On December 2018, ICDAS has successfully developed a new workflow of Autodesk software for bridges design on aerial map from the start of any project. To demonstrate concept of the workflow, a 2.8km fixed link proposal between Broager Denmark and Halbinsel Holnis Germany is projected as an example. The example includes also some guidelines for ICDAS Automatic Bridges Creation CSB and COB in Revit.
The fixed link proposal will reduce the distance between Sønderborg and Flensburg to 31km from 46km as shown in the image above. In addition, if the two roadways of length 10.4km and 18.3km on Denmark and Germany side also upgraded to 110km/h to the link, then a car will reach Flensburg from Sønderborg in approx. 17 minutes driving.
The workflow starts in InfraWorks to determine an area of interest on earth (AOI), which can be up to 200km2, including digital shapes of existing buildings, roads, terrain elevations and landscape. A road with associated alignment is first designed in InfraWorks/Civil3D to provide (X, Y, Z) points of alignment for the ICDAS Bridges input.
The bridge is then automated in Revit using ICDAS CSB and uploaded on InfraWorks aerial map for that alignment. This uploading is within a minute or faster depended on size of the bridge.
Before uploading on aerial map, the user can further name the AOI e.g. CSB (Cable-stayed Bridge proposal) to keep the ‘master’ AOI empty. Thus, the user can return to the master to create a new proposal, e.g. ARB (Arch Bridge). Once both CSB and ARB uploaded, they can just be switched by a single click.
The images above shown the Cable-stayed Bridge loaded in InfraWorks on top view and 3D. Thus, in addition to the power of ICDAS automatic models creation in Revit (and FEM LUSAS), the user can now present the proposals in high resolution aerial map through cloud services, which visualize the models in realistic graphics faster than ever.
In the images above only the cable-stayed bridge and the approach bridges are modelled in the link. The bridge starts (station) at the end of Nejsvej on Broager side, and end at Holnisser Fährstrabe on the Holnis side. InfraWorks detects name of the road when you place mouse cursor on it, i.e. they can be modified to fit dimensions of the new link of 6 lanes (using InfraWorks add a component road). InfraWorks interface is easy to rotate, pan and zoom even with the landscape area including digital buildings, roads and terrain elevations. In InfraWorks all buildings are modelled simple with the outer shapes only, but theirs digital positions are valuable for further modelling, especially the digital networks of roads provide the input for ICDAS Bridges to give proposals for bridges/infrastructures at almost anywhere in the world.
Revit materials rendered in InfraWorks cloud services
Revit materials appearance assigned to the bridge generic objects will display differently when uploaded and rendered in InfraWorks cloud services. Refer an ICDAS Bridge subscription for further details in this regards.
InfraWorks applies coordinate system LL84 (Latitude, Longitude, Elevation) at the lower left corner by default. Go to Settings and Utilities > Model Properties and switch to UTM-32N coordinate zone for Denmark. Ensure Civil3D and Revit use the same UTM-32N system. Refer an ICDAS Bridge subscription for further details in this regards.
For the concept of BIM+GIS workflow reason, drag a simple rectilinear road component (horizontal alignment) in InfraWorks from the end of Nejsvej on Broager side to Holnisser Fährstrabe on the Holnis side (not shown).
Vertical alignment
The above figure shows the 1st draft og vertical alignment (Profile View) once the component road created in InfraWorks. For the concept of BIM+GIS workflow reason, there is no profile for the existing seabed taking into count. The vertical alignment of the road is easily to modify by selected a point of vertical intersection (PVI, the triangular grip). A Revit 1st draft of extrusion columns has been uploaded on InfraWorks along the alignment for further modification of the alignment. Here the 1st configuration for the alignment is 670m approach bridge + (500+1000+500)m cable-stayed bridge + (65+65), starting with station ST. 0 on the Broager side, end at ST. 2800 on the Holnis side. The vertical curve is summarized below (enlarge the image above in a new window for resolution 2799x1610 pixels).
1. Set curved length 580m at center main span station 1670, the K-Value calculated automatic to 100 (i.e. R approx. 10000m), where Grade (In, Out)=(2.5, -3.3)%
2. Set curved length 100m at pylon B, ST. 1170m, the K-Value calculated automatic to 425.455, Grade (In, Out)=(2.26, 2.50)%
3. Set curved length 100m at pylon H, ST. 2170m, the K-Value calculated automatic to 606.336, Grade (In, Out)=(-3.36, -3.52)%
This vertical alignment of the temporary road will be used in the next InfraWorks proposal for the cable-stayed bridge and the approach bridges link through Civil3D Alignment (Station, X, Y, Z) report.
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Figure 6. Civil3D Alignment (Station, X, Y, Z) to ICDAS Bridges input
In Civil3D open the IM_Export.imx exported from InfraWorks ‘Broager-Holnis link’ then create report for the road alignment shown above (left) where (X, Y) coordinate are in UTM-32N zone for Denmark. Copy columns ‘Station’ and ‘Elevation Design Z’ to ICDAS input for Bridge (right). Set Y=0 as the horizontal alignment is rectilinear in this case. In Revit rotate the bridge in angle to the true North so it fit Broager – Holnis in InfraWorks.
Revit model in global UTM-32N
Figure 7. Revit model in UTM-32N
Follow the red steps in figure above:
1. In ICDAS Bridge the deck cross section start input at point 1 bottom of deck (it is freely for the user to start on top of deck). Point 1 start at ST. 0, where Z=6m in XYZ-Alignment input, and where MoveVer = -2m has moved the entire deck 2m up (in ICDAS input above, negative side upwards in ICDAS profile coordinate). Thus, the bottom of deck is 6+2=8m as shown in 1/.
2. Once the deck rotate to fit Broager – Holnis in InfraWorks, it moves (dx, dy)=(5.305, 10.874)m from Project Base Point (PBP) in Revit.
3. Adjust (PBP_N, PBP_E)=(N+dy, E-dx) where the coordinate (N, E) is obtained from Civil2D at ST. 0.
4. Enter (PBP_N, PBP_E) in Revit Project Base Point (unit is in mm). Keep (Elev, Angle to True North)= (0, 0) as they are controlled by Z-Coor and the above rotation.
5. To control the result, check the Revit global coordinate (N, E) at ST. 40m which is agreed to Civil3D, and the bridge fit Broager – Holnis in InfraWorks.
Thus, the bridge already is in the global coordinate UTM-32N at this step. Note that ICDAS works on geometry with rather focus on the stations along the deck than the (N, E) coordinate. However, at any created section (view), even in 3D view, the user can click ‘Spot Coordinate’ and ‘Spot Elevation’ at any point along or across an edge of a 3D object in the bridge.
The Cable-stayed bridge is designed with simple open V-shape pylons harmonizing to the open sea at Broager-Holnis landscape. InfraWorks provides the aerial map with digitalizing buildings, roads and terrain elevations. Mouse on the road ‘Rødegade’ above the user can further link to OpenStreetMap (click on image to enlarge). For terrain elevations InfraWorks will display with contours and the white values. Note that the big natural area with high trees is displayed in plane (e.g. elevation 20m at the lower left corner), but all big buildings and roads have theirs real elevations. Also for demonstration of the workflow reason, all levels in this proposal are valid from the water elevation 0. Once the geotechnical reports for the seabed are available for the project, the user can easily modify the lower part of the pylons and the piers in ICDAS parametric input, create Revit model again and reimport in InfraWorks.
Choosing spans (460 + (570+1140+570) + 60)m, only a pier on the Holnis side is on the water, whereas all other piers are on the mainland Denmark and Germany. The cable-stayed bridge (570+1140+570)m has a streamlined steel box girder, whereas the two approach bridges having concrete box deck of 460 and 60m length on the Broager and the Holnis side, respectively.
In the Longi View there are only the last two cables on each side span are fixed in vertical direction and partial longitudinal direction to the piers, the so-called ‘earth-anchored cables’. On the Broager side they are the next last cable fixed to top of pier B1, and the last cable fixed to center of span B1-B2. These two fixations have the purpose to reduce the pylon top displacement towards the center of bridge for the traffic loads placing on the main span only. As the outer most cables are longest with biggest cable sag, they do not effectively provide the wished support for the pylon top. Therefore, in many cases of the cable-stayed bridges there are more than two cables needed to be fixed to the piers, especially for the short side spans, i.e. more piers needed to be built on the side spans. In this proposal the side spans are perfectly symmetrical to the main span, i.e. the are no longitudinal displacement at pylons top at deadload condition. However, once the analysis model revealed that more side piers needed for the traffics, it is easy to load more piers to the BIM model. This issue is not discussed further here to keep the workflow of BIM-GIS integration in focus.
Table 1: Key data of the link.
Dimension
(m)
Note
Main span
1140
New world record (pt. Russky Bridge main span 1104m, Russia 2012)
Side span
570
Streamlined steel box side span in association with the cable-stayed bridge.
525
Distance to the first pier.
New world record (pt. Hutong Bridge side span 462m, China 2019)
Total length
2800
(460 + (570+1140+570) + 60)m
Clearance
460 Width
40 Height
Pylon height
336
New world record (pt. Millau Viaduct 335m, France 2004)
hang-to-depth ratio = 30/4 = 7.5 (cable-stayed deck)
4 (concrete)
span-to-depth ratio = 76/4 = 19 (concrete box deck)
Number of lanes
3 + 3
2 traffic lanes a 3750mm + 1 Emergency lane 3300mm
Dimensions in BIM models
As ICDAS Bridge is BIM model including 3D objects with theirs edges, all dimensions are available in association with the 3D objects at the edges. I.e. the user can create any section (view) of the bridge for the dimensions. In this proposal only the key dimensions are outlined.
All dimensions in Revit cross sections above are given from parametric INPUT BRIDGE EXCEL.xlsm (steel deck) and INPUT GEN Excel.xlsm (concrete deck) where the bridge is entirely automated by ICDAS. There is no additional modification needed, except bearings, vehicles and people are loaded to project from ICDAS/Revit libraries.
Revit allows the user to measure two cross sections in one view, here the steel box and the concrete deck box at station 460. Follow the red steps 1, 2, 3 in the views above to apply the ‘Far Clip Offset’ for 3D dimensions.
1/ In Site view (top view) move the section B2 200mm to the concrete side so B2 see both concrete and steel deck cross sections, the edges of objects.
2/ Drag ‘Far Clip Offset’ of B2 37.5m toward Holnis so B2 see also the two cables L and R go down to the deck (the left and right cables are for looking in stations direction from Broager to Holnis)
3/ Go to view B2, the two cables L and R are there, and view B2 see both the steel box and the concrete deck cross sections. As the edges of objects for both cross sections are including in the View B2, we can measure dimensions for them. Thus, we work always in 3D in Revit. A ‘2D’ cross section dimensions is where we set ‘Far Clip Offset’ to 5mm, and make sure that the view B2 see only one cross section (by move and change direction of view).
In the new ICDAS Bridges 2019 workflow Revit and InfraWorks are concurrently applied. Dimensions are designed, modify and measure in Revit, then upload on InfraWorks cloud services for rendering, visualizing and animating.
Visualization and navigation in InfraWorks is not just easiest and fastest, but it is also to control position of the construction on site. Especially zoom to enlarge details of the construction in InfraWorks is more convenient than in Revit 3D views.
The above images shown the concrete box deck designed in the same slopes of the streamlined steel box, on top and bottom of the two inclining sides.
The piers have circular cross section on top, but ellipse at bottom to increase the require bending stiffness.
Figure 14. Top View PylonB. Dimensions at pylon leg top and bottom.
The record height 336m pylon is designed to meet the need of 29.5% the record length 1140m of the main span. The pylon legs are designed with increasing cross section towards the bottom to provide the required bending stiffness and to carry the accumulated compression from the stayed cables and the pylon's own deadweight.
All dimensions for the pylon are given from parametric INPUT BRIDGE EXCEL.xlsm where the voids in pylon legs are not yet inputted, and where the pylon is automated by ICDAS. There is no manual modification needed.
In figure 13, the cross beam 53532mm length is concrete prestressing to keep the two inclining legs in stable. The internal cross distances between the two pylon legs from top to bottom are respectively (87000, 53532, 25340, 19000)mm. The distance 25340mm at the deck is fixed as the requiring space for the deck. It is obtained by parameter inputs (EccL, EccR) as eccentricity to the left and right from center for the two pylon legs, at the top and bottom.
In figure 14, the ICDAS Bridges provide 12 parameters (a1-a3, b1-b3, c1-c3, d1-d3) to design the pylon cross section on the top and at the bottom. The top dimensions (8m, 7m) are increasing to (16m, 11m) at the bottom. At the bottom, c3=4m against c1=2m to increase the weight toward the center to improve the balance for the outwards inclining legs.
FEM statics & dynamics analyses
A FEM LUSAS model created also automatically in ICDAS CSB concurrently with Revit model. The automations include also all loads on bridges, smart combinations of envelopes and the opposite to search the worst combination of actions on the bridge. Verifications of concrete, reinforcement, prestressing cables, steel cable-stayed and the steel deck box will be according to the criteria from the Danish Road Directorate and Eurocode, in SLS, ULS and ALS. These issues are not outlined in this workflow for BIM+GIS integration.
Concluding remarks
ICDAS BIM+GIS integration has open new opportunities to design bridges on site. A big work of the bridge’s alignment and the bridge BIM model can be done within short time. From which, the project development will always be on the real alignment, as a wish for all involved in a bridge project. In addition, ICDAS automatic bridges creation provide unlimited design proposals fitting to the terrain condition, at the preliminary state, during the project justification and the final construction as well.
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