What is the best way to reduce the weight of a steel beam without compromising its strength?

[danielgomez]

Hi everyone,
I’m working on a project where we need to reduce the weight of a steel beam, but we can’t sacrifice its strength. What are some effective methods or design considerations to achieve this balance? Any suggestions or tips would be really helpful!

 

[W460x68]

Speaking purely to the weight of material, going with a deeper section is the best way to economize a steel beam. You'll get more strength for less weight.

 

[DrZoidberWoop]

but we can’t sacrifice its strength

What kind of strength? Global flexure? Shear? Ability to handle concentrated loads/bearing? Serviceability concerns?

Obviously castellating a beam saves weight, but has limits.

 

[KootK]

I was also going to recommend castellating. It does reduce shear capacity but that's rarely what governs the design of a steel beam.

But, yeah, knowing what kind of strength is massively important here.

As an example, if your governing failure mode is lateral torsional buckling in flexure, you may be able to save gobs of weight by adding in small elements to the system that laterally brace your beam compression flange.

 

[Eng16080]

Definitely agree with the comments above concerning what strength. Reducing the weight of the beam will most certainly compromise something, it's just a matter of whether that something controls.

Assuming the beam strength in strong axis bending/deflection controls and assuming it's fully laterally braced, then making the beam deeper is usually the solution. Castellating the beam is something that was more common (I want to say in the 60s/70s) but is less common now due to the labor involved. Most clients will not directly care about beam weight, but rather cost, so if the deeper/lighter beam is not cheaper, it probably fails to meet the overall goal.

 

[SWComposites]

yes,
a) why do you need to reduce the weight?
b) what strength checks are currently sizing the beam?