POLICY DIRECTIVE NO. G-12
SUBJECT:
ENGINEERED FOUNDATION
APPROVAL DATE:
LAST REVIEW DATE:
June, 1997
REFERENCE:
A.
POLICY:
1.
This guideline is to assist in determining when a soils investigation and
subsequently engineered footing/foundation design may be required prior to the
issuance of a building permit.
2.
Should the City of Chilliwack be aware of geologically unstable soils at a
building site, or reasonably expect that soil conditions exist at that site which
could result in the failure of a building or works foundation, then a soils
investigation performed by a professional engineer experienced in such matters
shall be required. Furthermore, an engineered footing/foundation design may be
required, and if so, it shall be signed, sealed, and dated by a professional engineer
registered in the Province of B.C.
3.
Although not an exclusive list, the following examples of site conditions will
serve to illustrate where special attention must be paid to soils investigations and
subsequently to footing/foundation designs, for it is these types of areas where a
risk of a foundation failure is probable:
(a)
Existence of peat soils or peat lenses;
(b)
Land subject to erosion or flooding;
(c)
Land subject to land slip, rock falls, debris torrents, and avalanche;
(d)
Sloping lands particularly when the slope gradient exceeds 30% (i.e. a
vertical rise of 3 to a horizontal run of 10);
(e)
Land which is subject to a high water table or poorly drained land which
results in a low bearing capacity of the soils;
(f)
Land which has been filled and the proposed foundation footings will not
extend to a sufficient depth to bear on undisturbed soil;
(g)
Land which is comprised of soils which have differential bearing capacity;
(h)
Any soils or site condition which could cause or result in a failure of the
footing/foundations for a structure.
Policy Directive No. G-12
ENGINEERED FOUNDATION
Page 2 of 2
POLICY (continued)
4.
Whenever it is determined a soils investigation is required, and where appropriate
engineered footing/foundation designs are required, the Building Inspector shall
advise the owner, in writing, of these prerequisites. The letter will outline those
site conditions, such as those described in paragraph 3 above, that have led to the
decision that a soils investigation is required.
5.
With respect to slope stability, should a retaining wall be required, either by the
City or the owner, a soils investigation performed by a professional engineer
experienced in such matters shall be required. Furthermore, an engineered design
of the retaining wall shall be completed, signed, sealed, and dated by a
professional engineer prior to the issuance of the building permit.
______________________________
Chief Administrative Officer