Paper format: National Exams, December 2015 — 07-Str-B5 Foundation Engineering. Three hours, open book, any non-communicating calculator permitted. Six questions of equal value (30 marks each); five constitute a complete paper and only the first five in the answer book are marked. All six are solved here. This subject is pure geotechnical engineering.
Reference texts (the books an open-book candidate should have on the desk for this subject):
- Canadian Geotechnical Society, Canadian Foundation Engineering Manual (CFEM), 4th ed. — the Canadian limit-states framework, geotechnical resistance factors, pile design.
- B. M. Das, Principles of Foundation Engineering, 9th ed. — bearing capacity, shape/depth/inclination factors, retaining walls, pile groups.
- R. F. Craig / J. Knappett, Craig's Soil Mechanics, 9th ed. — Skempton's bearing-capacity factors, Skempton–Bjerrum settlement correction, slope-stability charts.
- D. W. Taylor, Fundamentals of Soil Mechanics — the stability-number charts used in Question 3.
- M. J. Tomlinson & J. Woodward, Pile Design and Construction Practice, 6th ed. — adhesion factors, equivalent-raft settlement, block failure of pile groups.
Check — assumptions adopted across this paper. The examination omits several parameters that a foundation designer must have; each is adopted explicitly here and flagged again where it is used. (1) Question 2 and Question 5 give bulk unit weights but no groundwater table — effective stresses are computed with the quoted unit weights acting as effective weights (i.e. no free water in the profile); if instead the water table stood at ground level the effective stresses roughly halve and the computed consolidation settlements roughly double, and that sensitivity is reported. (2) Question 2 gives no allowable settlement — 50 mm total is adopted, the upper end of the CFEM 4th ed. range for framed structures. (3) Question 4 gives only the submerged unit weight of the foundation sand; the moist unit weight above the water table is taken as 20.0 kN/m3, consistent with the quoted $\gamma^{\prime} = 10.2$ kN/m3. (4) Concrete unit weight is taken as 24 kN/m3 throughout. (5) Where a question states only a factor of safety, the gross definition is used for shallow foundations sized on total load and the net definition where the question separates net pressure, and the convention used is stated in each answer.
