GP E Prestressing Basic AASHTO Imp

RM Bridge Professional Engineering Software for Bridges of all Types

RM Bridge V8i

March 2012

TRAINING PRESTRESSING BASIC

MODELER AASHTO [IMPERIAL UNITS]

RM Bridge

Training Prestressing Basic MODELER AASHTO [IMPERIAL UNITS] I

Bentley Systems Austria

Contents

1 The Basic Example ..................................................................................................... 1-1

1.1 Structural System ................................................................................................. 1-1

2 Pre-arrangements and basics ....................................................................................... 2-1

2.1 Program start ........................................................................................................ 2-1

2.2 Creating a New Project ........................................................................................ 2-1

2.3 Description of the Main Program (Analyzer) Interface ....................................... 2-5

2.4 Description of the Modeler Interface ................................................................... 2-6

3 Lesson 1: Starting with Modeler ................................................................................. 3-8

3.1 General ................................................................................................................. 3-8

3.2 Construction of the Axis ...................................................................................... 3-9

3.2.1 Creating an Axis ........................................................................................... 3-9

3.2.2 Construction of the Axis in Plan View ....................................................... 3-10

3.2.3 Construction of the Axis in Elevation (Vertical Projection) ....................... 3-13

4 Lesson 2: Definition of Cross-Sections ...................................................................... 4-1

4.1 Creation of an Cross-section ................................................................................ 4-1

4.2 Definitions ........................................................................................................... 4-4

4.2.1 Construction Lines (CL) ............................................................................... 4-4

4.2.2 Cross-section and Axis ................................................................................. 4-4

4.2.3 Cross-section ................................................................................................. 4-4

4.2.4 Cross-Section Elements ................................................................................ 4-4

4.2.5 Parts .............................................................................................................. 4-5

4.2.6 Reference-Sets .............................................................................................. 4-5

4.2.7 Layer ............................................................................................................. 4-5

4.3 Definition of the Construction Lines ................................................................... 4-5

4.4 Cross-Section Elements ..................................................................................... 4-13

4.5 Editing in the Cross-Section window ................................................................ 4-15

4.5.1 Object selection ........................................................................................... 4-15

4.5.2 Construction line editing ............................................................................. 4-16

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Training Prestressing Basic MODELER AASHTO [IMPERIAL UNITS] I I


4.5.3 Editing of FE-Elements .............................................................................. 4-18

4.6 Definition of Reference-Sets ............................................................................. 4-19

4.6.1 Attribute sets ............................................................................................... 4-20

4.6.2 Reference-Sets Basic input description ................................................... 4-20

4.6.3 Creating a Reference-Set for Stress check points ....................................... 4-21

4.6.4 Reference-Sets for non-linear temperature gradient ................................... 4-24

4.6.5 Reference-Sets for longitudinal reinforcement ........................................... 4-27

4.6.6 Reference-Sets for shear reinforcement ...................................................... 4-31

4.6.7 Reference-Sets for torsion reinforcement ................................................... 4-36

4.7 Definition of the Pier Cross-Section .................................................................. 4-38

4.8 Dimensions ........................................................................................................ 4-40

5 Lesson 3: Definition of Segments ............................................................................... 5-1

5.1 Definition of Main Girder Segments ................................................................... 5-1

5.1.1 Definition of the Segment ............................................................................. 5-1

5.1.2 Definition of the Segment points .................................................................. 5-2

5.1.3 Numbering and material assignment ............................................................ 5-6

5.2 Definition of Tables and Formulas ...................................................................... 5-9

5.3 Assigning Tables to Variables ........................................................................... 5-15

5.4 Definition of the Pier Segments ......................................................................... 5-18

5.4.1 Definition of the Connection points in the Main girder cross-section ........ 5-18

5.4.2 Definition of pier segments ......................................................................... 5-19

5.4.3 Definition of segment point for the Pier segment ....................................... 5-20

5.4.4 Numbering and material assignment .......................................................... 5-21

6 Definition of bearings and connections .................................................................... 6-23

6.1 Rigid connection between pier and main girder segment .................................. 6-24

6.2 Connection between ground and pier ................................................................ 6-26

6.3 Copying the pier segment .................................................................................. 6-28

6.4 Definition of abutments ..................................................................................... 6-29

7 Export to Analyzer ...................................................................................................... 7-1

8 Data management ....................................................................................................... 8-3

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Training Prestressing Basic MODELER AASHTO [IMPERIAL UNITS] 1 - 1


1 The Basic Example

In the following example a three span concrete hollow box girder shown in the picture

below will be defined. The bridge is built in three construction stages.

Figure 1-1: General view of the example.

The 455ft long three-span bridge (130ft + 195ft + 130ft) is located on a compound axis

comprising a straight line, a spiral, and a circular curve. The cross-section of the main

girder is hollow box and varies along the station. The super structure consists of two

66ft tall piers and two abutments.

1.1 Structural System

40m 60m 40m

10x4m 10x4m 15x4m

A4 A1 A2 A3

20m

Figure 1-2: Structural system.

130 ft 195 ft 130 ft

10x13 ft 15x13 ft 10x13 ft

66 ft

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System axis: Horizontal plan

1st Part: Straight Line: Station: 0-65 ft

2nd

Part: Spiral: L=165ft, REND=650ft: Station: 65-230 ft

3rd

Part: Circle: R=650ft: Station: 230-455 ft

System axis: Vertical plan

1st Part: Line: dXabsolute=215ft, dZabsolute=3.5ft Station: 0-215 ft

2nd

Part: Line: dXdifference=240ft, dZabsolute=-1.0ft Station: 215-455 ft

Rounding with parabola by rounding a tangent point R=6500ft

Numbering system:

Node numbers (span): 101-111-126-136

Element numbers (span): 101-110,111-125,126-135

Axis 1 Axis 2

X

Z

101-110

Axis 3 Axis 4

111-125 126-135

Rigid pier connection

Figure 1-3: Supports (defined by additional elements).

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Figure 1-4: Cross-section of the main girder.

Table 1-1: Variable definition.

d_web_tab(sg)

d_bot_tab(sg)

h_cs_tab(sg)

Station Value Type

Station Value Type

Station Value Type

0 2-0 LINEAR 0 1-0 LINEAR 0 11-6 LINEAR

24 2-0 LINEAR 24 1-0 LINEAR 24 11-6 PARAB. TYP1






140 2-0 LINEAR

140 1-0 LINEAR

140 11-6 LINEAR

Figure 1-5: Pier cross-section.

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2 Pre-arrangements and basics

2.1 Program start

The program installation must be completed before any work can be started. The instal-

lation procedure automatically creates the following icon on the desktop:

The program can be started by double-clicking on the RM icon or by the selecting it in

the Windows-Start-Menu.

2.2 Creating a New Project

When starting the program for the first time, it loads the RM default

databases (materials, standard depended tables and variables) and cross-section

catalogue, and then changes to the installation directory (Figure 2-1). At each subse-

quent program start the program changes automatically to the most recently used work-

ing directory. The full path of the working directory is displayed in the title bar of the

program.

Figure 2-1: Start screen of RM Bridge.

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Changing the working directory (or creating a new one) can be done under menu

File Change Work Directory (see Figure 2-2).

Figure 2-2: Changing working directory.

Create a new directory by selecting the desired directory path and clicking on the

Make New Folder button. Create a directory called Training1 for this example. The directory structure chosen

for the work in this manual is C:\Training1.

Click the OK button to accept the displayed directory as the active project directo-

ry.

Figure 2-3: Start screen in new work directory (see path in the window title bar).

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In the selected directory a new Project will be created. This is done under menu

File Initialize Current Project.

This creates the RM Bridge database for the current project. All user inputs and outputs

(results) are saved in this database (note that after this step, the various menu items for

the user input become active).

Figure 2-4: Initialize Current Project.

In next few steps, by pressing on the Next button, the user can:

Define some basic project information

Select the design code

Select the material group

Select and modify units This tutorial will use English units. To select the proper units, first click the radio button for Imperial

Units, then click the button for custom units. Change the units for Length (Section) to inches. Leave all others the same.

Change Modeler and BrIM options

The input is confirmed by pressing on the OK button.

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Figure 2-5: Initializing Current Project.

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2.3 Description of the Main Program (Analyzer) Interface

Figure 2-6: Main program interface.

At the beginning of a project the view window for the static model is empty.

Note: By pressing the F1 button (or Menu HelpApplication Help) or clicking the help-symbol in the symbol list (the opened book) a help window, according to the window you are currently in,

will pop up.

To zoom there are so-called free-hand symbols. A detailed description of these symbols is obtained by selecting the mouse icon in the toolbar for general functions (or Menu

HelpFreehand Symbols).

Zoom-Functions

Navigation with menu-tree or

with menu bar

General menus: Calculation Messages, Windows Explorer, Errors and Warnings, Windows Calculator, Configured Editor, TDV Plot file browser, Free hand symbols, TDV Setup, Print /plot a file, Program help, TDF file viewer

Recalculation Import/Export of TCL files

Modeler Geometric Preprocessor

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2.4 Description of the Modeler Interface

By double clicking on the Modeler symbol in the navigation tree the Modeler (Geo-

metric preprocessor, formerly GP) is started. The same can be done under

Menu ModelerOpen Modeler (see figure below).

Figure 2-7: Modeler start.

When the Modeler is open, the main window will switch to the Modeler input window

(for now still an empty project in plan view is shown).

The picture below shows the Modeler main input window with an explanation of the

fundamental functions.

Recalc (Export of Modeler

data to Analyzer-RM)

Import/Export

Modeler TCL

Closing the

Modeler Functions for the Axis

definition in plan view

Modeler Navigation three

Input window for Axis in plan view

View and zoom functions

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Figure 2-8: Modeler main input window.

Depending on the selected menu item in the navigation tree (axis, cross-section, seg-

ments ), the input window and the input functions change.

The modeler is closed by selecting the button on the top right side (see Figure 2-8) or by

pressing Esc on the keyboard (or even by direct selecting one of the Analyzer input functions in the Navigation tree).

Note: The Recalc button (see Figure 2-8) in Modeler (GP) and Analyzer (RM) has different func-tionality. By clicking on it in Modeler, a window, for recalculating the project (data) in the Mod-

eler and exporting the Modeler data to the Analyzer, opens. On the other hand, by clicking on

the same button in Analyzer, a window for the recalculation in the Analyzer opens.

The same applies to the two buttons on the left side for Import/Export of the data. When the

Modeler is open, the import/export refers to Modeler data and when the Analyzer is open, the

import/export refers to Analyzer data.

An explicit description for data management and project back-up can be found in chapter 8.

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3 Lesson 1: Starting with Modeler

Note: GP= Geometrical Preprocessor, since RM Bridge V8i Modeler

3.1 General

The items that are required for defining a structural system are described step by step in

this introductory example. The following geometric data have to be defined:

axis The three-dimensional bridge axis is defined in the hor-izontal and vertical projections. Traditional roadway

geometry elements are used straight lines, spirals or clothoid, arches (circles) and cubic curves.

cross-section Preparation of different cross-sections used for super-structure and substructure (Here a typical hollow box

section for the main girder and a simple rectangle sec-

tion for the piers will be defined).

segment Different logical units of a bridge could be assigned to the same segment (e.g. Segment for main girder, seg-

ments for piers, segments for cross beam, etc.). These

segments are then connected together according to their

geometric position and static connections. The segmen-

tation of each segment has to follow the construction

sequence and cross-section variation.

structural model The complete structural model will be defined ready for load application and analysis using Analyzer.

The definition of an axis starts with the plan view in the global coordinate system (X-Z

plane). The first element of the axis in plan view is a start point, to which the required

starting station is assigned (X- and Z-coordinate). The definition of the axis elevations

view starts similarly with assignment of the starting station and height (Y-coordinate).

A segment is always created by assignment of a cross-section over a certain axis length.

The definition of the segment begining and end is defined by the station of the axis.

However, each segment is divided into more segment points segmentation. The seg-mentation of each segment has to follow the construction sequence and variation of the

cross section dimensions. In the segment point list in the Modeler each segment point

corresponds to a station on the axis and has a certain distance to the next segment point.

After exporting to the Analyzer the segment points becomes structural nodes and the

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length of the segments correspond to the length of the beam elements which are placed

between the nodes for the structural analysis.

3.2 Construction of the Axis

The geometry of an axis is defined by a series of axis elements. These elements in plan

view are straight lines, clothoid and arcs. The axis in elevation is constructed from

straight lines, parabolas, clothoid and arcs.

3.2.1 Creating an Axis Activate the axis definition by double clicking on Axes in the Modeler navigation

tree. A pop up window opens.

Figure 3-1: Insert a new axis.

The Axis name (Axis1) will be defined. Other definitions such as starting station and

increasing station numbering can be defined as per default.

The input is confirmed with OK .

The active axis is automatically displayed in the axis management window. Subsequent

axis definitions will be applied to Axis1.

Figure 3-2: List of existing axes.

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Training Prestressing Basic MODELER AASHTO [IMPERIAL UNITS] 3 - 1 0


Note: To define a simple axis (straight in plan and elevation view) the check button straight should be activated and then the axis length should be defined. At that point no further definitions are

needed the axis definition is finished.

More axes can be defined using the same principle. To add a new axis (after defining

the first one) right click on Axes under Modeler in the navigation tree and choose New Axis. To select a certain Axis double click on it. The active axis is shown in the comment line above the main input window. All definitions are always made for the

active axis (in this case Axis1).

Each axis has three sub-menus; two menus listing definitions in plan and elevation and

a menu for graphical presentation (and definition) of the selected axis in elevation.

(Note: For graphical presentation and definition of (all) axes in plan there is only one

shared window, which is the default window that appears when no other Modeler win-

dow is active).

3.2.2 Construction of the Axis in Plan View

System axis: Horizontal plan

1.Part: Line : Station: 0-65 ft

2.Part: Spiral: L=165ft, REND=650ft Station: 65-230 ft

3.Part: Circle: R=6500ft Station: 230-455 ft

Figure 3-3: Overview of the drawing functions for the definition of the axis in plan.

3.2.2.1 Definition of a Starting Point and a Starting Direction After Selecting the symbol P0 (see Figure 3-3) from the symbol list for the defini-

tion of the axis in plan view a window for the definition of the starting point opens.

Enter the coordinates of the starting point and the initial direction of the axis.

Definition of the starting point

Append straight line to axis

Append circle to axis

Append spiral/clothoid to axis

Append cubic curve to axis

Delete last axis element

Change between graphical presentation and list

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Figure 3-4: Starting point of the axis geometry in plan.

The default values are acceptable for the current example. Starting point P0 has the coordinates (X=0.0 and Z=0.0) in the global coordinate system. The axis starts parallel

to the x-axis with increasing station values towards the right side.

Accept the values by clicking OK .

The point and the direction are immediately displayed on the screen. Use the zoom

functions to see the axis in detail.

3.2.2.2 Definition of a Straight Line Select the Append straight line to axis symbol from the symbol group for horizontal

axis construction.

Enter the length of the straight line in the displayed input window.

Input 20 for this example.

Figure 3-5: Definition of a straight line in plan.

Confirm with OK .

Note: The input units in this example are meters. Input units and other general parameters are prede-

fined but can be changed by selecting the configuration button under Options and Units.

3.2.2.3 Definition of a Clothoid (Spiral) A spiral is defined by a parameter or length and the radius or curvature at each end.

The spiral in this example combines a straight line with a circle having a radius of

650 ft.

Select the Append spiral to axis symbol from the symbol group. Enter the desired spiral geometry in the opened input window.

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or

Figure 3-6: Clothoid definition in plan.

Input 165 for the Length or 99.8191 for the Parameter. Input 0 for the radius at the start. Input 650 for the radius at the end.

Confirm with OK .

3.2.2.4 Definition of an Arc Select the Append circle to axis symbol - the third symbol from top in the symbol

group for horizontal axis construction.

Figure 3-7: Insert a circle in plan.

Enter the desired arc geometry in the displayed input window:

Enter 225 feet for the length of the arc. Enter 650 feet for the radius of the circular curve in the displayed input window.

Confirm with OK .

Note: According to the general Modeler options (defined at initialization of the project) a positive radius creates a curve to left and a negative radius creates a curve to right (looking in the axis

direction). These settings can be changed under ModelerOptionsCurves.

Construction of the axis in plan view is now completed, and the axis is graphically dis-

played on the screen. The connection points between the different elements of the axis

are marked, and their station values are given.

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Figure 3-8: General plan view of Axis1.

A listing of the input for the plan definition of the axis can be viewed. You can find this

data under Ground plan list in the navigation tree. This window is an information window and parameters can also be modified here. To modify the input click on the

modify button or double click on a certain line in the list. The last listed element is always a point and is generated by the program automatically. To delete any component

click on the delete button .

3.2.3 Construction of the Axis in Elevation (Vertical Projection)

The axis in this example rises first with a positive gradient, peaks over a hill top and

falls on the other side. The slope of the final straight section is defined by the end slope

of the vertical curve at the hill top.

Axes can be shown as a list or as a graph

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System axis in elevation view:

1. Part: Line: dXabsolute=215ft, dZabsolute=3.5ft Station: 0-215 ft

2. Part: Line: dXdifference=240ft, dZabsolute=-1.0ft Station: 215-455 ft

3. Part: Parabola by rounding a middle tangent point R = 6500 ft

The axis (Axis1) remains active.

Open the input window for defining the vertical projection by clicking on the Eleva-tion list or Elevation graphic.

No vertical projection has been made yet and the displayed screen is blank. The tools

for the definition of the axis elements in the vertical projection are displayed at the right

side of this new input window.

Figure 3-9: Overview of the drawing functions for the definition of the axis in vertical plan.

Once again define a starting point (P0) and a starting direction.

Select P0, from the symbol group for vertical axis construction. Enter the station at point P0; define the level of the axis at this station and the direc-

tion of the axis in the displayed input window.

Leave the station height value as default 0.0.

Figure 3-10: Starting point in elevation geometry.

Definition of the starting point

Append a straight line (by station difference)

Append a straight line (by station difference and height)

Append a circle/arch (by station difference and radius)

Append a circle/arch (by station difference and height) Append a parabola (by station difference and height)

Change between graphical presentation and list

Delete last axis element

Rounding a tangent point by parabola with certain radius

Rounding a polygon of three lines by parabola

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Input 0 for the slope of the axis on the left side of the peak.

Confirm with .

As mentioned in 3.1, the starting point of the axis in vertical plan is defined by the sta-

tion and a corresponding height (Y-coordinate in the global coordinate system).

Note: The starting point of the Axis in vertical plan is identical to the starting point of the Axis in

ground plan, which is not necessarily always the case. It could be that the starting point of the

first tangent had to be outside of the defined Axis in ground plan. The same applies for the last

point of the axis in vertical plan. However, the interval used for the definition of the segment has

to be defined in both ground and vertical plan.

There are many different ways to define one and same axis. The slope of the first line (tangent) in

this example could be defined at the definition of the starting point and not, as it is done in this

example, by the definition of the height difference.

In RM Bridge V8i it is also possible to import an axis via a LandXML file. This can be done

under FileImport LandXML File.

The next step is the definition of both lines/tangents. Select the Append straight line by station and height symbol for each of the tangents. See input for each below.

Figure 3-11: First straight line by station and height difference.

Figure 3-12: Second straight line by station and height difference.

Note: The input of the station difference and height is always relative to a selected point. If absolute is

selected the input is relative to the starting point, if difference is selected the input is relative to

the last axis point.

Double click Elevation graphic in the menu tree. You will see the two tangents you have created and two new buttons for defining parabolas. Select Parabola by Round-ing A Tangent Point.

Note: The information of what has to be done is displayed also in the info line below the view window.

This is done for all commands (after selection) in Modeler. In this case, the message Click the point that has to be rounded is displayed.

Select the intersection of the constructed lines.

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A window for the definition of the radius opens. Enter 6500 feet for the radius of the vertical curve. A positive sign defines a hilltop (a negative sign would define a

valley).

Figure 3-13: Second straight line by station and height difference.

Confirm with OK .

The definition of the axis (in vertical plan) is finished now, and the three-dimensional

Axis 1 is completely defined.

Figure 3-14: Axis definition in vertical plan (elevation).

This window is an information window - parameters cannot be changed here. A listing

of the input for the elevation definition of the axis can be viewed by selecting Elevation list in the modeler menu tree. All parameters in the list can be modified using the same principle as the parameters in the Ground plan list. Clicking on 3D View in the tree menu allows you to view the axis in space.

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Figure 3-15: 3D view of the Axis in 3D.

In order to change the axis display, open the axis list by clicking on Axis and selecting the axis to be changed (Axis1).

Right click on Axis1 and choose Edit Axes.

Choose Extended in the next dialogue window.

Figure 3-16: Axis modification.

The following parameters can be changed through this window:

Color of points. Color of axis. Font size. Elevation scale.

Select OK to confirm the changes.

The screen display will be updated immediately after OK is selected in all open input

windows.

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4 Lesson 2: Definition of Cross-Sections

Figure 4-1: Cross-section to be defined.

4.1 Creation of an Cross-section

A new cross-section is created by double clicking on Cross Sections in the modeler menu tree or by right clicking and selecting New cross-section.

A pop up window opens for the new cross section.

Figure 4-2: Creation of a new cross-section.

Here the name of the cross-section and global FE mesh refinement is defined. For this example accept the default name Cross1 and value 1 for the refinement.

Click OK to create the new cross-section.

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The new cross-section will be immediately listed and automatically active in the cross-

section list.

Figure 4-3: List of existing cross-sections.

Note: A predefined cross-section from the RM cross-section catalogue can be imported also (see Fig-

ure 4-2). The parameters of the imported cross-section are variable and can be adjusted.

The Figure 4-4 shows the main input window for the cross-section construction with

explanation of the most important drawing functions.

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Funktin for drawing a Dimension (click

right for other dimensioning types).

Function for creation of a Reference point

(click right for other reference point types).

Function for drawing a stiffener.

Function for drawing a link element

(e.g. truss).

Delete unused construction lines.

Function for drawing Construction line

(click right for other element functions).

Function for drawing 4-point FE element

(click right for other element functions).

Axis reference point.

Basic construction lines CL1 and CL2

(Predefined directions of the Y and Z

coordinate axes of the Cross-section).

Reference-Set management

(open with click on the drop

down menu) and display of

the active Reference-Set.

Cross-section Part

management (open

with click on the drop

down menu) and

display of the active

Part.

Cross-section Variable

management (open with click on

the drop down menu) and display of

the active variable OR input filed of

VALUES for drawing the

construction lines.

Layer-Function to

draw elements in

different layers.

Predefined position of the Part

1 (intersection point of CL1

and CL2) marked with flag

and number.

Dif

fere

nt

Zoo

m F

un

cti

on

s.

Figure 4-4: Input window for cross-section definition.

Note: Those buttons which have a small arrow in the lower right corner (see button for construction lines, reference points, etc.), have sub menus with additional features that can be accessed by right clicking.

Figure 4-5: Move the mouse over the button with the arrow icon and right click.

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4.2 Definitions

4.2.1 Construction Lines (CL)

Construction lines have to be defined to create a series of intersection points that will be

used to define the FE-Elements which are needed for the Cross-section FE-Mesh. There

are several different ways to draw the construction lines. The type of the construction

line is selected from the sub menu for the construction lines (see Figure 4-5). Each con-

struction line (labeled CL_[+continuous number]) is drawn in relation (e.g.: parallel to

one line with a certain distance, line through intersection point of two other lines with

certain angle or slope, line defined with two intersection points, etc.) to, at least one

other already existing construction line. At the begin this is one of the two default con-

struction lines CL1 and CL2. Ultimately all construction lines are dependent on the two basic construction lines CL1 (horizontal) and CL2 (vertical) and so also the cross-

section is related to them.

Note: The different relations between the construction lines play a very important role in the consider-

ation of the variable dimensions of the cross-section along the axis. The assignment of a variable

to a certain construction line and station values assigned to that variable via table or formula

will affect also all other construction lines that are somehow dependent on that construction line.

4.2.2 Cross-section and Axis

The default positions of the basic construction lines CL1 and CL2 define the coordinate

system of the cross-section, where CL1 (horizontal line) is the Z-Axis and CL2 (vertical

line) is the Y-Axis. The intersection point of these construction lines represents the con-

nection between the axis and the cross-section.

Note: By the definition of the Offset (selecting the line and clicking on the modify button), the position of the cross-section relative to the axis (intersection point of CL1 and CL2) changes.

4.2.3 Cross-section

The geometry of a cross-section is defined by connecting intersection points of con-

struction lines to outline the cross-section elements. Each cross-section is partitioned

into elements.

Note: Into account has to be taken the fact that, at the definition of the (asymmetrical) cross-section

in Modeler, the cross-section is displayed against the axis direction.

4.2.4 Cross-Section Elements

Cross-section elements are constructed by connecting intersection points of CLs. An element comprises a two-dimensional, three or four-sided polygon enclosed by the in-

tersecting CLs. The sides of the cross-section elements must not overlap. The direction of input has no influence on the result.

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4.2.5 Parts

Elements of the cross-section with different properties are grouped into parts. For ex-

ample, these parts can be used for composite cross-sections. In the current example the

cross-section consists of one part. When defining composite cross-sections the elements

for concrete and elements for steel are assigned to different parts (one part for concrete

elements and another one for steel elements).

Note: The parts are also used for the definition of two or more beam (elements) series in one cross-

section. E.g.: A double T-Cross-Section; Instead of preparing two cross-sections (in each one

T) and creating two segments (for that two axes are needed) only one cross-section with two parts and one segment (one axis) has to be prepared.

In this example only one part is used because there is only one hollow cross-section

made of concrete and only one beam (element) series needed.

4.2.6 Reference-Sets

Certain points within the cross-section such as reinforcement points, stress check points

and temperature points are assigned via Reference-Sets with corresponding type.

4.2.7 Layer

One or more layers can be assigned to each object (construction line, FE-Element, di-

mension, Reference-Set, etc.) and can be displayed or not (define a certain layer(s) visi-

ble or not).

4.3 Definition of the Construction Lines

For the definition of this hollow box cross-section 10 vertical, 7 horizontal and 4 in-

clined construction lines are needed.

Firstly, two new vertical CLs will be constructed which have an offset of 252 in. (21 ft.) from the center (the reference line will be the basis vertical line, CL2). Note that if

you would prefer to work in units of ft. for defining the cross section, you can make this

change by going to File>Change Project Settings.

Enter the offset value of 252 directly in the variable field (Figure 4-7). This offset value will be used for all other operations on CLs until it is changed or a variable is selected from the variable list.

Click the parallel translation button. If another type of construction line is se-lected, this has to be changed as is shown in Figure 4-5.

Figure 4-6: Crosshair before (left) and after (right) selection of any drawing command.

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Note: After selecting a button (command) the crosshair changes from dashed to solid. (see Figure 4-6).

A command can be deselected by right clicking or hitting Esc.

In the command line at the left bottom side of the window, the required input action is

displayed for the selected command. For this command, Parallel: Choose reference line by clicking it is displayed

Click on the vertical base construction line (CL2) as a reference line.

Note: The selected reference line will now be shown highlighted.

Click on the left side of the axis where the new CL with an offset of 252 inches should be placed.

The command line displays: Parallel: Click on side of the reference line to specify the direction.

Click anywhere on the left side of the construction line.

A new construction line at a distance of 252 in. from the vertical base line is drawn.

Note: The constant value (defined in the field on the bottom right side) can be changed all the time even when the command is active.

Using the same principle the line on the other side can be constructed.

Note: The selected command (Parallel translation) remains active and need not be selected again. The

same applies for the defined value. This doesnt apply for the selected reference line.

Click on the vertical basis line to select the reference line. Click somewhere on the right side of the selected reference line.

A new vertical construction line with an offset of 252 in. from the vertical base line is

created.

The two generated construction lines are shown in Figure 4-7 together with the required

input scheme.

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Figure 4-7: Construction line input screen with first two new CLs.

Next, two more construction lines parallel to the previously generated construction lines

with an offset of 120 in. towards the vertical basis construction line (CL2) have to be created.

Change the parameter in the space next to Constant to 120.

Select the parallel translation button . Click onto the first new CL (see Figure 4-7) as the reference CL. Click on the right side of the first new CL Construct the next CL similarly but use the second new CL as a reference line. Note: Since there is no variable dependence, these two lines could be constructed with a distance 132

in. from the vertical base line. The same applies for all other subsequent vertical construction

lines.

Using the same principle all other vertical lines can be defined.

Selection of the command

'Parallel translation' from the

menu for construction lines

Drawn construction lines

Selection of the vertical

base line as reference line

Instructions for the

selected command

Direct definition of the value

(offset) in the field for constants

First new CL

Second new CL

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Construct two more CLs in the same way with an offset of 36 in. on each side of the vertical base line (see Figure 4-8).

Construct two more CLs in the same way with an offset of 99 in. on each side of the vertical base line.

Construct two more CLs in the same way with an offset of 54 in. on each side of the vertical base line.

Definition of horizontal construction lines follows the same principle.

Construct three horizontal CLs parallel to the horizontal basis construction line (CL1) with distances of 9 in., 9 in. and 180 in. The lowest line (having a total dis-tance of 16.5 ft. from CL1) corresponds with the maximum depth of the cross-section

and determines the inclination of the web.

The screen for the cross-section definition should now be as shown in the figure below.

252 252

120 120

54 54

99 99

132 132

9 9

180

36 36

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Figure 4-8: Construction line input screen with required construction lines and element points.

Note: To facilitate the selection of specific construction line, the zoom functions or freehand symbols

(see the note in chapter 2.3) can be used. These can be used any time during construction.

If two or more construction lines are positioned in the crosshair square at the moment of selec-

tion of the reference line (more than two construction lines at selection of an intersection point)

a window opens where one of the construction lines has to be specified. The line can be selected

in this window or the window is exited with Esc and the construction line (or intersection point) is explicitly selected.

Each selected and active command can be exited by clicking on the Esc (keyboard) button or by right clicking.

With the undo button (above the toolbar for zoom functions) the last drawn element (construc-

tion line, FE element, reference point, etc) can be deleted.

To delete any incorrectly created construction line, first make sure that no drawing command is

active (the crosshair is dashed). Then select a construction line. It will be displayed in orange,

and extra icons for editing the corresponding line, including the icon for deleting, appears above

the toolbar for zoom functions.

See also section 4.5 for a detailed description of editing elements in the cross-section window.

In order to create the variable for the variation of the web thickness correctly a new

construction line defining the slope of the web is required. It can be created using two

already existing intersection points.

Click on the 2 intersection points button in the toolbar for drawing construc-tion lines (see the Figure 4-5).

Draw the two construction lines by clicking the respective intersection points (see Figure 4-9) for the definition of the web outline (as per instructions in the com-

mand line).

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Figure 4-9. Construction line input screen with outside shape of web.

Note: The inclination of the web is defined by the intersection points shown in Figure 4-9. These con-

struction lines represent the outer edges of the webs. The inner edge of the web has the same in-

clination and defines the web thickness which is variable along the station. This variation (vari-

able) will be defined in next few steps in the same way as the variation of the cross-section

height and the bottom slab thickness. The lower outer edge of the cross-section (outer edge f the

bottom plate) also varies due to the variation of the cross-section height the constant horizon-tal construction line (5 m from the horizontal base line) serves only to define a constant web in-

clination.

One of the variable dimensions in this cross-section is the height which varies along the

bridge axis. The corresponding CL in the cross-section must be identified as a variable.

Once a variable is created a dummy dimension is assigned so that the construction line

can be drawn and the cross-section construction can continue. A table defining the

depth variation will be defined later, and it will be combined with the variable (the

dummy will be replaced by the table values).

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By clicking on the drop down menu next to the input window for constants (val-ues) a new window opens. The first time you click it (no variable is defined yet)

a window for the definition of a new variable opens.

Figure 4-10: Definition of a variable h_cs.

Set h_cs for the name of the new variable, assign a dummy value for the basic

cross-section shape (138 in.), select length and confirm with OK .

Note: The name should not include and mathematical operators (+,-,/ or *)

The entered value is needed only to draw the construction line with assigned value. The actual

values to be used will be assigned later on.

It is possible to define a variable with type Angle. In that case the values to be defined via table or formula are angles (in degrees or radians) or slopes (inclination in percentage).

Using the input filed expression, variables can be defined as functions of other variables or expressions using internal variables (see section 5.6 in RM Analysis User Guide).

The field Description is used for more detailed description. This is recommended to be used if the

name of the variable is not clear enough and if there are many variables.

The new variable appears in the variable list for the current cross-section.

Hit Activate to take the new variable h_cs as the current active variable. The vari-able appears in the variable input field.

Figure 4-11: Definition of a variable h_cs.

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The selected variable is now, together with the assigned dummy value, active.

Now the construction line for the variable cross-section

height can be constructed.

With parallel translation create a new horizontal line. The reference line is the basis horizontal line (CL1) and the side to specify the direction is below CL1 (see also

Figure 4-13).

Instead of a constant value for the distance between the reference line and the created

line, this variable will be used.

Note: This variable remains active until a new variable is (created and) activated or a new constant

value is defined (directly in the input field).

Using the same principle the other two variables (with dummy values) can be created one variable for the variation of the web thickness (d_web=28) and another for the variation of the bottom slab thickness (d_bot=14) and used to create two new variable construction lines

In addition, for the haunches in the bottom plate, another construction line has to be drawn. This line has to be defined parallel to the inner edge of the bottom slab with

the distance of 6 in. to the inside.

The Figure 4-12 shows the list of created and used variables, and Figure 4-13 shows the

created construction lines

Figure 4-12: Definition of all variables.

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Figure 4-13: Definition of all variable construction lines.

Using these principles the definition of the constant and variable construction lines is

finished.

4.4 Cross-Section Elements

Once the construction line definition is completed, the cross-section elements can be

entered.

Activate the element definition by selecting the symbol for the definition of 4 node elements.

Click on four intersection points (defined by the construction lines), one after another to define the element.

First the left part of the left hand cantilever as shown in the figure below, will be defined. The newly defined element is displayed on the screen, and the part number

(number 1 in this case) is shown at the centre of the element.

Note: To define a triangle, the last (fourth) element point has to be the same as the first one the first element point has to be (at the end) selected once more.

h_cs

d_web d_web

d_bot 6

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Figure 4-14: Element definition based on intersection points of construction lines.

All other elements are defined in a similar way. The element button must be selected again to define the next element if the cursor has become inactive (shown dotted). If

the cursor is still active then re-selection of this button is unnecessary.

In order to identify the correct points it is often necessary to zoom in and out of the screen plot.

In the event of input errors delete the erroneous element by using the delete button as explained above (in the 6

th note). Elements can be identified by clicking on the corre-

sponding part-number.

In total 14 elements are required in this example. The final cross-section is shown in the

Figure 4-15.

Note: To facilitate the selection of specific elements, the zoom functions or freehand symbols (see the

note in chapter 2.3) can be used. These can be used any time during construction.

If two or more construction lines are positioned in the crosshair square at the moment of selec-

tion of the reference line (more than two construction lines at selection of an intersection point)

a window opens where one of the construction lines has to be specified. The line can be selected

in this window or the window is exited with Esc and the construction line (or intersection point) is explicitly selected.

1

2 3

4

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Each selected and active command can be exited by clicking on the Esc (keyboard) button or by right clicking.

With the undo button (above the toolbar for zoom functions) the last drawn element (construc-

tion line, FE element, reference point, etc) can be deleted.

To delete any incorrectly created construction line, first make sure that no drawing command is

active (the crosshair is dashed). Then select a construction line. It will be displayed in orange,

and extra icons for editing the corresponding line, including the icon for deleting, appears above

the toolbar for zoom functions.

See also section 4.5 for a detailed description of editing elements in the cross-section window.

Figure 4-15: Completed element definition.

4.5 Editing in the Cross-Section window

4.5.1 Object selection

Before selecting any object, be sure that no drawing command is active the cross hair is dashed and there is no message in the command line.

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Now any object can be selected by clicking on it with the cross hair. To select a con-

struction line no other object can be within the square of cross hair at the time of selec-

tion. It is the same for selecting an element click somewhere within the element so that no other object (construction line, reference point, etc.) is positioned within the square

of cross hair.

If there are more objects within the cross hair square (the selection isnt clear) a window opens where one of these objects can be specified.

It is also possible to select multiple objects at the same time. For that the Shift button has to be clicked (and held) during the object selection. If multiple objects are selected,

the detailed modification (see description below) is no longer possible. It is possible to

delete them, modify the color and change the layer assignment only.

In the short description of the Cross-section window (Menu HelpBrief Help for Icons submenu Cross section) at the bottom left side there is a description of the shortcuts to access the lists of certain object groups (e.g.: Ctrl+C opens the list of ex-isting construction lines). In these lists (windows) it is possible to select any object(s) by

clicking the Space button.

To deselect objects that have been selected, simply click somewhere in the blank area in

the cross-section window. The same effect is achieved if a new object is selected or a

new drawing command is chosen.

When a particular object is selected it becomes highlighted and additional buttons (but-

ton for editing, button for color selection, the delete button and other object specific

buttons) appear above the toolbar for zoom functions.

4.5.2 Construction line editing

If only one of the construction lines is selected additional buttons appear as explained

above. These are:

- Color button: for changing the color of the line

- Change side button: for changing the side of the reference line

- Edit button: editing the construction line parameters

- Delete button: deleting the selected construction line (if this line is a reference line for other objects, the line cannot be deleted)

By clicking the edit button a window opens as is shown in Figure 4-16.

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Figure 4-16: Editing selected construction line.

Name Name of the construction line (default: CL_[continuous number])

Type Indication of the creation type; Cannot be changed

Variable

Indication of used variable by clicking on the drop down menu next to the input field, the variable can be changed (selection is pos-

sible between the created variables) or set as constant (same follows

vice versa).

Distance

Used value (distance for parallel displacement, angle ), which can be changed. The value set by the variable it cannot be changed here,

but only in the variable list.

References

The reference being used for the definition (e.g.: Reference line,

intersection point, etc.). By clicking the Change button it can be interactively changed.

1. Selected construction line

3. Additional

buttons appear;

4. Click the

edit button

2. Reference line is shown 4. Edit window opens

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Extendet to -/+ infinity Trimming of construction lines; Can be defined subsequently.

Left/Right Side of the construction line; Can be changed.

Extended

Color The color can be changed also here.

Line type The type of the line (dashed, dashed-dotted, etc.) can be changed.

Line width The line width can be changed.

4.5.3 Editing of FE-Elements

Additional buttons appear above the toolbar for zoom functions if an element is selected

similar to when a construction line is selected. The only difference is that there is no

button for changing the side.

Clicking the edit button will open a window for element editing, as is shown in figure

below.

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Figure 4-17: Editing selected FE-Element.

Name: Element name (Default: EL_ continuous number).

Part: Assigned part. If more parts exist, another part can be assigned.

Shear lag

property

Definition of shear lag for shear in the vertical and horizontal di-

rection for selected element. In addition the shear lag factors for

both shear components and torsion can be defined.

Rounding of element edg-

es For each element edge a radius can be defined.

Element refinement

With the reference to the starting point (displayed in the small

window with another color) different automatic element mesh

refinement can be activated.

FEM Options Possible only if FEM elements are used for the construction of the

cross-section (see the training example for FEM).

Extended

Color Changing the color of the element.

Line type Changing the line type with which the element edge is drawn.

Line width Changing the line width with which the element edge is drawn.

Dependency Each intersection point (of two construction lines), which defines

the position of the element node, can be changed.

4.6 Definition of Reference-Sets

Additional geometric and static information is needed for the reinforcement calculation

and fiber stress checks later on in the Analyzer. This is done by preparation of certain

definitions directly in the cross-section.

Also the geometric position for the connections of different segments and spring ele-

ments (e.g. Piers, Abutments, Columns, etc.) must be defined in the cross section.

The definition of these additional objects is done via Reference-Sets.

There are different types of Reference-Sets based on their use (e.g. Bending reinforce-

ment, Shear reinforcement, Stress points, etc).

First the general properties of the Reference Sets are defined and grouped together.

Then they are drawn in the cross-section in the form of individual points, lines and pol-

ygons. These drawing objects are drawn according to certain rules. They can be defined

at an intersection point of two construction lines, relative to an FE-Element node or

edge, etc.

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4.6.1 Attribute sets

In addition to Reference-Sets, Attribute-Sets have to be assigned to all Reference-Sets

for the definition of reinforcement. Using these Attribute-Sets the material is assigned to

certain Reference-Sets. (Also the post-processing of the reinforcement calculation is

done via these Attribute-Sets all results of the reinforcement calculation are saved to the Attribute-Sets, not the Reference-Sets).

Note: For example, it is possible to define the reinforcement in the top plate over both webs (in a hol-

low box cross-section) in two different reference sets but to combine them in one Attribute-Set

and so obtain a total result for the reinforcement amount in the top plate.

4.6.2 Reference-Sets Basic input description

Before continuing with the example, basic input principles for the definition of a Refer-

ence-Set will be explained. Figure 4-18 shows the input window for the definition of a

new Reference-Set. Below that Figure there is a detailed description.

Figure 4-18: Definition of a new Reference-Set.

Name: The name of the Reference-Set

Typ: Selection of the type of the Reference-Set to be created

Part: Assignment of a Reference-Set to a part (here only one part (1); to be considered

in multi-part cross-sections and composite cross-sections)

Attribute-Set: Name of the Attribute-Set where the Reference-Set is assigned.

A new one is created by selection of the create button; an existing one is select-ed from the drop-down menu.

Attribute-Sets can have the same name as Reference-Sets.

Material: Selection of the material to be assigned to the Attribute-Set.

Once an Attribute-Set is selected, the selection window for the Material becomes

active and the Material to be assigned can be selected from the drop-down menu.

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Type Application

Connection points Definition of the position of connection points for segments and

spring elements (bearings).

Stress check points Definition of the points in the cross-section in which normal stress-

es should be calculated and checked (Fib action in Analyzer). Addi-

tionally may be used as geometry points (see below).

Geometry points Definition of a (geometry) position in the cross-section as a refer-

ence position (e.g. reference point for the definition of the tendon

position).

Temperature points Definition for non-linear temperature gradient.

Bending reinforcement Definition to determine the longitudinal reinforcement for the

Bending design with Axial force (check action UltRein).

Cracking reinforcement Definition to determine the longitudinal reinforcement due to the

Crack control (check action Crack).

Robu reinforcement Definition to determine the longitudinal reinforcement due to the

Robustness check (check action Robu).

Torsion reinforcement Definition to determine the torsion reinforcement due to torsion

(check action Shear).

Shear-long reinforcement Definition to determine the longitudinal reinforcement due to shear

and torsion (check action Shear).

Shear reinforcement for web Definition to determine the web reinforcement due to shear (check

action Shear).

Shear reinforcement for flange (Qy) Definition to determine the shear reinforcement in flange due to

longitudinal and transversal shear forces. Shear reinforcement for flange (Qz)

Longitudinal reinforcement Includes different types of longitudinal reinforcement: Bending

reinforcement, Cracking reinforcement and Robu reinforce-

ment.

Table 4-1: Types of Reference-Sets.

4.6.3 Creating a Reference-Set for Stress check points

Only two stress check points will be created one in the middle of the top edge of the top plate and one in the middle of the bottom edge of the bottom plate.

By clicking on the arrow near to the display window for Reference-Sets a new window for the definition of a new Reference-Set opens.

Note: If there is one or more Reference-Sets already created a list of created Reference-Sets opens

when clicking on this arrow.

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Figure 4-19: Definition of the Reference-Sets of Type Stress check points named Stresses-MG.

To define a Reference-Set for the definition of the stress check points (see Figure 4-19) a name of the reference set has to specified and the type (Stress check points)

selected from the drop down menu. The reference set is assigned to Part 1 (there is

only one. In the case of more parts, the correct part number has to be defined). Be-

cause this is not a Reference-Set for the definition of reinforcement, no Attribute-Set

has to be created and assigned.

The input is accepted by clicking on Ok .

Now a window opens (see Figure 4-20) where all defined Reference-Sets are listed (cur-

rently there is only the one which was created in previous step). Here new reference sets

can be added (clicking on the insert after button ) and existing ones can be modi-

fied (clicking on the modify button ). For further geometric definitions in the cross-

section window the particular Reference-Set has to be selected and activated.

Figure 4-20: List of created Reference-Sets.

To proceed with the definition of the stress check points select the created Reference-Set and activate it by clicking Activate . The activated Reference-Set can be also seen

in the display window for Reference-Sets .

Now the stress check points can be defined using the corresponding function for draw-

ing reference points (See Figure 4-4).

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Click on the function Reference point at an intersection point in the menu for drawing reference points. In the command line Reference point (intersection): Click an intersection point of two construction lines is displayed

To create a point at the top edge and in the middle of the top plate, click on the inter-section point of the construction line CL_1 and CL_2 (see Figure 4-21).

Figure 4-21: Position of the stress check point.

After selecting the particular intersection point a new window opens.

Figure 4-22: Definition of the stress check point.

Name: Name of the reference point

Type: Type of the reference points (Single point, Line, Curve)

Checkbox Activate local refinement

Activating this option will automatically refine the FE-Element in which the

point is located.

Input according to the Figure 4-22 (SP-T which stands for stress point top)


Now the stress point is graphically displayed in the cross-section.

Using the same principle, the stress point (SP-B) in the middle of the bottom plate at the bottom edge is created. There is no need to create a new reference set for this

point the new stress point (SP-B) should be assigned to the same one.

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This second stress check point is also the last one created in this example. Of course

more stress points at different position could be created. The cross-section should now

look like as shown in the picture below.

Figure 4-23: Stress points (SP-T and SP-B) in the cross-section.

4.6.4 Reference-Sets for non-linear temperature gradient

In the following steps Reference-Sets of type Temperature points should be created and can be used as explained in Table 4-1, for non-linear temperature gradients.

The non-linear temperature gradient is done according to AASHTO 3.12.3. The struc-

ture is assumed to be in temperature zone 3, thus the values for T1 and T2 are given in

table 3.12.3-1. T3 is assumed to be zero, and the multiplier for negative temperature

gradient is 0.3. The table and sketch below show the temperature points and their loca-

tions.

Temperature Points:

Temperature Gradient

Point Positive (oF) Negative (

oF)

T1 41 -12.3

T2 11 3.3

T3 0 0

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The construction line for creating T1 is the top of the cross section, but two new

construction lines will have to be created for the location of T2 and T3. Create two new

construction lines with offsets from the top of the cross section of 4 in. and 16 in. Next,

create a new Reference Set:

Define a new Reference-Set for the Temperature points in Figure 4-25

Figure 4-24: Reference-Set for positive non-linear temperature gradient.

To proceed with the definition of the temperature points select the created Ref-erence-Set and activate it by clicking Activate . The activated Reference-Set can

be also seen in the display window for Reference-Sets.

Now the temperature points can be defined using the corresponding function for draw-

ing reference points (See Figure 4-4).

Click on the function Reference point at an intersection point in the menu for drawing reference points. In the command line Reference point (intersection): Click an intersection point of two construction lines is displayed

To create a point at the top edge and in the middle of the top plate, click on the inter-section point of the construction line CL_1 and CL_2 (see Figure 4-21).

After selecting the particular intersection point a new window opens.

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Name: Name of the reference point

Type: Type of the reference points (Single point, Line, Curve)

Checkbox Activate local refinement

Activating this option will automatically refine the FE-Element in which the

point is located.

Input according to the picture above.


Now the temperature point is graphically displayed in the cross-section.

Using the same principle, three more temperature points will be input for TempPlus. T2-P will have a temperature difference of +11. T3-P will have a temperature differ-

ence of 0, and a temperature point must be placed at the bottom of the cross section

also with a temperature difference of 0.

After creating these 4 temperature points, open the Reference set dialogue box, high-

light TempPlus, and click the Curve button. The following will be displayed:

To create the negative temperature gradient, a new Reference Set will have to be creat-

ed.

Following the steps for TempPlus, create a new Reference Set called TempMinus and

insert the points for the negative temperature gradient. The curve will look as follows:

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4.6.5 Reference-Sets for longitudinal reinforcement

In the following steps Reference-Sets of type Longitudinal reinforcement should be created which can be used, as explained in Table 4-1, for bending moment design, crack

check and robustness check.

Note: Instead of three separate Reference-Sets for each design check only one needs to be defined.

However, this will affect also the post processing of the reinforcement calculation the results from the different checks will be summed up into one reinforcement result (amount). If the re-

spective individual reinforcement results are of interest, separate Reference-Sets of the corre-

sponding type have to be defined.

Two Reference-Sets of type Longitudinal reinforcement will be created - one for the reinforcement in the top plate and another one for the reinforcement in the bottom plate.

It is important that each of them (top and bottom reinforcement) is assigned to its own

Reference-Set (of the same type) respectively and Attribute-Set. Doing this will ensure

they are treated separately in the calculation (two different Reference-Sets/Attribute-

Sets means two different reinforcement results).

As mentioned already above, Attribute-Sets can have the same names as Reference-

Sets, but this is not required.

Define a new Reference-Set for the reinforcement in the top plate as is shown in Fig-ure 4-255 (see also 4.6.2)

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Figure 4-255: Reference-Set for the longitudinal reinforcement in the top plate.

Now the geometric definition for this Reference-Set can be done. For that a line over

the whole width of the cross-section will be created. This line represents the center of

gravity of the longitudinal reinforcement in the top plate.

To create this line, two reference points have to be created. To create first one, click on the Reference points button and select Reference point relative to an elements

node . You may have to right click the other button Reference point at an inter-section to get to it.

In the command line it says Click the element node, and in the cross-section all element nodes becomes visible.

Note: Each FE-Element is a 9 nodded isoparametric element. The nodes on the element edges (total 8

nodes) are displayed as small dots. The ninth node is in the middle of the element and is dis-

played as a (part) number.

Click the top left corner of the left cross-section cantilever as the start point of the reference line for the reinforcement in the top slab (see Figure 4-266).

Figure 4-266: Selection of the reference point starting point of the reference line.

After the selection of the node a new window opens where the name, type and eccentri-

cities have to be defined. Usually there is no need to define the name of this reference

point. On the other hand the eccentricities (relative to the selected element node) in the

vertical (Y) and transversal (Z) direction have to be defined, except when the point is

exactly at the reference node. The type of this starting point is Single point and is se-lected by default.

Define the eccentricities as is shown in the Figure 4-277.

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Figure 4-277: Definition of the starting point of the top reference line for longitudinal reinforcement.

To confirm the input click Ok . Now the starting point is displayed graphically.

The second point is created in the same way at the end of the cantilever on the right side of the cross section. The eccentricity DZ will be negative this time. Also, the

type becomes LINE TO so that it is connected to the previous point (see Figure 4-288).

Note: The command remains active and it doesnt have to be selected once more.

Figure 4-288: Definition of the end point of the top reference line for longitudinal reinforcement.

Once the definition of the end point is finished, the reference line for the reinforcement

in the top plate is graphically displayed.

Note: The biggest difference between this and first point is in the point type the type of the second point is Line. This means that there will be a line created from the previous point to this one. After the selection of the node, the program automatically changes (recommends) the type of the

second reference point.

Figure 4-299: Graphical display of the reference line for the reinforcement in the top plate.

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Using the same principle the reference line for the reinforcement in the bottom plate has

to be defined.

Note: The drawing action for the definition of reference points remains active after the definition of the

new Reference-Set.

After the selection of the reference node for the first point of the line for the reinforcement in the

bottom slab, the programs automatically changes the type of the reference point back to

Point. After selection of the second point, the same happens as before the program once again automatically changes the type of the reference point from Point to Line.

The order of the point selection does not matter. Same applies for the point names.

Figure 4-30: Definition of the Reference-Set for the definition of the reinforcement in the bottom plate.

Figure 4-301: List of the defined Reference-Sets.

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Figure 4-312: Definition of the starting point of the reference line for reinforcement in the bottom plate.

Figure 4-323: Definition of the end point of the reference line for reinforcement in the bottom plate.

Figure 4-334: Cross-section after the definition of the longitudinal reinforcement.

4.6.6 Reference-Sets for shear reinforcement

For the calculation of the shear reinforcement three Reference-Sets will have to be cre-

ated. However, in total two different Reference-Set types have to be used Shear rein-forcement for web and Shear longitudinal reinforcement (see Table 4-1).

Using the Reference-Set of type Shear reinforcement for web the position, number and geometry (web inclination and thickness) of the web is defined. For each web an

individual Reference-Set has to be defined and used to create a line in the middle of the

web. From the number of reference sets the program gets the information on how many

webs the cross-section has, and from the line orientation it gets the inclination of the

web.

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Figure 4-345: Definition of the median line of web sections.

As shown in Figure 4-345, this reference set has to contain 2 points defining a straight

line within the web representing the respective web. However, the specified line must

always be within the web, because the program searches the next boundary line on the

left and on the right side for calculating the proper web width.

The shear check for the individual webs requires an additional reference set to be speci-

fied defining the total depth in the cross-section, where cuts across any webs should be

investigated (see Figure 4-356). This reference set is of the type Shear longitudinal reinforcement, and not related to the individual web sections, but to the total cross-section. It is also used for storing the required additional longitudinal reinforcement due

to shear force.

Figure 4-356: Sector for investigating cuts across the webs.

Also, all these References-Sets have to be assigned Attribute-Sets each Attribute-Set has to be assigned to only one Reference-Set. Using this principle the results from the

reinforcement calculation will be saved properly.

Define two new Reference-Sets of type Shear reinforcement for web named Shear-Web-L and Shear-Web-R and one Reference-Set of type Shear Longitu-dinal Reinforcement named Shear-Long as is shown in following pictures.

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Figure 4-367: Definition of the Reference-Set for the reinforcement in left web.

Figure 4-378: Definition of the Reference-Set for the reinforcement in right web.

Figure 4-389: Definition of the Reference-Set for the shear longitudinal reinforcement.

Figure 4-40: List of the Reference-Sets defined until this point.

Before the definition of the reference points and lines, the correct Reference-Set has to be activated.

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Activate the reference set for the reinforcement in the left web Shear-Web-L and then (in the window for the cross-section definition) select the command Refer-ence point relative an elements node. Define the reference points as is shown in figures below.

Figure 4-391: Definition of the begin point of the line for the definition of the reinforcement in web.

Figure 4-402: Definition of the end point of the line for the definition of the reinforcement in web.

Selecting these points will define a line in the middle of the web, and it will remain in

the middle even when the web thickness changes. Now Activate the Reference-Set for

the definition of the reinforcement in the right web and use the same approach for the

definition.

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Figure 4-413: Reference lines for the reinforcement in webs.

Note: The order of the point selection does not matter.

Now the Reference-Set Shear longitudinal reinforcement has to be defined. First it has to be activated. Unlike before, the reference points will refer to the intersection

points of two construction lines.

Activate the Reference-Set Shear-Long and chose the command Reference point at an intersection point.

Define the upper boundary line as is shown in the pictures below the start point will be defined at the left web and the end point will be defined at the right web.

However, the order does not matter.

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Figure 4-424: Definition of the upper boundary line.

Using the same method the bottom boundary line has to be defined.

Note: For both boundary lines, top and bottom, the same Reference-Set has to be used.

The type of the start point of the bottom line has to be Point and is not changed automatically it is necessary to change it manually.

Figure 4-435: Defined bottom boundary line.

4.6.7 Reference-Sets for torsion reinforcement

An additional Reference set has to be defined for the calculation of the torsional rein-

forcement. This Reference-Set is of type Torsion reinforcement.

The calculation of the torsional resistance is based on the theory for thin-walled closed

sections. Therefore, for any actual cross-section, an equivalent single cell hollow box (see Figure 4-446) has to be defined by the user, which allows for performing the shear

capacity check with respect to torsion. This is done by geometrically defining the medi-

an line (perimeter line uk) of the effective hollow-box cross-section by specifying an

additional reference set of the type Torsion reinforcement (see Table 4-1).

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Figure 4-446: Effective single cell hollow box cross-section for torsion.

The same perimeter line is used for the calculation of both the shear resistance of the

concrete and the shear resistance of the torsion reinforcement. In the case of hollow box

cross-sections, where the torsion reinforcement is usually placed on both sides of the

affected webs, the perimeter line will mostly be placed along the centre lines of the ac-

tual web and slab parts forming the effective hollow box.

Create a new reference set of type Torsion reinforcement and corresponding At-tribute-Set with assigned material.

Figure 4-457: List of created Reference-Sets and assigned materials via Attribute-Sets.

Activate the created Reference-Set and select the drawing command Reference point relative to an elements node.

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Figure 4-468: Definition of the start point (left) and second point (right) for the definition of the perime-

ter line for torsion reinforcement.

It is very important and crucial that the start point of the reference line for torsional re-

inforcement is also the end point this means that the same position has to be selected for the start and end points.

Figure 4-479: Finished perimeter line for the torsion reinforcement.

4.7 Definition of the Pier Cross-Section

The cross-section of the two piers will be defined in the same way as the main girder

cross-section. The first step is to create a new empty cross-section called Pier under Cross-Section in the navigation tree.

Start with the definition of construction lines, then element definition, and finally the specificati

GP E Prestressing Basic AASHTO Imp

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