not only bridges

Flood simulations and actual flood risk

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: 


http://cdn.theatlanticcities.com/img/upload/2013/05/14/Screen%20Shot%202013-05-14%20at%202.06.51%20PM.png

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.

Tips for importing CAD into Abaqus or similar FEM software

Frames:
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

Planar shells:

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.

Official San Francisco-Oakland bay bridge construction video


Witness more than 42,000 hours of construction on the newly-opened Bay Bridge in just 4 minutes with this time-lapse video.

SAP2000 vs StaadPro

StaadPro is the most widely used bread-and-butter structural software in Asia and the UK while SAP2000 seems to be the most widely used one in Latin America, Portugal, Italy and Spain.

The grids provided in SAP makes it easier to create the geometric input than with the StaadPro. Dynamic analysis is stronger in SAP2000 (earthquake force applied in any direction, automatic lumping of masses for earthquake, live load reduction, bridges transient loads, eigenmodes and ritz modes, etc...). Sap2000 has facilities for creep and shrinkage of concrete. SAP2000 program has the ability to solve heterogeneous soil-structure interaction which is not possible in StaadPro. Also, SAP2000 can import the geometry and the material properties of StaadPro models, I am afraid that the opposite is not possible.

However, StaadPro has some great advantages. First and foremost, the license is cheaper. The connection with visualization and drawing software is much easier, not in vane StaadPro is a product of Bentley (Microstation, PDS, etc...). StaadPro provides additional modules for designing steel joints and foundations. The text editor facility for the model input file makes StaadPro is more versatile for model modification. It is possible to work with the ASCII file of SAP but it is cumbersome and it is necessary to leave the model and reload.

Now, the choice is yours.