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HomeMy WebLinkAboutItem 5.4 Variance Heritage Commons Phase I (2) CITY OF DUBLIN AGENDA STATEMENT 450 , 0 CITY COUNCIL MEETING DATE: February 13, 1984 SUBJECT: Request for Variance to Section 2903 (c ) of the Building Code EXHIBITS ATTACHED: 1 . January 18, 1984 letter from Heritage Auxiliary Builders . 2 . September 28, 1982 letter from Harding Lawson Associates to Heritage Auxiliary Builders . 3 . January 18, 1984 letter from Harding Lawson Associates to Heritage Auxiliary Builders . 4 . Section 2903 (c ) of the Building Code . 5 . Draft Resolution Granting Variance . RECOMMENDATION: The Variance be granted subject to the condition that a hold harmless, in a form acceptable to the City Attorney, be executed and recorded which would hold the City, its officers and contractors harmless from any damages that may occur as the result of the granting of this Variance. FINANCIAL STATEMENT: There would be no additional revenues or expenses. DESCRIPTION: Section 2903 (c) of the Alameda County Building Code as adopted by the City of Dublin, and the Dublin Building Code adopted by Ordinance 02-84 requires that when fill is to be used to support a building, the fill shall be continuously inspected. This project is the Heritage Commons Development located at Stagecoach Road and Amador Valley Boulevard. According to the soil engineers report, fill was placed between July 28, 1982 and August 26, 1982, and the inspection of the placement of the fill was on an intermittent basis . The grading in the project is essentially completed. --Most of the western portion of the site is in cut, or has very shallow fill . The maximum depth of fill is about 10 on the eastern= portion of the site. Applications for building permits are now pending. The alternatives are to remove the fill and recompact, or to extend the foundation piers through the fill and extend them into the natural ground a sufficient depth to support the loads . This approach virtually ignores the capability of the fill to support loads . The requirement of continuous inspection is to assure that: 1 . The materials used for the fill are suitable. 2 . The fill is properly compacted. ' '3 . The site was properly prepared,! prior to placement of the fill. 4 . Conditions encountered are as anticipated in the soil invest- igation report, and when unanticipated conditions occur, proper _ steps are taken to address these problems . _ 5 . Subdrains are properly installed in natural drainage swales, and when excessive moisture conditions are encountered. 6 . That buttress fills are properly keyed into the natural ground. 7 . That fills are keyed in the slopes on hillside developments . The following apply to this specific site: 1 . The materials used in the fill were the natural, on site, soils. There was no imported materials. 2 . Compaction of fill can be reasonably verified through tests taken at random locations and depths . 3 . The soil engineers indicate that the site was properly prepared by stripping the upper 2 to 3 inches of topsoil, scarifing the soil to a depth of six inches and compacted to 90 percent relative compaction. Items 4 , 5, 6, and 7 do not apply to this site because the site is relatively flat with no drainage swales running through the graded area. --------------------------------------------------------------------------- ITEM NO. COPIES TO: Heritage Auxiliary Builders Harding Lawson Assoc. The soil engineer, Harding Lawson Associates, has provided the following statement : "On the basis of our observations and tests, we conclude that the grading has been completed satisfactorily and in accordance with the project plans and specifications . Our tests indicate that the fills have been compacted to at least 90 percent relative compaction. In our opinion, the fill will provide adequate support for the planned structures . " In order to grant a Variance, the City Council must find that the Variance is consistant with the intent of the Code and that granting the Variance will not lessen the protection to the people of the City of Dublin and to the property situated therein. In view of the specific conditions applicable to this site, it is the opinion of the Building Official the granting of this Variance will be consistent with the purpose of the code, and will not lessen the protection to people or property. r' !a s a• . a, HERITAGE AUXILIARY January 18, 1984 BUILDERS Mr. Victor Taugher City of Dublin. 6500 Dublin Blvd. , Dublin, Ca. 94568 Regarding: Heritage Commons, Phase I Amador Valley Blvd. , and Stagecoach Road Dear Mr. Taugher: Enclosed please find a copy of original grading permit with County of Alameda, final geological report on grading dated September 28, 1982 along with cover letter to County of Alameda in regards to finalizing grading. Also, enclosed is supple- mental report dated January 18, 1984 we requested from Harding Lawson Associates. Hope this will ease your concern and if you feel you cannot make this decision without reservations, please make arrangements for this to be an item on agenda for January 23, 1984 before the City Council. Very truly yours, HERITAGE AUXILIARY BUILDERS Allen Steen President AS/bb encl: %its M n egg . o PNIg 222 SEVENTH STREET SAN FRANCISCO pF� CALIFORNIA 94103 .0�r\SQ� \ON 415/431-1074 �v`�p\No COI Y OF ALAMEDA PU�_.IC WORKS AGENCY 0 ALAMEDA CO1'N'Pl' FLOOD C0N7`IZOI. , AND CONSERVATION DISTRICT W B 399 Elmhurst Street • Heyward, CA 94544-1395 • (415) 881-6470 GRADING PERMIT APPLICATION NO. 67006 Permittee's Name H.A.B. Inc. Date August 3, 1932 Address 222 - 7th St. , San Francisco, CA 94103 Phone 431-1074_ Location of proposed work Amador Valley Boulevard @ Stagecoach Road Dublin. CA Type of grading authorized: Fees: Regular ELI Engineered Permit (29110002) $ 10.00 Investigation b 19,600.00 Quantity 24' �c90 Cu. Yds. Inspection (9600) $ XllO�QaQUQCX The term of this permit shall not exceed Surety: Cash (9580) $ 120 days from date of issuance Bond $ 19,610.00 QConcurrent with Tract Contract Total $ xvmam ❑ Other Misc. Fees $ Record of payment: $ /9, 6/U• °-D Received `��Z � Receipt No. � `Iu2 By This permit is issued SUBJECT TO the terms and conditions of the Grading Ordinance (Ala- meda County Ordinance Code, Title 7, Chapter 9 Ordinance No. 82-17) and to the applicat- ion and the approved plans and specifications made a part hereof by reference. The Grading Ordinance and the approved plans and specifications are by this reference in- corporated in this permit as if set forth at length. No change of any nature in the app- lication, the plans and specifications, or in the work to be performed thereunder, shall be made unless such change shall have first been approved in writing by the Director of Public Works and an amendment to this permit executed. Agreed and Accepted: `9ppl ic:ant And it is further provided that this permit is issued subjpct to the Cite of nunlin's adoption of the Alameda County Grading Ordinance No. 82-17 Final Geotechnical Q YES NO Approved for Issuance Report required X Directo of P ,lir:Works Tract or Parcel Map No. 4950 By Date Applicants Copy 1 i Harding Lawson Associates September 28 , 1982 8424 ,002 .03 Heritage Auxilary Builders 2460 Vista Del Monte Concord, California 94520 Attention: Mr. James Crumpler Gentlemen: Progress Report Soil Engineering Services Heritage Commons , Phase I Dublin, California This report summarizes the soil engineering services we provided during site grading for Heritage Commons , Phase I , Dublin, California. The grading was performed during the period July 28 and August 26 , 1982 . Recommendations con- tained in a report by Bay Soils , Incorporated dated January 13 , 1981 and the project plans and specifications .:by Kinney Engineering , Incorporated were the guidelines for the work. Areas to be graded were stripped of surface vegetation and the upper 2 to 3 inches of topsoil. The exposed soil was scarified .to a depth of 6 inches , moisture conditioned, and compacted to at least 90 percent relative compaction* . Fill materials were placed in layers 6 to 8 inches in loose thick- ness , moisture conditioned and similarly compacted. Representative samples of the fill material were compacted in our laboratory in accordance with the ASTM D1557-78 compaction test procedure to determine optimum moisture content and maximum dry density . Supplemental compaction tests were also performed in the field to verify the maximum dry density and check for material variation. * Relative compaction refers to the in-place dry density of soil expressed as a percentage of the maximum dry density of the same material, determined by the ASTM D1557-78 laboratory test procedure . Engineers 2430 Stanwell Dr. Telephone Alaska Hawaii Texas Geologists& Suite 110 415/687-9660 California Illinois Washington Geophysicists Concord,CA 94520 Colorado Nevada Saudi Arabia Harding Lawson Associates September 28 , 1982 8424 ,002 . 03 Mr. James Crumpler Heritage Auxilary Builders Page 2 Our technician was on the site intermittently during site grading to observe the earthwork construction methods and perform field density tests in compacted fill to evaluate relative compaction. When the required degree of compac- tion was not achieved, the contractor was notified and the area of low compaction was rerolled and retested until satisfactory results were attained prior to placement of additional fill . A summary of the field density tests performed to date is presented on Plates 1 and 2 . On the basis of our observations and tests , we conclude that the grading has been completed satisfactorily and in accor- dance with the project plans and specifications . Our tests indicate that the fills have been compacted to at least 90 percent relative compaction. In our opinion, the fill will provide adequate support for the planned structures . We trust this provides the information required at this time. If you have questions , please call. Yours very truly, HAARDI'NG' �LAWSSOON ASSOCIATES CSC 'J Cecil B. Wood Civil Engineer - 18671 CBW/md 3 copies submitted Attachments - Plate 1 and 2 aD u- �= o O C u Q- r C C V a O O '%A Location �, C `� a� U Remarks a E z' ' o `+ O a d O w :2 V ~ (1) SOUTH EAST (2) (3) 4 1 40 345 352. 817 . 2 109 119 92 2 55 450 352. 517 . 7 110 119 92 3 90 350 353.0 17 . 3 110 119 92 4 105 450 353.0 17 .6 109 119 92 5 185 300 355 . 214 . 5 114 119 96 6 190 420 355 . 116 . 9 110 119 92 7 120 295 356 . 518 .0 109 118 92 8 130 380 357 .016 .9 110 118 93 9 155 475 356 .0 16 . 2 110 119 92 10 230 483 357. 1 15 .5 110 119 92 11 40 295 359 .0 18 . 4 109 118 92 12 45 360 359 . 013. 7 109 118 95 13 50 430 359 .0 16 . 4 112 119 94 14 63 490 359 .0 15 .5 112 119 94 15 130 500 357 .5 15 . 8 111 119 93 16 245 510 357 .5 6 . 5 111 119 93 17 135 420 358. 8 13 .4 109 118 92 18 255 440 352 . 3 15.. 0 107 118 91 19 180 365 359 ..5 L41.6 110 118 93 20S 350 280 352 .0 12. 7 106 119 89 Recompacted Harding Lawson Assoclatss SUMMARY OF FIELD DENSITY TEST DATA PLATE Engineers,Geologists HERITAGE AUXILARY BUILDERS &Geophysicists HERITAGE COMMONS, PHASE I DUBLIN, CALIFORNIA DRAWN JOB NUMBER APZED DATE REVISED DATE and 8424 ,002 . 03 9/28/82 00 LL 0- 0 v C a a) u 4 C o_ v [ C 11 i u a n_ Location ° c a Remarks E J� > o a- v v •° a a[ ta i xi o ~ (1) SOUTH EAST (2) w (3) (4) V .21S 390 320 353. 3 12 . 4 109 119 92 22S 395 380 354 . 510 . 7 99 118 84 Retested - See Test No. 25S 23S 370 470 356 .014 . 8 96 118 81 Retested - See Test No. 26S 245 275 475 356 . 511.0 111 118 94 25S 395 380 354 .5 9 . 1 104 118 88 Recompacted 26S 370 470 356 .0 10 . 7 117 118 99 (1) Suffix: S - Denotes Subgrade tests (2) Origin of Coordinates : Northwest property corner . ( 3) Elevation Datum: As shown on Mass Grading Plan by Kinney Engineering, Inc. , undated (4) Maximum Dry Density established in our laboratory in accordance' with the ASTM D1557-78 compaction test method. Harding Lawson Associates SUMMARY OF FIELD DENSITY TEST DATA PLATE Engineers,Geologists HERITAGE AUXILARY BUILDERS &Geophysicists HERITAGE COMMONS, PHASE I 2 DUBLIN, CALIFORNIA DRAWN JOB NUMBER APPR VED DATE REVISED DATE and 8424 ,002 03 9/28/82 Harding Lawson Associates January 18, 1984 8424, 002.03 Heritage Auxilary Builders 2460 Vista Del Monte Concord, California 94520 Attention : Mr. Al Steen Gentlemen: Supplemental Report Soil Engineering Services Heritage Commons , Phase I Dublin, California At your request, we are providing supplemental comments regarding our soil engineering services during site grading for Heritage Commons, Phase I, Dublin, California. The grading was performed during the period between July 28 and August 26, 1982. Recommendations contained in a report by Bay Soils, Incorporated dated January 13, 1981 and the project plans and specifications by Kinney Engineering, Incorporated were the guidelines for the work. Our progress report, dated September 28, 1982, presented a summary of our observations during Phase I grading as well as results of field density testing. In December of 1983 , we were informed that building permits would not be issued for the project because of grading permit requirements for full-time inspection. As stated in our confirming proposal to you dated July 27, 1982, our field services were to be performed on an intermittent basis, which is normal for most grading projects of this magnitude. We do provide full-time inspection when requested or when project conditions dictate. Conditions requiring full-time inspection include most hillside developments or those sites where subdrains, buttress fills, or keyways are specified . None of the conditions were present at the Heritage Commons site which required full-time inspection. The site is generally level with one swale running through the east portion of the site. We were present at the site, as much as we thought necessary, to observe and test the grading operations and our report of September 28, 1982 stated that - Engineers 2430 Stanwell Dr, Telephone Alaska Hawaii Texas Geologists& Suite 110 415/687-9660 California Nevada Washington Geophysicists Concord,CA 94520 January 18, 1984 8424, 002 .03 Harding Lawson Associates Mr . Al Steen Heritage Auxilary Builders Page 2 On the basis of our observations and tests, we conclude that the grading has been completed satisfactorily and in accordance with the project plans and specifications . Our tests indicate that the fills have been compacted to at least 90 percent relative compaction. In our opinion, the fill will provide adequate support for the planned structures . " It is still our opinion that the grading has been completed satisfactorily and in accordance with the project plans and specifications . We trust this provides the information required at this time . If you have questions , please call. Yours very truly, HARDING LAWSONN ASSOCIATES Cecil B. Wood Civil Engineer - 18671 RDP/CBW/ss 3 copies submitted For Group R, Division 1 Occupancies with a Group B, Division 1 parking garage in the basement or first floor, see Section 702(a). For attic space partitions and draft stops, see Section 2516(f). Section 22.9 Section 1204, Chapter 12, Part ill: Exit Facilities on page 90 is amended by adding a new paragraph at the end of the Section to read: to single family dwellings not exceeding two stories in height egress windows from sleeping rooms may be omitted when an additional doorway or an approved exit escape hatch and route to safety is provided for egress from such rooms. The doorways provided shall open directly to the exterior of the building or shall open onto corridors or passageways or areas which lead to individual exterior exits. The separate exiting paths to the individual exterior doorways provided shall not cross nor shall they follow the same route in whole or in part to the building exterior. Approved exit escape hatches shall be installed in accordance with the terms of their approval. Section 22.10 Table 23-A, Chapter 23, Part VI: Uniform and Concentrated Loads. Table 23-A on pages 140 and 141 are amended by adding a new Footnote 9 to read: 9. Bridges for vehicular traffic shall be designed for H2O loading as designated by the American Association of State Highway Officials. Section 22.11 Section 2901, Chapter 29, Part VI: Scope. Section 2901 on page 513 is amended to read: Section 29.10 Scope. 'This chapter sets forth requirements governing grading drainage, mitigation of geo- logic hazards, excavations and fills for any building or structure, and for foundations and retaining struc- tures. Section 22.12 Section 2903, Chapter 29, Part VI: Excavations and Fills. Section 2903 on pages 513 and 514 are amended to read: (a) General. Excavations or fills for any building or structure and excavations or fills accessory thereto shall be so constructed or protected so that they do not endanger life or property. (b) Excavations. Except when permitted under a valid Grading Permit as set forth in Section 115.1 of Chapter 9 of Title 7 of the Alameda County Grading Ordinance as adopted by the City of Dublin, the slope of cut surfaces of permanent excavations shall not be steeper than 2 horizontal to 1 vertical. The slope of cut surfaces shall not be steeper than the bedding planes or principal joint sets in any formation where the cut slope will lie on the dip side of strike line unless the soils and geologic investigations contain recommendations for steeper slopes. Existing footings or foundations which may be affected by any excavation shall be underpinned or otherwise protected against settlement and shall be protected against lateral movement. (c) Fills. The slopes of permanent fills shall not be steeper than 2 horizontal to 1 vertical. The ground surface shall be prepared to receive fill by removing vegetation, fills not placed in accordance with this Ordinance, topsoil and other unsuitable material and where slopes are 5 horizontal to 1 vertical or steeper by benching into sound bedrock or other competent material. Earth materials which have no more than minor amounts of organic substances and have no rock or similar irreducible material with a maximum dimension greater than 6 inches shall be used. Continuous inspection by a special inspector as defined in Section 12.16 shall be required in the following situation. 1. During the preparation of a site for, and the placement of fills which exceed 5 feet in depth on slopes with exceed 10 percent and during the placing of such fills. 2. During the preparation of a site for, and the placement of any fill which will be used to support any building or structure and during the placing of such fills. 3. During the installation of subsurface drainage facilities. All such fills shall be compacted to a minimum of ninety (90) percent of maximum density as determined by UBC Standard 70-1. Field density shall be determined in accordance with UBC Standard 70-2 or equivalent method as approved by the Building Official. f EXCEPTION: Fills supporting slabs where expansive soils are present may be compacted as recommended in the soil and geologic investigation reports. Fills or other surcharge loads shall not be placed adjacent to any building or structure unless such building or structure is capable of withstanding the additional loads caused by such fill or surcharge. (d) Existing Fill. Any fill which exceeds 5 feet in depth on slopes which exceed ten (10) percent and all fills which will be used to support the foundation of any building or structure which existed on August 1, 1974, and which was placed in conformance with the Alameda County Ordinance 950 N.S. effective October 1, 1965, need not have continuous inspection. All other fills which exceed 5 feet in depth on slopes which exceed ten (10) percent and all fills which will be used to support the foundation of any building or structure, which existed on August 1, 1974, shall be altered or completely removed and replaced so as to conform to Section 2903(c). Any fill placed after August 1, 1974 which exceeds 5 feet in depth on slopes which exceed ten (10) percent or which will be used to support the foundation of any building or structure without continuous inspection by a special inspector, shall be altered or completely removed and replaced so as to conform to Section 2903(c). (e) Erosion Control. The faces of cut and fill slopes shall be prepared and maintained to control against erosion. This control may consist of effective planting. The protection of the slopes shall be installed as soon as practicable and prior to calling for final inspection and approval. Approval of occupancy may be withheld by the Building Official until such protection has been installed. Where cut slopes are not subject to erosion due to the erosion resistant character of the materials, such protection may be omitted. (f) Setback. Unless otherwise recommended in a soil and geologic investigation report set forth in Section 2903, Table 70-C on page 736 shall be used for establishing setbacks for buildings and structures other than fences and retaining walls from the top or toe of permanent cut or fill slopes. (g) Protection of Adjoining Property. The rights of coterminous owners shall be as set forth in Section 832 of the Civil Code of the State of California. Section 22.13 Section 2905, Chapter 29, Part Vi: Foundation Investigation. Section 2905 on pages 514 and 515 is amended to read: Section 2905 Soil and Geologic Investigation. (a) When Required. A soil and/or geologic investigation shall be required in the following circumstances. 1. For all A-1, A-2, A-2.1 and H-1 Occupancies. A soil investigation shall not be required for additions to existing dwellings unless conditions cited in Items 2 through 11 exists. EXCEPTION: A soil investigation shall not be required for M Occupancies. 2. When the allowable soil pressure used in the design of the foundation exceeds 2,000 psf. 3. When the building is proposed to be supported in fill. 4. When the slope of the natural ground within 30 feet of any building or structure exceeds twenty (20) percent and the slope is more than 10 feet in height. 5. When a cut or a fill exceeding 5 feet in depth at any point either exists or is proposed and the slope of the natural ground within 30 feet of the building or the cut or fill exceeds ten (10) percent and the slope is more than 10 feet in height. 6. Where highly expansive or erodible soils are present unless it can be demonstrated to the satisfaction of the Building Official that the structure will not bear on such soils, or that the recommendations of a soil engineer are suitable. 7. When required under Section 7100(c), Vehicular Access. 8. In any subdivision into five or more parcels as defined in Section 8-1.3 of the Alameda County Ordinance Code as adopted by the City of Dublin which has been recorded after September 17, 1965. Where highly expansive soils or other soil conditions are present within a subdivision, which if not corrected would lead to structural defects, a soil and/or geologic investigation report shall be required for each lot in the subdivision. 9. On a building site traversed or suspected to be traversed by a potentially active fault. -22- . ' .' RESOLUTION NO. A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF DUBLIN ------------------------------------- GRANT VARIANCE REGARDING HERITAGE COMMONS PHASE I WHEREAS, Heritage Auxiliary Builders, 222 Seventh Street, San Francisco, California, 94103, has requested a Variance to Section 2903 (c ) of the Building Code, so as to waive the requirements for full time, continuous inspection of the placement of the fill in the Heritage Commons Development (TRACT 4950 ) ; and WHEREAS, the placement of the fill was provided intermittent inspection by Harding Lawson Associates ; and WHEREAS, Harding Lawson and Associates states : "On the basis of our observations and tests , we conclude that the grading has been completed satisfactorily and in accordance with the project plans and specifications . Our tests indicate that the fills have been compacted to at least 90 percent relative compaction . In our opinion, the fill will provide adequate support for the planned structures . " WHEREAS, this specific site is relatively flat and the maximum depth of the fill is approximately ten feet; and WHEREAS, this City Council finds that granting the Variance is consistant with the intent of the code, and it will not lessen the protection to the people of the City of Dublin and the property situated therein; NOW THEREFORE BE IT RESOLVED that the Heritage Auxiliary Builders are hereby granted a Variance to Section 2903 (c ) of the Building Code subject to the condition that owners of said property execute and record a hold harmless agreement, holding the City of Dublin, its officers, employees and contractors harmless from any damages that may result from the granting of this Variance . The form as said hold harmless agreement shall be subject to the approval of the City Attorney. PASSED, APPROVED AND ADOPTED this th day of AYES: NOES: ABSENT: Mayor ATTEST: .'t City Clerk