Selecting Bridge Section Shapes in the global data dialog allows you to either create a newly defined channel or select an existing channel from the global database.
If the bridge link is being defined from a pre-existing link, the existing channel will be used by default. The Bridge Hydraulic Openings dialog can be used to define the hydraulic openings above and below a bridge structure.
A Bridge's Low Chord elevation should be part of the Bridge Hydraulic Openings Cross Section Coordinate pairs.
All hydraulic openings are defined within the same dialog and consist of Cross Section Coordinates and at least one opening type data - the Culvert opening type can be used in addition to the Bridge opening type though at a minimum one Bridge opening type must always be used. For example, a bridge with piers and a culvert are shown above.
Bridge Opening Type:
The Reach Length is specified in feet (meters) and the Skew Angle is in decimal degrees (0-90). The other values in this dialog are all dimensionless. Entrance/Exit loss and Manning’s n values are discussed in the following Help sections though local guidelines and design requirements should take precedence.
Culvert Opening Type:
Culverts are defined by clicking Edit after selecting the Bridge/Culvert Data type as Culvert. Culverts can be modeled as Circular, Rectangular and User Defined. Conduit Factors can be specified similar to the Conduit Factors option for a single link conduit. A Circular Conduit opening type is shown below.
For Circular and Rectangular culvert shapes the following input data units apply:
Diameter: ft, m
Width: ft, m [Rectangular only]
Conduit Length: ft, m
U/S and D/S Invert Elevation: ft, m
Manning’s n: na