Grout hole requirement 2

[am]

We generally provide 14mmØ grout hole in a base plate when the base plate size gets bigger than 300mm. To my understanding, this comes from accepted industry practice. I am wondering, if there is any published document where I can find the proper recommendation on grout hole size and the number of grout holes as a function of base plate size?

Thank you all in advance for your kind assistance.

Regards

AM

 

[dbuzz]

On four-hole base plates, which cover most UBs and UCs, I've usually just seen just two holes, one each side of the column web.
+ +
o o
+ +

(where "+" is a bolt hole and "o" is a grout egress hole)

On "longer" baseplates, say for WB's, I've seen grout holes located between bolts on both side of the column web.
+ +
o o
+ +
o o
+ +
o o
+ +

 

[am]

dbuzz

Thank you very much for your input. We do exactly the same thing as you explained. I am looking for any technical reference to justify this approach.

Regards

AM

 

[14159]

Because you're using mm, I assume you're somewhere besides the USA.

300 mm = 11.8-in., which is a very small base plate. Everybody I know starts to use a grout hole for base plates above 24-in., or about 600 mm.

According to the AISC Manual, there's only need for one grout hole.

DBD

 

[dbuzz]

I don't know of any references that address this. It's more of a construction issue, ensuring that the grout spreads underneath the base plate.

 

[dbuzz]

DBDavis, where I work it's usual practice to include grout egress holes once the base plate width exceeds 300mm.

 

[am]

Thank you all for your responses. It is interesting to know about the practice in the USA also. We will stick with the running practice of 300mm then.

 

[14159]

I'm in the US and I can tell you that I've probably designed a 4-digit number of base plates on jobs between 18" (450mm) and 22" (560mm) square without grout holes. As far as I know that's typical in the US. I've worked for three different firms that used 24" (610mm) as the cutoff for inclusion of grout holes.

The 300 mm (12") limit seems ridiculous to me. Are you sure you've not misunderstood that or been told wrong?

What do you do if you have an 8" (200mm) square tube column? You'd have a base plate larger than 300 mm under that to have any chance at anchor rod clearance. Do you put a grout hole in the middle of the tube and make sure that there's a hole somewhere for air to vent?

For that matter, I've never even seen a base plate smaller than 12" (300mm) except for very small posts in mechanical frames and steel stairs. We even use a 12" (300mm) base plate under 4" (100mm) tube columns which is about the smallest tube column I've ever used except for about twice when I had to use 3" to cram it into a stud wall.

I'll be anxious to know what others use.

DBD

 

[am]

DBD

Thank you for your comments. Personally I do not have any satisfactory input in this subject. I will run this discussion with my other industry colleagues/peers and will update on this subject if I get any feedback.

Regards

 

[14159]

My big question is: How do you ever have base plates smaller than 300 mm?

Please let us know the results your discussions with your industry colleagues. It is interesting to know the opinions of others.

Have a good day (or not in this case, I suppose).

DBD

 

[dbuzz]

There's more than one way to skin a cat DBD.

My answer to your "big question":

The standards for my company (a world-wide engineering and project services group) and several clients (including some of the world's major resource companies) have the following Australian sections where the base plate width does not exceed 300mm:
- 150UB, 180UB, 200UB, 250UB, 310UB, 360UB, 410UB, 460UB, 530UB, 610UB
- 100UC, 250UC
- 100PFC, 125PFC, 150PFC, 180PFC, 200PFC, 230PFC, 250PFC
- 65SHS, 75SHS, 89SHS, 100SHS, 125SHS
- 76CHS, 89CHS, 102CHS, 114CHS, 140CHS
- 65EA, 75EA, 90EA, 100EA, 125EA, 150EA, 200EA

 

[14159]

dbuzz, I don't have any idea what those sizes are!

In the US, everybody I know (any other US engineers are welcome to join in any time - I'm currently outnumbered?!) puts 4 anchor rods per base plate minimum except for very small posts. These four rods go at the corners of the base plate with the base plate size selected to allow the rods to clear the flanges. For example, one of the most common arrangements I've seen is a 10" I-shaped column with an 18" base plate. The US Government Agency OSHA requires 4 anchor rods minimum for most cases and it is usually difficult to get all 4 within the area between the flanges. Therefore the need for a base plate larger than 12" in practically all cases I've seen.

I'd still like to know what bad thing happened on all the hundreds of 18" and 22" base plates I've used without grout holes!

DBD

 

[dbuzz]

DBD

First, a quick lesson is section designations for this part of the world:
- UB is a 'Universal Beam', similar to your 'S' shapes
- UC is a 'Universal Column', similar to your 'W' shapes
- PFC is a 'Parallel Flange Channel'
- SHS is a 'Square Hollow Section'
- CHS is a 'Circular Hollow Section'
- EA is an 'Equal Angle'
The numerical 'prefix' is the nominal depth or diameter of the section. The UK has similar designations for their structural sections.

Like you we also use a four-bolt arrangement for base plates, however they are typically placed 'inside' the flanges, rather than at the corners. Only the smallest sections (150UB, 180UB, 200UB, 100UC, 150UC and 200UC), that can't accommodate the geometry of four bolts inside the flanges, have the bolts at the corners of the base plates.

Finally, I don't think anyone's suggesting that anything "bad" has happened to your 18" and 22" base plates. In fact, the obverse of the list in my post above is that grout egress holes are required on relatively few base plates (where the width exceeds 300mm) and generally only for 'heavy-duty' sections:
- 700WB, 800WB, 900WB, 1000WB, 1200WB (WB is a 'Welded Beam', i.e. a fabricated, rather than hot-rolled, beam shape)
- 350WC, 400WC, 450WC (WC is a 'Welded Column', i.e. a fabricated, rather than hot-rolled, column shape)
- 150UC, 200UC, 310UC

Steel detailing practice varies from country to country, perhaps even from state to state where you're from. Broadly speaking, nowhere's practice is necessarily better than anywhere else's, it's just the way they do it. You'll just have to accept that.

 

[am]

DBD

Sorry, I could not get back to you earlier. In the mean time I noted that dbuzz has given some of his input and I was going to write the similar thing.

To my understanding this forum is for sharing the vast knowledge of all the people who participate in discussions and we all mutually benefit from each others' knowledge and experience. Over the years these standards were developed based on the input received from various personnel. Construction logistics vary from one project to another due to available facilities. May be the outcome is conservative in our part of the world, but I personally do not think that they are incorrect or bad practice.

I value and respect your comments and if I noted a tone of sarcasm/cynicism [hope I am wrong] I regret that.

Kind regards. Have a good day.

AM

 

[Wopshistos]

BCSA/SCI Publication 207/95 section 6.6.

Baseplates of 700mm x700mm or larger should have holes. Additional holes provided for each 0.5m sq.

Hope this is what you need.


(DBD - 27" x27" !! You're probably safe!)

 

[am]

Wopshistos

Thank you very much. This is a valuable documentation.

Regards

AM

 

[14159]

am typed: "...I value and respect your comments and if I noted a tone of sarcasm/cynicism [hope I am wrong] I regret that."

I am sincerely sorry for adding negativity to the thread. My wording was careless and I'll be more careful in future posts.

Have a good day.

DBD

 

[am]

Thanks DBD, no ill feelings. Cheers

AM