Digital Terrain Model [CSB]

In bridge modeling, a Digital Terrain Model (DTM) refers to a digital representation of the natural surface topography of the earth, including elevation data but excluding man-made structures like buildings, roads, or vegetation.

• It shows natural features such as slopes, hills, valleys, and ground elevation.

• If man-made features are included, the model is referred to as a Digital Surface Model (DSM).

• DTMs can be represented using point clouds, Triangulated Irregular Networks (TIN), or raster grids.

DTMs play a crucial role in various phases of bridge design and engineering:

Site Selection and Design:

• Terrain elevation, slopes, and contours directly affect the alignment, span, and height of the bridge.

• DTM data helps engineers determine where the bridge should start and end based on topographical constraints.

Hydraulic Analysis:

• For bridges over rivers or streams, DTMs help model terrain slopes and water flow directions.

• This is essential for flood risk assessments and sizing bridge openings or culverts.

Earthwork and Volume Calculations:

• Knowing the terrain elevation at pier or abutment locations allows for accurate cut-and-fill volume estimates.

• Helps with construction planning and cost estimation.

3D Visualization and BIM Integration:

• DTMs provide the base for visualizing the bridge in a realistic 3D environment.

• They can be integrated into Building Information Modeling (BIM) workflows for enhanced project coordination.

Show [YES/NO]: This parameter allows the digital terrain model to be enabled or disabled.

Wireframe [YES/NO]: This parameter enables or disables the wireframe. A wireframe is a technique used in 3D modeling. It is a method where only the edges of a 3D object are shown, without filling in the surfaces. This technique displays the skeletal structure of an object, outlining its basic geometric shape.

A digital terrain model wireframe is a version of the terrain model where only the edges or boundaries of the terrain's 3D shape are shown. The elevation data is typically represented at specific points (control points), and the connections between these points are drawn as a wireframe, revealing the shape of the surface without much detail.

This type of model is especially useful in terrain analysis, visualization, and in Geographic Information Systems (GIS), as it provides a simplified yet clear view of the surface's geometry.