Timber Beam Deflection

[Anonymous]

Supposing this structure of 4x4 columns and beams @ 10' in length is built in the field in a concrete foundation. Roboto draws these diagrams of deflection with a maximum deflection of 6.5506 for the -1kin dead load (there may be 500lb of live). My question is would this amount of deflection be visible in the beams when loaded to the eye? As well is there some metric for what 6.5505 actually means? In terms of a scale factor of 1inch that was input for the deflection diagram.

Thank You!

[Artur.Kosakowski · Accepted solution]

Hi @Anonymous

It may be easier to determine where this value is taken from when you add display of diagram descriptions. It is something like on the picture blow:

 

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[Anonymous]

I suppose Dis is short for distance or displacement in inches so I would imagine that the deflection in the middle of the beam would be less than 2 inches if one looks at the graphical scale. It was curious to me that one can zoom in and out and the structure will get bigger and smaller but the graphical scales for the diagrams do not.

I'm still in question about Max: 6.5506. Does that mean that the bar will fracture after that amount of deflection? According to the graphical scale there isn't any more than 2 +- of deflection anywhere in the bar. I could use some clarification on these issues. Thank you for your reply.

[Artur.Kosakowski · Accepted solution]

Hi @Anonymous

I suppose Dis is short for distance or displacement in inches so I would imagine that the deflection in the middle of the beam would be less than 2 inches if one looks at the graphical scale. It was curious to me that one can zoom in and out and the structure will get bigger and smaller but the graphical scales for the diagrams do not.

This distance (line) is the reference when you want to measure the displacement on the printout rather than on the graphical viewer.

I'm still in question about Max: 6.5506. Does that mean that the bar will fracture after that amount of deflection? 

At this stage (static analysis) it is just information about the displacement of a given point along a bar. If such deformation will cause any fracture is to be decided on (e.g. comparing with the allowable deflection as per selected design code). 

If one or more of these posts answered your question, please click Accept as Solution on the posts that helped you so others in the community can find them easily.

[Anonymous]

That is more deformation by a good qty over 1/240'th of a 10' span. So the load has to decrease to to a level of deformation less than 1/240'th of a span or so. Maybe it's better to add some more 4x4 posts inside. I've really liked the capabilities of the Roboto.

Thank You!