Flexure-Shear Interaction Model

[AndreVieira]

Hello,

I am trying to apply the flexure-shear interaction model but I am getting confused with the example provided. I have two questions:

1)
When building the section in the planar local coordinate system (y,z) it is given the following example.

section FiberInt 2 –NStrip 1 6.5 1 2.0 1 6.5 {
fiber -25.55 0 15.6 2
fiber -25.55 0 1.24 1003
fiber 0 0 35.6 2
fiber 0 0 0.84 1003
fiber +25.55 0 15.6 2
fiber +25.55 0 1.24 1003
Hfiber 0 0 0.0718 1005
}

In the first and last strips, if the thickness is 6.5 and the area is 15.6 , consequently the high will be 2.4, am I right?
Following the same idea, in the second strip, if the thickness is 2 and the area is 35.6, it means the high will be 17.2.

The location of each material is given related to the center of the cross section, so I could assume 25.55 would lead me to the center of the first strip. However 17.2/2 + 2.4/2 = 9.8, which is not 25.55.

About this, my question is, what I am understanding wrongly?



2)
About the Hfiber. Is this the stirrup? I didn't get the idea correctly I guess. If it is the stirrup, should I consider that the area provided, 0.0718, is two times the area of a rebar? If yes, I didn't find any diameter which match with this value. For example:

0.0718=2*pi()*d²/4, what gives me d = 0.21 cm.




Any help is welcome.

Best,
André Vieira

[selimgunay]

Below are the descriptions provided

section FiberInt $secTag -NStrip $nStrip1 $thick1 $nStrip2 $thick2 $nStrip3 $thick3 {
fiber...
Hfiber ...
...
}

$sectTag unique tag among FiberSections
$thick1 section thickness 1.
$nStrip1' number of strips with thickness $thick1. Considers first $nStrip1 strips in the fiber section with thickness $thick1.
$thick2 section thickness 2.
$nStrip2' number of strips with thickness $thick2. Considers next $nStrip2 strips in the fiber section with thickness $thick2.
$thick3 section thickness 3.
$nStrip3' umber of strips with thickness $thick3. Considers last $nStrip3 strips in the fiber section with thickness $thick3. Total number of strips has to match the fiber section defined.
fiber... command to generate concrete and vertical steel fibers.
Hfiber... command to generate horizontal steel fibers (stirrups)

[AndreVieira]

Thank you selimgunay,

However, I do not understand yet the example provided. What is 25.55? Are my assumptions correct? And the area of steel provided in Hfiber command corresponds to which diameter?

Thanks again.

Best,
André Vieira

[AndreVieira]

Thank you selimgunay,

However, I do not understand yet the example provided. What is 25.55? Are my assumptions correct? And the area of steel provided in Hfiber command corresponds to which diameter?

Thanks again.

Best,
André Vieira

selimgunay wrote:
> Below are the descriptions provided
>
> section FiberInt $secTag -NStrip $nStrip1 $thick1 $nStrip2 $thick2 $nStrip3
> $thick3 {
> fiber...
> Hfiber ...
> ...
> }
>
> $sectTag unique tag among FiberSections
> $thick1 section thickness 1.
> $nStrip1' number of strips with thickness $thick1. Considers first
> $nStrip1 strips in the fiber section with thickness $thick1.
> $thick2 section thickness 2.
> $nStrip2' number of strips with thickness $thick2. Considers next $nStrip2
> strips in the fiber section with thickness $thick2.
> $thick3 section thickness 3.
> $nStrip3' umber of strips with thickness $thick3. Considers last $nStrip3
> strips in the fiber section with thickness $thick3. Total number of strips
> has to match the fiber section defined.
> fiber... command to generate concrete and vertical steel fibers.
> Hfiber... command to generate horizontal steel fibers (stirrups)

[AndreVieira]

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