OBC 2006 › Division B
4.1.8.4.
Version 0 — in force 31 December 2006
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- Edition
- OBC_2006
- Division
- B
- Provision
- 4.1.8.4.
- Version
- v0
(1) This Regulation comes into force on December 31, 2006.
Read directly from the regulation's own commencement section.
O. Reg. 350/06 · commencement 2.2.1.1(1)
This version stayed in force until the next edition replaced it. What follows is that edition’s base regulation’s commencement — the takeover that ended this one.
(1) Subject to Sentences (2) and (3), this Regulation comes into force on January 1, 2014.
Read directly from the regulation's own commencement section.
O. Reg. 332/12 · commencement 4.4.1.1(1)
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Tell us what is wrong and we will verify & correct our mapping.
- Edition
- OBC_2006
- Division
- B
- Provision
- 4.1.8.4.
- Version
- v0
(1) This Regulation comes into force on December 31, 2006.
Read directly from the regulation's own commencement section.
O. Reg. 350/06 · commencement 2.2.1.1(1)
This version stayed in force until the next edition replaced it. What follows is that edition’s base regulation’s commencement — the takeover that ended this one.
(1) Subject to Sentences (2) and (3), this Regulation comes into force on January 1, 2014.
Read directly from the regulation's own commencement section.
O. Reg. 332/12 · commencement 4.4.1.1(1)
Provenance
New in this edition — no OBC 1997 predecessor
Base · O. Reg. 350/06 · ext← current
Original — base regulation
OBC 2012 · continues as 4.1.8.4. — Pro
4.1.8.4. — Site Properties
(1) The peak ground acceleration (PGA) and the 5% damped spectral response acceleration values, Sa(T), for the reference ground conditions (Site Class C in Table 4.1.8.4.A.) for periods T of 0.2 s, 0.5 s, 1.0 s, and 2.0 s, shall be determined in accordance with Subsection 1.1.2. and are based on a 2% probability of exceedance in 50 years.
(2) Site classifications for ground shall conform to Table 4.1.8.4.A. and shall be determined using 
S except as provided in Sentence (3).
(3) If average shear wave velocity, S, is not known, Site Class shall be determined from energy-corrected Average Standard Penetration Resistance, 
60, or from soil average undrained shear strength, su, as noted in Table 4.1.8.4.A.,
60 and su being calculated based on rational analysis.
(4) Acceleration- and velocity-based site coefficients, Fa and Fv, shall conform to Tables 4.1.8.4.B. and 4.1.8.4.C. using linear interpolation for intermediate values of Sa(0.2) and Sa(1.0).
(5) To determine Fa and Fv for Site Class F, site-specific geotechnical investigations and dynamic site response analysis shall be performed.
(6) The design spectral acceleration values of S(T) shall be determined as follows, using linear interpolation for intermediate values of T:
S(T) = FaSa(0.2) for T≤0.2 s
= FvSa(0.5) or FaSa(0.2), whichever is smaller for T = 0.5 s
= FvSa(1.0) for T = 1.0 s
= FvSa(2.0) for T = 2.0 s
= FvSa(2.0)/2 for T ≥4.0 s
Editor's note
In the site-coefficient tables for Article 4.1.8.4. (Table 4.1.8.4.A. to Table 4.1.8.4.C., Fa and Fv), the header cells of Tables B and C carry a space between the spectral-acceleration term and the inequality sign as filed in O. Reg. 350/06 (for example 'Sa(0.2) <=0.25'), the note headnotes are in bold, and each footnote marker is followed by an en space; this map reproduces the source as filed, while the e-Laws consolidation removes the header-cell space, removes the headnote bold, and removes the space after each marker. The markers' superscript styling is preserved as filed and varies among the three tables. The table content is otherwise identical and none of these changes was enacted by an amending regulation.
Text · e-Laws consolidated snapshot
Column 1 | Column 2 | Column 3 | Column 4 | Column 5 | ||
Average Properties in Top 30 m | ||||||
Site Class | Ground Profile Name | Average Shear Wave Velocity, | Average Standard Penetration Resistance | Soil Undrained Shear Strength, su | ||
A | Hard rock |
| n/a | n/a | ||
B | Rock | 760< | n/a | n/a | ||
C | Very dense soil and soft rock | 360< |
| su > 100kPa | ||
D | Stiff soil | 180< | 15 ≤ | 50 kPa < su ≤100 kPa | ||
E | Soft soil |
|
| su < 50 kPa | ||
Any profile with more than 3 m of soil with the following characteristics: • plasticity index: PI>20 • moisture content w ≥40%, and • undrained shear strength: su < 25 kPa | ||||||
F | Other soils(1) | Site-specific evaluation required | ||||
S (m/s)Notes to Table 4.1.8.4.A.:
(1) Other soils include:
(a) liquefiable soils, quick and highly sensitive clays, collapsible weakly cemented soils, and other soils susceptible to failure or collapse under seismic loading,
(b) peat and/or highly organic clays greater than 3 m in thickness
(c) highly plastic clays (PI > 75) more than 8 m thick, and
(d) soft to medium stiff clays more than 30 m thick.
| Column 1 | Column 2 | Column 3 | Column 4 | Column 5 | Column 6 |
| Site Class | Values of Fa | ||||
| Sa(0.2) ≤0.25 | Sa(0.2)=0.5 | Sa(0.2)=0.75 | Sa(0.2)=1.00 | Sa(0.2) ≥1.25 | |
| A | 0.7 | 0.7 | 0.8 | 0.8 | 0.8 |
| B | 0.8 | 0.8 | 0.9 | 1.0 | 1.0 |
| C | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 |
| D | 1.3 | 1.2 | 1.1 | 1.1 | 1.0 |
| E | 2.1 | 1.4 | 1.1 | 0.9 | 0.9 |
| F | (1) | (1) | (1) | (1) | (1) |
Notes to Table 4.1.8.4.B.:
(1)See Sentence 4.1.8.4.(5)
| Column 1 | Column 2 | Column 3 | Column 4 | Column 5 | Column 6 |
| Site Class | Values of Fv | ||||
| Sa(1.0) ≤0.1 | Sa(1.0)=0.2 | Sa(1.0)=0.3 | Sa(1.0)=0.4 | Sa(1.0) ≥0.5 | |
| A | 0.5 | 0.5 | 0.5 | 0.6 | 0.6 |
| B | 0.6 | 0.7 | 0.7 | 0.8 | 0.8 |
| C | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 |
| D | 1.4 | 1.3 | 1.2 | 1.1 | 1.1 |
| E | 2.1 | 2.0 | 1.9 | 1.7 | 1.7 |
| F | (1) | (1) | (1) | (1) | (1) |
Notes to Table 4.1.8.4.C.:
(1)See Sentence 4.1.8.4.(5)
Provenance
New in this edition — no OBC 1997 predecessor
Base · O. Reg. 350/06 · ext← current
Original — base regulation
OBC 2012 · continues as 4.1.8.4. — Pro