Composite Section for Construction Stage

 

 

Define an analytical model for each construction stage by assigning activated or inactivated sections corresponding to each construction stage of a composite bridge.

[Checking member forces & stresses for each part of a composite section]

 

 

 

From the Main Menu select Load > Construction Stage > Construction Stage Analysis Data > Composite Section for C.S.

 

 

 


Add a new composite section to be used for Construction Stage analysis to the section list. The new composite section is added to the end of the list.


Modify or check the data for the composite section selected in the list.


Delete the composite section selected in the list.

 
Recalculate Notational Size of Member, h, using the input section data.

 

When a new composite section is defined

In order to define a stage at which a Composite Section is added, click to prompt "Add/Modify Composite Section for Construction Stage" and enter the following:

Active Stage: Specify the construction stage at which the composite section defined becomes activated. Generally, this is the step activating each section before the composite action occurs.

Section: Specify the Section from the list.

Composite Type: Specify a Composite Section Type.

Normal: When a composite section or PSC section is used.

User: When the User is specifying an arbitrary section.

Section Type: Check the Section Type specified.

Section Shape: Check the Section Shape specified.

Element List: Check the Element Numbers for which the composite section is specified.

Note

The centroid of the section is adopted in different manner for General/Normal and User type.[Details]

Construction Sequence

Part: Location of each portion of a composite section

Mat. Type

Element: Select by element. In this case, the material properties that are already defined for the element are used.

Material: Select by material. In this case, the material properties selected are used for the analysis, whereas the material properties already defined are not used.

Note
SRC material can be used for Composite Section. When a Composite Section with SRC material applied is selected and Element is selected as the Material Type, Steel properties of SRC material will be used.

Material: Select Material. If 'Material' is selected from 'Mat. Type'. the user can define the material property in this section.

Compo. Stage: Select the Construction Stage in which the composite section becomes activated. Since part no.1 is a part before the composite action for the section occurs, Part No.1 needs to be selected as the Active Stage.

Age: Specify the age when the composite section becomes activated. The age inputted during the general construction stage will be ignored, whereas the age inputted here will be activated and used during analysis.

h : Enter the Notional Size of Member for each Part. h=2*Ac/u (Ac : Section Area, u : Perimeter in contact with atmosphere)

  • Limitation for the value of 'h'  

The value of h must be greater than zero. If h is zero, analysis will be not proceed except for the following conditions:

1. When elements to which selected sections are assigned in Section does not exist at Active Stage

2. When section types are Steel-I or Steel-Box, specified as Part 1.  

3. When Material Type is specified as Material, and Material is specified as Steel.

4. When Material Type is specified as Element, and all the elements defined in the Element List are steel.

  • Data processing when opening a model file generated in an older version

When Material Type is specified as Element, enter zero for 'h' except for the following conditions.

1. When the values of h in the Change Element Dependent Material Property dialog have been entered identically for all the elements specified in the Element List.

2. When identical Time Dependent Material properties have been assigned to all the elements specified in the Element List.

 

When Material Type is specified as Material,

1. Materials properties selected in Material and the h values of the linked time dependent properties are used.

2. When material properties selected in Material and Volume Surface Ratio in the linked time dependent properties are used, ‘h’ will be assigned zero

 

Note

1. In case of Composite & PSC section types, "h" is automatically calculated and the user may revise the values.

2. When calculating total perimeter "u", the influence coefficient for the enclosed part is not considered.

 

v/s : Enter the volumn-surface ratio for each part. It is applied when Time Dependent Material(Creep/Shrinkage) is defined according to ACI, PCA and combined(ACI &PCA).

Scale: This defines the scale. Input the scale for section properties of each part.

Stiff.: Specify the section Stiffness of each part.

Note
Section properties entered in Section are not applied to Composite Section for Construction Stage, but are used to only show the shape. Rather section properties input in Composite Section for Construction Stage will be used. This is because time-variant modulus of elasticity must be reflected in Composite Section for Construction Stage.

Stiff.Scale: Specify Scale Factor for section properties

Note
Torsional stiffness and effective shear areas are calculated by summing the values of each part, which are different from the actual section properties of the post-composite section. Stiffness Scale Factor allows us to adjust the section properties for the post-composite section.

Compo.Stiff: Display the composite section properties of the composite section including the parts, which became composite thus far.

Note 1
By checking the section properties of each part of a composite section, can we then detect any modeling error for a composite section.

Note 2
When construction stage analysis is carried out using Composite Section for Construction Stage, member forces and stresses can be checked from Results>Results Tables>Composite Section for C.S.