Hot rolled Vs fabricated member

[GasProcess]

We are modifying our work shop and all the structural members are planned to be replaced. The existing columns are tapered "I" section.
- Could some one suggest if it is OK to fabricate the tapered "I" section columns of about 7 - 8 meter length at site by A-36 plates of the required thickness.

- Will this fabricated column have same properties as factory made rolled column.

- What are point of concerns during fabrication of such column

 

[JStephen]

One point of concern is that you can get a lot of distortion by making a built-up member.

 

[Ron]

GasProcess...I agree with JStephen on the distortion issue. Difficult to control.

In general, built-up members are more likely to contain defects than rolled shapes. Rolled shapes are made under controlled conditions and the result is usually quite good.

For built-up members, fabricated on site, you have much less control and the welds can contain significant anomalous conditions such as lack of fusion, lack of penetration, porosity, cracks, and others. Further, you'll have to do a lot of nondestructive testing to check the weld quality.

Having said all that, it is not out of reason to do this provided you build in some appropriate controls and compensate a bit in "overdesign".

 

[dylansdad]

A lot of pre-engineered metal buildings that I deal with that use tapered built-up sections for columns typically use 50 ksi steel.

 

[GasProcess]

Thanks guys. I think we will go for rolled sections for the lot.