pieces (9, 10, 14, 15) for forming a moulded body (8) according to the individual chute geometry, said moulded body (8, 18) forming the negative mould of the chute;
• inserting the moulded body (8, 18) into a bottom mould (1) comprising a mould bottom (3) and a mantle (2);
• filling a mixture of concrete into the bottom mould (1);
• and
• removing the moulded body (8, 18) from the shaft bottom after or simultaneously with stripping the formwork from the shaft bottom.