melick-tully - MoreMonmouthMusings

MELICK-TULLY
ANC
ASSOCIATES,
Principals:
P.C.
GEOTECHN ICAL E NGINEERS AND
ENVIRONMENTAL CONSU LTANTS
RAYMOND J . TULLY, P.E
EUGENE M GAllAGHER JR., P.E.
FDBERT E. SCHWANKERT. P.E.
TOCD E. HOROWITZ, P.E.
MARK R. OENNO. P.E.
Senior Associates:
RICHARD 0 . UEV, CPG
STEVEN 0. THORNE, P.E.
JI'.MES H. BEADlE. P.E.
Consultants:
August 12, 2009
THOMAS E. TULLY . P.E
0-!ARLES T. MELICK, P.E
ROBERT J. VAN ORDEN . PE
Borough of Highlands Planning Board
c/o T&M Associates
11 Tindall Road
Middletown, New Jersey 07748
Attention:
Mr. Joseph Venezia, P .E., P .P., C.M.E.
Planning Board Engineer
Re:
Second Geotechnical Review
Proposed Enclave at Mt. Mitchell Subdivision
Block 105.107, Lot 1.1
Borough of Highlands, New Jersey
Highlands Development Group
Introduction
This letter updates our geotechnical review comments relative to the proposed Enclave at
Mt. Mitchell residential project which is proposed · to be constructed by Highlander Development
Group in the Borough of Highlands, New Jersey. The site of the proposed project is located to the
northeast of Ocean Boulevard and New Jersey Route 36, southeast of Scenic Drive, and south of
Bayside Drive.
Discussion
Our preliminary geotechnical review comments were provided in our letter of July 2, 2009.
Subsequent to submission of our comments, our representative met with Maser Consulting (Maser)
Please Reply to:
~NORTHERN NJ OFFICE: 117 Carnl Road. South Bocnd Brook, NJ OBBBO I Phone: (732) 356-3400 Fax: (732) 356-9054
0 SOUTHERN NJ OFFICE: 520 FeHowsl>p Road, Suite 8208, Mount Laurel, NJ OB054 /Phone: 1856) 914-0077 Fax: (856) 914-0078
0 !:DUTHERN NY OFFICE· 324 Route 208. MorToe, NY 10950 I Phone: 1845) 7B3-9190 Fax: (845] 783-5060
Borough of Highlands Planning Board
August 12,2009
Page 2
and T&M Associates (T&M) on July 23, 2009 to discuss their geotechnical-related comments and
concerns. Maser Consulting formally responded to these in their July 30, 2009 submission. After
review of their recent submission, we met with a representative of Maser Consulting on August 11,
2009 to discuss in greater detail selected aspects of the submitted items.
Findings
Based on our July 23, 2009 meeting with the applicant, review of the applicant's July 30,
2009 submission, and subsequent follow-up meeting with the applicant on August 11, 2009, we
provide the following comments to the individual responses of Maser to our prior July 2, 2009
geotechnical-related design concerns/comments.
1)
Comment 1 of the Maser response letter provides the requested soil
parameters that were used by Maser to perform the slope stability analyses in
their prior submissions as requested by Melick-Tully and Associates, P.C.
(MT A). Based on this information, and along with additional background
information provided at our meeting of August 11, it remains our opinion
that the engineering soil parameters utilized in the slope stability evaluations
by Maser are reasonable based on the data provided.
As indicated in their original reports, the modeling by Maser indicates that
the loadings from new construction would not have adverse impacts on the
existing slopes. This is largely a result of the site plans requiring cutting or
very limited grading near the slopes and the performance of deep
excavations from the building area that removes large volumes of soil that
more than offset the weight/loads of the new structures. In some cases, the
analysis indicates loading on the slopes would be reduced and which is
shown as an increase in the factor of safety relative to the Maser slope
stability analyses.
2)
Maser responded to comments 2 and 3 of our prior geotechnical review
letter, which requested additional information as to the potential impacts of
temporary construction impact on the sensitive slopes which are to remain
after construction. Maser also provided a requested Conceptual Construction
Staging Plan (per item 3) to demonstrate that the work would be performed
in a manner so as to minimize its potential impact on the adjacent slopes.
The conceptual construction staging report shows the staging for
construction of the buildings and supporting permanent and temporary
Borough of Highlands Planning Board
August 12, 2009
Page3
structures, assuming Building 1 is built first, to be followed by Building 2
and then by Building 3. The provided information also demonstrated the
feasibility of performing the required construction excavation and installing
the retaining wall systems to be performed \vi.thin the established limits of
disturbance, although fmal wall design plans were not included. The plan
also identifies and requires an 80 foot setback for the passage of heavy
construction equipment from the limits of disturbance which generally
defmes the top of the slope along Bayside Drive. We believe the applicant
has adequately responded to our prior request and we recommend this plan
be made part of any approval. The applicant should be required to adjust or
amend this plan and resubmit it for approval at a later time if there is any
anticipated significant future deviations from the plan, or if any stages of
construction are combined.
3)
See response in Comment 2 above.
4)
Consistent with our prior meeting discussion, Maser has confirmed on behalf
of the applicant that the pavement subgrades and asphalt base course will be
monitored by Maser during construction and any areas repairs would be
made as needed. The need for repair work should be evaluated by Maser
and the work performed under their direction and observed by the Borough
Engineer.
5)
The applicant has provided the requested cut/fill plan requested to aid in the
geotechnical review of the project. The cut/fill plan provided confmns that
most of the site outside the building areas will be generally subjected to
limited cutting, while deep excavations would be required at the individual
building footprints, with maximum reported excavation depths of about 61,
41, and 61 feet at Buildings 1, 2 and 3 respectively.
The only substantial filling operation is shown to be located in the southern
portion of the comer of the site primarily where the grades will be raised up
to about 23 feet and a retaining wall constructed to create a portion of the
new entrance roadway between Building 3 and adjacent stormwater
Detention Basin No. 2. Stability analyses previously provided by Maser
indicate that the filling work and the retaining wall could be designed with
appropriate engineering safety factor.
Maser Consulting has estimated that about 44,800, 25,500 and 43,800 cubic
yards of soil would be removed from the Building 1, 2, and 3 excavations
individually and that the expected soil excess that would require removal
from the site upon completion of the project would be on the order of
134,000 cubic yards.
Borough of Highlands Planning Board
August 12, 2009
Page4
6)
Maser provided additional information on the retaining wall designs and
profiles that were requested by MTA to supplement their original design
infonnation and showed added profiles and potential excavation support
structures in the construction staging report. The submitted information
indicates that retaining and excavation support can be suitably engineered
and designed within the anticipated limits of construction and disturbance
shown on the plans. In the slope east of Building 1, the planned permanent
wall will abut the indicated limit of disturbance, and although no grade
change is shown outside the wall, it should be expected that vegetation
irrunediately adjacent to the wall may be impacted and could require
restoration.
It should be understood that the fmal design of the site retaining wall or
excavation support systems have not been completed, are proposed by Maser
to be provided at a later time, and may be performed by others. If designs
provided by others, Maser should be required to confirm that the
geotechnical design criteria utilized in the wall and excavation support
system designs are consistent with their geotechnical recommendations, as
well as all other elements of the plan including the construction staging
report, etc. The construction staging report and other geotechnical and site
review letters should also be provided to the wall/support system designer, if
different than Maser, so that they can be considered in the design. AU fmal
retaining wall designs should be submitted for review and approval and
should include design calculations and analysis, including global slope
stability analyses.
7)
Maser has indicated the applicant would develop and perform the MTA
recommended construction slope monitoring program and show the
requirement for developing the monitoring plan on the plan notes. No
formal plan was provided. We recommend that a formal, written slope
monitoring program be presented for review and approval prior to the start of
construction, and that the recommended initial predevelopment site
inspection be performed as soon as site conditions allow. We also
recommended that the notes on the plan identify that the site engineer, Maser
Consultants, would be responsible for the slope inspections and monitoring
during construction and that they would provide the results of these
inspections and any recommended remedial work to T &M.
8)
Maser has confirmed that soil liners would be provided with swales and
basins to prevent stormwater from being introduced in the slope. The liner
details and limits should be provided on the plans. The indicated design
permeability of the liner soils is consistent with our meeting discussion.
Monitoring of the liner installation should be provided by a geotechnical
engineer at the time of construction, and formal testing of the gradation,
Borough of Highlands Planning Board
August 12, 2009
Page 5
compaction, and permeability of the liner soils provided at that time. The
test infonnation should be provided in a summary report that confirms that
installation of the liners was performed in accordance with the design plans
and would prevent infiltration of the surface runoff or detained water into the
subsoils.
9)
Maser has agreed to perform the additional building explorations required by
the IBC code prior to fmal design of the building foundation systems. They
did, however, request that the test borings be delayed until after demolition
of the site structures which currently impede access to many of the desired
drilling locations and after preliminary grading is complete so as to allow
excavations in building areas to limit the depths of the explorations. While
we believe that many of the explorations could be delayed until at least the
site clearing operations are performed and drilling areas are accessible, we
believe that at least two deep test borings should be performed prior to
approval in currently accessible areas in the footprint of Building No. 1,
where no current boring explorations are shown and where the deepest cuts
are expected within this building area, as a condition of preliminary
approval. While the boring information that was provided and geologic
review suggest that no significant change in the assumed design conditions
will be revealed by the new borings, and we do not believe that information
will materially change the geotechnical findings provided to date, we believe
the borings should be made a condition of preliminary site approval.
Following completion, the boring data should be provided to MTA and
T&M along with the written confirmation from Maser Consulting that the
design parameters and considerations used in the prior submissions and
analyses remain valid, or if any conditions are modified, the submission
should include a discussion of any impacts on their design assumptions.
l 0)
Maser has submitted the requested geologic profiles of the site which show
the modeled subsurface profile and geologic conditions which was helpful in
review of the slope stability analysis previously provided in the prior
submissions. In our meeting discussions, Maser has identified that the
subsurface layering for Section B-B in the original analysis and on "geologic
profile" they assumed for modeling was purposefully sloped to show the
layer dipping toward the steep slope along Bayside Drive, rather than
assuming more horizontal layering consistent with the geologic literature that
would have resulted in more favorable results to allow for a more
conservative evaluation. Maser has also indicated that they did not identify
any significant discontinuities reflective to prior slump block activity on the
site.
Notwithstanding the above, and in consideration of the Borough' s concerns
relative to the potential for slope problems, we believe an additional deep
Borough of Highlands Planning Board
August 12,2009
Page 6
boring should be perfom1ed in an accessible open area at the top of the slope
between Buildings 1 and 2 and Bayside Drive, and by also incorporating the
information from the two additional recommended borings at Building 1, the
data should be used to further develop the geologic profile and reaffirm the
initial fmdings. Therefore, prior to preliminary approval, we recommend
that the three additional borings be perfom1ed and the test boring data and
updated profiles be provided by Maser along with their confirmation that
there are no material changes in their findings .
Summary
In sununary, it appears that Maser Consulting has responded to MTA's prior comments and
concerns relative to the major geotechnical concerns identified in our preliminary geotechnical
review letter and that the information provided indicates that the site can be developed without
substantial impacts on the existing slopes planned to remain provided appropriate construction
precautions are employed. Additional information as noted in this letter should be provided. Final
design details and plans will need to be submitted for various retaining wall, building foundation
and structural system designs for review and approval prior to the start of construction of the
corresponding aspects of the project.
Please contact us if you have any questions regarding this information.
Respectfully submitted,
Melick~Tully
and Associates, P.C.
Qc~
Robert E. Schwankert, P .E.
Vice President
RES/nac
7093-034 *1
(12 copies submitted)
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