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HomeMy WebLinkAboutParcel Map 7555 Parcel 3 Certification of Rough Lines & Grades Ie . '!.5 ~~"'S" 1>"" 3 W. C. HOBBS, CONSULTING ENGINEER 29284 OLD WRANGLER ROAD CANYON LAKE, CALIFORNIA 92587 (909) 244-5177 Date: April 29, 1998 'Mr. Johnston 140112 Zamura Ct. 'Murrieta, California 92562 :Subject: Certification of Rough Lines and Grades,:!: 0.1 feet Building Pad and Driveway Grading, Parcel 3 of PM 7555 Wolcatt Lane, City of Temecula, California IAttention: Building Official : Dear Mr. Johnston, : Pursuant to your request, this letter has been prepared to document that the site has been ;graded in substantial conformance to the indicated lines and grades on the approved ,grading plans. The pad has been graded to the elevation indicated on the grading plan :of 1255.0 and is 1: one tenth of a foot. Slopes have been graded at 2:1 ratios and drainage is in accordance with city ordinance specifications. In the event of any additional grading to be performed in the future, the property owner should only do so with plans approved :by the City of Temecula. It is my Professional opinion that rough grading should be 'approved and building permits issued. IThe opportunity to be of service is appreciated. Should questions or comments arise pertaining to this document, please contact the undersigned, in writing, for clarification. Respectfully Submitted, \ I. . " w. C. HOBBS, CONSULTING ENGINEER 29284 OLD WRANGLER ROAD CANYON LAKE, CALIFORNIA 92587 (909) 244-5177 Project No: 98027-1 Date: April 29, 1998 , Mr. and Mrs. Johnston : 40112 Zumara Ct , Murrieta, California 92562 : Subject: Results of Compaction Testing During Rough Grading, Parcel 3 of PM 7555, Walcott Lane, Temecula, Riverside County, California : Dear Mr. Johnston, : Contained herein are the results of compaction testing and observations made during rough grade : operations for the house pad area at the subject site. The location of the tests are plotted on a ,portion of the grading plan and the test results are contained in the attached Appendix A 'It should be noted that observation and testing for the pad and drive areas was performed on a :periodic basis, and portions of the information relative to procedures used was provided by the ,grading contractor and by direct observation. IThis observation and testing was performed in accordance with generally accepted engineering :practioes. The conclusions and recommendations contained in this report were based on the data ,available and the interpretation of such data as dictated by our experience and background. Hence, our conclusions and recommendations are professional opinions; therefore, no other 'warranty is offered or implied. :Accompanying Illustrations and Appendices :Test Location Map, Plate 1 :Appendix A, Summary of Field Density and Laboratory Test Results z. I. . 'Mr. Johnston, Walcott Ln., Temecula 'Project No: 98027-1 Page: 2 Summary of Earthwork ;GeneraI :Site grading was conducted during the month of April, 1998, by PDQ Equipment of Temecula, :Califomia. I Rough Grading 'Areas to receive fill or to be processed were first stripped of vegetation that was disposed of : properly on the site or otherwise removed from the site. The ground to receive fill was scarified to : a .depth of 12 inches, brought to near optimum moisture content and compacted to the minimum 'requirements prior to the placement of fill. 'Fill was placed in 12-inch loose lifts, brought to a uniform near optimum moisture content and : compacted to a minimum of 90 percent relative compaction. This is relative to the maximum dry : density as determined in accordance with ASTM test designation 0 1557-78. : Grading was accomplished with the use of a D-8 size Dozer and Water Truck. Water was added ,when necessary with the use of a water truck drawing from a meter. Compaction was achieved by . repeated passes of the heavy equipment over each lift of fill. 'A-key was excavated a minimum of 2 feet into competent earth materials, approximately 2 to 5 feet : below existing ground surface, at the toe of proposed slopes. Benching into firm materials was :accomplished as the fill progressed up the gently sloping ground so that all fill materials were : placed onto competent earth. The area of the "Arizona" crossing was over excavated ,approximately 2 feet to provide firm embedment for the culverts. CONCLUSIONS AND RECOMMENDATIONS I CONCLUSIONS '(1) Test results indicate that fill placed as a result of this grading, to the horizontal and vertical limits : as indicated, has been compacted to at least 90 percent relative compaction. A total of 9 tests ,were conducted and the results are tabulated at the back of this report. The approximate locations : of the field density tests are indicated on the Test Location Plan, Plate 1. . (2) Fill Materials consisted of onsite silty sand and sand. . (3) Based on observation and classification, the matrix soils on the pad area appear to have an : expansion potential of low to very low. W. C. HOBBS. CONSULTING ENGINEER 3 I. . 'Mr. Johnston, Walcott Ln., Temecula :Project No: 98027-1 Page: 3 (4) GroundlNaterwas not encountered in any of the excavations during rough grading operations. (5) preparation of the driveway surface combined with compaction and an overlay of decomposed ;granitics should provide adequate support for emergency vehicles with up to 30,000 gvw. :RECOMMENDATlONS IThe recommendations contained herein are contingent upon W. C. Hobbs being retained to :provide the following services in order to confirm design assumptions and review the field :conditions of any excavations. :Bearing Value and Footing Geometry !Asafe allowable bearing value for foundations embedded a minimum of 12 inches below lowest iadjacent grade into competent native ground or compacted fill ground is 1500 pst. These values may be increased 100 pst per foot of depth and or width and should not exceed 2000 pst. :Continuous footings should have a minimum width of 12 inches. The use of isolated column lfootings is permitted, and where utilized, should have a minimum embedment of 12 inches below : lowest soil grade. Interior column footings need not be tied to perimeter footings, but should meet Ithe minimum embedment criteria of 12". Minimum cover to daylight at slope face is 8 feet. :Settlement IThe bearing value recommended above reflects a total settlement of 0.5" and a differential ,settlement of 0.5". This settlement is expected to occur during construction and as the loads are :being applied. Where foundations are embedded into native ground, settlements can be isubstantially less. :Concrete Slabs :AII concrete slabs on grade should be at least 4 inches thick. They should be underlain by 2 inches of sand or,gravel. Areas that are to be carpeted or tiled, or where the intrusion of moisture !is:objectionable, should be underlain by 6 mil visqueen properly protected from puncture with an iadditional1 inch of sand over it. This arrangement of materials would result in a profile downward of concrete, 1 inch of sand, 6 mil visqueen, 1 inch of sand and subgrade soil. Driveway slabs will not require underlayments. Contractors should be advise that when pouring during hot or windy weather conditions, they should provide large slabs with sufficiently deep weakened plane joints to inhibit the development of unsightly and irregular cracks. Clean onsite earth materials such as sand may be used for slab underlayments. W. C. HOBBS. CONSULTING ENGINEER 4. I. . 'Mr. Johnston, Walcott Ln., Temecula :Project No: 98027-1 Page: 4 I Reconvnendations, continued I Reinforcement : Continuous footings should be reinforced with a minimum of one number 4 steel bar placed at the top and one at the bottom. Slabs should be reinforced with a minimum of number 3 steel bars :p1aced at the center of thickness at 18-inch centers both ways or welded wire fabric equivalent to '1 Ox1 0, 616 may be used. Selection is left to the Structural Engineer or Contractor. ,Lateral Loads iThe bearing value of the soil may be increased by one third for short duration loading (wind, 'seismic). Lateral loads may be resisted by passive forces developed along the sides of concrete 'footings or by friction along the bottom of concrete footings. The value of the passive resistance may be CXlmputed using an equivalent fluid density of 250 pcf. The total force should not exceed ;2500 pst. A coefficient of friction of 0.35 may be used for the horizontal soil/concrete interface for resistance of lateral forces. If friction and passive forces are combined, then the passive values :should be reduced by one third. A safety factor of 1.5 should be used in design. :Retaining Walls Hetaining walls should be designed to resist the active pressures summarized in the following ,table. The active pressure is normally calculated from the lowermost portion of the footing to the 'highest ground surface at the back of the wall. The active pressures indicated in the table are :equivalent fluid densities. Walls that are not free to rotate or that are braced at the top should use 'active pressures that are 50% greater than those indicated in the table. RETAINING WALL DESIGN PRESSURES Slope of adiacent ground Active Pressure Passive Pressure LEVEL(<5:1) 2:1 30pcf 38pcf 450 pcf 250 pcf !These pressures are for retaining walls backfilled with non-cohesive, granular materials and provided with drainage devices such as weep holes or subdrains to prevent the build-up of 'hydrostatic pressures beyond the design values. w. C. HOBBS, CONSULTING ENGINEER -s I. . 'Mr. Johnston, Walcott Ln., Temecula : Project No: 98027-1 Page: 5 I Recommendations, continued I Fine Grading ; Fine grading of areas outside of the residence should be accomplished such that positive drainage 'exists away from all footings. RUrHlff should be conducted off the property in a non-erosive 'manner toward approved drainage devices. I Construction : Backfilling of any retaining walls should be observed by a soil engineer to assist the contractor in : achieving the proper degree of compaction and desired moisture content. Also, the retaining wall , subdrain system should be observed by the engineer prior to the backfill being placed. It is advisable to tlave the foundation excavations observed by a soil engineer prior the placement ,of construction materials in them as consequential changes and differences may exist throughout the fill and natural soils on the site. The ground left:at the surface has very high erosion potential. It is strongly recommended that I irrigation and vegetation or other approved means of erosion control be placed as soon as practical to minimize damage due to erosion. : The opportunity to be of service is appreciated. Should questions or comments arise pertaining to ,this document, please contact the undersigned, in writing, for clarification. Respectfully Submitted, ,w. C. HOBBS, CONSUL T1NG ENGINEER Bill Hobbs, RCE42265 :Civil Engineer :Distribution: Addressee (4) ~Attachments: Appendix A, Plate 1 w. C. HOBBS, CONSULTING ENGINEER ~ I. . APPENDIX A SUMMARY OF RELD DENSITY TESTS Test Date Location Elev.* Typ Max M.C. Dry Rei Comments Num. ,of Test of Test (feet) Crv D.O. (Qg) Dens. Com Remarks 1 :4198 PAD AREA 1245 A 131.5 13.0 119.0 90% Fill 2 :4198 PAD AREA 1247 A 131.5 12.5 118.5 90% Fill 3 :4198 PAD AREA 1248 A 131.5 11.5 124.5 95% Fill 4 :4198 PAD AREA 1249 A 131.5 11.5 118.0 90% Fill 5 :4198 PAD AREA 1251 A 131.5 10.0 119.5 91% Fill 6 :4/98 PAD AREA 1253 A 131.5 10.0 122.5 93% Fill 7 :4198 PAD AREA 1255.Ofp A 131.5 9.0 123.0 93% Fill 8 :4/98 PAD AREA 1255 A 131.5 10.0 122.5 93% Fill 9 :4198 DRIVE AREA 1208.5 A 131.5 9.0 119.0 90% Fill Field Density Tests were conducted in accordance with ASTM 02937 fp denotes finished pad. * Below current pad elevation SUMMARY OF LABORATORY TEST RESULTS Curve Letter Soil Description Maximum Optimum Density pd Moisture % A Silty, SAND fn to med., Brown(SM) 131.5 10.0 Maximum density and optimum moisture determined in accordance with test method ASTM 0 1557-78. w. C. 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