I have a fixed-end fixed-end beam with two roller supports as well and a load applied in the center of the beam, as shown below.(adsbygoogle = window.adsbygoogle || []).push({});

I've chosen my redundant forces to be the force at B (point up), the force at C (pointing up), the force at D (pointing up) and the moment at D (counter-clockwise).

I'm solving for these reactions using deflection and slope equations for a cantilever beam; specifically:

The sum of all the redundant force and the applied load will produce a net deflection at B=0

The sum of all the redundant force and the applied load will produce a net deflection at C=0

The sum of all the redundant force and the applied load will produce a net deflection at D=0

The sum of all the redundant force and the applied load will produce a net slope at D=0

using these equations: http://www.advancepipeliner.com/Resources/Others/Beams/Beam_Deflection_Formulae.pdf

I wrote up a worksheet in MathCAD and used matrix inversion to solve for the redundant forces. However, I am highly suspicious of the answers because the reactionary forces at B and C are not the same (as I'd assume they would be due to symmetry). Here is my worksheet:

Anyone see any errors that I have made?

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Statically Indeterminate Beam

**Physics Forums | Science Articles, Homework Help, Discussion**