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Institution Forums > General > Re: Vierendeel Truss Deflection View modes: 
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Micheal Fenton - 05/02/2013 12:23:12
   
Re: Vierendeel Truss Deflection
Hi,

I am preparing for the IStructE exam in April and I would really like to find a reasonable hand calculation method to determine the deflection of a vierendeel truss. Even a method for constant stiffness members would be a help. I have found a fairly good paper called "Practical Calculation Formulae of Parallel Chord Vierendeel Truss..." which gives reasonable results for bending and axial force (i.e. when compared to structural analysis software) but for some reason the deflection does not match my results - on the other hand maybe I am misinterpreting the formulae given for deflection??

Any help would be really appreciated.

Micheal.

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W.L Squared - 05/02/2013 19:47:55
   
RE:Re: Vierendeel Truss Deflection
You can calculate the I value of a standard truss using Ad^2/2 and calculate deflection as normal.

This however does not apply to Vierendeel girders. So when I was prepraring for the exam I did this check numerous times for different loading types (as if it were a standard truss) and calculated more accurate deflections for the vierendeel on a software package (not during the exam!). This gave me a good idea of a suitable multiplication factor which I could quickly apply in the exam.

So for the exam you can do the standard check and multiply your answer by say 10 or 12 (depending on your research)... This at least lets the examiner know that you're aware that a vierendeel will deflect more than an ordinary truss. That's what they're looking for - not precise answers down to the mm!

I advise you to stay away from vierendeel girders in your "preferred scheme" for part 2. My advice - K.I.S.S - Keep It Simple, Stupid! :-)

Hope that helps.

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Micheal Fenton - 06/02/2013 09:15:45
   
RE:Re: Vierendeel Truss Deflection
Hi WL Squared,

Thanks for your response and the advise - I thought I would need to do something like that alright.

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Steven Frew - 07/02/2013 07:54:13
   
RE:Re: Vierendeel Truss Deflection
I agree with W.L.

WL^2 / 8 all the way in the exam.

I attempted a wind moment frame in my exam and it all very nearly ended in disaster! Too much analysis time required.

I think the exminer must have taken pity on me!

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Craig M - 07/02/2013 12:41:57
   
RE:Re: Vierendeel Truss Deflection
Do you have an email address and I will send you some info

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Micheal Fenton - 07/02/2013 22:23:47
   
RE:Re: Vierendeel Truss Deflection
Thanks to all who responded.

Hi Craig M, my email address is haulief@gmail.com. Anything you have for this (or any other exam prep material) would be really appreciated. I am currently living in Sydney and there are no exam prep courses.



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Olanrewaju Okunola - 05/09/2018 16:57:59
   
RE:Re: Vierendeel Truss Deflection
hello Micheal,

i saw your details and your discussion on Istructe website regarding Vierendeel Truss. Please can you send me any information that you have on this please to ookunola@gmail.com. many thanks

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Anthony Winn - 03/01/2018 09:04:52
   
RE:Re: Vierendeel Truss Deflection
Hi Craig,

I trust you are well. 

I saw this post from a few years back.

Can you give me any tips on quick Vierendeel Truss design.  I take it wl^2/8 is ok for deflection for the exam?

Reagrds,
Tony
tonywinn11@gmail.com

...

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Nabil Attari - 03/01/2018 12:01:19
   
RE:Re: Vierendeel Truss Deflection
Hi Craig,

I'm preparing for the CEng exam as well,
​your help is highly appreciated.

Nabil,
engnsha@hotmail.com

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Debbie Soyemi - 26/04/2018 17:03:47
   
RE:Re: Vierendeel Truss Deflection
Hi Craig, 

I am also preparing for the IStructE exam, can you please send any info you have on vierendeel truss design and any exam prep material if possible. 

Kind Regards, 

Debbie 
debbie.soyemi@gmail.com

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