REVIEWED BLD2023-1063+Geotech Design Report+8.30.2023_10.58.18_AM+3755508REViEWE� RECEIVED
BY Sep 19 2023
CITY OF EDMONDS CITY OF EDMONDS
DEVELOPMENT SERVICES
e BUILDING DEPARTMENT, DEPARTMENT
BLD2023-1063
GEOTECHNICAL ENGINEERING
BASIS OF DESIGN REPORT
Rodriguez Property Slope Stabilization
Edmonds, Washington
Prepared for: Raphael Rodriguez
Project No. 230007 • August 30, 2023 • Final
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CONSULTING
GEOTECHNICAL ENGINEERING
BASIS OF DESIGN REPORT
Rodriguez Property Slope Stabilization
Edmonds, Washington
Prepared for: Raphael Rodriguez
Project No. 230007 • August 30, 2023 • Final
Aspect Consulting, LLC
Matthew von der Ahe, L.E.G.
Project Engineering Geologist
mvonderahe@aspectconsulting.com
Julia Martz, E.I.T.
Staff Geotechnical Engineer
jmartz@aspectconsulting.com
30/23
Erik O. Andersen, PE
Principal Geotechnical Engineer
eandersen@aspectconsulting.com
V:\230007 Rodriguez Property Geotech\Deliverables\Basis of Design Report\Rodriguez basis of design report_08302023.docx
ASPECT CONSULTING
Contents
1 Introduction.................................................................................................1
1.1 Project Background and Description.......................................................1
2 Geotechnical Engineering Conclusions and Recommendations.............2
2.1 Conclusions and Recommendations.......................................................2
2.2 Soldier Pile Wall Design...........................................................................3
2.2.1 Design Specifications.........................................................................3
2.2.2 Soil Engineering Properties................................................................3
2.2.3 Lateral Earth Pressures.......................................................................4
2.2.4 Soldier Pile Spacing, Shaft Diameter, Section, and Length .............4
2.2.5 Global Stability...................................................................................5
3 Earthwork and Soldier Pile Construction..................................................6
3.1 General......................................................................................................6
3.2 Temporary Excavations and Shoring......................................................6
3.3 Soldier Piles..............................................................................................7
3.4 Wall Backfill...............................................................................................8
3.5 Weather Considerations...........................................................................8
4 References....................................................................................................9
5 Limitations.................................................................................................10
List of Tables (in text)
1 Summary of Soil Engineering Properties...................................................3
2 Lateral Earth Pressures by Soil Unit..........................................................4
List of Appendices
A Shoring Suite Outputs
B Report Limitations and Guidelines for Use
PROJECT NO. 230007 • AUGUST 30, 2023 FINAL i
ASPECT CONSULTING
1 Introduction
1.1 Project Background and Description
The Project background and description are discussed in detail in the Geotechnical
Report, issued 8/28/2023 (Aspect, 2023). A summary of the Project follows.
The property at 18418 Olympic View Drive in Edmonds, Washington (Site) lies at the
top of steep, northwest -facing slope above Puget Sound. Site improvements include a
single-family residence with attached deck and garage, a gazebo, and other associated
infrastructure. On December 27, 2022, stormwater runoff from upslope resulted in a
debris flow that impacted the Site residence and caused a landslide on the steep slope to
the west of the residence. As a result of the landslide, material was scoured from the bluff
edge, including large boulders and cyclone fence footings, and channels were incised into
the steep bluff. The foundation for the gazebo at the northwestern corner of the Site was
undermined. Unless measures are taken to stabilize the slope, future failures or erosion
will result in further damage to the gazebo and loss of yard.
Review of historical photos and documents reveals that surficial slides, similar in scale to
the December 2022 event, have occurred at least three times over the past few decades on
the property and the adjacent property to the south. Bare soil on the slope and beach
waterward of the residence, presumably stripped of vegetation by slope failure, are
visible in aerial and oblique imagery from 1972 and 1977, and a written account of a
stormwater-triggered slope failure in 1980 exists. The gully that extends downslope near
the northern property boundary is recorded in a topographic map from 1958.
The client wishes to restore the top of the slope to protect the existing yard, landscaping,
gazebo, and other site improvements to the greatest extent possible. It is Aspect's
recommendation that a new soldier pile wall along the top of the slope will allow
retention of most of the existing yard, gazebo, and other features and will slow future
slope retreat.
PROJECT NO. 230007 • AUGUST 30, 2023 FINAL
ASPECT CONSULTING
2 Geotechnical Engineering Conclusions and
Recommendations
Our geotechnical engineering conclusions and recommendations for the Project are
presented in detail in the following sections.
2.1 Conclusions and Recommendations
We have identified the following primary geotechnical elements and summarized our
conclusions and recommendations below:
A landslide occurred on December 27, 2022, after an extended period of high -
intensity precipitation following a snow event. During the slide, surficial material
up to several feet thick eroded and slid from the top of the steep slope. The
material, consisting of soil, vegetation, and parts of fencing and retaining
structures, was deposited on the middle and lower parts of the steep slope. The
slide resulted in bare soil and a steep head scarp along the steep slopes, as well as
tension cracks, soil subsidence, damage to landscaping and fencing, and partial
undermining of the corner of the gazebo. The head scarp is approximately 40 feet
from the closest part of the residence and immediately adjacent to the closest part
of the gazebo. The residence was not damaged by the slide, but the edge of the
gazebo was undermined and settled fractionally.
• The Site subsurface consists of fill over two different glacially consolidated
geologic units: Transition Beds and Olympia Gravels (Minard, 1983). Seismicity
on a nearby strand of the Southern Whidbey Island Fault in the last several
thousand years has disturbed and weakened the glacially consolidated units.
• We did not encounter groundwater in any of our explorations, although we did
observe localized samples with high relative moisture content that could be
indicative of localized perched groundwater. In our opinion, earthwork in these
soils can be completed with conventional construction equipment.
• The project will include a soldier pile wall designed for up to 10 feet of exposed
height. Initial expected wall height is indicated in the construction drawings.
Soldier pile wall design requirements are provided within this report.
• Lagging between soldier piles will be treated timber. Additional lagging can be
added over the wall's design life if erosion occurs and the bottom lagging board
is undermined.
FINAL PROJECT NO. 230007 • AUGUST 30, 2023
ASPECT CONSULTING
2.2 Soldier Pile Wall Design
The following sections present our design assumptions and the results of our design
analyses for the soldier pile wall.
2.2.1 Design Specifications
Based on our understanding of the Site subsurface conditions and our experience with
soldier pile wall design, we developed the following list of specifications for the design
of the soldier pile wall:
• The wall will be a cantilevered soldier pile wall with pile lengths of 30 feet and
an exposed height of up to 10 feet. Soldier piles will be W 14x61 sections
installed into drilled shafts that are backfilled with lean concrete or controlled
density fill. Soldier piles will be installed on 8-foot, center -to -center spacings.
• The soldier pile wall will retain the existing fill and disturbed native soils at the
site up to an assumed long term exposed height of 10 feet.
• The wall has been designed to consider the vertical surcharge pressure from the
nearby deck, trail, and other existing site improvements.
• The wall is not designed for incremental seismic loading. This is in accordance
with design guidance from Washington State Department of Transportation
Geotechnical Design Manual Section 6-1.2.1 (WSDOT, 2022).
• The upslope/retained side of the wall will be backfilled with freely draining sand
and gravel, and there will be gaps in the timber lagging. Thus, the wall will be
sufficiently pervious such that water pressure will not develop on the wall.
• Lagging for the wall will be treated timber. Treated timber lagging was chosen
because of ease of construction, moderate cost, durability (will last for decades),
and ease of maintenance and replacement.
2.2.2 Soil Engineering Properties
Based on the subsurface explorations, laboratory testing, and our geologic expertise, we
designated the soil/material units and assigned the engineering parameters for our
geotechnical analyses, as shown in Table 1.
Table 1. Summa of Soil Engineering Properties
Geologic Unit
Unit Weight (pcf)
Strength Parameters
Friction Angle
(deg)
Cohesion
(psf)
Fill
115
28
0
Transitional Beds
125
32
200
Olympia Gravels
130
36
500
Notes: pcf = pounds per cubic foot; psf = pounds per square foot; deg = degrees
PROJECT NO. 230007 • AUGUST 30, 2023 FINAL
ASPECT CONSULTING
These soil engineering parameters were back -calculated with a sensitivity analysis by
modeling the pre -failure slope using the subsurface data collected at the Site, and two-
dimensional limit equilibrium methods within the software program Slide2 (Rocscience,
2022). With these parameters and the pre -landslide slope conditions, the calculated factor
of safety (FS) was approximately 1.0, which indicates a marginally stable slope
conducive to failing. These values are also consistent with our geologic and engineering
knowledge and experience.
2.2.3 Lateral Earth Pressures
Using the design assumptions and soil engineering properties listed in Table 1 above, we
developed the lateral earth pressures shown in Table 2 for the design of the soldier pile
wall. The active earth pressures are appropriate for the retained materials described
above. The allowable passive earth pressure includes a factor of safety of 1.5, which was
appropriately reduced to account for the sloping ground surface in front of the wall. In
our design, we assumed the allowable passive earth pressure will act over two -and -a -half
concreted pile diameters (2.5d), or the pile center -to -center spacing, whichever is less.
Table 2. Lateral Earth Pressures by Soil Unit
Geologic Unit
Active Earth Pressure
(Pcf)'
Passive Earth Pressure
(Pcf)
Fill
41.5
N/A
Transitional Beds
38.4
154
Olympia Gravels
33.8
500
Notes:
1. pcf = pounds per cubic foot
2. Passive earth pressure of Loose Disturbed Transitional Beds (Qtb) accounts for the assumed
2H:1 V sloping ground surface in front of the wall after construction
A uniform vertical surcharge from site improvements (trail, deck, etc.) of 250 pounds per
square foot (psf) was converted to a uniform lateral earth pressure applied over the height
of the wall. The assumed long term design lateral earth pressure excludes loads from
heavy construction equipment and soil and material stockpiles. If the contractor's means
and methods will subject the wall to significant construction -related surcharge loading,
Aspect should be contacted to evaluate.
2.2.4 Soldier Pile Spacing, Shaft Diameter, Section, and Length
Using the design assumptions, soil engineering properties (Table 1), and lateral earth
pressures (Table 2) listed above, we evaluated soldier pile section and embedment
requirements to resist bending, using the Shoring Suite computer software program
(CivilTech, 2020). We evaluated various combinations of shaft diameter and pile center
to -center spacing for the two design sections.
Our analysis and design calls for 30-foot-long W 14x61 beams on 8-foot-centers and set
in 24-inch diameter shafts. Calculation results are provided in Appendix A.
FINAL PROJECT NO. 230007 • AUGUST 30, 2023
ASPECT CONSULTING
2.2.5 Global Stability
We evaluated global stability of the soldier pile wall (the potential for failures to pass
through the slope below the wall) using Slide2. We evaluated global stability for the
critical wall section (i.e., the 10-foot-tall wall design section) under static conditions.
The Slide2 program performs slope stability computations based on the modeled slope
conditions and calculates a factor of safety against slope failure. A minimum factor of
safety of 1.5 under static conditions is considered acceptable by industry standards.
Our analysis shows the soldier pile wall of the selected design pile and embedment at the
critical section will have a static global factor of safety greater than 1.5, thus confirming
sufficient global stability.
PROJECT NO. 230007 • AUGUST 30, 2023 FINAL
ASPECT CONSULTING
3 Earthwork and Soldier Pile Construction
3.1 General
Soldier pile wall construction will be somewhat challenging at this residential property.
Tracked construction equipment with a narrow footprint will need to be utilized. Some
landscaping features and planted vegetation will need to be removed or modified to
provide construction access.
Site preparation along the wall will require minor grading to create a level bench that the
soldier pile drill rig will operate and move along. Benching will likely be done by
creating a small cut. Soil generated by this operation will need to be stockpiled at an
approved upland location.
Soldier pile shaft excavation will extend through weak surficial materials that are prone
to sloughing and caving. As such, the Contractor shall be prepared to utilize temporary
casing in the upper portion of each soldier pile.
Shaft excavation and soldier pile placement should be sequenced in a "hopscotch"
manner, meaning, for example, piles 3, 5, and 7 may be installed and concreted one day,
and the following day, piles 2, 4, and 6 may be installed and concreted. This sequence
will reduce the risk of shaft blowout and communication of wet concrete between
adjacent shafts.
Although not observed in our subsurface explorations, debris or oversize particles
(including boulders) could be present in the fill and native soil. The contractor should be
prepared to handle and remove obstructions during drilled shaft excavation.
Finally, construction of the Project should be in accordance with the notes and details
shown on the Project Plans. The integrity and performance of the soldier pile wall will
depend on proper construction. Aspect should be retained during construction to provide
inspection of soldier pile installation and placement of backfill to verify the work is
completed in accordance with the plans and our recommendations.
3.2 Temporary Excavations and Shoring
We anticipate a minor cut will be required to create a working surface for soldier pile
construction. The extent and depth of any temporary cut(s) will be determined by the
contractor. Temporary excavation slope stability will be the Contractor's responsibility.
The Site soil classifies as Type C Soil in accordance with the Washington Administrative
Code (WAC) 296-155 Part N (WAC, 2016). Temporary cut slopes in Type C Soil shall
not be steeper than 1.5H:1 V. The presence of water seepage may require that slopes be
flattened further or shored to remain stable.
We also recommend the following for temporary excavations and slopes:
• Surface water should be diverted away from slopes.
• Slopes should be protected using plastic sheeting, flash coating, or tarps to
control erosion and stability, as necessary.
FINAL PROJECT NO. 230007 • AUGUST 30, 2023
ASPECT CONSULTING
• The duration that excavations or slopes are open should be minimized.
• Traffic, equipment, and material stockpiles should not be allowed near the top of
excavations or slopes.
• The conditions of the excavations and slopes should be periodically observed by
a competent person who is a representative of the contractor to evaluate safety
and stability.
The contractor shall be responsible for reviewing the subsurface data shown on the
exploration logs included in the geotechnical report for the site (Aspect, 2023). The
contractor shall also be responsible for designing and constructing any temporary shoring
to support temporary excavations, if needed, based on the means and methods of
construction.
The contractor should be prepared to encounter and manage groundwater seepage in
excavations. Groundwater seepage is most likely to emanate from excavations that
intersect the contact between the fill and native soil. Groundwater seepage may also
emanate from sandy lenses/zones in the native glacially consolidated soil where exposed
through excavation. The contractor shall be prepared to utilize temporary casing in the
drilled shafts where weak soil or groundwater seepage don't allow the shaft sidewalls to
stand unsupported.
3.3 Soldier Piles
In general, we provide the following considerations and recommendations for soldier pile
construction:
The contractor should be prepared to encounter groundwater seepage in the
soldier pile shafts. Accordingly, the contractor should be prepared to use
temporary casing or other methods to maintain an open hole and prevent caving
and soil loss. If there is more than 12 inches of standing water in the base of the
shaft, concrete must be placed with a tremie pipe (so as to displace the water
upwards out of the shaft as the concrete is pumped in from the bottom up).
The bottom of the soldier pile shafts should be relatively undisturbed and clear of
loose/slough soils and debris prior to placing the beams and filling the shafts with
concrete.
• Sequential shafts should not be drilled on the same working shift. During each
working shift, every other shaft should be drilled, and the concrete should be
placed and allowed to cure for at least 12 hours before adjacent shafts are drilled.
Excavation for the installation of lagging should be accomplished in 4-foot
(maximum) vertical lifts. When the first lift of lagging is complete, the contractor
can continue with the excavation in 4-foot lifts until all required lagging has been
installed. If caving soils are encountered during excavation for lagging, the
contractor should be prepared to excavate and install the lagging in shorter lifts.
All excavations should be supported by lagging the same working day.
PROJECT NO. 230007 • AUGUST 30, 2023 FINAL
ASPECT CONSULTING
• Any voids that form behind the wall due to caving soils during excavation for
lagging should be backfilled with free -draining granular material approved by the
geotechnical engineer. Voids should be backfilled the same working day.
3.4 Wall Backfill
Wall backfill should be placed on firm and unyielding subgrade evaluated and approved
by the Engineer. Subgrades should be clear of all construction debris, loose or disturbed
soil, and standing water prior to backfill placement. Soft or disturbed subgrade areas
identified during evaluation should be removed to expose undisturbed subgrade to the
satisfaction of the Engineer.
Wall backfill should consist of imported material meeting the requirements for Gravel
Backfill for Walls, WSDOT Standard Specification 9-03.12(2) (WSDOT, 2023) at the
locations and elevations specified in the plans. Wall backfill should be compacted so as
to fill all voids and so the soil behind the wall is adequately retained.
Site -derived soils are not suitable for re -use as wall backfill material.
3.5 Weather Considerations
Given the nature of this Site, soldier pile wall construction should be scheduled to occur
outside of the wet season months of November through March. Site access, grading, and
associated work at the crest of this very steep slope would be risky if done during the
winter wet season. Therefore, we recommend the Permit documents require this project
to be done during the dry season months of April through October.
Even during the dry season months, periods of rainfall are likely in the Pacific Northwest.
The Site soils are moisture sensitive and will be difficult to handle during wet weather.
Tracked equipment working on a narrow bench at the crest of a failed slope will be at a
heighted risk of sliding down the slope. Therefore, the contract documents should require
work to shut down if substantial rain (defined here as'/2 inch or more rainfall in a 24-hour
period) is falling or is forecast to fall.
These additional recommendations should be followed:
• Site preparation and associated earthwork should be completed in small sections to
minimize exposure to rainfall.
• Exposed freshly cut soil surfaces should be covered or protected and should not be
left open and exposed.
• Material used as structural fill should consist of clean, granular soil containing less
than 7 percent fines.
• Freshly exposed soil surfaces within the construction area should be roughened and
compacted by walking tracked equipment over them. Soils that become wet and
muddy shall be stripped and replaced with clean granular materials.
• Excavation and placement of fill should be observed by Aspect to verify that all
unsuitable materials are removed, and suitable compaction is achieved.
• Local best management practices (BMPs) for erosion control should be strictly
followed.
FINAL PROJECT NO. 230007 • AUGUST 30, 2023
ASPECT CONSULTING
4 References
Aspect Consulting LLC (Aspect), 2023, Geotechnical Report, Niesel Residence, issued
8/28/2023.
CivilTech, 2020, Shoring Suite, version 8.21
Minard, J.P., 1983, Geologic Map of the Edmonds East and Part of the Edmonds West
Quadrangles, Washington, USGS, Miscellaneous Field Studies Map MF-1541.
Rocscience, 2022, Slide 8.019 and 8.020 Analysis Program, accessed June 2023.
Washington Administrative Code (WAC), 2016, April 19, 2016.
Washington State Department of Transportation (WSDOT), 2023, Standard
Specifications for Road, Bridge, and Municipal Construction, M 41-10.
Washington State Department of Transportation (WSDOT), 2022, Geotechnical Design
Manual, M 46-03.16.
PROJECT NO. 230007 • AUGUST 30, 2023 FINAL
ASPECT CONSULTING
5 Limitations
Work for this project was performed for Raphael Rodriguez (Client), and this report was
prepared consistent with recognized standards of professionals in the same locality and
involving similar conditions, at the time the work was performed. No other warranty,
expressed or implied, is made by Aspect Consulting, LLC (Aspect).
Recommendations presented herein are based on our interpretation of site conditions,
geotechnical engineering calculations, and judgment in accordance with our mutually
agreed -upon scope of work. Our recommendations are unique and specific to the project,
site, and Client. Application of this report for any purpose other than the project should
be done only after consultation with Aspect.
Variations may exist between the soil and groundwater conditions reported and those
actually underlying the site. The nature and extent of such soil variations may change
over time and may not be evident before construction begins. If any soil conditions are
encountered at the site that are different from those described in this report, Aspect
should be notified immediately to review the applicability of our recommendations.
Risks are inherent with any site involving slopes and no recommendations, geologic
analysis, or engineering design can assure slope stability. Our observations, findings, and
opinions are a means to identify and reduce the inherent risks to the Client.
It is the Client's responsibility to see that all parties to this project, including the designer,
contractor, subcontractors, and agents, are made aware of this report in its entirety. If
project developments result in changes from the preliminary project information, Aspect
should be contacted to determine if our recommendations contained in this report should
be revised and/or expanded upon.
The scope of work does not include services related to construction safety precautions.
Site safety is typically the responsibility of the contractor, and our recommendations are
not intended to direct the contractor's site safety methods, techniques, sequences, or
procedures. The scope of our work also does not include the assessment of environmental
characteristics, particularly those involving potentially hazardous substances in soil or
groundwater.
All reports prepared by Aspect for the Client apply only to the services described in the
Agreement(s) with the Client. Any use or reuse by any party other than the Client is at the
sole risk of that party, and without liability to Aspect. Aspect's original files/reports shall
govern in the event of any dispute regarding the content of electronic documents
furnished to others.
Please refer to Appendix B titled "Report Limitations and Guidelines for Use" for
additional information governing the use of this report.
10 FINAL PROJECT NO. 230007 • AUGUST 30, 2023
APPENDIX
Shoring Suite Outputs
Rodriguez Soldier Pile Wall
Depth(ft)
10
10
15
20
25
30 I 0 1 ksf
I
<ShoringSuite> CIVILTECH SOFTWARE USA www.civiltech.com
Licensed to 4324324234 3424343 Date: 8/28/2023
File: S:\Rodriguez Residence 230007\Report Drafts\Draft\Basis of design report\Appendix A - Shoring Suite Output
Wall Height=10.0 Pile Diameter=2.0 Pile Spacing=8.0 Wall Type: 2. Soldier Pile, Drilled
PILE LENGTH: Min. Embedment=17.12 Min. Pile Length=27.12
MOMENT IN PILE: Max. Moment=238.73 per Pile Spacing=8.0 at Depth=17.98
PILE SELECTION:
Request Min. Section Modulus = 86.8 in3/pile=1422.56 cm3/pile, Fy= 50 ksi = 345 MPa, Fb/Fy=0.66
-> Piles meet Min. Section Requirements: Top Deflection is shown in (in)
W10X88 (1.29) HP12X74 (1.21) W12X65 (1.29) HP13X73 (1.09) HP14X73 (0.95)
W14X61 (1.08) W16X57 (0.91) HP16X88 (0.62) W16X89 (0.53) HP16X101 (0.53)
W16X100 (0.46) HP16X121 (0.44) W18X50 (0.86) HP18X135 (0.31)
DRIVING PRESSURES (ACTIVE, WATER, & SURCHARGE):
Z1 P1 Z2 P2 Slope
0 0 10 0.415 0.0415
10 0.384 15 0.576 0.0384
15 0.507 100 3.380 0.0338
*Hous
0 0.077 10 0.077
PASSIVE PRESSURES: Pressures below will be divided by a Factor of Safety =1.5
Z1 P1 Z2 P2 Slope
10 0 15 0.770 0.154
15 2.5 100 45.00 0.500
ACTIVE SPACING:
No. Z depth Spac4
1 0.00 8.00
2 10.00 2.00
PASSIVE SPACING:
No. Z depth Spacir
1 10.00 4.00
UNITS: Width, Spacing, Diameter,Length,and Depth - ft; Force - kip; Moment - kip-ft
Friction,Bearing,and Pressure - ksf; Pres. Slope - kip/ft3; Deflection - in
APPENDIX B
Report Limitations and Guidelines
for Use
REPORT LIMITATIONS AND GUIDELINES FOR USE
Geoscience is Not Exact
The geoscience practices (geotechnical engineering, geology, and environmental science) are far
less exact than other engineering and natural science disciplines. It is important to recognize this
limitation in evaluating the content of the report. If you are unclear how these "Report Limitations
and Guidelines for Use" apply to your project or property, you should contact Aspect Consulting,
LLC (Aspect).
This Report and Project -Specific Factors
Aspect's services are designed to meet the specific needs of our clients. Aspect has performed the
services in general accordance with our agreement (the Agreement) with the Client (defined under
the Limitations section of this project's work product). This report has been prepared for the
exclusive use of the Client. This report should not be applied for any purpose or project except the
purpose described in the Agreement.
Aspect considered many unique, project -specific factors when establishing the Scope of Work for
this project and report. You should not rely on this report if it was:
• Not prepared for you;
• Not prepared for the specific purpose identified in the Agreement;
• Not prepared for the specific subject property assessed; or
• Completed before important changes occurred concerning the subject property, project, or
governmental regulatory actions.
If changes are made to the project or subject property after the date of this report, Aspect should be
retained to assess the impact of the changes with respect to the conclusions contained in the report.
Reliance Conditions for Third Parties
This report was prepared for the exclusive use of the Client. No other party may rely on the product
of our services unless we agree in advance to such reliance in writing. This is to provide our firm
with reasonable protection against liability claims by third parties with whom there would
otherwise be no contractual limitations. Within the limitations of scope, schedule, and budget, our
services have been executed in accordance with our Agreement with the Client and recognized
geoscience practices in the same locality and involving similar conditions at the time this report
was prepared.
Property Conditions Change Over Time
This report is based on conditions that existed at the time the study was performed. The findings
and conclusions of this report may be affected by the passage of time, by events such as a change in
property use or occupancy, or by natural events, such as floods, earthquakes, slope instability, or
groundwater fluctuations. If any of the described events may have occurred following the issuance
of the report, you should contact Aspect so that we may evaluate whether changed conditions affect
the continued reliability or applicability of our conclusions and recommendations.
ASPECT CONSULTING
Geotechnical, Geologic, and Environmental Reports Are Not
Interchangeable
The equipment, techniques, and personnel used to perform a geotechnical or geologic study differ
significantly from those used to perform an environmental study and vice versa. For that reason, a
geotechnical engineering or geologic report does not usually address any environmental findings,
conclusions, or recommendations (e.g., about the likelihood of encountering underground storage
tanks or regulated contaminants). Similarly, environmental reports are not used to address
geotechnical or geologic concerns regarding the subject property.
We appreciate the opportunity to perform these services. If you have any questions, please contact
the Aspect Project Manager for this project.