RM E Prestressing Basic Part1 AASHTO

RM Bridge Professional Engineering Software for Bridges of all Types

RM Bridge V8i

December 2011

TRAINING PRESTRESSING BASIC

ANALYZER PART 1: AASHTO

RM Bridge

Training Prestressing Basic ANALYZER Part 1: AASHTO I

Bentley Systems Austria

Contents

1 General ................................................................................................................... 1-1

1.1 Starting the Program ...................................................................................... 1-1

1.2 Subjects Covered in this Training .................................................................. 1-1

2 General Example Data ........................................................................................... 2-1

2.1 Structural Model ............................................................................................ 2-1

2.2 Cross-Section ................................................................................................. 2-4

2.3 Substructure ................................................................................................... 2-6

2.4 Pre-Stressed Tendon Layout for Internal Tendons ........................................ 2-7

3 Lesson 6: Analyzer ................................................................................................ 3-1

4 Lesson 6: Tendon Definitions ................................................................................ 4-3

4.1 Tendon Material Import ................................................................................. 4-3

4.2 Definition of Tendon Groups ......................................................................... 4-4

4.3 Assign the Tendon Group to the Elements .................................................... 4-5

4.4 Definition of the Cable Geometry ................................................................. 4-6

4.5 Definition of the Tendon Stressing Schedule ................................................ 4-9

5 Lesson 7: Load Management ................................................................................. 5-1

6 Lesson 8: Load Definitions .................................................................................... 6-3

6.1 Definition of Load Cases for Self Weight ..................................................... 6-3

6.2 Definition of Load Cases for the Additional Loads ....................................... 6-5

6.3 Definition of Load Cases for the Tendons ..................................................... 6-6

6.4 Definition of Load Cases for the Creep and Shrinkage Effects ..................... 6-7

7 Lesson 9: Definition of Construction Stage 1 ........................................................ 7-1

7.1 Creation of construction stages ...................................................................... 7-1

7.2 First construction stage .................................................................................. 7-2

7.2.1 Activation ................................................................................................... 7-2

7.2.2 Schedule actins calculations ................................................................... 7-2

8 Lesson 10: Definition of Construction Stage 2 ...................................................... 8-1

8.1 Element Activation ........................................................................................ 8-1

RM Bridge

Training Prestressing Basic ANALYZER Part 1: AASHTO II


8.2 Calculation (Static) ........................................................................................ 8-1

9 Lesson 11: Definition of Construction Stage 3 ...................................................... 9-2

9.1 Element Activation ........................................................................................ 9-2

9.2 Calculation (Static) ........................................................................................ 9-2

10 Lesson 12: Definition of Final Stage (Creep) ...................................................... 10-3

10.1 Calculation (Static) ...................................................................................... 10-3

11 The Calculation .................................................................................................... 11-4

11.1 Calculation options ...................................................................................... 11-4

11.2 Special settings ............................................................................................ 11-5

12 Result presentation ............................................................................................... 12-7

12.1 Possibilities in presentation of results .......................................................... 12-7

12.2 Diagram creation via RM-Sets .................................................................... 12-8

RM Bridge

Training Prestressing Basic ANALYZER Part 1: AASHTO 1-1


1 General

The understanding of basic definitions and concepts as given in the Getting Started ex-

ample is assumed in the following example.

The principles shown in the Getting Started example for Modeler and Analyzer:

Defining the structural model

Defining a tendon geometry

Defining loads

Defining a traffic loading case

Defining a construction schedule

Running the calculation

Viewing the results

Fiber stress check

Ultimate load check

Shear capacity check

1.1 Starting the Program

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

lation procedure automatically creates the following icon on the desktop:

To start the program, use the desktop icon or select the icon from the Windows Start

menu at All Programs, Bentley.

1.2 Subjects Covered in this Training Detailed modeling in Modeler (temperature points + pier and support condi-

tions).

Load definition for three construction stages.

Traffic loading case definition in accordance with AASHTO.

Construction schedule definition for the three construction stages.

Making the structural analysis.

Calculation result viewing.

Fiber stress check.

Ultimate load check.

Shear capacity check.

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2 General Example Data

In this example, a three span bridge is presented with a hollow box girder. It is built

span by span in three construction stages.

Figure 2-1: 3D-view of the bridge.

The span lengths of the pre-stressed concrete girder are 40m, 60 m and 40m. The height

of the box cross-section is variable along the curved bridge axis.

2.1 Structural Model

40m 60m 40m

10x4m 10x4m 15x4m

A4 A1 A2 A3

20m

Figure 2-2: Structural model.

System axis: Horizontal plan

1.Part: Straight Line: Station: 0-20 m

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2.Part: Spiral: A=100, RENDE=200m: Station: 20-70 m

3.Part: Circle: R=200: Station: 70-140 m

System axis: Vertical plan

1.Part: Line: dXabsolute=65m, dZabsolute= 1.083m Station: 0-65 m

2.Part: Line: dXdifference=75m, dZabsolute= -0.2924m Station: 65-140 m

Rounding with Insert parabola by intersection R=2000m

Pier at A2:

Height: 20m (4 Elements each 5m).

Pier at A 3:

Height: 20m (4 Elements each 5m).

Numbering system:

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

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

Active elements:

Construction Stage 1: 101-113, 1100-1103, 1200-1204

Construction Stage 2: 114-128, 1300-1304

Construction Stage 3: 129-135, 1400-1403

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10x4m

40m 60m 40m

10x4m 10x4m 15x4m

A4 A1 A2

A3

40m

10x4m

A2 12m

40m 60m

15x4m

A1 A2 A3

Stage 1:

A1

Stage 2:

12m

Stage 3:

113

135

128

Figure 2-3: Construction stages.

Axis 1 Axis 2

1102

X

Z

1101

1402

1401

101-110

Axis 3 Axis 4

111-125 126-135

Figure 2-4: Support definition.

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2.2 Cross-Section

Y

Z

13,0 m

6,5 m 6,5 m

3,00 m 3,00 m

5,0 m

0,20 m

1,50m 1,50m

1,0m 1,0m

0,25m

h_cs_tab(sg)

d_bot_tab(sg) d_web_tab(sg)

0,40m

0,25m

0,90 m

4,0m 4,0m

0,40m 12,2 m

0,15 m

1,5m 1,5m

2,00 m 2,00 m

Figure 2-5: Main girder cross -section.

Node 0 Spring 1100

Node 1101 Spring 1102 Spring 1101

Y

Z

AXIS 1

2,40m 2,40m

Node 101

Figure 2-6: Definition of bearings at axis 1.

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Node 0

Spring 1400

Node 1401 Spring 1402 Spring 1401

Y

Z

AXIS 4

2,40m 2,40m

Node 136

Figure 2-7: Definition of bearings at axis 4.

1.5m

Y

Z

5.0m

Figure 2-8: Pier cross-section.

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Table 2-1: Spring constants.

Element CX [kN/m] CY [kN/m] CZ [kN/m] CMX [kNm] CMY [kNm] CMZ [kNm]

1100 1e8 1e8 1e8 1e8 1e8 1e8

1101 1e8 1e8

1102 1e8

1400 1e8 1e8 1e8 1e8 1e8 1e8

1401 1e8 1e8

1402 1e8

2.3 Substructure

seg

2

Pie

r 1

0

20m

Segment 1

Connection point

Start of segment 2

Axis 2

Connection point

1202

1203

Eccentric connection of the pier with the main girder

1204

111 seg1

1201

seg

2

Pie

r 1

Figure 2-9: Substructure Axis 2 Pier 1 (Segment2).

0

20m

Segment 1

Connection point

Start of segment 3

Axis 3

Connection point

1302

1303

Eccentric connection of the pier with the main girder

1304

126 seg1

1301

Seg

3

Pie

r 2

Seg

3

Pie

r 2

Figure 2-10: Substructure Axis 2 Pier 2 (Segment3).

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2.4 Pre-Stressed Tendon Layout for Internal Tendons

Tendon 101 Tendon 102

Tendon 103

Clearance 40cm from top

Clearance 40cm from top

Clearance 20cm from bottom



12 m 16 m

140 m

12 m 18 m 12 m

40m 40m 60 m

12 m 18 m 12 m

101 123 104 108 111 114 118 126 133 135 129

16 m 12 m

Figure 2-11: Tendon arrangement

span 1: 101 (16 tendons) Ac=16cm2, duct area Ah=50cm

2 (Nodes 101-115)


2 (Nodes 108-129)


2 (Nodes 123-136)

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3 Lesson 6: Analyzer

In the following chapters further inputs for the preparation of the project in the Analyzer

will be shown and explained.

Before continuing with the input it is recommended to recalculate the project the sys-tem which was exported to the Analyzer. This step is necessary because on the one hand

it will check the data and on the other hand it is necessary for geometry dependent in-

puts (e.g. referring to the center of gravity for the definition of the tendon geometry).

By clicking the Recalc button in the main input window (Analyzer) a new window with recalc options opens. For now only two recalc options should be activated Cross-section calculation and Structural check. However, it is possible to leave the default options. In this case you would see a warning that no stage is defined this is just information that no stage was calculated because no stage (actions) is defined.

Figure 3-1: Recalculation window

After the calculation and refreshing of the 3D View (using free hand symbols or just a

small rotation of the system) the static model in the main window is updated (eccentrici-

ties, element axis, etc). By right clicking in the viewing window, the view options (last

button in the menu) can be defined (e.g. cross-sections, element bodies, tendons, etc).

All structure data defined in Modeler and exported to the Analyzer can be seen under

Properties or Structure in the Analyzer menu tree. It is possible to modify all this data

here. However, note that after each export of the data from Modeler to the Analyzer, the

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modified structural data are overwritten. In this case all the modifications made in the

Analyzer are lost and have to be done once again if they were not saved by TCL export.

If the data/modifications were properly saved into a TCL, the TCL can be imported, and

the data will be overwritten once again. To simplify this process it is recommended that

any permanent changes to the structure are made in the Modeler.

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4 Lesson 6: Tendon Definitions

In the following chapter, the definition for the tendons will be done. In the Modeler

most of the structure definitions are already done. The only structure definition which is

missing is the specification of the tendon layouts and the corresponding stressing proce-

dure.

4.1 Tendon Material Import

To define a tendon correctly a material is needed. All material used in Modeler were

also exported to the Analyzer and are saved to the project database

(Properties Material). The Tendon material has to be imported manually.

To load the material properties go to Menu File Load Default Properties or to menu tree Configuration Load Default Properties.

A new window opens.

In this window the Materials (or Variables) are copied from the program database (left

side of the window) to the project database (right side). There are different material

groups from which a certain material can be selected and copied to the project database.

Multiple selection of material is possible by using the space button.

Select appropriate material for pre-stressing (as it is shown in the figure below).

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Figure 4-1: Load default properties importing material to the project database.

4.2 Definition of Tendon Groups

The tendon geometry will be simplified so that all the tendons positioned in the webs

will be grouped together and located in the middle of the cross-section. Due to that sim-

plification and the three construction stages only three tendons have to be defined.

Further simplification will be done based on the fact that the tendons overlap each other

on some intervals. For this reason only one tendon geometry (master tendon) has to be defined with the full 3D geometry over the whole length of the structure. Then the

individual tendon groups can be defined using the geometry of the master tendon. These tendon groups are called slave tendons.

This procedure will be used mainly for preliminary designs where the tendon geometry

has to be designed. The advantage is that you can change the geometry of all tendon

groups by changing only the master tendon.

Open the list for the definition of tendons under Structure Tendons Ele-ment Assignment.

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Select the insert after button to open the input window for master ten-don and tendon group definition.

Input the data as shown in the table below.

Definition of

Tendon Groups

Structure Type Type - internal Type - internal Type - internal Type - internal

Tendon

geometry Master profile Slave profile Slave profile Slave profile

Tendons Orginal

Geometry - 1 1 1

TndNum 1 101 102 103

Element Assign-

ment Material

AASHTO_LRF

D:_PTtendGr270

AASHTO_LRF

D:_PTtendGr270

AASHTO_LRF

D:_PTtendGr270

AASHTO_LRF

D:_PTtendGr270

Top Table Number 1 6 12 6

At [m2] 0.0016 0.0016 0.0016 0.0016

Ad [m2] 0.0050 0.0050 0.0050 0.0050

Beta

[Deg/m] 0.151 0.151 0.151 0.151

Friction 0.25 0.25 0.25 0.25

Descrip-

tion Master cable

Prestressing cable 101



Note: More detailed information about the individual entries in the input window can be found by call-

ing the program help (F1).

4.3 Assign the Tendon Group to the Elements

Now the elements have to be assigned to the tendons. This is how the program gets in-

formation about which elements the tendon passes through.

Select the insert after button in the lower table to open the input window

The tendon groups are listed in the upper table and the elements to be assigned to the

selected tendon are displayed in the lower table.

Input the data using the information shown in the table below.

Input the Cable As-

signment

STRUCTURE TdNum 1 101 102 103

El from 101 101 108 123

TENDON DATA El to 135 113 128 135

El step 1 1 1 1

EL. ASSIGNMENT

Bottom table

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4.4 Definition of the Cable Geometry

Now the actual geometry of the tendon will be defined. As already mentioned above, in

this example only the geometry of the master tendon will be defined. The salve tendons

will have the same geometry as the master tendon due to the definition above (slave

tendons with a reference to the master tendon).

Activate the master tendon in the upper list to start the definitions of the ten-don geometry.

Select the info button between the upper and lower list.

The input window for the graphical tendon geometry definition will be opened. Please

note that the graphical screen will be empty if you havent recalculated the cross-sections and the structure before. In this window the preview can be changed between

different views (CS view, elevation, plan, isometric and side elevation) that graphically

display the defined input.

Figure 4-2: Tendon geometry input window with graphical overview.

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Click the insert after button on the left bottom side of the screen to activate the

input field.

Define the tendon positions as it is shown in the table below.

The input for one tendon position is confirmed by clicking the APPLY button.

Input the Cable

Geometry

STRUCTURE TdNum 1

Ref. Elem. 101 104 108 111 114

TENDON DATA CS pnt - SP-B - SP-T -

X/L 0 0 0 0 0

GEOMETRY eY [m] 0 0.2 0 -0.4 0

eZ [m] 0 0 0 0 0

Bottom table Rel. to Elem CS pnt Elem CS pnt Elem

Alfa1 Free Value Free Value Free

Value - 0 - 0 -

Alfa2 Free Value Free Value Free

Value - 0 - 0 -

Rel. to Elem Node Elem Node Elem

Extern

TdNum 1

Ref. Elem. 118 123 126 133 135

CS pnt SP-B - SP-T SP-B -

X/L 0.5 0 0 0 1

eY [m] 0.2 0 -0.4 0.2 0

eZ [m] 0 0 0 0 0

Rel. to CS pnt Elem CS pnt CS pnt Elem

Alfa1 Value Free Value Value Free

Value 0 - 0 0 -

Alfa2 Value Free Value Value Free

Value 0 - 0 0 -

Rel. to Node Elem Node Node Elem

Extern

The tendon definition for the master tendon is now completed and will be displayed in the main graphic screen after calling redraw (freehand symbol V) or by rotating the system. The tendon profile is drawn in a turquoise color.

Note: More detailed information about the individual entries in the input window can be found by call-

ing the program help (F1).

The different ways of referring are shown more detailed in the figures below.

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CG

NODE

RP

Tendon position

CG

NODE

RP

Tendon position

CG

NODE

RP

Tendon position

ez

ey

ey

ez

ez

ey

Figure 4-3: Different references for the tendon position same tendon position but different eccentricities and different reference points.

Figure 4-4: Different references for the angle Alpha1 the same applies for Alpha2

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Note: The reference point has to be created in Modeler (or even in Analyzer) and the Reference-Set has

to be of type Geometry Point or Stress Check Point.

The reference point itself can also vary along the bridge axis. This method can be used to define

the tendon geometry sometimes it is the best approach. The tendon has to be created in the Ana-lyzer, and for the geometry definition the only thing that has to be defined is that the tendon is rel-

ative to the reference point (with or without any eccentricity) in all elements.

By finishing the tendon geometry definition of the master tendon, the geometry of the

slave tendons is also defined the reference to the master tendon was defined and the elements were also assigned already.

To see the all tendons in the general 3D view the project has to be calculated using the

same principle as before (recalculation of the cross-sections and structure check).

4.5 Definition of the Tendon Stressing Schedule

The tendon stressing actions are not defined in the stage directly but instead are defined

separately and are referenced later. The tendon stressing procedure is defined under

Tendon Actions. Select Schedule Stages Tendon Actions to start the stressing definitions.

All the actions that are applied to the tendons are defined in the two tables in this win-

dow. The top table lists all the actions applied to the tendons. The bottom table displays

details of the action for one tendon that is selected in the top table.

In this window all the actions (pre-stressing, wedge slip, relaxation, etc) for certain ten-

don (group) are defined.

The Tendon 101 is stressed in the first construction stage and can be stressed from both

sides. Tendons 102 and 103 are stressed in the subsequent construction stages stage 2 and stage 3. Due to practical capabilities of pre-stressing, these two tendons can be

stressed only from the right side.

Note: The left and right side of the tendon is defined by the tendon orientation x coor-dinates. The left side is there where the tendons starts and the right side is there where

the tendon ends or in another words XL < XR.

The stressing of the tendon can be defined by a force or by a factor, where the factor

refers to the maximum allowable stress in the tendon defined in the assigned material

(PropertiesMaterial).

Each tendon will be 5% overstressed initially, and then a wedge slip of 6 mm happens.

The result is that the stresses in the tendon are under the maximum allowable

stress/force.

Define the tendon stressing actions as is shown in the tables below.

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Input the Tendon Schedule

SCHEDULE. STRESS/RELAX/WEDGE PREL WEDL PRER WEDR

Type FACT. - FACT. -

STAGES TENDON 101 101 101 101

Factor / Wedge [m] 1.05 0.006 1.05 0.006

TENDON ACT: Stress label STG1 STG 1 STG 1 STG 1

Top table

STRESS/RELAX/WEDGE PRER WEDR PRER WEDR

Type FACT. - FACT. -

TENDON 102 102 103 103

Factor / Wedge [m] 1.05 0.006 1.05 0.006

Stress label STG2 STG2 STG3 STG3

The stress label has to be defined so that the tendon actions can be referenced by the

construction sequence definition.

By clicking the info button the stresses (and forces) in the tendon (selected by the action) up to the selected stressing action are graphically displayed.

Figure 4-5: Diagram of stresses and forces in the tendon after corresponding stressing action.

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5 Lesson 7: Load Management

Load Management (Schedule Load Definition Load Management) is used for automatic summation of permanent loads by grouping certain load cases. For example

the self weight from each construction stage is summed up to one load case (SW-SUM

= SW-STG1 + SW-STG2 + SW-STGn).

The main capability of the load management is:

An individual loading case can be defined so that, after calculation, its results are automatically added to 1, 2 or 3 other load cases.

An individual loading case can be defined so that, after calculation, its results are automatically combined into 1, 2 or 3 envelopes.

Loading cases and envelopes defined in Load Management could be set up (initialized;

created) using the LcInit function. Instead of using the LcInit function an automatic initialization of the Load Management load cases can be done by activating the check

box Init Load Manager in the Recalc pad.

Define the Load Management as it is shown in the table below.

Input for the Load Manager

Schedule Load Manag. SW SDL PT CS

Load case I SW-SUM SDL-SUM PT-SUM CS-SUM

Load Definition State Total Total Total Total

Load case II STG-SUM STG--SUM STG-SUM STG-SUM

Load Management State Total Total Total Total

Load case III - - - -

Top table State - - - -

Envelope I - - - -

Comb I - - - -

Envelope II - - - -

Comb II - - - -

Envelope III - - - -

Comb III - - - -

The load management can be also created by loading the appropriate load manager tem-

plate from Menu (Extras Loading and Stages Load Management Definitions (English). The Load Manager for traveler load (TR), wet concrete load (WC) incremen-

tal launching method (ILM) and for cable loads (CABLE) can be deleted or ignored.

The final creep loading case is CS-INF and should not be added to the general loading

case as it is necessary to have the final creep and shrinkage effects separate. This way

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the structure can be checked after construction (before final creep and shrinkage) with

live loading and other loading combinations and also at the time infinity with live load-

ing and other combination.

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6 Lesson 8: Load Definitions

Loads are defined by Load Cases or by Load Sets ( Schedule Load Definition Load Case Definition or Load Set Definition). Several loads can be combined into one Load Case or also in one Load Set.

Load Sets cannot be calculated directly in the construction stage actions which is why

they have to be assigned to a Load Case. One Load Set can be assigned to different

Load Cases. It is also possible to define a different multiplication factor for the loads

defined in the Load Set.

By creating a load case the defined load is not yet calculated. The load is calculated

with the calc action in the schedule actions.

In this example the loads will be defined only in the load cases.

6.1 Definition of Load Cases for Self Weight

The bridge is built in three construction stages so three separate self weight load cases

have to be created. Each of them has to be calculated in a separate stage.

Change into Schedule Load Definition Load Case Definition Top Table

The window is split into two lists. In the top list the load cases are listed, and in the bot-

tom list the defined loads for the selected load case are listed.

Define the self weight load cases as is shown in the table below.

Definition of Load Cases

Schedule Name SW-STG1 SW-STG2 SW-STG3

Type Permanent Permanent Permanent

Load

CaseDefinition Load Manag. SW SW SW

Description Self weight 1st

construction

stage

Self weight 2nd construction

stage

Self weight 3rd construction

stage

Top table

The type of the load case (Duration type: Permanent or Non-Permanent) defines if the

load is permanent or not i.e. will it be considered in the calculation of creep and shrinkage effects or not.

The input Load Manag. establishes the connection to the Load Manager. By choos-ing SW here, all the results due to the self weight loads (SW-STG1, SW-STG2 and SW-

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STG3) will be saved/copied (superposed) to two load cases defined in the load manager

SW-SUM and STG-SUM.

The load cases were created and now actual loads have to be defined.

Change into Schedule Load Definition Load Case Definition Bottom Table

The load type to be used in this example is Self weight just as load or Self weight load and mass

Definition of Load

Cases

Schedule. Number SW-STG1 SW-STG2 SW-STG3

Loading Uni-

form load

Uni-form load

Uni-form load

Uni-form load

Uni-form load

Load Case Defini-

tion Type

Self

weight

Self

weight

Self

weight

Self

weight

Self

weight

From 101 1201 114 1301 129

Bottom table To 113 1204 128 1304 135

Step 1 1 1 1 1

Rx 0 0 0 0 0

Ry -1 -1 -1 -1 -1

Rz 0 0 0 0 0

Gam

[kN/m3] 0 0 0 0 0

If gamma is set to 0 then the specific weight used in the calculation of the self weight is

taken from the one assigned to the element via the assigned material (see Structure Elements Material or Properties Material data). If the value is defined (and is not zero) then this values is taken as specific weight and used in the calculations.

In the load cases SW-STG1 and SW-STG2 the self weight of the piers also has to be

defined.

Note: For faster and easier definition of the load cases it would be possible to define first one load case

and the load for it. Afterwards, the subsequent load cases could be created by copying, renaming

and renumbering of the first load case.

Another approach would be: First create one load case (top table) and activate the option Load only elements, activated in current stage and then in the definition of the load (bottom table) de-fine/load all elements (stepwise: 101-135, 1201-1204 and 1301-1304; or at once: 101-1304) with

the same load type. Afterwards that load case has to be copied twice (the total number of the load

cases has to be the same as the number of the construction stages in our case this means three).

For detailed load description use program help (F1) or the Appendix where all load types are

explained.

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6.2 Definition of Load Cases for the Additional Loads

In this example three different superimposed dead loads (left concrete barrier, right con-

crete barrier and road weigh) will be created and calculated. All of them will be defined

in one load case.

These loads also have to be taken into account for the creep and shrinkage calculation

so they are set to permanent.

Insert Load Set

Schedule Name SDL

Type Permanent

Load Case Defini-

tion Load Manag. SDL

Top table

Define Load Sets for the Additional Loads

Schedule Number SDL SDL SDL

Loading Uniform load Uniform load Uniform load

Load Case Defini-

tion Type

Uniform con-

centric element load

Uniform eccen-

tric element load

Uniform eccen-

tric element load

From 101 101 101

Bottom table To 135 135 135

Step 1 1 1

Qx [kN/m] 0 0 0

Qy [kN/m] -35 -6.1 -6.1

Qz [kN/m] 0 0 0

Direction Global Global Global

Eccentricity - Local+Z Elem-Ecc

Local+Z Elem-Ecc

Ey [m] - 0 0

Ez [m] - +6.3 -6.3

Load applica-

tion Real length Real length Real length

Definition Load/Unit

length Load/Unit

length Load/Unit

length

During creation of the load cases the link to the load management was defined in the

same way it was for the self weight load cases (except that SDL was chosen).

The Z-Element eccentricity defines the eccentricity length (in the Z-direction - transver-

sal) between the element/cross-section gravity center and the node. This makes it pos-

sible to define the eccentricity relative to the node (same applies for the definition of the

horizontal load). In our case there will be no difference due to the cross-sections sym-

metry.

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Ez

CG

Figure 6-1: Local Y-Element eccentricity.

6.3 Definition of Load Cases for the Tendons

For now only the tendon geometry and tendon stressing procedure was defined. To ap-

ply the load on the structure load cases have to be defined. Define the load cases as it is

shown in the table below.

Insert Load Set

Schedule Name PT-STG1 PT-STG2 PT-SRG3

Type Permanent Permanent Permanent

Load Case Defini-

tion Load Manager. PT PT PT

Top table

Define Load Sets for the Tendons

Schedule Number PT-STG1 PT-STG2 PT-STG3

Loading Stressing Stressing Stressing

Load Case Defini-

tion Type

Tendon stress-ing

Tendon stress-ing

Tendon stress-ing

From 101 102 103

Bottom table To 101 102 103

Step 1 1 1

Type Increment

Force

Increment Force

Increment Force

The selection of the type of stressing (Incremental-Force or Total-Force) has effect only

if multi-stage stressing procedure is defined. It must be defined whether the total stress-

ing force of a stress level has to be applied or only the differential force when compared

to a previously applied stress group (for more information see the RM Analysis user

guide chapter 11.5.3).

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6.4 Definition of Load Cases for the Creep and Shrinkage Ef-fects

Insert Load Case

Schedule Number CS-STG1 CS-STG2 CS-STG3 CS-INF

Type Permanent Permanent Permanent Permanent

Load Case Defini-

tion Load Info CS CS CS -

Top table

Load cases for calculation of creep and shrinkage effects have to be created, but no load

definition (in the bottom table) has to be defined.

The definition of the load cases is done only for the load management and post-

processing the results of the calculation of the time effects (done by the creep action) are saved to these load cases and accordingly to the load cases defined in load manage-

ment.

The creep and shrinkage load cases are linked to the load management by the same

principle as other load cases definition of the load management label/input (CS). In this way the creep and shrinkage results are saved/copied to the CS-SUM load case and

added to the STG-SUM load case.

The final creep and shrinkage effect (at time infinite CS-INF) are saved only to that load case because there is no load management label defined for this load case. This has

to be done due to the combinations where different factors are used for time effects at

time 0 and time infinite.

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7 Lesson 9: Definition of Construction Stage 1

The required definitions (structure including tendons, load cases and tendon stressing

procedure) for the construction sequence calculation is finished and the definitions for

the construction sequence calculation can now start.

This definition is done under Schedule Stages Activation or Schedule Actions.

In the top table a construction stage is created (and listed) and some basic definitions are

defined. The bottom table changes between the Activations and Schedule Actions.

In the Activation table it is defined which elements are activated in the corresponding

(construction) stage the active elements becomes a part of active structural system and can be loaded and included in the calculation.

In the Schedule Actions table it is defined which actions (static calculations, dynamic

calculations, plot actions, design actions, list actions, etc.) should be performed in the

corresponding (construction) stage.

Construction stages have a start time and duration.

7.1 Creation of construction stages

Change to Schedule Stages Activation Top table

Select the append button to open the input window for the construction stage

definition. Insert the construction stage named STG1 and the description First construction stage here.

Use the same principle to add other stages (as is shown in the table below)

Input Active Elements

to Stage 1

Schedule Name STG1 STG2 STG3 STG-FIN

Description First con-struction

stage

Second construction

stage

Third construction

stage

Final con-struction

stage

Stages

Activation

Bottom table

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7.2 First construction stage

7.2.1 Activation

Change to Schedule Stages Activation Bottom table

Select the append button to open the input window for element activation

Activate the elements as is shown in the table below.

Input Active Elements for Stage 1

Schedule Activate

Deactivate

Stages From 101 1201 1100 1200

To 113 1204 1102 1200

Activation Step 1 1 1 1

Age 14 42 0 0

Bottom table ts 0 0 0 0

Age defines the age of concrete when it is activated for the first time (becomes a part of the structural system) and will be considered by the calculation of creep and shrink-

age effects. The input ts defines the time (after pouring the concrete) when shrinkage starts.

The spring elements also have to be activated they represent the support conditions.

7.2.2 Schedule actions calculations

Input the Calcu-

lation (Static) for Stage 1

Schedule Action

Calcu-lation

(Static)

Calcu-lation

(Static)

Calcu-lation

(Static)

Calcu-lation

(Static)

Calcu-lation

(Static)

Load case

action

Type Calc Stress Calc GROUT Creep LcInit

Stages

Inp1 SW-

STG1 - PT-STG1 - 1

STG-SUM

Inp2 - STG1 - STG1 - -

Inp3 - - - - -

Schedule Actions Out1 - - - - CS-STG1 STG1-

SUM

Out2 * * * - * -

Bottom table Delta-T 0 0 0 0 28 -

Calc is the actions which calculates a normal load case

Stress converts the tendon forces, defined through the definition of the tendon stressing

actions, into loads whereby the corresponding elements are loaded. However, these

loads are not calculated yet they are just converted.

The forces (pre-stressing effects) are calculated (applied on the structure) by the Calc

action which is the subsequent action, whereby a reference to the corresponding pre-

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stressing load case has to be defined Stress Label STG1 and the Load Case PT-STG1 reference the same tendon.

The Grout action simulates grouting of tendon ducts, and with this action the composite

behavior between the concrete elements (cross-section) and tendon is established (strain

in the tendon is equal to the strain of the corresponding elements).

Grouting also changes the cross section properties, which must be taken into account in

the calculation. This is done by the definition of the recalculation options defined in the

recalc pad (- duct areas, + tendon areas, - grouted areas). The new cross-sections values

are used in the global calculation and are also saved to the corresponding list file

(cross.lst).

With the Creep action the time effects are calculated creep and shrinkage of concrete and relaxation of tendons. The corresponding functions for the calculation are prede-

fined (and can be modified) under Properties Variables and are assigned to the ma-terials under Properties Material Data. The time effects can also be graphically dis-played under Results Plot Creep/Shrinkage Curves.

Delta-T defines how long a certain system is exposed to the time effects time to the next structural change or when an additional permanent load is added. The Number of

time steps (Input-1) defines in how many calculation intervals the whole time interval

(Delta-T) is subdivided, and it is possible that the subdivision step is linear or logarith-

mic (Recalculation pad C+S). For smaller time intervals it is recommended to use 1 time step, and for longer time intervals (for time infinite final creep) 3 to 5 (logarithmic) time steps. Each time step is saved to a separate load case and the total

effect is saved to the predefined dummy load case (Output-4).

For the calculation of relaxation (Include Steel relaxation in the recalculation options)

the summation load case has to be defined in the recalculation window (pad). This has

to be done to define which (permanent) loads have to be considered in the calculation.

With the Action LcInit (Load case Initialization) a certain load case can be copied or an

empty load case is created if there is no load case defined in the Input-1 an empty load case is created (initialized).

In this example the summation load case (STG-SUM) is copied to a new one (STG1-

SUM) at the end of the construction stage. At that time in the summation load case all

(calculated) loads from the first construction stage are summarized (SW-STG1+PT-

STG1+CS-STG1) due to the definitions in load management. To see the results of the

loads in the first construction stage only, this has to be done because subsequent stages

will add more loads to the STG-SUM load case.

The results of each calculation action can also be saved to a list file defined in each ac-

tion separately (definition of the Output-2).

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The second and third stage activations and stage actions are defined similar to the first.

Due to the similarity of the schedule actions the whole construction stage could be cop-

ied and the definition accordingly modified. The activations are not copied and have to

be defined according to the active system in the second construction stage.

Another way to define subsequent construction stages is to define (copy and modify)

them via TCL (here the data is exported, copied, modified and afterwards imported).

8.1 Element Activation

Input Active Elements

to Stage 2

Schedule Activate

Deactivate

Stages From 114 1300 1301

To 128 1300 1304

Activation Step 1 1 1

Age 14 0 42

Bottom table ts 0 0 0

8.2 Calculation (Static)

Input the Calculation (Static) for

Stage 2

Schedule Action Calculation

(Static)

Calculation (Static)



Type Calc Stress Calc GROUT

Stages Inp1 SW-STG2 - PT-STG2 STG2

Inp2 - STG2 - -

Inp3 - - -

Schedule Actions Out1 - - - -

Out2 * * * -

Bottom table Delta-T 0 0 0 0

Action Calculation

(Static)

Load case action

Type Creep LcInit

Inp1 - STG-SUM

Inp2 1 -

Inp3 -

Out1 CS-STG2 STG2-SUM

Out2 - -

Delta-T 28 -

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9.1 Element Activation

Input Active Elements to Stage 3

Schedule Activate

Deactivate

Stages From 129 1400

To 135 1402

Activation Step 1 1

Age 14 0

Bottom table ts 0 0


Input the Calculation

(Static) for Stage 2


(Static)




Type Calc Stress Calc GROUT

Stages Inp1 SW-STG3 - PT- STG3 STG3

Inp2 - STG3 - -

Inp3 - - -

Schedule Actions Out1 - - - -

Out2 * * * -

Bottom table Delta-T 0 0 0 0

Action Calculation

(Static)

Load case action

Type Creep LcInit

Inp1 - STG-SUM

Inp2 1 -

Inp3 -

Out1 CS- STG3 STG3-SUM

Out2 - -

Delta-T 21 -

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10 Lesson 12: Definition of Final Stage (Creep)

With the last construction stage the final state of the bridge will be simulated.

For this the super imposed dead loads will be applied on the structure and final time

effects will be calculated t= (Delta-T=10000 days).

No additional element activation is necessary because the entire system is already acti-

vated.


Input the Calcula-

tion (Static) for the Final Stage


(Static) Load case

action Load case

action Load case

action

Type Calc Creep LcInit LcAddLc

Stages Inp1 SDL - STG-SUM CS-INF

Inp2 - 5 - STG-INF-

SUM

Inp3 - - - -

Schedule Actions Out1 - CS-INF STG-INF-

SUM -

Out2 * * - -

Bottom table Delta-T - 10000 - -

In this stage the superimposed dead loads are applied first on the structure, and then the

final time effects are calculated.

In the end two final load cases are needed including all construction effects (loads) with and without final time effects. Two additional actions have to be defined for this.

After the calculation of the SDL loads the summation load case is updated (the SDL

results are added to the STG-SUM load case) due to the definition of the load manage-

ment. After the Creep action the summation load case (STG-SUM) is not updated with

the definition of the CS-INF load case the load case was not linked to load manage-ment. To create a summation load case including the long term creep and shrinkage

effects, the summation load case is copied (LcInit actions) and the final time effects

(CS-INF) are manually added (LcAddLc) to the copied load case (STG-INF-SUM).

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11 The Calculation

The construction stage definition is finished now and the first calculation can be done.

Click on the Recalc button .

Figure 11-1: Recalc pad.

11.1 Calculation options

Cross-section calculation

Cross-sections have to be calculated at least once. Hereby the file cross.lst is automati-

cally created. If the cross-section doesnt change (and was already calculated once) this step can be skipped.

Structure check

This calculation options checks the structure, deactivates all elements, initializes the

result database and creates a number of list files (material.lst, stress.lst, struct.lst and

tendon.lst)

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If the system doesnt change this option can also be, in certain circumstances, skipped in additional calculations (the calculation of the construction stages was done and all

stages are skipped; in this case also the option Init Load Manger has to be turned off).

Note that the envelope files (*.sup) are saved to the main directory (and not the

sub-directory DefaultSchedule) and are not automatically initialized (only by the

SupInit action in the schedule actions). The same follows for the list (*.lst), plot (*.pl

and *.pla) and influence (*infl) files which are created/overwritten by the calculation.

With the action GoDel (Group System commands) it is possible to delete the corre-

sponding files in the main working directory as same as in the sub directory. This is

recommended to do to ensure that no files from previous calculations remain.

Stage Calculation

Activation and calculation of the schedule actions in the constructions stages is done.

Influence-lines calculation

Influence lines have to be calculated at least once to make a live load calculation. If the

influence lines data exists (*.infl) and the structure or lane definition was not changed,

this options can be skipped for additional calculations.

Note: For now this option is not needed but can be activated.

Time Effects (C+S+Rel.)

To calculate the time effects this option has to be activated, even if creep actions in the

schedule actions are defined. This allows making fast calculations, without including

time effects, very easily.

Include Steel Relaxation

The relaxation of pre-stressing steel is also calculated with the calculation of creep and

shrinkage if this option is activated and the summation load case is defined.

Init Load Manager

Before starting with the calculation of the stages all load cases and envelopes defined in

load management are initialized (created).

11.2 Special settings

Cross-section correction

This option activates the calculation of the new cross-section values due to the tendons

in it as it explained in 7.2.2.

SumLC (summation load case)

This defines the summation load case of permanent loads which is used for several cal-

culations (Steel relaxation, camber calculation, etc).

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It is also used as an Initial Strain load case if the input of certain standard dependent

design checks (see Pre-Stressing Training Example Analyzer Part II) references it.

Calculation

By clicking the Recalc button (in the recalc pad) the recalculation of the active schedule

starts. By clicking on the Recalc all button, all schedule variants will be successively

calculated depending on the defined sequence.

Note: Schedule variants can be defined under Schedule Schedule Variants. Here it is possible to define different construction variants (construction schedules) on the same system and in the same

project (folder) where each variant is saved to its own subfolder.

The calculation status can be seen in the lower windows when the calculation is run-

ning. The status shows which stage, which action and which calculation steps are cur-

rently being calculated. If plot actions are also defined in the schedule, then the generat-

ed plots are displayed in the main window (4 at once).

A calculation protocol is created (recalc.log) and saved to the DefaultSchedule (if more

schedules are calculated the protocol is saved to the corresponding folder) as text file. Ii

is possible to open in from there or by clicking the corresponding button in the program

itself.

During the calculation warnings and errors can occur. The warnings are displayed at the

end of the calculation (e.g.: WARNING: System important files(s) cross.lst cannot be deleted!) and should be interpreted as hints which should be checked. On the other hand

the calculation is aborted automatically if the definition is incorrect (the calculation

cant proceed) ERROR (e.g.: in the schedule actions a load case wants to be calculat-ed but wasnt created; or the name of the created and calculated load case isnt the same; in this case the calculation is aborted and an error is displayed; ERROR: Load

case name of the LC does not exist.). The place that the calculation stopped can also be also seen in the schedule actions list those stages (top list) and actions (bottom list) which were calculated have an OK in the status column.

A running calculation can be aborted by hitting the ESC button.

The calculation starts (depending on the calculation options) with the calculation of the

cross-section values and structure control. Then the initialization of the load manger

(load cases) is done. Finally the construction sequence calculation starts, and the stages

are calculated in the order of their input. At the beginning of each stage the elements

are activated first, and then each stage action is calculated.

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12 Result presentation

In RM Bridge it is possible to represent the results in many different ways. Some of

them are explained in detail below.

12.1 Possibilities in presentation of results

One of the possibilities to see the results is via Results Load Cases / Envelopes (Influence lines, etc). Here certain result presentation options have to be defined: Load case / Envelope; Element Group (if created); Result component (Displacements,

Forces, Stresses); etc. Once this is defined it is possible to export the results to a list file (Print) or to make a diagram (Diagram). By clicking on the Diagram button a new

window opens where additional definitions have to done. Once this is finished the dia-

gram is created by clicking the OK button.

Another possibility (with the same approach as above) to create a diagram is by the def-

inition of so called RM-Sets. This approach will be explained in more detail in next

chapter.

The post processing can also be done with Plot Containers which are created under

Results Plot Conatiners and have to be plotted by the DoPlot action in schedule actions. Here not only results can be displayed but also the structure itself. This ap-

proach allows completely free design of the graphical output, but predefined Macros

facilitate rapid generation (for more information see the RM Analysis User Guide chap-

ter 8.4.2).

Many predefined plots (e.g.: tendon scheme, tendon geometry, cross-sections, material

diagrams, creep and shrinkage diagrams, load sets, etc) can be referenced directly in

schedule actions (List/Plot Actions) and plotted by recalculation of the project or only

by this actions (click Run action on the left side between the top and bottom list).

A comprehensive presentation (output) of structural data via cad files (DGN or DWG)

is possible within Draw Manager (Extras RM Draw Manager).

Reports can be created within TDF-Reports (File Reports (TDF) Create/Edit Structure).

An overview of schedule actions defined in each stage can be done by the HTML Stage

Viewer (Extras HTML Stage Viewer).

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12.2 Diagram creation via RM-Sets

Go to Properties RM-Sets Top table(list)

Click on the insert after button and define the name of an RM-Set. It is possible

to define the description also which will be seen in the created diagram. The

type of RM-Set is Result representation (RESULT).

Figure 12-1: New RM-Set.

After confirming the input by clicking on the OK button the window for the def-

inition of the diagram is opened by clicking on the i button.

Here you will see several tabs for the definition of the diagram. There are two tabs for

the general definitions (scale, paper size, paper orientation, etc) and three others for dif-

ferent result presentations:

Load Case results

Envelope results

Reinforcement

Normally the correct definition of a diagram (RM-Sets) has to include the definition of

the elements for which the results should be represented and what results should be rep-

resented. This includes:

definition of the load case / envelope / reinforcement

definition of the result component (bending moment, normal force, shear force, etc.) / leading superposition value (MinMz, MaxMz, MinQy,

MaxQ, MinNx, MaxNx, etc) and a result component / attribute set

If different result components are defined in one RM-Set the program will automatically

create more diagrams. The same follows also for the different types of reinforcement

(Attribute Sets)

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Change to the tab Elements.

Define the elements for which the results should be displayed as is shown in the

pictures below.

Figure 12-2: Definition of elements for which the diagram should be shown.

The approach shown above uses the predefined element groups which were created al-

ready in modeler (they could be also created/modified in Analyzer). The same could be

achieved in a different way as is shown in the picture below here the elements are selected by the definition of an element series.

1. Type of referencing to elements

2. Definition of elements

3. Confirming the input

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Figure 12-3: Definition of elements for which the diagram should be shown.

Change to the tab Load Cases.

Define the Load case for which the results should be displayed as is shown in

the picture below. This is similar to the way elements were chosen.

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It would be possible to add (Insert after) for the same result component different load

cases or for the same load case different result components. Of course, a mixture of both

is also possible. In this case more diagrams would be created.

If the stresses should be displayed, it has to be defined where in the cross-section the

stresses should be represented/calculated. This is done by the definition of additional

results parameters (dashed square) for stresses the stress point has to be chosen addi-tionally.

The diagram can be displayed by clicking on the Plot to file button. The same data can be exported also to list file (Report file) or to MS Excel (Write to XLS).

The definition of the RM-Set is confirmed by clicking on Save.

The created RM-Set/Diagram can also be seen under Results Plot RM-Sets.

1. Choosing of an Load Case

2. Definition of a result component

3. Confirming the input

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The diagram can be plotted in the schedule actions. This is done via the DgmSet action.

Using this action it is possible to plot many diagrams with one RM-Set. As it was al-

ready explained, the summation load case is updated after each calculation. Referring to

it within an RM-Set and plotting the RM-Set using the DgmSet action at different times

will produce different diagrams. But the name of the output file (plot file), defined in

the DgmSet action, has to be different (if not the diagrams are overwritten).

The plot files created using DgmSet are saved to the (DefaultSchedule). A fast access to

this directory is also possible under Results Plot Directory (DefaultSchedule).

1 General1.1 Starting the Program1.2 Subjects Covered in this Training

2 General Example Data2.1 Structural Model2.2 Cross-Section2.3 Substructure2.4 Pre-Stressed Tendon Layout for Internal Tendons

3 Lesson 6: Analyzer4 Lesson 6: Tendon Definitions4.1 Tendon Material Import4.2 Definition of Tendon Groups4.3 Assign the Tendon Group to the Elements4.4 Definition of the Cable Geometry4.5 Definition of the Tendon Stressing Schedule

5 Lesson 7: Load Management6 Lesson 8: Load Definitions6.1 Definition of Load Cases for Self Weight6.2 Definition of Load Cases for the Additional Loads6.3 Definition of Load Cases for the Tendons6.4 Definition of Load Cases for the Creep and Shrinkage Effects

7 Lesson 9: Definition of Construction Stage 17.1 Creation of construction stages7.2 First construction stage7.2.1 Activation7.2.2 Schedule actions calculations

8 Lesson 10: Definition of Construction Stage 28.1 Element Activation8.2 Calculation (Static)

9 Lesson 11: Definition of Construction Stage 39.1 Element Activation9.2 Calculation (Static)

10 Lesson 12: Definition of Final Stage (Creep)10.1 Calculation (Static)

11 The Calculation11.1 Calculation options11.2 Special settings

12 Result presentation12.1 Possibilities in presentation of results12.2 Diagram creation via RM-Sets

RM E Prestressing Basic Part1 AASHTO

Documents

definition of load cases

definition of tendon

load definitions

tendon definitions

load management

stressed tendon layout

tendon material import

types rm bridge v8i