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Tension Piles model (EC7-NL)
no skin friction is calculated in layers in which Apply tension is set to False
no skin friction is calculated in peat layers (αt = 0)
The weight of all soil layers with no friction is taken into account when determining effective
stresses and total soil weight. This also includes soil layers above the pile head level. The
skin friction zone can be entered at any level.
19.8.4
Non-rigid/rigid
DR
AF
T
One restriction when creating schematics is that for each calculation only (parts of) structures
that can be considered either as "completely rigid" or as "completely non-rigid" may be included a single schematic. It follows that, for structures that are partly "non-rigid" and partly
"rigid" (for example, a building with a rigid core), the user must execute at least two calculations, one for the non-rigid part and one for the rigid part. Moreover, if the structure consists
of several different parts that can be considered as rigid, the user must execute a calculation
for each part. Figure 19.4 includes an example of division into sub-calculations.
1
2
Partial calculation 1: piles for rigid part of structure
Partial calculation 2: piles for non-rigid part of structure
Figure 19.4: Partial calculations for a mixed rigidity structure
For the definition of rigid/non-rigid, see NEN 9997-1+C1:2012 art. 7.6.1.1(c).
19.8.5
Combination of superimposed load and excavation
If a combination of a superimposed load (or surcharge) and excavation occurs, the following
restrictions apply when calculating the bearing capacity.
When designing building pits, the effect of excavations is taken into account. These excavations have limited dimensions. Due to distribution of stresses in the sub-soil, the effect of
the limited excavation on the CPT value is less than for an unlimited excavation. This effect
is taken into account while determining the effect of the excavation. This means that one
excavation level is determined for the building pit and thereby for all the piles.
When using tension piles in a design that will be executed in phases, both the phase with
maximum tension load and the phase with the minimum tension load should be considered
using two separate calculations. The sequence of phases (which can be defined in the Project
Deltares
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