SOILS FINAL LETTER.pdfLANDAU
14 ASSOCIATES
June 19, 2014
Providence Health & Services
1321 Colby Avenue
Everett, Washington 98201
Attn: Mr. David Wachob
RE: SUMMARY OF CONSTRUCTION OBSERVATIONS
SWEDISH/EDMONDS HOSPITAL PARKING GARAGE STRUCTURE
EDMONDS, WASHINGTON
Dear Mr. Wachob:
Landau Associates provided geotechnical observation, testing, and consultation services during
construction of a parking garage structure at Swedish/Edmonds Hospital in Edmonds, Washington. Our
construction observations and test results are summarized in this letter report. Submission of this letter
report completes our scope of services for this project.
PROJECT BACKGROUND
Providence Health & Services constructed a three-story parking garage structure at the
Swedish/Edmonds Hospital complex in Edmonds, Washington. The new parking garage structure is
located on the west side of the existing Puget Sound Cancer Center Building and on the south side of the
existing Stevens Medical Office Building in an area that was previously occupied by an asphalt -paved
parking lot. The new parking garage structure is supported on shallow foundations. The project also
included the installation of an underground stormwater detention system that was constructed on the east
side of the new parking garage.
Landau Associates previously conducted a geotechnical study at the project site and developed
conclusions and design -level recommendations regarding environmental considerations, site preparation
and earthwork, reuse of onsite soils, wet weather earthwork fill placement and compaction, temporary and
permanent slopes, seismic design, shallow foundation support and settlement, foundation and site
drainage, concrete slabs -on -grade, below -grade retaining walls, dynamic lateral earth pressures, and low
impact development techniques. Results of this study are presented in our November 22, 2013 revised
report titled Report, Geotechnical Engineering Services, Swedish/Edmonds Hospital Parking Garage
Structure, Edmonds, Washington. The recommendations presented in the referenced geotechnical report
were incorporated, as appropriate, into the construction documents, which were prepared by
ENVIRONMENTAL I GEOTECHNICAL I NATURAL RESOURCES
130 2nd Avenue South • Edmonds, WA 98020 • (425) 7780907 • fax (425) 778-6409 • vtivw.Iandauinc.com
SEATTLE ^ SPOKANE ° TACOMA • PORTLAND
JRJ Architects, LLC. The general contractor for the project was Andersen Structures, LLC of Seattle,
Washington.
SCOPE OF SERVICES
Providence Health & Services retained Landau Associates to provide geotechnical observation,
testing, and consultation services during earthwork and foundation -related construction activities for the
project. The focus of our services was to assist Providence Health & Services in determining that critical
earthwork and foundation -related construction activities were accomplished in general accordance with
the project plans and specifications. Our services were provided in general accordance with the scope of
services outlined in our October 18, 2013 proposal. Our scope of services included the following tasks:
® Reviewing the project plans and specifications
® Construction observation related to utility trench backfill and compaction
® Construction observation related to building foundation subgrades
® Construction observation related to slab -on -grade and sidewalk subgrades
® Construction observation related to foundation and detention vault backfill and compaction
® Construction observation and testing related to pavement subgrades
® Performing laboratory testing on structural fill and backfill materials
® Preparing field reports after each site visit
® Preparing this letter report summarizing our conclusions regarding the suitability of the work
completed with regard to the project plans and specifications
® Providing geotechnical consultation related to the tasks outlined above.
OBSERVATION PROCEDURES
Between January 8, 2014 and June 3, 2014, Landau Associates personnel made forty (40) site
visits to observe critical earthwork and foundation -related construction activities associated with
construction of the parking garage structure at Swedish/Edmonds Hospital. As of the date of this letter
report, all critical earthwork and foundation -related construction activities have been completed.
Construction observations were performed on a part-time basis. Site visits were typically coordinated
through Andersen Structures. Earthwork and foundation related construction activities were evaluated
based on qualitative observations and quantitative testing using a nuclear densometer. Qualitative
observations were generally limited to subgrade preparation for building foundations, slabs -on grade, and
pavements using a steel T -probe. Quantitative measurements were obtained on compacted structural fill,
wall backfill, and utility trench backfill using a nuclear densometer.
6/19/14 PA\205\009\Fi1eRm\R\Fina1 Summary Report.doex LANDAU ASSOCIATES
2
Summaries of our observations and test results were provided verbally to the contractor during
each site visit. Copies of our written daily field reports, which document our observations, opinions, test
results, and recommendations of the specific areas observed, were previously transmitted to you
concurrent with the construction progress. In instances where Landau Associates observed conditions not
in conformance with the project plans and specifications, we recommended corrective action appropriate
to the situation, and subsequently verified that corrective measures were carried out.
SUMMARY OF OBSERVATION RELATED TO FOOTING AND SLAB -ON -GRADE SUBGRADES
Landau Associates observed finished subgrades for footings and slabs -on -grade. Specific areas
that were observed included subgrades for the footings and slab -on -grade of the parking garage structure,
detention vault, and sidewalks.
Qualitative measurements were obtained on finished subgrades using a steel probe. In general,
finished subgrades were observed to be firm, dense, and unyielding. In areas where the exposed subgrade
was soft or unstable, unsuitable soils were either removed to an appropriate depth below subgrade
elevations and backfilled with compacted structural fill or recompacted in place. In our opinion, the
subgrade soils observed should provide suitable support for the onsite structures.
SUMMARY OF OBSERVATION RELATED TO PAVEMENT SUBGRADES
Landau Associates observed finished subgrades for pavements. Pavement subgrades were
assessed using a steel T -probe and by observing proof -rolling of the exposed subgrade. Proof -rolling
equipment generally consisted of heavy construction equipment. In general, finished pavement subgrades
were observed to be firm, dense, and unyielding. In areas where the exposed subgrade was soft or
unstable, unsuitable soils were either removed to an appropriate depth below subgrade elevations and
backfilled with compacted structural fill or recompacted in place. In our opinion, the pavement subgrade
soils observed should provide suitable support for the onsite pavements.
SUMMARY OF EARTHWORK RELATED TESTING AND MONITORING
Landau Associates observed backfilling operations on a part-time basis throughout the
construction of the project. Coordination of our site visits was generally through the general contractor
(Andersen Structures). Specific areas observed and tested included backfill placed against footings,
backfill around foundation stem walls, backfill around the detention vault, and utility trench backfill for
onsite utilities.
6/19/14 P:\205\009\Fi1eRm\R\Fina1 Summary Report.docx LANDAU ASSOCIATES
3
Backfill was generally observed to be placed in lifts of appropriate thickness and compacted to a
relatively firm, dense, and unyielding surface. Compaction equipment typically consisted of a smooth -
drum vibratory roller, hoe -pack attached to a mid-sized excavator, or vibratory plate compactor.
Field density tests were performed at locations selected by our field personnel at a frequency
considered to be appropriate to adequately judge whether the earthwork being performed during our site
visits was in substantial conformance with the requirements of the project specifications. The density
tests were performed using a nuclear densometer in general accordance with ASTM International
(ASTM) D2922 test procedures. Our observations and the results of our field density tests indicate that
the structural fill soils were generally compacted to at least 95 percent of their maximum dry density.
Areas of fill that did not initially meet the 95 percent compaction requirement were subsequently
reworked and satisfactorily recompacted.
Based on our representative's observations and compaction test results, it is our professional
opinion that critical earthwork and foundation -related portions of the Swedish/Edmonds Hospital Parking
Garage Structure project were performed in general accordance with the intent of our geotechnical design
report and the project plans and specifications. This conclusion applies only to work performed under the
observation of representatives of Landau Associates between January 8, 20I4 and June 3, 2014. We
cannot provide advice, opinions; or conclusions relative to site work that we did not observe.
Within the limitations of scope, schedule, and budget, our geotechnical observation and testing
services have been provided in a manner consistent with that level of care and skill ordinarily exercised
by members of the profession currently practicing in the same locality under similar conditions as this
project. We make no other warranty, either express or implied. Landau Associates' observation of the
contractor's work does not relieve the contractor of their responsibility to produce a completed project
that conforms to the project plans and specifications.
We appreciate the opportunity to be of service to you on this project. If you have any questions
regarding the content of this letter report, or additional information is required, please contact me.
LANDAU ASSOCIATES, INC.
10 A
Steven R. Wright, P.E.
Principal
SZW,ICTM/rgm
6.19,'14 p4o59oam iteRmiizt al Su msryAtpndDC� t.AN®AuAssoclA`fEs
4