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analyse of multi bays braced frame

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ap3120

Student
Joined
Jun 22, 2021
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GB
I'd like to get the axial forces in a pinned supported 3 bays braced frame. The frame height is h=8m and the width of one bay is L=7 m.
frame_vi7lwz.png

There is only one point load of 1 kN applied on the top left corner.
I'm trying to get the reactions at the supports, but I don't know how to do that. I've also modelled the frame on SAP2000, and I don't quite understand the results (see image here):
frame2_ijoiwa.png

The horizontal reactions make sense cause the sum is equal to the applied loading : -0.69+0.4+0.25+1.03 = 0.99 kN.
However, if I take the moment about the first support on the left for example, I get:
1*h-10.85*L-10.76*2L-6.88*3L = -363.07 kNm different from zero.
So I must be missing something here, and I'd really like to understand how to solve this by hand.

Thanks for your help.
 
Thank you very much BA, it's clear now. This is the forces I obtain, it looks very nice!
20210627_233535_itvprj.jpg
 
You are welcome, ap 3120. Glad I was able to help in your understanding.

Just one further comment. It is always a good practice, after completing a complicated calculation, to sum the horizontal and vertical reactions and ensure they satisfy equilibrium, because it is easy to make an error along the way. When I checked your vertical reactions, at first I thought you were off by 300N, but I eventually realized I was reading your second reaction as 462.22 whereas you intended 162.22.

Cheers.

BA
 
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