CSP00014[CIVIL-Tutorial]Composite Plate Girder Design-EC4

Bridging Your Innovations to RealitiesComposite Plate Girder DesignBridge Type

Program Version V7.8.0

Program License Registered

Revision Date Rev.1

- This Tutorial provides explanation of Design Procedure for Composite Steel Plate Girder Bridges in midas Civil.- The Design is done according to Eurocode 4: Design of composite steel and concrete structures- A composite bridge is the one which has a steel girder on which concrete slab is casted. Hence having two material

combined to act as one section.

Summary

Concrete

Steel

Composite Girder

Model View in midas Civil

Bridging Your Innovations to RealitiesEC 4 Design Procedure in midas

Input and output data

3

Design Code

Modeling and Analysis

- A pre-modeled structure is imported.

- Perform analysis

- Input Rebar data

Design Input Parameters

- Design Parameter

- Design Material

- Design Position

- Shear Connector

- Longitudinal Reinforcement & Stiffener

- Transverse Stiffener

- Transverse Stiffener of End Support

- Types of Load Application

- Lateral Torsional Buckling Data

- Damage Equivalence Factors

Design Result Tables

- Bending Resistance

- Resistance to Vertical Shear

- Resistance to Lateral-Torsional Buckling

- Resistance to Transverse Force

- Resistance to Longitudinal Shear

- Resistance to Fatigue

Bridging Your Innovations to RealitiesBridge Dimensions and General Section

Grillage Model , Skew

4

Drawings of the example structure

Figure 2. Layout of Grillage Model

Figure 1. Cross Section

Modeling

Bridging Your Innovations to RealitiesGeneral Features of the Bridge

Material , Section and Loads

5

Material

Inner Beam and Outer Beam :

Steel : S355

Concrete : C40/50

Section

Inner Beam and Outer Beam :

Composite Steel -I section.

Applied Loads

Self Weight of Steel

Surfacing Loads : 7.29 kN/m per girder.

Concrete Deck Slab weight : 17.23 kN/m per girder.

Vehicle Loads :

Applied Code : EN 1991 - :2003

Vehicle Load Type : Load Model 1, Fatigue Load Model 3

Bridging Your Innovations to RealitiesImporting Model File

Open the model file

Modeling

File>Open

Project>Model.mcb

1. Analysis>Perform Analysis

Bridging Your Innovations to Realities

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2

4

3

Material Properties

Check the Material data used in Design

Modeling

Model>Properties>Material

1. Select 3: SRC and click on Modify button.

2. Check the material properties of Steel.

3. Check the material properties of Concrete.

4. Click on Cancel button.

MIDAS Information Technology Co., Ltd.


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6

4

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Section Properties

Check the Section data used in Design

Modeling

25

1. Switch to Section tab.

2. Select Inner Beam and click on Modify button.

3. Check the sectional properties of Inner Beam.

4. Click on Cancel button.

5. In the same manner, check the sectional properties of Dummy and Outer

Beam.

6. Click on Close button.


Bridging Your Innovations to RealitiesSupport Conditions

Check table for Support Conditions

Modeling

In the works tree -

1. Right Click on Supports and

select Tables

Type 1

Translation in Z direction

restricted.

Node No. 1,2,4,5,27,36,38,39

Type 2

Translation in X and Z direction

restricted.

Node No. 3,37

Type 3

Translation in Y and Z direction

restricted.

Node No.

23,23,30,31,25,32,34,35

Type 4

Translation in X,Y,Z direction

restricted.

Node No. 29,33

Bridging Your Innovations to RealitiesDead Loads

Self Weight , Concrete Slab and Surfacing Loads

Modeling

In the works tree -

1. Right Click on Supports and select Display.

Element Beam loads can be seen in Graphic Model View with values.

Properties can be seen in Tables and can be edited here.


Bridging Your Innovations to RealitiesLive Loads

Moving Loads, Euro Code Load Model 1

Load> Moving Load Analysis Data >

Traffic Line Lanes.

1. The carriage way is divided in three lanes

of width 3m each, viz. Lane A,B,C.

Skew is specified and the load is dispersed

through the cross beam group.

Vehicles.

2. Load Model 1 has been applied.

Moving Load case.

3. A Moving Load case has been defined with

LM1 applied to the three lanes.

Modeling


Bridging Your Innovations to RealitiesConstruction Stages

Composite Construction

Modeling

Load> Construction Stage Analysis

Control>CS1 Modify/Show

1. Two construction Stages have been

defined. The cross Beams modeled as

Deck are activated after 10 days of

erecting Steel girder.

Load> Construction Stage Analysis

Control>Composite Section for

construction Stage.

2. We define the materials of composite

sections. The stage where composite

properties to be taken and age of the

concrete.

Bridging Your Innovations to RealitiesAnalysis and Load CombinationsAnalysis

Result > Combinations

1. Go to Steel Design Tab.

2. Click on Auto Generation

button.

3. Select Design Code as

Eurocode 0

4. Other input parameters as

Default.

5. Click OK.

6. Click Close.

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6

4

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2

5

Analysis > Perform Analysis

1. Analysis is performed and

results generated. Now we

enter post processing stage.



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3

2

4

5

Design Parameters

Set Global Design Parameters

Design

Design>Composite Plate Girder

Design>Design Parameters

1. Code: EN 1994-2

2. Enter the Partial Factors.

3. Damage equivalence factors (for

Resistance to fatigue): Design life

of the bridge in year (t Ld): 120

4. Ultimate Limit States: check

everything

5. Click on the OK button.

EN 1992-1-1

EN 1992-1-1

EN 1993-2: 6.1(1)

EN 1992-1-1

EN 1994-1-1: 2.4.1.2 (5)

EN 1992-1-1: 2.1.2.3 (1)

EN 1993-1-1

EN 1994-1-1: 2.4.1.2 (7)



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SRC Material

Define Material Properties for Plate Girder Design

Design


Design>Define Material

1. Select ID: 3

2. Steel Material Selection: Code: None,

Name: S355, Es: 205000 N/mm2,

Fu: 510 N/mm2, Fy: 355 N/mm2

3. Concrete Material Selection: Code:

None, Name: Grade40, Specified

Compressive Strength (fc/fck): 40

N/mm2

4. Reinforcement Selection: Code:

EN04(RC), Grade of Main Rebar:

Class A, Grade of Sub-Rebar: Class A




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2

5

3,6

7

4


Design>Longitudinal Reinforcement &

Stiffener

1. Select Inner Beam.

2. Enter the reinforcement data as shown in the

figure.

3. Click on Add/Replace button.

4. Select Outer Beam.

5. Enter the reinforcement data as shown

below.

6. Click on Add/Replace button.

7. Click on Longitudinal Stiffener Tab.

8. Enter the data as shown below in the figure

for inner and outer beams.


Data of Longitudinal Reinforcement

Reinforcement and Stiffener in the composite concrete

Design

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9


3

4

5

6

2

Check points

Define Design Positions.

Design


Design>Design Position

1. View>Select>Identity

2. Select Type: Section: 1: Inner Beam and 3:

Outer Beam

3. Click on Add button.

4. Check position: I&J





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3

4

Shear Connectors

Define Shear connector parameters for each girder.

Design

N=3


Design>Shear Connector

1. View>Select Previous

2. Enter data as shown in

figure. .



1

Sc= Longitudinal

Spacing of Studs



2

5

4

3

Transverse Stiffener

Enter the data for Transverse Stiffeners.

Design


Design>Transverse Stiffener

1. View>Select>Intersect Line

2. Select the elements as shown in

figure.

3. Enter the data as shown in.





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4

12

3

Transverse Stiffener (End Support)

Enter transverse stiffener of end supports.

Design>Composite Plate Girder Design>Transverse Stiffener

of End Support

1. Select Support: select 1, 5, 23, 25, 27, 31, 35 and 39.

2. Select Rigid end post.

3. ht: 0.08 m, t: 0.025 m, e: 0.474 m



e, Spacing of stiffeners

(Available for Rigid end

post only)

Design



Design>Types of Load

Application

1. View>Select>Intersect Line

2. Select the elements as shown in

figure .

3. Enter the data as shown in .



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5

4

3

3

Load Application

Define types of Load Application

Design

2

a : Spacing of Stiffener

Ss : Width of bearing at a loading point.

c : Distance from end to bearing in case of Type ( c ) .


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5

5

4

2

Lateral Torsional Buckling

Enter lateral torsional buckling data.


Design>Lateral Torsional Buckling

Data

1. View>Select>Identity

2. Select Type: Section: 1: Inner Beam

and 3: Outer Beam





Design

3

4

l : Distance between the springs ( default=0, boundary >0,) Cd : Spring stiffness (default=0, boundary >0)Alpha : Constant (default=2, boundary: 2~4,)a : spacing between the parallel beam (default=0, boundary >0,)




Design>Damage Equivalence Factors

1. View>Select Previous




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3

4

Damage of equivalence factors and Design

Define the damage equivalence factors and Perform Design

Design

2


Design>Design


- After design is performed, the DataForPlateGirder.txt file is automatically generated in the same

folder as model file. Detailed calculation process can be checked in the file.

Bridging Your Innovations to RealitiesClassification of Sections

To determine Resistance of structural steel cross section behavior needs to be determined

Classification is based on width to thickness ratios (C/t) of individual compression parts, material yield strength, and loading arrangement.

The steel section here is Class 1.

Classification

Design


1

Element 171Element 81

2

Bending Resistance

Checking Bending Resistance

Design>Composite Plate Girder Design>Design Result

Tables>Bending Resistance

1. Records Activation Dialog: Element: 81 and 171

2. Click on OK button.

Design

Sect. Class: Class of cross section

Ma,Ed: is the design bending moment applied to structural steel section before Composite behavior

Mc,Ed: is the part of the design bending moment acting on the composite section.

Bridging Your Innovations to RealitiesBending Resistance

Assumption and scope

The effective width of concrete flange is not calculated by the program. It needs to be consideredby the user when defining composite section.

The tensile strength of concrete is neglected.

Reinforcement in compression in a concrete slab is considered.

For Class 1 and Class 2 composite cross-sections, The bending resistance is verified by plastic resistance moment Mpl,Rd. For composite cross-sections with structural steel grade S420 or S460, where the distance xpl

between the plastic neutral axis and the extreme fiber of the concrete slab in compression

exceeds 15% of the overall depth h of the member, the design resistance moment MRd is

taken as Mpl,Rd where is the reduction factor. For values of xpl/h greater than 0.4 the non-linear resistance to bending MRd is applied and it

is determined as a function of the compressive force in the concrete Nc using the simplified

expression.

Design



Plastic resistance moment Mpl,Rd of a composite cross-section

Sagging

Hogging

For Class 1 and Class 2 members, Compression and tension forces are balanced and plastic neutral

axis is determined. The moment of resistance is thus found.

Design



For Structural steel grade S420 or S460,

Xpl / h > 0.15

MRd = Mpl,Rd

Xpl : Distance between the plastic neutral axis and the extreme fiber of the concrete slab in

compression

h : Overall depth of the member,

Design


Plastic resistance moment Mpl,Rd of a composite cross-section


Elastic resistance moment Mel,Rd of a composite cross-section

For Class 3 and Class 4 composite cross-sections, The bending resistance is verified by elastic resistance moment Mel,Rd. For cross-sections in Class 4, the effective structural steel section is calculated in

accordance with EN 1993-1-5, 4.3.

Design


k is the lowest factor such that a stress limit ( fcd, fyd, fsd) is reached .


2

3


Tables>Resistance to Vertical Shear

1. Activation Dialog: Element: 81 and 171


Vertical Shear

Check Resistance to Vertical Shear

Design


N_Ed:, Design value of the compressive normal force

M_Ed:, Design bending moment

V_Ed:, Design value of the shear force acting on the composite section

Bridging Your Innovations to RealitiesVertical Shear

Plastic Shear Resistance (V pl,Rd)

Av is

(Clause 6.2.6 (2) , EN 1993 -1-5)


The resistance to vertical shear Vpl,Rd is taken as the resistance of the structural steel section Vpl,a,Rd.and calculated as follows.


Shear Buckling Resistance

Contribution from the web

= 1.10 (Editable)

(Clause 5.2 (1) , EN 1993 -1-5)


The shear buckling resistance Vb,Rd of a steel web is calculated as follows.

The factor w for the contribution of the web to the shear buckling resistance is obtained from the table below.



- Transverse stiffeners at supports and

intermediate transverse or longitudinal

stiffeners or both:


Slenderness parameter

- Transverse stiffeners at supports only:

86.4

w

w

h

t

37.4

w

w

h

t k

-To calculate ki the expression given in Annex A.3 of EN 1993-1-5 is used with kst = 0.

- For webs with longitudinal stiffeners the slenderness parameter is not taken as less than

37.4

wi

w

i

h

t k



Contribution from flanges

-The effect of axial force is ignored when calculating Mf,Rd.

Verification


- When the flange resistance is not completely utilized in resisting the bending moment (MEd <

Mf,Rd) the contribution from the flanges is obtained as follows:

-VRd is taken as the minimum of plastic shear resistance and shear buckling resistance.


Interaction between shear force, bending moment and axial force.

: The design plastic moment of resistance of the section consisting of the effective area of

the flanges.

: The design plastic resistance of the cross section consisting of the effective area of

the flanges and the fully effective web irrespective of its section class.



2

3


Tables>Resistance to Vertical Shear



Lateral Torsional Buckling

Check Resistance to Lateral-Torsional buckling

N_Ed: Design value of the compressive normal force

M_Ed: Design bending moment

Nb,Rd: Design buckling resistance of the compression member.

Mb,Rd: Design buckling resistance moment.


Bridging Your Innovations to RealitiesLateral Torsional Buckling

Calculation of buckling resistance moment, Mb,Rd

:Reduction factor for lateral-torsional buckling

: Design Bending Moment resistance

: Imperfection factor, Value depends on h/b limits and buckling curve.

1.103 13

y we

LT

f

fL A

b Em A

(Clause 6.3.2.2 (1) , EN 1993 -2)

Awe, area is web compression zone

- Lateral torsional buckling of composite beams is verified using simplified method given in EN

1994-2, 6.4.3.2.

DESIGNERS GUIDE TOEN 1994-2, (D6.14)


(Clause 6.3.4.2 (7) , EN 1993 -2)Minimum of the two m values is used.

Where,

Segment of beam between rigid lateral supports with bending moment varying as a parabola


Calculation of buckling axial load, Ncrit

(Clause 6.3.4.2(6) , EN 1993 -2)



Design buckling resistance of compression member Nb,Rd

(Clause 6.3.1 (3) , EN 1993 -1-1)

is the reduction factor for the relevant buckling mode.

, ,

1Ed Ed

b Rd b Rd

N M

N M

Combined effects of axial forces and bending (Interaction Ratio)

Critical Bending Moment. (Mcr)



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3


Tables>Resistance to Transverse Force



Transverse Force

Check Resistance to Transverse Force

F_Ed:, Design transverse force

N_Ed:, Design value of the compressive normal force

My,Ed: Design bending moment applied to the composite section about the y-y axis

Mz,Ed: Design bending moment applied to the composite section about the z-z axis

F_Rd: Design resistance to local buckling under transverse forces

Bridging Your Innovations to RealitiesTransverse Force

Design Resistance to local buckling under Transverse forces.

Reduction factor due to local buckling ( Clause 6.4 (1) , EN 1993 -1-5)

Effective loaded length (Clause 6.3 , EN 1993 -1-5)

(Clause 6.2 (1) , EN 1993 -1-5)



Reduction factor is obtained by -

For Type a) with Longitudinal stiffener

(Clause 6.4(2) , EN 1993 -1-5)

(Clause 6.2 (1) , EN 1993 -1-5)

(Figure 6.1 , EN 1993 -1-5)



Where,

b1 is the depth of the loaded subpanel taken as the clear distance between the loaded flange and the stiffener

I sl,1 is the second moment of area of the stiffener closest to the loaded flange including contributing parts of the web

Conditions -

Calculation of ly, effective loaded length

(Clause 6.5 , EN 1993 -1-5)



For type (a) and (b)

For type (c)

Minimum of these two values.



Verification

(Clause 6.6(1) , EN 1993 -1-5)

(Clause 4.6(1) , EN 1993 -1-5)

Interaction between transverse force, bending moment and axial force


2

3


Tables>Resistance to Longitudinal Shear



Longitudinal Shear

Check resistance to longitudinal shear

V_L,Ed: Longitudinal shear force acting on length of the inelastic region

v_L,Ed: Design longitudinal shear force per unit length at the interface between


Bridging Your Innovations to RealitiesLongitudinal Shear

Design shear resistance of a single connector PRd

(Clause 6.6.3.1(1) , EN 1994 -2)

whichever is smaller, with

Bridging Your Innovations to RealitiesShear Resistance

Design longitudinal shear force per unit length at the interface between Steel and concrete

,

Ed

L Ed

V Azv

I

, /(2 )Ed L Ed cv v t tc, Slab thickness

, ( of ) /L Rd Rdv P number Stud Pitch


A is the effective transformed area on the side of the plane concerned that does not

include the centroid of section.

is the distance in the plane of bending from the member neutral axis to the centroid

of area A.

I is the second moment of area of the effective cross-section of the member.

z

DESIGNERS GUIDE TO EN 1994-2 p.118

Bridging Your Innovations to RealitiesShear Resistance

Design longitudinal shear force

, , ,

, ,

, ,

( )( )

( )

c f c el Ed el Rd

L Ed c c el

pl Rd el Rd

N N M MV N N

M M

The calculation is valid for positive My. For negative moment, it is 0 :



1

2

lamda_v: Damage equivalent factors

delta Tau: Range of shear stress for fatigue loading

delta Tau: Equivalent constant amplitude range of shear stress related to 2 million cycles

Fatigue Resistance

Check Resistance to Fatigue


Tables>Resistance to Fatigue




Bridging Your Innovations to RealitiesFatigue Resistance

Assumption and scope

Headed stud is checked for fatigue verification. The fatigue assessment for reinforcement, concreteand structural steel is not supported.

Fatigue assessment is carried out based on damage equivalence factor, v.

Fatigue Load Model 3 of EN 1991-2: 2003, 4.6 needs to be applied for verification of fatigueresistance.

The longitudinal shear per unit length for stud shear connectors is calculated by the program.

Design



Equivalent constant range of shear stress

The equivalent constant range of shear stress E,2 for 2 million cycles is calculated by the program.

Design


,2E V

,

2

( ) /

/ 4

L Edv Pitch n

d

,

Ed

L Ed

V Azv

I

Pitch = Spacing of Studs

n = Number of Studs


Damage equivalent factor

,1 1.55V ,2V

1/ 8

,3100

Ld

V

t

,

Ldt = Design life of the bridge in years. Default value is 120. Editable.


The damage equivalent factor v for headed studs in shear is calculated from

,1 ,2 ,3 ,4V V V V V

,4V need to be entered by the user.and


Verification

,2

,

1.0/

Ff E

c Mf s


The fatigue assessment for stud connectors is made by checking the following criterion on theassumption that stud connectors are welded to a steel flange that is always in compression under the

combination of actions:

- The default values for Ff and Mf,s are 1.0 and 1.0, respectively. They are editable.c is the reference value of fatigue strength at 2 million cycles with c equal to 90 N/mm

2.

The interaction between shear stress range E in the weld of stud connectors and the normal stressrange E in the steel flange is not verified in the program.

Documents

CSP00014[CIVIL-Tutorial]Composite Plate Girder Design-EC4