Defining Build Bridge Opening for HEC-RAS Bridge Modeling

In GeoHECRAS, the Build Bridge Opening data panel of the Bridge & Culvert Data dialog box allows the user to define the geometry of the bridge opening by using span or abutment data. This article describes how to use the Build Bridge Opening data panel.

Follow the steps below to use the Build Bridge Opening data panel:

Select the Build Bridge Opening option from the Roadway Crossing Specifications dropdown combo box of the Bridge & Culvert Data dialog box.
The Build Bridge Opening data panel will be displayed.

The following sections describe how to interact with the Build Bridge Opening data panel of the Bridge & Culvert Data dialog box.

Bridge Opening Geometry

In this section of the data panel, the user can enable either the Define Opening by Span or Define Opening by Abutment radio button for the selected bridge opening geometry. Clicking the [Pick] button next to the Low chord elevation entry field allows the user to select the low chord elevation from the roadway crossing plot. Note that there are two tabs at the top of the geometry table that correspond to the upstream and downstream faces of the bridge opening. The user can copy the chord elevation data from the downstream bridge opening to the upstream bridge opening (or vice versa) by clicking on the [Copy to Upstream Bridge Opening] button.

Define Opening by Span: On selecting this radio button option, the user can define the geometry of the bridge opening by using span data. The user can choose the desired opening span reference station from the dropdown combo box. Clicking the […] buttons next to the reference station entry field allows the user to pick the reference station from the Map View and roadway crossing plot, respectively. Clicking the […] buttons next to the Opening span (width) entry field allows the user to measure the bridge opening span from the Map View and roadway crossing plot, respectively.
Define Opening by Abutment: On selecting this radio button option, the user can define the geometry of the bridge opening by using abutment data. Clicking the […] buttons next to the Left abutment station and Right abutment station allows the user to pick the leftmost and rightmost abutment stations from the Map View and roadway crossing plot, respectively.

Defining Sloping Abutments

This section allows the user to define the sloping abutment data. The user can check the Define Sloping Abutments checkbox option to allow the software to enable this section for defining the sloping abutment values.

Clicking the [Pick] button next to the Offset below low chord entry field allows the user to measure the vertical offset distance from the bottom of the bridge low chord to the top of the sloping abutment. The Side slope (V:H) entry field defines the side slope of the abutments.

Defining Piers

Selecting this checkbox option allows the user to define the pier width and pier span centerline spacing data. This section of the data panel allows the user to enter and edit bridge pier centerline spacing across the roadway crossing cross section.

Clicking the […] buttons next to the Pier span centerline spacing entry field allows the user to measure the pier span centerline spacing from the Map View and roadway crossing plot, respectively.