Large pipe molds with external vibrators

Technical vibratory design and further development
of mold construction

Fig. 1 Vibration measurements on a large pipe mold.

Fig. 2 Finite element model of a large pipe mold left: presentation of a model mold, center: acceleration distribution during forced
vibration, right: stress distribution.

Fig. 3 Superimposition of two eigenforms of the pipe jacket
of similar geometry.

Fig. 4 CAD model of a conventional and a new pipe mold.

Fig. 5 Bending eigenforms of the pipe jacket at 79 Hz and 80 Hz.

Fig. 6 New pipe mold.

Fig. 7 Accelerations on the new mold jacket.

Fig. 8 DN 1200 jacking pipe manufactured with the new mold equipment.

The manufacture of precast concrete components in vibrating molds followed by in-mold curing is a time-tested production method that – thanks to the high surface quality and dimensional accuracy of the products manufactured in them – has gained a firm place in the precast industry. This method is also in popular use by manufacturers of large concrete and precast concrete pipes.

The vibration characteristics of large pipe molds with external vibrators had also been the focus of a research project of IFF Weimar e.V. that was completed in 2009. The project was supported by a research working group, of which the companies Wacker Neuson SE Munich, Wensauer Betonwerk GmbH Stockstadt, and Wolf & Co. GmbH Systemschalungen Hofheim were a part.

The objective of the optimization process was to obtain assured product quality with consistently good surfaces and cost reduction achieved with robust and low-cost concrete mixes. The method used for attaining these objectives is based...