Carrying capacity — Minimum foundation depth

The depth of the Pleistocene sand often indicates, but not always, what the minimum length of foundation piles will be. The province of Utrecht has produced a map showing the suitability of the subsurface for ‘traditional building’. This means: structures made of stone or concrete with a foundation on steel or piles, and infrastructure (roads) without pile foundation. The starting point for mapping is that the greater the investment in the foundation, and/or the higher the potential management costs, the less appropriate a location is considered. The map of the foundation depth gives an indication of the costs for a foundation. This also takes into account shallower layers of sand. Currently no national picture of the minimum foundation depth as implemented for the Province of Utrecht and North Holland is available. However, a simplified map is available that was made by TNO for the television program clock house. This is based on the depth of the top of the pleistocene formations. There are 3 classes defined; class 0 = not pile (where the top of the pleistocene formations reaches ground level) class 1 = short pile piles (where the top of the pleistocene formations lies between ground level and 5 m deep) class 2 = long pile piles (where the top of the pleistocene formations is deeper than 5 m) The map is based on the depth of the top of the pleistocene formations. In addition, it also used the surface geology map from 2006 to get a better picture of the river area (particularly the distribution of the Formation of Echteld). (For information about this card, please contact Jan Gunnink, [email protected])