Midas GSD Technical Material

Contents

GSD Overview

Step 1: Material Properties

Step 2: Section

Step 3: Rebars

Step 4: Load Combination

Step 5: Design Options

Step 6: Results

Data Exchange: AutoCAD, midas Gen

Design of Tapered Section

General Section Designer

Midas Information Technology Co., Ltd.http://en.midasuser.com

Program Version Gen 2011 (v1.1)

Release Date Oct 22, 2010

http://en.midasuser.com/


General Section Designer (GSD)Introduction to GSD

Step

00

It can be called from midas Gen by Tool > General Section Designer.

The following technical material contains complete description of GSD.

In Gen 2011 (v1.1), a new module General Section Designer or GSD has been added.

Scope of GSD

– Definition of any Irregular cross-section.

– Calculation of Section Properties.

– Generation of P-M, P-My-Mz, M-M interaction curves.

– Calculation of Section Capacity in flexure.

– Calculation of Safety Ratio based on the member forces.

– Generation of Moment-Curvature curve.

– Plot of Stress Contours for all the cross-section.

– All the above features are supported for

– RC Sections

– Steel Sections

– Composite Sections

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General Section Designer (GSD)User Interface

Step

00

Toolbar

Coordinates

Main Menu

Works Tree

Message Window

Unit Control

Table Window

Table Window

- In one model file, more than one sections can be created and saved under different section names.

- All the sections are tabulated in the Works Tree.

- Double click the section name in the Works Tree to show the section in the work-window and work on it.

Procedure

Works Window

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Rebar Area



General Section Designer (GSD)

Eurocode, UNI, British Standard, ASTM, Indian Standard,

etc.

• RC• Steel

Step

01

Applied Codes

Materials

Material

Nonlinear material properties can also be assigned to concrete and

structural steel and rebar materials.

Nonlinear Properties

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Step

01

Concrete Nonlinear Properties

Material: Nonlinear Properties

Parabola-rectangleParabolic stress-strain curve Kent & park model

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Step

01 Material: Nonlinear Properties

Asymmetric Bi-linearMenegotto -Pinto Tri-linear

Steel Nonlinear Properties

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Step

02 Section: Grid

Define Grid

Model > Define Grid…

or

Click in the Toolbar

- Point grid can be defined by the user.

- : Can be shown or kept hidden.

- : Snap to grid

- : Snap to object or shape

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Step

02 Section: Basic Shapes

Note: Shapes are the basic entities which combine to make a section

Shapes in GSD

- Basic Shapes:

- DB Shapes

- User-defined shapes

- General Shapes:

- Defined by mouse-click in work-window

- Defined by entering coordinates in a MS-

Excel compatible table.

Model > Shape > Basic Shape…

Material : Select the material from the drop-down

menu.

Insertion Point: Enter the coordinates on the

work-window where the centroid of the shape will be

placed.

Rotation/Beta Angle: By changing the Beta-

Angle, the orientation of the shape can be changed.

Hollow Shape: Check ON to create a hollow

shape.

Define Basic Shape

1

2

3

2

3

1

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4

4




Step

02 Section: General Shapes

Shapes in GSD

- Basic Shapes:

- DB Shapes

- User-defined shapes

- General Shapes:

- Defined by mouse-click in work-window

- Defined by entering coordinates in a MS-

Excel compatible table.

Model > Shape > General Shape…

Click in the green box and then at points P1,

P2, P3… in work-window to draw the shape. The

coordinates are automatically entered in the table.

Hole Type Shape (check off): Creates a solid

shape.

Hole Type Shape (check on): Creates a hollow

shape.

Define General Shape

1

2

3

2

3

1

Excel compatible

table

Solid Shape Hollow Shape

P1

P2

P3

1

2 3

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Step

02 Section: Translate Shape

Translate Shape

Move or copy the existing shape at equal or

unequal spacing.

Model > Shape > Translate…

Mode: Select Copy.

Click on SELECT button and select the shape to

be copied.

Enter the distance to new location.

Enter the Number of Times the Shape is to be

copied.

Copy Shape

24

2

3

1

Circular Shape copied two times to new location

2

1

3

4

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Step

02 Section: Merge Shapes

Merge Shapes

Merge two overlapping shapes into a single

shape.

-Only USER type or General type sections can be

merged

- Only the shapes having same material can be

merged.

Model > Shape > Merge Two Shapes…

or

Right-click in the work-window.

Click on SELECT button and select the shapes to

be merged.

Merge Two Shapes.

Merge Shapes

1

1

2

2

1

Merged Shapes

1

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Step

02 Section: Create Hollow Section

Hollow Section

Hole can be created in a USER type or General type

shape by creating a Hole type General Shape on it.

Create a Solid Shape.

Model > Shape > General Shape.

Enter the coordinates which define the perimeter

of the hole.

Check on “Hole Type Shape”.

Create Hole

2

1

2

3

4

Hollow Section

1

3

4

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Step

03 Rebar: Material

Model > Shape > General Shape.

- Rebar materials and Rebar sets can be defined

as per various international codes.

- Linear or Nonlinear stress-strain curve can be

assigned to the rebars.

Rebar Material

Menegotto-Pinto

1

Bilinear Model Park Strain Hardening 12/32




Step

03 Rebars: Placing the rebars (1)

Patterns

Various ways are available to assign the rebars

to a section. These ways are called Patterns in

GSD.

- Point Pattern

- Line Pattern

- Arc Pattern

- Rectangle Pattern

- Perimeter Pattern

Model > Rebar > Rebar-Point Pattern

Place a single rebar at a time either by entering the

coordinates into the table or by mouse-click on

the work-window.

Rebar data can also be directly copied to the table

from MS-Excel.

Point Pattern

Excel Compatible Table

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Step


Patterns



GSD.

- Point Pattern

- Line Pattern

- Arc Pattern

- Rectangle Pattern

- Perimeter Pattern

Model > Rebar > Rebar-Line Pattern

Place the rebars on a straight line drawn by the user

in the work-window.

Start Point / End Point : Enter the start point and

end point of the line.

No. of Interior Rebars: Enter the number of

rebars in the interior of the line.

Start Rebar / End Rebar: State whether the rebar

should be drawn at the start and end of the line.

Preview is shown in work-window before applying.

Line Pattern

Start Rebar

Interior Rebars1

2

2

3

3

1

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Step


Patterns



GSD.

- Point Pattern

- Line Pattern

- Arc Pattern

- Rectangle Pattern

- Perimeter Pattern

Model > Rebar > Rebar-Arc Pattern

Place the rebars on a circular arc drawn by the user

in the work-window.

Center of Arc: Enter the Center of the circle

Start Point/End Point: Enter the number of

rebars in the interior of the line.

Start Rebar / End Rebar: State whether the rebar

should be drawn at the start and end of the line.

Preview is shown in work-window before applying.

Arc Pattern

Start Rebar

Interior Rebars1

2

2

3

3

1

End Rebar

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Step


Patterns



GSD.

- Point Pattern

- Line Pattern

- Arc Pattern

- Rectangle Pattern

- Perimeter Pattern

Model > Rebar > Rebar-Rectngular Pattern

Place the rebars on a rectangle drawn by the user in

the work-window.

Corner 1/ Corner 2: Enter the coordinates of

corners of the rectangle.

Angle with Y axis: Enter the angle if the rectangle

is intended to be inclined to Y axis.

Rebar on 1 & 3 / Rebar on 2 & 4: Enter the

number of rebars on the sides.

Rotate Angle: Rotate the whole pattern by an

angle.

Rectangular Pattern

Three rebars on

sides 1 & 3

1

2

2

3

3

1

Two rebars on

sides 2 & 4

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4

Preview is shown before

applying




Step


Patterns



GSD.

- Point Pattern

- Line Pattern

- Arc Pattern

- Rectangle Pattern

- Perimeter Pattern

Model > Rebar > Rebar-Perimeter Pattern

Place the rebars around the outer perimeter with a

concrete cover defined by the user.

Distance between the concrete face and center

of rebar: Enter the concrete cover.

No. of Rebars: Enter the total number of rebras.

First of all, the rebars are placed at the corners

starting from left-top. Remaining rebars are

distributed to the side in proportion of their lengths.

Preview is shown in the work-window before applying.

Perimeter Pattern

1

2

2

1

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Step

03 Rebars: Change Rebar Pattern

Patterns

- One pattern of rebars denote a group of rebars.

Rebars of a pattern can‟t be treated individually. Any

modification in the rebar data in a pattern is applied

to all the rebars of that pattern.

- If we want to modify the data of a single rebar, at

first the pattern of the rebar should be changed to

Point Pattern.

Model > Rebar > Rebar-Perimeter Pattern

Place the rebars around the outer perimeter with a

concrete cover defined by the user.

Select to change all the pattern to Point Pattern.

Select to change a particular pattern to Point

Pattern.

After changing to Point Pattern, open the Rebar table

of Point Pattern from the Works-Tree by right click.

Any data in the rebar table can be edited.

Change Pattern

1

2

2

3

1

Rebar coordinates and diameter can be edited 18/32




Step

03 Rebars: Edit by dragging

Rebar of Point Pattern cane edited by dragging in the

work-window.

Click on SELECT button.

SNAP off.

Click on the rebar to be edited and move it to the

new position by dragging.

Edit by dragging

1

2

21

Rebar moved to a new position

3

3

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Step

04 Load Combination

Load Combination

Model > Define Load CombinationExcel compatible

table.

- Clockwise moment about the y and z axes are

taken as positive. Anti-clockwise moments are taken

as negative.

- P is taken as positive towards „+z‟ axis.

Sign Convention

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Step

05 Design Options

Partial Safety Factors

- Partial Safety Factors for concrete and steel can be

entered as per Eurocode 2:04 for the calculation of

the Section Capacity.

- User-defined Safety Factors can be used to find

the Section Capacity as per other design codes.

Options > Design Options

Gamma_c: Partial safety factor for Concrete.

Gamma_s: Partial safety factor for steel.

Alpha_cc: Coefficient taking account of long term

effects on compressive strength.

P-M interaction curve

1

2

3

2

1

3

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Step

06 Result: Section Properties

Section Properties

Following Section Properties are automatically

calculated:

I. General Properties:

– Area

– Shear Area (Asy, Asz)

– Moment of Inertia (Iyy, Izz)

– Torsional Constant (Ixx)

– Centroid (Cyp, Cym, Czp, Czm)

II. Section Modulus:

– Section Modulus –Top (Zyp)

– Section Modulus – Bottom (Zym)

– Section Modulus –Right (Zzp)

– Section Modulus –Left (Zzm)

III. Principal Properties:

– Principal Angle

– Moment of Inertia about principal axes

(Ipyy, Ipzz)

IV. Plastic Properties:

– Plastic Modulus-major axis (Syy)

– Plastic Modulus-minor axis (Szz)

3

y

z

CypCym

Czp

Czm

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Step

06 Result: Interaction Curve

Interaction Curve

- To generate the results: Check > Check Section

- We can see following interaction curves:

1. P-M interaction curve.

2. My-Mz interaction curve.

3. 3D interaction surface.

Result > Interaction Curve

P-M curve can be seen for all the angles from 0 to

360 by 15 degrees.


1

1

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Step


Interaction Curve







P-M curve can also be checked for all the load

combinations..

Checking Ratio for all the load combinations is

also shown.

- Checking Ratio can be calculated in three ways:

1.Keep M/P constant

2. Keep M constant

3. Keep P constant

Adds the current diagram to the Report generated

in Excel format.


1

3

1

2

3

2

4

4

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Step


Interaction Curve







P-M curve can also be checked for all the Load

Combinations..

Checking Ratio for all the load combinations is

also shown.

- Checking Ratio can be calculated in three ways:

1.Keep M/P constant

2. Keep M constant

3. Keep P constant


1

3

1

2

3

2

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Step


Interaction Curve







Click on “My-Mz” tab.

My-Mz curve is shown for the Axial force

specified by the user.

My-Mz curve can be seen for all the load

combinations.

Checking ration can be calculated in three ways:

1.Keep My/Mz constant

2. Keep My constant

3. Keep Mz constant

My-Mz interaction curve

1

4

2

2

3

3

1

4

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Step


Interaction Curve







Click on “3D” tab.

All the P-M curves can be seen at the same time.

P-M curve for the selected angle is shown in red.

All the M-M curves can be seen at the same time.

M-M curve for the selected Axial Load is shown in red.

The member forces along with the corresponding

capacity can be seen for the selected load

combination.

The Capacity Ratio is shown for all the load

combinations. The ratio > 1 is shown in red.

3-D interaction surface

1

3

2

2

3

4

1

4

5

5

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Step

06 Result: Moment-Curvature curve

Result > Moment –Curvature Curve

or

Click on “Moment-Curvature” tab.

Enter the Neutral Axis Angle.

Enter the Axial Load.

Enter the value of “Maximum Strain” upto which

the curve will be drawn.

Apply.

Move the mouse pointer on the curve to see strain

diagram for a particular point

Click Report to add the current diagram to the

report

Moment –Curvature curve

3

1

1

2

4

3

45

2

5

5

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6

6




Step

06 Result: Stress Contours

Result > Stress Contours

OR

Click on “Stress Contours” tab.

Select the Load Combination.

Check the maximum & minimum values.

Enter preferences for viewing stresses

Add to Report

Stress Contours

2

1

1

2

3

3

4

4

- Tension is taken as +ve and compression as –ve.

Sign Convention

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Step

06 Result: Report

Generating Report

-Report in MS-Excel format is generated on clicking

[Report] button in any of the result pages.

-It is saved in the same folder as that of the model file.

- Any item can be added to the report by clicking the

[Report] button.

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Step

-- Data Exchange: AutoCAD

Importing AutoCAD dxf files

Shapes created in AutoCAD can be imported into

GSD to create sections. Rebar coordinates can

also be imported as a separate layer.

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2

13

4

Model > Import AutoCAD DXF

Enter the dxf file to be imported.

Select layer of Shape.

Select layers for Rebars. More than one layers

can be selected for rebars.

Note: In AutoCAD, rebars must be represented by

circle.

Select material for the shape.

Specify diameter for rebars. Only one diameter can

be specified for all the rebars.

Specify the origin on GSD.

Import

1

2

3

4

5

6

3

4

5

6




Step

-- Data Exchange: midas Gen

Midas Link

GSD can be linked with midas Gen to

import/export the sections and the member

forces corresponding to the load combinations

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2

1

3

Link > midas Link

Select the Gen file to be linked with midas Gen.

The model files opened in midas Gen are shown in

Link dialog box.

Click CONNECT.

Switch to midas Gen and select the element

whose section and member forces are to be imported

in GSD.

Switch to GSD and click IMPORT.

Select the load combinations and the element part

for which member forces of the selected element will

be exported.

After adding rebars to the imported section, various

results like, interaction curves, M-C curve, stresses

can be generated.

Import

1

2

3

4

5

3

4

5

Gen: Load

Combination & part

GSD: midas Link

GSD: Section imported

Gen: Select element




Step

-- Design : Tapered Section (1)

Tapered Section Design

Sections of Tapered beams and columns along

with the member forces can be imported into

GSD from midas Gen. Section capacity and hence

the checking ratio can be calculated at a

specified location on the member.

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2

1

3

Link > midas Link

Set up the link with midas Gen model file

Switch to midas Gen and select the element

whose section and member forces are to be imported

in GSD.

Switch to GSD and click IMPORT.

Select the load combinations and the part of the

selected element in Gen, which should be exported to

GSD. If Part I and Part 2/4 are selected, the sections

at the two locations and also the member forces at

the two locations corresponding to the selected load

combinations will be exported to GSD.

Import

1

2

3

4

4

Gen: Select load combination & part

Midas Gen: Tapered beam

GSD: midas Link

GSD: Import




Step

-- Design : Tapered Section (2)

Tapered Section Design

The selected sections along with the member

forces are imported. Now rebars can be added to

the two sections (separately) and desired results

can be checked.

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3Link > midas Link

Two sections have been imported (shown in

works-tree.

Double click the first section to show it in the work-

window. Add rebars and see the results.

Similarly activate another section, add rebars and

see the results.

Add Rebars and Check results

1

2

3

3

4

Two sections importedChecking Ratio & Stress contours at the two

locations

1

2

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Documents

Midas GSD Technical Material