Footbridges are very important for the transport of pedestrians and cyclists. This footbridge design focus comes from the predicted demand for urban connectivity due to the rising number of people living in cities. Footbridge is one of the vertical separation facilities used to segregate pedestrians from vehicular traffic as a method of developing safety [Ribbens]. Only padestrians and people on bikes can use this footbridge. These are the user parts of the footbridge. This footbridge is planned to construct onto a highly frequented inner-city tram track. It is very important to connect the system with track line. The main design challenge to have proper angle and to have a column with enough capacity.

Ontology Model

The .owl file for the ontology can be found here.

Footbridges have generally 4 types of usage; bicycle, pipeline, pedestrian, ecopassage. Pedestrians and cyclists use the footbridges for passing through a tram track. Ecopassage is used by animals and plants and pipelines is used for the transportation of electricity or water. I examined and splitted the building into components; physical, functional and material. I developed my class hierarchy with the help of the reasoner tool of the Protege software. I examined the optimal values of the footbridges with the ontology design. During these assignment, I had to change my classes and the hierarchy. I encountered lots of errors related with the inconsistency, but in the end I succeded to eliminate them. It is very important to understand the reason of the inconsistency to create useful ontology.

Image 1 Footbridge Ontology

Parametric Model

The .dyn file for the parametric model can be found here.

The purpose of this parametric modeling is to understand the relation between a number of important parameters of a foot and cycle path bridge, its geometrical configuration and embodiment and a set of high performance criteria. According to Footbridge Vibration Design book ‘It is important to predict the effect of pedestrian traffic on footbridges at the design stage and in the later verification of serviceability in order to guarantee a comfort level for the user’ [Caetano et al.]. As stated here, these traffics will effect the design dimensions. According to Sacks et al. ‘Note that in parametric CAD systems, shapes are not only initially generated based on operations and constraints; the constraints are also maintained as an integral part of the model geometry during editing.’ [Sacks et al.]. Some 3D parametrization principles from Sacks et al paper are used in this assignment too.

The following parameters were selected as the ones to control the parametric model:

• Bridge Length
• Walkway Peak
• Bridge Cross Section Dimensions
• Middle Column Dimensions
• Bridge Ramp Angle

High Performance Criteria:

• Footbridge Middle Column Capacity
• Footbridge Ramp Angle

Image 2 Footbridge Parametric Model

References

[Ribbens] Ribbens, H., 1996. Pedestrian facilities in south africa: research and practice. Transportation research record: journal of the transportation research board, 1538: 10-18.
[Caetano et al.] Caetano E., Cunha A., Wasodew H. And Raoul J. “Footbridge Vibration Design” 2009.
[Sacks et al.] Sacks R., Eastman C. M., Ghang L. “Parametric 3D modeling in building construction with examples from precast concrete” 2004.