Corporate Headquarters (610) 277-0880 FAX 277-0878 Southern New Jersey (856) 768-1001 FAX 768-1144 Central Pennsylvania (717) 697-5701 FAX 697-5702 Lehigh Valley 149 Main Street Emmaus, PA 18049 (610) 967-4540 FAX 967-4488 [email protected]www.earthengineering.com FOUNDATION REPORT PROPOSED ADDITION FOR UPPER PROVIDENCE TOWNSHIP BUILDING UPPER PROVIDENCE TOWNSHIP, MONTGOMERY COUNTY, PENNSYLVANIA Prepared For: Richard Kapusta & Company 935 Landis Road Telford, Pennsylvania 18969 EEI Project Number: 29307.00 December 12, 2016
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
The material designated as Stratum II is visually described as interbedded weathered
siltstone and sandstone in the form of red brown sandy silt to silty sand. This material was
observed to be encountered in a highly weathered state. The Stratum II material was encountered
at boring locations B-102 and B-103, and extended to depths of 9.0 (B-102) and 11.5 (B-103) feet
below the existing ground surface. The SPT (N) values recorded during the sampling of this
material ranged from 36 to 72 blows on the sampling barrel per foot of penetration. The SPT (N)
results indicate that the Stratum II material is dense to very dense.
STRATUM III
The material designated as Stratum III is visually described as weathered shale in the form
of red brown to gray sand and gravel. The Stratum III material was encountered at each boring
location, which extended to the conclusion of the borings at depths ranging from 10.0 to 15.0 feet
below the existing ground surface. The SPT (N) values recorded during the sampling of this
material ranged from 61 blows on the sampling barrel per foot of penetration to 50 blows with no
penetration. The SPT (N) results indicate that the Stratum III material is very dense.
BEDROCK
Auger refusal was encountered at each boring location at depths ranging from 10.0 to 15.0
feet below the existing ground surface. Auger refusal is typically interpreted as the drilling
apparatus encountering the bedrock surface. The corresponding bedrock elevations can be found
in Table II below:
TABLE II BEDROCK ELEVATIONS
Boring Number Surface Elevation* (Ft.) Depth to Auger Refusal (Ft.) Bedrock Elevation (Ft.)
B-101 310.4 10.0 300.4
B-102 308.7 10.5 298.2
B-103 308.6 15.0 293.6
Note: * The ground surface elevation of each boring was determined by utilizing the existing finished floor elevation of a northern portion of the existing building as a reference datum. Based on the provided plans, the existing finished floor elevation was 313.23 feet.
The natural soils are suitable for support of the proposed structure. However, if soft/loose
natural soils are encountered at the site during construction, foundation preparation measures may
also be necessary at the time of excavation. The soft/loose soils should be evaluated by the on-site
representative of the Geotechnical Engineer of Record. All soft/loose natural soils should be
removed and replaced with structural fill. The over excavation, if required, should be backfilled with
compacted lifts of structural fill, to the originally proposed foundation bottom elevation. The
structural fill should be placed and compacted to ninety eight percent (98%) of the material’s
maximum dry density in accordance with ASTM D698.
EEI recommends supporting the proposed structure utilizing a shallow foundation system,
bearing on the medium dense Stratum I soils and very dense Stratum II weathered rock and/or
properly placed structural fill and possibly Stratum III weathered rock. The following foundation
system and soil bearing capacity recommendations are provided by EEI, in addition to those
discussed above.
1. A foundation system consisting of strip and spread footings along with a
slab-on-grade floor system is recommended for the proposed addition.
2. The base of the strip and spread footings should be situated within the medium dense to very dense natural soils and/or newly placed and compacted structural fill as detailed in the FILL AND COMPACTION section of this Report. FILL material and/or soft/loose natural soils encountered at the footing bottom elevation should be removed and replaced with compacted lifts of structural fill, or lean concrete. Foundations shall not bear on or above existing FILL and/or soft/loose natural soils.
3. Following implementation of the site and foundation preparation recommendations, the foundations can be designed for a maximum allowable bearing capacity of 3,000 pounds per square foot. Regardless of the load criteria, a minimum eighteen inch (18”) wide strip footing and thirty six inch (36”) spread footing should be utilized.
4. Supported on the suitably dense natural soil and/or properly placed structural fill, total settlements are estimated not to exceed 1.0 inch. Differential settlements are estimated not to exceed 0.5 inch. These settlements were calculated using a bearing capacity of 3,000 pounds per square foot along with the provided column and wall loads (110 kips and 6 klf, respectively).
5. The elevation of the base of the new foundations should match the base elevation of the adjacent existing footings. Alternately, foundations bearing at different elevations should be positioned so that the base of the closest points of the adjacent foundation is located a minimum of one horizontal to one vertical (1:1) from each other. Care should be taken not to undermine existing foundations. Should foundations be undermined, underpinning or shoring will be required.
6. The bottom of exterior footings and footings in unheated areas should be placed at least thirty six inches (36”) below the final exterior grade for protection from frost heave.
7. All footing bottoms should be tamped and completely cleaned of loose material or debris immediately prior to the placement of concrete. The foundation must be dry at the time of concrete placement.
8. The actual bearing conditions of the soil at the footing bottom elevations should be confirmed in the field during excavation, by inspection under the supervision of a Professional Engineer qualified in Geotechnical Engineering.
It should be noted that foundation excavation adjacent to the existing building will likely
encounter loose backfill material. Backfill material for exterior foundation walls is often not placed
and compacted under engineering control. Therefore, localized over-excavation adjacent to the
existing building foundation(s) should be anticipated. The extent of the over-excavation should be
field determined at the time of construction by a qualified representative of the Geotechnical
Engineer of Record.
VIII. FLOOR SUPPORT
Floor slabs for the building addition may be supported on approved soils and/or new
engineered fill placed and compacted over approved subgrade soils in accordance with the FILL
AND COMPACTION section of this Report. Due to the soft/loose FILL materials, overexcavation
and replacement is expected to be required for proper support.
Following stabilization, if required, as previously discussed, floor slabs for the proposed
building addition may be designed as a slab-on-grade system with a recommended Modulus of
Subgrade Reaction value of 150 psi/inch. The subgrade should be prepared in accordance with the
procedures described in this Report. In order to reduce capillary rise and damp floor slabs, a
granular subbase is recommended. The granular subbase will also provide uniform support
distribution between the subgrade soils and the base of the concrete slab. It is recommended that a
minimum of six inches (6”) of clean, coarse-graded aggregate (such as PADOT 2B or other
approved materials) be placed and compacted beneath all floor slab areas. The floor slabs should
be suitably reinforced to control shrinkage cracks. Proper joints should be provided at the interface
of the slab(s) and foundation walls so that a small amount of independent movement can occur
Note: * The ground surface elevation of each boring was determined by utilizing the existing finished floor elevation of a northern portion of the existing building as a reference datum. Based on the provided plans, the existing finished floor elevation was 313.23 feet.
Removal of the very dense materials with a standard back-hoe will prove difficult and result
in slow excavation rates. Improved excavation rates, specifically within the very dense portions of
these weathered materials, will be realized utilizing a late model, high power track-mounted hoe in
lieu of a standard backhoe. Removal of the deeper portions of the very dense Stratum II weathered
rock, such as during trench excavation, may require hydraulic hammering, ripping or other rock
removal techniques.
Deeper excavations for utilities may also encounter the bedrock surface. The rock removal
may be aided by the typically closely spaced fractures within the bedrock. However, rock
excavation within confined foundation and utility trenches is expected to require hydraulic
hammering, ripping, or other rock removal techniques. The final determination of the rock removal
method should comply with all Township codes and generally accepted safety guidelines.
The on-site soils will require careful moisture control as they are sensitive to moisture
changes. Materials stockpiled for use as structural fill should be graded to shed water and rolled to
maintain the soils. During periods of wet site conditions, travel upon the building pad and
construction areas should be limited to minimize disturbance of the subgrade which will lead to
instabilities.
Any structural fill imported to the site should meet the following criteria:
Free of organic matter, ash, cinders, frozen materials, and demolition debris.
Plasticity Index less than ten (10). Less than fifteen (15) percent by weight rock fragments larger than
three (3) inches, less than thirty (30) percent by weight larger than ¾ inches, and less than thirty (30) percent by weight smaller than the No. 200 sieve.
Meets the definition of clean fill according to PADEP Management of Fill Policy, Document Number 258-2182-773.
The criteria are provided as a general guideline for soil materials imported to the site. Soil
materials available for use as structural fill should be submitted to the Geotechnical Engineer of
Record for evaluation prior to use at the site.
B. COMPACTION CRITERIA
Structural fill should generally be placed in horizontal lifts not exceeding eight inches (8”) in
loose thickness and compacted with a sheepsfoot or smooth drum vibratory roller with a minimum
static weight of ten (10) tons. Where compaction by hand-operated equipment is necessary,
structural fill should be placed in horizontal lifts of six inches (6”) loose thickness. The optimum lift
thickness and number of repetitions necessary to achieve the required percentage compaction
values should be determined in the field with test passes of the chosen compaction equipment.
The fill material should be placed at its optimum moisture content (+/- 2%) as determined in
accordance with ASTM D698 and compacted to a minimum percentage of the maximum dry density
as indicated in Table IV.
TABLE IV COMPACTION CRITERIA
Fill Area Percent of Maximum Dry Density as
per ASTM Standard D698 Foundation Support and Slab on Grade 98
The lateral earth pressure coefficients that may be used for designing below grade walls and
retaining walls, if necessary, are shown in Table V. Retaining walls that are restrained from
deflection should be designed for the at-rest (Ko) condition. Retaining walls that are free to deflect,
such as landscape walls, should be designed for the active (Ka) condition. Considered somewhat
conservative, the earth pressure data for the on-site materials was determined from the soil
classification testing and visual classification of the soil samples which was compared to generally
accepted and published values for the various properties.
EEI recommends that a drainage system be installed for walls constructed below grade.
The presence of a drainage system will serve to minimize hydrostatic pressures caused by water
trapped against the walls. If adequate drainage is not provided, the walls should be designed to
resist hydrostatic loads. Additionally, consideration should be given to any surcharge loads at the
top of walls.
TABLE V SOIL PROPERTIES FOR THE COMPUTATION OF LATERAL LOADS
FILL &
STRATUM I STRATUM II & STRATUM III
Effective Stress Angle of Friction – φ 28.0º 30.0º
Dry Unit Weight - γd 110.0 pcf 120.0 pcf
Submerged Unit Weight – γw 47.6 pcf 57.6 pcf Rankine Coefficient of Active Earth Pressure - Ka 0.36 0.33 Rankine Coefficient of Passive Earth Pressure - Kp 2.77 3.00 Rankine Coefficient of at Rest Earth Pressure - Ko 0.53 0.50
It should be noted that for the design of an Segmental Retaining Walls (SRW), the National
Concrete Masonry Association (NCMA) suggests that all soil placed within the reinforced zones of
the system have no more than 35% passing the #200 sieve. The soil classification, conducted by
EEI as part of this investigation, indicates that placement of the Stratum I soil in the reinforced zone
of an SRW is not permitted. However, additional testing should be conducted once the reinforced
backfill material is identified, namely a direct shear test (ASTM D3080). The results of this test may
provide more aggressive soil parameters to be used in retaining wall design, which may effectively
Michael J. Carmosky Assistant Director ~ Lehigh Valley Division
Michael O. Meixell, P.E. Director of Engineering ~ Lehigh Valley Division
Paul J. Creneti, P.G. Director ~ Lehigh Valley Division G:\PROJECTS\29000\29307.00 - UP TOWNSHIP BUILDING - LV GEOTECH\REPORT\29307.00 - UPPER PROVIDENCE TWP. BLDG. REPORT.DOC
APPENDIX
PLATE 1 - TOPOGRAPHIC MAP OF SITE
Visit us at http://www.dcnr.state.pa.us
Created using PA DCNR Map Viewer Copyright 2011 Esri. All rights reserved Collegeville Quadrangle Map created on Wed Nov 30 2016
PLATE 2 - BEDROCK GEOLOGY MAP OF SITE
Visit us at http://www.dcnr.state.pa.us
Created using PA DCNR Map Viewer Copyright 2011 Esri. All rights reserved Collegeville Quadrangle Map created on Wed Nov 30 2016
Date:
F.F.E.= Finished Floor Elevation
UPPER PROVIDENCE TOWNSHIP BUILDINGUPPER PROVIDENCE TOWNSHIP, MONTGOMERY COUNTY, PENNSYLVANIA
FILL - Brown to Gray Sandy Silt with Trace Root Fibers
www.earthengineering.com
TOPSOIL
STRATUM III - Red Brown to Gray Sand and Gravel(Weathered Shale)
313.23'
STRATUM II - Red Brown Sandy Silt to Silty Sand(Interbedded Weathered Siltstone and Sandstone)
Lithology Graphics
0.4'
26
12/12/2016
290
305.0+/-
A-102SHEET:
STRATUM I - Red Brown Silt to Sandy Silt
B.C.S.F.E.= Bottom of Crawl Space Footing Elevation
F.F.E.=
B.C.S.F.E.=
308
300
298
296
294
292
290
314
310
306306
304
302
300
298
296
294
292
312
PREPARED FOR
EL
EV
AT
ION
(fe
et)
3.0'10
29307.00
302
BORING PROFILES
304
EARTHENGINEERINGINCORPORATED
Geotechnical Engineers & Geologists
314
312
310
308
Project Number:
61
Auger RefusalHard Augering
11.5'-15.0'
Auger RefusalHard Augering
9.5'-10.5'
B-102EL. 308.7'
10.5'
9.0'
5.0'
0.3'
4
72
6.5'
36
20
211.0'
2.2'
50/0''
60
71
50
B-103EL. 308.6'
15.0'
4.5'
0.4'
21
12
11.5'
Auger RefusalHard Augering
6.5'-10.0'
50/5''
50/5''
B-101EL. 310.4'
10.0'
12.6 Odor:
% Gravel: Coarse: 0.0 Fine: 1.9 Diameter, mm % Finer