MDX Software - FAQ #13<BR><BR>

Why are the deflections across the system not the same when 
I use the condition AVERAGE LIVE DEFLECTIONS?<BR>
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<UL>Because each tabulated deflection across the system is the max that would 
  occur at that location for the separate transits of live loading in the 
  particular lanes causing those max deflections. When this condition is used, 
  influence surfaces for deflections are developed to reflect the intent of 
  AASHTO for equal sharing of resistance to deflections across the system. For 
  example, when a unit load is applied at a particular tenth point, the 
  deflection is max at that location and tails off across the system with 
  distance from that point. At that time those deflections across the system at 
  that tenth point are averaged, producing for that location a deflection 
  influence surface which is level along corresponding tenth points. Live 
  deflectons are determined by the location of lanes, and trucks within those 
  lanes, when using those influence surfaces for determining max deflections. 
  The net effect typically will lessen the higher deflections, and increase the 
  lower deflections which would occur if the condition were not 
used.<BR><BR></UL>