HomeMy WebLinkAboutCT 72-20; LA COSTA VALE UNIT NO. 1 LOTS 11-107, 210-218, 226-231, 247-248; INTERIM GEOTECHNICAL COMPACTED FILL; 1974-02-28BENTON ENGINEERING, INC.
PHILIP HEHKING ■ENTON Pll&SIIKKf • C:IVII. &NGUutD
La Costa Land Company Costa Del Mar Road Carlsbad, Callfomia 92000
APPLlltD SOIL MF;CHANICS -FOUNDATIONS
45'71 '1 CONVOY COURT
SAN DIEGO, CALIFORNIA 9�111
�ary 28, 1974 �T&Lrl'HONII: 1714) S5S-tllllll
Sublect: Prof ect No. 72-8-18D Grading Permit No. L6392 RECEIVED
Gentlemen:
T .M. 3036 1').,1,-1-, :)0 Final Re5t on·'---"1 , c,r-.-
tompacte Fil led Grouosl V Ilk+ i..,o 1lo Costa Vale Unit No. 1 Cariibaa, Califomla
MAft 4-1974
CITY OF CARLSBAD Building Department
This is to report the results of tuts and observations made In order to inspect the compaction of filled ground placed on certain areas of La Costa Vale Unit No. 1 In Carlsbad, California. This report covers Lob 11 to 1071 Inclusive, 210 to 218, inclusive, 226 to 231, inclusive, 2tJ, and
J48. FJlled ground was placed on Lots 17 to 22, inclusive, on February lo; 1970 and t maJorgrading of the ,ubdlvislon commenced on September 21, 1972. The results of field denslty. test Nos. 1 to 1109, Inclusive, were presented in our previous reports dated March 1, 1973 and April 2, 1973. The final group of tesb token to the completion of the mafor grading on June. 7, 1973 are presented in this report. A flnal test was taken on Lot 211 on February 6, 1974.
The approximate areas and depths of filled ground placed under our inspection in accordance with the approved specifications are shown on the attached Drawing No. 1, entitled "Location of Compacted Filled Ground." The grading plan used for the placement of filled ground was prepared by Rick Engineering Company and approved August 23, 1972.
Test Nos. 1 to 1109, Inclusive, were presented in our previous reports dated March 1, 1973 and Aprtl 2, 1973. The results of the fJnal group of tests taken on the project, Nos. 1110 to 1256, inclusive, are presented on pages T-31 to T-35, inclusive, under the "Table of Test Results." The laboratory detennlnations of the maximum dry densities and optimum moisture contents of the ma)or flll materials are presented on page L-1, under the "Laboratory Test Results." Some of the maximum dry densities shown in the "Tobie of Test Results11 were combinations of thue. The tests were tcicen during the weekly periods indicated below:
Test Number
1110 to 1113, inclusive 1114 to 1124, incluslve 1125 to 1141, Inclusive
Week Ending
Morch 31, 1973 April 7, 1973 April 14, 1973
BENTON ENGINEERING, INC.
PHILIP HENKING ■ENTON
Pll&SIIKKT • C:IVII. &NGltutD
Lo Costa Land Company
Costa Del Mar Rood
Carlsbad, Callfomia 92000
APPLlltD SOIL MF;C:HANICS -FOUNDATIONS
45'71 '1 CONVOY COURT
SAN DIEGO, CALlf'O.IINIA ea111
~ary 28, 1974 ~ Tt:Ul'HON~ 1714) IS51S-IIUIIS
Sub)ect: Prof ect No. 72-8-18D
Grading Pemiit No. L6392 . RECEIVED
Gentlemen:
T. M. 3036 /).I, -i-, JO
Final Re~t on· vi ,;--
tompacte Fil led Grouosl v /U.:+ i..,o 1
lo Costa Vale Unit No. 1
Carlibaa, Califomla
MAft 4-1974
CITY OF CARLSBAD
Building Department
This is to report the results of tuts and observations made in order to inspect the compaction of
fUled ground placed on certain areas of La Costa Vole Unit No. 1 In Carlsbad, California. This
report coven Lots 11 to 1()'11 Inclusive, 210 to 218, inclusive, 226 to 231, inclusive, 2tf, and
J48. FIiied ground was placed on Lots 17 to 22, inclusive, on February lo; 1970 and t maJor
grading of the Jubdlvlslon commenced on September 21, 1972. The results of field denslty. test
Noa. 1 to 1109, inclusive, were presented in our previous reports dated March 1, 1973 and April
2, 1973. The final group of tesb token to the completion of the ma}or grading on June.7, 1973
are presented in th is report. A final teat was taken on Lot 211 on February 6, 197 4.
The approximate areas and depths of filled ground placed under our inspection in accordance
with the approved specifications are shown on the attached Drawing No. 1, entitled "Location
of Compacted Filled Ground. 11 The grading pion used for the placement of filled ground was
prepared by Rick Engineering Company and approved August 23, 1972,
Test No,. 1 to 1109, Inclusive, were presented in our previous reports dated March 1, 1973 and
April 2, 1973. The results of the fJnal group of tests taken on the project, Nos. 1110 to 1256,
inclusive, ore presented on pages T-31 to T-35, inclusive, under the "Table of Test Results,"
The laboratory detennlnations of the maximum dry densities and optimum moisture contents of
the ma}or flll materials are presented on page L-1, under the "Laboratory Test Resuhs.0 Some
of the maximum dry densities shown in the "Table of Test Results" were combinations of thue.
The tests were taken during the weekly periods indicated below:
Test Number
1110 to 1113, inclusive
1114 to 1124, incluslve
1125 to 1141, Inclusive
Week Ending
March 31, 1973
April 7, 1973
April 14, 1973
Pro)ect No. 72-8-18D
La Costa Vale Unit No. 1
-2-
Test Number
1142 to 1178, Inclusive
1179 to 1210, Inclusive
1211 to 1251, Inclusive
1252
1253 to 1255, Inclusive
1256
February 28, .197 4
Week Ending
April 21, 1973
April 28, 1973
Mat 5, 1973
May 19, 1973
June 9, 1973
February 6, 197 4
Compacted filled ground was placed on an area west of Lot 1 outside the boundca-y of La Costa
Vale Unit No. 1 and is designated on Drawtng No. 1 as Area ·11A11
•
The final results of tests and observatioN indicate that the compacted filled ground has been
placed at 90 percent of the maximum dry density or greater. It has been detennined that the
flll matertals, compacted to 90 percent of the maximum dry deNlty, have a safe bearing value
of 1650 pounds per squcre foot for one foot wide continuous footings founded at a depth of one
foof below the lowest odfacent compacted ground surface. This value may be Increased to 1950
pounds per square foot for 16 inch wide footings placed 1.5 feet below·th4! lowest adJacent com-
pacted ground surface. If footings are placed closer to the exposed slopes than 5 feet inside the
top of compacted filled ground slopes, these should be deepened one foot below a 1 1/2 horizontal
to 1 vertical line protected outward and downward from a point 5 feet horizontally inside the top
of compacted filled ground slopes. Tests indicate that the compacted filled ground is adequate
to satisfactorily support the proposed one md two story wood frane dwellings without detrimental
settlements.
Only nonexpanslve soils were placed in the upper three feet below finished grade on the following
lots:
/ 1 to 10, inclusive
/100 to 209, inclusive :,HOM EXPlt.NSIV~
. 219 to 225, inclusive ARt=
232 to 246, inclusive ~X P/tN~lllir
. . 1)'/'&•~ I I
All expansive solls existing in the upper three feet below finished grade in cut areas ancl areas of
shallow ftll were removed on the above lots end were replaced with properly compacted non-
expansive fill soils. Therefore, special design for expansive soil conditions will not be required
on these lots.
... ---------. ., 1V ot~pr )~ffi a.n the subdivlslon were determined to have crHicall e lve soils n the upper teeeer f ow finished grade. Therefore, tn order to m n1m1ze poss1 e etnmental effects
caused by these potentially expansive sotls, the fol lowfng special design ond preca~tfom are
recommended.
1. Avoid the use of fsolated interior piers where possible. Use continuous
footings throughout, and place these at a minimum depth of two feet below
the lowest adlacent exterior final grou;id surface.
Project No. 72-8-180 -3-February 28, 197 4
La Costa Vale Unit No. 1
2, Reinforce and interconnect continuously with steel bars all interior and
exterior footings with one #5 bar at 3 inc:hes above the bottom of all
footings with one 15 bar placed 1 1/2 inches below the top of the stems
of the footings,
3, Railed wooden floors that span between continuous footings are preferable.
Concrete slabs on grade should be reinforced with at least 6 x 6 -10/10
welded wire fabric. Provide a minimum of 4 inches of crushed rock 3/4
to 1 inch In size beneath all concrete slabs. A moisture barrier should
also be provided over the crushed rock and then 2 inches of sand should be
placed over the moisture barrier and below the bottom of the slab.
4. Separate garage slabs from perimeter footings by 1/2 inch thickness of
construc:tton felt or equivalent, to ,dlow Independent movement of garage
slabs relative to perimeter footings. Assure complete separation by extending
the construction felt over the full depth of the front thickened edge of the
garage slab. Cut off gcroge door stops at least 1/2 inch above the garage
slob.
5. Provide positive drainage away from all perimeter footings with a vertical
fall of at least 6 inches in a horizontal distance of 5 feet, to a distance of
at least 5 feet outside the house walls.
6. Exercise every effort to assure that the soil under the concrete slabs has a
uniform moisture content at least 1 to 3 percent greater than optimum
throughout the top 1 .5 feet below finished grade at the time of placing the
foundations and slabs.
Respectfully submitted,
BENTON ENGINEERING, INC.
By.£~~
R. C. Remer
RCR/PHB/pk
Distr: (4) Addressee
( 1) Addressee, Attention: Mr. Burton L. Kramer
San Diego County F.ngineering Department
(1) Attention: Mr. H. M. Taylor
(1) Attention: Mr. Willard Robinson, Room 206
(2) City of Carlsbad Building Department
(1) Rick Engineering Company, Carlsbad
(2) Tttle Insurance and Trust Company _A.,_._ __ a.t .. _ ft . al I ft I
I June 29, 197J Project No. 72-8-1 lD T-31
la Costa Vale Unit No. 1 Revised February 28, 1974
TABLE OF TEST RESULTS (CONT.)
Approx-Depth Maximum
.; .... lmate of FIii Field Dry Dry
·_._.Test Location at. Test Moisture Density Density Percent
_,.. .. No Lot N In Feet .% dry wt' lb/cu ft lb/cu ft Compaction Remarl<s :-eL... . .• . o. ,;~A-.,:.i .. f?1Y10 · ·-16 54.0 15.5 111.0 118.8 93.4
· t \1'1°11 15 48.0 15.9 114.4 118.B 96.3
~(,-!•• . : 17 51_.0 16.5 113.7 118.8 95.7 .:. __ ._ -1112 .
·;, °1"113 17 53.0 17.2 108.8 115.2 94.4
1114 11 59.0 * 15.1 105.2 116.3 90.4
1115 12 56.0 * 21.8 104.9 115.2 91.0
.. 1116 _13 51.5 * 16.5 108.9 116.3 93 •. 5
1117 30 4.0 * 13.1 113.1 118.8 95.2 -..
1118 18 41.0 20.2 108.1 118.8 91.0
. 1119 14 53.0 * 15.2 114.0 118.8 95.9
1120 20 29.0 15.4 110.1 118.8 92.7
1121 21 20.0 18.6 113.8 118.8 95.8
1122 19. 32.0 16.6 111.6 118.8 93.8
1123 54 2.0 17.3 108.0 111.2 97.2
1124 55 6.0 19.6 100.2 111 .2 90.2
1125 56 .1.0 12.5 109.0 116.3 93.7
. 1126 22 14.0 13.1 . 110.0 116.3 94.5
.1127 Romerta St. 3.0 10.3 114.5 118.8 96.5
Opp. Lot21
1128 RomertaSt. .5.0 12.5 110.1 118.8 92.6
Opp. Lot22
1129 RomertaSt. 7.0 • 14.8 110.6 116.3 95.1
Opp. Lot21
1130 29 1.0 13.5 114.5 118.8 96.5
1131 30 1.0 15.6 107.9 116.3 92.7
1132 29 3.0 14.9 111.4 118.8 93.7
1133 30 3.0 * 13.7 116.1 118.8 97.7
1134 28 1.0 14.0 107.8 116.3 92.6
1135 26 2.0 14.5 111.8 J 16v3 96.1
1136 39 4.0 18.5 103.8 115.2 90.0
1l37 40 6.0 14.6 106.3 116.3 91.6
1138 41 2.0 17.0 103.7 115.2 90.0
1139 42 2.0 10.0 109.5 118.8 92.1
1140 39 6.0 16.5 105.6 116.3 90.7
1141 40 a.a 11.6 111.0 116.3 95.4
1142 31 2.0 12.3 113.9 118.8 ·. 95.9
1143 25 2.0 16.7 105.4 116.3 90.7
1144 LaCosta Ave. 2.0 16.4 113.8 120.8 94.2
Opp. lot 31
• lncUcates Finished Grade
Preject No. 72-8-180 T-32 June 29, 197J
la Costa Vale No. 1 Revised February 28, 1974
TABLE OF TEST RESUL'JS (C:ONT.)
Appn>x• Depth Maximum
imate of Fill Field Dry Dry
Test Location at Test Moisture Density Density Percent
No. Lot No. In Feet. % dry wt lb/cu ft lb/cu ft Compaction Remarks
1145 LaCostaAve. 2.0. U.2 116.0 118.8 97.6
.... Opp. Lot37
.>J}46 -· -La Costa Ave. ~-.o 12.7 112.0 : ·. 118.8 94.1
Opp. Lot41
.1147 LaCostaAve. 2.0 11 .8 110.8 116.3 95.2 Stormdrain
Opp. Lot39 Backflll
1148 22 16.0 12.6 119.0 128.0 93.0
1149 58 2.0 17.1 112.7 123.6 91.2
.1150 59 1.0• 12.6 111.0 116.3 95.4
1151 21 22.0 18.7 108.7 116.3 93.4
1152 20 31.0 16.2 112.7 116.3 96.9
1153 19 34.0 22.0 106.6 116.3 91.6
1154 18 41.0 15.9 114.3 116.3 98.3
1155 Azahar St. 9.0 15.7 112.4 116.3 96.6
&Romeria St.
1156 Azahar St. 11.0 13.0 119.3 123.6 96.6
& Romerta St.
1157 Cadencia St. 13.0 24.1 103.1 113.7 90.7
& Romerta St.
1158 Cadencta St. 15.0 20.8 106.7 113.7 93.8
& Romeria St.
1159 Garboso St .. 29.0 14.9 105.3 110.4 95.3
& Romeria St.
1160 RomeriaSt. 25.0 15.5 117.7 128.0 92.0
Opp. Lot7&8
1161 21 24.0 * 11.9 117.6 128.0 91.8
1162 20 . 33.0 * 17.4 111.3 116.3 95.7
1163 .
19 36.0 • 16.9 110.1 116.3 94.7
1164 18 43.0 * 17.2 113.4 123.6 91.7
1165 17 55.0 * 15.4 104.8 116.3 90.1
1166 16 56.5 * 18.5 106.3 116.3 91.4
1167 15 50~0 * 18.0 104.6 115.2 90.6
1168 29 3.0 • 13.3 117.4 123.6 95.0
1169 28 3.0 * 9.8 113.8 116.3 97.8
1170 Cadenc ia St. 1.0 9. 1 117.3 118.3 98.7
Opp. lot99
1171 CadenciaSt. 1.0 19.2 104.0 111.2 93.5
Opp. Lot 102
Project No. 72-8-180 T-33 June 29, 1973
La Costa Vale No. 1 Revised February 28, 1974
TABLE OF lcST RESULTS (CONT,)
Approx-Depth Maximum
lmate of FIii Field Dry Dry
Test Location at Test Moisture Density Density Percent
No. Lot No. in Feet % dry wt lb/cu ft lb/cu ft Compaction Remarks
1172 CadenciaSt. 1.0 19.6 111.7 112.7 99.0
Opp. Lot 105
1173 CadonclaSt. 2.5 * 12.0 107.8 116.3 92.7
Opp. Lot 100
1174 CadenctaSt. 2.5 * 13.4 104.1 111.2 93.6
Opp. Lot 103
1175 CadenclaSt. 2.5 * 17.8 101.4 111.2 91.2
Opp. Lot 105
1176 27 2.0 12.6 117.3 123.6 94.9
1177 26 4.0 * 14.6 115.0 123.6 93.1
1178 22 18.0 * 12.2 117.6 123.6 9S.1
1179 24 2.0 12.0 110.7 116.3 95.1
1180 2S 4.0 * 13.9 110.4 116.3 95.0
1181 101 4.0 20.4 104.4 115.2 90.6
1182 71 19.0 * 15.4 112.2 118.8 94.5
1183 102 18.0 * 18.5 102.0 111.2 91.7
1184 70 11.5 * 16.2 112.7 118.8 95.0
1185 24 4.0 • 13.7 ·]09.9 116.3 94.5
1186 230 35.0 * 17.9 113.0 118.8 95.0
1187 230 35.0 * 22.8 105.0 116.3 90.3
1188 229 40.0 • 20.1 107.4 116.3 92.2
1189 229 40.0 * 19.7 107.0 118.8 90,0
1.190 101 6.0 * 20.4 104.2 115.2 90.4
1191 103 19.0 * 19. 1 109.3 116.3 94.0
1192 105 12.0 • 21.2 103.8 115.2 90.0
1193 106 8.0 * 18.0 107.6 115.2 93.4
1194 107 7.0 * 22.3 102.2 113.2 90.2
1195 76 7.5 • 20.2 107.9 118.8 90.7 . 1196 75 19.0 • 19.7 106.2 116.3 91.3 -
1197 74 21.0 • 18.9 104.3 115.2 90.5
1198 73 21.0 • 14.6 108.7 115.2 94.4
1199 72 14.0 * 16.4 108.2 116.3 93.0
1200 228 33.0 • 19.6 107.0 116.3 92.0
1201 228 33.0 • 23.2 105.5 115.2 91.6
1202 227 31.5 * 23.8 102.6 113.2 90.6
1203 227 31.5 * 17.5 107.1 118.8 90.2
1204 226 22.0 * 12.8 104.5 111.2 93.9
1205 83 21.0 17.2 105.7 115.2 91. 7
Project No. 72-8..:100 . T-34 June 29, 1973
Lo Costa Vale No. 1 Revised February 28, 1974
TABl.e OF TEST RESULTS (CONT.)
Approx-Depth MCl)(tmum
tmate of Ftll Field Dry Dry
Test Location at Test Moisture Density Density Percent
No. Lot.No. In Feet % dry wt lb/cu ft lb/cu ft Compaction Remarks
1206 83 24.0 * 13.1 114.O 118.B 96.0
1207 84 39.0 • 10.B 115.5 118.8 97.2
1208 58 3.0. 13.1 104.3 115.2 90.5
1209 31 4.5 * 11.B 109.1 116.3 93.8
1210 39 8.0 * 13.7 104.6 116.3 90.0
1211 ,4() 11 .. 0 • JJ.4 113.O 118.B 95.2
1212 55 8.0 20.4 101.a 111.2 91.6
1213 55 . 10.5 • 17.8 100.9 111.2 90.6
1214 218 4.0 16.3 110.0 116.3 94.7
1215 217 4.0 21.0 104.0 115.2 90.3
1216 218 6.0 17.7 104.5 115.2 90.7
1217 216 8.0 20.4 114.2 118.8 96.1
1218 218 8.0 18.7 102.8 113.2 90.7
1219 215 6.0 17.8 108~6 118.8 91.4
1220 215 .s.o 18.0 11).4 118.8 93.8
1221 216 10.0 19.1 105.8 116.3 90.9
1222 215 12.0 20.6 107.8 116.3 92. 7
1223 216 12.0 16.1 107.6 116.3 92.5
1224 211 6.0 . 21.2 106.7 116.3 91.7
1225 212 8.0 20.6 109.2 118 .. 8 92.0
1226 218 10.0 • 12.6 107.1 116.3 92. 1
1227 217 6.0 • 14.8 114.1 118.B 96.0
1228 216 u.s. )3.6 112.7 118.B 94.B
·1229 215 14.5 • 14.3 107.0 116.3 92.1
1230 214 6.0 • 23.4 102.8 113.2 90.7 ·
1231 . 212 J l .O • 18.0 105.0 116.3 90.2
1232 41 10.0 • 12.6 112.0 118.8 94.l
1233 32 2.0 • J0.6 115.5 118.8 97.2
1234 33 2.0 * 11.8 121.6 128.0 95.0
1235 34 2.0 • 12.4 117.8 118.8 92.0
1236 35 2.0 • 11.5 109.0 116.3 93.6
1237. 36 ·2.0 • 10.0 120.0 128.0 93.9
1238 37 2.0 * 9.8 112.0 116.3 96.3 -
1239 38 2.0 • 12.9 106.6 116.3 91.7
1240 104 16.S * 19.2 104.0 115.2 90.3
1241 54 4.5 • 10.0 114.5 116.3 98.4
1242 56 3.0 * 11.5 113.0 118.8 95.1
1243 48 0.0 • 15.5 109.0 . 118.8 91.8
1244 47 18.0 * 19.0 107.5 116.3 92.4
1245 46 19.0 * 19.8 107.2 118.8 90.2
1246 45 16.0 * 12.6 115.4 118.8 97.1
1247 # 1 J.O • 11.6 113.7 118.8 96.4 ·
1248 43 5.0 • 9.5 112.5 118.8 94.6
1249 42 6.0 • 12.7 120.0 128.0 93.5
BENTON ENGINEERING. INC.
Project No. 72-8-18D T-35 February 28, 1974
La Costa Vale No. 1
TABLE OF TEST RESULTS (CONT.)
Approx-Depth Maximum
imote of FIii Field Dry Dry
Test Location at Test /v't:Jisture Density Density Percent
No. Lot No. In Feet % dry wt lb/cu ft lb/cu ft Compaction Remarks
1250 27 4.0 * 11.0 111.9 118.b 94.2
1251 57 2.0 * 15 .. 6 114.0 118.8 96.0
1252 211 9.0 * 15.2 87.0 111.2 78.2 Reworked
1253 Electrical Box 2.0 10.1 109.0 120.6 90.4
Front Lot 222
1254 Electrical Box 4.0 12.4 118.1 123.6 95.6
Front Lot 222
1255 Electrical Box 6.0 • 11.3 118.2 123.6 95.7
Front Lot 222
1256 211 9.0 * 16.0 113.2 123.6 91.7 Check on 1125:
* Indicates Finished Grade
BENTON ENGINEERING, INC.
Project No. n-8-18D
La Costa Vale Unit No. 1
L-1 Morch l , 1973
Revised -April 2, 1973
Revised February 28, 1974
LABORATORY TEST RESULTS
The maximum dry densities and optimum moisture contents of the maJor flll materlals as determined
by the A.S.T .M. D 1557-66T method, that uses 25 blows of a 10 pound rammer falling from a
height of 18 inches on each of 5 layers in a 4 Jnch diameter l/30 cubic foot compaction cylinder,
are presented as fol lows:
Soil Description
Light brown gray clayey silt
Ollve green silty clay ·
Brown gray silty clay
Light yeJlow brown sJlty very fine to fine sand with
clay binder and chunks of silty clay
Yellow brown and gray very fine sandy silt
Yellow brown very fine to fine sandy clay
Gray brown fine sandy clay
Olive green silty clay ·
Light brown silty fine sand
.1 Light gray yellow clayey fine sand
Light gray brown clayey very fine to fine sand
Groy with red brown and whHe silty clay
Light gray brown clayey fine sand
· Light gray silty very fine to fine sand with slight
clay binder ·
Gray black silty clay
Brown clayey fine sand with some fine sandy clay
Light brown silty fine sand with clay binder
Light brown and gray silty clay
li9ht yellow brown fine scndy clay
Light yellow silty fine sand
Greenish brown fine sandy clay
Brown clayey fine to medium sand
Grayish brown silty fine sahd
Light brown silty fine to medium sand
Red brown fine to medium sandy clay
Light gray clayey silt with streaks of red brown
and yellow ·
Light 91"Q)' silty clay,with yellow streaks
Light gray silty fine sand
UIENTON ENGIN~ERING, INC.
Maximum Optimum Mois-
Dry Density ture Content
lb/cu ft % dry wt
107.2 19.0
107.5 16.4
100.0 17 .. 8
109.2 16.8
110.4 15.4
110.4 15.5
J 10.9 · 14.3
111.2 15.0
112.5 10.9
114.1 13.9
114.2 14.4
114.7 15.3
115.2 14.7
115.2 13.7
116.8 11.8
117 .8 13.3
118.3 11.9
118.6 14.0
121.6 11.5
123.6 10.5
118.8 12.2
128.0 9.2
117.0 13 .1
118.5 12.0
111.3 15.0
111.3 16.0
110.7 15.1
111.8 12~5
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HETHERINGTON ENGINE,E,R:ING, INC.
SOIL & FOUNDATION ENGINEERING • ENGINEER1NG GEOLOGY • HYDROGEOLOGY
MLC Homes, Inc.
1500West111h Avenue, Suite 24
Escondido, California 92029
Attention: Mr. Gltn Carson
Subject; GEOTECHNICAL FEASIBIL.ITY S11JDY
Proposed Single-Family Residences
Romeria Street
La Costa Vale -Unit No. 1, Lots 20 through 22
Carlsbad, Califorrua
References: Attached
Dear Mr. Carson:
October 26, 2015
ProjectNo. 7802.1
Log No, 17971
In accorda.oce with your request, we have performed a geotechnical feasibility study of the
subject property. Our work was petformed during October 2015. It is our understanding that
proposed construction consists of three single..fiunily residences. We have not been provided
with plans at this time. The purpose of our work was to evaluate general geologic and soil
conditions at the site to determine the suitability of the lots for the proposed sing]e-famiJy
residences.
With the above in mind, our scope of services included the following:
• Research and review of available geotechnical reports and geologic maps/literature
pe11inent to the site and immediate vicinity (see References).
• A site reconnaissance oftbe property.
• Engineering and geologic ana1ys~8.
• Preparation of this rep01t presenting our findings, conclusions and recommendations.
SITE DESCRIPTION
The subject property is located at the southwest comer of La Costa Avenue and Romeria
Street in Carlsbad~ California (see Location Map, Figure 1 ). The site is further identified as
La Costa Vale -Unit No . 1, Low. 20 through 22. The .site co1,s.ists of three contiguous
rectangular shaped residential lots. Jbe lots are vacant of improvements and support a low
growth of scattered weeds, grasses, and several trees,
5365 Avenlda Encinas, Suite A • Carlsbad, CA 92008-4369 • (760) 93H 917 • fax (760) 931--0545
327 Third Street• Laguna Beach, CA 92651-2306 • (949} 715-5440 • Fax (949) 715-5442
www hP.lhP.rinnlominninP.P.rinn.r.om
ADAPTED FROM: The Thom,is Guide, San Diego Count,, 57th �- Page·1147
SCAL.E: 1N - 2000'(1 Grid Equals: 0.5 :x .0.5 miles)
LOCATION MAP
HETHERINGTON ENGINEERING, INC.
GEOTECHNICAL CONSULTANTS
Romeria Street!MLC Homes/Lots 20-22 Carlsbad, California
PROJECT NO. 7802.1 I FIGURE NO. 1
GEOTECHNICAL FEASIBILITY STUDY
Project No. 7802 . .1
Log No. 17971
October 26, 2015
Page2
Topographically, the lots consist of three level buiJdhlg pads, separated by 6 to 9~feet high
1.5: 1 ·(horizontal to vertical) slopes. A descending slope at the rear of ·the lots varies from l 0
to 15-feet high at a 2:1 {horizontal to vertical) slppe r~tio. The site is bounded by Rome1ia
Street on the east, La Costa Avenue on the north, an existing single-family residence on the
south, and undeveloped property on the west.
PROPOSED DEVELOPMENT
We understand that three singJe-farnily residences are proposed for the lots. It is anticipated
that the residences will be at about existing pad grades.
PUBLISHED DOCUMENTS/RESEARCH
Research at the c-ity of Carlsbad resulted in finding the referenced ~oil reports and grading
plans (References 1 through 3). These documents indicate the subject three lots are underlain
entirely by compacted fill pfaced incrementally during rough grading between 1970 and
1973. Based on the ayailab-Je, data~ fill u-p to 30±-feet thick was reportedly placed near the
rear of the building pads with 5-feet or less of fill placed adjacent to Romeria Street. Soils
with a high to very high expansion potential reportedly unde.rlie tbe lots.
A publ~hed geologic map (Reference 4) indicates the documented fi11 is likely underlain by
Santiago Formation bedrock. Geologic literature indicates that !.IO ~ctive or poteutia.Hy active
faults or landslides have been mapped or are known t.o exist within the subject property and
the site does not He within the presently defined Hmits of an Alquist .. Pr.iolo Earthquake Fau!t
Zone.
FINDJNGS
Based on the results of our geotechnical feasibility study, the proposed residences are
considered feasible from a geotechnical standpoint. There are no obvious, reported, or known
geologic haz.ards within the property that would preclude development of the site from a
geologic standpoint.
Conditions considered favorable for development of the property 1nclude a) documentedfill,
b) no ~vidence of faulting 01· landsliding within the subject site or reported in published
documents, and c) no known or reported .shallow grom1dwater conditioos, Geotechnical
conditions whfoh sboµld be considered dudng the pJannh:ig for site development include: :a)
highly to very .highly expansive soils, b) 1.5:l {horizontaJ to v.ettical) fill slopes that
reportedly exist between the building pads, and c) the effect of ground shaking generated
from potential eatthquakes on one of the major fault zones in the region.
HETHERINGTON ENGINEERING, l'NC.
GEOTECHNICAL FEASIBILITY STUDY
Project No. 7802.1
Log No. 17971
October 26, 2015
Page3
A geotechnica.l investigation (including subsurface exploration, laboratory testing, and
engineering/geo.logjc analysis) is I'.Ccommended to confirm the subsurface conditions.
evaluate the existing documented fill, and provide relevant geotecbnical conclusions and
recommendations for site grading and construction. A proposal for a geotechnical
investigation can be provided upon request
This opportunity to be of service is sincerely appreciated. If you have any questions
regarding this report, please contact this office.
Sincerely,
HETHERINGTON ENGINEERING, INC.
Ike--
Professional Geologist
Certified Engineering G
Certified Hydrogeolo •
(expires 3/31/16) ·
Attachments; Location Map Figure l
Geotechnical E
(expires 3/31/1
Distribution; I-via e-mail (Kevin1500west@aol.com)
HETHERINGTON ENGINEERING, INC.
TOPOGRAPHIC SURVEY
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