Report GC�c,SrC c-a - K5
Carlson Geotechnical Bend Office (541)330915 �S0
Eugene Office (541)345-0289
A division of Carlson Testing, Inc. Salem Office (503) 589-1252 GEOTECHNICAL
Phone: (503)601-8250 OFFICE Card Office (503)684-3460
www.carlsontestinq.com
RECEIVED
OCT 282020
CITY OF TIGARD
BUILDING DIVISION
Updated Geotechnical Report
Crescent Grove Cemetery Administration Building
9925 SW Greenburg Road
Tigard, Oregon
CGT Project Number G2005381
Prepared for
Nancy Felton
Crescent Grove Cemetery
9925 SW Greenburg Road
Tigard, Oregon 97223
October 27, 2020
Office: 18270 SW Boones Ferry Road, Suite 6, Durham, Oregon 97224
Mailing: P.O. Box 230997, Tigard, Oregon 97281
Carlson Geotechnical Bend Office (541)330-9155 el.
R 0
Eugene (541)345-0289
A division of Carlson Testing, Inc. Salem Office (503) 589-1252
Phone: (503)601-8250 GEOTECHNICAL
Tigard Office (503)684-3460
www.carisontesting_cum _. "
October 27, 2020
Nancy Felton
Crescent Grove Cemetery
9925 SW Greenburg Road
Tigard, Oregon 97223
Updated Geotechnical Report
Crescent Grove Cemetery Administration Building
9925 SW Greenburg Road
Tigard, Oregon
CGT Project Number G2005381
Dear Ms. Felton:
Carlson Geotechnical (CGT), a division of Carlson Testing, Inc. (CTI), is pleased to submit this updated
geotechnical report for the proposed Crescent Grove Cemetery Administration Building project. The site is
located at 9925 SW Greenburg Road in Tigard, Oregon. We performed our work in general accordance with
CGT Proposal GP9138R1, dated October 14, 2020. Written authorization for our services was received on
October 14, 2020.
We appreciate the opportunity to work with you on this project. Please contact us at (503) 601-8250 if you
have any questions regarding this report.
Respectfully Submitted,
CARLSON GEOTECHNICAL
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EXPIRES: 4d136/Zp'ZZ-
Morgan Masley, EIT Brad M. Wilcox, P.E., G.E.
Geotechnical Staff II Principal Geotechnical Engineer
mmasley(ct7carlsontesting.com bwilcax,Acarlsontestinq.com
Doc ID: G:\GEOTECH\PROJECTS12020 Projects\G2005381 -Crescent Grove Cemetry Building - Updated Geotechnical Report1008-
Deliverables\Report\G2005381 Updated Geotechnical.docx
Office: 18270 SW Boones Ferry Road,Suite 6, Durham, Oregon 97224
Mailing: P.O. Box 230997,Tigard, Oregon 97281
Crescent Grove Cemetery Administration Building
Tigard, Oregon
CGT Project Number G2005381
October 27, 2020
TABLE OF CONTENTS
1.0 INTRODUCTION 4
1.1 Project Information 4
1.2 Scope of Services 4
2.0 SITE SURFACE CONDITIONS 4
3.0 SUBSURFACE CONDITIONS 5
4.0 CONCLUSIONS 5
5.0 UPDATED RECOMMENDATIONS 6
5.1 Seismic Site Class 6
5.2 Seismic Design 6
6.0 LIMITATIONS & CLOSURE 6
ATTACHMENTS
Site Plan Figure 1
Site Photographs Figure 2
Reproduced 2006 Test Pit Logs Appendix A
Carlson Geotechnical Page 3 of 6
Crescent Grove Cemetery Administration Building
Tigard, Oregon
CGT Project Number G2005381
October 27, 2020
1.0 INTRODUCTION
Carlson Geotechnical (CGT), a division of Carlson Testing, Inc. (CTI), is pleased to submit this updated
geotechnical report for the proposed Crescent Grove Cemetery Administration Building project. The site is
located at 9925 SW Greenburg Road in Tigard, Oregon.
1.1 Project Information
CGT previously performed a geotechnical investigation for a previous project at the Cemetery, the results of
which were presented in our report titled "Preliminary Geotechnical Investigation," dated September 27, 2006
(CGT Project Number G0602906). A PDF copy of that report was recently conveyed to us by Giulietti /
Schouten AIA Architects (GSA).
Based on the most recent development plans for the site, prepared by GSA, dated October 9, 2020, we
understand that the current project includes demolition and removal of an existing building at the west central
portion of the site, and construction of a new Administration Building with appurtenant structures in the same
general area. The layout of the proposed development is shown on the attached Site Plan, Figure 1. The
administration building will be one- to two-stories, wood-framed, and incorporate post-and-beam floor
construction (crawlspaces). No below-grade levels (basements) are planned. Permanent grade changes at
the site will be minimal.
The building will be supported by conventional shallow, continuous wall (strip) and individual (column pad)
foundations. Per Sheet S0.01 of the plans, the foundations were designed based on an allowable soil
bearing pressure of 2,000 pounds per square foot (psf). In addition, as shown on that plan sheet, the Seismic
Site Class was assigned as Site Class D.
1.2 Scope of Services
Our scope of work included a visit to the site in order to determine if site conditions remained consistent with
those observed during our previous field investigation. Upon confirmation of site conditions, we prepared this
updated geotechnical report to address geotechnical considerations relative to the current (2019) Oregon
Structural Specialty Code (OSSC). No supplemental subsurface explorations were completed for this
assignment.
2.0 SITE SURFACE CONDITIONS
We visited the site on October 15, 2020, in order to confirm existing site conditions. The Crescent Grove
Cemetery consisted of one tax lot totaling approximately 21 acres, and was bordered to the north, south, and
west by Washington Square Mall, and to the east by SW Greenburg Road. The cemetery property generally
sloped to the northwest at gradients less than 10H:1V (Horizontal: Vertical). The majority of the cemetery
property was occupied by burial plots, with the exception of the northern approximately 150 feet of the site,
and the northwestern corner of the property. Several mausoleum structures occupied the western portion of
the property. The area of the proposed Administration Building, hereafter referred to as the "site", was
relatively level to gently descending to the north and occupied by an office building and grass lawns.
The site surface conditions were consistent with those previously observed during our previous investigation
in 2006. Site layout and surface conditions at the time of our recent (October 2020) visit are shown on the
attached Site Photographs, Figure 2.
Carlson Geotechnical Page 4 of 6
Crescent Grove Cemetery Administration Building
Tigard, Oregon
CGT Project Number G2005381
October 27, 2020
3.0 SUBSURFACE CONDITIONS
As part of our 2006 field investigation, we excavated a total of ten test pits within the cemetery property. Two
of the test pits, designated as TP-9 and TP-10, were excavated in relative close proximity to the proposed
Administration Building. The logs of those explorations have been reproduced and are included in the
attached Appendix A. The following summarizes each subsurface material encountered in those test pits.
Silt with Sand Topsoil (OL): Silt with sand topsoil was encountered at the surface of each test pit and
extended to depths of about 3A to 1 foot bgs. This soil was generally hard, gray to light brown and moist.
Undocumented Silt with Sand Fill (ML Fill): Undocumented silt with sand fill was encountered below the
topsoil in each test pit and extended to depths of about 4 to 5 feet bgs. Undocumented fill refers to materials
placed without (available) records of subgrade conditions or evaluation of compaction. This soil was
generally hard, brown to orange-brown, moist, and exhibited some mottling. Various debris, including
concrete and PVC pipes, were encountered at intermittent depths within this soil.
Silty Clay (CL-ML): Silty clay was encountered below the undocumented fill in each test pit and extended to
the full depths explored, up to about 6 feet bgs. This soil was generally stiff to very stiff, blue to grey, moist,
and exhibited low plasticity.
No groundwater or caving was encountered within the depths explored in the two test pits referenced above
and excavated in late August 2006.
4.0 CONCLUSIONS
Based on the results of the 2006 test pit explorations, our recent site observations, and analyses, the site
may be developed as described in Section 1.1 of this report. Satisfactory subgrade support for shallow
foundations and floor slabs associated with the proposed Administration Building can be achieved by the
native, stiff to better, silty clay (CL), or new structural fill that is properly placed and compacted on this
material during construction. This soil was encountered at depths of about 4 to 5 feet bgs within test pits
TP-9 and TP-10 completed in August 2006.
As indicated in our 2006 geotechnical report, it appears the existing silt with sand fill (ML Fill)was placed and
compacted in a controlled manner. Earthwork records (e.g. compaction testing reports, field observation
reports, etc.) could be sought to provide additional information regarding previous grading at the site. In the
absence of such records, due to the presence of various debris (concrete, PVC pipes), we recommend the
undocumented fill materials be completely over-excavated and replaced with structural fill in conformance
with the recommendations presented in the 2006 geotechnical report. If the client and project team desire to
utilize the existing silt with sand fill for support of foundations and/or floor slabs, supplemental investigation
(e.g. test pits, Wildcat dynamic cone penetrometer tests) are recommended to refine its conditions and
suitability to support proposed improvements. Such supplemental investigation could reasonably be
performed by the project geotechnical engineer at the onset of construction, once the earthwork contractor
has mobilized to the site and the existing office building has been removed.
Carlson Geotechnical Page 5 of 6
Crescent Grove Cemetery Administration Building
Tigard, Oregon
CGT Project Number G2005381
October 27, 2020
The following section provides updated recommendations for seismic design criteria based on the 2019
Oregon Structural Specialty Code (OSSC). These recommendations supersede those presented in the
"Seismic Design" section of the referenced 2006 report.
5.0 UPDATED RECOMMENDATIONS
5.1 Seismic Site Class
Section 1613.2.2 of the 2019 OSSC requires that the determination of the seismic site class be in
accordance with Chapter 20 of the American Society of Civil Engineers Minimum Design Loads for Buildings
and Other Structures (ASCE 7-16). We have assigned the site as Site Class D ("Stiff Soil") based on review
of geologic mapping, subsurface conditions encountered during our August 2006 investigation, and
experience in the project area.
5.2 Seismic Design
Earthquake ground motion parameters for the site were obtained in accordance with the 2019 OSSC using
the Seismic Hazards by Location calculator on the ATC website'. The site Latitude 45.449613° North and
Longitude 122.778608°West were input as the site location. The following table shows the recommended
seismic design parameters for the site.
Table 1 Seismic Ground Motion Values
Parameter Value
Spectral Acceleration,0.2 second (S5) 0.865g
Mapped Acceleration Parameters
Spectral Acceleration, 1.0 second(Si) 0.397g
Coefficients Site Coefficient,0.2 second(FA) 1.154
(Site Class D) Site Coefficient, 1.0 second(Fv)1 1.903
Adjusted MCE Spectral MCE Spectral Acceleration,0.2 second(SMs) 0.998g
Response Parameters MCE Spectral Acceleration,1.0 second(SMi) 0.755g
Design Spectral Acceleration,0.2 second(Sps) 0.666g
Design Spectral Response Accelerations Design Spectral Acceleration,1.0 second(Sp,) 0.503g
Seismic Design Category(Risk Category II) D
Value determined from 2019 OSSC Table 1613.2.3(2).
6.0 LIMITATIONS& CLOSURE
This report should be attached to, and considered part of, the referenced September 27, 2006, geotechnical
report. As such, the limitations detailed in the referenced report apply to this updated report. We appreciate
the opportunity to work with you on this project. Please contact us at 503.601.8250 if you have any questions
regarding this report.
Applied Technology Council (ATC), 2020. USGS seismic design parameters determined using "Seismic Hazards by Location,"
accessed October 2020,from the ATC website https://hazards.atcouncil.orq/.
Carlson Geotechnical Page 6 of 6
CRESCENT GROVE CEMETERY ADMINISTRATION BUILDING- TIGARD, OREGON FIGURE 1 _
Project Number G2005381 Site Plan
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® Orientation of October 2020 site photographs shown on Figure 2 NOTES:Drawing based on observations made while on site and site
503-601-8250 plans produced by Giuletti 1 Schouten AIAArchitects,dated October 9,
LP-1 September 2006 test pit exploration 2020. Test pit locations approximated based on review of 2006
Drafted by:mbm geotechnical report(see text for further discussion).
CRESCENT GROVE CEMETERY ADMINISTRATION BUILDING - TIGARD, OREGON FIGURE 2
Project Number G2005381 Site Photographs
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503503-6® Photographs were taken for confirmation of site conditions.
Dra]ed by rAlA
Carlson Geotechnical Bend Office (541)330-9155 tiskL _
Eugene Office (541)345-0289 G� r + "_v
A division of Carlson Testing, Inc. Salem Office (503)589-1252 GEOTECHNICAL
Phone: (503)601-8250 Tigard Office (503)684-3460
www.carlsontesting.com
Appendix A: Reproduced 2006 Test Pit Logs
Crescent Grove Cemetery Administration Building
9925 SW Greenburg Road
Tigard, Oregon
CGT Project Number G2005381
October 27, 2020
Prepared For:
Nancy Felton
Crecent Grove Cemetery
9925 SW Greenburg Road
Tigard, Oregon 97223
Prepared by
Carlson Geotechnical
Logs of 2006 Test Pits TP-9 and TP-10 Attached
Office: 18270 SW Boones Ferry Road, Suite 6, Durham, Oregon 97224
Mailing: P.O. Box 230997, Tigard, Oregon 97281
Carlson Geotechnical FIGURE 13
p. O 7185 SW Sandburg Street, Suite 110
"'L IT _ Tigard,OR 97223 TEST PIT NUMBER TP-9
I Telephone; (503)601-8250
soa•eot•sasa Fax: (503)601-8254 PAGE 1 OF 1
CLIENT Crescent Grove Cemetery PROJECT NAME Crescent Grove Cemetery Expansion
IPROJECT NUMBER G0602906 PROJECT LOCATION 9925 S.W.Greenberg Road, Tigard.OR 97223
DATE STARTED 8/25/06 COMPLETED 8t25106 GROUND ELEVATION TEST PIT SIZE
EXCAVATION CONTRACTOR Client GROUND WATER LEVELS:
IEXCAVATION METHOD Test Pit AT TIME OF EXCAVATION ---
LOGGED BY Gabe Burgess CHECKED BY Ryan Houser AT END OF EXCAVATION —
NOTES AFTER EXCAVATION --
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1111 Carlson Geotechnicai FIGURE 14
v•is � a 7185 SW Sandburg Street,Suite 110
(JOAO Tigard,OR 97223 TEST PIT NUMBER fP-1
Telephone; (503)601-8250
so3 60t azs0 Fax: (503)601-8254
PAGE 1 CF
CLIENT Crescent Grove Cemetery PROJECT NAME Crescent Grove Cemetery Expansion
0 PROJECT NUMBER G0602906 PROJECT LOCATION 9925 S.W.Greenburq Road,Tigard,OR 97223
DATE STARTED 8/25/06 COMPLETED 8/25/06 GROUND ELEVATION TEST PIT SIZE
EXCAVATION CONTRACTOR Client GROUND WATER LEVELS:
iiEXCAVATION METHOD Test Pit AT TIME OF EXCAVATION
LOGGED BY Gabe Burgess CHECKED BY Ryan Houser AT END OF EXCAVATION -
NOTES AFTER EXCAVATION
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