Area load vs girder reaction

[gasma1975]

Hi,

I have a square concrete floor 5'x5' on a 3D steel frame. Under that floor I have a steel girder supporting it. I'm trying to find the reaction in that girder. But when I run the simulation I get nothing. Its like the load is not transfered on the girder. Is their an option to tell SAP2000 that the floor has 100% contact with the girder?

Thx,

Adi

 

[notman]

The floor and the girder must have common joints in the span.

 

[gasma1975]

Hi,

When you display it extruded (3D) I see the girder inside the concrete floor. It should be under the concrete floor. The girder is supporting it.

What do you mean by common joints to span ? Where do you define it ?

Do you have an example ? send file to gasma1975@hotmail.com

thank you for helping.

Adi,

 

[notman]

Select the girder, then go to Assign --> Frame --> Insertion point, there you can choose for example the option 8 - "top center".
About the common joints. You can divide both the girder and the slab in several parts along the span. For example: select girder --> Edit --> Divide frame --> choose to divide it to 4 parts with last/first part ratio 1. Then mesh the slab to 4 in both the x and y axes. Maybe tomorrow I will send you some example if you tell me which version of SAP2000 you use.

 

[gasma1975]

Hi,

I tried your method, but still I don't get any Axial forces in the girder.

If you have the time send me your file. gasma1975@hotmail.com I'm using SAP2000 V10

if you want I can send you my model...

thx for helping

Adi,

 

[notman]

aat@gbg.bg

 

[stressed]

In order to transfer load from shell to girder, the shell must be meshed/divided at each girder. Have you done that? If not, you can select slabs and girders, then use the Edit menu to divide areas by selected lines.

Next, you can assign area loads using "Uniform to Frame" and keep default one-way load assignment if that is what you want, which should transfer area loads as distributed load along your girders. If you want two-way tranfer, just assign area load as uniform shell, which transfers area loads to joint locations only, no load transfer as distributed load along the length of your girders.

notman's suggestions to use Insertion point is useful only if you don't want to connect at centerlines, which in a deep slab system, is often a good idea. But before using insertion point, make sure you have meshed/divided your model correctly.