Lowerable Manholes
In order to reduce costs for expensive vertical sheeting work and water drainage during manhole construction, the sinking of lowerable manholes is a very economical alternative to local concrete construction or pre-fabricated parts. The manhole is set on the ground and slides, during removal of the core earth in the construction site, evenly via its own weight into the building ground.
Manhole Bottom
As a rule, several manhole parts are set upon each other, in order to reach a greater depth. For this, after the depth of the site as been reached, the manhole bottom is made in the required thickness, in ground water with underwater concrete, otherwise with conventional concrete. After the concrete hardens, the manhole is pumped out. If pressurised or pre-loaded ground water is present, additional sealing measures between the manhole bottom and the underside of the manhole must be taken.
