I have a structure that can have 3 or more supports. It will carry an evenly distributed load with overhang. I thought I would tackle 3 supports first and solve with superposition but am getting the center support reaction to be very low and will go negative as I move the outside supports more outboard. I calculated the center deflection without the center support first then set that equal to the center deflection with the center support being the only point load. Then took those results back to the original FBD to find the outside support. What am I doing wrong?