HomeMy WebLinkAboutReport/excavation observation/compaction testing CONSULTANTS
. AMERICAN • ENVIRONMENTAL
•GEOTECHNICAL
� ENGINEERING • FORENISICS
- TESTING� INC,
REPORT OF EXCAVATION OBSERVATION
AND COMPACTION TESTING
PROJECT: ,��cE,�E� 1�PORTED TO:
TRINITY LUTHERAN CHURCH ��� _6 �Q06 �C�TECTS REGO +
BUILDING ADDITIONS YOUNGQUIST, INC.
2060 6TH AVENUE NORTH �AMES SIEELE CONSTR.5217 WAYZATA BOULEVARD
LONG LAKE, MINNESOTA SAINT LOUIS PARK, MN 55416
ATTN: LOREN MORSCHEN
AET JOB NO.: 20-06374
CC: JAMES STEELE CONSTRUC.
DATE: SEPTEMBER 27, 2006 ATTN: TIM SACK
II��OT�u�TCTIf11i�
This report presents the results of soil observations and testing we performed for the referenced
project. Our services were conducted on a will-call basis. The scope of our work was limited to
the following:
. Observing the soils in the bottom of the completed mass excavation for the building
addition.
• Drilling hand auger borings in the bottom of the completed excavation.
• Performing hand cone penetrometer tests in the bottom of the excavation.
• Evaluating the suitability of the exposed soils to support the anticipated fill and building
loadings.
• Conducting compaction tests in fill placed to attain proposed subgrade elevations.
• Summarizing the results of our services in a written report.
Our work on this project was authorized by Loren Morchen of�irchitects Fcego + Youngquist,
1riC., OII �UQllSt La, ��Q�.
This documeM shall no�be reproduced:except in full,without written approval oi Hmerican Engineeriny Testiny,Inc.
;,5C Ciev�ian� �Aver�ue �icrtr��5E. Fau�, 11t1�€ 55�"i4
phcr.� �51-F�S-900? �Tol! Fre� 80a-9.'�-�36��� �=ax 6�i-65�-0�7� �YJW1i'3.8:i1cC3�t@S:.�a7t?:
Ofrices throuchou:rior:da,Niinnesota,Sout�Dakota�:Ulisccnsr
AN AFFIRMATIVE ACTION AND EQUAL OPPORTUNITY ENiPLOYER
• AET 7ob No. 20-06374 - Page 2 of 6
CONCLUSIONS AND REC4MMENDATONS
Based on the results of our observations, hand auger borings, hand cone penetrometer probes and
our review of the available information, it is our judgment the soils exposed in the mass excavation
bottom for the building addition were suitable for support of the fill and structural loadings.
The results of the soil compaction tests taken during filling operations indicate that all final tests
met or exceeded the minimum specified compaction level at the elevations and locations tested.
Test#10 did not meet the specified compaction level with the initial effort. We recommended the
soils in the area of this test be recompacted and retested. The result of this retest(test#13R)met or
exceeded the specified compaction level.
These conclusions are intended as a summary. Read the remainder of the report for additional
details.
DESIGN INFORMATION
We understand or assume that the construction underway will consist of an addition to the northeast
corner of the existing building. We further understand this building will:
� Have two above-grade levels.
• Have a first floor elevation of 1024.0, matching the first floor elevation of the existing
building.
� Be supported by conventional spread footings designed using an allowable soil bearing
pressure no greater than 2500 pounds per square foot (ps fl.
• Have bottom-of-footing elevations at about 1020 for the perimeter footings and 1022 for the
interior footings.
' AET Job No. 20-06374 - Page 3 of 6
• Have overall outside dimensions of 124' by 175'.
• Have reinforced masonry block walls, a structural steel interior frame, supporting a wood
frame roof.
� Have normal tolerance to settlement (up to 'h" differential and 1" total).
� Be constructed according to applicable building code requirements.
Deviations from the above design informarion could necessitate altering our conclusions and
recommendations. Contact us if the information stated is different from the actual project design.
Building addition location and elevation information obtained at the site, and presented in this
report, was referenced to the existing building and the slab at door on the north side of the existing
building. This bench mark was given an elevation of 1024.0. Some locations and elevations were
also provided at the site by the excavator's GPS system.
BACKGROUND INFORMATION
Previously,we conducted a subsurface exploration program at the referenced site. The results were
included in our Report of Geotechnical Exploration and Review(AET Job No.01-02675). Refer to
that report for pertinent background information and for our recommendations to prepare the
building area for structural support.
EXCAVATION OBSERVATIONS
We observed the mass excavation for the building addition during the period from August 24,2006
to September 07, 2006. We were not present at the site on a full-time basis. Our services consisted
of periodic visits to the site, coordinated with James Steele Construction, which allowed us to
observe the mass excavation bottom for the entire building addition. In addition to observing the
- AET Job No. 20-06374 - Page 4 of 6
soils exposed in the excavation, we conducted shallow hand auger borings and hand cone
penetrometer probes in the bottom of the excavation. The soils encountered were classified in
general accordance with ASTM:D2488. Estimates were made of their strength properties based on
their resistance to advancement of the hand auger and from the hand cone penetrometer readings.
The soils were also compared to those described by the preliminary boring logs.
The soils exposed in the base of the excavation were judged to be naturally deposited lean clays and
sandy lean clays, similar to those described in the preliminary report and the associated soil boring
logs. Hand cone penetrometer readings indicated these natural soils should be capable of
supporting unit stresses of at least 2,500 psf. The observed soils were judged suitable for support
of the fill and building loads. The attached Excavation Observations Sketch (Figure 1) illustrates
the extent of the excavation we observed and the approximate elevations of the excavation bottom.
In portions of excavation, existing fill soils and soft clays were observed in the area of an existing
and abandoned septic system. These soils were judged unsuitable for support of the footi.ng, floor
slab and fill loads. We recommended that these soils be removed to expose the underlying naturally
deposited sandy lean clays. These naturally deposited sandy lean clays were judged suitable to
support the fill and structural loads. We visited the site during subsequent trips to observe that the
fill and soft clays in the excavation had been removed. The soils exposed in this excavation were
judged to be naturally deposited sandy lean clays. These natural clays were judged suita.ble to
support the fill and structural loads. The approximate area of this excavation is also identified on
the attached sketch.
Standing water was observed in parts of the excavation due to perched water from the abandoned
septic system and a drainage system from the existing parking lot area. A majority of water was
removed from the bottom of the mass excavation, leaving small amounts (up to 2") of water in
localized areas. Since the fill being used consisted of relatively free-draining sand, it was our
opinior.that this sma.11 amou.nt of standing water should not inhibit compaction efforts.
- AET Job No. 20-06374 - Page 5 of 6
Since portions of the mass excavation terminated below foundation grades, 1:1 oversizing of the
excavation bottoms and subsequent fill system was recommended. Our judgments of the excavation
oversizing were based on the GPS positionina a�d elevation information provided for us in the field
by the excavating subcontractor. Based on the information provided, it appeared that sufficiemt 1:1
lateral oversizing was provided for the majoriry of the mass excavation. Only the footprint of the
addition was corrected adjacent to the existing building. The soils under the northeast corner of the
existing building consisted of darker colored existing fill or topsoil,therefore,the excavation for the
new interior footings and interior column pads adjacent to this area could not be provided with the
recommended 1:1 oversizing. This was discussed with Marv Showers of James Steele Construction
and Loren Morschen of Architects Rego + Youngquist Inc., on September 6, 2006. It was decided
that addition excavation or lowering of the footings would not be needed.
FILL COMPACTION TESTING
During the period from August 28, 2006 to September 7, 2006, we conducted 18 density tests in fill
placed in the building. The density tests were conducted on a will-call basis. The field densiry tests
were compared to the laboratory Standard Proctor maximum drY density(ASTM:D698)to arrive at
a percent compaction level for each test. The test results, which are attached, indicated the
specified compaction level was ultimately met or exceeded at the locations and elevations tested.
The result of test#10 did not meet the specified compaction level with the initial compactive effort.
We recommended the soils in this area be recompacted. A retest (test #13R) was taken after this
corrective effort. The result of this retest achieved the specified compaction level at the location
and elevation tested.
• AET Job No. 20-06374 - Page 6 of 6
CLOSURE
The following sheets are attached and constitute an integral part of this report:
• Excavation Observations Sketch (Figure 1).
• Report of Density Tests.
• Earthwork Quality Control Information.
• Freezing Weather Effects on Building Construction.
To protect the client, the public and American Engineering Testing, Inc., this report (and all
supporting information) is provided for the addressee's own use. No representations are made to
parties other than the addressee.
Our services for this project have been conducted to those standards considered normal for services
of this type at this time and location. Other than this, no warranty, either express or implied, is
intended.
SIGNATURES
Report Prepared By: Report Reviewed By:
American Engineering'I'esting, Inc. American Engineering Testing, Inc.
` �—�� �/'`Z �
, �
Jeffrey J. remin Michael P. McCarthy, PE
En�ineering Assista.nt Principal Engineer/ Division Manager
MN License No. 16688
124'
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AET JOB
;. ' r i� ' ' . ','PROJECT TRINITY LUTHERAN CHURCH BUILDING ADDITION NO.
�: �
� i � � i �� i - 2060 6TH AVENUE NORTH 2p-06374
; � � ;
� �,'. , � � , LONG LAKE MINNESOTA
,, , � � , � DATE
AERICAN' � SUBJECT 9/25/2005
��, _ , , , 3. � : EXCAVATION OBSERVATION SKETCH
IGINEEF�ING D�wrt BY c�cKEn sY PAGE
� :TE�TIf�G, IN�:i SCALE not to scale JJC TqpN( Figure 1
;. . ,
;; : ;i i e
CONSULTANTS
AMERICAN •ENVIRONMENTAL
•GEOTECHNICAL
� ENGINEERING •MATERIALS *
- TESTING� INC� •FORENSICS
REPORT OF DENSITY TESTS
PROJECT: REPORTED TO:
TRII�IITY LUTHERAN CHURCH ARCHITECTS REGO &
BUILDING ADDITIONS YOUNGQUIST, INC.
2060 - 6TH AVENUE NORTH 5217 VJAYZATA BOULEVARD
LONG LAKE, MINNESOTA ST. LOUIS PARK, MN 55416
ATTN: LOREN MORSCHEN
AET JOB NO: 20-06374
CC: JAMES STEELE CONSTRUCTION
DATE: SEPTEMBER 27, 2006 ATTN: TIM SACK
FIELD DENSITY TEST DATA
Test
�P�
Below Dry Moist.
Test Test Existing Density Content Proctor Percent
No. Date Test Location Elevarion Gnde � _�_ No. Compaction Scecs•
1 8/28/06 Building addition backf'ill; 1016 1' 123'h 8.2 1 95'f� 95
40'S &3'E of NW comer of
addition
2 8/28/06 Building addition backfill; 1018 1' 126 11.6 1 97'fz 95
60'S &4'VJ of NW corner of
addition
3 8/28/06 Building addition backfill; 1019 1' 127'h 10.4 1 99 95
55'S &2'E of NW comer of
addition
4 8/28/06 Building addition hackfill; 1022'h 1' 131'/z 8.7 1 102 95
20'S &20'E of NW comer of
addition
5 8/30/06 Building addition backfill; 10211h 1' 117 8.7 2 98 95
70'S &30'E of NW corner of
addition
*;est resul�did not meet project specifications.
This document shall not be reproduced,except in full,without wntlen approvai of American Engineering Testing,Inc.
550 Cfevefand Avenue North•St. PauS, MN 55114
Phone 651-659-9001 •Toll Free 800-972-E364•Pax 651-659-�379•wwvv.amengtest.corr�
Offices throughou?Florida,Minnesota,South Dakota&Wisconsin
AN AFFIRMATIVE ACTION AND EQUAL OPPORTUNITY EMPLOYEP.
- AET Job No. 20-06374 - Page 2 of 3
FIELD DENSITY TEST DATA
Test
Depth
Below Dry Moist.
Test Test Existing Density Content Procwr Perceat
No. Date Test Locarion Elevaaon Grade (pcfl (96) No. Comuaction Suecs•
6 8/30/06 Building addition backfill; 1022 1' 118 7.4 2 99 95
15'S & 10'E of NW comer of
addition
7 8/30/06 Building addition backfill; 1022 1' 117'h 7:1 2 981k 95
40'S& 15'E of NW comer of
addition
g 8/31/06 Building addition backfill; 10221fz 1' 113'k g,g 2 95 95
35'S & 18'W of NE comer of
addition
9 8/31/06 Building addition backfill; 5'S 1021'h 1' 113'fz g.g 2 95 95
&25'W of NE comer of
addition
10 9/1/06 Building addition backfill; 1020'h 1' 112'f� g,3 2 94'h** 95
5'N&20'W of NW comer of
existing building
11 9/1/06 Building addition backfill; 1021 1' 117 5.6 2 98 95
35'N &3'W of NW corner of
existing building
12 9/1/06 Building addition bacl�'�ll; 1022 1' 115'k 10.1 2 97 95
15'S & 10'E of NW comer of
addition
13R 9/1/06 Retest of#10 1020'h 1' 118'h 6.5 2 99�k 95
14 9/6/06 Building addition backfill; 1023 1' 118'h 12.3 2 99'h 95
15'E of NE corner of existing
building
15 9/7/06 Building addition backfill; 1022'h 1' 115'h 10.5 2 97 95
40'S & 12'E of NE comer of
existing building
16 9/7/06 Building addition backfill; 1023 1' 118'fz 14.8 2 991h 95
10'S &40'E of NE comer of
addition
*Test result did not meet project specifications.
' AET Job No. 20-06374 - Page 3 of 3
FIELD DENSITY TEST DATA
Test
�P�
Below Dry Moist.
Test Test Existing Densiry Content Prcetor Percent
No. Date Test Location Elevadon Grade (ncfl (%1 No. Comvacrion Snecs•
17 9/7/06 Building addition backfill; 1021�fz 1' 120'k 10.9 2 101 95
15'N &25'W of NE corner
of existing building
18 9/7/06 Building addition backfill; 1022'fz 1' 119 10.7 2 100 95
20'N&60'W of NE comer
of existing building
Method: Sand Cone(ASTM D1556, AET#20-SOI-1)_ Nuclear(ASTM D2922, AET#20-SOI-2) X
LABORATORY MOISTURE-DENSITY RELATIONS OF SOILS (PROCTOR)
Max.Dry
Gravel Test Opt.Moisdue Density
No. Soil Descriation Content � Method Content % �
1 Silry sand with a little gravel, mosdy medium grained,brown 13 B 9.6 129.0
(SM)
2 Sand with silt and a little gravel, mostly fine grained, brown 8 B 9.6 119.2
Procedure&Method: Standard(ASTM D698, AET#20-SOI-3) X Modified(ASTM D1557, AET#20-SOI-4)_,
To protect the addressee, the public, and ourselves, this report(and all supporting information) is provided for the addressee's
own use. No representarions are made to parties other than the addressee.
Reviewed By:
American Engineering Testing,Inc.
� `
Je ey J. Cremin
Engineering Assistant
*Tesc result did not meet project specii�cadons.
. EARTHWORK QUALITY CONTROL INFORMATION
• EXCAVATION BASE EVALUATION
Judgments of supporting soils aze based on soils exposed, and on local samples of soils retrieved by hand augering and
probing. Because conditions in the subsurface are ludden,it is not possible to fully characterize the subsurface conditions.
Therefore,the client must accept that our judgments are limited to those soils which aze directly observable to us.
As soil conditions may be variable at depth, it is best that excavation base observation be aided by deeper exploratory test
borings(usually done prior to construction).Although these deeper borings may not tota.11y reveal what is in the subsurface,
they greatly reduce the risk of deeper poor soils going undetected.
The presence of�ound water within the excavation can also limit the supporting soil evaluation process.Also, if standing
ground water is present, there is a risk to the client that compressible soils may not be observed and remain beneath the
water during excavation.The compressible materials can become trapped beneath or witbin the subsequendy placed fill.
FILLING
Structural fill placement is commonly monitored by performing local compaction tests, which entails comparing a field
density test to a laboratory Proctor test to arrive at a percent compaction. Density tests of fill only provide the compaction
level of the fill at the location and elevation of the test. As many factors contol compaction, such as fill lift thiclmess,
moisture content, material type and compactive effort, compaction variation within fill can exist which may not be
represented by the tests.Density(compaction)tests are considered representative when used in a conscientious program of
controlled fill placement,where the factors influencing compaction are closely monitored. Conclusions about fill suitability
to support structural loadings from the results of a limited number of compaction tests includes increasa em nt�For this
individual drawing the conclusions has complete knowledge of the aforementioned variables during p
reason,part-time testing on a"will-call or trip"basis includes more risk to the client than"full-time"monitoring/testing.
OVERSIZING
Structural elements also exert loadings laterally; and because of this,the excavation and subsequent fill system needs to be
oversized to accommodate these loadings. The extent of latenl oversizing is normally associated with the movement
sensitivity of the structure and the strengtb/compressibility properties of the soils remaining along the excavation sidewalls.
Oversizing on the order of 1 (horizontal):1 (vertical) is typically provided for foundations in "normal" conditions.
However, oversizing on the order of 1'/z:l or more is usually needed in higlily compressible situations such as swamp
deposits.
AET does not practice in the field of surveying and must rely on location and elevation staldng of proposed construction by
the client or their representative. Our measurements in the field are made in relation to those stakes or other location and
elevation information provided to us.The reliability of AET's opinions, conclusions and recommendations based on those
measurements is dependent on the accuracy of the staking or information provided by the client or their representative.
FREEZING WEATHER
Soils which are allowed to freeze will heave and lose density. Upon thawing,these soils will not regain their full original
strength and density.The extent of heave and density/strength loss depends on the soil type and moisture condition; and is
usually more pronounced in finer gained soils, and particularly silty soils. Foundations, slabs, and other improvements
affected by such frost movements should be protected from frost intrusion during freezing weather. If filling takes place
during freezing weather, all frozen soils, snow and ice should be stripped from all areas to be filled prior to new fill
placement; and the new fill should not be allowed to freeze during or after placement. For this reason, it is usually more
beneficial to perform excavate/refill operations during freezing weather in smaller plan areas where grade can be attained
quickly rather than working larger areas where a large amount of frost stripping may be needed.
STRUCTURAL SUPPORT ON UNCONTROLLED FILL
Risks are associated with supporting structures on fill which has not been placed in a controlled and well documented
manner.Even where existing fill appears to be well compacted(including when soil borings have been performed),hidden
poorer or looser soils can potentially exist below or within the fill;or previous excavation and extension of the compacte�
fill may not have been provided with sufficient oversize in all directions to accommodate the new lateral loadings.Risks
can be reduced by means of increasing th�amount of testi�zg and observations.
AMERICAN�NGINEERING TESTING,INC.
20-E.FLD013(2/O 1;
� FREEZING WEATHER EFFECTS ON BUII.DING CONSTRUCTION
GENERAL
Because water expands upon freezing and soils contain water, soils which are allowed to freeze will heave and lose
density.Upon thawing,these soils will not regain their original strength and density.The extent of heave and densiry/
strength loss depends on the soil type and moisture condition.Heave is greater ia soils with higher percentages of fines
(silts/clays).High silt content soils are most susceptible,due to their high capillary rise potential which can create ice
lenses.Fine grained soils generally heave about 1/4"to 3/8"for each foot of frost penetration.This can translate to 1"
to 2" of total frost heave. This total amount can be significantly greater if ice lensing occurs.
DESIGN CONSIDERATIONS
Clayey and silty soils can be used as perimeter backfill,although the effect of their poor drainage and frost properties
should be considered.Basement azeas will have special drainage and lateral load requirements which are not discussed
here. Frost heave may be critical in doorway azeas. Stoops or sidewalks adjacent to doorways could be designed as
structural slabs supported on frost footings with void spaces below. With this design, movements may then occur
between the structural slab and the adjacent on-grade slabs.Non-frost susceptible sands(with less than 12%passing a
�200 sieve)can be used beloi�such areas.Depending on the function of surrounding areas,the sand layer may need a
thicicness uansition away from the area where movement is critical.With sand placement over slower draining soils,
subsurface drainage would be needed for the sand layer. High density extruded insulation could be used within the
sand to reduce frost penetration, thereby reducing the sand ttuclmess needed.We caution that insulation placed near
the surface can increase the potential for ice glazing of the surface.
The possible effects of adfreezing should be considered if clayey or silty soils are used as backfill. Adfreezing occurs
when backfill adheres to rough surfaced foundation walls and lifts the wall as it freezes and heaves.This occurrence is
most common with masonry block walls,unheated or poorly heated building situations and clay backfill.The potential
is also increased where backfill soils are poorly compacted and become saturated. The risk of adfreezing can be
decreased by placing a low friction separating layer between the wall and backfill.
Adfreezing can occur on exterior piers(such as deck,fence or other similar pier footings),even if a smooth surface is
provided.This is more likely in poor drainage situations where soils become saturated.Additional footing embedment
and/or widened footings below the frost zones(which include tensile reinforcement)can be used to resist uplift forces.
Specific designs would require individual analysis.
CONSTRUCTION CONSIDERATIONS
Foundations,slabs and other improvements which may be affected by frost movements should be insulated from frost
penetration during freezing weather. If filling takes place during freezing weather,
all frozen soils, snow and ice
should be stripped from areas ta be filled prior to new fill placement. The new fill should not be allowed to freeze
during transit,placement or compaction.This should be considered in the project scheduling,budgeting and quantity
estimating.It is usually beneficial to perform cold weather earthwork operations in small azeas where grade can be
attained quickly rather than working larger areas where a greater amount of frost stripping may be needed. If slab
subgrade azeas freeze,we recommend the subgrade be thawed prior to floor slab placement.The frost action may also
require reworking and recompacrion of the thawed subgrade.
O1REP015(02/O1} AMERICAN ENGIlV�ERSNG T�STINC-, Il�IC.