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1997-5018 G/CN/CS ~----~--~----- Street Address ~_L(Q~:L--- Category I 5;L(¿ l~ Serial # O¡{¡- Oq~ þJ1y J. MVP Name / Description Year Plan ck. # ~~^,..^""'" I I I I I ¡ I I I I I I I I I I I I I I ~II=- ~ .- -- - -- - ä:: A GTG Comp,"y Leighton and Associates GEOTECHNICAL CONSULTANTS FINAL AS-GRADED REPORT OF FINE AND POST GRADING, PROPOSED TACO BELL RESTAURANT, 815 BIRMINGHAM DRIVE, ENCINIT AS, CALIFORNIA Project No. 4971006-002 September 29, 1998 Prepared For Golden West Tacos, Inc. A Franchise of Taco Bell, Inc. P.O. Box 710699 Santee, California 92072 3934 MURPHY CANYON ROAD, SUITE 8205 SAN DIEGO, CA 92123-4425 (619) 292-8030 . FAX (619) 292-0771 I I I I I I I I I I I I I I I I I I I ~IiR=- ~ .- -- - -- -ä:: AGTGComp,"y Leighton and Associates GEOTECHNICAL CONSULTANTS September 29, 1998 Project No. 4971006-002 To: Golden West Tacos, Inc. A Franchise of Taco Bell, Inc. P.O. Box 710699 Santee, California 92072 Attention: Mr. Bill Mayeski Subject: Final As-Graded Report of Fine and Post Grading, Proposed Taco Bell Restaurant, 815 Birmingham Drive, Encinitas, California Introduction In accordance with your request and authorization, we have performed geotechnical observation and testing services during the fine and post-grading operations for the Taco Bell Restaurant located at 815 Birmingham Drive in Encinitas, California. The purpose of our geotechnical observation and testing services was to document that the fine and post-grading operations within the subject site were performed in accordance with the project geotechnical reports (Leighton, 1997a and 1997b), geotechnical recommendations made during the course of grading and the City of Encinitas requirements. This final as-graded report summarizes our geotechnical observations and field and laboratory test results on the fill soils associated with up to 5 feet of removal and recompaction of fill soils across the site, retaining wall construction and backfill, utility trench backfill and compaction operations; drive-thru and parking lot subgrade soil and Class 2 aggregate base placement and compaction, and asphalt concrete (A.C) placement in the parking lot. Portions of this report were previously summarized in the interim report dated August 8, 1997 (Leighton, 1997b). As of the date of this report, the post-grading operations of the subject site are essentially complete. 3934 MURPHY CANYON ROAD, SUITE 8205 SAN DIEGO, CA 92123-4425 (619) 292-8030 . FAX (619) 292-0771 I I I I I I I I I I I I I I I I I I I 4971006-002 Summarv of Gradine Operations . Fine Gradine: Fine grading operations were performed between July and August, 1997 and were discussed in our interim report of fine grading (Leighton, 1997b) and are briefly summarized herein. Fine grading of the subject property consisted of construction of a retaining wall around the east, south and west perimeter of the site and removal and recompaction of up to 5 feet below finished grade to achieve the design pad elevation. Once removed, the ground surface was scarified, moisture-conditioned as needed to obtain a near optimum moisture content, and fill soils were placed and recompacted to a minimum 90 percent relative compaction (based on ASTM Test Method D 1557-96) to the design pad elevation. Footing inspections and concrete testing were performed for the site retaining wall prior to fill placement in the drive-thru area. . Post Gradine: The post-grading operations began in September, 1997 and are essentially complete as of the date of this report. Post-grading operations completed during the development of the Taco Bell Restaurant included the following: 1) trench excavation and backfill compaction of sewer and joint utility lines; 2) drive-thru and parking lot subgrade soil preparation and compaction; and 3) Class 2 aggregate base material placement and compaction in the drive-thru and parking lot areas; and 4) asphalt concrete placement and compaction in the parking lot area. Compaction testing and observations were performed by representatives of our firm who were on site as-needed during post-grading operations. Specific observation and testing services conducted during the post-grading operations included the following: Field and Laboratorv Testine Field density tests were performed during the placement of compacted fill, trench backfill, subgrade preparation, placement of the crushed aggregate base material and asphalt concrete during fine- and post- grading operations of the site. Density tests were performed in accordance with the Nuclear-Gauge Method (ASTM Test Methods D2922-96 and D3017-96). The results and approximate locations of the field density tests performed are summarized in Appendix B. Areas in which field density tests were less than the required 90 or 95 percent relative compaction or were observed to be non-uniform, were reworked, recompacted, and retested until the minimum 90 or 95 percent relative compaction was achieved. In accordance with the City of Encinitas criteria, subgrade soils and Class 2 aggregate base material for the drive-thru and parking lot and A.C. for the parking lot were compacted to a minimum 95 percent of the maximum dry density as determined by ASTM Test Method DI557-96. -2- ::::::::01 ;:::: - ~ -~== ~ -.:: I I I I I I I I I I I I I I I I I I I 4971006-002 . Trench Excavations and Backfill Underground utilities, including sewer and common joint utilities were placed during the development of the site. Prior to backfilling of the utility trenches, the excavations were observed by a representative from our firm. Backfilling of the utility trenches was accomplished by compacting on site and import soils to a minimum 90 percent relative compaction (based on ASTM Test Method DI557-96). Testing frequency and locations were performed in general conformance with the City of Encinitas criteria. The results and approximate location of the backfill tests are summarized in Appendix B. . Structural Pavement Section Prior to placement of Class 2 aggregate base material, the subgrade soils were scarified to a minimum depth of 12 inches, moisture-conditioned to near-optimum moisture content and compacted to at least 95 percent relative compaction in the drive-thru and parking lot areas (based on ASTM Test Method DI557-96). The aggregate base material placed on the site was compacted to a minimum of95 percent of the maximum dry density (based on ASTM Test Method D1557-96). The results and approximate location of the subgrade soil and base material density tests are summarized in Appendix B. -3- ~'I-=.=: ~ -.:: I I I I I I I I I I I I I I I I I I I 4971006-002 Summarv of Conclusions Based on the results of our as-needed observation and testing at the site, we provide the following comments: 0 Geotechnical conditions encountered during fine and post grading were generally as anticipated. 0 Based on our observation and testing, fine- and post-grading operations were performed. in general accordance with the project geotechnical recommendations and the current City of Encinitas requirements. In our professional opinion, the geotechnical aspects of the development have been evaluated and properly treated during fine and post grading. 0 Field density testing indicated that the fill soils and trench backfill soils on the site were compacted to a minimum 90 percent relative compaction (based on ASTM Test Method DI557-96). Field density testing also indicated that the drive-thru and parking lot sub grade and base materials, and A.C. in the parking lot area were compacted to a minimum of 95 percent relative compaction (based on ASTM Test Method DI557-96). If you have any questions regarding our report, please do not hesitate to contact this office. We appreciate this opportunity to be of service. Respectfully submitted Attachments: Appendix A - References Appendix B - Summary of Field Density Tests Appendix C - Laboratory Testing Procedures and Test Results LEIGHTON AND ASSOCIATES, INC. ~~ Michael R. Stewart, . G 1349 (Exp. ~ ~ Director of Geology ,') \.~--':"~C': ') (:)'./'.;.\..I-"i.-ì.:'.~.~~ «;- ¡"" ,. ~/ ~ ICJ "... Ú'. -, ~ .... \' .¿- No. 1349 ~i \ * CERTIFIED 'I ENGIII::r:R:.~J . ~) If\ C;;E.UL' (J': '. - I r' ~Y'-I -' ~ "'1" / .', / .~. .. ü\,- , (. .. .,- .. OF CAl\~')d ~ KBCIMRS Distribution: (2) Addressee (1) Cal Select Builders Attention: Mr. Ken Shafer P:Projects/971006.002/Finai As-grd -4- --01 ;:::: ~ -- ~ -~::::. ~ -.:: ~IR=- ~ .- -- - -- -ä:: A GTG Comp>cy Leighton and Associates GEOTECHNICAL CONSULTANTS TRANSMITT AL To: Golden West Tacos, Inc. A Franchise of Taco Bell, Inc. P.O. Box 710699 Santee, California 92072 Date: September 29, 1998 Project No. 4971006-002 Attention: Mr. Bill Golterman Transmitted: Courier The Following: Draft Report ~ Final Report For: ~ MaillUPS x Your Use As Requested _PickUp - Extra Report - Proposal Other Subject: Final As-Graded Report of Fine and Post Grading:. Proposed Taco Bell Restaurant. 815 Birmingham Drive. Encinitas. California LEIGHTON AND ASSOCIATES, INC. By: Michael R. Stewart Copies: (1) Cal Select Builders Attention: Mr. Ken Shafer 3934 MURPHY CANYON ROAD, SUITE 8205 SAN DIEGO, CA 92123-4425 (619) 292-8030 . FAX (619) 292-0771 I I I I I I I II I I I I I I I I I I I 4971006-002 APPENDIX A REFERENCES Leighton and Associates, Inc., 1997a, Geotechnical Investigation, Proposed Taco Bell Restaurant, 815 Birmingham Drive, Encinitas, California, Project No. 4871006-001, dated January 17, 1997. ) 1997b, Interim Report of Fine Grading, Proposed Taco Bell Restaurant, 815 Birmingham Drive, Encinitas, California, Project No. 4871006-002, dated August 8, 1997. Golden West Tacos, Inc., 1996, Grading Plans for: Taco Bell Birmingham Drive Encinitas, California, sheets AlA, AIB, AIC, scale: 1" = 20', dated December 9,1996. A-I - - - - 09/29/98 PROJECT NUMBER: 04-971006-02 NAME: TACO BELL TEST TEST TEST TEST NUMBER METH DATE OF _u_---u - -- - u----u -- -- 1 N 07/30/97 CF 2 N 07/30/97 CF 3 N 07/30/97 CF 4 N 07/30/97 CF 5 N 07/30/97 CF 6 N 07/31/97 CF 7 N 07/31/97 FG 8 N 07/31/97 CF 9 N 07/31/97 CF - - - - - - - - - - - - - - - SUMMARY OF FIELD DENSITY TESTS ------------ LOCATION -------------- TEST SOIL DRY DENSITY(pcf) MOISTURE(%) REL(%) REMARKS ELEV(ft) TYPE FIELD MAX FIELD OPT CaMP ------------------------------------ --_u_u-- u - - -----_hUh u_--u_--- ----- ---u_---- BUILDING PAD 272.0 1 113.7 118.0 9.2 12.0 96 BUILDING PAD 272.0 1 114.2 118.0 14.9 12.0 97 BUILDING PAD 273.0 1 114.3 118.0 12.2 12.0 97 DRIVE THRU 274.0 1 113.4 118.0 12.2 12.0 96 BUILDING PAD 274.0 1 109.7 118.0 12.2 12.0 93 BUILDING PAD 275.0 1 108.9 118.0 11.0 12.0 92 BUILDING PAD 276.0 1 109.9 118.0 12.0 12.0 93 DRIVE THRU 274.0 1 112.1 118.0 10.9 12.0 95 DRIVE THRU 273.0 1 106.0 118.0 8.2 12.0 90 - - - - - - - - - - - - - - - - - - - 09/29/98 SUMMARY OF FIELD DENSITY TESTS PROJECT NUMBER: 04-971006-02 NAME: TACO BELL TEST TEST TEST TEST ------------ LOCATION -------------- TEST SOIL DRY DENSITY(pcf) MOISTURE(%) REL(%) REMARKS NUMBER METH DATE OF ELEV(ft) TYPE FIELD MAX FIELD OPT COMP --------- ---- -------- -- - - ------------------------------------ ---------- -- - - ------------ ----------- ----- ---------- SG 1 N 07/31/97 D DRIVE THRU 0.0 1 113.7 118.0 4.8 12.0 96 SG 2 N 08/05/97 D DRIVE THRU 0.0 1 115.0 118.0 6.4 12.0 97 SG 3 N 08/05/97 D DRIVE THRU 0.0 1 114.1 118.0 7.3 12.0 97 SG 4 N 08/05/97 D DRIVE THRU 0.0 1 114.4 118.0 10.0 12.0 97 SG 5 N 10/08/97 D DRIVE THRU 0.0 1 112.3 118.0 8.3 12.0 95 SG 6 N 10/08/97 D DRIVE THRU 0.0 1 108.9 118.0 9.4 12.0 92 RT ON 6A SG 6A N 10/09/97 D DRIVE THRU 0.0 1 112.3 118.0 9.9 12.0 95 RT OF 6 SG 7 N 10/08/97 D DRIVE THRU 0.0 1 106.7 118.0 9.6 12.0 90 RT ON 7A SG 7A N 10/09/97 D DRIVE THRU 0.0 1 114.0 118.0 10.2 12.0 97 RT OF 7 SG 8 N 10/09/97 D DRIVE THRU 0.0 1 107.6 118.0 10.2 12.0 91 RT ON 8A SG 8A N 10/09/97 D DRIVE THRU 0.0 1 111.9 118.0 10.5 12.0 95 RT OF 8 SG 9 N 11/04/97 PL N. PARKING LOT N. SIDE 0.0 1 106.2 118.0 7.9 12.0 90 RT ON 9A SG 9A N 11/04/97 PL N. PARKING LOT 0.0 1 114.3 118.0 9.9 12.0 97 RT OF 9 SG 10 N 11/04/97 PL N. PARKING LOT NORTH SIDE 0.0 1 104.9 118.0 7.0 12.0 89 RT ON 10A SG 10A N 11/04/97 PL N. PARKING LOT 0.0 1 115.0 118.0 10.6 12.0 97 RT OF 10 SG 11 N 11/04/97 PL S.E. CORNER OF OF PARKING LOT 0.0 1 109.2 118.0 8.9 12.0 93 RT ON 11A SG 11A N 11/04/97 PL N. PARKING LOT 0.0 1 115.9 118.0 8.1 12.0 98 RT OF 11 SG 12 N 11/04/97 PL S.II. CORNER OF OF PARKING LOT 0.0 1 115.1 118.0 10.2 12.0 98 - - - - - - - - - - - - - - - - - - - 09/29/98 PROJECT NUMBER: 04-971006-02 NAME: TACO BELL TEST TEST TEST TEST NUMBER METH DATE OF -------u - - -- -----n- u-- S 1 N 09/08/97 S S 1A N 09/08/97 S S 2 N 09/08/97 S S 3 N 09/08/97 S S 4 N 09/08/97 s SUMMARY OF FIELD DENSITY TESTS ------------ LOCATION -------------- TEST SOIL DRY DENSITY(pcf) MOISTURE(%) REL (%) REMARKS ELEV(ft) TYPE FIELD MAX FIELD OPT COMP ------------------------------------ ---U--n- -- - - -------U--- ------n_-- ----- ---U_---- S.E. OF STRUCTURE -1.0 1 100.4 118.0 7-1 0.0 85 RT ON 1A S.E. OF STRUCTURE -1.0 1 106.2 118.0 8.3 0.0 90 RT OF 1 S.E. OF STRUCTURE -1.5 1 112.1 118.0 7.2 0.0 95 S.E. OF STRUCTURE 0.0 1 111 .9 118.0 7.7 0.0 95 S.E. OF STRUCTURE -5.0 1 108.8 118.0 13.2 0.0 92 - - - - - - - - - - - - - - - - - - - 09/29/98 SUMMARY OF FIELD DENSITY TESTS PROJECT NUMBER: 04-971006-02 NAME: TACO BELL TEST TEST TEST TEST ------------ LOCATION -------------- TEST SOIL DRY DENSITY(pcf) MOISTURE(%) REL(%) REMARKS NUMBER METH DATE OF ELEV( ft) TYPE FIELD MAX FIELD OPT COMP _-_--_00- - --- -------- -- -- ------------------------------------ _0000_---- 00-- --00_000000- --00_0000-- 0000- ---------- JT 1 N 09/08/97 JT N.E. OF STRUCTURE -2.0 1 100.3 118.0 8.9 0.0 85 RT ON 1A JT 1A N 09/10/97 JT N.E. OF STRUCTURE -2.0 1 103.8 118.0 10.6 0.0 88 RT OF 1 JT 1B N 09/11/97 JT N.E. OF STRUCTURE -2.0 1 112.8 118.0 12.9 0.0 96 RT OF 1A JT 2 N 09/10/97 JT N.E. OF STRUCTURE -2.0 1 106.2 118.0 10.9 0.0 90 JT 3 N 09/10/97 JT N.E. OF STRUCTURE -1.0 1 105.2 118.0 17.6 0.0 89 RT ON 3A JT 3A N 09/11/97 JT N.E. OF STRUCTURE -1.0 1 106.2 118.0 14.1 0.0 90 RT OF 3 JT 4 N 09/11/97 JT N.E. OF STRUCTURE -2.5 1 115.2 118.0 9.1 0.0 98 JT 5 N 09/11/97 JT N.E. OF STRUCTURE -2.0 1 107.2 118.0 12.7 0.0 91 JT 6 N 09/12/97 JT N.E. OF STRUCTURE 0.0 1 113.3 118.0 7.4 0.0 96 JT 7 N 09/12/97 JT N.E. OF STRUCTURE 0.0 1 107.4 118.0 6.2 0.0 91 JT 8 N 09/16/98 JT E. OF STRUCTURE -1.0 1 109.7 118.0 7.9 0.0 93 JT 9 N 09/16/98 JT E. OF STRUCTURE -1.0 1 106.9 118.0 9.7 0.0 91 JT 10 N 09/16/98 JT N.E. OF STRUCTURE -1.0 1 108.6 118.0 9.8 0.0 92 JT 11 N 09/16/98 JT N.E. OF STRUCTURE -1.0 1 106.3 118.0 11.2 0.0 90 - - - - - - - - - - - - - - - - - - - 09/29/98 SUMMARY OF FIELD DENSITY TESTS PROJECT NUMBER: 04-971006-02 NAME: TACO BELL TEST TEST TEST TEST ------------ LOCATION -------------- TEST SOIL DRY DENSITY(pcf) MOISTURE(%) REL(%) REMARKS NUMBER METH DATE OF ELEV(ft) TYPE FIELD MAX FIELD OPT COMP --------- ---- -_----n n - - ------------------------------------ ---------- - n - _n__------- --n__----- - - -- - ------_n- AB 1 N 10/16/97 D DRIVE THRU 0.0 2 130.5 136.0 7.5 6.0 96 AB 2 N 10/16/97 D DRIVE THRU 0.0 2 133.2 136.0 7.6 6.0 98 AB 3 N 10/16/97 D DRIVE THRU 0.0 2 130.5 136.0 7.3 6.0 96 AB 4 N 10/16/97 D DRIVE THRU 0.0 2 131.5 136.0 6.4 6.0 97 AB 5 N 10/16/97 D DRIVE THRU 0.0 2 129.5 136.0 6.7 6.0 95 AB 6 N 10/16/97 D DRIVE THRU 0.0 2 130.3 136.0 7.1 6.0 96 AB 7 N 11/05/97 PL PARKING LOT 0.0 2 124.2 136.0 9.8 6.0 91 RT ON 7A AB 7A N 11/05/97 PL PARKING LOT 0.0 2 128.5 136.0 7.8 6.0 94 RT OF 7 AB 8 N 11/05/97 PL PARKING LOT 0.0 2 124.2 136.0 9.9 6.0 91 RT ON 8A AB 8A N 11/05/97 PL PARKING LOT 0.0 2 130.1 136.0 7.1 6.0 96 RT OF 8 AB 9 N 11/05/97 PL PARKING LOT 0.0 2 121.9 136.0 9.1 6.0 90 RT ON 9A AB 9A N 11/05/97 PL PARKING LOT 0.0 2 133.0 136.0 6.2 6.0 98 RT OF 9 AB 10 N 11/05/97 PL PARKING LOT 0.0 2 127.4 136.0 7.6 6.0 94 AB 11 N 11/05/97 PL PARKING LOT 0.0 2 127.0 136.0 7.2 6.0 93 AB 12 N 11/05/97 PL PARKING LOT 0.0 2 128.2 136.0 7.9 6.0 94 - - - - - - - - - - - - - - - - - - - 09129/98 SUMMARY OF FIELD DENSITY TESTS PROJECT NUMBER: 04-971006-02 NAME: TACO BELL TEST TEST TEST TEST ------------ LOCATION -------------- TEST SOIL DRY DENSITY(pcf) MOl STURE (%) REL(%) REMARKS NUMBER METH DATE OF ELEV(ft) TYPE FIELD MAX FIELD OPT COMP --------- ---- -------- -- - - ------------------------------------ ---------- ---- ----_u----- u--------- ----- ---------- AC 1 N 11/05/97 PL SOUTH OF ISLAND 0.0 AC1 139.0 152.0 0.0 0.0 91 RT ON 1A AC 1A N 11/05/97 PL SOUTH OF ISLAND 0.0 AC1 147.0 152.0 0.0 0.0 97 RT OF 1 AC 2 N 11/05/97 PL SOUTH OF ISLAND 0.0 AC1 141.0 152.0 0.0 0.0 93 RT ON 2A AC 2A N 11/05/97 PL SOUTH OF ISLAND 0.0 AC1 149.0 152.0 0.0 0.0 98 RT OF 2 AC 3 N 11/05/97 PL WEST OF ISLAND 0.0 AC1 145.0 152.0 0.0 0.0 95 AC 4 N 11/05/97 PL SOUTH OF ISLAND 0.0 AC1 144.9 152.0 0.0 0.0 95 AC 5 N 11/05/97 PL WEST OF ISLAND 0.0 AC1 144.6 152.0 0.0 0.0 95 AC 6 N 11/05/97 PL EAST OF ISLAND 0.0 AC1 145.1 152.0 0.0 0.0 95 AC 7 N 11/05/97 PL NORTH OF ISLAND 0.0 AC1 145.0 152.0 0.0 0.0 95 AC 8 N 11/05/97 PL NORTH OF ISLAND 0.0 AC1 146.2 152.0 0.0 0.0 96 AC 9 N 11/05/97 PL JOINT TRENCH AREA 0.0 AC1 144.5 152.0 0.0 0.0 95 AC 10 N 11/05/97 PL JOINT TRENCH AREA 0.0 AC1 144.6 152.0 0.0 0.0 95 I I I I I I I I I I I I I I I I I I I 4971006-002 APPENDIX C Laboratory Testing Procedures and Test Results Maximum Density Tests: The maximum dry density and optimum moisture content of typical materials were determined in accordance with ASTM Test Method D1557. The results of these tests are presented in the table below: Maximum Dry Optimum Moisture Sample Location Sample Description Density (pet) Content (%) 1 Yellow brown, silty sand 118.0 12.0 2 Class II Aggregate Base 136.0 6.0 C-l .. ~ N AC:IL~~IN~E~G' ~U~E~:' ~N: p~N~LN G 196-058.1 CITY OF ENCINIT AS 505 S. Vulcan Ave. Encinitas, CA 92024-3633 5/29/97 f7\o '\.( íi\J Œ"c. ii. \\[7 !'.:'.:;~. ! J (~ ! III ,J I : \ ¡ i l" t .:. I pC<. ,.j <.::.J L.J -- U LJLJ JUN 06 1991 ENGiNEEFLNG SERV:CEC CiTY OF ENC1NJTf\S Subject: Hydraulic Analysis for Taco Bell Site Located at the South side of Binning ham Dr., East of the 1-5 Frwy. Encinitas, California Introduction / Basis of Analysis The Hydraulic Analysis utilized in this study is based on Manning's equation, and Autocad/Softdesk software was used for hydraulic calculations. Proposed flow was calculated using the Rational Method as described in the San Diego County Design and Procedure Manual. The attached Hydrology Map (see Exhibit 'A') shows the watershed area (0.52 acres) and drainage patterns of proposed conditions. The runoff coefficient was assumed to be C=.9 (mostly impervious concrete / asphalt). Based on a 100 year storm, the rainfall intensity was detennined to be 4.2 (see shts 5/8 - 8/8). The proposed site drains into a catch basin located on the southwest comer of the property, then into a concrete Brow Ditch (see Exhibit 'A'). Calculations (see sheets 2/8 - 4/8) Q(atPo'O.C.) = CIA = (0.9) x (4.2 in/hr) x (0.52 acres) = 1.9 cfs ... say 2.0 cfs - For 12" pipe at 1%: Qmax= 3.83 cfs 2 cfs < 3.83 cfs - For Type 'A' Brow Ditch (see sht 4/8): For Q = 2 cfs, Depth offlow = 4" 4" < 12" Conclusion The 12" diameter pipe sloped at 1%, and the concrete V-ditch sloped at 62% will be sufficient to carry the proposed runoff of a 100 year storm. Sht. 1/9 3359 Chicago Avenue, Riverside, California 92507 . 909-784-3300 . FAX 909-784-3368 Manning Pipe Calculator Gi en Input Da~~: Shape ........................... Solving for ..................... Diameter ........................ Flow-rate ........................ Slope ........................... Manning's n ..................... C=m.uted Results: Depth ........................... Area ............................ r"¡etted Area ..................... Wet~ed Perimeter... ... .......... Perimeter ....................... Velocity........................ Hydraulic Radius .. ......... ..... Percent Full.................... Full flew :lowra~e . ............. Full flow velocity.............. Circular Depth of Flew 12.0000 in 3.3320 cis'; 0.0100 ft/:-: 0.0130 11.2058 in/ 0.7854 it:: 0.7632 f~2 31.4546 in 37.6991 i:1 5.0213 ips 3.4937 in 93.3817 % 3.5628 cfs 4.5363 ips Critical I:1fo~ation Critical depth.................. 136.733~ in Critical slope.................. 0.0100 ft/ft Critical velocity............... 26.0675 ips Critical area............... .... 110.9541 f-:2 Critical perimeter.............. 387.1367 in Critical hydraulic radius....... 41.2707 in Critical top width.............. 63.0423 in Specific energy................. 21.9705 it Minimum energy.................. 17.0917 it Froude number ................... 1.0812 Flow cendition ...... .... ........ Supercri-:ical /- ~""\ / : - II . II )\ 10' .to i \ I \ \ "', / '",--- t / T- , I i I 0- J': 1/ - I ~ I I I I 'I' /J: /2 ,. Q-"'r</" ,. -J.Cjc;: <: /" )0 ; / i ¡J: . C /3 d. II " " - I' :::. (fOL'/lAl6 FeR QmClX) // f"CI? /2. /I ø r? I 1. 5 Ion Manning Pipe Calculat~r Gi en Input Data~ Shape ........................... Solving for ..................... Diameter ........................ Flowrate ........................ Slope ........................... Manning's n ..................... Co puted Results: Depth ........................... Area ............................ Wetted Area ..................... Wetted Perimeter... ............. Perimeter ....................... Velocity........................ Hydraulic Radius ... ... ... ....... Percent Full.................... F~¡: ~:cw F:ow:a~e . .... ..... .... Full flow velocity........... ... Critical In~o~a~:~n C:itica: dept~ ..... ........ ..... Critical slope .................. C:itical velocity. .......... .... C:itica: area ................... C:itical perimeter. ... ..... ..... Critical hydraulic :adius .... ... Critical top width. ... .... ...... Specific energy................. Minimum energy. .......... ....... Froude number...... ...... .... ... Flow c~ndition .... ....... ....... Ci:.-cular Depth of Flow 12.0000 in 2.0000 cfs 0.0100 ft/ft 0.0130 6.4304 in ~ 0.7854 ft2 0.4285 ft2 19.7110 in 37.6991 in 4.6671 ips 3.1307 in 53.5865 % 3.5623 c:s 4.5363 ips 107.3896 i:-: 0.0038 f':/:': 16.6881 ips 90.4566 ft2 300.1872 i:-: 43.3921 in 125.4046 in 15.7300 f': 13.4237 f': 1.8993 Supercritical ~" t / I ! I ! - , - -,/ Å I ;"'.::.. i ¡ J. \ ~id: G...L" \ i \ I I I r '7: /:;o" 1- - Q: 2 c!: 5, ; i 1. 17~.C/3 d : 6.4-" - - (50:"11/'/(, f"C/f OEPTf/. OF F LON) Channel Calculator Giv n Input Data: Shape ........................... Solving for ..................... Flowrate ........................ Slope ........................... Manning's n ..................... Height .......................... Bottom width. . . . . . . . . . . . . . . . . . . . Left slope...................... Right slope..................... Corn uted Results: Depth. . . . . . . . . . . . . . . . . . . . . . . . . . . Velocity. . . . . . . . . . . . . . . . . . . . . . . . Flow area....................... Flow perimeter ..... ............. Hydraulic radius .... ............ Top width....................... Area ............................ Perimeter. . . . . . . . . . . . . . . . . . . . . . . Percent full....... ........ ..... ,-1/ 12n. - - n -- -.n- ___o'o'-j-- u_. .~ ~ \ ~ fi'\. I r\ 'o' '\. \~ " '\ " Ä "~ '/--- - ~ 'y Trapezoidal / Depth of Flowv 2.0000 cis 0.6200 it/it 0.0120 12.0000 in 0.0000 in 0.8000 it/it 0.8000 it/it 4.0631 in'! 21.8062 ips 0.0917 ft2 10.4067 in 1.2691 in 6.5010 in 0.8000 ft2 30.7350 in 33.8595 % .; ~ /5 /1 ~ " v i I ~' ~ ~ /VOJ ftJ jtA1-: @ Q:2J::i.: n L " jo='c.:.. n. Of? I I - , ,- --.-. L/[,/?-r)'i 0 r ,t:;o'r</ A II - -- , , , , é ~ ~ , , - ~ '-,- 1~ 78~ ,~'.;¡" I 3:-""" '" . ---- / <'>9 1/1 \277--DAAJNAGE BA~ '/ - 0.52 l.:('J:H:! <> ~ / ~~ I III~ " ;i . l' 1: P~"""'-- ~~ TACO sE1i. 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Revised 1/35 AP?::\:J::{ X:-;' cOUnTY OF SA" D Irr.n DE PART/tnn OF SAil ITAT IOU & fI OOD (m/TROl .'u.-.. 1..".1 1.-I.lInIDI,.I .-it"I.". .1',"'.. ,.,. S.JII:'~' . fREC II Z' 2..6 1/ , 15' :. I 338 ;u I1Þ -< ,.. UI I1Þ A. .... "- (.0 UI ltSI - P..p.f..... ?,; "0 In "/. a u.s. DEPARTt.1EMr OF CmtMEHCI-: ""-110""-1- OCt:ANIC ANI> AI't"SI"II:HIC Allatt:-uSU!ATIOII SI'a:CIAL STUUIICS ""ANl"lI. .. t flCI: () I' II 111"11~')(¡V. IIA II""AI~ IIIt.AIIIU! St IIVIC£ ~. :-< )01 -.-- .1 x to'O I III lIB' '151 -1- )01 liS' 1168 15 I )()' I S I Ih:vhc.1 1/85 AI'I'Hml X X 1 I: 5D\g-~ LEIGHTON AND ASSOCIA TES, INC. Geotechnical and Environmental Engineering Consuhants i' ~-~ OJ Ie' (-" '. í Io'~ Ii - I.; i . '.. c GEOTECHNICAL INV~STIGAT JiJ, L~ .~;; L; i", ¡ II ¡ PROPOSED TACO BELL RESTAURANTMAR 05 1997 L~:..,' 815 BIRMINGHAM DRIVE, ENGIN ~ ENCINITAS, CALIFORNIA CI-riERING SERViCES OF ENCINITAS January 17, 1997 Project No. 4971006-001 Prepared For: GOLDEN WEST TACOS, INC. A Franchise of Taco Bell, Inc. P.O. Box 710699 Santee, California 92072 3934 MURPHY CANYON ROAD, SUITE B20S, SAN DIEGO, CA 92123 (619) 292-8030 . (800) 447-2626 FAX (619) 292-0n I LEIGHTON AND ASSOCIA TES, INC. Geotechnical and Environmental Engineering Consuhants January 17, 1997 Project No. 4971006-00 I To: Golden West Tacos, Inc. A Franchise of Taco Bell, Inc. P.O. Box 710699 Santee, California 92072 ,- Attention: Mr. Bill Mayeski Subject: Geotechnical Investigation, Proposed Taco Bell Restaurant, 815 Birmingham Drive, Encinitas, California In accordance with your request and authorization, we have performed a geotechnical investigation for the proposed development. The accompanying report presents a summary of our investigation and provides geotechnical conclusions and recommendations relative to the proposed site development. ~ Based on the results of our investigation and review of the current preliminary plans provided by Golden West Tacos, Inc., the proposed development is considered feasible &om a geotechnical standpoint provided the recommendations outlined in this report are implemented during site grading and construction. If you have any questions regarding our report, please contact this office. We appreciate this opportunity to be of service. LEIGHTON AND ASSOCIATES, INC. 5tc17Z- ~~ Scott C. Burns Senior. Staff Engineer, RCE 55370 ~ck ose G. Franzone, RCE 39552 . rector of Engineering , Respectfully submitted, Michael R. Stewart, Director of Geology Distribution: (4) Addressee SCB/JGF IMRSlkar 3934 MURPHY CANYON ROAD. SUITE B205. SAN DIEGO, CA 92123 4971006-001 1.0 !NTRODUCTION 1.1 Purpose and Scope This report presents the results of our geotechnical investigation for the proposed Taco Bell Restaurant located at 815 Birmingham Drive, Encinitas, California. The purpose of our investigation was to evaluate the geotechnical conditions at the site and to provide conclusions and recommendations relative to site development. The scope of our services during the investigation included the following: . Review of geotechnical literature pertaining to the general area of the site and geotechnical reports pertaining specifically to the site. A list of the items reviewed is included in Appendix A. . Field reconnaissance of the site and general vicinity. . Subsurface exploration consisting of the excavation, logging and sampling of 3 exploratory borings to a maximum depth of 20 feet below existing grade. Logs of the borings are presented in Appendix B. . Laboratory testing of representative soil samples obtained during the subsurface exploration to evaluate their pertinent engineering characteristics. Results of the laboratory tests are provided in Appendix C. . Geotechnical analysis of the data obtained. . Preparation of this report presenting our findings, conclusions, and recommendations with respect to the proposed development. 1.2 Site Description The site is located southeast of the Interstate 5 and Birmingham Drive intersection, Encinitas, California. Currently the site is occupied by a restaurant with asphalt parking and driveway areas. A retaining wall is situated around the east, south and western perimeter of the site. In addition, the site is flanked by a downward trending, 16 foot high slope to the south and west with a retaining structure along the south toe of the slope. Topographically, the site slopes gently downward toward the south with elevations ranging from 282 to 273 feet mean sea level (MSL). Vegetation consists of a few mature trees in planter areas and ground cover on the slope surface. - 1 - 4971006-001 !.3 Proposed Dev~lopme:1t Based on our review of the preliminary 20-scale projects plans provided by Golden West Tacos, Inc. dated December 9, 1996, we understand that the proposed development will consist of a one- story Taco Bell restaurant with an approximate footprint area of 2,314 square feet. We anticipate the structure to be wood-framed and founded on a reinforced concrete slab on grade floor at an elevation of 276.8 feet. Other improvements include a retaining wall around the western and southern perimeter of the drive-thru lane, and associated driveway and parking areas. Minor grading is anticipated he import of soil required to raise the finished pad elevation approximately 2 feet etáinin w t the tops of existing slopes are to be removed and replaced as part of the new site evelfpment plans. { o~ .ç:t..A~. GA- (..L -11 "" ,.. - 2- 4971006-001 2.0 SUBSURFACE INVESTIGATION AND LABORATORY TESTING Our subsurface investigation at the site consisted of the excavation of 3 exploratory borings to a maximum depth of approximately 20 feet below existing grade. The borings were logged by a representative of our firm. The approximate locations of all borings are depicted on the Boring Location Map (Figure 2). Logs of the borings are presented in Appendix B. Subsequent to logging and sampling the borings were backfilled. ~ Appropriate laboratory testing was performed on representative soils collected during our subsurface investigation. The laboratory testing included inplace moisture and density, hydrocollapse potential, expansion potential, and soluble sulfate content. Brief descriptions of the laboratory test procedures and the laboratory test results are presented in Appendix C. - 3 - 4971006-001 3.0 SUMMARY OF GEOTECHNICAL CONDITIONS 3.1 Site Geology As encountered during our investigation, the site is underlain by formational units consisting of Terrace Deposits and fill soils. Descriptions of these units are presented below. 3.1.1 Terrace Deposits Quaternary-aged Terrace Deposits locally underlie the site. The Terrace Deposits were encountered at a depth of approximately 1 feet belúw ground surface (bgs) along the eastern half of the site and approximately 10 feet bgs along the western half of the site. As encountered during our investigation, these deposits generally consist of orange-red brown, dense, silty fine- to medium-grained sandstone. Laboratory test results (Appendix C) indicate a very low potential for hydrocollapse upon wetting. 3.1.2 Undocumented Fill Undocumented fill overlies the Terrace Deposits at the site with an approximate thickness of 2 feet over the eastern half of the site and increasing to a minimum of 10 feet over the western half of the site. These soils consist of tan-brown, damp, medium dense to dense silty sands. Laboratory test results (Appendix C), indicate a very low potential for hydrocollapse upon wetting and a very low expansion potential. 3.2 GroundWater Ground water was not encountered during our field study. Accordingly, we do not anticipate ground water to be a constraint to near surface improvements. However, localized seeps may be encountered during the wet season or as a result of irrigation leaks. 3.3 Faultinl:!: and Seismicity Our discussion of faults on the site is prefaced with a discussion of California legislation and state policies concerning the classification and land-use criteria associated with faults. By definition of the California Mining and Geology Board, an active fault is a fault which has had surface displacement within Holocene time (about the last 11,000 years). The State Geologist has defined a POtentiallv active fault as any fault considered to have been active during Quaternary time (last 1,600,000 years). This definition is used in delineating Special Studies Zones as mandated by the Alquist-Priolo Geologic Hazards Zones Act of 1972 and as subsequently revised in 1975, 1985, 1990, and 1992 (Hart, 1992). The intent of this act is to assure that unwise urban development does not occur across the traces of active faults. The subject site is not located within any special study zones as created by the Alquist-Priolo Act. - 4- 4971006-001 Our review of availab1~ gto[úgic 1iLtl'b.ture ifJdi<.:âted that there are ílO knowll active ùl pot~Uí:ially active faults that transect the subject site. Evidence of faulting on site was not encountered during our investigation. The location of the proposed development can be considered to lie within a seismically active region, as can all of Southern California. The Rose Canyon fault zone which is located approximately 3.7 miles to the west of the site is considered to have the most significant effect at the site from a design standpoint. A maximum probable earthquake of Richter Magnitude of 5.9 on the fault could produce a peak horizontal ground acceleration of approximately 0.33g at the site (Blake, 1995). . 3.4 Seismic Considerations The principal seismic considerations for most structures in Southern California are surface rupturing of fault traces, damage caused by ground shaking or seismically induced ground settlement. The probability of damage due to ground rupture is considered minimal since active faults are not known to cross the site. Lurching due to shaking from distant seismic events is not considered a significant hazard, although it is a possibility throughout the Southern California region. . Ground Shaking The seismic hazard most likely to impact the site is ground shaking resulting from an earthquake on one of the major regional faults. As discussed above, a maximum probable event of the Rose Canyon fault zone (considered the design earthquake for this site) could produce a peak horizontal ground acceleration at the site of 0.33g. The effects of seismic shaking can be reduced by adhering to the most recent edition of the Uniform Building Code and the design parameters of the Structural Engineers Association of California. ~ . Liauefaction Liquefaction of cohesionless soils can be caused by strong vibratory motion due to earthquakes. Research and historical data indicate that loose granular soils underlain by a near-surface ground water table are most susceptible to liquefaction, while the stability of most silty clays and clays is not adversely affected by vibratory motion. Due to the high density of the onsite Terrace Deposits and fill soils, the potential for liquefaction and dynamic settlement at the site due to the design earthquake is anticipated to be low. - 5 - 4971006-00 I 4.0 CO;-";CLUSrONS Based on the results of our geotechnical investigation, it our opinion that the proposed development is feasible from a geotechnical standpoint provided the following conclusions and recommendations are incorporated into the design and construction of the subject project. The following is a summary of the geotechnical factors which may affect development of the site. . Based on our subsurface exploration and review of pertinent geotechnical reports, the site is underlain by Terrace Deposits and undocumented fill soils. . A transition condition appears to exist at the site with shallow fill soils and near-surface formational materials on the eastern half of the site and thicker fill materials on the western half of the site. Grading remediation will be necessary. . Laboratory test results and our previous experience in the area indicate the soils present on the site have the following soil engineering characteristics: - very low to low expansion potential - negligible sulfate content - high shear strength . The existing onsite soils appear to be suitable for use as fill material provided they are free of organic material, debris, and rock fragments larger than 6 inches in maximum dimension. . Active or potentially active faults are not known to exist on the site. . The maximum anticipated ground acceleration on the site due to the design earthquake on the Rose Canyon fault zone of Richter Magnitude 5.9 is estimated to be O.33g. . Based on our evaluation, the potential for liquefaction and associated dynamic settlement at the site due to the design earthquake event is considered low. - 6 - 4971006-001 5.0 RECO~ÆMENDATIONS 5.1 Earthwork We anticipate that earthwork at the site will consist of site preparation, excavation, and backfill. We recommend that earthwork on the site be performed in accordance with the following recommendations and the General Earthwork and Grading Specifications included in Appendix D. In case of conflict, the following recommendations shall supersede those in Appendix D. 5.1.1 Site Preparation Prior to grading, all areas to receive structural fill or engineered structures should be cleared of surface and subsurface obstructions, including any existing debris, utilities, asphalt and existing foundations/footings, aild stripped of vegetation. Removed vegetation and debris should be properly disposed of off site. Holes resulting from removal of buried obstructions which extend below finished site grades should be replaced with suitable compacted fill material. All areas to receive fill and/or other surface improvements should be scarified to a minimum depth of 6 inches, brought to near optimum moisture condition, and recompacted to at least 90 percent relative compaction (based on ASTM Test Method D1557-9l). 5.1.2 Excavations Excavations of the onsite materials may generally be accomplished with conventional heavy-duty earthwork equipment. It is not anticipated that oversized rock (i.e. rock with maximum dimensions greater th~ 6 inches) will be generated during grading. However, if oversized rock is encountered, it should be placed as fill in accordance with the details presented in Appendix D. Due to the relatively high density characteristics and coarse nature of the onsite soils, temporary excavations such as utility trenches with vertical sides in the onsite soils should remain stable for the period required to construct the utility, provided they are free of adverse geologic conditions. However, in accordance with OSHA requirements, excavations deeper that 5 feet should be shored or laid back to inclinations of 1: 1 (horizontal to vertical) if workers are to enter such excavations. 5.1.3 Fill Placement and Compaction The onsite soils are generally suitable for use as compacted fill provided they are free of organic material, debris, and rock fragments larger than 6 inches in maximum dimension. All fill soils should be brought to near-optimum moisture conditions and compacted to uniform lifts to at least 90 percent relative compaction based on laboratory standard ASTM Test Method D1557-91. The optimum lift thickness required to produce a uniformly - 7 - 4971006-001 compnctcd fill will dcpcad on the type and size of compaction equipment used. In general, fill should be placed in lifts not exceeding 8 inches in thickness. Placement and compaction of fill should be performed in general accordance with the current City of Encinitas grading ordinances, sound construction practice, and the General Earthwork and Grading Specifications for Rough Grading presented in Appendix D. 5.2 Removal and Recompaction As indicated in our boring logs, a differential thickness of fill soils exists on site. Due to the presence of the existing restaurant and asphalt concrete, we were unable to determine the exact location of the transition between formational material and fill 'Soils. However, we anticipate it to be near the center of the existing structure. We recommend that prior to the addition of fill soils, a 3 foot removal and recompaction be accomplished below and within 10 feet of the perimeter of the structure and proposed settlement-sensitive improvements. It should be noted that deeper removals may be required and that the geotechnical consultant should observe the removal bottom prior to placement of fill soils. We also anticipate that minor grading will take place near the top of the slopes along the south and west perimeter of the site as a result of removing the existing retaining structure and constructing the new one. Therefore, we recommend that the 3 foot removal and recompaction below present grade be performed along the top of slope where the new retaining structure will be constructed. This removal shall be benched into competent material with a key at the bottom of the removal. Appendix C provides standard details for key construction. 5.3 Slope Stability Based on our professional experience in the area ~d knowledge of similar soils, it is our opinion that the proposed 2: 1 (horizontal to vertical) or flatter slopes have an adequate factor-of-safety against deep-seated stability provided the recommendations presented herein are incorporated into the design and construction of the site. It should be noted that manufactured slopes on site may be subject to rilling and erosion due to a granular nature of the onsite soils and should be land~caped as soon as possible after site grading. Overwetting should be avoided. 5.4 Foundation Desi2l1 The onsite soils were tested to have a very low expansion potential. As a result, we provide the following preliminary design recommendations for very low expansive soils. Final foundation recommendations can be provided after expansion index testing of the finish grade soils exposed at pad grade. - 8- 5.4.1 5.4.2 4971006-001 Footing Design It is anticipated that the proposed buildings will utilize a combination of continuous perimeter footings and conventional interior isolated-spread footings for building support. The following recommendations are based on the assumption that soils of very low expansion potential (50 or less per UBC 18-I-B) will be in the upper 4 feet of pad grade. This should be confirmed during grading by the geotechnical consultant and alternate recommendations provided, if necessary. Footings bearing in competent natural soil materials or properly compacted fill should extend a minimum of 18 inches below the lowest adjacent grade. At this depth, footings may be designed using an allowable soil- bearing value of 2,000 pounds per square foot (pst). The allowable soil-bearing pressure may be increased by 500 psf for each additional foot of foundation embedment to a maximum allowable-bearing pressure of 2,SÓO pounds psf. This value may be increased by one-third for loads of short duration including wind or seismic forces. Continuous perimeter footings should be reinforced by placing at least one No.5 rebar near the top and one No.5 rebar near the bottom of the footing, and in accordance with the structural engineer's requirements. We recommend a minimum width of 24 inches for isolated spread-footings. Interior column footings should be structurally isolated from the floor slab. Floor Slab Design All slabs should have a minimum thickness of 4 inches and be reinforced at slab midheight with No.3 rebars at 18 inches on center (each way) or No.4 rebars at 24 inches center (each way). Additional reinforcement and/or concrete thickness to accommodate specific loading conditions should be evaluated by the structural engineer based on a modulus of subgrade reaction of 100 kips per cubic foot. We emphasize that it is the responsibility of the contractor to ensure that tþe slab reinforcement is placed at midheight of the slab. Slabs should be underlain by a 2-inch layer of clean sand (S.E. greater than 30) to aid in concrete curing, which is underlain by a 6-mil (or heavier) moisture barrier, which is, in turn, underlain by a 2-inch layer of clean sand to act as a capillary break. All penetrations and laps in the moisture barrier should be appropriately sealed. The spacing of crack- control joints should be designed by the structural engineer. Our experience indicates that use of reinforcement in slabs and foundations will generally reduce the potential for drying and shrinkage crackiñg. However, some cracking should be expected as the concrete cures. Minor cracking is considered normal; however, it is often aggravated by a high cement ratio, high concrete temperature at the time of placement, small nominal aggregate size and rapid moisture loss due to hot, dry and/or windy weather conditions during placement and curing. Cracking due to temperature and moisture fluctuations can also be expected. The use of low slump concrete (not exceeding 4 inches at the time of placement) can reduce the potential for shrinkage cracking. Moisture barriers can retard, but not eliminate moisture vapor movement from the underlying soils up through the slab. We recommend that the floor coverings installer test the moisture vapor flux rate prior to attempting application of the flooring. "Breathable" floor coverings should be considered if the vapor flux rates are high. - 9 - 4971006-001 5.5 F outing Setback We recommend a minimum horizontal setback difference from the face of slopes for all structural footings, retaining walls, and settlement-sensitive structures. This distance is measured from the outside edge of the footing, horizontally to the slope face (or to the face of a retaining wall) and should be a minimum of H/2, where H is the slope height. The setback should not be less than 7 feet and need not be greater than 10 feet. We should note that the soils within the structural setback area possess poor lateral stability, and improvements (such as retaining walls, sidewalks, fences, pavement, underground utilities, etc.) constructed within this setback area may be subject to lateral movement and/or differential settlement. 5.6 Anticipated Settlement JfÞ The recommended allowable-bearing capacity is generally based on a maximum total and differential (elastic) settlement of I inch and 3/4 inch, respectively Approximately one-half of this settlement is anticipated to occur during construction. Actual settlement can be estimated on the basis that settlement is roughly proportional to the net contact bearing pressure. 5.7 Expansive Soils Based on laboratory testing of representative soils, the majority of the soils on site have a very low expansion potential. Expansion testing of the actual soils placed at finish grade and recommendations concerning potential expansive soils should be made after site grading has been completed. 5.8 Retainine: Wall Design Considerations Embedded structural walls should be designed for lateral earth pressures exerted on them. The magnitude of these pressures depends on the amount of deformation that the wall can yield under load. If the wall can yield enough to mobilize the full shear strength of the soil, it can be designed for "active" pressure. If the wall cannot yield under the applied load, the shear strength of the soil cannot be mobilized and the earth pressure will be higher. Such walls should be designed for "at rest" conditions. If a structure moves toward the soils, the resulting resistance developed by the soil is the "passive" resistance. For design purposes, the recommended equivalent fluid pressure for each case for walls founded above the static ground water table and backfilled with soils of very low expansion potential is provided below. - 10 - 4971006-00 I I - - on - - -~ "on --- Equivalent Fluid Wight (pcf) I Condition I Level ~ 3: 1 Slope I 2: 1 Slope I Active 35 50 55 At-Rest 55 60 65 Passive 300 300 300 (Maximum of 3 ksf) (Maximum of 3 ksf) (Maximum of 3 ksf) The above values assume tree-draining conditions. If conditions other than those assumed above are anticipated, the equivalent fluid pressure values should be provided on an individual-case basis by the geotechnical engineer. All retaining wall structures should be provided with appropriate drainage. The outlet pipe should be sloped to drain to a suitable outlet. Typical drainage design is illustrated in Appendix C: Wall back cut excavations less than 3 feet in height can be made near vertical. For back cuts greater than 3 feet in height, but less than 15 feet in height, the back cut should be flattened to a gradient of not steeper than 1: 1 (horizontal to vertical) slope inclination. For back cuts in excess of 15 feet in height, specific recommendations should be requested trom the geotechnical consultant. As previously mentioned, the walls should be backfilled with granular material. The granular material backfill should be brought up to a height of approximately 2 feet below the top of the walls and capped with compacted fill consisting of native soils. The granular and native backfill soils should be compacted to at least 90 percent relative compaction (based on ASTM Test Method D1557-91). The granular fill should extend horizontally to a minimum distance equal to one-half the wall height behind the walls. The walls should be constructed and backfilled as soon as possible after back cut excavation. Prolonged exposure of back cut slopes may result in some localized slope instability. ., Soil resistance developed against lateral structural movement can be obtained from the passive pressure values in the previous table. Further, for sliding resistance, a friction coefficient of 0.37 may be used at the concrete and soil interface. These values may be increased by one-third when considering loads of short duration including wind or seismic loads. The total resistance may be taken as the sum of the frictional and passive resistances provided the passive portion does not exceed two-thirds of the total resistance. Foundations for retaining walls in competent formational soils or properly compacted fill should be embedded at least 18 inches below lowest adjacent grade. At this depth, an allowable bearing capacity of 2,000 psf may be assumed. 5.9 Road Sign and FlagfLight Pole Design The proposed poles may be supported on cast-in-place reinforced concrete pier(s) founded in the properly compacted fill soils or Terrace Deposits at a minimum depth of 5 feet below existing grade. We recommend a minimum pier diameter of 24 inches. The pier diameter and embedment - 11 - 4971006-00 I depth may be increased due to structural requirements. The drilled pier toundation may be assumed to develop its vertical load-carrying capacity through skin &iction or end bearing or a combination of both. IF end bearing and skin &iction are utilized for load carrying capacity, we recommend that the allowable skin &iction be reduced by one-third. We recommend designing the drilled, cast-in-place, concrete pier foundation for an allowable skin friction resistance of 300 psf for downward loads and 200 psf for upward loads. We recommend that skin friction be neglected in the upper approximately I foot &om finish grade. Where end-bearing capacity is included in resisting vertical downward loads, the base of the pier excavation should be cleaned and then observed by a representative of the geotechnical consultant prior to the placement of steel and concrete. In this case, the pier may be designed for an end- bearing capacity of 3,000 psf (assuming less than 1/2 inch 6i settlement) for piers founded a minimum of 5 feet below the top of the existing grade. The above values assume a factor of safety of 2 and be inc~ed by one-third for loads of short duration such as wind or seismic loading. If UBC Section 1806 is utilized to calculate the resistance to lateral loading, an allowable lateral soil bearing pressure of 350 psf per foot of depth for properly compacted fill soils or alluvial soils. We recommend that concrete be placed in a manner that prevents segregation of the concrete mix and disturbance to the sides of the excavation. A limited shrink type of concrete is recommended to allow full mobilization of pier skin friction. We also recommend that concrete be placed as soon as possible after the pier shaft is excavated. Care should be taken to prevent caving. 5.10 Type of Cement for Construction Test results of representative at grade soils sampled during our investigation (Appendix C) indicated the soils possess a negligible soluble sulfate content. Accordingly, normal Type 1111 cement can be used for concrete in contact with onsite soils. 5.11 Pavement Design Final pavement recommendations should be provided based on R-value testing of roadway subgrade soils as [mal grades are achieved. For planning purposes, we have assumed the sandy onsite soils will have an R-value of 40. Utilizing assumed traffic indices of T.!. = 5.0, T.!. = 6.0, and T.!. = 7.0, the following structural pavement sections can be assumed for planning purposes. The project architect/civil engineer should choose the approximate traffic index. - 12 - 4971006-001 Traffic Index R-Value Structural Pavement Design Car Parking and Light R=40 3.0 inches of asphalt concrete over Auto Traffic 4 inches of Caltrans Class 2 base T.!. = 5.0 Drive Areas R=40 3.5 inches of asphaltic concrete over T.!. = 6.0 6 inches of Caltrans Class 2 base Heavy Auto and Truck R=40 4 inches of asphaltic concrete over Traffic/Fire Lanes 7 inches of Caltrans Class 2 base T.!. = 7.0 A traffic index of 4.5 is typically used for parking areas for passenger vehicles with an average daily traffic of less than 200 vehicles. A traffic index of 5.0 is similar to a cul-de-sac or local street with an average daily traffic of less than 1,200 passenger vehicles with minor truck traffic. A traffic index of 6.0 is similar to a local collector street with an average daily traffic of up to 2,500 vehicles per day with moderate small truck traffic and minor heavy (delivery-type truck traffic). The upper 12 inches of subgrade soils should be scarified, moisture conditioned and compacted to a minimum of 95 percent relative compaction based on ASTM Test Method D1557-91. If fill is required to reach subgrade design grade, fill placement should be performed in accordance with the recommendations presented in Section 5.1. The aggregate base material should be compacted to 95 percent relative compaction. For the delivery pads, drive-thru lanes, and trash coITal areas, we recommend 6 inches of Portland Cement Concrete (p.C.C.) over 4 inches of Caltrans Class 2 base. The P.C.C. in the above pavement sections should be provided with appropriate steel reinforcement and crack-control joints as designed by the project structural engineer. Minimum reinforcement should consist of 6x6-6/6 welded wire mesh at slab midheight which continues through all crack-control joints but not through expansion joints. If sawcuts are used, they should be a minimum depth of 1/4 of the slab thickness and made within 24 hours of concrete placement. We recommend that sections be as nearly square as possible. A 3,250 psi concrete mix may be utilized. Asphalt Concrete (A.C.), Portland Cement Concrete (p.C.C.) and Class 2 base materials should confonn to and be placed in accordance with the latest revision of the California Department of Transportation Standard Specifications (Caltrans) and American Concrete Institute (ACI) codes. Untreated Class 2 aggregate base should meet the most recent Caltrans specifications. We recommend that the curbs, gutters, and sidewalks be designed by the civil engineer or structural engineer. We suggest control joints, at appropriate intervals, as determined by the civil or structural engineer, be considered. If pavement areas are adjacent to landscape areas, we recommend steps be taken to prevent the subgrade soils &om becoming saturated. Concrete swales should be designed in roadway or parking areas subject to concentrated surface runoff. Regular maintenance (such as seal coats and crack infilling) is ~ important part of extending pavement life. - 13 - 4971006-001 5.12 Drainage Control Positive drainage of surface water away ITom the top of slopes toward the street, driveway or other suitable collection point is very important. No water should be allowed to pond at any location. 5.13 Graded Slopes It is recommended that all graded slopes within the development be planted with ground cover vegetation as soon as practical to protect against erosion by reducing runoff velocity. Deep-rooted vegetation should also be established to protect against surficial slumping. Oversteepening of existing slopes should be avoided during fine ~ding and construction unless supported by appropriately designed retaining structures.Y~~ - 14 - 4971006-00 I 6.& CONSTRUCTION OBSERVATION The recommendations provided in this report are based on subsurface conditions disclosed by widely spaced borings and geotechnical analysis. The interpolated subsurface conditions should be checked in the field during construction by a representative of Leighton and Associates. We recommend that all cut areas be geologically mapped for the presence of potentially adverse geologic conditions and potential ground water seepage zones by an engineering geologist from Leighton and Associates during grading. All grading operations should be observed by a representative of this firm so that construction is performed in accordance with the recommendations of this report. Grading plans and final project drawings should be reviewed by this office prior to construction. - 15 - < íá f;¡ < 0 « ¡-. z 0 II1 ;S ð ~ 8 ~ SANTA FE ~ ~ ~ ~ ~ j ~ ~ Base Map: Thomas Bros. GeoFinder for Windows, San Diego County, 1995, Page 1167 0 I 2000 4000 I Approximate Scale in Feet Proposed Taco Bell Restaurant 815 Binningham Drive Encinitas, California SITE LOCA TI 0 N MAP Project No. 4971006-001 Date 1-16-97 rnw 1042 889 Figure No.1 ~ TD~6" Approximate location of boring with total depth indicated (j}l(j)@ 6 LEGEND Y\ \ 25' I . (þ ~PACES~"I. 5+ 5 I ~ I .. I_.N I~ . j:H I :!I ..::~ 1:1' (1:1 . .", \ ~III -.1" Q.. I ._oN ~I!I . I .' ~ ;;. P I " I ':. 1:\ '\' Jw . 1/ DO RIN G LOCA TI 0 N MAP Proposed Taco Bell Restaurant 815 Binningham Drive Encinitas, California Project No. 4971006-001 Scale' 1 "=20' rnm Engr./Geol. JGF/MRS Drafted By KAM Date 1-16-96 1042 889 Figure NO.2 4971006-001 APPENDiX A REFERENCES Abbott, P.L., ed., 1985, On the Manner of Deposition of the Eocene Strata in Northern San Diego County; San Diego Association of Geologists Field Trip Guidebook, April 13, 1985. Albee, A.L., and Smith, lL., 1966; Earthquake Characteristics and Fault Activity in Southern California in Lung, R. and Proctor, R., Editors, Engineering Geologist, Special Publication, dated October 1966. Allen, C.R., Amand, P., Richter, C.F., and Nordquist, J.M., 1965, RciIationship Between Seismicity and Geologic Structure in Southern California, Seismological Society of America Bulletin, Vol. 55, No.4, pp. 753-797, 1965. Blake, 1995, EQF AUL T PC Program. Bolt, B.A., 1973, Duration of Strong Ground Motion, Proc. Fifth World Conference on Earthquake Engineering, Rome, Paper No. 292, pp. 1304-1313, June 1973. California Division of Mines and Geology, 1975, Fault Map of California, Scale 1 "=750,000'. Golden West Tacos, Inc., 1996, Site Plans entitled Taco Bell Restaurant, 815 Birmingham Drive, Encinitas, California, Sheets AlA, A1B, AIC, dated December 9. Hart, 1992, Fault-Rupture Hazard Zones in California, Alquist-Priolo Special Studies Zones Act of 1972 with Index to Special Study Zones Maps, Department of Conservation, Division of Mines and Geology, Special Publication 42, 1972. International Conference of Building Officials, 1991, Uniform Building Code. Jennings, C.W., 1975, Fault Map of California, Scale 1:750,000, California Division of Mines and Geology, Geologic Map No.1, 1975. Lamar, D.L., Merifield, P.M., and Proctor, R.J., 1973, Earthquake Recurrence Intervals on Major Faults in Southern California in Moran, D.E., Slosson, J.E., Stone, R.O., Yelverton, California, Editors, 1973, Geology, Seismicity, and Environmental Impact, Association of Engineering Geologists, Special Publication, 1973. Ploessel, M.R. and Slosson, J.E., September 1974, Repeatable High Ground Accelerations fTom Earthquakes - Important Design Criteria, California Geology, Vol. 27, No.9, 1974. Real, C.R., Toppazada, T.R., and Parke, D.L., 1978, Earthquake Epicenter Map of California, California Division of Mines and Geology, Map Sheet 39. A-I 4971006-001 REFERENCES (Continued) Schnabel, B. Seed, H.B., 1974, Accelerations in Rock for Earthquakes in the Western United States; Bulletin of the Seismological Society of America, Vol. 63, No.2, pp. 501-516, 1974. Seed, H.B., Idriss, LM., and Kiefer, F.W., 1969, Characteristics of Rock Motions During Earthquakes, Journal of Soil Mechanics and Foundations Divisions, ASCE, Vol. 95, No. SM5, Proc. Paper 6783, pp. 1199-1218, September, 1969. Singh, A. 1970, Shear Strength and Stability of Man-Made Slopes in Journal of the Soil Mechanics and foundations Divisions, ASCE, No. SM6, PP: 1879-1892. United States Department of the Interior Geologic Survey, 1968, 7.5-Minute Encinitas Quadrangle, Scale 1:24,000, Photo Revised 1975. Weber, H.F., 1982, Recent Slope Failures, Ancient Landslides, and Related Geology of the North-Central Coastal Area, San Diego County, California, California Division of Mines and Geology, Open-File Report 82-12LA. Wilson, K.L., 1972, Eocene and Related Geology of a Portion of the San Luis Rey and Encinitas Quadrangles, San Diego, California. A-2 . Date Project Drilling Co, Hole Diameter Elevation Top of Hole +/- c 0" " -of- .c of- of-., of-., C., 0.., >It- cult- ~ c..., w 0 -CUI 0.0 c..J L (.!) 0 W A A A A A A A A_A A 5 I ~{I . . . . :- .' ~~ ~ :: , , , , ,- '::::::: tv . 0 00 0" :,', ::,',:: .' . 0 '.' , ' . ." ~,/J(!, I" ¿,i'!~. "[0 o'^',~ ~ ( 0' " 15 ' r~' ~~ ,~ z::..; .;s:;. ~..:æ: ~¡:g --- --:...--~ -=ii , \ I.. -, ~~ ~1i rý" . , . . . - - 54~(11/17) III ., of- 0 Z GEOTECHNICAL BORING LOG KEY KEY TO CORING LOG GRAPHICS Sheet 1 of 1 Project ~ - 'Type of Rîg Drive Weight ft. Ref: or Datum . 0 Z ., 0. E III t/) ::n " of- of- "{) III g ,;;" L 03 U. C It- :J of- CUO of-C -L co. ell., IOCU ..., Õof- 0.. ~ E:ã c u ~te ~ ~e Drop - in, ;", III . lit/) -Ö U . =~ Logged By 0 t/) ..., Sampled By GEOTECHNICAL DESCRIPTION a. œ lnorganic day or low to medium plasticity; gtlM:Uy day¡ Andy day¡ silty clay; lean day lnorganic clay or high plasticity; (at clay OL-OH Organic day, lilt or silty day<laycy lilt mixtures ML Inorganic: lilt; very fine And; IiIty or clayey rme And; clayey lilt with low plastiåty SP 8M wen padcd And; gtlM:Uy And, little or 110 fines Poorly graded And; gtIM:Ily And, little or 110 fines Silty And; poorly graded ADd-cilt mixture Oaycy And; poorly graded ADd<lay mixture MIl Inorpnic lilt; diatomaceoul fiDe Andy or IiIty IOiIs; clastic lilt C,.ML Low plasticity day to lilt mixturc ML-SM Sandy å1t to IiIty ADd mixturc a.,.sc Sandy day to clayey ADd mixture 2- ~ SCSM Oaycy ADd to Iilty ADd mixture water ~ 81 time 04 drIq SW \ . sc OW wen graded gtIM:I; gtIM:kand mixture, little or 110 fines Poorly graded gtIM:I; gtIM:kand mixture, little or 110 fines Silty gtIM:I; p1IYCkaocki1t mixturc Oaycy gtIM:I; gtIM:kand.day mixturc " GP ON oc Saadåoac SiItstooc a.,seœc Brcc:da (aaplar ¡ravcI8Dd cobbles or matrü:"'w-ntecS ~) CoqIomerate (rouodcd ¡ravcI8Dd cobble, dut"'íI1-tccI) Ipcoaa cruJtic or cruJtic type rock MctaYoIcuJc or metamorphic rock Artffida1 or IIWHn8dc fin Asphaltic COIICICte PortIaad Cement Cœc:rcte LEIGHTON & ASSOCIATES " GEOTECHNICAL BORING LOG B-1 . bate 1-10-97 Sheet ---L- of ---L- roject Taco BelI/Birmin~Îlam Drive Project No. 4911006-001 Ibrilling Co. Ba~es Drimn~ Service Type of Rig HoHow-Stem Au2er I~ole Diameter 8 in. Drive Weight 140 pounds Drop ...M.. in. I levation Top of Hole +/- 274 fto Ref. or Datum Mean Sea Level . :J' "... tÍI" C 0 .. +- Q~ GEOTECHNICAL DESCRIPTION 0"... 0 Z 1/10 '- c..."" 1/1. ¡;:+- £:.""' .- 1/1 1/1" ::::I.. /II~ +-+- £:.01 01 01 30 C'+- u~ /1101 0.01 0.0 +- 01J... 010 "c >~ 0101 /II..J 0 - aa. 1/101 Q. -c... _en ~"" a~ c... z ICQ "" 'õ+- Logged By SCB (!) e :J' 1:5 . ~ /II a.. ._~ en c... ~"" a u Sampled By SCB 0 GW Asphalt Concrete . <> - ø 0" @ 0-2" ~-. '.-:". - - - - \ Aggregate Base ." SM @ 2"-9.5" -" 107.2 9.6 ~------------------------------------ " . 1 42 .fILL '. -" .' @ 9.5": Tan-brown, damp, medium dense, silty SAND with gravels, brick :. . . fragments 270 -: @ 2': Tan-brown, damp, medium dense, silty SAND with few rounded gravels " .. S-: .~ '. 2 39 110.2 9.2 @ S': Tan-brown with orange blebs, damp to moist. medium dense silty SAND .' -: .. ". ". -:" @ 6.5': Driller reports harder drilling -: 3 78/11" 106.4 p.3 @ 7.5': Same as at 5 feet . " ." 26S -" ' .. 10 '- ::~ 4 67 110.0 9.1 SM/SW -TËRRAëED~ÕŠITs-------------------------- -: ::~ @ 10': Tan-brown, damp, dense to medium dense, well-graded SAND -. ::~ ::~ - ' " .;.:! SM @ 13': Material becomes dark gray-brown -: '. 260 .' 15-. '. 5 3S 102.6 6.7 @ 15': Tan-brown, damp, medium dense, silty SAND with rootlet observed .' -: '. ." -. '. :' .. -' ;' .. '.' 255 -. '. " " I 20 \@ 20': Same as at 15 feet - Total Depth = 20 Peet No Ground Water Encountered at TIme of Drilling - Hole Backfilled on January 10, 1997 with Soil Cuttmgs - ~O - 25- - - - ~5 - 50 A(11/77) LEIGHTON & ASSOCIATES .. GEOTECHNICAL BORING LOG B-2 Date 1-10-97 Sheet 1 of -L Project Taco Bell/Bi["min~ham Drive Project No. 4971006-001 Drilling Co. Ba~es D["illin~ Service Type of Rig Hollow-Stem Auger Hole Diameter 8 in. Drive Weight 140 pounds Drop 2Q... in. Elevation Top of Hole +/- 274 ft. Ref. or Datum Mean Sea Level . jI " ui" c 0 .... "" QI~ GEOTECHNICAL DESCRIPTION .~" 0 Z 1/10 '- LV' 1/1' .c" .- 1/1 1/1" III~ ...."" ...."" .cO! QI ;)0 C'+- :!.... IIIQI o.QI 0.0 .... QI OLL QlO ""c -u - u. >QI QIQI III...J 0 0. -L co. .~ QI -(/) QI~ c~ L Z E COQl V' 0"" Logged By SCB (!) III a. jI I:§ ._~ W (/) L ~V' Sampled By SCB c u 0 Bag-1 GW Asphalt Concrete I> -" ~: ""-:. @D'-5' - - - - . @ 0-3" I Aggregate Base I ". SM I@ 3"4" ,~ -" ------------~------------------------ ". ..EILL -" @ 4": Tan-brown, damp to moist, medium dense, silty SAND " " 39 @ 3': Rock material encountered (cobble) 270 -" "" " @ 3': Tan-brown, moist, medium dense silty SAND 5-: ". " " 2 52 IOS.7 12.7 @ 5': Same as at 3 feet ". -" ". -: '. -: ". "" 26S -: " ." 10-: ~)(j - - - - ------------------------------------- 3 73 106.3 6.3 SW TERRACE DEPOSITS @ 10': Tan-brown damp. dense well-£l'8ded SAND - Total Depth = 11 Feet No Ground Water Encountered at TIme of Drillin~ - Hole Baclãilled on January 10, 1997 with Soil CuttIngs 260 - 15- - - - 255 - 20- - - - 250 - 25- - - - 245 - ~05A(11/77) LEIGHTON & ASSOCIATES I . -, 'Date roject Il>rilling Co. *ole Diameter I levation Top of Hole c: ~'"' £'"' I+- +- +- +- III Q/ 0. 111 > Q/ 'Q/ Q/ Q/ '+- a '+- r-V' V' ~ 270 26S 260 255 .20- ~. z45 50 A(11t77) 1-10-97 U £01 0.0 III..J c.. (!) 0 "~:'[:~I: - : '-: -:.: - ;::iii( -)nn~ -~UU) 5-:::::::: - - - - 10- - - - - 15- - - - - - - - - 25- - - - - 8 in. + 1- 274 1/'1 Q/ +- 0 Z GEOTECHNICAL BORING LOG B-3 Taco Bell/Birmingham Drive Barges Drilling Service Drive Weight ft. Ref. or Datum Sheet ----L- of----L- Project No. 4971006-001 Type of Rig Hollow-Stem Auger Drop 2!L in. . 0 Z Q/ 0. E III en J'I '"' +- of- Q/~ 1/'1 g '¡¡;,..., c.. V' 30 11.. c: '+- :::I +- Q/U +-c: on. I/'IQ/ ;ï; f¡¡ V' -õ +- a. l E§ a u 1 50/3' 103.0 2 52/6" 111.3 ,~ 140 pounds Mean Sea Level uÏ'"' 1/'1 . III en -0 u " _en ._::;; ~V' GEOTECHNICAL DESCRIPTION Logged By Sampled By SCB SCB -c;w - , Asphalt Concrete SM ~~~~--------------------------------- .HLL ' - - - - . @ 3".2': Tan orange-brown, damp, medium dense, silty SAND to well-graded SW ~--~~~------------------------------- TERRACE DEPOSITS @ 2'; Tan to orange-brown, damp, dense, well-graded SAND @ 5': Material becomes dark orange-brown, dark orange-brown, damp, dense, \ well-graded SAND Total Depth = 5 Feet 6 Inches No Ground Water Encountered at TIme of Drilling Hole Backfilled on January 10, 1997 with Soil Cuttings IF 8.5 10.2 LEIG HTON & ASSOCIATES 4971006-001 APPENDIX C Laboratory Testing Procedures and Test Results Expansion Index Tests: The expansion potential of selected materials was evaluated by the Expansion Index Test, U.B.C. Standard No. 18-2. Specimens are molded under a given compactive energy to approximately the optimum moisture content and approximately 50 percent saturation or approximately 90 percent relative compaction. The prepared I-inch thick by 4-inch diameter specimens are loaded to an equivalent 144 psf surcharge and are inundated with tap water until volumetric equilibrium is reached. The results of these tests are presented in the table below: B-2, 0' - 5' Sample Description Tan-brown, silty sand Compacted Dry Density (pet) 105.0 Expansion Index Expansion . Potential Sample Location 0 v Hvdrocollapse Tests: Hydrocollapse tests were performed on selected, relatively undisturbed ring samples. Samples were placed in a consolidometer and loaded to overburden pressure. The percent consolidation upon saturation was recorded as the ratio of the amount of vertical compression to the original I-inch height. The amount of hydrocollapse is presented below: Sample Hydrocollapse Potential Degree of Soil Location (%) Saturation (%) Material Bl @ 2' 0.17 41.0 Fill Bl @ 5' 0.01 46.4 Fill B2 @ 5' 0.02 63.3 Fill B3 @ 2' 0.04 33.0 Fill Soluble Sulfates: The soluble sulfate contents of selected samples were determined by standard geochemical methods. The test results are presented in the table below: Sulfate Potential Degree of Sample Location Sample Description Content (%) Sulfate Attack. B2, 0'-5' Tan-brown, silty sand <.005 Negligible . Based on the 1994 edition of the Uniform Building Code, Table No. 19-A-3, prepared by the International Conference of Building Officials (ICBO, 1994). C-l