Inputting shear diagram to RAPT 1

[Datpt]

Hi everyone,
Currently, I am using RAPT for designing beams and slabs.

When inputting span moment diagrams, I have noticed that RAPT automatically calculates corresponding shear diagrams.

However, I have observed that the sign of shear forces is provided in a reversed manner, as indicated in the attached scan.

Personally, I don't think RAPT is wrong but currently, but currently, I cannot explain this calculation.

Has anyone met the same situation?

 

[rapt]

I will have to check.

But why wouldn't you contact RAPT support. We do not run our support through online forums like this!

 

[Datpt]

To Rapt
I sent an email to the address "support@raptsoftware.com", asking this question on the 29th of September but there has been no reply since then.

 

[rapt]

I will check to see what happened. Someone else is handling support now.

 

[BAretired]

Looks to me like the moment should be positive (tension on bottom). Shear is normally considered positive between left support and midspan.

 

[Datpt]

To Rapt.
Thank you so much. I deeply apriciate this!

 

[BAretired]

Load is negative when acting downward. Reactions are positive when acting upward. Shear starts with the left reaction and is positive just inside the left support. It decreases as x increases, becoming zero at or near midspan, goes negative and eventually increases to zero after the right reaction.

 

[hokie66]

There are some who use a different sign convention. If you show positive moments above the line, that turns everything upside down. Consistency is key.