In RM Bridge the optimization of design parameters is done with the AddCon Method. The Additional Constraint Method is a solution for optimization problems in general within structural engineering. It is known as an extension of the Unit Load Method. 

   

The constraints could be deformations, stresses, forces, and others, and they should be applied to a defined region of elements. While the computer program will provide the best possible solution to the proposed iterative process, it is the bridge design engineer that should prepare the correct and logical constraints and criteria to be applied. 

The results are split into two parts and the sum should match the user constraints:

• constant
• variable

   

Weighting factors are used as the basic unknowns for the system of equations and the linear optimization can be extended to non-linear problems.