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  Generic Model Creation 

Example: Bridge Double Curves Deck (RH, RV)
ICDAS YouTube Channel   ICDAS GEN 2024.00R 

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Model description


BIM model

Analysis model






















This example is a part of ICDAS Manual for bridges creation by manual hand-click using in combination with automatic model creation. The example demonstrates a double curved concrete bridge in Revit using ICDAS Generic Model Creation, including:


    Concrete box deck with two voids. The box depth-to-span ratio is 3.4% (=5/145=1/29)

    Pier columns, foundation, people and vehicles are loaded from ICDAS Bridges Library.    

    Alignment is a double curves (RH, RV) where RH is horizontal radius and RV is vertical radius.


Figure: Floor Plan ‘STL’. 

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Above shows the green horizontal alignment RH 2000m in YX-Plane, the blue vertical alignment RV 1003m in ZX-Plane, and the 3D red alignment R 897m is the station line (STL) along the bridge deck.

(RH, RV) are chosen small for demonstration reason, both have the curve length of 200m. Note that the vertical height of arc 5000mm is double the horizontal 2502, as the RV is a haft of RH. They are the key inputs for the bridge below.


Figure: Floor Plan ‘PVT at Elev. 0’ (top) and Longitudinal section ‘LG’ (bottom).

The above figure shows the bridge geometry created by ICDAS Generic Model Creation at Project Base Point (0, 0, 5000)mm (PBP).


Once the real global coordinate and the angle to the North are known at PBP, they are entered at PBP in Floor Plan Site View. Hereby the entire 3D BIM model is updating after the new coordinate system including all 2D sectional drawings created in the project.

The above figure the longitudinal section (LG) is located 9300mm from the edgebeam, and go through the right-side void of the deck. The LG is a rectilinear section which cut the double curved void in the deck. As the result, the void does not have a constant dimension in the LG vertical view, as shown above.


As the RV 2003m is extremely small over the short curve length 200m, the tangent slopes on the two sides reach the maximum permitted 10% grade. 


Figure:  Two sections needed for the deck profile.

To design profile of deck in the double curved alignment, two sections are needed to get the inclining reference plane for the deck at the start. The first, named ‘S1 for Profile’, create to follow a short tangent to RH curve at the start of deck in Floor Plane. Once created, go to this view see the deck in vertical direction. Create an inclining Ref. Plane named it ‘Profile’ at the deck start (the dash surface). Create the 2nd section named ‘S2 in S1 for Profile’ parallel to this Ref. Plane ‘Profile’. The section ‘S2 in S1 for Profile’ is the view where the deck profile has true dimensions in both horizontal and vertical direction, as shown above in orange values (mm).



The deck box is constructed as a double-boxes carrying by two independent columns (bearings are not inserted). They are connected by 2m in cross direction. The top of deck has one-sided 2.5% slope as the alignment horizontal curve RH 2000m. The bottom of deck is parallel to the top in 5m perpendicular distance, to provide a depth-to-span ratio of 3.4% (5/145) as an experience ratio for concrete bridge (post-tensioning). The two voids of 3m diameter significantly reduced the deadload vertical deformation for the center span of 145m.


Figure: Section S3 and Pier dimension in Floor Plane.


Go to the Floor Plan view, select the section 3 and drag ‘Far Clip Offset’ to the end of bridge, then go to this view for the above figure (left). In this view the blue vehicle see the white vehicle in only 70m distance as the small vertical alignment RV 1003m, therefore the vehicles speed are permitted to 50km/hour, also as a rule for the upgrade of 10%.


The pier is designed 4m width on top to fit the bottom of deck in cross direction, but turn to 5m width at the bottom in bridge direction. The thickness increases also from 1m on top to 2m at bottom. It provides the stiffness against bending about the global Y-axes for the column of over 20m height.


This file is one of many in ICDAS Bridges Library which provide a draft for an actual project. It can be a stretch of long link of bridges. In use with project, the known STL and the deck profile are modified using ICDAS Manual for Bridges, where the other bridges can be created automatically. Note that Revit intelligent model-based technology includes i.a. that all models (bridges) are stored in one file for the project that the user can double click on one model to open and modify it.  


Figure: Perspective view including two vehicles.


Figure: Perspective view where the white vehicle is not in sight as the small vertical alignment RV 1003m.


Figure: Perspective view highlight the pier strong axes at bottom. 

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123456789_123456789_1123456789ICDAS  •  Hans Erik Nielsens Vej 3  •  DK-3650 Ølstykke  •   E-mail: th@icdas.dk   •  Tel.: +45 60 53 83 79  •  CVR no.: 34436169