The last sentence of Section R401.1 of Chapter 4 is amended to read as follows:
Wood foundations in Seismic Design Category D0, D1, D2 or E shall not be permitted.
Section R401.1 “Application” is amended by adding the following paragraph:
Grading related work shall comply with the requirements of this code and the requirements of Thousand Oaks Municipal Code Title 7, Chapter 3 and Section 8-1.24 of the Thousand Oaks Municipal Code for grading regulations, administered by the Department of Public Works, for requirements governing excavation, grading and earthwork construction including fills and embankments.
Section R401.3 “Drainage” is amended by adding the following:
Lots shall be graded to drain to the street or to a disposal area approved by the Building Official and/or City Engineer.
2022 S-66 495
Sec. 8-7.04 Thousand Oaks Municipal Code
The first sentence of Sec. R403.1 “General” is amended to read as follows:
All exterior walls and load bearing interior walls shall be supported on continuous concrete footings, or other approved structural systems which shall be of sufficient design to accommodate all loads according to Section R301 and to transmit the resulting loads to the soil within the limitations as determined from the character of the soil.
Section R403.1.1 “Minimum size” is amended to read as follows:
All foundation and/or slab designs shall be predicated upon a soil analysis. Said design shall not be less than those minimum requirements set forth in Municipal Code Section 8-1.17, Table 1809.7(1) for each soil expansion range.
Post-tensioned slab design, when recommended by the soils engineer, may be used in lieu of the requirements when approved by the Building Official.
In areas where the soil is found to be in an expansive range index over twenty (20), the soil under the footings and slabs shall be pre-saturated in accordance with Table 1809.7(1). Municipal Code Section 8-1.17 for additional requirements.
Section R403.1.5 “Slope” is amended by adding the following:
For structures located in Seismic Design Categories D0, D1, D2 or E, stepped footings shall be reinforced with four one-half (1/2”) inch diameter deformed reinforcing bars. Two (2) bars shall be placed at the top and bottom of the footings as shown in Figure R403.1.5.
Figure R403.1.5
Section R403.1.6 “Foundation Anchorage” is amended to replace 1/2-inch diameter anchor bolts with 5/8-inch diameter anchor bolts.
Section R403.1.7 “Footings on or adjacent to slopes” is amended to read as follows:
Footings shall comply with the requirements of this code and the requirements of Thousand Oaks Municipal Code Section 8-1.17 section 1808.7 for foundations on or adjacent to slopes.
Sections R403.1.7.1, R403.1.7.2 and R403.1.7.4 are hereby deleted.
Section R403.1.8 “Foundations on Expansive Soils” is amended to read as follows:
R403.1.8 Foundations on Expansive Soils. Foundation and floor slabs for buildings located on expansive soils shall be designed in accordance with Section 1808.6 of the California Building Code and Municipal Code Section 8-11.17.
Exception: Slab-on-ground and other foundation systems that have performed adequately in soil conditions similar to those encountered at the building site are permitted subject to the approval of the building official.
R403.1.8.1 Expansive Soils Classifications. Soils meeting all of the following provisions shall be considered to be expansive, except that tests to show compliance with Items 1, 2 and 3 shall not be required if the test prescribed in Item 4 is conducted:
1. Plasticity Index (PI) of 15 or greater, determined in accordance with ASTM D4318.
2. More than 10 percent of the soil particles pass a No. 200 sieve (75 µm), determined in accordance with ASTM D422.
3. More than 10 percent of the soil particles are less than 5 micrometers in size, determined in accordance with ASTM D422.
4. Expansion Index greater than 20, determined in accordance with ASTM D4829.
Section R404.2 “Wood foundation walls” is amended by adding the following sentence:
Wood foundation walls shall not be used for structures located in Seismic Design Category D0, D1, D2, and E.
(§ 6, Ord. 1707-NS, eff. January 1, 2023)