Q. Explain the Permissible Settlement?

Any foundation may fail in shear or by excessive settlement. The failure due to shear is checked by adopting safe value of bearing capacity. The failure due to excessive settlement can be checked by adopting values of permissible settlement for different structures which will not cause distress to the structure. The Indian Standard Code (IS 1904 - 1986, Third revision) suggests that for most of the concrete structures (flats, factories, offices, library) the angular distortion to be within 11500 normally and 111000 where it is desired to avoid any kind of damage. It also recommends that a maximum total settlement should be limited to the value given in Table 4.10.

Table: Permissible Dflerential Senlement