Transverse Analysis Model

 

 

Automatically generate a transverse analysis model from the frame of a bridge in the primary direction. Upon selecting a point in the primary direction, the Wizard generates a 2 dimensional Frame model, which intersects the point. And this generates the section properties for analysis. In addition to the geometrical section properties, the user can also assign loads (such as dead load, live load, etc), tendons and reinforcement to the elements.  

 

 

 

From the Main Menu select Structure > Wizard > Transverse Model

 

 

 

  Selection Position

Element: Select elements for which transverse models will be created.

Grillage Model (PSC-T shape only): When using a Tee-section grillage model, its design should consider the transverse section of the entire bridge. By selecting this option, the program creates a transverse section for the entire bridge. However, this only applies to the PSC Tee-girder sections.

After selecting this option, if the user selects the elements that compose the transverse section in a particular order, the program automatically generates the entire transverse section by connecting the sections in the order they were selected.

 

Position

Select the node position (or node) for creating the transverse section model.  By clicking on the   button after selecting the elements and position, the selected elements are listed, and the transverse frame appears in the View Dialog box for preview. The preview is useful for inputting tendons and reinforcement. X indicated under the data part of the list indicates that the information for creating the transverse model has not been entered. After entering the information in Model, Load and Tendon & Reinforcement tabs, and clicking on the    button, O is displayed, which signifies that the transverse model is ready to be generated.

  Selection Position

Shape: Displays the assigned sections of the selected element. The data inputted in Transverse Analysis Model Wizard (Model, Load, and Tendon & Reinforcement) should be based on the shape indicated in the Section.

 

  •  Model tab

 Input the geometric properties for the transverse section model..

Longitudinal Length: Longitudinal length of the transverse section model.

Maximum Mesh Size: Maximum mesh size for the transverse section model.

Boundary Condition: Type of Boundary condition.

Boundary condition is defined for every node at the bottom of the section. The left-most side node is defined as a hinge and the other nodes are defined as roller.

Support: Define boundary condition as a Support

Spring: Define boundary condition as Point Spring Support.

 

 Pavement & Barrier

Define the section of Pavement & Barrier.

Type: Select the transverse shape.

Slab Width: The slab width of the section shape selected above is displayed. This cannot be modified.

b1~b7: Define the length by referring to the figure in the dialog box. These are the positions where the loads are applied. Assigning the length as zero is allowed.

Sum: The sum of b1~b7 is indicated.

 

 Change the Section Offset

It is invoked if a section offset is assigned to the Top or Bottom flange for the creating the transverse model. If the transverse model requires a tendon, selecting Center Top for the top flange offset is convenient, since the coordinate of the tendon is inputted based on the axis of the flange element.

Top Flange/Bottom Flange: Assign the section offset to the section of Top and Bottom flanges.

Center-Top/Center-Bottom: Assign Center-Top to the top flange section and Center-Bottom to the bottom flange section to generate the section offset.

Offset Distance: User defined offset distance is assigned to the flange section. Top flange offset distance is measured from the top of the section, and Bottom flange offset distance is measured from the bottom. The offset distance is based on the center of the section.

Consider Joint Offset of the Flanges and Webs

This option is checked if the rigid zone of the flange web intersection is considered.

Reverse Local-y Axis

The section will be reversed by local y axis.

The figure shown below is an unsymmetrical Tee section.

A model will be created as shown below, if the section shown above is created as a transverse section model by selecting the Reverse Local-y Axis. The figures below show the front view created by the Wizard with "Hidden" applied.

  •  Load tab

Assign the load information                         

Self weight: Self weight

Pavement: Weight of Pavement.

Thickness: Thickness of pavement

Unit Weight: Unit Weight of pavement

Barrier: Weight of barrier. Input "Section x Unit weight" In the transverse model, the thickness of the barrier is considered when assigning the load.

Unit Load: Self weight of Barrier

Additional Load: Additional load on the barrier due to sound proof wall, or railing.

Median Strip: Self weight of median strip. Input "Section x Unit weight" In the transverse model, the thickness of the median strip is considered when assigning load.

Collision: Assign load due to collision.

Height: Assign height of collision.

Side Walk: Self weight of Side Walk

Thickness: Thickness of Side Walk

Unit Weight: Unit weight of Side Walk

Crowd load: Pedestrian load.

Handrail Force: Calculates the load when a person is leaning on the hand rail. The size of the load and the distance between the top flange and the load are inputted.

Temperature

Delta T: Distribution of heat and temperature difference of the top and bottom surface.

System Temperature: Load caused by temperature

Live Load

Assign the moving load for transverse analysis.

P: Wheel load

n: Number of lanes

De: Minimum distance of the wheel to the barrier or the median strip.

Dw: Distance between two wheels

Dv : Wheel distance between two vehicles.

: Load reduction factor to be applied when vehicle loads are loaded on a number of traffic lanes.

: Load reduction factor to be applied to a position on the transversal section.

Wind Load

Input wind load data

Distributed Load on the Web: Uniformly distributed load on the Web

Horizontal Load on the Barrier: Lateral load acting on the barrier

Moment due to the Barrier: Moment occurring on the barrier due to the lateral load.

Direction: Direction of the wind load.  

 

  •  Tendon & Reinforcement tab

Assign tendon prestress and reinforcement information.

Tendon

Tendon Property: Select tendon property. In case the predefined property does not exist or when the existing property needs to be modified, click on the […] button to the right.

Numbers: Enter the number of tendons in the primary direction. This is the number of tendons that are included inside the primary length inputted in the Model Tab.

Prestress Load: Enter the prestress load. This can be inputted as force or stress.

Direction: Enter the direction of the stress.

Curve Type

Spline: Calculate the minimum polynomial curvature connecting the points defining the tendon profile and automatically place the tendons.

Round: Place the tendons in along a circle, which form tangents to the straight lines connecting the points defining the tendon profile.

Profile Insertion Point

Input the starting coordinate of the tendon based on the coordinates created from the beam element corresponding to the top flange.

x-axis Direction:

This is the x-axis that is defined for locating the tendon.

Profile

Place the tendon profile by defining the coordinates of the tendon. The tendon coordinate system (TCS) used here is temporary, and its origin is the starting point of the tendon, which will be related to the elements by the profile insertion point. As many coordinates as required to define the profile may be specified, but at least two (start and end) points are required. The x-axis of TCS is parallel with the Global axis in the longitudinal direction, and the z-axis of TCS coincides with the Global Z-axis. See Tendon Shape below for further details.

x, y, z: tendon coordinates in TCS.

fix: check on the box to specify the tangent to the tendon curvature at the point in question.

Ry: if "fix" is checked, the angle of the tangent line relative to the x-axis in the TCS x-z Plane.

Rz: if "fix" is checked, the angle of the tangent line relative to the x-axis in the TCS x-y Plane.

 

 Reinforcement

Assign reinforcement in the transverse direction.

Assign Element

Select the elements to assign transverse reinforcement. The elements are selected by first clicking on preview and then clicking on . The number of the selected elements is then assigned automatically.

         If all the elements are selected, then without clicking  all the element numbers are automatically inputted.

Cover Thickness

Input Cover Thickness after deciding if top or bottom reinforcement is needed.

Size

Select the diameter of reinforcement.

Numbers

Input the number of rebars in the transverse direction.

Longitudinal Space

Input the longitudinal spacing for transverse reinforcement.

After inputting the information by clicking on , "O" is displayed on the data list of the elements. After "O" is confirmed, click on the    button to create a transverse model file. The transverse model file is saved in the same folder where the current primary direction bridge model is saved. The file will be saved as follows:

(The file name of primary direction model)_(Element number)-(i or j).mcb

For example: FCM Bridge_14-i.mcb

   Defaults all the values.  

 

Revision of Civil 2014 (v2.1)

Q1. I am working with the "Transverse analysis model wizard" of midasCivil. I already did the model of the bridge I am working on, using PSC elements. The girder is a simple box which has to be analyzed longitudinal and transversely for its subsequent design. As far as I could see, both analysis (long. and trans.) are made separately by midasCivil, then when I use the "Transverse analysis model wizard" it creates a 2D model of the transverse section selected. At this point, I am having issues with the definition of the moving loads. The input data is simple; but not very good explained in the on-line manual. For instance, when defining the vehicles, there is a value "Distribution width W:" I don't know what it refers to. Additionally, I need to define 3 vehicles and get the involvement of these 3 loads; but it's not possible to define more than 1 vehicle. On the other hand, I am working with the load cases LM1, LM2 and FLM2 (Lorry 3) of the Eurocode. Consequently, I don't know how to define these load cases for the analysis of 1m long of the transverse section in midasCivil. I would like to have more detail explanation and an example of application of these loads. In the same way, I did a hand calculation using Homberg charts and FEM to get the evolvement of the moments in the transverse section, but the results are completely different from those given by midasCivil. I attach the file I am using with the moving load LM1 of the Eurocode. I am not sure about if I did it okay because I assumed many things to define the loads. It suposse to be applied max. 2 lanes of loads, the first one using a load for each wheel equal to 150 [kN] and the second one using a wheel load equal to 100 [kN]. Please check the Eurocode 1991-2, pag. 35.