fixing concrete railing posts to balcony

[dand99]

I am taking on a metal railing for a concrete balcony. The widest edge is 5m long, with no side (wall) supports. (//www.diynot.com/forums/viewtopic.php?t=285380....)

Up until now I had planned to drill 200m into the concrete ledge and anchor the posts that way. A friend suggested that I anchor bolt the posts to the (outside) edge of the balcony - see sketch. Two anchor bolts per post, with 20 mm of a 1250 post in contact with the concrete.

This looks to me (initial reaction) much weaker, and not really suitable for a balcony - either because of the anchor bolts susceptible to pushing force on the balcony, or bending failure at the ledge lip, or crushing failure of the posts at the anchor bolts. Am I mistaken ? Is it worth looking into ?

Any input appreciated...

Thanks

D.

Untitled

• dand99
• 10 Aug 2011
• 1

 

[BBSBuilding]

Will the top rail be supported?

 

[Static]

Depends on what you planned for the top fixing detail.. lever arm on the side fixed will be more but you will have more balcony space and less fixing protruding inside the railing line to trip on..

Sorry but i know nothing of concrete standards set in israel so couldnt comment on suitability with the balcony concrete.. also same applies to fixing you choose..

In the end just design the fixings for the pull out forces for each case.. but chances are they will be pretty closely matched.. only thing that may scupper things would be the edge distance for the side fixed if you have a slim balcony..

 

[dand99]

I ran some figures on using sleeved anchor bolts, assuming I had 2000 psi concrete to attach to. Having only 20cm available to bolt to the wall edge gave me too big a moment (at least according to my calcs....) - I could have added some struts fixed to the inside lip, but I wasn't too happy with that.

Played it safe and drilled 20 cm down, 1-2cm space around each post and filled it with anchor grout (sika 214). Pain to drill, pain to set level in two planes - but all done now....