Function
- Enter the sectional properties for the following structural elements: Truss, Tension-only, Compression-only, Cable, Gap, Hook, and Beam Element.
- In the Composite tab, you input the properties of the composite pre- and post-sections required for the analysis of a composite bridge considering the variation of cross-sections before and after construction.
- In this dialog box, the sectional data pertaining to the "Analysis considering the section variation before and after composite actions in Composite Bridges" are specified.
Call
From main menu, select [Properties] tab > [Section Properties] group > [Section Properties] > [Composite]
Input
Section(Composite) dialog_Box Type
Section Type
Assign a section type of girder.
|
Steel-Box |
Steel-I |
Steel-Tub |
Composite-I |
Composite-T |
Steel-Box (Type 1) : Structural steel Box Shape Girder.
Steel -I (Type 1) : Structural Steel I Shape Girder.
Steel -I (Type 2) : Structural Steel I Shape Girder. Asymmetric section can be defined.
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Steel -Tub (Type 1) : Structural Steel Tub Shape Girder.
Steel -Tub (Type 2) : Structural Steel Tub Shape Girder. Asymmetric section can be defined.
Composite-I : Prestressed concrete I Shape Girder.
Composite-T : Prestressed concrete T Shape Girder.
Composite-PSC : Prestressed Concrete Girder defined as PSC-Value type in the PSC tab.
Composite-General : Section properties defined as materials, parts in SPC (Sectional Property Calculator).
User : Section properties defined as General Section in the Value tab.
Slab
Enter the dimensions for slab.
Bc : Effective slab width for one girder
tc : Thickness of slab
Hh : Distance from the top of girder to the underside of slab (The height of haunch)
Girder
Hw : Height of web excluding flanges
tw : Thickness of web
B1 : Width of top flange (distance between web centers in Box type)
B2 : Width of bottom flange (distance between web centers in Box type)
Bf1 : Top flange overhang from the center of web in Box type
Bf2 : Bottom flange overhang from the center of web in Box type
tf1 : Thickness of top flange
tf2 : Thickness of bottom flange
Click Stiffener... to define the longitudinal stiffener for Steel Box / Steel I / Steel Tub section.
Flat Stiffener Tee Stiffener U-Rib Stiffener
Stiffener : Enter the dimensions of the stiffener as per the image shown above.
Add : Add a new longitudinal stiffener.
Modify : Modify an existing longitudinal stiffener.
Delete : Delete the selected longitudinal stiffener from the list.
Stiffener Position : Chose the stiffener to be positioned on the left or right or both sides of the web of Steel-I girder.
N Left : Number of stiffener on the left web (tub and box girder) or the left of web (I girder).
N Right : Number of stiffener on the right web (tub and box girder) or the right of web (I girder).
N Bottom : Number of stiffener on the bottom flange.
N Top : Number of stiffener on the top flange.
C : Check the box to consider the longitudinal stiffener for the section property calculations. If the box is unchecked then the stiffeners are considered only for design and not for the section property calculations.
Hw : Height of web excluding flanges
tw : Thickness of web
B1 : Width of top flange
B2 : Width of bottom flange
tf1 : Thickness of top flange
tf2 : Thickness of bottom flange
Click Stiffener... to define the longitudinal stiffener for Steel Box / Steel I / Steel Tub section.
Flat Stiffener Tee Stiffener U-Rib Stiffener
Stiffener : Enter the dimensions of the stiffener as per the image shown above.
Add : Add a new longitudinal stiffener.
Modify : Modify an existing longitudinal stiffener.
Delete : Delete the selected longitudinal stiffener from the list.
Stiffener Position : Chose the stiffener to be positioned on the left or right or both sides of the web of Steel-I girder.
N Left : Number of stiffener on the left web (tub and box girder) or the left of web (I girder).
N Right : Number of stiffener on the right web (tub and box girder) or the right of web (I girder).
N Bottom : Number of stiffener on the bottom flange.
N Top : Number of stiffener on the top flange.
C : Check the box to consider the longitudinal stiffener for the section property calculations. If the box is unchecked then the stiffeners are considered only for design and not for the section property calculations.
Symmetric Section Auto Calculation : Check on the option to generate symmetrical section in the element’s local z-axis.
Distance from Reference Line : Specify the value to define asymmetrical section as shown in the figures below. This field will be inactivated when “Symmetric Section Auto Calculation” option is toggled on.
Asymmetrical Slab
Sg : Distance from the left side of the slab to the reference line
Top : Distance from the left side of the top flange to the reference line
Bottom : Distance from the left side of the bottom flange to the reference line
Girder
B1 : Top flange left overhang from the center of web
B2 : Top flange right overhang from the center of web
B3 : Bottom flange left overhang from the center of web
B4 : Bottom flange right overhang from the center of web
H : Height of web excluding flanges
t1 : Thickness of top flange
t2 : Thickness of bottom flange
tw : Thickness of web
Stiffener
Stiffener : define the longitudinal stiffener for Steel Box / Steel I section.
Define Stiffeners : Enter the dimensions of the stiffener as per the image shown below.
Flat Stiffener Tee Stiffener U-Rib Stiffener
Deck & Stiffeners : Enter the position of stiffeners.
Deck Position : Select the position where the stiffener will be positioned among the left/right of the web and top/bottom flange.
Deck Part : Select the flange part where the stiffener will be positioned among flange left/right overhang and flange between web centers
Ref. Point Position : Reference position to determine stiffener position
Left Ref. Point Position Right Ref. Point Position
Stiffener Numbe r: Number of stiffener on the specified deck position and part
C : Check on the option to consider the longitudinal stiffener for the section property calculations. If the box is unchecked, the stiffeners are considered only for design and not for the section property calculation.
Spacing : Distance from the reference point position to enter the stiffener
Stiffener : Select the defined stiffener type from the combo-box. Stiffener can be defined by clicking [Define Stiffener…] button above.
Stiffener Pos. : Stiffener position. Following positions can be selected by Deck Position: For Top Flange, select “Bottom”. For Bottom Flange, select “Top”. For Web, select “Left”, “Right” or “Both”.
Stiffener Names: Enter the stiffener name to be entered in the list.
Add : Add a new longitudinal stiffener.
Modify : Modify an existing longitudinal stiffener.
Delete : Delete the selected longitudinal stiffener from the list.
Limitation
1. Steel Composite Girder Wizard does not support Steel-I (Type 2) section.
2. Design of steel composite girder defined with Steel-I (Type 2) section is provided only for SNiP/SP design code. As for the Steel-I (Type 1) section, the design to SNiP/SP design code is not supported.
3. Auto-definition of temperature gradient of steel composite girder to the SNiP/SP design code is provided for both Steel-I (Type 1) and Steel-I (Type 2) section.
Hw : Height of web excluding flanges
tw : Thickness of web
B1 : Clear spacing between the top flanges in Tub type
B2 : Width of bottom flange (distance between web centers in Tub type)
Bf1 : Top flange width
Bf2 : Bottom flange overhang from the center of web in Tub type
tf1 : Thickness of top flange
tf2 : Thickness of bottom flange
Bf3 : Top flange overhang from the center of web in Tub type
tfp : Thickness of fictitious top plate
Steel tub sections have very low inherent torsional resistance. Hence, practically the top flanges of a steel tub are always connected via a bracing to increase this torsional resistance. Ignoring this torsional resistance can lead to erroneous results in pre-composite stage, especially in cases where torsional rigidity plays important role. Example of such cases would be bridges with skew and curvature, wherein the bearing reactions would be greatly altered. General practice in such cases is to idealize this tub section as a box section, wherein the thickness of the top flange is calculated manually depending on the type and spacing of the bracings.
Click Stiffener... to define the longitudinal stiffener for Steel Box / Steel I / Steel Tub section.
Flat Stiffener Tee Stiffener U-Rib Stiffener
Stiffener: Enter the dimensions of the stiffener as per the image shown above.
Add : Add a new longitudinal stiffener.
Modify : Modify an existing longitudinal stiffener.
Delete : Delete the selected longitudinal stiffener from the list.
Stiffener Position : Chose the stiffener to be positioned on the left or right or both sides of the web of Steel-I girder.
N Left : Number of stiffener on the left web (tub and box girder) or the left of web (I girder).
N Right : Number of stiffener on the right web (tub and box girder) or the right of web (I girder).
N Bottom : Number of stiffener on the bottom flange.
N Top : Number of stiffener on the top flange.
C : Check the box to consider the longitudinal stiffener for the section property calculations. If the box is unchecked then the stiffeners are considered only for design and not for the section property calculations.
Symmetric Section Auto Calculation : Check on the option to generate symmetrical section in the element’s local z-axis.
Distance from Reference Line : Specify the value to define asymmetrical section as shown in the figures below. This field will be inactivated when “Symmetric Section Auto Calculation” option is toggled on.
Asymmetrical Slab
Sg : Distance from the left side of the slab to the reference line
Top : Distance from the left side of the top flange to the reference line
Bottom : Distance from the left side of the bottom flange to the reference line
Girder
B1 : Top left flange width
B2 : Clear spacing between the top flanges in Tub type
B3 : Top right flange width
B4 : Bottom flange left overhang from the center of web in Tub type
B5 : Width of bottom flange (distance between web centers in Tub type)
B6 : Bottom flange right overhang from the center of web in Tub type
H : Height of web excluding flanges
t1 : Thickness of top flange
t2 : Thickness of bottom flange
tw1 : Thickness of left web
tw2 : Thickness of right web
bf1 : Top left flange overhang from the center of web in Tub type
bf2 : Top right flange overhang from the center of web in Tub type
tfp : Thickness of fictitious top plate.
Steel tub sections have very low inherent torsional resistance. Hence, practically the top flanges of a steel tub are always connected via a bracing to increase this torsional resistance. Ignoring this torsional resistance can lead to erroneous results in pre-composite stage, especially in cases where torsional rigidity plays important role. Example of such cases would be bridges with skew and curvature, wherein the bearing reactions would be greatly altered. General practice in such cases is to idealize this tub section as a box section, wherein the thickness of the top flange is calculated manually depending on the type and spacing of the bracings.
Stiffener
Stiffener : define the longitudinal stiffener for Steel Box / Steel Tub section.
Define Stiffeners : Enter the dimensions of the stiffener as per the image shown below.
Flat Stiffener Tee Stiffener U-Rib Stiffener
Deck & Stiffeners : Enter the position of stiffeners.
Deck Position : Select the position where the stiffener will be positioned among the left/right of the web and top/bottom flange.
Deck Part : Select the flange part where the stiffener will be positioned among flange left/right overhang and flange between web centers
Ref. Point Position : Reference position to determine stiffener position
Top Ref. Point Position Bottom Ref. Point Position
Left Ref. Point Position Right Ref. Point Position
Stiffener Number : Number of stiffener on the specified deck position and part
C : Check on the option to consider the longitudinal stiffener for the section property calculations. If the box is unchecked, the stiffeners are considered only for design and not for the section property calculation.
Spacing : Distance from the reference point position to enter the stiffener
Stiffener : Select the defined stiffener type from the combo-box. Stiffener can be defined by clicking [Define Stiffener…] button above.
Stiffener Pos. : Stiffener position. Following positions can be selected by Deck Position: For Top Flange, select “Bottom”. For Bottom Flange, select “Top”. For Web, select “Left”, “Right” or “Both”.
Stiffener Names: Enter the stiffener name to be entered in the list.
Add : Add a new longitudinal stiffener.
Modify : Modify an existing longitudinal stiffener.
Delete : Delete the selected longitudinal stiffener from the list.
Joint on/off : Check on the Joints in the guide diagram to activate the entry fields to additionally define the variant dimensions of the section.
J1, JL1, JL2, JL3, JL4, JR1, JR2, JR3, JR4
Size-I Import... : Import a section defined by PSC Section.
HL1, HL2, HL3,.. : Enter the section dimensions referring to the guide diagram.
PSC Viewer : PSC Viewer illustrates the section dimension guide diagram to true scale.
Joint on/off : Check on the Joints in the guide diagram to activate the entry fields to additionally define the variant dimensions of the section.
J1, JL1, JL2, JL3, JL4, JR1, JR2, JR3, JR4
Size-I Import... : Import a section defined by PSC Section.
HL1, HL2, HL3,.. : Enter the section dimensions referring to the guide diagram.
PSC Viewer : PSC Viewer illustrates the section dimension guide diagram to true scale.
PSC Vaule Type : Click Import... to import a PSC section from the PSC Section tab.
Web thickness for shear(total) : Web thickness value used for shear resistance design calculation in composite general section.
Before(After) Composite
If "User" is selected in Section Type, select Before & After Composite sections.
Section
Select the section data to be applied s Before/After Composite sections from the section data already defined under other tabs such as DB/User, Value, ect.
Material
Click Select Material from DB... to select the material properties for steel and concrete stored in the DB for a country. The following items are automatically entered.
One material data can be assigned to an element. Composite section consists of two parts, i.e. beam and slab which have two different materials. Thus, assign composite section the material data corresponding to beam and then define material data for the slab from the composite section in terms of ratio of material properties of beam to slab.
Es/Ec : Modulus Ratio, steel to concrete
Ds/Dc : Density ratio, steel to concrete
For the calculation of section properties of Composite Section, concrete is converted into steel. The self-weight is computed as follows:
The Weight of Composite Section = Steel Weight + Concrete Weight
If Ds/Dc = 0, concrete weight is ignored and only steel weight is considered.
Ps : Poisson's ratio of steel
Pc : Poisson's ratio of concrete
Ts/Tc (or Tgd/Tsb) : Ratio of thermal expansion coefficient of steel and concrete (or Ratio of thermal expansion coefficient of girder and slab)
These ratios will be used when the composite section is used without construction stages where the material data of Composite Section for C.S. will be used with priority.
Select Material from DB... : The properties of the concrete and steel to be used will be automatically entered by selecting data from the database.
In the stiffness calculation of composite sections, the concrete is considered as steel by substitution. The self-weight based on the material is estimated as follows.
Selfweight of Composite = Selfweight of Steel + Selfweight of RC
When Ds/Dc is entered as 0, the self-weight of RC is ignored, and only the self-weight of steel is considered.
Multiple Modulus of Elasticity
According to the design criteria 3.9.2.6 and 3.9.2.8 for highway bridges, the calculation of stresses due to creep and drying shrinkage of the concrete slab requires the reassessment of the elastic modulus. Therefore, multiple applications of elastic modulus ratios are necessary for the same cross-section under different load conditions. EN1994-2 (Eurocode 4: Design of composite steel and concrete structures, Part 2) 5.4.2.2 specifies the application of this provision for analysis and stress checks.
By checking the "Check" option and inputting the ratios Es/Ec (Long Term) and Es/Ec (shrinkage), the composite section properties considering these factors will be calculated.
For the calculation of the post-composite section moment of inertia (Ixx), the shear modulus ratio (Gs/Gc) is used instead of the elastic modulus ratio (Es/Ec). When selecting the material data from the database for inputting the elastic modulus ratio (Es/Ec), the Poisson's ratio from the material database is used to calculate Gs and Gc. If the user directly inputs the elastic modulus ratio (Es/Ec), the Poisson's ratio is treated as 0.