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StructuralEng, Consultant
Category: Structural Engineering
Satisfied Customers: 7630
Experience:  Structural Engineer
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all I have a question regarding hollow structural sections.

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Hi all I have a question regarding hollow structural sections. I have a hollow structural section that is 4" by 4" if I can remember correctly. And it's a structure in a square shape with four verticle posts, eight horizontal posts Joining the vertical posts together two on each side. Then cross posts to join horizontal posts together. Total load is three tonnes. And I have a few enclosures to fix to the horizontal posts. On four of the horizontal posts I would like to drill eight 6mm holes on each and two 6mm holes on another horizontal post. Then tap the holes to fix my boxes. My question is would I be able to drill the hollow structural section and after I have drilled all holes will it still be in a safe condition? Would this affect the Integrity of the structure? Answers will be much appreciated thanks
StructuralEng :


StructuralEng :

How are you doing? I'll be happy to assist you

StructuralEng :

Do you have any sketches or pictures that I can see?

Customer: Hi sorry I can't seem to get my photo unloaded will try my best to describe what it's like. It's a square box section 3 meters x 3 meters with 4 main 4" HHS posts they are spread three meters apart from each other and are 5 meters high. To join the 4 posts together there is 8 4" HHS In total. Two on each side of the square.One is welded at the bottom of the structure horizontal and the other welded 1/4 of the way up horizontal. This makes the structure a square shape with 4x 4" HHS posts being joined together by 8x 4" HHS beams 2 on each side. Then to join the two horizontal beams together there are cross sections in between the bottom horizontal and the other horizontal 1/4 of the way up. Two of them on each side of the square so a total of 8x 4" HHS welded to the horizontals. This is the completed structure with a bucket which could take waste items of up to 3 tonne fitted on top of this. I hope this helps. What I want to do is drill 8x 4mm holes on one of the horizontal pieces at 1/4 of the way up and 8x 4mm holes on the bottom horizontal aswell. This will be happening on two sides of the structure. The holes will be 80mm apart and will be done at one corner of the square structure. Hope this makes sense. Would this cause affect to the structure drilling a total of 20 holes at 4mm sized holes. Would this be a problem in the future?
Customer: Hi have you had a chance to look at my question? Or are you still needing time?
Customer: Hi have you had a chance to look at my question. Are you able to answer it please?
Customer: Hi have you had a chance to look at my question? Can you answer it please? Thanks
Customer: I have not got an answer yet to my question that is why I haven't rated yet as no answer ?
StructuralEng :

I apologize for that long delay.

StructuralEng :

I was locked out of the question for several days. It was frustrating to me because I could see you responding, but I was unable to post

StructuralEng :

4 mm holes in 4" square tubes will not have an appreciable impact on the tensile strength of the members

StructuralEng :

It does present a way for water to get inside the member and sit and corrode it

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