n8structural
Structural
- Dec 6, 2010
- 8
We provide engineering services for a stair and railing manufacturer in the Midwest. Typically railings are welded to the top of stringers or in some cases welded to a baseplate that is anchored down. However one common detail in the railing industry is to core a hole into concrete and grout the railing post in place with a high-strength non-shrink grout. This is a standard practice and I see this all the time. For instance a 2" post (square or round) is grouted in a 3" diameter core some dimension (3"-4").
My question to you is how would one go about proving this base connection meets the ASCE load requirements of 50 plf or 200# in any direction? Typically a 43" high railing with a 4'-0" post spacing would have a base moment of 8.6 kip-in. How do I provide evidence that this detail is sufficient. NAAMMM shows this type of condition but does not address how it is designed (from what I can find).
My concern is not with the design of the post itself, but rather with the connection of the post to the concrete. Would this be a modified example of an anchor and therefor could be designed for concrete breakout strength per ACI 318 Appendix D? A common product I see specified is Por-Rok (a high strength non-shrink anchoring grout). Obviously this does not work with an aluminum post, as embedding aluminum in concrete is not a good idea.
Any insight or ideas would be appreciated.
N8structural
My question to you is how would one go about proving this base connection meets the ASCE load requirements of 50 plf or 200# in any direction? Typically a 43" high railing with a 4'-0" post spacing would have a base moment of 8.6 kip-in. How do I provide evidence that this detail is sufficient. NAAMMM shows this type of condition but does not address how it is designed (from what I can find).
My concern is not with the design of the post itself, but rather with the connection of the post to the concrete. Would this be a modified example of an anchor and therefor could be designed for concrete breakout strength per ACI 318 Appendix D? A common product I see specified is Por-Rok (a high strength non-shrink anchoring grout). Obviously this does not work with an aluminum post, as embedding aluminum in concrete is not a good idea.
Any insight or ideas would be appreciated.
N8structural