I want to analyse a steel industrial building where the structure have purlin and the wall
like metal sheet or brick.
I model the structure using frame 3d model because they also have concrete floor (storey)
between 2 column (middle two column). The beam of floor also using steel too that connected
with Wide Flange beam between 2 portal with 6 m length.
If I model with open frame, many member design are fail because they have no retraint to the
direction of wall.
I make the purlin and release them at the end of purlin member so it only take moment and

they are oke.

That I want to ask :

1. How can I model using STAAD.pro the column with wall so the member can't be fail again
but my model is 3d open frame model without adding shell element for the wall?

2. Can it also model without purlin so the rafter also in open frame but it restraint to the
direction of purlin and the member are not fail too?

3. How can I restraint of floor beam because if they have no restraint, many member are
fail?

I hope I can get helping explanation, thanks a lot.

### 5 Replies (Most Recent Reply)

• This question brings up many excellent points about modeling and setting design parameters in STAAD.Pro.  Refer to the image below:

Assume that this structure has metal wall panels that will transmit wind loads to the steel framing, but will be considered ineffective in resisting lateral loads through shear wall action.  One approach to modeling this condition would be to create Wind Definitions and Wind Load Cases, and allow STAAD.Pro to automatically generate wind loads, which will we applied to the nodes of the model.  Another approach would be to create a mesh of plates that span between the girts, assign the IGNORE STIFFNESS specification to those plates, and apply plate pressure loads to the plates to represent the wind pressures.  The IGNORE STIFFNESS specification will instruct the program to consider the plates ONLY for the purpose of distributing the wind pressures to the supporting framing, but to ignore the plates when the stiffness matrix is formed, so the plates will not provide any resistance when the model is analyzed.

Regardless of the method used to apply the wind loads, there will always be the issue of verifying/assigning the appropriate bracing parameters when it comes to design.  For example, in the model illustrated above, we might want to indicate that:

• the buckling length of the columns about their weak axis should be set to the distance between the purlins,
• the buckling length of the columns about their strong axis should be set to something approaching the full height of the column,
• the unbraced length (for bending) of the column flange that is in contact with the metal siding should be set to some value that corresponds to the spacing of the connections between the siding and the column, and
• the unbraced length (for bending) of the column flange that is toward the inside of the building should be set to some value that corresponds to the spacing of the girts (if engineering judgment dictates that the girts are effective at bracing the inside flange).

All of these design decisions are indicated by the assignment of design parameters like Ky, Ly, Kz, Lz, UNT, UNB, etc.

Regards,

Chris

• Dear Sir,

Thanks,

Rajkumar

Hi,

I  have attached a sample model.

industrl_shed.std