CC - Item 7A - Soils Report Requirements in Liquefaction ZonesROSEMEAD CITY COUNCIL
STAFF REPORT
TO: THE HONORABLE MAYOR AND CITY COUNCIL
FROM: GLORIA MOLLEDA, CITY MANAGER ,
DATE: JUNE 23, 2020
SUBJECT: SOILS REPORT REQUIREMENTS IN LIQUEFACTION ZONES
SUMMARY
This item is presented to the City Council at the request of Council Member Sean Dang. He
would like to discuss the City's soils report requirements in liquefaction zones. Attached, for
your convenience, is the current policy.
STAFF RECOMMENDATION
That the City Council discuss and provide further direction.
STRATEGIC PLAN IMPACT - None
FISCAL IMPACT - None
PUBLIC NOTICE PROCESS
This item has been noticed through the regular agenda notification process.
Attachment: Soils Report Requirements Policy Memo, June 18, 2020
AGENDA ITEM 7.A
Attachment A
Soils Report Requirements Policy Memo
Dated June 18, 2020
City of Rosemead- Building & Safety Division
POLICY MEMO 06/18/20
(Supersedes 70/75/19 & 4/20/20)
Residential Soils Report Guidelines
The specific requirements for soils reports is addressed in numerous California
State Codes, Los Angeles County amendments, and Los Angeles County internal
policies. These various sources are often misinterpreted, outdated, or misapplied
resulting in confusion on the part of our constituents and developers. This Memo
establishes guidelines on when a "site-specific" soils report (soils report) will be
required and addresses only those residential projects under the scope of the
California Residential Code (CRC) per Section R101.2 (see footnotel). Any projects that
are not within the scope of the CRC must comply with soils investigation requirements
as indicated in the California Building Code (CBC).
New CRC Regulated Residential Structures OUTS/DEthe Liquefaction Zone -
Based on resources available from the State Geological Survey and the Los
Angeles County Department of Public Works, it is understood that City of
Rosemead properties located outside of the liquefaction zones are not likely to
contain expansive, shifting, or questionable soils. Therefore, no soils report will
be required under normal circumstances. The Building Official reserves the
option to require a soils report if additional specific information regarding the
subject site reveals a cause for soil concerns.
New CRC Regulated Residential Structures /NS/DEthe Liquefaction Zone
(Including accessory dwelling units)- Based on CRC R401.4 (see footnote 2), and
due to the determination that expansive, shifting, or questionable soils are
know to be present in the liquefaction zone, the Building Official has determined
to require a site-specific soils report on all new residential construction inside
the liquefaction zone (except for garages & storage structures). The Soils
Engineer will determine what specific analysis and test will be required in order
to make the necessary recommendations for grading requirements and
foundation design.
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The Building Official will consider "soils opinion letters" in lieu of a site-specific
soils report on a case by case basis under the following general conditions:
1) The opinion letter must be from a registered Soils Engineer and stamped
with their seal.
2) The conclusions in the letter must be based on at least two other known
soils reports from within the same soil overlay zone (from the LA County
Soil types map https:Hdata.lacounty.gov/Shape-Files/LA-County-Soil-Types/sz94-
meiu).
3) All the recommendations from the Soils Engineer must be implemented in
the construction plans (including grading and foundation design).
Additionally, the Building Official will consider alternative designs (from a
registered structural Engineer) that are based on actual soils data from the
general area considering worst case liquefaction effects.
CRC Regulated Residential Additions or Alterations- No soils report will be
required for additions or alterations to existing residential structures that are
less than 50% of the existing structure and less than 1000 Sq. Ft. which are
located either inside or outside of the liquefaction zone.
However, a soils report will be required for addition or alteration projects
located within a liquefaction zone which exceed 1000 square feet or 50% of the
existing structure.
This new Policy Memo is consistent in application to the Policy Memo dated
4/20/20 but has been re -written for clarity. Please note that this Memo is meant to
establish internal guidelines for staff to consistently apply code requirements, and is
not designed for public distribution.
Buiing and -Safety Division
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Footnote 1- CRC Section R 101.2
8101.2 Scope
The provisions of this code shall apply to the construction, alteration, movement, enlargement,
replacement, repair, equipment, use and occupancy, location, removal and demolition of detached one -
and two-family dwellings and townhouses not more than three stories above grade plane in height with
a separate means of egress and their accessory structures not more than three stories above grade
plane in height.
Exception: The following shall be permitted to be constructed in accordance with this code where
provided with a residential fire sprinkler system complying with Section R313:
1. Live/work units located in townhouses and complying with the requirements of Section 419 of
the California Building Code.
2. Owner -occupied lodging houses with 5 or fewer guestrooms.
3. A care facility with five or fewer persons receiving custodial care within a dwelling unit.
4. A care facility with five or fewer persons receiving medical care within a dwelling unit.
5. A care facility for five or fewer persons receiving care that are within a single-family dwelling.
Footnote 2- CRC Section R407.4
R401.4 Soil Tests
Where quantifiable data created by accepted soil science methodologies indicate expansive soils,
compressible soils, shifting soils or other questionable soil characteristics are likely to be present, the
building official shall determine whether to require a soil test to determine the soil's characteristics at a
particular location. This test shall be done by an approved agency using an approved method.
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