What size I beam should i use?

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In summary, the conversation discusses designing a roof with specific dimensions and weight requirements. The question of what dimensions to use for the I-beams is posed, but more information is needed about the project before a proper solution can be determined. It is suggested to seek professional help, as structural design is a complex and important task.
  • #1
escobar147
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I am designing a roof which is 5 metres wide and 10 metres long. the total weight it has to support is 20,000 kg.

there will be two I beams spanning the 5 metre width, each i beam is 3.33m apart.

what dimensions should i use for my i beam?

any help would be massively appreciated, is there an industry standard beam for this type of project?
 
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  • #2
Need more info.

I'm not quite sure the application or if this is just a problem from your homework.

But there is a lot that goes into structural design and we need more information about what you're setting it on and your perimeter structure. Is it sitting on masonry wall? what kind? is it going to be secured mid span to a girder? Is the roof pitched? What is the other structural information? Most likely for things like this, you would have a square steel (i-beam) frame around the perimeter and use metal joists to span the short distance at approximately 1.5m-2m on center. If its allowed by your local code, you may also wind up using wood trusses & girders. You get the joist size, by taking the length of the longest unbraced portion of the beam, its dead and live loads for the area its supporting, and the load it has to support. You have to account for wind loads, uplift forces and resistances and how much beams/joists are allowed to deflect.

Normally, you would have to get this work permitted and have the stamped of a licensed structural engineer for it. Could you give some more information?
 
  • #3
Assuming this is a real project, stop what you are doing and contact a local civil/structural professional engineer. You are out of your element. Do not put people in danger due to your ignorance.

If this is a homework problem, please state so. I think there is a different forum for that.
 
  • #4
agreed

/Agreed. Structural steel is not a Do It Yourself home project.
 
  • #5
Good advice. Thread closed.
 

Related to What size I beam should i use?

1. What factors should be considered when determining the size of an I beam?

The size of an I beam should be determined based on the load it will be supporting, the span or distance it needs to cover, and the type of material being used. Other factors to consider include the desired safety factor, the type of connections being used, and any potential deflection or bending that could occur.

2. How do I calculate the load that an I beam can support?

The load that an I beam can support is determined using the beam's moment of inertia, which takes into account the dimensions and shape of the beam. The formula for calculating moment of inertia is I = (b*h^3)/12, where b is the width of the beam and h is the height. The maximum load that the beam can support is then calculated using the beam's maximum bending stress, which is determined by the type of material being used.

3. What is the difference between a wide flange beam and an I beam?

Wide flange beams and I beams are both types of steel beams that are commonly used in construction. The main difference between them is the shape of the cross-section. I beams have a narrower, taller profile, while wide flange beams have a wider, shorter profile. Wide flange beams are typically used for heavier loads and longer spans, while I beams are more commonly used for lighter loads and shorter spans.

4. How do I determine the appropriate safety factor for an I beam?

The safety factor for an I beam should be determined based on the type of load it will be supporting and the level of risk associated with the structure. For most construction projects, a safety factor of 1.5 to 2.5 is recommended, meaning that the beam should be able to support 1.5 to 2.5 times the maximum expected load.

5. Can I use multiple smaller I beams instead of one larger one?

In some cases, using multiple smaller I beams can be a viable alternative to using one larger beam. This approach can distribute the load more evenly and reduce the risk of deflection or bending. However, it is important to consult with a structural engineer to determine the most appropriate size and spacing for the beams in order to ensure the structural integrity of the building.

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