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CT 05-01; CRESCENT DEL SOL ESTATES; GRADING PLAN REVIEW; 2006-02-27
Cl- M- Of, COAST GEOTECHNICAL CONSULTING ENGINEERS AND GEOLOGISTS February 27, 2006 Wayne Blass and Mark Petersen 6965 El Camino Real, Suite 105 Carlsbad , CA 92009-4195 Subject: GRADING PLAN REVIEW Crescent Del Sol Estates 234/236 Date Avenue Carlsbad, California References: Please see page 3 Dear Mr. Blass and Mr. Petersen: Our review of the proposed grading plans prepared by BHA, Civil Engineering, Sheets 3 and 4, suggests that they have, in general, included the applicable recommendations presented in our Preliminary Geotechnical Investigation and supplemental reports. COMMENTS Temporary cut slopes should be observed by an Engineering Geologist or Geotechnical Engineer. Additional recommendations may be necessary. Densification of the subgrade deposits exposed along the basement excavation will be required. Additional. recommendations will be necessary during the grading phase, in this regard. 779 ACADEMY DRWE • SOLANA BEACH, CALIFORNIA 92075 (858) 755-8622 • FAX (858)755-9126 Coast Geotechnical February 27, 2006 W.O. P-400123 Page 2 LIMITATIONS The findings and opinions presented herein have been made in acco r d a n c e w i t h g e n e r a l l y a c c e p t e d professional principals in the fields of engineering geology and s o i l s e n g i n e e r i n g . N o w a r r a n t y i s provided. If you have any questions regarding this report, please contact our o f f i c e . R e f e r e n c e t o o u r J o b N o . P-400123 will help expedite a response to your inquiry. . Respectfully submitted, COAST GEOTECHNICAL Mark Burwell, C.E.G. Vithaya Singhanet, P.E. Engineering Geologist . Geotechnical Engineer Coast Geotechnical February 16, 2006 W.O. P-400123 Page 3 REFERENCES PRELIMINARY GEOTECHNICAL INVESTIGATION Proposed Eleven (11) Unit Condominium 236 Date Avenue Carlsbad, California Prepared by Coast Geotechnical Dated February 4, 2004 GEOTECHNICAL REVIEW OF PROPOSED DEVELOPMENT Eight (8) Single Family Residences 236 Date Avenue Carlsbad, California Prepared by Coast Geotechnical Dated April 4, 2005 SUPPLEMENTAL GEOTECHNICAL INVESTIGATION Proposed Eleven (11) Unit Condominium 236 Date Avenue Carlsbad, California Prepared by Coast Geotechnical Dated September 28, 2005 REVISED FOUNDATION DESIGN PARAMETERS Crescent Del Sol Estates 234/236 Date Avenue Carlsbad, California Prepared by Coast Geotechnical Dated January 11, 2006 GEOTECHNICAL UPDATE LETTER - PLAN CHECK NO. 06-0163 Crescent Del Sol Estates 234/236 Date Avenue Carlsbad, California Prepared by Coast Geotechnical Dated February 16, 2006 Coast Geotechnical February 16, 2006 W.O. P-400123 Page 4 6) FOUNDATION PLAN REVIEW - PLAN CHECK NO. 06-0163 Crescent Del So! Estates 234/236 Date Avenue Carlsbad, California Prepared by Coast Geotechnical Dated February 16, 2006 COAST GEOTECHNICAL CONSULTING ENGINEERS AND GEOLOGISTS February 16, 2006 Wayne Blass and Mark Petersen 6965 El Carnino Real, Suite 105 Carlsbad, CA 92009-4195 RE:. FOUNDATION PLAN REVIEW - PLAN CHECK NO. 06-0163 Crescent Del Sol Estates 234/236 Date Avenue Carlsbad, California References: 1) PRELIMINARY GEOTECHNICAL INVESTIGATION Proposed Eleven (11) Unit Condominium 236 Date Avenue Carlsbad, California Prepared by Coast Geotechnical Dated February 4, 2004 GEOTECHNICAL REVIEW OF PROPOSED DEVELOPMENT Eight (8). Single Family Residences 236 Date Avenue Carlsbad, California Prepared by Coast Geotechnical Dated April 4, 2005 0 SUPPLEMENTAL GEOTECHNICAL INVESTIGATION Proposed Eleven (11) Unit Condominium 236 Date Avenue Carlsbad, California Prepared by Coast Geotechnical Dated September 28, 2005 REVISED FOUNDATION DESIGN PARAMETERS Crescent Del Sol Estates 234/236 Date Avenue Carlsbad, California Prepared by Coast Geotechnical Dated January 11, 2006 779 ACADEMY DRIVE • SOLANA BEACH, CALIFORNIA 92075 (858) 755-8622 0 FAX (858) 755-9126 Coast Geotechnical February 16, 2006 W.O. P-400123 Page 2 Dear Mr. Blass and Mr. Petersen: As requested, we have reviewed the project foundation plans, Sheets S2.1 and D e t a i l S h e e t S 4 - 1 , dated February 6, 2006, prepared by Thornton-Tomasetti Group, and observed th a t t h e y h a v e , i n general, included the recommendations presented in our Preliminary Geotechnical In v e s t i g a t i o n a n d our Revised Foundation Design Parameters Report, (Job No. P-417054). COMMENTS All footing excavations should be observed by a geotechnical engineer or e n g i n e e r i n g geologist, prior to placement of steel. Fill placed on top of deepened column pads should be compacted to a minimum of 90 percent of the laboratory maximum dry density. All fill should be observed and tested by a representative of this firm. LIMITATIONS The findings and opinions presented herein have been made in accordance wit h g e n e r a l l y a c c e p t e d professional principals in the fields of engineering geology and geotechnical en g i n e e r i n g . N o warranty is expressed or implied. Coast Geotechnical February 16, 2006 W.O. P-400123 Page 3 If you have any questions regarding this report, please contact our offic e . R e f e r e n c e t o o u r J o b N o . P-400123 will help expedite a response to your inquiry. Respectfully submitted, COAST GEOTECHNICAL Mark Burwell, C.E.G. Vithaya Singhanet, P.E. Engineering Geologist Geotechnical Engineer COAST GEOTECHNICAL CONSULTING ENGINEERS AND GEOLOGISTS February 16, 2006 Wayne Blass and Mark Petersen 6965 El Camino Real, Suite 105 Carlsbad, CA 92009-4195 RE: GEOTECHNICAL UPDATE LETTER - PLAN CHECK NO. 06-0163 Crescent Del Sol Estates 234/236 Date Avenue Carlsbad, California References: 1) PRELIMINARY GEOTECHNICAL INVESTIGATION Proposed Eleven (11) Unit Condominium 236 Date Avenue Carlsbad, California Prepared by Coast Geotechnical Dated February 4, 2004 GEOTECHNICAL REVIEW OF PROPOSED DEVELOPMENT Eight (8) Single Family Residences 236 Date Avenue Carlsbad, California Prepared by Coast Geotechnical Dated April 4, 2005 SUPPLEMENTAL GEOTECHNICAL INVESTIGATION Proposed Eleven (11) Unit Condominium 236 Date Avenue Carlsbad, California Prepared by Coast Geotechnical Dated September* 28, 2005 REVISED FOUNDATION DESIGN PARAMETERS Crescent Del Sol Estates 234/236 Date Avenue Carlsbad, California Prepared by Coast Geotechnical • Dated January 11, 2006 779 ACADEMY DRIVE • SOLANA BEACH, CALIFORNIA 92075 (858) 755-8622 • FAX (858) 755-9126 Coast Geotechnical February 16, 2006 W.O. P-400123 Page 2 Dear Mr. Blass and Mr. Petersen: In response to your request, we have performed a geotechnical update on t h e a b o v e r e f e r e n c e d property. The purpose of the update is to evaluate if any s i g n i f i c a n t c h a n g e s t o t h e p r o p e r t y h a v e occurred since the completion of our Preliminary Geote c h n i c a l S t u d y . Based on a site review on February 16, 2006, no discernibl e c h a n g e s i n t h e g e o t e c h n i c a l c o n d i t i o n s have occurred on the property since our Preliminary Geot e c h n i c a l I n v e s t i g a t i o n o n F e b r u a r y 4 , 2 0 0 4 and 'our Supplemental Geotechnical Investigation on Septe m b e r 2 8 , 2 0 0 5 . The conclusions and recommendations presented in the refer e n c e d r e p o r t s r e m a i n v a l i d a n d s h o u l d be implemented in the final design and construction phas e s . If you have any questions, please-do not hesitate to contact us at (858) 755-8622. This opportunity to be of service is appreciated. Respectfully submitted, COAST GEOTECHNICAL Mark Burwell, C.E.O. Vithaya Singhanet, P.E. Engineering Geologist' ' ' Geotechnical Engineer COAST GEOTECHNICAL CONSULTING ENGINEERS AND GEOLOGISTS January 11, 2006 Mark Petersen and Wayne Blass 185 Phoebe Street Encinitas , CA 92024 RE: REVISED FOUNDATION DESIGN PARAMETERS Crescent Del Sol Estates 234/236 Date Avenue Carlsbad, California References: 1) PRELIMINARY GEOTECHNICAL INVESTIGATION Proposed Eleven (11) Unit Condominium 236 Date Avenue Carlsbad, California Prepared by Coast Geotechnical Dated February 4, 2004 2) SUPPLEMENTAL GEOTECHNICAL INVESTIGATION Proposed Eleven (11) Unit Condominium 236 Date Avenue Carlsbad, California Prepared by Coast Geotechnical Dated September 28, 2005 Dear Mr. Petersen and Mr. Blass: In response to your request, we have reviewed our foundation design parameters presented in ou r Preliminary Geotechnical Investigation, as well as the current foundation plans, dated Decem b e r 1 6 , 2005, prepared by the Thornton-Tomasetti Group. 779 ACADEMY DRIVE • SOLANA BEACH, CALIFORNIA 92075 (858) 755-8622 • FAX (858) 755-9126 Coast Geotechnical January 11, 2006 W.O. P-400123 Page 2 FOUNDATION PLANS The foundation plans suggest that the proposed structures will be s u p p o r t e d p r e d o m i n a n t l y o n subterranean retaining walls and isolated column pads constructed at t h e g a r a g e b a s e m e n t g r a d e . A 4.0 inch thick reinforced slab is proposed for the subterranean ga r a g e f l o o r . GEOTECHNICAL CONDITIONS The subject property is underlain by poorly consolidated Pleistocene t e r r a c e d e p o s i t s . T h e f i n e a n d medium-grained sand is friable on exposed cuts with little or no co h e s i o n . S u b s u r f a c e e x p l o r a t i o n suggests that the sediments are only in a medium dense condition at t h e g a r a g e b a s e m e n t e l e v a t i o n . The density of the fine and medium-grained deposits may be increased b y s e l e c t i v e r e m e d i a l g r a d i n g and moisture conditioning in the upper 2.0 feet of subgrade deposits. S p e c i f i c r e c o m m e n d a t i o n s f o r densification will be provided during the grading phase based on act u a l g e o t e c h n i c a l c o n d i t i o n s encountered in the garage excavation. REVISED FOUNDATION DESIGN PARAMETERS The following design parameters are based on footings founded into d e n s i f i e d t e r r a c e d e p o s i t s exposed at the garage excavation elevation. - Proposed retaining wall footings, column pad footings and continuo u s w a l l f o o t i n g s f o u n d e d a - minimum of 18 inches into terrace deposits may be designed for an allo w a b l e b e a r i n g v a l u e o f 2 2 5 0 pounds per square foot. The bearing value may be increased 300 p o u n d s p e r s q u a r e f o o t f o r e a c h additional foot of depth of terrace deposits penetrated to a maximum of 300 0 p o u n d s p e r s q u a r e f o o t . Coast Geotechnical January 11, 2006 W.O. P-400123 Page 3 The design parameters presented in the Preliminary Geotechnical Rep o r t w h i c h a r e n o t s u p e r c e d e d by this report remain applicable and should be implemented during t h e d e s i g n a n d c o n s t r u c t i o n phases. S If you have any questions, please do not hesitate to contact us at (858) 7 5 5 - 8 6 2 2 . T h i s o p p o r t u n i t y to be of service is appreciated. Respectfully submitted, COAST GEOTECHNICAL Mark Burwell, C.E.G. Vithaya Singhanet, P.E. Engineering Geologist Geotechnical Engineer COAST GEOTECHNICAL CONSULTING ENGINEERS AND GEOLOGISTS September 28, 2005 Mark Petersen and Wayne Blass 185 Phoebe Street Encinitas , CA 92.024 RE: SUPPLEMENTAL GEOTECHNICAL INVESTIGATION Proposed Eleven (11) Unit Condominium 236 Date Avenue Carlsbad, California Reference: PRELIMINARY GEOTECHNICAL INVESTIGATION Proposed Eleven (11) Unit Condominium 236 Date Avenue S Carlsbad, California Prepared by Coast Geotechnical Dated February 4, 2004 Dear. Mr. Petersen and Mr. Blass: This report is in response to the city of Carlsbad concern, "At the design stage of the gradi n g , t h e soils engineer will need to address the underground garage excavation and how it could affec t t h e existing neighboring structures." In order to evaluate if any fluctuations in groundwater levels or other geotechnical conditions have changed since our Preliminary. Geotechnical Investigation, one (1) exploratory boring was drilled to a depth of 20 feet with a hollow-stem drill rig in the northwestern portion of the site. 779 ACADEMY DRIVE • SOLANA BEACH, CALIFORNIA 92075 (858) 755-8622 • FAX (858) 755-9126 Coast Geotechnical September 28, 2005 W.O. P-400123 Page 2 GEOTECHNICAL CONDITIONS The subject property is underlain at relatively shallow depths by p o o r l y c o n s o l i d a t e d P l e i s t o c e n e terrace deposits. The terrace deposits are composed of fine and mediu m - g r a i n e d s a n d i n a m e d i u m dense condition. Our supplemental exploratory boring suggests that no hi g h g r o u n d w a t e r c o n d i t i o n s or perched water tables. have developed from the recent record rainf a l l t o t h e d e p t h e x p l o r e d . However, it should be noted that the Pleistocene sands are very we a k l y c e m e n t e d a n d h a v e l i t t l e o r no cohesion. These characteristics suggest that the terrace deposits are f r i a b l e o n e x p o s e d c u t s l o p e s . LABORATORY TESTING, Classification The field classification was verified through laboratory examination, i n a c c o r d a n c e w i t h t h e U n i f i e d Soil Classification System. The final classification is shown on the en c l o s e d E x p l o r a t o r y L o g . Moisture/Density The, field moisture content and dry unit weight were determined f o r e a c h o f t h e u n d i s t u r b e d s o i l samples. This information is useful in providing a gross picture of the s o i l c o n s i s t e n c y o r v a r i a t i o n among exploratory excavations. The dry unit weight was determined i n p o u n d s p e r c u b i c f o o t . T h e field moisture content was determined as a percentage of the dry un i t w e i g h t . B o t h a r e s h o w n o n the enclosed Laboratory Tests Results and Exploratory Log. Coast Geotechnical September 28, 2005 W.O. P-400123 - Page Shear Test Shear tests were performed in a strain-control type direct shear mach i n e . T h e r a t e o f d e f o r m a t i o n was approximately 0.025 inches per minute. Each sample was she a r e d u n d e r v a r y i n g c o n f i n i n g l o a d s in order to determine the Coulomb shear strength parameters, cohesi o n a n d a n g l e o f i n t e r n a l f r i c t i o n . Samples were tested in a saturated condition. The results are pr e s e n t e d i n t h e L a b o r a t o r y T e s t Results CONCLUSIONS No adverse geologic conditions were encountered in our supplemental e x p l o r a t o r y b o r i n g . S t a b i l i t y analysis suggests that temporary slopes graded at an inclination o f 3/4: 1 (horizontal to vertical) are grossly stable for construction purposes. However, the Pleistocen e s a n d s a r e f r i a b l e a n d a s t h e exposed sands dry out, sloughing along the slope face will occur. The results of this study and the referenced geotechnical investi g a t i o n s u g g e s t t h a t t e m p o r a r y c u t s for the garage excavation constructed at a gradient of 3/4: 1 (horizontal to vertical), or less, will not adversely affect the existing neighboring structures. As with all exca v a t i o n s , a C e r t i f i e d E n g i n e e r i n g Geologist should review all temporary cut slopes. • Coast Geotechnical September28, 2005 W.O. P-400123 Page LIMITATIONS The findings and opinions presented herein have been made in accordance w i t h g e n e r a l l y a c c e p t e d professional principals in the fields of engineering geology and soils enginee r i n g . N o w a r r a n t y i s provided. If you have any questions regarding this report, please contact our office. Ref e r e n c e t o o u r J o b N o . P-400123 will help expedite a response to your inquiry. Respectfully submitted, COAST GEOTECHNICAL Mark Burwell, C.E.G. Vithaya Singhanet, P.E. Engineering Geologist Geotechnical Engineer Enclosures: Laboratory Test Results Boring Log Slope Stability Analysis Cross Section A-A' Cross Section B-B' • Site Plan ENCLOSURES LABORATORY TEST RESULTS Sample Location B-i @ 4.0' B-i @ 5.0' B-i @ 8.0' B-i @ 9.0' B-i @ 12.0' B-i @ 13.0' B-i @ 16.0' B-i .@ 17.0' B-i © 19.0' TABLE I Field Dry Density and Moisture Content Field Dry Field Moisture Density Content (pcf) 108.1 .9.5 SPT 9.2 110.7 6.0 SPT 5.9 109.7 6.9 SPT •' 5.5 93.2 5.8 SPT 6.2 SPT • 6.8 Sample Location B-i © 12.0' (Ring) TABLE II Direct Shear Test Results Angle of Internal Friction 0 75 Degrees Apparent Cohesion (psf) 36 P-400i23 L LOG OF EXPLORATORY BORING NO. 1 DRILL RIG: PORTABLE HOLLOW-STEM AUGER PROJECT NO. P-400123 BORING DIAMETER: 6.0" DATE DRILLED: 09-14-05 SURFACE ELEV.: 45.4' (Approximate). . LOGGED BY: MB STANDARD PENETRATION TEST 140 POUND HAMMER, 30 INCH DROP . 1 •1 z ,. . e. U U . GEOLOGIC DESCRIPTION 45.40 ______ = 0.00 SM SOIL(Qs): Brown fine and medium-grained sand, slightly silty = 434( 2.00 J SP TERRACE DEPOSITS (Qt): Tan to Reddish brn., fine and med.-graine 108.1 9.5 SPT 9.2 16 a) Cl) -o 0 a) 110.7 6.0 SPT 5.9 16 0 z 109.7 6.9 SPT 5.5 .. . 22 93.2 5.8 SPT 6.2 28 SPT 6.8 48 PAGE lOFI 7 From 16', Grades ot whitish grey fine and med.-grained sand 27 18 End of Boring @ 20' COAST GEOTECHNICAL PETERSON P-400123 Temporary Slope Analysis 60 C:\STEDWIN\-NEWFILE.PL2 Run By: MB/VS 9!2712005 2:53PM # FS Soil Soil Total Saturated Cohesion Friction Piez. a 1.34 Desc. Type Unit Wt. Unit Wt. Intercept Angle Surface b 1.35 No. (pcf) (pci) (psi) (deg) No. c 1.35 Qt 1 109.7 120.0 75.0 36.0 0 dl.35 e 1.36 50 fl.37. . g1.38 er hl.38 i 1.41 il.44 40 30 20 10 0' 0 GS7ABLT• 10 20 30 40 50 . 60 70 80 90 GSTABL7 v.2 FSmin=1.34 Safety Factors Are Calculated By The Modified Bishop Method EXIST. WALL PROPOSED WALL SOIL • 7....--------------- -; - - - ... TERRACE DEPOSITS I . . - I! BASEMENT I' STAIRS 3/4:1 TEMP. SLOPE • •• I II S CROSS SECTION A-A' (SHOWING GENERAL SUBSURFACE CONDITIONS) SCALE 1"=5' -35' COAST GEOTEC}-tNICAL - S S P-400123 -456 \ . . TERRACE DEPOSITS. \ 3/41 TEMPORARY SLOPE BASEMENT -3-3: CROSS SECTION B-B' (SHOWING GENERAL SUBSURFACE CONDITIONS) SCALE 1"=5' . COAST GEOTECHNICAL P.400123 \ K 44.4 OOT oly 0 48.7 46.2 V X47.9 \ K APN 'O8—b8O-4 47.0 x x sg . X 44.5 \\ \\\ c.... 0 X47 x . X47. /4 K \ 47. S * • .1 . ... .. • 0 \. . x\ . . N5 .. 41 . K .•, - \ 4 K47 47.7 45 145 ..S / 6 6 8 K c' 494 6 50.1 SITE PLAN SCALE: 1"=40' N LEGEND S K \\ CROSS SECTION oe OA N COAST GEOThCCAL S P400123 COAST GEOTECHNICAL CONSULTING ENGINEERS AND GEOLOGIS T S April 4, 2005 Mark Petersen 185 Phoebe Street Encinitas, CA 92024 RE: GEOTECHNICAL REVIEW OF PROPOSED DEVE L O P M E N T Eight (8) Single Family Residences 236 Date Avenue Carlsbad, California Reference: PRELIMINARY GEOTECHNICAL IN V E S T I G A T I O N Proposed Eleven (11) Unit Condominium 236 Date Avenue Carlsbad, California Prepared by Coast Geotechnical Dated February 4, 2004 Dear Mr. Petersen: In response to your request, we have reviewed the pre l i m i n a r y p l a n s p r e p a r e d b y T r a n s p a c i f i c Architects. The purpose of this update is to evaluate the c u r r e n t p r o j e c t c o n c e p t i n r e l a t i o n t o t h e previously completed Preliminary Geotechnical Inves t i g a t i o n . P l a n s w e r e u n a v a i l a b l e a t t h e t i m e of our preliminary study. Current plans indicate that eight (8) single family re s i d e n c e s w i l l b e c o n s t r u c t e d o n t h e p r o p e r t y . Two (2) of the structures will be a twin home design. H o w e v e r , a l l o f t h e r e s i d e n c e s w i l l b e a t w o 779 ACADEMY DRIVE • SOLANA BEACH, CALIFORNIA 92075 (858) 755-8622 • FAX (858) 755-9126 Coast Geotechnical April 4, 2005 W.O. P-400123 Page 2 story design constructed over a subterranean garage. Excavations of approximately 11 V e r t i c a l f e e t are proposed for subterranean garage construction. The current preliminary plans for the development of the site are in general conforman c e w i t h t h e project concept anticipated in our preliminary study. The conclusions and recommendations o f t h e Preliminary Geotechnical Investigation remain applicable and should be implemente d d u r i n g t h e design ad construction phases. LIMITATIONS The findings and opinions presented herein have been made in accordance with genera l l y a c c e p t e d professional principals in the fields of engineering geology and geotechnical engineerin g . N o warranty is expressed or implied. If you have any questions regarding this report, please contact our office. Reference to o u r J o b N o . P-400123 will help-expedite a response to your inquiry. Respectfully submitted, COAST GEOTECHNICAL Mark Burwell, C.E.G. Vithaya Singhanet, P.E. Engineering Geologist Geotechnical Engineer COAST• GEOTECHNICAL CONSULTING ENGINEERS AND GEOLOGISTS February 4, 2004 Mark Petersen 185 Phoebe Street Encinitas , CA 92024 RE: PRELIMINARY GEOTECHNICAL INVESTIGATION Proposed Eleven (11) Unit Condominium 236 Date Avenue Carlsbad, California Dear Mr. Petersen: In response to your request and in accordance with our P r o p o s a l a n d A g r e e m e n t d a t e d N o v e m b e r 1.1, 2003, we have performed a preliminary geotechnical in v e s t i g a t i o n o n t h e s u b j e c t s i t e f o r t h e proposed eleven unit condominium project. The findings of t h e i n v e s t i g a t i o n , l a b o r a t o r y t e s t r e s u l t s and recommendations for foundation design are presented i n t h i s r e p o r t . From a geologic and soils engineering point of view, it is our o p i n i o n t h a t t h e s i t e i s s u i t a b l e f o r t h e proposed development, provided the recommendations in t h i s r e p o r t a r e i m p l e m e n t e d d u r i n g t h e design and construction phases. If you have any questions, please do not hesitate to conta c t u s a t (858) 755-8622. This opportunity to be of service is appreciated. Respectfully submitted, COAST GEOTECHNICAL Mark Burwell, C.E.G. Vithaya Singhanet, P.E. Engineering Geologist Geotechnical Engineer 779 ACADEMY DRIVE • SOLANA BEACH, CALIFORNIA 92075 (858) 755-8622 • FAX (858) 755-9126 PRELIMINARY GEOTECHNICAL INVESTIGAT I O N Proposed Eleven (11) Unit Condominium 236 Date Avenue Carlsbad, California Prepared For: Mark Petersen 185 Phoebe Street Encinitas , CA 92024 February 4, 2004 W.O. P-400123 Prepared By: COAST GEOTECHNICAL 779 Academy Drive Solana Beach, California 92075 TABLE OF CONTENTS VICINITY MAP INTRODUCTION 5 SITE CONDITIONS 5 PROPOSED DEVELOPMENT SITE INVESTIGATION 6 LABORATORY TESTING 6 GEOLOGIC CONDITIONS 7 CONCLUSIONS 10 RECOMMENDATIONS 11 A. BUILDING PAD-REMOVALS/RECOMPACTION 11 B. TEMPORARY SLOPES/EXCAVATION CHA R A C T E R I S T I C S 12 C. FOUNDATIONS 12 D. SLABS ON GRADE (INTERIOR AND EXTERI O R ) 13 E. RETAINING WALLS 14 F. SETTLEMENT CHARACTERISTICS 14 G. SEISMIC CONSIDERATIONS - 14 H. SEISMIC DESIGN PARAMETERS 15 I. PRELIMINARY PAVEMENT DESIGN. 15 J. UTILITY TRENCH * 16 K. DRAINAGE - 16 L. GEOTECJ{NICAL OBSERVATIONS * 17 M. PLAN REVIEW 17 LIMITATIONS 17 REFERENCES 20 APPENDICES APPENDIX A LABORATORY TEST RESULTS EXPLORATORY BORING LOGS TOPOGRAPHIC MAP APPENDIX B REGIONAL FAULT MAP SEISMIC DESIGN PARAMETERS DESIGN RESPONSE SPECTRUM APPENDIX C - GRADING GUIDELINES 0-cE :flIflfl nn.,'o : i I I... - Coast Geotechnical February 4, 2004 W.O. P-400123 Page 5 INTRODUCTION This report presents the results of our geotechni c a l i n v e s t i g a t i o n o n t h e s u b j e c t p r o p e r t y . T h e purpose of this study is to evaluate the nature and ch a r a c t à r i s t i c s o f t h e e a r t h m a t e r i a l s u n d e r l y i n g the property, the engineering properties of the surfici a l d e p o s i t s a n d t h e i r i n f l u e n c e o n t h e p r o p o s e d condominium project. SITE CONDITIONS The subject property is located east of Garfield Street, a l o n g t h e n o r t h s i d e o f D a t e A v e n u e , i n t h e city of Carlsbad. The subject' property includes nearly one (1) acre o f r e l a t i v e l y f l a t t e r r a i n . T w o ( 2 ) s i n g l e f a m i l y residences and accessory structures are located in t h e s o u t h e a s t e r n p o r t i o n o f t h e s i t e . M a x i m u m relief on the property is approximately 3.0 vertical fe e t . Drainage is generally by sheet flow to the southwest . V e g e t a t i o n i n t h e s o u t h e a s t e r n p o r t i o n o f t h e site includes grass; a vegetable garden and several tree s . T h e w e s t e r n a n d n o r t h e r n p o r t i o n s o f t h e site are generally void of vegetation. PROPOSED DEVELOPMENT Plans for the development of the property were unava i l a b l e a t t h e t i m e o f t h i s s t u d y . H o w e v e r , i t i s our understanding that an eleven (1 I unit condominium project with subterranean parki n g i s Coast GeOtechnical February 4, 2004 W.O. P-400123 Page 6 planned. It is anticipated that excavations, up to ten (10) feet, will be required for the parking structure. - SITE INVESTIGATION Site exploration included four (4) exploratory borings drilled to a maximum depth of 18 feet. Earth materials encountered were visually classified and logged by our field engineering geologist. Undisturbed, representative samples of earth materials were obtained at selected intervals. Samples were obtained by driving a thin walled steel sampler into the desired strata. The samples are retaine d in brass rings of 2.5 inches outside diameter and 1.0 inches in height. The central portion of the sample is retained in close fitting, waterproof containers and transported to our laboratory for te s t i n g and analysis. LABORATORY TESTING Classification The field classification was verified through laboratory examination, in accordance with the Unified Soil Classification System. The final classification is shown on the enclosed Exploratory Logs. Moisture/Density The field moisture content and dry unit weight were determined for each of the undisturbed s o i l samples. This information is useful in providing a gross picture of the soil consistency or variat i o n Coast Geotechnicat February 4, 2004 W.O. P-400123 Page 7 among exploratory excavations. The dry unit weight was determined i n p o u n d s per cubic foot. The field moisture content was determined as a percentage of the dry u n i t w e i g h t . B o t h a r e s h o w n o n the enclosed Laboratory Tests Results and Exploratory Logs. Maximum Dry Density and Optimum Moisture Content The maximum dry density and optimum moisture content were determi n e d f o r s e l e c t e d s a m p l e s o f earth materials taken from the site. The laboratory standard tests were i n a c c o r d a n c e w i t h A S T M D-1557-91. The results of the tests are presented in the Laboratory Te s t R e s u l t s . GEOLOGIC CONDITIONS The subject property is located in the Coastal Plains Physiographi c P r o v i n c e o f S a n D i e g o . T h e property is underlain at relatively shallow depths by Pleistocene ter r a c e d e p o s i t s . T h e t e r r a c e deposits are underlain at depth by Eocene-age sedimentary rock s w h i c h h a v e c o m m o n l y b e e n designated as the Santiago Formation on published geologic maps. The t e r r a c e d e p o s i t s a r e c o v e r e d by soil deposits and, in part, by fill deposits. A brief description of the e a r t h m a t e r i a l s e n c o u n t e r e d on the site follows. Artificial Fill No evidence of significant fill deposits were observed on the site. Minor f i l l d e p o s i t s , u p t o 1 . 0 f o o t , appear to be located along the north and western portion of the prope r t y . A d d i t i o n a l m i n o r f i l l deposits are present in and around the existing structures. The fill is c o m p o s e d o f t a n t o b r o w n s i l t y fine and medium-grained sand in a moist and loose condition. Coast Geotechnical February 4, 2004 W.O. P-400123 Page 8 Residual Soil Site exploration suggests the underlying terrace deposits are blanketed by approximately 12 t o 1 8 inches of brown fine and medium-grained sand. The soil is generally moist and loose. Th e c o n t a c t with the underlying terrace deposits is gradational and may vary across the site. Terrace Deposits Underlying the surficial materials, poorly consolidated Pleistocene terrace deposits are p r e s e n t . T h e terrace deposits are composed of reddish brown slightly clayey, fine and medium- g r a i n e d s a n d . The sediments grade to weakly cemented, tan, fine and medium-grained sand. Regi o n a l l y , t h e Pleistocene sands are considered flat-lying and are underlain at depth by Eocene-age sedi m e n t a r y rock units Expansive Soil Based on our experience in the area and previous laboratory testing of selected sampl e s , t h e f i l l deposits, residual soil and Pleistocene sands reflect an expansion potential in the low r a n g e . Groundwater No evidence of perched or high groundwater tables were encountered to the depth exp l o r e d . However, it should be noted that seepage problems can develop after completion of constr u c t i o n . These seepage problems most often result from drainage alterations, landscaping and over - i r r i g a t i o n . In the event that seepage or saturated ground does occur, it has been our experience that t h e y a r e most effectively handled on an individual basis. Coast Geotechnical February 4, 2004 W.O. P-400123 , Page 9 Tectonic Setting The site is located within the seismically active southern California region w h i c h i s g e n e r a l l y characterized by northwest trending Quaternary-age fault zones. Several of thes e f a u l t z o n e s a n d fault segments are classified as active by the California Division of Mines and Geol o g y ( A i q u i s t - Priolo Earthquake Fault Zoning Act). Based on a review Of published geologic maps, no known faults transverse the site. Th e n e a r e s t active fault is the offshore Rose Canyon Fault Zone located approximately 4.4 'miles west o f t h e s i t e It should be noted that the Rose Canyon Fault is not a continuous, well-defined feature b u t r a t h e r a zone of right stepping en echelon faults. The complex series of faults has been ref e r r e d t o a s t h e Offshore Zone of Deformation (Woodward-Clyde, 1979) and is not fully understood. S e v e r a l s t u d i e s suggest that the Newport-Inglewood and the Rose Canyon faults are a continuous zo n e o f e n e c h e l o n faults (Treiman, 1984). Further studies along the complex offshore zone of faulting m a y i n d i c a t e a potentially greater seismic risk than current data suggests. Other faults which could affe c t t h e s i t e include the Coronado Bank, Elsinore, San Jacinto and San Andreas Faults. The p r o x i m i t y o f m a j o r faults to the site and site parameters are shown on the enclosed Seismic Design Pa r a m e t e r s . Liquefaction Potential Liquefaction is a process by which a sand mass loses its shearing strength completely an d f l o w s . T h e temporary transformation of the material into a fluid mass is often associated wi t h g r o u n d m o t i o n resulting from an earthquake. Coast Geotechnical February 4, 2004 W.O. P-400123 Page 10 Owing to the moderately dense nature of the Pleistocene terrace deposits and the anticipated depth to groundwater, the potential for seismically induced liquefaction and soil instability is considered low. CONCLUSIONS The subject property is located in an area that is relatively free of potential geologic hazards such as landsliding, liquefaction, high groundwater conditions and seismically induced subsidence. The existing fill, soil and weathered terrace deposits are not suitable for the support of proposed footings and concrete flatwork. These surficial deposits should be removed and replaced as properly compacted fill deposits in areas outside the proposed subterranean walls. Disturbed soils resulting from the demolition of structures and utility lines should be removed and replaced as compacted fill, where applicable. It is anticipated that the subterranean parking excavation will extend through the surficial deposits encountered on the site and into Pleistocene terrace deposits. However, if loose materials are encountered in the area of the proposed basement slab they should be compacted. All retaining wall footings should penetrate loose or weathered materials and founded the design depth into competent terrace deposits. Coast Geotechnical February 4, 2004 W.O. P-400123 Page 11 RECOMMENDATIONS Building Pad-Removals/Recompaction If structural footings are planned outside the proposed subterranean walls, the existing fill, soil and weathered terrace deposits should be removed and replaced as properly compacted fill. All fill should be keyed and benched into the underlying terrace deposits. Removals should include the entire building pad, extending a minimum of 5.0 feet beyond the building footprint, where applicable. The depth of removals are anticipated to be on the order of 3.0 feet. However, deeper removals may be necessary due to demolition of structures and removal of existing utility lines.. Most of the existing earth deposits are generally suitable for reuse, provided they are cleared of all vegetation, debris and thoroughly mixed. Prior to placement of fill, the base of the removal should be observed by a representative of this firm. Additional overexcavation and recommendations may be necessary at that time. The exposed bottom should be scarified to a minimum depth of 6.0 inches, moistened as required and compacted to a minimum of 90 percent of the laboratory maximum dry density. Fill should be placed in 6.0 to 8.0 inch lifts, moistened to approximately 1.0 - 2.0 percent above optimum moisture content and compacted to a minimum of 90 percent of the laboratory maximum dry density.. Fill, soil and weathered terrace deposits in areas of proposed concrete flatwork and driveways should be removed and replaced as properly compacted fill. Imported fill, if necessary, should consist of non-expansive granular deposits approved by the geotechriical engineer. . Coast Geotechnical February 4, 2004 W.O. P-400123 Page 12 Temporary Slopes/Excavation Characteristics Temporary excavations should be trimmed to a gradient of 3/4:1 (horizontal to vertical) or less depending upon conditions encountered during grading. The Pleistocene terrace deposits are generally weakly cemented but may contain hard concretion layers. Based on our experience in the area, the sandstone is easily rippable with conventional earth moving equipment in good working order. Foundations The following design parameters are based on footings founded into non-expansive approved compacted fill deposits or competent terrace deposits. Footings for the proposed residences should be a minimum of 12 inches wide and founded a minimum of 12 inches and 18 inches below the lower most adjacent subgrade at the time of foundation construction for single-story and two-story structures, respectively. A 12 inch by 12 inch grade beam should be placed across the garage opening. Footings should be reinforced with a minimum of four No. 4 bars, two along the top of the footing and two along the base. Footing recommendations provided herein are based upon underlying soil conditions and are not intended to be in lieu of the project structural engineers design. For design purposes, an allowable bearing value of 1500 pounds per square foot may be used for foundations at the recommended footing depths. The bearing value may be increased to 2000 pounds per square foot for subterranean retaining wall footings. Coast Geotechnical February 4, 2004 W.O. P-400123 Page 13 The bearing value indicated above is for the total dead and frequently applied live loads. This value may be increased by 33 percent for short durations of loading, including the effects of wind and seismic forces. Resistance to lateral load may be provided by friction acting at the base of foundations and by passive earth pressure. A coefficient of friction of 0.35 may be used with dead-load forces. A passive earth pressure of 300 pounds per square foot, per foot of depth of fill or terrace deposits penetrated to a maximum of 2000 pounds per square foot may be used. Slabs on Grade (Interior and Exterior) Slabs on grade should be a minimum of 4.0 inches thick and reinforced in both directions with No. 3 bars placed 16 inches on center in both directions. The slab should be underlain by a minimum 2.0-inch sand blanket. Where moisture sensitive floors are used, a minimum 6.0-mil Visqueen or equivalent moisture barrier should be placed over the sand blanket and covered by an additional two inches of sand. Utility trenches underlying the slab may be backfilled with on-site materials, compacted to a minimum of 90 percent of the laboratory maximum dry density. Slabs including exterior concrete flatwork should be reinforced as indicated above and provided with saw cuts/expansion joints, as recommended by the project structural engineer. All slabs should be cast over dense compacted subgrades. Coast Geotechnical February 4, 2004 W.O. P-400123 Page 14 Retaining Walls Cantilever walls (yielding) retaining nonexpansive granular soils may be designed for an active- equivalent fluid pressure of 35 pounds per cubic foot. Restrained walls (nonyielding) should be designed for an "at -rest" equivalent fluid pressure of 58 pounds per cubic foot. Wall footings should be designed in accordance with the foundation design recommendations. All retaining walls should be provided with an adequate backdrainage system (Miradrain 6000 or equivalent is suggested). The soil parameters assume a level granular backfill compacted to a minimum of 90 percent of the laboratory maximum dry density Settlement Characteristics Estimated total and differential settlement over a horizontal distance of 30 feet is expected to be on the order of 3/4 inch and V2 inch, respectively. It should also be noted that long term secondary settlement due to irrigation and loads imposed by structures is anticipated to be 1/4 inch. Seismic Considerations Although the likelihood of ground rupture on the site is remote, the property will be exposed to moderate to high levels of ground motion resulting from the release of energy should an earthquake occur along the numerous known and unknown faults in the region. The Rose Canyon Fault Zone located approximately 4.4 miles west of the property is the nearest known active fault and is considered the design earthquake for the site. A maximum probable event Coast Geotechnical February 4, 2004 W.O. P-400123 Page 15 along the offshore segment of the Rose Canyon Fault is expected to produce a peak bedrock horizontal acceleration of 0.36g and a repeatable ground acceleration of 0.23g. - Seismic Design Parameters (1997 Uniform Building Code) Soil Profile Type - SD Seismic Zone - 4 Seismic Source - Type B Near Source Factor (Ny) - 1.1 Near source Acceleration Factor (Na) - 1.0 Seismic Coefficients Ca = 0.44 C= 0.72 Design Response Spectrum T=0.652 T0 =0.130 Nearest Type B Fault - 4.4 miles Preliminary Pavement Design The following pavement section is recommended for proposed driveways: 4.0 inches of asphaltic paving or 4.0 inches of concrete on 6.0 inches of select base (Class 2) on 12 inches of compacted subgrade soils Subgrade soils should be compacted to the thickness indicated in the structural section and.left in a condition to receive base materials. Class 2 base materials should have a minimum R-value of 78 Coast Geotechnical February 4, 2004 W.D. P-400123 Page 16 and a minimum sand equivalent of 30. Subgrade soils and base materials should be c o m p a c t e d t o a minimum of 95 percent of their laboratory maximum dry density. The pavement section should be protected from water sources. Migration of water into s u b g r a d e deposits and base materials could result in pavement failure. Utility Trench We recommend that all utilities be bedded in clean sand to at least one foot above the t o p o f t h e conduit. The bedding should be flooded in place to fill all the voids around the conduit. Im p o r t e d or on-site granular material compacted to at least 90 percent relative compaction maybe ut i l i z e d f o r backfill above the bedding. The invert of subsurface utility excavations paralleling footings should be located a b o v e t h e z o n e of influence of these adjacent footings. This zone of influence is defined as the area below a 45 degree plane projected down from the nearest bottom edge of an adjacent footing. This c a n b e accomplished by either deepening the footing, raising the invert elevation of the utili t y , o r m o v i n g the utility or the footing away from one another. Drainage Specific drainage patterns should be designed by the project architect or engineer. How e v e r , i n general, pad water should be directed away from foundations and around the structure t o t h e s t r e e t . Coast Geotechnical February 4, 2004 W.O. P-400123 Page 17 Roof water should be collected and conducted to the street, via non-erodible devices. Pad water should not be allowed to pond. Vegetation adjacent to foundations should be avoided. If vegetation in these areas is desired, sealed planter boxes or drought resistant plants should be considered. Other alternatives may be available, however, the intent is to reduce moisture from migrating into foundation subsoils. Irrigation should be limited to that amount necessary to sustain plant life. All drainage systems should be inspected and cleaned annually, prior to winter rains. Geotechnical Observations Structural footing excavatibns should be observed by a representative of this firm, prior to the placement of steel and forms. All fill should be placed while a representative of the geotechnical engineer is present to observe and test. Plan Review A copy of the final plans should be submitted to this office for review prior to the initiation of construction. Additional recommendations may be necessary at that time. FA LIMITATIONS This report is presented with the provision that it is the responsibility of the owner or the owner's representative to bring the information and recommendations given herein to the attention of the project's architects and/or engineers so that they may be incorporated into plans. Coast Geotechnical February 4, 2004 W.O. P-400123 Page 18 If conditions encountered during construction appear to differ from those described in this report, our office should be notified so that we may consider whether modifications are needed. No responsibility for construction compliance with design concepts, specifications or recommendations given in this report is assumed unless on-site review is performed during the course of construction. The subsurface conditions, excavation characteristics and geologic structure described herein are based on individual exploratory excavations made on the subject property. The subsurfac e conditions, excavation characteristics and geologic structure discussed should in 'way be construed to reflect any variations which may occur among the exploratory excavations. Please note that fluctuations in the level of groundwater may occur due to variations in rainfall, temperature and other factors not evident at the time measurements were made and reported herein. Coast Geotechnical assumes no responsibility for variations which may occur across the site. The conclusions and recommendations of this report apply as of the current date. In time, however, changes can occur on a property whether caused by acts of man or nature on this or adjoining properties. Additionally, changes in professional standards may be brought about by legislation o r the expansion of knowledge Consequently, the conclusions and 'recommendations of this report . may be rendered wholly or partially invalid by events beyond our áontrol. This report is ther e f o r e subject to review and should not be relied upon after the passage of two years. The professional judgments presented herein are founded partly on our assessment of the tec h n i c a l Coast Geotechnical February 4, 2004 W.O. P-400123 Page 19 data gathered, partly on our understanding of the proposed construction a n d p a r t l y o n o u r g e n e r a l experience in the geotechnical field. However, in no respect do we g u a r a n t e e t h e o u t c o m e o f t h e project. This study has been provided solely for the benefit of the client and is i n n o w a y i n t e n d e d t o b e n e f i t or extend any right or interest to any third party. This study is not to b e u s e d o n o t h e r p r o j e c t s o r extensions to this project except by agreement in 1kriting with Coast G e o t e c h n i c a l . Coast Geotechnical February 4, 2004 W.O. P-400123 Page 20 REFERENCES Hays, Walter W., 1980, Procedures for Estimating Earthquake Ground Motions, Geological Survey Professional Paper 1114, 77 pages. Kennedy, M.P., and Peterson, G.L., 1975, Geology of the San Diego Metropolitan Area, California: California Division of Mines and Geology, Bulletin 200, Plate IA . Seed, H.B., and Idriss, TM., 1970, A Simplified Procedure for Evaluating Soil Liquefacti o n Potential: Earthquake Engineering Research Center. Tan, S.S., and Giffen, D.G., 1995, Landslide Hazards in the Northern Part of the San Diego Metropolitan Area, San Diego County, Plate 35A, Open-File Report 95-04, Map Scale 1:24,000. Treiman, J.A., 1984, The Rose Canyon Fault Zone, A Review and Analysis, California Division of Mines and Geology. MAPS/AERIAL PHOTOGRAPHS Aerial Photograph, 1982, Foto-Map D-7, Scale 1 "=2000'. California Division of Mines and Geology, 1994, Fault Activity Map of California, Scale 1=750,000'. . Conway and Associates, 2003 , Topographic Map, 236 Date Avenue, Scale l"20'. Geologic Map of the Oceanside, San Luis Rey and San Marcos 7.5' Quadrangles, 1996, DMG Open File Report 96-02. . U.S.G.S., 7.5 Minute Quadrangle Topographic Map, Digitized, Scale Variable. r APPENDIX A LABORATORY TEST RESULTS TABLE I Maximum Dry Density and Optimum Moisture Content (Laboratory Standard ASTM D-1557-91) Sample Max. Dry Optimum Location Density Moisture Content (pcf) B-i @ 0.5 1 -3.0' 128.4 10.2 TABLE II Field Dry Density and Moisture Content Sample Field Dry Field Moisture Location Density Content (pcf) 06 B-i @ 2.0' 91.4 10.2; B-i @ 4.0' 100.0 8.7 B-i @ 6.0' 97.2 9.0 B-i ® 8.0' 104.4 7.5 B-i @ 10.0' 95.3 5.6 B-i @ 12.0' 107.5 4.7 B-i @ 15.0' 108.1 4.2 B-2 @ 1.5' 100.7 5.1 B-2 @ 3.0' 123.7 8.0 B-2 @ 5.0' 118.1 7.3 B-2 © 8.0' 116.3 8.5 B-2 @ 10.0' 104.7 7.9 B-2 © 12.0' 105.1 6.9 B-3 © 3.0' 120.9 6.0 B-3 © 6.0' 106.1 6.7 B-3 @ 9.0' 108.2 5.1 B-3 © 12.0' 107.8 4.6 B-4 @ 2.0' 97.6 5.3 B-4 @ 4.0' 117.2 7.9 B-4 © 6.0' 98.1 6.9 B-4 @ 8.0' 106.1 5.4 B-4 © 10.0' 106.3 5.6 B-4 © 12.0' 104.0 7.4 P-400123 : LOG OF EXPLO R A T O R Y B O R I N G N O . 1 DRILL RIG: PORTABLE BUCKET AUGER PROJECT NO. P-400123 BORING DIAMETER: 3.5" DATE DRILLED: 12-'111-03 SURFACE ELEV.: 47' (Approximate) LOGGED BY: MB ZO I I GEOLOGIC DESCRIPTION 47.00 - 0.00 SM FILL (of): Brown silty, fine and medium-grained sand, moist, loose SM SOIL (Qs): Brown fine and med.-grained slightly silty sand, moist, loose • - 45. SM TERRACE DEPOSITS (Qt): Reddish brn, fine and med.-grained sand, moist, we 91.4 10.2 I W in upper 2.0' - 2.00 - 43.0 100.0 8.7 4.00 - 41.0 97.2 9.0 - 6.00 0) - - 39.0 - 8.00 104.4 7.5 - From 9 Grades to weakly cemented tan fine and med.-grained sand 0 - 37.0. 95.3 5.6 6 - 10.0 z - - 35.0 107.5 4.7 - 12.0 - 33.0 - 14.0 108.1 4.2 - 31.0 - 16.0 . End of Boring @18' - 29.0 ________ _______________________________________________________________________ _ _ _ _ _ _ _ SHtffT I (.)F I 18.00 COAST GEOTECHNICAL • LOG OF EXPLORATORY BORING N O . 2 DRILL RIG: PORTABLE BUCKET AUGER PROJECT NO. P.400123 BORING DIAMETER: 3.5" DATE DRILLED: 12-11-03 SURFACE ELEV.: 47; (Approximate) LOGGED BY: MB Cl) GEOLOGIC DESCRIPTION 47.00f j - 0.00 SM FILL (as): Brown silty, fine and med.-grained sand, moist , loose SM SOIL (Qs): Brown fine and med.-grained slightly silty sand, moist, too 100.7 5.1 -45.0 - 2.00! SM TERRACE DEPOSITS (Qt): Reddish brn., fine and med.-grained sar 123.7 8.0 - -(3W 43.0 Slightly clayey - 4.00 118.1 7.3 . I 41.0 6.00 CD - 0 - I- a) - - 39.0 116.3 8.5 -. 800 • . o 0 - 37.0 10.0 104.7 7.9 Z - 35.0 105.1 6.9 - 12.0 • . • - 33.0 • 14.0 - • 31.0 - • 16.0 SIII3RT I OF I From 16.5' Grades to weakly cemented tan fine and med:-grained sand End of Boring @ 17' COAST GEOTECHNICAL LOG OF EXPLORATORY BORING NO. 3 , DRILL RIG: PORTABLE BUCKET AUGER PROJECT NO. P-400123 BORING DIAMETER: 3.5" DATE DRILLED: 12-11-03 SURFACE ELEV.: 47' (Approximate) LOGGED BY: MB En. H 0 U uI.z J co c,) (I) GEOLOGIC DESCRIPTION 47.00 = 0.00 SM SOIL (Qs): Brown fine and med.-grained slightly silty sand, moist, loose 46.0 LOO SM TERRACE DEPOSITS (Qt): Reddish bm., fine and med.-gained sand, moist = 45.0 = 2.00 , Slightly clayey 44.0 120.9 6.0 300 43.0 = 4.00 - 42.0 = 5.00 1) = - o = 41.0 6.00 106.1 6.7 cu = 40.0 7.00 (5 = 39.0 o = 8.00 108.2 5.1 38.0 Grades to weakly cemented tan fine and med.-grained sand 9.00 = 37.0 = 10.0 = 36.0 • -= 11.0 = 35.0 107.8 4.6 12.0 34.0 • = 13.0 End of Boring @ 14' - , 5HflIT I OF I , COAST GEOTECHNICAL LOG OF EXPLOR A T O R Y B O R I N G N O . 4 DRILL RIG: PORTABLE BUCKET AUGER PROJECT NO. P-400123 BORING DIAMETER: 3.5" . DATE DRILLED: 12-18-03 SURFACE ELEV.: 47' (Approximate) LOGGED BY: MB. I I . S ,• 0 0 . . GEOLOGIC DESCRIPTION 47.00 = 0.00 SM SOIL (Qs): Brown fine and med.-grained slightly silty sand, dry, loose = 46.0 1.00 Graditional Contact = 45.0 SM TERRACE DEPOSITS (Qt): Reddish brn., fine and med.-grained sand, moist 97.6 5.3 2.00 E sio Slightly moist to 3', slighty clayey and moist below = 3.00 43.0 1172 79 400 42.0 5.00 0 41.0 98.1 .6.9 1..= . 6.00 40.0 - From 7' Grades to weakly cemented greyish tan fine and med.-grained 7.00 sand. 0 I-, = - 39.0 = 8.00 106.1 5.4 0 z = 38.0 = 9.00 37.0 106.3 5.6 10.0 36.0 = 11.0 5 35.0 104.0 7.4 • 12.0 . = 34.0 . = 13.0 = . End of Boring @ 14' SHIET I OF I c' -r rrr'LjKllr'A I I '..L..%.J I L.'sjl IIl'tL LOTS \ \ .1 c S - - - (Qt / (COVERED BY Of & QS) 1 / Tr \ TOPOGRAPHIC MAP ' (c•_ SCALE: REDUCED T \ 2 GEOLOGIC UNITS Qs RESIDUAL SOIL NN 43 - - -=--=- Qt TERRACE DEPOSITS COAST GEOTECHNICAL P400123 Qt S (COVERED BY Qs) •: l u DA AVE Xv- I • .5 I I 0 I •I I. - I H APPENDIX B ui. i 3i ¼tI\\\\J \ 5 . .,. •.!\•• • q — ,, 1 L &4ç, XT REGIONAL FAULT MAP EXPLANATION la.h •Sa.s a. LJ is, SMCMCd b, aid I. .t.. abs baad. bp da —' -- ia.d0l7 l.aWa F,a.d abab7 7 a a, hip. Faa Sit a, - itflS Ci, cia. fail.. thi Cna Silky - a,a..ud , ida. n.nf nO.57 41.hat Liii. S a. FAULT CLASSIFICATION COLOR CODE (Ifldscaong Raay 0( MOvbmaOf) F- —1 --t- ha. IT yC&flfthi$cii itatLlkaldlaa,g — api.. AACS - — ad idait C,S by g'aiiba i1id5 Si..tg u.0.Ma. . a. paid bSM.. fli. 'ba1 b..aabyp.. a-...Td.aba,. ud hish 19521 Thu &ai. Ii 6, ..d.caS. ataaifly I .0 mm a. - - a, Sb, lalS Sa., 515ppg!. W'- gSd s.pi.u.a.. _,.a,il, St&afl.. iS_a.. Udap&.cS S.,?sa, l.a. PitS bad rr,-....... .dasdai tS!Sos...a baa,.,, S aan bad SPECIAL NOTATIONS iA1( (r'('17 A i r do. ) '. •" •.\—-- . ç 1 a 12 24mi1es GIC SCALE -: ' MEXICO COAST GEOTECHUCAL * * * UBCS•EI S " * * Version 1.03 * * * *** ** * * * * ** ** *** ** ** COMPUTATION OF 1997 UNIFORM BUILDING CODE SEISMIC DESIGN PARAMETERS JOB NUMBER: P-400123 DATE: 01-13-2004 JOB NAME: PETERSON FAULT-DATA-FILE NAME: CDMGUBCR.DAT SITE COORDINATES: SITE LATITUDE: 33.1465 SITE LONGITUDE: 117.3410 UBC SEISMIC ZONE: 0.4 UBC SOIL PROFILE TYPE: SD NEAREST TYPE A FAULT: NAME: ELSINORE-JULIAN DISTANCE: 39.9 km NEAREST TYPE B FAULT: NAME: ROSE CANYON DISTANCE: .7.0 km NEAREST TYPE CFAULT: NAME: . DISTANCE: 99999.0 km SELECTED UBC SEISMIC COEFFICIENTS: Na: 1.0 Nv: 1.1 Ca: 0.44 Cv: 0.72 Ts: 0.652 To: 0.130 --------------------------- SUMMARY OF FAULT PARAMETERS --------------------------- Page 1 --------------------------------------------------- - - - - - - - - - - - - - - - - - - - - - - - - - - - - I APPROX. ISOURCE I MAX. I SLIP I FAULT ABBREVIATED IDISTANCEJ TYPE I MAG. I RATE I TYPE FAULT NAME I (km) I (A,B,C) I (MW) I (inm/yr) I (SS,DS,BT) I I•====== I ========= ROSE CANYON NEWPORT-INGLEWOOD (Offshore) CORONADO BANK ELS INORE-TEMECULPL ELSINORE-JULIAN ELSINORE-GLEN IVY PALOS VERDES EARTHQUAKE VALLEY NEWPORT-INGLEWOOD (L.A.Basin) SAN JACINTO-ANZA SAN JACINTO-SAN JACINTO VALLEY CHINO-CENTRAL AVE. (Elsinore) ELSINORE-WHITTIER SAN JACINTO-COYOTE CREEK ELSINORE-COYOTE MOUNTAIN SAN JACINTO-SAN BERNARDINO SAN ANDREAS - Southern SAN JACINTO - BORREGO SAN JOSE CUCAMONGA SIERRA MADRE (Central) PINTO MOUNTAIN NORTH FRONTAL FAULT ZONE (West C LEGHORN BURNT MTN. RAYMOND C LAMS HELL- SAWP IT SAN J\NDREAS - 1857 Rupture EUREKA PEAK NORTH FRONTAL FAULT ZONE (East VERDUGO SUPERSTITION MTN. (San Jacintc HOLLYWOOD ELMORE RANCH SUPERSTITION HILLS (San Jacint LANDERS HELENDALE - 5 LOCKHARDT ELSINORE-LAGUNA SALADA SANTA MONICA MALIBU COAST LENWOOD-LOCKHART-OLD WOMAN SPI BRAWLEY SEISMIC ZONE SIERRA MADRE (San Fernando) JOHNSON VALLEY (NortherD) EMERSON So. - COPPER MTN. ANACAPA- DUNE I 7.0 1 B I 6.9 1 1.50 I SS I 8.3 I B I 6.9 I 1.50 I SS I 33.1 .1 B 1 7.4 I 3.00 I SS 39.6 1 B I 6.8 I 5.00 I SS I 39.9 I A 7.1 1 5.00 I SS 55.2 1 B 1 6.8 I 5.00 I SS 57.6 I B I 7.1 1 3.00 I SS I 70.8 I B I 6.5 1 2.00 1 SS I 74.4 I B I 6.9 I 1.00 I SS I 76.0 I A I 7.2 I 12.00 I. SS 76.9 I B 1 6.9 I 12.00 I SS I 77.1 I B 1 6.7 I 1.00 I DS I 83.4 I B I 6.8 I 2.50 1 SS I 84.9 I B I 6.8 I 4.00 1 SS I 93.4 I B I 6.8 I 4.00 1 SS 97.1 1 B I 6.7 I 12.00 I. SS I 105.4 1 A I 7.4 I 24.00 I SS I 107.0 1 B I 6.6 I 4.00 I SS I 110.4 1 B I 6.5 I 0.50 I DS I 114.7 1 A I 7.0 I 5.00 I DS I 114.8 B I 7.0 I 3.00 I DS I 116.6 B I 7.0 I 2.50 I SS I 123.6 1 B 1 7.0 I 1.00 I DS 125.7 I B I 6.5 1 3.00 1 SS 126.3 I B I 6.5 I 0.60 I SS I 129.2 I B I 6.5 1 0.50 I DS 129.8 I B I 6.5 I 0.50 1 DS 130.6 I A I 7.8 I 34.00 I 55 130.8 I B 1 6.5 I 0.60 1 SS 132.1 I B 1 6.7 I 0.50 I DS I 133.1 B I 6.7 I 0.50 I DS I 133.2 I B I 6.6 1 5.00 I SS I 136.2 I B 6.5 I 1.00 I DS I 139.0 B I 6.6 I 1.00 1 SS I 140:7 I B 'I 6.6 I 4.00 I Ss I 142.1. I B I 7.3 1 0.60 1 SS I 143.0 I B 1 7.1 I 0.60 SS I 143.7 I B I 7.0 1 3.50 I SS I 143.8 I B I 6.6 I 1.00 I DS I 148.2 1 B 1 6.7 1 0.30 1 DS ;s I 149.5 I B I 7.3 1 0.60 I SS 153.8 I B 1 6.5 1 25.00 I SS 154.0 1 B 1 6.7 I 2.00 1 DS 154.6 I B I 6.7 I 0.60 I SS I 155.3 1 B I 6.9 I 0.60 I SS 1 156.8 1 B 1 7.3 1 3.00 1 DS --------------------------- SUMMARY OF FAULT PARAMETERS Page 3 I APPROX. ISOURCE I MAX. I SLIP I FAULT ABBREVIATED IDPSTANCEI TYPE I MAG. I RATE I TYPE FAULT NAME I (km) I (A,B,C) I (Mw) I (xnm/yr) (SS,DS,BT) DEATH VALLEY (N. of Cucamongo) I 464.3 I A I I I 7.0 I ========= 5.00 I 1 SS ROUND VALLEY (E. of S.N.Mtns.) 1 470.8 I B I 6.8 1 1.00 I DS FISH SLOUGH I 478.7 I B I 6.6 I 0.20 I DS HILTON CREEK I 496.9 1 B I 6.7 1 2.50 1 DS ORTIGALITA I 521.0 I B I 6.9 I 1.00 I SS HARTLEY SPRINGS I 521.2 I B I 6.6 I 0.50 I DS CALAVERAS (So.of Calavéras Res) I 526.6 B I 6.2 I 15.00 I SS MONTEREY BAY - TULARCITOS I 529.2 I B I 7.1 I 0.50 I DS PALO COLORADO - SUR. I 530.3 I B I 7.0 3.00 I SS QUIEN SABE I 539.8 I B 1 6.5 1 1.00 I SS MONO LAKE I 557.1 I B 1 6.6 I. 2.50 I DS ZAYANTE-VERGELES I 558.3 I B I 6.8 0.10 I SS SAN ANDREAS (1906) 563.5 I A I 7.9 I 24.00 I SS SARGENT I 563.6 I B 1 6.8 3.00 I S'S ROBINSON CREEK I 588.4 1 B I 6.5 I 0.50 1 DS SAN GREGORIO I 604.6 I A I 7.3 I 5.00 I SS GREENVILLE 613.41 B I 6.9 I 2.00 I SS MONTE VISTA - SHANNON 1 613.7 I B I 6.5 I 0.40 I DS HAYWARD (SE Extension) I 613.8 I B I 6.5 I 3.00 I SS ANTELOPE VALLEY I 628.7 I B I 6.7.1 0.80 I DS HAYWARD (Total Length) I 633.5 I A I 7.1 1 9.00 I SS CALAVERAS (No.of Calaveras Res) I 633.5 I B I 6.8 I 6.00 I SS GENOA I 654.0 I B I 6.9 I 1.00 I DS CONCORD - GREEN VALLEY I 681.3 I B l 6.9 I 6.00 I SS RODGERS CREEK I 720.0 I ,A I 7.0 I 9.00 I 55 WEST NAPA I 720.9 .1 B I 6.5 I 1.00 I SS POINT REYES I 738.9 I B I 6.8 0.30 I DS HUNTING CREEK - BERRYESSA I 743.4 I B I 6.9 I 6.00 I SS MAACAMA (South) I 782.8 I B I 6.9 I 9.00 I SS COLLAYOMI I 799.7 I B I 6.5 I 0.60 I SS BARTLETT SPRINGS I 803.2 I A I 7.1 I 6.00. .1 SS MAACAMA (Central) I 824.4 I A 7.1 I 9.00 I SS MAACAMA (North) I 883.9 I A I 7.1 I 9.00 I SS ROUND VALLEY (N.. S.FBay) I 890.1 I B . 6.8 I 6.00 I SS BATTLE CREEK I 913.7 I B I 6.5 I 0.50 .1 OS LAKE MOUNTAIN I 948.5 I B I 6.7 I 6.00 I SS GARBERVILLE-BRICELAND I 965.6 I B 1. 6.9 I 9.00 I SS MENDOCINO FAULT ZONE 1 ,1021.9 I A I 7.4 1 35.00 I DS LITTLE SALMON (Onshore) I 1028.6 I A I 7.0 I 5.00 I DS MAD RIVER I 1031.4 I B I 7.1 I 0.70 I DS CASCADIA SUBDUCTION ZONE I 1035.6 I A I 8.3 I 35.00 I OS McKINLEYVILLE I 1041.8 I B ' I 7.0 I 0.60 I . DS TRINIDAD I 1043.3 I B I 7.3 I 2.50 I DS FICKLE HILL I 1043.8 I B I 6.9 I 0.60 I OS TABLE BLUFF I 1049.2 I B I 7.0 I 0.60 I OS LITTLE SALMON (Offshore) 1 1062.5 1 B 1 7.1 1 1.00 1 DS DESIGN-RESPONSE SPECTRUM, Seismic Zone: 0.4 Soil Profile: SD 2.5 2.O 0 1.5 ci) I. 0.0 0.5 1.0 1.5 2.0 2.5 .3.0 .3.5 4.0 4.5 5.0 Period Seconds 1 APPENDIX'C GRADING GUIDELINES Grading should be performed to at least the minimum requirements of the governing agencies, Chapter 33 of the Uniform Building Code, the geotechnical report and the guidelines presented below. All of the guidelines may not appl' to a specific site and additional recommendations may be necessary during the grading phase. Site Clearing Trees, dense vegetation, and other deleterious materials should be removed from the site. Non- organic debris or concrete may be placed in deeper fill areas under direction of the Soils engineer. Subdrainae During grading, the Geologist and Soils Engineer should evaluate the necessity of placing additional drains. All subdrainage systems should be observed by the Geologist and Soils Engineer during construction and prior to covering with compacted fill. Consideration should be given to having subdrains located by the project surveyors. Outlets should be located and protected. Treatment of Existing Ground All heavy vegetation, rubbish and other deleterious materials should be disposed of off site. All surficial deposits including alluvium and colluvium should be removed unless otherwise indicated in the text of this report. Groundwater existing in the alluvial, areas may make excavation difficult. Deeper removals than indicated in the text of the report may be necessary due to saturation during winter months. Subsequent to removals, the natural ground should be processed to a depth of six inches, moistened to near optimum moisture conditions and compacted to fill standards. Fill Placement Most site soil and bedrock may be reused for compacted fill; however, some special processing or handling may be required (see report). Highly organic or contaminated soil should not be used for compacted fill. Material used in the compacting process should be evenly spread, moisture conditioned, processed, and compacted in thin lifts not to exceed six inches in thickness to obtain a uniformly dense layer. The fill should be placed and compacted on a horizontal plane, unless otherwise found acceptable by the Soils Engineer. (1) If the moisture content or relative density varies from that acceptable to the Soils engin e e r , the Contractor should rework the fill until it is in accordance with the following: Moisture content of the fill should be at or above optimum moisture. Moisture should be evenly distributed without wet and dry pockets. Pre-watering of cut or removal areas should be considered in addition to watering during fill placement, particularly in clay or dry surficial soils. Each six inch layer should be compacted to at least 90 percent of the maximum density in compliance with the testing method specified by the controlling governmental agency. In this case, the testing method is ASTM Test Designation D-1557-91. 4. Side-hill fills should have a minimum equipment-width key at their toe excavated throu g h all surficial soil and into competent material (see report) and tilted back into the hill. As the fill is elevated, it should be benched through surficial deposits and into competent bedro c k or other material deemed suitable by the Soils Engineer. Rock fragments less than six inches in diameter may be utilized in the fill, provided: They are not placed in concentrated pockets; There is a sufficient percentage of fine-grained material to surround the rocks; The distribution of the rocks is supervised by the Soils Engineer. Rocks greater than six inches in diameter should be taken off site, or placed in accor d a n c e with the recommendations of the Soils Engineer in areas designated as suitable for rock disposal. In clay soil large chunks or blocks are common; if in excess of six (6) inches minimum dimension then they are considered as oversized. Sheepsfoot compactors or other suitabl e methods should be used to break the up blocks. The Contractor should be-required to obtain a minimum relative compaction of 90 per c e n t out to the finished slope face of fill slopes. This may be achieved by either overbuilding t h e slope and cutting back to the compacted core, or by direct compaction of the slope face W i t h suitable equipment. If fill slopes are built "at grade" using direct compaction methods.then the slope constru c t i o n should be performed so that a constant gradient is maintained throughout construction. Soil should not be "spilled" over the slope face nor should slopes be "pushed out" to obtai n grades. Compaction equipment should compact each lift along the immediate top ofslo p e . Slopes should be back rolled approximately every 4 feet vertically as the slope is b u i l t . Density tests should be taken periodically during grading on the flat surface of the fill three to five feet horizontally from the face of the slope. (2) In addition, if a method other than over building and cutting back to the compacted core is to be employed, slope compactiontestihg during construction should include testing the outer six inches to three feet in the slope face to determine if the required compaction is being achieved: Finish' grade testing of the slope should be performed after construction is complete. Each day the Contractor should receive a copy of the Soils Engineer's "Daily Field Engineering Report" which would indicate the results of field density tests that day. 9. Fill over cut slopes should be constructed in the following manner: All surficial soils and weathered rock materials should be removed at the cut-fill interface. A key at least 1. equipment width wide (see report) and tipped at least 1 foot into slope should be excavated Into competent materials and observed by the Soils Engineer or his representative. ' C) The cut portion of the slope should be constructed prior to fill placement to evaluate if stabilization is necessary, the contractor should be responsible for any additional earthwork created by placing fill prior, to cut excavation. 10. Transition lots (cut and fill) and lots above stabilization fills should be capped with a four foot thick compacted fill blanket (or as indicated in the report). 11.. Cut pads should be observed by the Geologist to evaluate the need for overexcavation and replacement with fill. This may be necessary to reduce water infiltration into highly fractured bedrock or other permeable zones, and/or due to differing expansive potential of materials beneath a structure. The overexcavation should be at least three feet. Deeper overexcavation may be recommended in some cases. 12. Exploratory backhoe or dozer trenches still remaining after site removal should be excavated and filled with compacted fill if they can be located. Grading Observation and Testing Observation of the fill placement should be provided by the Soils Engineer during the progress of grading. In general, density tests would be made at intervals not exceeding two feet of fill height or every 1,000 cubic yards of fill placed. This criteria will vary depending on soil conditions and the size of the fill. In any event, an adequate number of field density tests should be made to evaluate if the required compaction and moisture content is generally being obtained. ' Density tests may be made on the surface material to receive fill, as required by the Soils Engineer. (3) Cleanouts, processed ground to receive fill, key excavations, subdrains and r o c k d i s p o s a l should be observed-by the Soils Engineer prior to placing any fill. It will be the Contractor's responsibility to notify the Soils Engineer when such areas are ready for o b s e r v a t i o n . A Geologist should observe subdrain construction. A Geologist should observe benching prior to and during placement of fill . Utility Trench Backfill . Utility trench backfill should be placed to the following standards: Ninety percent of the laboratory standard if native material is used as bac k f i l l . As an alternative, clean sand may be utilized and flooded into place. No sp e c i f i c r e l a t i v e compaction would be required; however, observation, probing, and if d e e m e d n e c e s s a r y , testing-may be required. Exterior trenches, paralleling a footing and extending below a 1:1 plane p r o j e c t e d f r o m t h e outside bottom edge of the footing, should be compacted to 90 percent o f t h e l a b o r a t o r y standard. Sand backfill, unless it is similar to the inpiace fill, should not be a l l o w e d i n t h e s e trench backfill areas. Density testing along with probing should be accomplished to verify the des i r e d r e s u l t s . (4)