|
retaining wall frost protection
i am looking to see if there are any requirements for providing frost protection for isolated retaining walls. i can only find requirements in the ibc for foundations and footings however, i'm not sure if i would classify an isolated retaining wall as a foundation or footing.
so, does the code require me to provide frost protection for an isolated retaining wall?
if it is a rigid (poured concrete or reinforced block), the prudent thing to do it get the footing deep and have an excessive amount of drainage and backfill control.
if it is a segmental retaining wall (non-rigid), the movement can be accepted without structural or visual problems, the depth is not as important, but drainage is still a big item.
dick
my geotech used to remind me - there are three essential factors for frost heave to occur: 1. water, 2. capillary path, 3. freezing temperature. if you can eliminate any one of these factors, heave would not occur.
in my humble opinion (which does not agree with the official engineering opinion in my professional association), an isolated retaining wall should be permitted to move freely with the ground around it. who cares if it heaves? as long as it is not attached to something which must not heave.
i don't have any objection to burying the retaining wall footing deep in the ground (in my area that would be about eight feet in order to avoid frost heaving). but the cost of doing so would be exorbitant and would have, in my opinion, no merit or even slight advantage. retaining walls which move with the surrounding soil are not perceived to move. most people would swear on a stack of bibles that they did not move. the fact is that they did move, but so did the rest of the ground around them so the relative movement was not perceptible.
my practice in a very cold area of canada has always been to separate retaining walls from buildings...then to allow them to heave with the soil around them. so far, this philosophy has not got me into any trouble. but who knows about the future? things could change. after all, i'm only 75 years old. even though i am retired, there are still a number of projects which could end up being problematic if my philosophy is wrong.
best regards,
ba |
|