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toha_mh
Posts: 15
Registered: ‎06-30-2012
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Beam Moment Capacity Problem

547 Views, 3 Replies
10-07-2012 02:23 AM

Hi everybody,

 

Here is an attachment file of a simple structure. The spans are 8*8 on an average. I gave the beam dimensions 40*80. When I check for required reinforcement, it comes all ok. But when I go to provided reinforcement for beams (for example beam no. 35 to 38), in the beam diagram it shows that the moment capacity is less than the distributed moment (usually in the supports, negative moments).

 

How to solve this problem? I tried to increase the sections manually. But it needs very large sections. It increases the capacity, but at the same time it also increases moment distributuons. So it needs a huge sections, which seems not right. And am I supposed to do this manually by trial and error method? Isn't there any easy solution?

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Artur.Kosakowski
Posts: 5,115
Registered: ‎12-17-2010

Re: Beam Moment Capacity Problem

10-08-2012 12:22 AM in reply to: toha_mh

Try to use the options indicated on the attached picture. Imn addition check if you have teh right concreet grade assigned to the beam. You may also want to consider calcuklating this beam as the T shape one.

 

http://forums.autodesk.com/t5/Autodesk-Robot-Structural/Beam-offsets/m-p/3332921/

 

http://forums.autodesk.com/t5/Autodesk-Robot-Structural/T-slab/m-p/3185418

 

 



Artur Kosakowski
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Contributor
toha_mh
Posts: 15
Registered: ‎06-30-2012

Re: Beam Moment Capacity Problem

10-10-2012 02:03 AM in reply to: Artur.Kosakowski

Hi thanks, it works!

 

I found something more, what I am not sure about. There is an option called Typical Reinfocement. What is the use of it?

 

I tried to increase bar diameter for shear rein from here. As a result it increases the capacity, but instead of replacing the old transverse bars (suppose from 84 Ø 10 to 84 Ø 13) it adds more transverse bars with new diameter. (For example before it was 84 Ø 10, after change diameter from 10 to 12, now it is 80 Ø 10 + 80 Ø13). So the spacing also decreases.

 

 

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Artur.Kosakowski
Posts: 5,115
Registered: ‎12-17-2010

Re: Beam Moment Capacity Problem

10-10-2012 02:15 AM in reply to: toha_mh

This is intended for creating manual bar distribution in the beam. It generates rebars based on the parameters you entered. Then you can run verification of such created reinforcement vs. loads you applied. Usually you use his option not having any rebars in the beam :smileyhappy:



Artur Kosakowski
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