A vast amount of effort has been spent on the development of the new bridge routines used in the HEC-RAS software. The bridge routines in HEC-RAS allow the modeler to analyze a bridge by several different methods with the same bridge geometry. The model utilizes four user defined cross sections in the computations of energy losses due to the structure. Cross sections are automatically formulated inside the bridge on an as need basis by combining the bridge geometry with the two cross sections that bound the structure.
The HEC-2 program requires the user to use one of two possible methods, the special bridge routine or the normal bridge routine. The data requirements for the two methods are different, and therefore the user must decide a prior which method to use.
Differences between the HEC-2 and HEC-RAS bridge routines will be addressed by discussing the two HEC-2 bridge methodologies separately.