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Home My WebLink About04202010 BSC AO 4 City of West University Place A Neighborhood City ® Recycled Paper Building and Standards Commission Advisory Opinion April 20, 2010 Decision or Action Requested: The Chief Building Official requested an advisory opinion from the Building and Standards Commission for his interpretation of Appendix C Section C-104, insert table Note 3. Not to require a "Suction Test" for "Limited" foundation designs. At the request of David Eastwood, P.E., of GEOTECH Engineering and Testing who believes the Chief Building Official's interpretation of Note 3 is incorrect and does in fact require a "Suction Test" be performed on all soil reports for deep foundations (piers), whether the foundation design is "Limited or Full" based on the city adoption of "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, per Appendix C, Section C-104 inset table, Note 2. Ordinance Reference: See Appendix C, Section C-104 inset table and notes attached. The requirements of Note 2 are modified by Note 3. Chief Building Officials Note 3 allows for a "Limited" soil report when the foundation is Interpretation: designed for a "Structural slab with void space and deep foundations" or "Structural floor with crawl space and deep foundations". This is being interpreted to "Not" require a "Suction Test" Advisory Opinion: The Board voted unanimously in support of the Chief Building Officials interpretation. This opinion is not binding on the Building and Standards Commission. This opinion is subject to being reversed, modified or sustained by subsequent action of the board. Date signed: c'* Z 3 , Z- ow By: - L Chairman uilding and S a ards Commission 1 3800 University Boulevard • West University Place, Texas 77005-2899 • 7139668.4441 • www.westu.org 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: "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 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 "f" 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. 2 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 "below. special exception special exception 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 the office of the City Secretary). For this purpose, the "dry" 3 moisture condition (from which little 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. 4