huangyhg

sleeves for embedded railing posts
our handrail & railings spec indicates that the when railing posts are to be anchored into the stair concrete itself, that posts are to be anchored with core-drilled holes or pre-set sleeves of diameter at least 3/4" more than the diameter of the post being anchored, not less than 5" deep. fill space around post with non-shrink, non-metallic grout or anchoring cement."
my questions is that i would usually specify steel sleeves at this location but the contractor has pvc sleeves on site. are there any concerns with the bonding of the grout to the pvc sleeve or the pvc sleeve to the base concrete that i should be aware of?
i would actually be concerned with the pvc crushing under load. the bearing forces can become significant with this detail - the 0.7k-ft moment (200#*3.5') is getting resisted over the 5" embed you're providing. i've never looked into an allowable bearing pressure for pvc, but that's something i would definitely check into.
the pvc will not bond to the grout in the same way that steel would. pull the sleeves out and bond grout to concrete.
i agree with seit...could be a crushing/deformation issue with the pvc as well.
good point, ron. come to think of it, when i did draw this detail, the contractor preferred to core the holes after the fact (and not provide a sleeve), because he said the sleeves have a habit of not ending up where you need them anyway. we had them core holes after the fact and fill with the non-shrink grout you mentioned.
be careful with the grout. i recently investigated a case where the grout expanded enough to crack the surrounding concrete. seems the contractor's choice was a rapid-setting grout containing gypsum, which was poured short of the top and finished later with a different grout that was a better color match to the concrete.

ralph
structures consulting
northeast usa

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