The Ontario Building Code | Strength and Stability
4.1.3.2. Strength and Stability
(1) A building and its structural components shall be designed to have sufficient strength and stability so that the factored resistance, ΦR, is greater than or equal to the effect of factored loads, which shall be determined in accordance with Sentence (2).
(2) Except as provided in Sentence (3), the effect of factored loads for a building or structural component shall be determined in accordance with the requirements of this Article and the following load combination cases, the applicable combination being that which results in the most critical effect:
(a) for load cases without crane loads, the load combinations listed in Table 4.1.3.2.A., and
(b) for load cases with crane loads, the load combinations listed in Table 4.1.3.2.B.
(3) Other load combinations that must also be considered are the principal loads acting with the companion loads taken as zero.
(4) Where the effects due to lateral earth pressure, H, restraint effects from pre-stress,P, and imposed deformation, T, affect the structural safety, they shall be taken into account in the calculations, with load factors of 1.5, 1.0 and 1.25 assigned to H, P and T respectively.
(5) Except as provided in Sentence 4.1.8.16.(1), the counteracting factored dead load, 0.9D in load combination cases 2, 3 and 4 and 1.0D in load combination case 5 of Table 4.1.3.2.A. and 0.9Din load combination cases 1 to 5 and 1.0D in load combination case 6 of Table 4.1.3.2.B., shall be used when the dead loadacts to resist overturning, uplift, sliding, failure due to stress reversal, and to determine anchorage requirements and the factored resistance of members.
(6) The principal-load factor 1.5 for live loads, L in Table 4.1.3.2.A. and LXC in Table 4.1.3.2.B. may be reduced to 1.25 for liquids in tanks.
(7) The companion-load factor 0.5 for live loads, Lin Table 4.1.3.2.A. and LXC in Table 4.1.3.2.B. shall be increased to 1.0 for storage areas and for equipment areas and service rooms referred to in Table 4.1.5.3.
(8) Except as provided in Sentence (9), the load factor 1.25 for dead load, D, for soil, superimposed earth, plants and trees given in Tables 4.1.3.2.A. and 4.1.3.2.B. shall be increased to 1.5, except that when the soil depth exceeds 1.2 m, the factor may be reduced to 1 + 0.6/hs but not less than 1.25, where hs is the depth of soil in metres supported by the structure.
(9) A principal-load factor of 1.5 shall be applied to the weight of saturated soil used in load combination case 1 of Table 4.1.3.2.A.
(10) Earthquake load, E, in load combination case 5 of Table 4.1.3.2.A. and case 6 of Table 4.1.3.2.B. includes horizontal earth pressure due to earthquake determined in accordance with Sentence 4.1.8.16.(4).
(11) Provision shall be made to ensure adequate stability of the structure as a whole and adequate lateral, torsional and local stability of all structural parts.
(12) Sway effects produced by vertical loads acting on the structure in its displaced configuration shall be taken into account in the design of buildings and their structural members.
Table 4.1.3.2.A.
Load Combinations without Crane Loads for Ultimate Limit States
Forming Part of Sentences 4.1.3.2.(2) and (5) to (10)
| Item | Column 1 | Column 2 | Column 3 |
|
| Case | Load Combination(1) |
|
|
|
| Principal Loads | Companion Loads |
| 1. | 1 | 1.4D(2) | --- |
| 2. | 2 | (1.25D(3) or 0.9D(4)) +1.5L(5) | 0.5S(6) or 0.4W |
| 3. | 3 | (1.25D(3) or 0.9D(4)) +1.5S | 0.5L(6)(7) or 0.4W |
| 4. | 4 | (1.25D(3) or 0.9D(4)) +1.4W | 0.5L(7) or 0.5S |
| 5. | 5 | 1.0D(4) + 1.0E(8) | 0.5L(6)(7) + 0.25S(6) |
Notes to Table 4.1.3.2.A.:
(1) See Sentences 4.1.3.2.(2), (3) and (4).
(2) See Sentence 4.1.3.2.(9).
(3) See Sentence 4.1.3.2.(8).
(4) See Sentence 4.1.3.2.(5).
(5) See Sentence 4.1.3.2.(6).
(6) See Article 4.1.5.5.
(7) See Sentence 4.1.3.2.(7).
(8) See Sentence 4.1.3.2.(10).
Table 4.1.3.2.B.
Load Combinations with Crane Loads for Ultimate Limit States
Forming Part of Sentences 4.1.3.2.(2), (5) to (8) and (10)
| Item | Column 1 | Column 2 | Column 3 |
|
| Case | Load Combination(1) |
|
|
|
| Principal Loads | Companion Loads |
| 1. | 1 | (1.25D(2) or 0.9D(3)) + (1.5C + 1.0LXC) | 1.0S(4) or 0.4W |
| 2. | 2 | (1.25D(2) or 0.9D(3)) +(1.0C + 1.5LXC(5)) | 0.5S(4) or 0.4W |
| 3. | 3 | (1.25D(2) or 0.9D(3)) +1.5S | 1.0C + 0.5LXC(4)(6) |
| 4. | 4 | (1.25D(2) or 0.9D(3)) +1.4W | 1.0C(7) + 0.5LXC(4)(6) |
| 5. | 5 | (1.25D(2) or 0.9D(3)) +C7 | --- |
| 6. | 6 | 1.0D(3) + 1.0E(8) | 1.0Cd + 0.5LXC(4)(6) + 0.25S(4) |
Notes to Table 4.1.3.2.B.:
(1) See Sentences 4.1.3.2.(2) to (4).
(2) See Sentence 4.1.3.2.(8).
(3) See Sentence 4.1.3.2.(5).
(4) See Article 4.1.5.5.
(5) See Sentence 4.1.3.2.(6).
(6) See Sentence 4.1.3.2.(7).
(7) Side thrust due to cranes need not be combined with full wind load.
(8) See Sentence 4.1.3.2.(10).