"Mathematica provides an excellent environment for writing powerful programs with just a small amount of effort," says Shantz. "Now it's like my right arm because all my routines are in there."

Preparing the Bay Bridge for the Earth's Next Tremble

Civil engineers at Caltrans, the California Department of Transportation, are hard at work upgrading highway structures throughout the state to withstand future earthquakes. Thomas Shantz, in particular, has turned to Mathematica as he works on a seismic retrofit design for the Bay Bridge, which crosses the San Francisco Bay to connect Oakland and San Francisco.

To strengthen the bridge, Shantz experiments with different ways of adding new piles to the existing bridge piers, thus increasing the piers' resistance to lateral loads. After generating nonlinear functions to represent the soil's resistances to deformation, Shantz uses Mathematica's LinearSolve command in an iterative procedure to calculate the deflection and stresses of a laterally loaded pile embedded in soil.

Shantz chose Mathematica over other systems because it gives him more control over how the analysis is performed. "Too often engineering software becomes a black box. I like to know exactly how my problem is being solved and I want control over the solution's underlying assumptions and approximations," Shantz explains.

Key features of Mathematica used:

• Symbolic
• Programming
• Graphic--animation