not only bridges
Looking at the maps in the article http://www.theatlanticcities.com/neighborhoods/2013/05/way-we-build-cities-making-them-flood/5590/ I found a report by the Chicago-based Center for Neighborhood Technology based on 177000 local flood insurance claims that found no correlation between damage and floodplains, as this graph shows:
It is a completely counter-intuitive result: are flood plains not always a good indicator of flood risk?
The main problem is that the flood decisions that local governments are making today not only determine how much damage future floods will cause locally, but also how healthy the community’s river and coastal areas will be. Chicago and its surrounding cities, for example, have artificially created flood-prone places simply by paving over the region's natural ability to manage excess water.
Impervious surface creates risk over a much wider area, and it is impossible to say that just because you are locally above the 100 year flood, flooding is not a risk.
1) Create geometry in AutoCAD or free alternatives (Draftsight, Nanocad,...). Explode entities if necesary to obtain only lines and save as Frames.DXF
2) Use gCAD3D (it is a free and open software http://www.gcad3d.org/), import Frames.DXF and save as Frames.IGS
3) Import parts as wires with Abaqus/CAE
1) Create geometry in AutoCAD or similar. Explode entities if necesary to obtain only lines. Separate and save as Contour.DXF and Partitions.DXF
2) Import Contour.DXF as sketch in Abaqus/CAE
3) Create part form sketch called Contour
4) Tools> Partition>Face>Sketch and use the sketch called Partitions
3D Shells and solids:
1) Create regions (command REGION of AutoCAD) and solids in AutoCAD and export as SAT (ACIS) file
2) Import parts as shells and solids with Abaqus/CAE
The latest procedure also works for planar shells but it is less precise.
Witness more than 42,000 hours of construction on the newly-opened Bay Bridge in just 4 minutes with this time-lapse video.