Summary
of the capabilities of the program PCSheetPileWall
View
on the user interface of the PCSheetPileWall program
(background picture can be changed)
With the aid of this program
the displacements and the force distribution of a sheet pile wall construction
can be calculated.
For stress checks both classic safety
coefficients and u.c. values according Eurocode
7 (EN 19971) are supported
The
figure below gives an impression of options present into the sheet
pile wall program.
Input section properties of sheet pile wall
Impression of the per
construction phase calculated moment, shear force and displacement
distributions.
Impression of the per construction
phase calculated water and total pressure distributions at the left and right side of the
sheet pile wall.
A further outline of the capabilities of the
program:
1. Levels
The
program has the capability to locate the top of the sheet pile wall, the place
of anchors, soil layers etcetera according two different systems of axes.
a.
Vertical axis pointing downwards.
The zero point is the top side of the sheet pile wall.
b.
Vertical axis pointing upwards. The
zero point is that of the national surveying system of levels.
2. Sheet pile wall
The
sheet pile wall in vertical direction can consists out of more than one section
with different values for the moment of inertia and elastic modulus.
The
default acting width of the sheet pile wall is 1 m. This
values can be decreased, by which graduated sheet pile walls can be
calculated for example.
Further
the program has a design option by which the length of a sheet pile wall from a
entered start length and with a certain step size by the program will be
enlarged automatically.
For
the input of the section properties of a sheet pile
wall these can be loaded from a standard library of commercial available sheet
pile sections included.
The
program has the ability to calculate the crosssection properties of a so called combi wall, existing of circular shaped tubes with
standard sheet pile sections in between.
At default the orientation of the sheet pile wall is vertical;
an option is present to give the sheet pile wall a certain inclination.
3. Surface and (ground) water levels
Dependent
of the choice made the surface level can have different shapes per construction
phase:
a.
Surface level is: horizontal and plain
b.
Surface level is:
sloping and plain
c.
Surface level is: bended; consisting of n bend points and n1 straight lines (Culmann method).
The
program has no preference with regard what will be entered al the left of right
side of the sheet pile wall.
The
excavations at the 3 figures above could have taken
place at the right side also.
Water
levels
From
the entered (ground) water level to below a hydrostatic build
up of water stresses takes place.
The
volume weight of the water is by default 9.81 kN/m^{3},
but this can be changed by the user when needed.
Per
entered soil layer, in relation to the hydrostatic stress distribution, an
extra under or over water pressure can be entered if necessary; provided that this option is switched on.
The
under and over pressures can be entered.
4. Vertical surcharges acting on the
surface level
Dependent
on the choice for the kind of surface level (see at preceding point 3)
different kinds of surcharges acting onto the surface level per construction
phase can be entered at the left and/or right side of
the sheet pile wall.
a.
Surface level: horizontal and plain or b. Surface
level: sloping and plain
 equal distributed surcharge
 trapezium shaped surcharge

Line load

Point load

Arbitrary shaped surcharge
c.
Surface level: bended; existing out of n bend points and n1 straight lines (Culmann method).

Line loads

Block loads
Further
at an arbitrary place onto the sheet pile wall a vertical line load can be
placed.
For
the calculation it is taken into account that this
vertical normal force has an influence on the size of the moment distribution
at the sheet pile wall (2^{e} order effects caused by the deflections
of the sheet pile wall).
5. Horizontal conditions
Per
construction phase the following horizontal acting
entities can be entered:
 anchors (or struts) with an anchor bulkhead when needed; prestressing and a maximum load capacity can be entered
 spring supports

fixed supports
 moments acting at a certain place onto the sheet pile wall
 under water concrete
 arbitrary shaped horizontal load acting onto the sheet pile
wall
6. Soil properties
Dependent
on the choice at various setups the strength and stiffness properties can be entered at a different way.
 the user does enter the friction angle and the angle of wall
friction per soil layer apart; the program does calculate the needed horizontal
active, neutral and passive effective stress coefficients (labda
values) from it
 the user does enter the horizontal active, neutral and
passive effective stress coefficients (labda values)
directly into the program.
When
the choice has been made for bended surface levels (Culmann) or
sloping plane surface levels than the second option is not possible however.
When
this is setup the number and properties of soil layers can be different for
each construction phase, otherwise the soil properties are equal for all
construction phases..
The
stiffness of the soil is reproduced with the aid of a spring constant This spring constant can have a linear distribution in size
over the thickness of a soil layer.
The
choice can be made for a linear course of the spring stiffness between the
active and passive displacement or a non
linear course (trilinear).
linear course of the spring stiffness
(single spring stiffness)
as an
alternative for the input of the spring constant the size of the
horizontal stretch can be entered also (a less common approach)
non constant value for the spring
stiffness; approximation by 3 straight lines
input
3
secans values (k_{1}, k_{2} and k_{3})
The values of 50% and 80% are the default values; these can be changed by the user however.
7. Input parameters
The
input of data into the program is divided into the next
parts.
8. Diaphragm walls (made of
concrete)
With
the entered properties of a concrete diaphragm wall the cracked bending
stiffness will be calculated by the program (a so called
MNK diagram).
Next
to the nonlinear behaviour of the soil the behaviour
of the diaphragm wall is nonlinear too therefore.
Input of properties of diaphragm wall
An example of a calculated MNK
diagram
Calculated cracked stiffness for a
certain construction phase of the diaphragm wall
9. Deterministic or probabilistic
calculation
For a deterministic calculation
the basic assumption is fixed values for the various input parameters.
For a probabilistic calculation
the basic assumption is a probability distribution for the various input
parameters (a specialty of PCSheetPileWall).
A deterministic approach is the usual method in
practice.
The probabilistic approach is a more advanced method,
which for three failure mechanism (soil collapse,
sheet pile wall collapse, collapse of anchor(s)) does calculate the probability
of failure. Furthermore
the influence per statistical parameter (stochastic variable) on the total
probability of failure will be calculated, from which follows which stochastic
variable is more or less important for the calculated probability of failure.
A probabilistic calculation should be
performed at a development phase that the design, with classical deterministic
design methods, has been fully thought trough only (it’s
a check afterwards). A probabilistic calculation can be
thought of as an automatic weighted sensitivity analyses.
In the program it’s possible
for a number of variables next to the expectation value to enter the standard
deviation for that variable; with which the variable has become a stochastic
variable. The stochastic variables have a standard normal probability
distribution; unless decided otherwise. For the SOIL properties the stochastic variable can have a NORMAL or
LOGNORMAL probability distribution. The advantage of the lognormal distribution
is that the regarding variable will have a value always larger than zero. The soil strength properties in a physical
sense cannot have negative values. For not to large
standard deviations the differences between the normal and lognormal
distribution are not so big.
The (ground) water levels at the left and right side
of the sheet pile wall are allowed to have a non normal probability distribution.
For this input variables there are nine different
probability distribution functions foreseen: Normal, Right truncated Normal,
Left truncated Normal, Exponential, Gumbel (type I extreme distribution for
largest values(, Type I extreme distribution for
smallest values, Weibull (type III extreme distribution for smallest values),
Uniform and LogNormal.
Knowledge of the backgrounds
of the probabilistic theory is very essential for the use of the program.
10. Earthquake loads according EN 19985
A general view of the program with some open windows: