Distributed load with overhang and multiple supports

[gmreit]

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?

 

[PhanthomJay]

Hard to say what you are doing wrong without showing your work. With the overhang on each end the center support may likely be negative acting down on the beam, but it should be getting less negative and ultimately positive when you move the outside supports outward reducing the overhang. Your superposition method with deflection analysis should work if you are calculating deflections correctly or using tables properly.

 

[gmreit]

Thanks for the reply. I seem to be getting the opposite responce as I move the outside supports outward. I will take a picture of my work then for you to check. I wonder if my sign convention is off somewhere

 

[DrClaude]

Thanks for the reply. I seem to be getting the opposite responce as I move the outside supports outward. I will take a picture of my work then for you to check. I wonder if my sign convention is off somewhere

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