Model
Fig. The model tab of FCM Bridge Wizard
The model tab defines the composition of segments for creating the cross-section of the pier and the construction stages, taking into account the material of the bridge and the cross-section of the pier.
Material(Girder)
Material for girders
Pier Section
Section shape for piers
Material(Pier)
Material for piers
Click the [...] button to the right of the Material and the Pier Section to create new or modify the existing materials and section.
Stage Duration
Specify the time it takes to install the formwork; place the reinforcing and sheaths; and cast and cure the concrete (i.e., the total time to construct a segment that constitutes a construction stage). In the case of cast-in-place concrete, the Stage Duration must be greater than the Member Age of the segment being cast (activated) in the corresponding construction stage.
Number of Piers
Total number of piers (a twin pier is counted as one)
Method
Cast-in
Select this option if the bridge is constructed using the cast-in-place construction method.
PSM
This option is selected when using the Precast Segment Method (PSM) for construction with precast segments. There is no restriction that the duration of the construction stage must be longer than the initial age of the segment, and the self-weight of wet concrete is not considered.
Radius
Check on to specify the radius of a curved bridge with a single curvature.
Convex
Convex curvature bulging to the general +ve direction of the Global Y-axis on the Global X-Y plane starting from the GCS origin tangent to the Global X-axis
Concave
Concave curvature bulging to the general -ve direction of the Global Y-axis on the Global X-Y plane starting from the GCS origin tangent to the Global X-axis
In previous versions, the value of Radius was expressed as + or - to reflect the curvature. In this version, Radius is always expressed as a positive value, and instead, Convex or Concave can be selected to reflect the curvature of the bridge.
Pier Table
P.T. , B
Specify the top and bottom dimensions of the pier table referring to the guide diagram.
Advanced Pier Table
The number of diaphragms and the dimensions of the pier table are specified for each pier separately.
Fig. Advanced Pier Table
The list of the same number of pier tables is automatically generated on the basis of the Number of Piers entered in the above dialog box. The following items can be specified after assigning the desired pier tables requiring data changes:
Pier Table Type
Referring to the guide diagram, select the diaphragm type, and enter the shape and dimensions of the pier table. A non-symmetrical FCM bridge may be modeled by specifying different dimensions at the left and right.
Define
Apply the data entered in Pier Table Type to the assigned pier tables.
Delete
Initialize the data by deleting the entered data for the assigned pier tables.
Key Segment
K1, K2
Referring to the guide diagram, enter the lengths of the key segments (linking elements).
Advanced Key Segment
Enter the length of each Key Seg. and the number of prismatic segments (straight section zones) on each side of the Key Seg.
Advanced Key Seg.
A number of Key Seg's. relative to the number of piers are automatically generated and listed in the dialog box. Enter the following items after selecting the Key Segs. whose data are to be changed:
Key Segment Length
Length of Key Seg.
Left Straight Segment No
The number of prismatic (straight) segments to the left of the Key Seg. At least '1' is recommended for the Key Seg formwork.
Right Straight Segment No
The number of prismatic (straight) segments to the right of the Key Seg. At least '1' is recommended for the Key Seg formwork.
Define
Apply the entered data to the selected Key Segs.
Delete
Initialize the data entries by deleting the entered data for the selected Key Segs.
Pier
H, C
Referring to the guide diagram, enter the height and the spacing of the twin pier.
A single pier can be modeled if the spacing (C) is defined as '0'.
FSM
The FSM zone is considered as one segment. To specify tendon anchor locations define the lengths of the elements. The FSM zones are conventionally constructed with full shoring (FSM, Full Staging Method).
Confirmation is required as to whether or not the elements in the FSM zones will be divided. If it is not divided, all the tendons will be anchored at the same endpoint. This functionality is added to avoid analysis errors related to anchoring bottom tendons at a single element.
Fig. Confirmation message when FSM information is empty
Zone
Specify the lengths of the segments in the buttress span (Zone 1) and the interior span (Zone 2). Enter the lengths from the closest to the Pier table to the farthest from the Pier Table.
Advanced Zone
For each pier table, enter the lengths of the left and right segments. This feature becomes handy when the FCM bridge model involves non-symmetrical configurations or the spans vary.
Advanced Zone
The dialog box displays the auto-generated list of segment lengths based on the number of pier tables. Select the pier tables that require length changes and input the following:
Zone1, Zone2
Lengths of the segments located to the left and right of the first interior pier table.
Zone 1 represents an end span, and Zone 2 represents the interior spans (when the Advanced Zone option is checked off). If the Advanced Zone option is checked on, Zone 1 and Zone 2 represent the segments to the left and right of each pier table respectively.
Curvature1, Curvature2: Exp.
The highest exponents of the curvature equations define the variable sections of the left and right segments in Zone 1 and Zone 2 respectively on each side of each pier table. The exponent ranges between 1 and 2.
Define
Apply the entered data to the selected Pier Tables.
Delete
Initialize the data entries by deleting the entered data for the selected Pier Tables.
The Advanced Zone dialog box enables us to incorporate changing spans and model an FCM bridge constructed non-symmetrically. The construction stages are automatically composed in the process. The numbers of left and right segments must be equal. Also, all the piers must have equal numbers of the left and right segments although their lengths may be different. The geometry is defined for each "T" shape (left/right cantilevers and a pier) separated by the Key Segs.
Pier Table Placing
In practice, not all the pier tables are constructed simultaneously. For this reason, we specify the relative times (time differences) for constructing the pier tables. The pier table at the farthest left pier retains the number 1. The entered Days determine the construction stages.
In FCM bridges, it is difficult to install each pier simultaneously, which affects the construction schedule of cantilever sections. Therefore, when fastening the Key Segment, there is already a difference in member ages between the cantilever sections on both ends. Pier Table Placing is defined to reflect this age difference in the analysis. In the Pier Table Placing dialog box, when you input the construction time difference according to the construction schedule, midas Civil applies additional member age (Time Load for Construction Stage) equal to the construction time difference to the elements of the main pier and cantilever sections that are constructed first.
Member Age
Specify the initial age, which is the maturity of concrete at the start of a construction stage (i.e., aging of concrete taken place in the immediately preceding stage). The member age is used to reflect the compressive strength (modulus of elasticity), creep and shrinkage. (Input unit: Day)
The initial age represents the duration of curing in-situ concrete subsequent to installing re-bars and formwork/falsework and casting concrete. The actual aging takes place in the latter part of (n-1)th stage, and that duration becomes the member age at the start of the nth stage.
FCM Wizard Automatically generates Element groups, Boundary groups, and Load groups to create a bridge model. Refer to Define Structure Group, Define Boundary Group, and Define Load Group.