It has been a few years since I have done beam analysis, and I really don’t remember how to solve this type of problem so I have been reading up on it. I have found similar situations but nothing that matches the problem I am having.(adsbygoogle = window.adsbygoogle || []).push({});

I have a continuous beam of 3 spans with a uniform distributed load centered in the middle span (not full width).

I believe I need to use theEquation of Three Momentsto solve this with Matrices, but I am stuck.

Since my material and cross sections are the same for the beam, I believe my 3-moment equations reduce to:

(M1*La) + (2*M2*(La+Lb)) + (M3*Lb) = - (6*xa*Aa)/(La) - (6*xb*Ab)/(Lb)

(M2*Lb) + (2*M3*(Lb+Lc)) + (M4*Lc) = - (6*xb*Ab)/(Lb) - (6*xc*Ac)/(Lc)

How do I getxa, xb, xc,andAa, Ab, Ac? I understand these to be the centroids and areas of the moment curves for each span, but I am really struggling to come up with their values.

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# Need help with 3-moment equation (multi-span beams)

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