RM Bridge offers the flexibility to model and design any bridge structure type and construction schedule.
As a basic reference we create the structural 3D Axis, in Plan and Elevation, that is connected to the Road Alignment. For this Axis, we create the Cross-Section, and then we set how this will change in the development of the axis with the Segments tab where we can find Variables. What is different for Arches, Trusses, and Suspension bridges definitions, is that the user will have two possibilities:
- Create separated Axes;
- Define just one Axis and use the Variables.
The option depends on what needs to be achieved with the model. Despite the first option leads to simple usual Cross-Section definitions, in most cases, it is the second option that is used because it can deal with more complex variations as it uses only the road axis as reference defined at level 0, and then the Variables are used to create the difference to the other elements in the vertical direction. Then, the user needs to create a Frame with the different Parts independently, without connecting their Finite Elements to create separated elements, as shown in the images below. There will be two options for the Parts types at the definitions of the longitudinal elements:
- Normal: Deck elements and Arch are created as usual;
- Nodes: Links will be used from one point to the next in the Segment longitudinal direction.
In both options, the vertical and transversal elements, are created with Links and these elements have their own Cross-sections specified. The Variables are used inside the Cross-Section as a distance from a Reference line, as shown in the images below. Note that this option could be made in the main Cross-Section; so that it will then affect all included Parts, their respective Segments, and the Elements created from there.
For being used in the Segments, the Variables have to be previously defined, and this also could have two different approaches:
- Tables: by using final point-wide values, usually copied from .xls sheet, or;
- Formulas: with direct input or previously defined expressions.
For Arch bridges it could be any type of arch: deck arch, through an arch, tied-arch or bowstring arch, arch-suspension, arch-net. They can be steel, concrete, post-tensioned, cable-stayed and suspension, and pre-fabrication shapes can be included considering how they will be erected. The cantilever casting method for an arch bridge is a common use of RM Bridge and it can include temporary towers and cable supports as well as the incremental launching method.
For an Arch, the user can also use as reference the dataset and documentation you can find at File\Examples\Verification Examples and FAQ\ Modeler Link Segments & Truss Modeling as shown in the image and explained in the Wiki link below.