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# Re: Which method do you like for calculating deflection

• To: seaint-seaosc(--nospam--at)mail-list.com
• Subject: Re: Which method do you like for calculating deflection
• From: nma <nma(--nospam--at)nma-se.com>
• Date: Mon, 11 Mar 2013 08:02:47 -0700
• List-subscribe: <mailto:SEAINT-SEAOSC-on@mail-list.com>

I have not used your methods since I graduated from school in 1960. Today I just dump something like that into RISA. But the first things I do look at in the output is the deflections.
```
Neil Moore, PE, SE

On 3/11/2013 7:40 AM, Lloyd Pack wrote:
```
```Hello List,

I'm wondering which method is your preference for calculating deflections
on two or more continuous unequal spans.  We have equations for equal
spans but not for unequal spans.

On two span continuous beams, I've used superposition to calculate the
middle reaction then summation of moments about the left reaction to
```
get the right reaction. Then I use summation of vertical forces to get the left reaction, followed by calculating the shears at each side of the reactions, then the moments from the area of the shear diagrams. I usually then use the moments and back calculate a uniform load and then use that uniform load in the deflection equation for a simple span beam.
```
```
I'm not loving this method. I've been wondering about using a moment- area method or an M/EI approach. If any of you use either of these I would really like to hear your approach. If any of you use something else, will you tell me what you like and why? I would like a more elegant and hopefully more precise method.
```
```
```
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