HomeMy WebLinkAbout; Stagecoach Park; Stagecoach Park; 1986-05-07STAGECOACH PARK
EARTHWORK REVIEW <fe ESTIMATE
of
REMEDIAL QUANTITIES
Prepared for:
H <fc A CONSTRUCTION COMPANY CORP.
11345 Post Hill Road
Lakeside, California 92040
Prepared by:
Rancho Bernardo Engineering
Rollie H. Magboo
17877 Creciente Way
San Diego, California 92127
May, 1986
TABLE OF CONTENTS
I. Introduction
II. Summary o-f Grading Quantities
Table I
III. Volume Calculations
Buttress Control Area
Terrace Deposit Area
Bedrock Creep Area
Alluvium
Topsoil
IV. Appendix
Seocon's Field Report, dated Oct. 28, 1985
City o-f Carlsbad's letter dated Oct.30, 1985
Alluvium and Topsoil Thicknesses - page 5 of
Soils Report, dated July, 1985
Buttress Key Cross-Sections per Appendix B o-f
Soils Report, dated July, 1985
Compaction Test Nos. 16, 38, 61, and 118 from
Table II Summary o-f Field Density Test
Results, by Geocon, dated December, 1985
Exhibit 1 Remedial Grading
corresponds to Sheet 2 o-f Grading Plans
Exhibit 2 Remedial Grading
corresponds to Sheet 3 of Grading Plans
Exhibit 3 Remedial Grading
corresponds to Sheet 4 of Grading Plans
Exhibit 4 Locations of Compaction Tests
I. INTRODUCTION
I. INTRODUCTION
A. Location
Stagecoach Park is a 29 acre parcel located along Mision
Estancia, approximately 700 -feet east of its intersection
with Rancho Santa Fe Road, in Rancho La Costa.
B. Purpose
H & A Construction Company Corp. was awarded the contract
to do the grading on this project. The contractor completed
the work around the middle of February, 1986. The contractor
claims that he exceeded the scope o-f work as called out in
the contract and has retained Rancho Bernardo Engineering to
calculate the amount o-f overexcavation based on -field
measurements.
C. Background Information — Grading Contract Items
The contract identifies four items of work related to grading,
1. Item No. 1 refers to the standard grading and the City's
estimate for this item of work is 160,OOO C.Y. The
contractor agrees with this amount.
2. Item No. 2. refers to the "excavation, stockpiling and
compaction of organic and alluvial soils identified by
the soils engineer on-site." The City has estimated
10,OOO C.Y. for this item. The contractor's engineer
differs with this amount and estimates 60,400 C.Y. for
this item.
3. Item No. 3 refers to the "remedial grading and excavation
as per soils engineering report." The City has estimated
8,000 C.Y. for this item. The contractor's engineer
differs with this amount and estimates 129,8OO C.Y. for
this item.
4. Item No. 3A. "Unclassified excavations"
As interpreted by the contractor, any overexcavation
beyond the scope of work would be compensated in
accordance with this item of the contract.
D. Bidding Grading Projects — Standard Practice
From the information obtained by the review of the grading
plans, contract documents and discussions with the
contractor, the following items were not included in the bid
packages sent to the contractors who bidded on this project.
The grading quantities, i.e. the bulk cut and fill amounts,
are normally shown on the grading plans. In this case, they
are not, but are called out in the contract as Item No. 1.
As mentioned earlier, the contractor agreed with the estima-
ted quantity of 160,000 C.Y.
It is also standard practice, or is the norm in grading
projects with substantial remedial quantities, that a "soils
package" is prepared by the soils engineer. This soils
package would show the limits o-f the remedial grading and
the estimated quantities for each area on the grading plans.
This soils package is then included in the bid documents sent
to the contractor. With this i n-f ormation, the contractor has
a clear understanding as to the kinds and amounts o-f remedial
grading he has to do. Furthermore, additional compensation to
the contractor or credit to the agency will be relatively easy
to monitor due to actual load counts in the field relative to
the contract amounts.
It is recommended that a soils package be prepared and
included in the bid documents on future city grading projects
wherein there are substantial remedial grading.
E. References and Supportive Data
The following references were used in the preparation of this
report:
1. The soils report "Geotechnical Investigation for
Stagecoach Park" by Beacon, Incorporated, July,1985.
a. Alluvium — areas are clearly delineated and the depths
of removals are given.
- 5—foot removals along canyon areas
- 20—foot removals along the main drainage area (Note:
from page 5 par 1 - "It is our understanding that
this main drainage area is not proposed for
development."
On sheet 2 of the grading plans two relatively small
rectangular areas are called out for 5—foot removals:
please see section on alluvium under volume
calculations for detailed discussion.
b. Topsoil — per page 5, "the average thickness is
between one foot and two feet." An average of 1.5
feet thickness is used in the calculations.
c. Buttresses - The dimensions shown on the buttress key
cross—sections in Appendix B of the soils report were
used.
d. Colluvium - For the areas that were excavated upon the
direction of the soils engineer, the net volume after
subtracting the 1.5 feet of topsail and alluvium
material is assumed to be colluvium material.
2. Compaction testing report "Final Report and Observation
Services Daring Grading Operations -for Stagecoach Park" by
Geocon, Incorporated, December, 1985. The depths of
removals as noted by the grading foreman on his field set
of grading plans were substantiated by the soils
engineer's compaction test data.
3. Surveyor's cut sheets by CEPA Surveys, Inc. The cut
sheets show the surveyed limits of the buttress control
area and the bedrock creep area. The elevations of the
original ground are also noted. The grading foreman then
measured and noted the depths of cut on his field set of
plans.
4. The grading foreman's field set of grading plans.
F. Soils Engineer's Direction of Scope of Remedial Grading
From the review of Geocon's field reports, it is clearly
evident that the soils engineer did provide the direction as
to the extent of remedial grading. Please see Geocon's Field
Report dated 10-28-85 in the Appendix.
G. Chain of Command
Please the City's letter, dated October 30, 1985, reconfirming
Mr. Norm Scott as special inspector "in—charge of the grading
operations at the park site. All problems and issues
regarding the park grading will be brought to Norm's attention
first." A copy of this letter is in the Appendix.
II. SUMMARY OF GRADING QUANTITIES
TABLE I,STAGECOACH PARK
SUMMARY of GRADING QUANTITIES-
•for ITEMS 2 & 3 of CONTRACT-
C.Y. (Cubic Yards)
Description of
Contract Item
2. Excavation, stockpil-
ing, placement and
compaction of organic
and alluvial soils
identified by Soils
Engineer
3. Remedial grading and
excavation as per
soils engineering
report
TOTAL
Per
Contract
10,000*
18,000 C.Y.
Per
Soils Report
•
27,500«=
30,400=
57,900
Actual
Removals
6O , 4QOcl
129,800*
190,200
NOTES: a. Quantities rounded off to nearest hundred
b. City's consultant's estimates on entire project
c. Contractor's engineer's estimates. The topsoil portion
is based on areas calculated only and not for the entire
project. The alluvium portion is based on specific
recommendations in the soils report and as shown on the
grading plans.
Topsoi1
Alluvium
19,835 C.Y.
7.643
27,478 C.Y.27,500 C.Y.
Contractor's engineer's estimates. The topsoil portion
is based on areas calculated only and not for the entire
project. The alluvium and colluvium portions are based
on field measurements as shown on the grading foreman's
marked—up field set of grading plans.
Topsoi1
Alluvium
Colluvium
19,835 C.Y.
26,447
14.132
60,414 C.Y.6O,40O C.Y.
Quantities shown are over and above the 16O,OOO C.Y.
of standard grading, Item No. 1 of Contract.
III. VOLUME CALCULATIONS
BUTTRESS CONTROL AREA
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IV. APPENDIX
•• \GEOCON
INCORPORATED«
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V*' v«^' REPORT NO V-
FIELD REPORT MTr(,, {Q/l?As
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-YPF OF COMPACTOR ,._ ........
REMARK 9
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OURS CHARGED
INTRACTOR HOURS
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1200 ELM AVENUE • ]$&' • TELEPHONE
CARLSBAD, CA 92008-1989 •^Wr^M ' (619)438-5541
Office of the City Engineer
Op of Cartetrab
October 30, 1985
H & A CONSTRUCTION COMPANY
Fred Howe, Const. Superintentendent
11345 Posthill Road
Lakeside, CA 92040
As of October 29, 1985, The City's Project Manager for
Stagecoach Park will be 3im McLean (telephone 438-5540).
The Special Inspector, Norm Scott will remain in charge of
grading operations at the park site. All problems and
issues regarding the park grading will be brought to
Norm' s attetion first.
RICHARD H. ALLEN, JR.
Municipal Projects Division Manag-er
RHA:mg •
File No. D-3A.80-J01
July 5, 1985
accumulated near the base of slopes or along canyon bottoms. The maximum
observed thickness in the areas to be developed was found to be on the
order of 5 feet. It is anticipated that the .alluvial soils in the main
drainage area would have thicknesses in excess of 15 to 20 feet. It is our
Development within areas •containing alluvial or colluvial deposits will
require remedial grading in the form of removal and recompaction to
mitigate potential settlement problems.
The majority of the site was found to be covered by stiff to
very stiff, "gray, s.andy <ilay topsails. '
Due to the loose, unconsolldated condition of the topsoils as well as their
expansive potent±al,0JSt^£f&^£ES&88^3St&*f* such as recompaction,
deeper than normal sideslope fill keys and undercutting of transition pads,
-•X
will be necessary.
Groundwater
Groundwater was not encountered in any of the test excavations at the time
of the field investigation. It is anticipated that groundwater is present
in the main drainage channel in the northern portion of the property. A
small pond is present in the main drainage area near Mission Estancia.
-5-
GEOCON
File No. D-3480-J01
September 20, 1985
,J
FINISH GRADE
NOTES: •
1. Base of shear key to be 2 feet minimum below slide plane and 40 feet
minimum in width.
2. Shear key material to be properly compacted granular material.
3. Backslope and front slope to be 1.0 to 1.0 or flatter.
4. If subdrain required drain shall be 4-inch minimum perforated ABS or
PVC pipe .sloped to drain to convenient outlet. Pipe to be surrounded
by Class II permeable material (CalTrans Specifications Section
68-1.025) extending at least 5 feet above slide plane or seep,
whichever is higher.
STAGECOACH PARK
CARLSBAD, CALIFORNIA
Figure 1
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