Joints in box culverts and channels - necessity of water tightness

The joints for box culverts and channels must be capable of accommodating movements arising from moisture and temperature changes. Conversely joints aren't essentially designed as watertight excluding the following conditions:

(i)  There is a high likelihood of occurrence of high water table in vicinity of box channels/culverts.The high groundwater level and rainwater seepage via embankment may cause water passing through the joints and washing in soils. Therefore loss of soils may lead to the failure of structures.

(ii) If box channels/culvert are designed in such a way that water flow via joints from the structures causes washing out of bedding materials, requirement of water tightness of joint has to be fulfilled.

 (iii)In cold countries, road salt is sometimes applied on roads above box culvert or at crossings of channels to prevent thawing andfreezing. The leaching of road salts into the joints may cause.