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S.P.W. (Sheet Piles Walls)I

2013 Geostru Software

S.P.W. (Sheet Piles Walls)

Parte I SPW 1

................................................................................................................................... 11 Introduction

Parte II Menu 3

................................................................................................................................... 41 File Menu

.......................................................................................................................................................... 5New

................................................................................................................................... 72 Edit Menu

................................................................................................................................... 73 View Menu

................................................................................................................................... 94 Tools Menu

................................................................................................................................... 105 Archives Menu

................................................................................................................................... 106 Data Menu

................................................................................................................................... 117 Calculation Menu

................................................................................................................................... 138 Export Menu

................................................................................................................................... 139 Preferences Menu

................................................................................................................................... 1410 Help Menu

Parte III Archives 14

................................................................................................................................... 141 Material archive

................................................................................................................................... 182 Sections Archive

................................................................................................................................... 253 Fastening anchors

................................................................................................................................... 274 Reinforcements archive

Parte IV Data Analysis 30

................................................................................................................................... 301 General data

................................................................................................................................... 322 Ground geometry

................................................................................................................................... 383 Structure

................................................................................................................................... 404 Stratifications

................................................................................................................................... 435 Graundwater

................................................................................................................................... 466 Anchoring System

................................................................................................................................... 487 Supports

................................................................................................................................... 498 Loads

................................................................................................................................... 539 Forces Applied

................................................................................................................................... 5610 Pressures assigned

................................................................................................................................... 5811 Modulus of subgrade reaction assigned

................................................................................................................................... 6312 Boundary Conditions

Parte V Analysis 65

................................................................................................................................... 651 Analysis

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S.P.W. (Sheet Piles Walls)II


.......................................................................................................................................................... 67Interference betwee n the phases

................................................................................................................................... 672 Pressures diagrams

................................................................................................................................... 693 Solicitations diagrams

................................................................................................................................... 694 Results of the structural ana lysis

................................................................................................................................... 705 Fastening area of the anchors

Parte VI Export report 71

................................................................................................................................... 711 RTF Export

................................................................................................................................... 732 Export DXF

Parte VII Material take off 74

Parte VIII Global stability 74

Parte IX Theory 75

................................................................................................................................... 751 FEM Method

.......................................................................................................................................................... 78Modulus Ks

................................................................................................................................... 782 LEM Method

................................................................................................................................... 803 Limit load of the anchors

Parte X Contacts 82

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SPW 1


1 SPW

1.1 Introduction

The bulkheads are made up of a relatively thin vertical structure, toothedto the ground up to a certain depth underneath the dredge level, so as toobtain a support solid enough to oppose the thrusts of the ground, ofwater and of possible overloads. This type of supporting structure can bemade up of prefabricated and embedded sheet piles, drilled piles c lose toeach other and diaphragm in reinforced concrete, and sometimes also ofreinforced concrete panels (reinforced concrete partitions).

In the following figure is reported, by way of an example, the diagram ofan overhanging bulkhead built using reinforced concrete piles.

Figure: Diagram of a bulkhead built by placing reinforced concrete pilesclose to each other

The most widely used calculation methods are the following:

Limit Equilibrium

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S.P.W. (Sheet Piles Walls)2


Finite-elements

While the limit equilibrium method is based on considerations which are onlyand exclusively of static nature, for the finite-elements method

considerations also based on the congruence of the deformations (the FEMmethod is thus a more rational method). The mentioned methods have agrowing complexity both from the numerical point of view and in terms ofpreliminary operations for the calculation. In fact, while for the LEM methodit is necessary to know the classical properties of the earth material (innerangle of friction, etc.) for the FEM method it is also necessary to estimatethe modulus of subgrade reaction of the ground and characterizer itspossible non-linear behaviour. The SPW programme allows carrying out theanalysis of overhanging or bulkheads con anchors, according to the twoalready mentioned calculation methods.

GENERAL FEATURES (As regards the software input)

The models it is possible to analyze with Bulkheads are representative of mostof the problems met in current practice. From a general point of view (we willgo into details in the following sections), the main features of the input are thefollowing:

Material making up the bulkhead (Materials archive);

Sections of the vertical structure (Sections archive);

Fastening stringcourses;

Anchors (Anchors archive);

Treatment of the sett ings related to the reinforcement of the structure

(Reinforcements options);

Calculation methods (Limit equilibrium, Finite-elements);

Soil model geometry (treatable both in terms of coordinates of vertices and in

terms of angles and distances);

Property of the soil (it is possible to define different soil properties an

consider different stratifications);

It is possible to consider the presence of the groundwater, also for possible

filtration studies and consequently siphoning checks;

Acting loads, treated both by means of concentred loads and loads divided

by stripes, lines or uniform;

Analysis phases. It is possible to define different scenarios of cementation of

the structure, referring to analysis phases which can change by stratigraphy,

materials features, imposed restrictions, loads, etc.

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SPW 3


GENERAL FEATURES (As regards the calculation phase)

Analysis realizable with the limit equilibrium method and the finite-elements

method;

Analysis realizable for more load combinations and for different analysis

phases;

Calculation of the pressures due to the presence of the groundwater, outer

loads, etc.

Preparation of a service programme for the analysis of the stresses on a

schematizing continuous beam or the head beams or the anchoring beam;

Realization of a metrical computation;

Global stability analysis (by means of the following methods: Fellenius, Bishop,

Janbu, Bell, Sarma);

Project of the bulkhead sections;

Determination of the flow grid and calculation of the filtration flow rate;

GENERAL FEATURES (As regards the output phase)

Visualization of the diagrams relevant to the horizontal pressures;

Results of the bulkhead structural analysis in terms of checks or section

project;

Generation of technical reports (including theoretical outlines) select ive wit

respect to the subjects to be printed (it is possible to print theoretical

outlines, input data, calculation output).

Generation of complete graphic printouts in which are defined the measures,

quantities and shaping of the reinforcements resulting from the calculation.

2 Menu

Menu

File Menu

Edit Menu

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View Menu

Data Menu

Loads Menu

Structure Menu

Analysis MenuExport Menu

Preferences Menu

Help Menu

2.1 File Menu

New:

Creates file(s) for a new project. (Function is also available from the Standardtoolbar)

Open:

Opens file(s) for a previously created project (stored with STA extension).(Function is also available from the Standard toolbar)

Save:

Save file(s) for the currently open project, replacing any previous version(Function is also available from the Standard toolbar).

Save As:

Save file(s) for the currently open project (with SPW extension) under the nameand in the folder, to be entered in a subsequent dialogue window. This creates a

new file with that name. If the file already exists the user is asked to confirm thatit should be overwritten.

Print Setup:

Presents standard windows printer select & set up dialogue window.

PrintPreview:

Presents the preview window with dialog window for the control of the printedimage.

Recent Projects:

Recalls the names of the last open file.

Exit:

Program exit.

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Menu 5


2.1.1 New

In this software it is possible to create a new file with the tutorial. When youclick on the command "New" opens the following window:

Figure: Environment for the management of a new model.

Project:

Identifies a synthetic description of the project to be executed. Itincludes the possibility to print this data in course of exportation in rtfformat. To do this you must only tick off the square (with a red edge anda diagonal line) situated on the right side of the text box containing thedescription of the project;

Date:

This is the date which will appear in the calculation report;

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Regulations:

It is possible to select the regulations connected to the geotechnicalchecks (GEO Regulations) or the ones connected to the structural checks(STRU Regulations). For each category of check, the following choices

are possible:

GEO Regulations:

Eurocode 8

STRU Regulations:

Eurocode

Calculation of pressures:

In this group of data are defined the theories which can be used for thecalculation of the active thrust coefficient, for the passive thrustcoefficient and for the limit state coefficient (active or passive) indynamic conditions. In particular, the following options are possible:

Active pressures:

It is possible to use the Coulombs theory, Muller-Breslaus theory or Caquot-

Krisels theory;

Passive pressures:

It is possible to use the Coulombs theory, Muller-Breslaus theory or Caquot-

Krisels theory;

Seism ic pressures:

It is possible to use the Mononobe-Okabes theory.

Calculation model:It is possible to select a priori the calculation approach for thedetermination of the stresses and displacements. In particular, it ispossible to choose the LEM method (Limit Equilibrium Method) or the FEMmethod (Finite Elements Method).

Geometry:

In this group of data are set the data sizes with which to initialize the model.In particular:Depth of excavation:

it is expressed in me is the part that remains above ground of thebulkhead after the excavation;

Inclination of the land upstream and downstream:in degrees, they affect the value of coefficients of active and passive

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Menu 7


thrust;

Section:from among the sections defined in the Archive sections. In this firstphase of the project, the chosen section is extended to the whole height

of the excavation, but then it is possible to differentiate sectionsthroughout the height of excavat ion, the different types of sec tion.

2.2 Edit Menu

The Edit Menu presents those functions relative to editing data for the currently openproject.

Undo:

Cancels the last amendment restoring the situation as before the change.(Function is also available from the Standard toolbar)The function also operates in the graphic worksheet allowing backtracking througha number of actions.

Redo:

Reapplies the actions undone by the undo function.

Copy:

Copies to the clipboard the selected area of the active window. (Funct ion is alsoavailable from the Standard toolbar). This function is particularly useful to copybitmaps of images in the various phases of computation to a preferred editor(Word, Works etc.)

Paste:

Pastes the clipboard in the worksheet.

2.3 View Menu

Zoom all: Allows viewing all the graphic objects present in the window, resizing the

view of the work window so that all the graphic objects can be contained;

Zoom +: Allows the scaling up of the graphic objects so as to make them bigger at

the users sight;

Zoom -: Allows the scaling up of the graphic objects so as to make them smaller at

the users sight;

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Zoom window: Allows enlarging a part of the work window previously selected

through a selection box;

Dynamic zoom: Allows enlarging or reducing in size the graphic objects contained

in the drawing area through a dragging operation holding the left button of the

mouse pressed;

Move: Allows the displacement en masse (including the reference system) of the

graphic objects contained in the drawing area;

Grid: Thegrid menu (made up in turn of other submenus) is used for the

management of the drawing grid. In particular:

Visible grid: Allows viewing or not viewing the drawing grid (represented by lines

mutually orthogonal with constant and fixed spacing)

Interval x/z: Allows sett ing the spacing of the grid lines both in the vertical

direction (z) and in the horizontal direction (x). The reference unit for the

definition of the spacing is the same as the one used for the definition of the

model geometry.

Colour: Allows the setting of the colour of the grid lines;

View:

the view menu allows selecting only some elements to be displayed. In

particular:

Section z-Stratigraphy: Allows viewing, in vertical section (z direction) the model

stratigraphy;

Section y-Structure: Allows viewing the structure, and in this specific instance

the executive details relevant to the section of the bulkhead and to the longitudinal

reinforcement of the piles (or possibly of the partitions);

Section z-Section y: Allows viewing all the elements, both the reinforcement and

the stratigraphic model;

Reference axes:

Allows viewing or not viewing the reference system form which the model geometry

is defined. Theorigin of the reference sys tem always coincides with the hea d

of the bulkhea d.

Stratigraphic description:

Allows viewing the description of the stratigraphy, which is made in terms of Name

of the material making up the layer, weight of the volume unit and angle of inner

friction of the ground.

Selection grip:

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Menu 9


Allows setting the dimension of the selection grip.

2.4 Tools Menu

Selection:

Allows the selection of the graphic objects though the grips (points whichdefine the graphic object);

Text:

Allows entering texts. It is possible to set various properties for the texts,such as fonts, sizes, etc.;

Line:

Allows drawing a line, selecting the extreme points of the line. The selectionof the extreme points is made by double-c licking on the drawing area;

Rectangle:

Allows drawing a rectangle, select ing two opposed vertices of this latter. Theselection of the extreme points is made by double-clicking on the drawingarea;

Circle:

Allows drawing a circle on the work area; with the first click, the position ofthe centre is defined, while with the second click the width of the radius isdefined;

Polygon:

Allows drawing a polygon, assigning its vertices with various clicks on themouse;

Foreground:

Allows placing the selected objects in the foreground of the display;

Background:

Moves the selected objects to the background of the display;

Distance:

Measures the distance between two points situated on the drawing area. Thedistance is measured clicking once on the starting point and holding the leftbutton of the mouse pressed dragging the cursor to the second point;

Project properties:

Allows defining the general settings connected to the project graphics;

Move drawings:

Allows changing the position of the drawings as to the fixed reference system(x-z);

Reposition drawings layout:

Resets the position of the drawing area and of the graphic objectscontained in it, restoring the default conditions.

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2.5 Archives Menu

Materials Archive

Window which contains the properties of structural materials (steel and concrete);

Sections Archive

Window which contains the properties of the sections that make up the bulkhead;

Anchors Archive

Window which contains the properties of the anchors;

Reinforcement Options

Window which contains all the options for reinforcement;

2.6 Data Menu

Each control of this menu is described detail in the Calculation Data chapter.

General data

Displays the window with the data initialized with the new project;

Limit equilibrium method:

Sets the limit equilibrium method as the current analysis method;

Finished elements method:

Sets the finished elements method as the current analysis method;

Ground geometry:

Opens the window from which it is possible to enter the data relevant to the

topographic profile of the ground;

Structure:


structural composition of the bulkhead;

Stratifications:


different stratifications of the ground;

Groundwater:


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Menu 11


groundwater and the data relevant to the possible analyses involving the

presence of the groundwater;

Anchoring system:

Opens the window from which it is possible to enter the data relevant to

possible fastening anchors;

Supports:


supports (e.g. supporting struts);

Loads:

Opens the window from which it is possible to enter the distributed loads;

Forces applied:

Opens the window from which it is possible to enter the forces applied;

Pressures assigned:

Opens the window from which it is possible to enter possible boundary

conditions on the distribution of pressures assigned by the user;

Modulus of subgrade reaction assigned:

Opens the window from which it is possible to impose (at given round levels)

the value of the modulus of subgrade reaction of the ground;

Boundary conditions:

Opens the window from which it is possible to impose boundary conditions

(displacements, rotations, etc.);

Add phase:

Allows entering an analysis phase;

Cancel phase:

Allows cancelling the current analysis phase;

2.7 Calculation Menu

Bulkhead analysis:

Starts the analysis procedure, opening the window starting from which it is

possible to define the load combinations and consequently to carry out the

necessary checks;

Cancel analysis:

Sets to zero the previously executed analysis;

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Combination:

Allows selecting the combination with regard to which to view the output;

Pressures diagram:

The Pressures Diagram menu (made up in turn of other submenus) is used for

the management of the display relevant to the results of the calculation. In

particular:

Ground pressures:

Allows viewing the diagram relevant to the pressures of the ground on

the bulkhead;

Seismic pressures:

Allows viewing the diagram relevant to the increase in the seismic

pressures;

Neutral pressures (earth pressures):

In case there is a groundwater, allows viewing the diagram of the

neutral pressures;

Pressures of distributed loads:

Allows managing the display of the diagram relevant to the pressures

generated by the presence of overloads;

Load lines pressures:

Allows managing the display of the diagram relevant to the pressures

generated by the presence of load lines;

FEM pressures:

Allows viewing the pressures diagram in the framework of the use of

the FEM method;

Pressures view value:

Allows viewing, for all the diagram categories seen before, the value of

the pressures on changing in depth;

Solicitations diagram:

Allows the opening of a window through which it is possible to view the

results of the analysis of the solicitat ions, such as diagram of

displacements, moment and shear;

Results of the structural analysis

Allows the opening of a window through which it is possible to view the results

of the structural calculation, in terms of reinforcement, extreme deformations,

results of the checking etc.

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Menu 13


Anchors fastening zone:

Allows viewing the stable ground area inside of which it is suggested (and,

obviously, necessary) to fasten possible anchors;

Flow grid

Allows viewing the flow grid and consequently the equipotential lines and the

flowlines.

Quantity survey (MTO):

Allows the opening of the window relevant to the material take off.

Connecting beam:

Allows the opening of a useful service programme for the analysis of a

continuous beam, schematizing the head beam or the fastening beam.

Global stability:

Starts the procedure for the global stability analysis of the model.

2.8 Export Menu

RTF Export

Display the report of the analysis in RTF format. The internal editor of text has gotthe commands necessary to modify the report, to save and to print.

DXF Export

Exports in DXF format as much as is displayed to video (strat igraphy/reinforcement).

BMP Export

Exports in BMP format as much as is displayed to video

n.b. All export files have the same main file name and extension that identifies

them,in information "? " will be given directions on the paths and names .

2.9 Preferences Menu

Options

Displays the dialogue window for the setting of the parameters relevant to thework area and to the output.

Work area:

It is possible to customize the colours of the background and of the lines, as well

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as the relevant thickness and the tolerance of the cursor.

Outputs:

contrary, it is possible to modify the margins of the sheet, the colour of the

background and of the heading of the tables, then inclusion of the calculationtheory in the report and the heading.

Company data:

entering the data relevant to the company.

Company data:

Allows setting the parameters relevant to the saving of the model (e.g. how oftento save the file).

2.10 Help Menu

Table of contents:

Displays the table of contents and the summary of the online guide.

Registration:

Displays the window for the registration of the programme which appears at the

first start of the programme for the registration by means of the software or when

it works in the demo version.

Version and control of updates:

Displays the software version in use.

Import files from pocket:

Allows importing files generated with software for pocket PC.

3 Archives

3.1 Material archiveTo this unique materials archive refer all the sections of the structuralelements planned in the programme. Each of the data appearing in the tablesby default can be changed (also for the considerat ions developedafterwards) and do not constitute any vehicle for the designer as the onlyperson responsible for the values assumed.

NB: In order to delete any kind of conglomerate amongst the onesexpounded in the table, you only have to delete all the characters

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Archives 15


present in the box of Concrete Class column.

The environment through which it is possible to mange the materials archiveis the following:

Figure: Window for the management of the structural materials

Conglomerates Data

Concrete Class

The conglomerate class must have a standard designation included amongst

the indicated ones: C20/25; C25/30; C28/35; C35/45 etc., defined on the basis

of the characteristic strength, respectively cylindrical fck and o Rck cubes

(expressed in MPa).

fck, cubes [MPa]

This is the characteristic compression strength Rck on cubes to refer to in the

course of the project.

Ecm [MPa]

This is an elastic module of the concrete to be used in the course of the

planning Ecm = 220000 [(fck+8)/10]0.3

fck [MPa]

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This is the characteristic cylindrical compression strength which on the other

hand appears as the first term in the standard designation of the class. In

order to pass from the c ubic to the cylindrical strength, the expression to be

used is fck = 0.83 Rck

Fcd [MPa]

This is the calculation strength of the conglomerate corresponding toc c

fck /

cwhere

ccis the reduct ion factor for long-lasting strengths and as a ruler

corresponds to 0.85 and c = 1.50 is the partial coefficient of concrete. For

level elements (slabs, walls, etc.) with thicknesses lower than 5 cm and

realized in brickwork the fcd value must be reduced by 20%.

fctd [MPa]

This is the calculation tensile strength equal to: fc tk / c = 0.7 fctm / c

fctm [MPa]

This is the average tensile strength equal to 0.3fck2/3

Poisson

The value of the Poisson ration can vary from 0 (cracked concrete) to 0.2

(non-cracked concrete). The programme uses this coefficient for the

calculation of the tangential modulus of elasticity G = 0.50 Ecm (1+m)

AlfaT

Thermal expansion coefficient.

P.S.[KN/m]

Unit weight of reinforced concrete. It is used by the programme for the

calculation of the weights peculiar to the structural elements.

Steels data by bars

Steel Type for: reinforced concrete structures, a single steel type can be used.

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Archives 17


Es [MPa]

Modulus of elasticity of steel.

fyk [MPa]

Characteristic yield stress assumed in the course of the project corresponding

to the rated one 450 N/mm.

fyd [MPa]

Calculation yield stress assumed in the course of the project corresponding to

fyk / s where s is the partial coefficient of steel.

ftk [MPa]

Characteristic breaking stress assumed in the course of the project corresponding

to the rated one (540 MPa).

Ftd [MPa]

Calculation breaking stress assumed in the course of the project. It can be

assumed as equal to fyd (null work-hardening) or to fyd k where k = ft / fy.

This ratio cannot be lower than 1.15 or higher than 1.35. Prudentially, k =

1.15can be assumed

ep_tk

Characteristic unit strain at failure. Its value cannot be lower than 0.075.

epd_ult

Ultimate calculation deformation corresponding toud

= 0.9uk

1 2 init.

Steel-concrete adherence coefficient on the first application of the load. It is

used by the programme in the checking of the cracks in the infrequent

operating combinations (SLE, limit operativeness state).

1 2 init.

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Steel-concrete adherence coefficient for long-lasting loads. It is used by the

programme in the checking of the opening of the cracks in the frequent and

quasi-permanent operating combination (SLE). Limit operativeness states

parameters (Opening of cracks Normal strains).

Limit operativeness states parameters (Opening of cracks Normal

strains).

Opening of cracks

In this column are reported the limit values relevant to the opening of cracks

fixed according to the limit state and to the fixed environmental conditions

(these latter must be indicated in the General Data window).

S.Cls [aliq. fck]

Limit strain of the operating concrete expressed as a rate of the characteristic

breaking stress of concrete.

S.Fe [aliq. fyk]

Limit strain of the operating steel expressed as a rate of the characteristic

breaking stress of steel.

3.2 Sections Archive

In this archive are defined the sections that constitue the structure of thebulkhead (piles or diaphragm). The environment through which it is possible tomange the sections archive is the following:

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Archives 19


Figure: Environment for the management of the sections

Through this window you can make many operations on sections. In the first instanceyou can add or delete sections (with buttons that are high in the central part of the "+"and "-"). For the correct definition of a section you must enter the following data:

Section:

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This datum defines the type of the section to add to the archive. You can choose

from the following options:

C ircular ba rs - This is a circular cross section with radially spread armor consists

of steel bars classics.

Figure: Model of the section Circular bars

For this category of sections the data to be included, in addition to those related

to managed reinforcement in the Options are as follows:

o Name - Name identification section;

o Concrete - Select from the materials archive;

o Steel - Select from the materials archive;

o Diameter - Expressed in m;

o Arrangement(a single row or quincunx);

o Wheelbase in 2 directions (the second direction is required only if the layout is

kind of a quincunx) - expressed in m

o

Circular tubular - This is a hollow section, whose central part is formed by aprofiled steel tubular circular section:

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Archives 21


Figure: Model of the section Circular tubula r

For this category of sect ions the data to be included, in addition to those related


o Name- Name identification section;

o Concrete- Select from the materials archive;

o Steel- Select from the materials archive;

o Diameter of the section in concrete- Expressed in m;

o Exterior Diameter of tubular section- Expressed in mm;

o Thickness of the tube- Expressed in mm;


o Wheelbase in 2 directions(the second direction is required only if the layout is


o Circular HE shape - This is a hollow section, whose central part is formed by a

profiled steel HE shape:

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Figure: Model of section Circular HE shap e






o Diameterof the section in concrete - Expressed in m;

o Base shape- Expressed in mm;

o Height shape- Expressed in mm;

o Thicknessof the sheet web (Sa) - Expressed in mm;

o Thicknessof plate wing (Se) - Expressed in mm;


o Wheelbasein 2 directions (the second direction is required only if the layout is


o Circular box sha pe - This is a hollow section, whose central part is formed by a

profiled steel to box rectangular section:

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Archives 23


Figure: Model of section Circular box shape



o

Name- Name identification section;o Concrete- Select from the materials archive;



o Base shape- Expressed in mm;

o Height shape- Expressed in mm;

o Thicknessof the sheet box - Expressed in mm;


o Wheelbasein 2 directions (the second direction is required only if the layout is

kind of a quincunx) - expressed in m;

o Rectangular- This is a rectangular section in reinforced concrete:

Figure: Model of section Rectangular





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o Base of the section (Bx);

o Height of the section (Hz);

For all types of sections is necessary to define the alignment of the reference system.This is the location that the general sect ion should take in the context of structuralbulkhead.NB The reference system of coordinates is such that the z-axis coincides with thevertical direction, the x-axis with the horizontal axis in terms of design and y-axisorthogonal to both. From this derives the name Bx Hz and for the geometric data of the

rectangular section.

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3.3 Fastening anchors

The fastening anchors are necessary works to integrate the resources of structural andgeotechnical strength of the bulkhead. The software allows managing an archive for thefastening anchors. A significant representation albeit schematic of the quantities

which characterize a fastening anchor is represented in the following figure:

Figure: Graphic schematization of an anchor

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In the figure, following symbols can be recognized:

Anchor free length (LL);

Bulb length (LB);

Bulb d

Diameter (DB);

Anchor section area (A);

Besides, the zones where the anchor is fastened to the bulkhead (on the upper leftside) and the zones where the anchor is fastened to the ground can be recognized aswell. Taking into account the previous figure, the environment which allows managingthe anchors archive is the following:

Figure: Environment for the management of the anchors archive

As it can be observed, the data to be entered in order to correctly characterize

an anchor are the following:

No:

This identifies the number of the anchor in the archive (ascending order number);

Description

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Archives 27


His is the name through which the anchor is identified inside the archive;

Reinforcement area

This is the area of the anchor section which reacts to traction (steel part of the

anchor), expressed in cm (Order of magnitude = 15/20 cm);

Hole diameter

This is the diameter of the hole made for the insertion of the anchor, expressed in

m (Order of magnitude = 0.2/0.8 m);

Free length

This is the length of the anchor reacting to traction (steel part of the anchor),expressed in m (Order of magnitude = 10 m);

Bulb length

This is the length of the part of anchor which reacts by friction with the earth

(upon which rely the strength resources connected to friction and adhesion with

the earth). With regard to the previous figure, it is the final part of the anchor. It

is expressed in m.

Materials

Materials to be associated to the type of anchor are derived from Materials Archive

Colour

It is also possible to insert the colour which identifies the anchor in the model.

NB: for geotechnical and structural checks on the anchor, please refer to

theoretical Outlines (Anchors limit load).

3.4 Reinforcements archive

The options relevant to the reinforcements refer to the bulkhead structuralplanning.

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Figure: Environment for the management of the reinforcement options.

As regards this section, the data to be entered are the following:

PILES:

These data are used for the planning and structural checks carried out onbulkheads made up of piles of reinforced concrete:

Diameter of the longitudinal bars:

Diameter of the tubular rods expressed in mm (Order of magnitude = 12/26mm);

Length of the hooks of the longitudinal bars:

Expressed in cm (Order of magnitude = 50/150 cm);

Maximum length of the longitudinal bars:


Concrete cover:Expressed in cm (Order of magnitude = 4/6 cm);

Clamping diameter:

Expressed in mm (Order of magnitude = 8/10 mm);

Minimum pitch of the clamps:

Expressed in cm (Usually imposed by the regulations, in any case Order ofmagnitude = 15/25 cm);

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Archives 29


[Tubular rods] Anchored stretch of pile:

This is the length which defines how much a tubular rod is toothed on thehead, expressed in cm (in any case, less than the height of the headbeam);

[Tubular rods] - Diameter of the U-bolt bars:

Expressed in mm;

PARTITIONS:

These data are used for the planning and structural checks carried out onbulkheads made up of partitions of reinforced concrete:


Expressed in mm (Order of magnitude = 12/26 mm), it represents thediameter of the vertical reinforcement;

Diameter of the wall bars:

Expressed in mm (Order of magnitude = 10/14 mm), it represents thediameter of the horizontal reinforcement;

Compressed reinforcement/stretched reinforcement ratio:

This is a dimensionless number (Usually imposed by the regulations on thebasis of considerations also made with regard to the duct ility of the section.In any case it will lower than or equal to 1);

Minimum net air gap:

Minimum net distance between the bars expressed in cm (must be

compatible with the size of the inert material used for the packaging of theconcrete. In any case it has an Order of magnitude = 2.5/5 cm);

Maximum air gap


Side concrete cover:

Measured starting from the barycentre of the bars, expressed in cm (Orderof magnitude = 4/6 cm);

Clamping diameter:

Expressed in mm (Order of magnitude = 8/10 mm), it represents the diameterof the transversal reinforcement;


Expressed in cm (Usually imposed by the regulations, in any case Order ofmagnitude = 15/25 cm)

Maximum distance between the arms of the clamps:

Expressed in cm (Order of magnitude 14/26 cm);

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CONNECTING BEAM:

These data are used for the planning and structural checks carried out on thehead connecting beam realized on bulkheads made up of piles:



Diameter of the wall bars:


Compressed reinforcement/stretched reinforcement ratio:

This is the dimensionless number (usually imposed by the regulations on thebasis of considerations also made with regard to the ductility of the section. Inany case it will lower than or equal to 1);

Minimum net air gap:

Expressed in cm (must be compatible with the size of the inert material usedfor the packaging of the concrete. In any case, Order of magnitude= 2.5/5 cm);

Maximum air gap


Side concrete cover:

Measured starting from the barycentre of the bars, expressed in cm (Orderof magnitude = 4/6 cm);

Clamping diameter:



Expressed in cm (Usually imposed by the regulations. In any case, Order ofmagnitude = 15/25 cm)

Maximum distance between the arms of the clamps:

Expressed in cm (Order of magnitude 14/26 cm);

4 Data Analysis

4.1 General data

The general data are equivalent to the ones seen in the section relevant to"New" menu. The environment for the management of the general data is thefollowing:

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Data Analysis 31


Figure: Environment for the management of the general data

We remind, just for the sake of completeness, the general data to be entered:

Project:

Identifies a synthetic description of the project to be executed. It includesthe possibility to print this data in course of exportation in rtf format. To dothis you must only tick off the square (with a red edge and a diagonal line)situated on the right side of the text box containing the description of theproject;

Date:

This is the date which will appear in the calculation report;

Regulations:

It is possible to select the regulations connected to the geotechnicalchecks (GEO Regulations) or the ones connected to the structural checks(STRU Regulations). For each category of check, the following choices arepossible:

GEO Regulations:

Eurocode 8

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STRU Regulations:

Eurocode

Calculation of pressures:In this group of data are defined the theories which can be used for thecalculation of the active thrust coefficient, for the passive thrust coefficientand for the limit state coefficient (active or passive) in dynamic conditions.In particular, the following options are possible:

Active pressures:

It is possible to use the Coulombs theory, Muller-Breslaus theory or Caquot-Krisels

theory;

Passive pressures:

It is possible to use the Coulombs theory, Muller-Breslaus theory or Caquot-Krisels

theory;

Seism ic pressures:

It is possible to use the Mononobe-Okabes theory.

Calculation model:It is possible to select a priori the calculation approach for the determinationof the stresses and displacements. In particular, it is possible to choose theLEM method (Limit Equilibrium Method) or the FEM method (Finite ElementsMethod).

NB: At this level of the programme, it is not possible to change the data

relevant to the geometry of the model, since they do not fall within the

ambit of the general data of the problem.

4.2 Ground geometry

The data relevant to the geometry of the ground are necessary for the definitionof the topographic state of the ground. The environment for the management ofthe ground profile is the following:

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Data Analysis 33


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Figure: Environment for the management of the ground profile, in terms of left coordinatesand of right angles and distances.

The data to be entered in order to correctly define the ground profile are the following:

Data entered by coordinates:

It is a question of entering the coordinates of vertices which define the profilewith regard to a fixed reference system. The vertices must be entered from uphillto downstream in terms of x-z coordinates. The coordinates must be expressed inm;

You must also enter the inclination of the uphill and downhill profile;

It is possible to view the numbers of the vertices.

Data entered by angles and distances:

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Data Analysis 35


Excavation height (H):

Expressed in m, it represents the part which will remain above ground after the

execution of the excavat ion;

Downhill stretch length (LV):

Expressed in m; it is necessary to carefully estimate this quantity especially for

the analysis of the global stability and for the analysis of the filtration

phenomenon (Order of magnitude = 1/2 times the excavation height);

Downhill ground inclination (IV):

Expressed in grades (depends mainly on the topographic conditions of the

problem);

Uphill stretch length (LM):

Expressed in m (the same considerations made for the length of the

downhill stretch are valid);

Uphill ground inclination (IM):

Expressed in grades (its value is based on the topographic configuration of the

case under examination);

Gradients for the calculation of the profile:

Expressed in grades, both uphill and downhill, they represent the values used by

the programme for the calculation of the thrust with inclined profile; their value is

based on the topographic configuration of the case under examination, but it

must be specified that the formulas used for the calculation of the active and

passive thrusts generally have validity limitations precisely on such parameter;

It is possible to view the numbers of the vertices;

NB: The insertion of the data in terms of angles and distances is only anintegrative not a substitute instrument of the insertion of the vertices interms of coordinates. In actual fact, also after the insertion of the angles anddistances it is necessary to click on the Generate coordinates button, which letyou go back to the window relevant to the vertices.

Seeing the importance that the insertion of the data in terms of coordinates of thevertices has, some specifications must be made.

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The reference system with regard to which the coordinates of the vertices

are defined as always its origin in correspondence of the head of the

bulkhead;

The succession of the vertices must be entered in the downhill-uphill

order.

You can refer to the following figure:

Figure: Reference diagram for the insertion of the vertices.

We report, for the sake of completeness, a guide figure for the insertion of the

geometrical data by angles and distances.

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Data Analysis 37


Figure: reference diagram for the insertion of the data by angles and distances.

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4.3 Structure

The data relevant to the structure concern the structural composition of thebulkhead. Through this set of data we then define the section (or the sect ions, ifneed be) of the bulkhead, materials, etc. the environment for the management of

the data relevant to the structure is the following:

Figure: Environment for the management of the data relevant to the structure

The structural composition is obtained by assembling elements possibly havingdifferent sec tions. So, for instance, it is possible to use different sec tions resistant

to excavation tracts for the same bulkhead. The following figure provides anexplanatory description of the previous concept:

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Data Analysis 39


Figure: Structure composition

The data to be entered for the structure refer to each stretch in which the

section can be susceptible of changes. For each stretch it is therefore necessary

to define the following:

Stretch length (Li in figure)

Expressed in m, it represents the constant-sect ion stretch of the excavationheight; it is a good practice to use sections with equal features for the wholebulkhead; in any case, where it becomes necessary to arrange more types ofsect ions, it is advisable to avoid too long tracts;

Type of section to be associated to the stretch considered

You can choose amongst the different types of sec tions defined in the Sections

Archive.

NB: The lengths are referred to each stretch and the structural continuity ofthe work (from the end of previous stretch) must be respected. For the firststretch, the length is defined wit regard to the zero of the reference system.

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In the following figure, derived from the software, is shown a diagram of abulkhead made up of more types of sections:

Figure: Bulkhead made up of more types of sections

4.4 Stratifications

For each analysis phase, different stratifications can be defined. Eachstratigraphy is characterized by the presence of more materials (i.e. more

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Data Analysis 41


grounds). The environment for the management of the stratifications is thefollowing:

Figure: Environment for the management of the stratifications

For each layer, the following data must be defined:

?

Identifies the layer by an ascending numeric index from the most superficial(above) to the deepest one (below);

Grounds DB

Allows setting initial characteristics derivable from a grounds databaseprovided with the programme;

WeightExpressed in kN/m3 (order of magnitude = 17/20 kN/m3), it represents the

natural weight per volume unit of the ground;

Saturated weight

Expressed in kN/m3 (order of magnitude = 18/21 kN/m3), it represents thesaturated weight per volume unit to be entered if the layer isconcerted by the presence of water; in case of soils situated upon agroundwater, for the analysis in drained conditions, the programme estimatesthe effective pressures starting from the lightened weight per volume unit;

Cohesion

Expressed in kN/m2 (order of magnitude 1/5 kN/m2);

Inner angle of friction

Expressed in degrees (order of magnitude = 22/30);

Over-Consolidation Ratio (OCR)

Depend on the tensional history of the site under examination (order ofmagnitude = 1/2)

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Edometric modulus

Is the normal modulus of elasticity estimated in edometric conditions,expressed in kN/m2 (Order of magnitude = 10000 kN/m2);

Uphill earth-wall angle of friction

Expressed in degrees (order of magnitude = 10/12. As a rule, the regulationsimpose values no higher by 2/3 than the inner angle of friction of theground);

Downhill earth-wall angle of friction

Expressed in degrees (the same considerations made at the previous pointare valid);

Layer thickness

Estimated starting from the lowest point of the layer previous to the one to

be defined; it is expressed in m;

Layer inclination

Expressed in degrees;

Colour:

Identifies the layer inside the drawing area;

Description

Name associated by the user to the inserted layer.

Some clarifications must be made as regards the definition of the layer thicknessand inclination:

Layer thickness

The thickness of the layer is measured along the vertical passing through theorigin of the fixed reference system (which, bear in mind, coincides wit thehead of the bulkhead). For more clearness, please refer to the following figure:

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Data Analysis 43


Figure: Definition of the thickness of the generic layer

Layer inclination

The inclination of the layer is the angle of rotation relevant to the bottom ofthe layer taken into consideration. The rotation of the layer is defined withregard to the pole obtained through the intersection between the vertical linepassing through the origin and the horizontal line which identifies the lowerpart of the layer to be defined.

4.5 Graundwater

The presence of a possible groundwater conditions the calculation both from thegeotechnical and structural point of view. That is why in the software the effectof the groundwater is taken into consideration including with reference topossible filtration problems.

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Figure: Environment for the management of the groundwater

As regards the groundwater, the data to be entered are the following:

Uphill groundwater depth

Is the depth with respect to the horizontal level passing throughthe reference general system of the free surface of thegroundwater uphill the bulkhead, expressed in m;

Downhill groundwater depth

Is the depth with respect to the horizontal level passing throughthe reference general system of the free surface of thegroundwater downhill the bulkhead, expressed in m;

Siphoning check

Allows carrying out or not the siphoning check (by now compulsory asprovided for by the regulations in force); said check is executedupon the first (i.e. the shortest) flowline.

Activates presence of groundwater in this phase

As it has already been mentioned above, the software allows definingmore calculation phases. Through this information it is possible tochoose whether the groundwater must be considered in the calculation ofthe current phase;

Impermeable layer thickness

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Data Analysis 45


Identifies the depth at which the impermeable layer is situated,expressed in m;

Flowlines pitch

Defines the density of display of the flowlines, expressed in m;

Mesh view

Allows viewing the calculation grid used for the solution of thefiltration problem;

Flowlines view

Allows the display of the flowlines;

It is possible to choose the colours of the calculation grid and of the flowline;

Generate flow grid

Allows carrying out the filtration analysis;

As regards the data which define the profile of the groundwater it isadvisable to refer to the following figure:

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Figure: Reference for the definition of the profile of the groundwater

In the figure, PFM is what in the groundwater data window is defined asthe uphill groundwater depth, while PFV is what in the groundwater datawindow is defined as the downhill groundwater depth.

4.6 Anchoring System

This subject has been partially treated in the Anchoring stringcoursessect ion. Inthis sect ion we are about to discuss the insertion of the fastening anchors.

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Data Analysis 47


Figure: Environment for the insertion of the fastening anchors

For a correct definition of the fastening anchors, it is advisable to enter thefollowing data:

Description

Allows the user to identify by means of a name the anchor inserted;

xIt is the abscissa, measured in the general reference system, into which

the fastening anchor is inserted. It is expressed in m;

z

It is the level, measured along the vertical passing through the generalreference system, into which the fastening anchor is inserted. It isexpressed in m;

Inclination

It is the angle of inclination that the axis of the anchor forms with thehorizontal axis of the general reference system. It is expressed in degrees(NB: the inclination is defined as positive when clockwise);

Interaxis

It is the distance, measured in the direction perpendicular to the drawingplane (general direction y) existing between two adjoining anchors. Itis expressed in m;

Angle of friction

It is the angle of friction between the anchor bulb and the ground wherethis latter is fastened (Order of magnitude = inner angle of friction ofthe ground). It is expressed in degrees;

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Adhesion

It is a measure of the cohesion which is measured on the interface betweenthe bulb and the soil (in the anchoring area). It is expressed in kN/m;

Typology

Refers to the type of fastening anchor. It must be chosen from the Anchorsarchive;

Stringcourse

It is the stringcourse by means of which the anchor is fastened to thebulkhead. It must be chosen from the fastening stringcoursesarchive;

Active/Passive

Is the option through which the user can decide whether the anchor isactive (pre-stressed anchor) or passive (unloaded anchor in the

initial phase of the structure life);Initial traction

In case the anchor is active, it defines the extent of the pre-tension. It isexpressed in kN;

Safety factor

Imposed safety factor with regard to the collapse of the fastening anchor;

Rowes reduction factor

It is a coefficient which depends on the deformability of the piling. Thiscoefficient reduces the maximum moment calculated on the bulkhead;

Free of fixed end

Detects if the insertion of the anchor involves a fixed bound for thebulkhead (Fixed end) or, on the contrary, it can be considered asnon-existent in terms of bounds;

Thrust coefficient:Please refer to the calculation of the anchors limit load.

4.7 SupportsThe supports are elements aimed at increasing the resistance resources of thebulkhead. However, unlike the fastening anchors, they are mostly subject tocompression. Consequently, the nature of the checks to be carried out changes.In the following figure is schematically shown the use of a strut support:

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Data Analysis 49


Figure: Strut support diagram

The strength checks carried out on the strut are the ordinary ones executed oncompressed members.

Compression strength test

In this test is estimated the maximum compression stress, comparingit with the breaking compression strain of the compressedelement;

Check concerning the collapse due to instability

As everybody knows, compresses members are subject to the problemof structural instability. It is therefore necessary to check that thenormal stress acting upon the strut is lower than or equal to the critical loadof the strut.

The support is an element which can only be inserted if you choose the FE Mmethod, and the element only reacts if a displacement of the bulkhead is

activated in a downhill direction.

4.8 Loads

In the Bulkheads software it is possible to take into consideration the presenceof possible loads distributed by Lines, Strips or Uniform Loads.

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Figure: Environment for the management of the distributed loads.

The data to be entered for a correct definition of a load are the following:

Description

Identifies the load; data necessary for the identification of the act ion in the loadcombinations;

Type

You can choose amongst load lines, load strips and uniformly distributed load;

xi

It is the abscissa starting from which the load starts acting. In case of load lines,it is the abscissa which defines the application of the load line; it isexpressed in m.

xf

Said data is required if load strips or uniform loads are defined. It is the final

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Data Analysis 51


abscissa of the load (so, it defines the extension of the load); it is expressedin m.

yi

Defines the abscissa (measured orthogonally to the drawing plane) starting from

which the load distribution starts acting; it is expressed in m.Yf

Defines the abscissa (measured orthogonally to the drawing plane) which identifiesthe end of the distributed load (so, it defines the extension of the loadorthogonally to the drawing plane); it is expressed in m.

Depth

Expressed in m. Currently, it only has a graphic value. Therefore, the increase instress induced by the overload is in any case estimated starting from the head ofthe bulkhead.

Q

Expressed in kN (in case of load line) or in kN/m (in case of strip and uniformload).

Colour

Assignation of the colour to be used for the display of the load strip.

For the interpretation of the different types of load, it may be useful to have a look atthe following figures:

Figure: Orthogonal load strips

For load strips, the distribution of the strains is estimated according to the z depth.

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A partially shared load with an initial abscissa x1 and a final abscissa x2 generates adiagram of pressures upon the wall whose values have been determined according tothe TERZAGHI formulation, which expresses the pressure at a generic z depth, asfollows:

)2(2)(

A

Qzq

A = sen( -sen(

B = cos( -cos(

arctg(z/x1)

arctg(z/x2)

By integration, the resultant and the relevant arm will be obtained.

Figure: Schematization of the load lines

In this case too, as for the load strips, the distribution of the strains is estimatedaccording to the z depth. The load lines generate a rise in the pressures uponthe wall, which, according to BOUSSINESQ at the z depth can be expressedas follows:

2222 )(

2),(

zxzx

Vzxx

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Data Analysis 53


2222 )(

2),(

zxzx

Vzxxz

Where the symbols have the following meaning:

V = Intensity of the load expressed in [F/L];

X = Distance, in horizontal project ion, of the point of application of the loadfrom the wall;

If the action plane is inclined by , the reference system (x,z) is rotated in (X,Z)

through the following transformation:

)sin()cos(

)sin()cos(

xzZ

zxX

4.9 Forces Applied

The software allows considering forces and moments like concentrated loadsacting upon the bulkhead.

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Figure: Environment for the management of the forces applied

For a correct definition of a concentrated force, it is necessary to define thefollowing data:

Description

This information identifies the force with a name; its insertion isnecessary for the purposes of its identification in the combinations of load;

Type

This information identifies the type and direction along which the forceacts. You can choose amongst the following types of load:

Nz, expressed in kN/m. It is a vertical force, whose direction is thuscoincident with the vertical reference axis;Fx, expressed in kN/m. It is a horizontal force whose direction iscoincident with the horizontal reference axis contained in the drawingplane;Fy, expressed in kN/m. It is a horizontal force whose direction iscoincident with the reference axis orthogonal to the drawing plane;

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Data Analysis 55


Mx, expressed in kNm/m. It is a moment whose axis vector is thehorizontal reference axis contained in the drawing plane;My, expressed in kNm/m. It is a moment whose axis vector is thereference axis orthogonal t the drawing plane;

yf

Expressed in m. It is the level at which the point di application of theforce (or moment) is positioned;

Value

It is the value corresponding to the intensity of the force. The signagrees with the global reference system; it is expressed in kN/m (for the

forces) or in kNm/m (for the moments);

ColourIt is the c olour used to view the drawing of the force;

IDIt is an identification index of the force;

In any case, it is useful to refer to the following figure:

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Figure: Convention for the definition of the concentrated forces

4.10 Pressures assigned

The distribution of the pressures act ing upon the bulkhead (including when youhave to calculate the nodal forces using the FEM method) is determined on thebasis of the application of the classical methods (e.g. calculation of thehorizontal pressure using Rankines method). However, it is possible to beconfronted by situations in which the distribution of the horizontal pressures,

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Data Analysis 57


though it is known, does not follow the expected progress. The software allowsmanaging these situations through the manipulation of the calculated distributionof pressures, integrating or replacing it with a distribution inserted by the user.the environment for the menagement of the pressures assigned is the following:

Figure: Environment for the management of the pressures assigned

I dati da inserire per una corretta definizione delle pressioni assegnate sono iseguenti:

Z:

Expressed in m. It is the share to which it requires that the pressure is put

on the determined value;

Value:

Expressed in kPa. It is the value of the pressure corresponding to the share

z;

Add to diagram:

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This check is necessary if the pressure assigned must to replace or to

superimpose to calculated diagram;

Colour:

Identifies the colour of view of the diagram until the share z;

4.11 Modulus of subgrade reaction assigned

In the framework of analyses carried out using the method of finished elements, it ispossible to manage the stiffness of the springs which schematize the ground.

Figure: Environment for the management of the modulus of reaction

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Data Analysis 59


The data relevant to the imposition of the value for the modulus of subgrade reactionare the following:

Node

It is the node (in the framework of the discretization to finished elements) upon

which you want to impose the assigned stiffness;

Depth

It is the depth at which the node is positioned, or possibly the depth at which you

want to fix the modulus of subgrade reaction;

Method Calculation

It is the calculation method through which the modulus of subgrade reaction must

be determined. The software allows choosing amongst the following options:

User

The user can select different soils, from the pull-down text box, each being

associated to a range of values for the modulus of subgrade reaction. The user an

directly enter the numerical value for the modulus of subgrade reaction click the double

blue arrow in order to assign the entered value;

Bearing capacity

According to the method which exploits the concepts of bearing capac ity, the

modulus of subgrade reaction is calculated on the basis of the following formula:

n

sss zBAk

The user must enter the parameters As, Bs and n so as to allow the software tocalculate the modulus of subgrade reaction applying the formula;

"The most general form of either a horizontal ora lateral modulus of subgrade reaction is

Ks = As + BsZn (9-10)

where: As= constant for either horizontal or

vertical numbers

Bs= coefficient of depth variationZ= depth of interest below ground

n= exponent to give ks the best fit(if load test or other data are available)

Either Asor Bsin this equation may be zero; at

ground surface Asis zero for a lateral ksbut at

any small depth As> 0. For footings and mats

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(plates in general), As> 0 and Bs 0.Equation

(9-10) can be used with the properinterpretat ion to the bearing-capacityequations of Table 4-1 (with difac tor dropped)

to give

qult = cNcsc + ZNqsq +0.5 BN

s (9-10a)

Observing that

As= C(cNcSc+ 0.5 BN s )

and BsZ1= C( Nqsq)Z

1

We obtain a ready means to estimate ks. Inthese equations the Terzaghi or Hansenbearing-capacity factors can be used. The Cfactor is 40 for SI units and 12 for Fps, usingthe same reasoning that qult occurs at a

0.0254-m and 1-in. settlement but with no SF,since this equation directly gives qult.Where

there is concern that ksdoes not increase

without boundwith depth Z, we may adjust theBsZ term by one of two simple methods:

Method 1: Bstan-1 (Z/D)

Method 2: (Bs/Dn)Zn = BsZ

n

where D= maximum depth of interest, say,the length of a pile

Z = current depth of interest

N = your best estimate of theexponent

Table 9-1 may be used to estimate a value of k

sto determine the correct order of magnitude

of the subgrade modulus obtained using one ofthe approximations given here. Obviously if acomputed value is two or three time larger thatthe table ranger indicates, the computationsshould be rechecked for a possible gross error.Note, however, if you use a reduced value ofdisplacement (say, 6 mm or 12 mm) instead of

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Data Analysis 61


0.0254 m you may well exceed the table range.Other than this, if no computational error (or apoor assumption) is found then use judgment inwhat value to use. The table values areintended as guides. The reader should not use,

say, an average of the range given as a goodestimate. "

Joseph E. Bowles (1997), "Foundation analysis and design"

Joseph

E.

Bowles

(1997),

"Foundati

on

analysis

and

design"

Joseph E.

Bowles (1997),

"Foundation

analysis and

design"

Chiarurgi-Maia Method

This method is used to calculate the modulus of subgrade reaction on the

basis of the modulus of subgrade reaction, of the diameter of the piling

and of Poissons ratio. The formula applied to calculate the modulus of

subgrade reaction using this method is the following:

12

14

2 )1( EJ

dE

d

Ek ededs

In the previous formula, Eed is the soil edometric modulus, d is the diameter of the

pile, nis Poissons ratio ad EJ is the flexural stiffness of the piling.

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Jamiolkowskis Method

This method is used to calculate the modulus of subgrade reaction on the basis of

the following parameters:

Secant modulus of elasticity, expressed in kPa;

Dimensionless coefficient which depends on the model of bound assumed for the

calculation of the bulkhead (it is equal to 1 for free bulkheads);

Dimensionless coefficient which depends on the depth at which to calculate the

modulus of subgrade react ion;

Bulkhead embedment depth, expressed in m;

In particular, Jamiolkowskis method refers to the secant modulus of elasticity of

the ground corresponding to the activation of 50% of the limit pressure. Therefore,

for the calculation of the modulus of subgrade reaction, the following formula is

applied:

p

s

s Ct

Ek

50,

In the previous formula, t is equal to the embedment depth and r is a dimensionless

coefficient equal to 1 for the free diaphragm on the foot or to the ratio of the

position of the null displacement point beneath the dredge line to the embedment

depth for the diaphragm with partial fixed joint on the foot. Cp is a dimensionless

depth coefficient estimated using the following formula:

)1(2

1

t

zCp

Schmitts Method

This method is used to calculate the modulus of subgrade reaction on the basis of

the diameter of the section, of the modulus of elasticity of the ground and of the

modulus of elasticity of the material constituting the structure. In particular,

Schmitt proposes to refer to the edometric modulus of the ground Eed as well as

to the stiffness relevant to the supporting structure (expressed through the

characteristic length of the beams on a Winkler foundation), obtaining:

3

1

3

4

1.2

EJ

Ek

ed

where Eed is the edometric modulus of the ground, while EJ represents the flexural

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Data Analysis 63


stiffness of the bulkhead.

Mnards Method

This method is used to calculate the modulus of subgrade reaction of the ground

on the basis of the results of tests carried out using the Mnard pressure-meter.

In particular, the modulus of subgrade reaction is estimated on the basis of the

following factors:

o Em, expressed in kN/m2

o Coefficient which takes into account the viscous behaviour (dimensionless

coefficient);

o Characteristic length, expressed in m;

In particular, this method refers to the pressuremetric modulus of the ground EM,

obtained experimentally through a pressuremetric test:

)9(13.02

LL

Ek M

Where alpha is a coefficient which takes into account the viscous behaviour of the

ground, and L is a characteristic length that the author indicates as corresponding

to 2/3 of the bulkhead embedment depth.

4.12 Boundary Conditions

In some situations there can be conditions on the displacements, rotations or springs which must be respected beforehand in the calculation procedure. In this case, we referto an an imposition of the boundary conditions. The software allows managing theboundary c onditions.

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Figure: Environment for the management of the boundary conditions

In order to correctly impose a boundary condition, it is necessary to enter the

following data:

Description

Identifies the boundary condition to be imposed by means of a name;

Z

Expressed in m. It is the depth at which to impose the boundary

condition;

Type

It is the type of condition it is possible to manage. In SPW, the following

boundary conditions can be managed:

Free

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Data Analysis 65


Through this condition, you can impose the node at z level to be free

and consequently by no means bound;

Displacement, expressed in m.

It is possible to impose for a certain depth (z) the displacement to

be equal to the imposed one;

Rotation, expressed in degrees.

It is possible to impose for a certain depth (z) the rotation of the

elastic line of the bulkhead to be equal to the imposed one;

Spring.

It is possible to insert a spring at the z depth which simulates an

elastically yielding bound.

Value

It is the value of the imposed boundary condition. The unit of

measurement to be taken into consideration is the one associated to the

type of imposed condition (m for displacement, degrees for rotations, kN/

m for the spring);

Colour

Colour to be used for the display of the possible imposed condition;

ID

It is the index which identifies univocally the imposed boundary condition.

5 Analysis

5.1 Analysis

The analysis of the bulkhead is organized by analysis phases and load combinations. Inparticular, it is possible to define more analysis phases, which differ from one another onthe basis of the input data. For each analysis phase, it is possible to define more loadcombinations. The environment that manages the analysis of the bulkhead and related

phases and load combinations is the following:

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Figure: Environment for the management of the analysis of the bulkhead

The main considerations to be made as regards the analysis procedure are the following:

It is possible to analyzer more constructive phases, and for each of

them to analyze more load combinations;

To each load combination, it is possible to associate the type of checks

to be carried out and consequently whether to carry out checks in the

ultimate limit states (SLU) or in the limit operation states (SLE);

It is possible to enter the seismic coefficients manually.

It is possible to manage the partial amplification factors for the loads as

well as the partial reduction factors for the materials.

In order to carry out the analysis of the bulkhead (all phases and

combinations) it is necessary to click on the calculate button.

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Analysis 67


5.1.1 Interference between the phases

Allows having interference between the phases.Each phase is initialized on the basis of interaction with the previous phase.

Even in absence of anchors, it is possible to detec t a difference in stress between thephases, due to the interaction of stress field of the current phase from the previous.Diagrams of pressure will be related to the stress field of phase.Activating this command, will be created automatically load conditions in the currentphase relative to the previous.If there is a difference of displacement between the phases, will act ivate the passiveanchors.In the analysis in phases is not possible to calculate automatically the depht of piling.

N.B.: if the comm and is not active there is no interference be tween the phas es

5.2 Pressures diagrams

It is possible to view the diagrams of the pressures generated in the calculation. In orderto view the diagrams, it is necessary to click on "Pressures diagram" from the Calculationmenu.

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Figure: Drawing of the pressures diagram

It is also possible to view the values of the diagrams directly on the drawing area.

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Analysis 69


5.3 Solicitations diagrams

It is possible to view the diagrams resulting from the analysis of the solicitations.In particular, it is possible to view the diagrams of the pressures, moment, shear anddisplacement.You can choose to view the diagrams for any analysis phase as well as for each loadcombination.

5.4 Results of the structural analysis

It is possible to get immediate information on the results of the structural calculation of

the bulkhead sections. In order to open the environment for the management of theresults of the structural calculation it is necessary to click on "Results of the structuralanalysis" from the "Calculation" menu.

Figure: View structural analysis

The environment for the management of the results of the structural analysis isfollowing:

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Figure: Results structural analysis

The results it is possible to consult are the ordinary ones of a structural analysis(Ultimate state stresses, maximum deformations, maximum strains, neutral axis position,results of the tests, etc .).

5.5 Fastening area of the anchors

The fastening anchor, seen as an element aimed at integrating the strengthresources of the bulkhead, is only useful if the anchoring occurs in stable areas

of the ground. It is thus necessary to estimate with certainty the most suitablearea in which to fasten the anchor. The principle according to which tocalculate the anchoring area is to identify that ground surface where theactive zone does not intersect with the passive zone (Bowles Foundationsproject and analysis, page 693). The procedure used in the software is thefollowing:

Identify along the bulkhead, near (or beneath) the dredge line the position of the

point where the bending moment is nullified;

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Analysis 71


Start from the point of null moment, tracing out two lines inclined by 45-f/2 and 45

+f/2, respect ively (Rankine zones);

At this point, position the anchoring so that its end is in the zone traced with a

broken line and beneath the AD line in the following figure, in order to obtain the

utmost performance. If the anchoring end (fixed point) is positioned in the BCD zone,

the anchoring wedge is limited to the BC line, but you cannot obtain the maximum

performance of the anchor.

Figure: Determination of fastening area of the anchors

6 Export report

6.1 RTF Export

The software allows exporting results in rtf format (i.e. the generation of thecalculation report).For export in rtf format you just need to click on the "Export rtf" button from the"Export" menu. A window will open, allowing you to select the parts of the report tobe printed:

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Figure: Environment for the export of the report in RTF format

As you can easily see, the select ion of the parts to be printed can be madeboth with reference to the constructive phases, to the combinations, to thedata and to the results. As a result, a streamlined document, smooth-flowingbut at the same time significant with regard to the subject of the report, will beprinted.

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Export report 73


Figure: Editor of text

6.2 Export DXF

The software allows exporting results in dxf format (i.e. the generation of a graphicprintout).For exporting in dxf format, you just need to click on the "Export dxf" button fromthe "Export" menuA window will open, allowing you to select the path where to save the dxf file.

In the export file you can manipulate the reinforcement and the geometricalmodel of the calculation.

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