FAQ #22<BR><BR>

I have multispan symmetric geometry and loading, yet the design which is
     generated has unsymmetric flanges.  Shouldn't they be symmetric?<br>
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<br> 


This may happen because there are an infinite number of solutions possible 
      for this highly nonlinear optimization problem.  The design objective used
      is minimum weight, and, for example, a 20 x 1 flange has the same weight
      as a 16 x 1.25, or a 10 x 2, 5 x 4, 14.2 x 1.408, 
      and the infinite combinations in between.  
<BR><BR>
      Each positive moment region is solved as an optimization problem separate 
      from each negative moment region, and the solutions for, say, symmetrically 
      placed positive moment regions may, because of precision, proceed toward 
      convergence along slightly different paths leading to equivalent but different 
      solutions.  Convergence even may proceed toward a suboptimal optimum, but this 
      is the best one can hope for in highly nonlinear mathematical problems.   
      (See Help/contents/computational methods/girder design generator.)
<BR><BR>
      Occasionally symmetry will be produced where it is expected, but if not, 
      it easily can be established by the user making the necessary modifications 
      in rate mode.