HomeMy WebLinkAbout04012010 BSC Agenda Item 4
STAFF REPORT
Business of the Building and Standards Commission
City of West University Place, Texas
AGENDA OF: April 1, 2010 DOCKET NO.: 10-02
DATE SUBMITTED: March 24, 2010 DEPARTMENT OF ORGIN: Development
Services
PREPARED BY: John R. Brown, MCP, CFM
Chief Building Official PRESENTER: John R. Brown
SUBJECT: Request an advisory opinion of
the Geotechnical Report for foundations, STAFF PRESENTER:
Note 2 & 3. John R. Brown, MCP, CFM
Chief Building Official
ATTACHMENTS: Code section C-104, Document # FPA-SC-04-0, Rev. #0 11 April 2001
STAFF SUMMARY
Background:
Since the incorporation of the local foundation requirements, as listed in Appendix C section C-104(3)
Table Inset, when an Engineered foundation design was submitted designed to the "Limited" design requirements
note 1, 2 & 3 have been interpreted as not requiring the special additional test listed under note 4.
David Eastwood, a registered profession engineer, representing GeoTech Engineering and Testing
Company came to my office and has called me on more than one occasion where he stated that a "suction" test is
required on any and all geotechnical reports for the city of West University Place. The basis for his interpretation is
that note 2 of the Table Inset refers to compliance with "Recommended Practice for Geotechnica/ Explorations and
Reports" published by the Structural Committee of the Foundation Performance Association, Houston, Texas
(Document # FPA-SC-04-0, Rev #0, 11 April 2001. In that document Section 1.3 Laboratory Testing states:
The Geotechnical Engineer should perform sufficient laboratory testing to comply with the requirements of
standard codes and local practices. However, the following laboratory testing is recommended as a minimum and
(f) of the listed recommendations states: For lots that have predominately cohesive soils, testing at each boring
location should be done to determine soil suction. Soil suction test should be conducted using the transistor
psychrometer method, the filter paper method or other methods that give similarly reliable suction values. Where
suction testing is recommended, it should be done at sample depths of 2-ft, 4-ft, 6 -ft, 8-ft, 10 ft, 12-ft, 16 ft and 20-
ft, but may be terminated earlier at the depth of constant suction, if determined.
My interpretation of notes 2 & 3 is when a foundation is designed where only a "Limited" Geotechnical
report is required; the listed requirements of note 4 are not required, i.e. "suction" testing, etc.
My interpretation is consistent with all previous Chief Building Officials since enforcement began, per Ms.
Scarcella, the city planner and previous CBO,
I am requesting the Boards advisory opinion on this interpretation of notes 2 & 3.
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Appendix C, Technical Codes
Sec. C-104. International Building Code.
1. The administrative officer is the building official. All hearings, variances etc. are handled by the BSC.
2. On sites primarily used for residential purposes, all roofs must have Class A or better fire residence, as
determined under Section 1505. 1, except that wooden roofing materials are forbidden.
3. The foundation for each new building (and each new addition to a building) must meet all the criteria
in this section, as applicable. Exception: If the building or addition does not contain habitable space (as
defined in the IBC), it must meet only the requirements for "nonhabitable space," as indicated below. In
this section:
"AMA Lab" means a laboratory accredited by the American Association for Laboratory Accreditation on
the basis of ISO/IEC 17025:1999 ("general requirements for the competence of testing and calibration
laboratories").
"RLPE" means a licensed or registered professional engineer of the State of Texas who is:
(1) Listed with the State Board of Professional Engineers in either the civil or structural branch of
engineering (but, from and after May 1, 2006, listing in the structural branch is required);
(2) Employed by a registered engineering firm of the State of Texas; and
(3) (Unless waived by the BSC as provided in 'T" below) covered by professional errors and omissions
insurance that: (i) has limits of at least $250,000.00 per claim (and at least $500,000.00 per year,
aggregate) and (ii) has effective dates-including any retroactive coverage date-that include the entire
period when the person provides services or takes actions regulated by this section.
"RLGE" means a person who is:
(1) Either. (a) a registered professional geoscientist of the State of Texas, or (b) a licensed or registered
professional engineer who is listed with the State Board of Professional Engineers in a relevant branch of
engineering (civil, structural or geological) and employed by a registered engineering firm of the State of
Texas; and
(2) Covered by professional errors and omissions insurance that. (i) has limits of at least $250,000.00
per claim (and at least $500,000.00 per year, aggregate) and (ii) has effective dates-including any
retroactive coverage date-that include the entire period when the person provides services or takes actions
regulated by this section.
a. Engineering. Foundations must be constructed in accordance with complete plans and specifications
prepared, signed and sealed by a RLPE. The plans and specifications must be prepared specifically for the
site of the work, and they must meet criteria as to scope, content and form specified by the building
official. If there are existing trees (either to remain or to be removed) within 20 feet of a foundation, the
RLPE must acknowledge, in writing, that the trees have been taken into account in the preparation of the
plans and specifications.
b. Basic standards. Each foundation must be an approved basic type listed in the following chart. In
addition, the design of each foundation must be supported by a geotechnical report and special
engineering certification, to the extent indicated in the following chart.
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TABLE INSET:
Approved Basic Types. See Note Geotechnical Report. Special Engineering
1. See Notes 2 and 3. Certification. See Note 4.
Structural slab with void space and Limited Not required
deep foundations
Structural floor with crawl space and Limited Not required
deep foundations
Stiffened structural slab with deep Full Required
foundations
Stiffened non-structural slab with Full Required
deep foundations
Mixed-depth system for all new Full Required
building construction
Mixed-depth system for building Full Required
additions with deep foundations
Another type approved by special As specified in the As specified in the
exception issued by the BSC. See special exception special exception
"f, " below.
Note 1. Approved Basic Types . Types of foundations are defined and described in "Foundation Design
Options For Residential and Other Low-Rise Buildings on Expansive Soils" published by the Structural
Committee of the Foundation Performance Association, Houston, Texas (Document # FPA-SC-01-0, Rev
#0, 30 Jun 04, marked "For Website Publishing"), a copy of which is on file in the City Secretary's office
("FDO").
Note 2. Geotechnical Report, Standards. The plans and specifications for each foundation must be based
on a written geotechnical report prepared, signed and sealed by a RLGE. The report must cover all testing
and site evaluation, and all must meet all applicable criteria in "Recommended Practice for Geotechnical
Explorations and Reports" published by the Structural Committee of the Foundation Performance
Association, Houston, Texas (Document # FPA-SC-04-0, Rev #0, 11 April 2001, issued for website
publishing), a copy of which is on file in the City Secretary's office. The report may be limited as
allowed by Note 3 below. The minimum depth of borings is 20 feet in all cases. All required tests and
other laboratory work must be performed by an A2LA Lab.
Note 3. Geotechnical Report, Scope. "Limited" indicates that the geotechnical testing, evaluation and
report may be limited to a determination of the appropriate depth for the deep foundations (but the deep
foundation components must meet the other criteria applicable to them). "Full" indicates that the
geotechnical testing, evaluation and report must cover all foundation components.
Note 4. Special Engineering Certification. Where indicated as "required," for a particular type of
foundation, the RLPE must certify that the plans and specifications were prepared to achieve a soil-caused
foundation movement potential of one inch or less, and that the RLPE used the estimated depth of the
active zone and at least two of the following methods to prepare the plans and specifications:
(1) Potential vertical rise (PVR) determined in accordance with Test Method Tex-124-E, Rev. January 1,
1978/December 1982, Texas State Department of Highways and Public Transportation, Materials and
Test Division, "Method for Determining the Potential Vertical Rise, PVR" (a copy of which is on file in (V
the office of the City Secretary). For this purpose, the "dry" moisture condition (from which little
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shrinkage is experienced, but where volumetric swell potential is greatest) shall be used for each sample
and test.
(2) Swell tests performed in accordance with ASTM D4546-03, "Standard Test Methods for One-
Dimensional Swell or Settlement Potential of Cohesive Soils" as last revised prior to June 1, 2004.
(3) Suction and hydrometer swell tests performed in accordance with ASTM D5298-03 "Standard Test
Method for Measurement of Soil Potential (Suction) Using Filter Paper" and ASTM D6836-02 "Standard
Test Methods for Determination of the Soil Water Characteristic Curve for Desorption Using a Hanging
Column, Pressure Extractor, Chilled Mirror Hygrometer, and/or Centrifuge," as such methods were last
revised prior to June 1, 2004.
c. Foundations, Deep Support Components. Deep support components must be of an approved type.
Approved types are listed below. In this list, types of deep support components are defined and
described in FDO.
(1) Drilled and under-reamed concrete piers.
(2) Drilled straight-shaft concrete piers.
(3) Auger-cast concrete piles.
(4) Another type approved by special exception issued by the BSC. See "h," below.
d. Reinforcement. Reinforcement for each foundation must be of an approved type. Approved types
are listed below. In this list, types of reinforcement are defined and described in FDO.
(1) Deformed bar reinforcing.
(2) Another type approved by special exception issued by the BSC. See "h," below.
e. Observation and Certification. Each foundation must be professionally observed and must be
certified by an RLPE, as more fully described below:
(1) Observations must:
(i) Be performed either by the certifying RLPE or by one or more persons under that RLPE's direct
supervision and control whose professional qualifications are approved by the RLPE (any such person
may be an RLGE, with respect to geophysical matters);
(ii) Include actual measurement of piers, fill, compaction, reinforcement, forms, materials, dimensions,
structural elements, attachments, etc. before the work is covered or concrete is placed (Note: dimensions
of an underground element may be measured or estimated from the forms, boring or cavity for the
element, before pouring or filling);
(iii) Be performed continuously during placement of concrete; and
(iv) Be documented in a form and manner approved by the building official (which may include
photographs).
(2) Certifications must:
(i) Refer to and be based upon the professional observations required by this section;
(ii) State that the work complies with the plans and specifications last approved by the building official
(with any field changes that are ordered by the RLPE and reported to the building official and that comply
with applicable regulations);
(iii) Comply with criteria as to form and content as maybe specified by the building official;
(iv) Be signed and sealed by the certifying RLPE; and
(v) Be filed with the building official.
(3) Certifications may:
(i) Rely in part upon an attached certification by a RLGE, as to geophysical matters;
(ii) Rely in part upon an attached certification by an A2LA Lab, as to materials testing; and
(iii) Be expressed as a professional opinion based on RLPE's knowledge, information and belief that
does not constitute a guarantee or warranty, express or implied.
Before framing or other work commences stop a foundation (and before the foundation is otherwise
covered), the permittee must obtain written acknowledgment from the building official that the certification
for the foundation was duly filed as required above. Certifications, plans, specifications and related items
must be kept on file by the City, available for public inspection, for the retention period required by public
records laws and may be kept longer (for an indefinite period of time).
f. Curing concrete. All concrete piers, footings and foundations must be cured for at least 72 hours
before any significant load is placed on them.
g. Nonhabitable space. This paragraph applies to buildings and additions to buildings that do not
contain habitable space (as defined in the IBC). Footings, beams and monolithic slabs with integral
footings shall be constructed of masonry or reinforced concrete rated at 2,500 psi 0 28 days (except for
accessory buildings with only one story and less than 200 feet of gross floor area). Each building must
have footings, beams and slabs of reinforced concrete assuming a soil bearing capacity of 1,500 psi; see
R-403 of the IRC. All footings and beams shall be at least 24 inches deep and at least 12 inches wide
and shall extend at least 12 inches below the undisturbed soil level. Reinforcement for concrete footings
and beams must include at least two #5 deformed bars top and bottom, grade 60 (or better). Slabs must
be reinforced with #4 deformed bars, grade 60 (or better), spaced no wider than 16-inches on center
each way. Post-tensioned slab or cable foundations are not allowed.
h. Special Exceptions. The BSC may issue a special exception from any requirement in subsection "a"
through "g," above, but only upon a showing that:
(1) the requirement will not affect life safety or the performance of a structure; or
(2) an alternate requirement to be imposed by the special exception will provide equal or better
protection for life safety and long-term structural performance.
However: (i) unless the basic type of foundation is "structural slab with void space and deep foundations"
or "structural floor with crawl space and deep foundations," as described in this section, the BSC may not
issue a special exception waiving any requirement for an RLPE to have professional errors and
omissions insurance, in whole or in part; and (ii) the BSC may not waive any requirement for an RLGE to
have such insurance. In connection with any special exception, the BSC may require that the applicant
provide supporting engineering data and opinion, and the BSC may impose conditions to carry out the
purpose and intent of applicable regulations.
4. Sheathing (gypsum board) and trim must comply with this section, as follows:
(1) All walls and ceilings within a R-1, R-2, R-3 and R-4 type occupancy shall be sheathed with Type X
gypsum board at least 5/8-inch (15.9 mm) thick. Exception: Where applicable code (IBC, IRC) requires
otherwise for moisture protection.
(2) All exterior trim (e.g., soffit, fascia, window trim, chimney trim, etc.) must be made of treated lumber
or noncombustible materials.
5. Structural elements, engineering, etc. must comply with the following section:
A. Scope.
(1) The structural elements for the following must meet the criteria in this section, as applicable:
(a) Each new building (and each addition to an existing building) containing habitable space and having
either a,gross floor area of 485 square feet or more or a finished floor height greater than four feet; and
(b) Each accessible deck, porch, balcony, walkway and similar structure with a finished floor height
greater than four feet.
(2) This section does not apply to foundation elements observed and certified under another section.
B. Definitions. In this section:
Height is measured from the "standard base level" as provided in the Zoning Ordinance.
A2LA Lab means a laboratory accredited by the American Association for Laboratory Accreditation on
the basis of ISO/IEC 17025:1999 ("general requirements for the competence of testing and calibration
laboratories").
RLPE means a registered or licensed professional engineer of the State of Texas who is:
(a) Listed with the State Board of Professional Engineers in either the civil or structural branch of
engineering (but, from and after June 1, 2006, listing in the structural branch is required);
(b) Employed by a registered engineering firm of the State of Texas; and
(c) Covered by professional errors and omissions insurance that: (i) has limits of at least $250,000.00
per claim (and at least $500,000.00 per year, aggregate) and (ii) has effective dates-including any
retroactive coverage date-that include the entire period when the person provides services or takes
actions regulated by this section.
C. Engineering, Plans and Specifications. Structural elements must be constructed in accordance with
complete plans and specifications prepared, signed and sealed by a RLPE. The plans and specifications
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must be prepared specifically for the structure in question, and they must meet criteria as to scope,
content and form specified by the building official.
D. Specific Requirements.
(1) Framing, Sheathing. All framing must include full exterior sheathing with structural elements (or
blocking) along all joints. The plans must indicate the type, size and spacing of fasteners. All sheathing
must be minimum 7/16" structural wood panels. In walls where plumbing, drain, waste or vent lines are
located, the framing members must be two inches by six inches or larger.
(2) Trusses, Joists, Etc.
(a) The species and grade of all lumber used for trusses, joists, purlins, purlin supports or similar
elements must be specified in the plans.
(b) The length, spacing and direction of trusses and joists must be specified in the plans.
(c) Each manufactured wood truss must comply with applicable requirements of the "National Design
Standard For Metal Plate Connected Wood Truss Construction" published by Truss Plate Institute (TPI),
1-2000 Ed. The design and specifications of any truss built on the site (and any other truss not already
certified as meeting such TPI requirements), must be included in the plans and specifications.
(3) Utility-grade lumber may not be used for joists, rafters or vertical framing.
(4) Windspeed clips and straps must meet these minimum requirements:
(a) Clips: Simpson Strong Tie H2.5 or equal, installed on every other member as follows: rafter to
double top plate.
(b) Straps/rafters: Simpson Strong Tie LSTA 18 or MSTA 18 or equal installed rafter to rafter over
ridge, on every other member.
(c) Strap/beams for porches, patios, garage doors: Simpson Strong Tie LSTA 15 or MSTA 15 or equal,
installed two on each end of each beam, strapped to post/support.
(d) Purlins: Simpson Strong Tie LSTA 15 or MSTA 15 or equal, installed to rafters and spaced no wider
than 48 inches on center, also installed on purlin braces and tied to purlins and brace supporting
members.
E. Observation and Certification. Structural elements must be professionally observed and must be
certified by an RLPE, as more fully described below:
(1) Observations must:
(a) Be performed either by the certifying RLPE or by one or more persons under that RLPE's direct
supervision and control whose professional qualifications are approved by the RLPE;
(b) Include actual observation of structural elements and attachments in crawl spaces before they are
covered by floors or other materials;
(c) Include actual observations of each beam, joist, rafter, truss and similar element, including each
related weld and high-strength bolt: (i) after all required plumbing, electrical and mechanical "rough-in"
inspections have been passed and all expected "notching," boring and similar work has been done, and
(ii) before the item is covered; and
(d) Be documented in a form and manner approved by the building official (which may include
photographs).
(2) Certifications must:
(a) Refer to and be based upon the professional observations required by this section;
(b) State that the portions of the work required to be observed comply with the plans and specifications
last approved by the building official (with any field changes that are ordered by the RLPE, reported to
the building official and in compliance with applicable regulations);
(c) Comply with criteria as to form and content as may be specified by the building official;
(d) Be signed and sealed by the certifying RLPE; and
(e) Be filed with the building official.
(3) Certifications may:
(a) Rely in part upon attached certifications by: (i) an A2LA Lab, as to materials testing, and (ii) an
inspector certified by the City of Houston, as to welds or high-strength bolts (or meet the provisions of
Section 1704.3.3 of the IBC); and
(b) Be expressed as a professional opinion based on the RLPE's knowledge, information and belief that L0
does not constitute a guarantee or warranty, express or implied.
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Before any a beam, joist, rafter, truss, weld, high-strength bolt or similar element is covered: (i) all
required city inspections relating to that element must be passed, and (ii) the permittee must obtain
written acknowledgment from the building official that the certification for that element was duly filed as
required above. For any given building, there may be more than one certification filed.
After a beam, joist, rafter, truss, weld, high-strength bolt or similar element has been observed and
certified, as provided above, it may not be notched, bored or structurally altered without: (i) a new or
amended permit, if required, and (ii) a new observation and certification, in accordance with this section.
Certifications, plans, specifications and related items must be kept on file by the city, available for public
inspection, for the retention period required by public records laws and may be kept longer (for an
indefinite period of time).
F. Special Exceptions. The BSC may issue a special exception from any requirement in subsection "A"
through "E", above, but only upon a showing that:
(1) The requirement will not affect life safety or the performance of a structure (for its estimated useful
life); or
(2) An alternate requirement to be imposed by the special exception will provide equal or better
protection for life safety and long-term structural performance.
In connection with any such special exception, the BSC may require that the applicant provide supporting
engineering data and opinion, and the BSC may impose conditions to carry out the purpose and intent of
applicable regulations.
6. Delete: Appendices A (Employee Qualifications), B (Board of Appeals) and D (Fire Districts).
7. In Section 1612.3, the referenced flood study (with FIRM and FBFM) means the "Flood Insurance
Study for Harris County, Texas and Incorporated Areas," dated June 18, 2007 (revision date), with the
most effective Flood Insurance Rate Maps and/or Flood Boundary- Floodway Maps (FIRM and/or FBFM)
dated June 18, 2007 (map revised date).
8. In Section 3410.2, the blank date shall mean the date of that edition of the IBC, as adopted by the
City.
9. If work done on a building within any 12-month period constitutes, cumulatively, a "substantial
improvement" (as defined in the City's flood damage prevention ordinances, e.g., Section 18-272 of this
Code), the owner shall--to the extent reasonably practicable--make the building comply with current code
provisions for new construction regarding: (i) structural components (except foundations) and (ii) life
safety features (hand and guard rails, smoke detectors, safety glazing, ground fault circuit interrupters,
arc-fault combination breakers, emergency egress from sleeping rooms, locking devices on required
egress components, etc.). To determine the "market value" of a pre-existing building, the most current
tabulation of square foot construction costs published by the International Code Council (usually as part
of "Building Valuation Data." see e.g., www.iccsafe.org/cs/techservices) shall be used.
10. If a building is "substantially damaged" (as defined in the City's flood damage prevention
ordinances, e.g., Section 18-272 of this Code), the owner shall cause it to be: (i) secured to prevent entry
by unauthorized persons, within 24 hours after all embers are extinguished (or other damaging
occurrence has ended) and (ii) either demolished (in accordance with Chapter 18 of this Code) or rebuilt
in conformity with applicable technical codes as though it were a new building. Normal permits (including
certificate of occupancy) are required. Work to demolish or rebuild must begin within 60 days following
the date the occurrence ends and must be completed within a reasonable time, but not longer than the
time allowed by the applicable permit(s). To determine the "market value" of a pre-existing building, the
most current tabulation of square foot construction costs published by the International Code Council
(usually as part of "Building Valuation Data," see, e.g., www.iccsafe.org/cs/techservices) shall be used.
(Ord. No. 1775, § 1(app. A), 9-27-2004; Ord. No. 1791, § 1(app. A), 5-2-2005; Ord. No. 1823, § 1, 5-8-
2006; Ord. No. 1824, § 1, 5-8-2006; Ord. No. 1896, § 1, 5-11-2009)
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