Child-Friendly Column Base Connection
Child-Friendly Column Base Connection
(OP)
I have an unusual situation where I have to connect a steel structure to the lid of an existing CIP concrete sistern, and the column base connection needs to be "child-friendly".
I am using tube columns (friendly), but the column base will be exposed. I have tried to look at expansion anchors that would have a countersunk head, such as a Phillips flat head, but they only come in 3/8" maximum diameter, and that seems pretty small for a structural column. I have TS7x7 columns, and the maximum uplift load is 10.8 kips, with 2.7 kips of base shear.
Does anybody know of a larger diameter fastener available with a countersunk head, or is there another way of skinning the cat? Also, it would be nice not to have to use four bolts, because the columns are very close to the edge of the lid, and edge distances become an issue.
I am using tube columns (friendly), but the column base will be exposed. I have tried to look at expansion anchors that would have a countersunk head, such as a Phillips flat head, but they only come in 3/8" maximum diameter, and that seems pretty small for a structural column. I have TS7x7 columns, and the maximum uplift load is 10.8 kips, with 2.7 kips of base shear.
Does anybody know of a larger diameter fastener available with a countersunk head, or is there another way of skinning the cat? Also, it would be nice not to have to use four bolts, because the columns are very close to the edge of the lid, and edge distances become an issue.






RE: Child-Friendly Column Base Connection
As a side note I know they are available in fairly large sizes as well, since I have used them on architecturally sensitive features like single stringer stairs and exposed interior steelwork.
Cheers,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...
RE: Child-Friendly Column Base Connection
Put a circular concrete encasement over the first 3-4' of the column?
Some kind of sheet metal cap like we see on light pole foundations, except without sharp corners?
RE: Child-Friendly Column Base Connection
RE: Child-Friendly Column Base Connection
RE: Child-Friendly Column Base Connection
Mike McCann
MMC Engineering
RE: Child-Friendly Column Base Connection
There are two problems with field welding. First, since the structure is outdoors, everything is hot-dip galvanized. Second, this job is in St Johns, US Virgin Islands, and I don't know what the field welding capabilities are, but welding galvanized steel is not good.
I wish I could simply encase the base plate some how, but the columns are very close to the outside wall of the cistern, making it physically impossible to use a round encasement.
Not sure I understand PackerFan's idea. What do you mean by "type of screw"? If I had a 7x7 base plate with holes in it and internal nuts, you could screw in allthread rods, and lower into epoxy grouted holes. However, the column wouldn't be too stable under construction (OSHA req'mts).
RE: Child-Friendly Column Base Connection
This is not a job for engineers, just one requiring common sense. There's nothing child-friendly about concrete, last time I checked...
Or, you could Google playground supplies and hardware - you'd be amazed how many products are out there.
tg
RE: Child-Friendly Column Base Connection
RE: Child-Friendly Column Base Connection
Hopefully you're not in US, or if you are, hopefully the Kwik Bolt II comes in a similar flush-headed version.
Cheers,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...