Amendment 0003_Appendix C - Geotechnical Report.pdf

J.R. Holzmacher P.E., LLC 3555 Veterans Memorial Highway, Suite A, Ronkonkoma, New York 11779-7636

Tel: (631) 234-2220 Fax: (631) 234-2221 e-mail: info@holzmacher.com

The Third Generation of Excellence

In Water Supply, Water Resources, Civil and Environmental Engineering

May 25, 2017

Land, Air, Water Environmental Services, Inc.

Attn: John Lamprecht 32 Chichester Avenue Center Moriches, NY 11934

Re: Geotechnical Evaluation Ocean Beach Pump Station No. 5 503 Bayberry Walk Ocean Beach, NY 11770

Dear Mr. Lamprecht:

J.R. Holzmacher P.E., LLC (JRH) Consulting Engineers has prepared this Geotechnical Evaluation Report (GER) for the above referenced site. We understand that a new well pump house elevated above the Base Flood Elevation with a 10,000 gallon tank below. The soil borings described in this report were completed by Land, Air, Water Environmental Services, Inc. (LAWES). Field data was used in rendering geotechnical evaluation and judgment regarding subsoil suitability in connection with construction at the above referenced site. No materials testing laboratory analysis was requested or performed on any of the soil samples.

EXPLORATION PROGRAM

Soil borings were completed on April 26, 2017 to determine the nature and condition of the soils below the existing ground surface at the site. (1) soil boring was requested to a depth of 50-feet below grade, however, due to the high groundwater encountered the boring began to heave, and was terminated at a depth of 27-feet as the driller was not able to go any deeper, we therefore performed another boring as shown in the attached boring location map to a depth of 22-feet below grade.

The soil borings were completed by LAWES, a NYSDEC licensed driller with oversight by JRH personnel. Samples were collected by a Geoprobe 77DT using a split-spoon core barrel sampler.

The sampler was driven in six-inch increments by using the equivalent force of a 140-pound hammer from a height of thirty inches. Samples were collected using a standard 2” by 24” long split spoon sampler driven into the soil. The driller who recorded the Standard Penetration Test (SPT) values characterized the samples recorded during the performance of the test. Based on these descriptions and measurements, geologic soil-boring logs were prepared.

The general subsurface conditions encountered during the field exploration program are shown in the soil boring logs (Appendix A). Soil stratification is based on the examination of recovered soil samples and interpretation of the field boring logs. The stratification lines, dimensions, as

Geotechnical Evaluation Report Ocean Beach Pump Station No. 5 503 Bayberry Walk, Ocean Beach, NY 11770 May 25, 2017 Page | 2

The Third Generation of Excellence In Water Supply, Water Resources, Civil and Environmental Engineering well as reported values of this report represent the approximate boundaries between the soil types, while the actual transitions and dimensions may be more gradual. While the borings are representative of the subsurface conditions at their respective location and within respective vertical reaches, variations over the site may be encountered.

METHODOLGY

The scope of the work was to drill through unconsolidated soils with a Geoprobe at two (2) boring locations to obtain geotechnical information. Samples were logged and collected at various depths. The borings were logged with respect to blow counts and classified according to the unified soils classification system (USCS). The borings and all sampling was performed in accordance to ASTM D1586-84. Restoration consisted of backfilling the boring hole with sand.

Representative samples were routinely obtained during the drilling process at selected intervals by applying a two-inch diameter split spoon-sampling tube. The sampler was driven by the 30-inch fall of a 140-pound hammer. The number of blows required to drive the sample spoon from 6 inches to 18 inches represents the standard penetration resistance (N), and is an indicator of the safe bearing capacity of the soil.

The drilling and testing procedures were performed applying the guidelines and procedures of ASTM designations:

ASTM D1586 Penetration Test and Split Barrel Sampling of Soils.

ASTM D2488 Recommended Practice for Description of Soils.

ASTM D2487 Standard Practice for Classification of Soils (USCS).

Sectional linear samples were also secured in conjunction with the performance of the standard penetration and density test. The soil profiles reported by the boring logs should be reviewed for specific information at the individual boring location and test depths.

SUMMARY

This report was developed from conventional and standard soil testing procedures and engineering analysis. Fine brown sand, trace gravel, and crushed concrete was recovered from grade to 2-feet below grade at boring location B-1. Fine to coarse brown sand, topsoil, and trace gravel was recovered from grade to 2-feet below grade at boring location B-2. Sand was recovered from 15-feet to 27-feet below grade at boring location B-1 and from 15-feet to 17-feet below grade at boring location B-2. Fine to medium sand, coarse to medium sand and gravel was recovered at the remaining depths of both borings. Low blow counts (N<15) were encountered from grade to 10-feet below grade at boring location B-1 and from grade to 8-feet below grade at boring location B-2.

503 Bayberry Walk, Ocean Beach, NY 11770 May 25, 2017 Page | 3

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SUBSURFACE WATER CONDITIONS

Groundwater was encountered at 1’-0” below grade for both boring locations during the field investigation.

Fluctuation in subsurface water level should be expected throughout the year due to seasonal variations and weather events, tidal variations and other factors that may vary from the time the boring was completed.

FLOOD ZONE

The proposed building site is located in Zone “AE”, an area inundated by 100 year flooding where base flood elevations is 7 feet, as per the Flood Insurance Rate Map (FIRM map), which is included within this report.

OBSERVATIONS AND ANALYSIS

Soil bearing capacity is estimated from results of in-situ tests using empirical correlation factors.

Soil bearing values (SBVs) in tons per square foot (TSF) to undisturbed, structurally rated soils are inferred from blow counts as tabulated in Appendix B.

Boring No. TSF @ 3.5-ft TSF @ 5.5-ft TSF @ 7.5-ft TSF @ 9.5-ft

B-1 0.20 0.25 0.05 0.50

B-2 0.25 0.10 0.15 0.80

The SBVs are predicted based on saturated sands. An additional contingency to address the variation in soil strength can be realized by increasing the reinforcing steel within footings or the pile cap to accommodate “soft spots” without cracking. Lower settlement of the granular materials encountered is expected to be small in magnitude and to occur rapidly as the load is applied. Longer-term settlement of silt and organic layers, if any exist, may be significant.

SEISMIC COMPONENT

The 2015 IBC contains a requirement that every structure be designed to resist the effect of earthquake motion and be assigned a seismic Design Category. The 2015 IBC, Earthquake loads Section 1613.3.2, Site Class Definition further dictates, at a minimum, that Site Class E be imposed. The USGS seismic summary report is included in Appendix C.

Subject Site

Site Designation Class ‘E’

Site Coefficient Fa = 2.5

One Second Site Coefficient Fv = 3.5

503 Bayberry Walk, Ocean Beach, NY 11770 May 25, 2017 Page | 4

The Third Generation of Excellence In Water Supply, Water Resources, Civil and Environmental Engineering

5% Peak Dampened Acceleration Stress Design SDS = 0.304g

One Second Peak 5% Dampened Acceleration Stress Design SD1 = 0.137g

Moreover, the project location would result in a wind design component that would exceed the anticipated effect of seismic action and would therefore govern the structural integrity of the design. The analysis and recommendations are based on the data obtained from the limited test borings performed for this report. The nature and extent of variations may not become evident until open excavation is initiated. Variations should be noted and their impact evaluated with respect to the necessity to modify the recommendations of this report.

LATERAL EARTH PRESSURES COEFFICIENTS

Lateral Earth Pressures as described by theories presented by both Coulomb and Rankine, requires that the foundation size be determined prior to determining the true failure planes and the resultant forces. Since the soils noted in the boring are granular, we recommend that the Active and Passive Lateral Earth Pressure coefficients be based upon cohesionless soils. The angle of internal friction is estimated at 34°, accounting for the variations within the soil column, and can be used in the computation of the loads on the foundation. An internal angle of friction for the soil yields an active earth pressure of Ka = 0.2827 and a passive earth pressure of Kp =

3.5371. Furthermore, the 2015 IBC Table 1806.2 permits an allowable lateral bearing of 150 psf/ft. below natural grade and a 0.25 coefficient of friction lateral sliding resistance for soil types SW, SP, SM, SC, GM, and GC. This would therefore be applicable to the soils found onsite.

RECOMMENDATIONS

The boring exploration was completed to determine the structural design requirements for a structure to be elevated above the base flood elevation with a 10,000 gallon tank located below the elevated structure. The field exploration revealed subsurface conditions having relatively weak bearing capacities from grade to 10-feet below grade at boring location B-1 and from grade to 8-feet below grade at boring location B-2 and extremely high groundwater conditions.

Furthermore, it appears that the proposed 1 story structure will need to be constructed several feet higher in accordance with the FEMA flood zone requirements for this area.

Due to the weak unconsolidated soils, high groundwater encountered, and the elevated first floor of the proposed structure, we recommend the use of drive-cast displacement piles as manufactured by Hubbell or approved equal. We recommend a maximum vertical design capacity of 20 tons (40 tons ultimate). We recommend a 3 1/2 - inch diameter, schedule 80 pile and would recommend a minimum installation depth of 30 feet below grade. The grout mix selected should be engineered for installation in the high groundwater condition, this can be provided by the manufacturer. Once the displacement pile rises above grade it may be necessary

503 Bayberry Walk, Ocean Beach, NY 11770 May 25, 2017 Page | 5

The Third Generation of Excellence In Water Supply, Water Resources, Civil and Environmental Engineering to utilize a sonotube with steel reinforcement around the pile within the grout column to create the required lateral resistance. The grout column is continuous from the pile tip to the top of the pile. Lateral loading for each displacement pile shall not exceed 10 kips.

Timber piles may also be considered, however, vibrations during installation may be a concern for the adjacent structures and should be monitored closely throughout installation. Additionally, it may be difficult to access this location with the equipment necessary to install a 40 ton (ultimate/installation load) timber pile. A timber pile with a 12” butt, and 10” tip is recommended for this capacity and the soils present on site. The bearing capacity values for all sampled depths are available in Appendix B.

The analysis and recommendations are based on the data obtained from the borings completed for this report. The nature and extent of variations may not become evident until open excavation is initiated. Variations should be noted and their impact evaluated with respect to the necessity to modify the recommendations of this report.

Any and all excavations should follow OSHA guidelines for excavation protection. Any excavations that are adjacent to existing buildings should be reviewed with specific interest in the depths of the existing foundations to determine if underpinning would be required. It is further recommended that existing condition surveys of the nearby buildings be conducted to mitigate potential claims of damage, especially if timber piles are selected for the foundation design.

LIMITATIONS

The recommendations in this report are based on our experience and training, in conjunction with the limited soils exposed at the site. We believe that this information gives an acceptable degree of reliability for anticipating behavior of the proposed improvement to be constructed;

however, our recommendations are professional opinions and cannot assure accuracy beyond the limits of the soil profiles from which data was obtained. This report is based on the evaluation at the described site and on the specific anticipated construction.

Very truly yours, Michael C. Simon, P.E.

Principal

MCS:jp Encl.

P:\2017\LAWES\17-08 - Ocean Beach Well Station NO.5 Pump House\Task 1 - Geotechnical Oversight and Evaluation Report\Report\Ocean Beach Pump Station No. 5 Report.doc

The Third Generation of Excellence

In Water Supply, Water Resources, Civil and Environmental Engineering

FIGURE

FIRM MAP

APPENDIX A

SOIL BORING LOGS

Page# 1 of 1

DATE:

SITE: Ocean Beach Pump Station 5 CONSULTANT: de Bruin Engineering , P.C.

503 Bayberry Walk, Ocean Beach, NY Bethpage, NY

27 foot

TIME WATER WAS TAKEN:

AUTOMATIC SPT DROP HAMMER

Geoprobe 77DT DRILLING METHOD: 3.5" Geoprobe rods

HELPER:

0 ft 2 ft

2 ft 4 ft

4 ft 6 ft

6 ft 8 ft

8 ft 10 ft

10 ft 15 ft

15 ft 17 ft

17 ft 20 ft

20 ft 22 ft

22 ft 25 ft

25 ft 27 ft

Land, Air, Water Environmental Services, Inc.

DRILLER'S LOGS

BORING#: B-1

April 26, 2017

DEPTH DRILLED: feet DEPTH TO WATER: 1 CORING DEVICE: 2" x 24" 12:00 PM

WELL/BORING GROUTED : NO

DRILL RIG / GEOPROBE TYPE:

DRILLER: S. Pedersen C. Pedersen

DEPTH

FROM TO RECOVERY

BLOWS / 6

INCHES SAMPLE DESCRIPTION

15 inches 12-3-2-2 Brown/light brown sand, fine, trace of gravel, (SW), wet at

1', piece of crushed concrete at top of spoon

13 inches 2-2-2-3 Light brown/tan sand, coarse to fine, trace of gravel, (SW), wet

12 inches 2-3-2-3 Light brown/tan sand, coarse to medium, trace of gravel, (SW), wet

7 inches 1-PUSH-1-1 Tan sand, coarse to medium to fine, trace of gravel, (SW), wet

13 inches 3-3-7-8 Tan sand, coarse to medium, 20% gravel, (SW), wet

Direct Push Rod Advancement

16 inches 8-15-23-21 Light grey sand, fine to medium, (SW), wet

Direct Push Rod Advancement

11 inches 14-18-22-23 Slight grey/tan sand, medium to fine, (SW), wet

Direct Push Rod Advancement

14 inches 9-15-17-20 Light grey/tan sand, medium to fine, (SW), wet, refusal

The boring / well has been finished at grade as contracted. It is the responsibility of the client and / or property owner to maintain the boring / well and have it legally abandoned when decommissioning is required.

Page# 1 of 1

DATE:

SITE: Ocean Beach Pump Station 5 CONSULTANT: de Bruin Engineering , P.C.

503 Bayberry Walk, Ocean Beach, NY Bethpage, NY

22 foot

TIME WATER WAS TAKEN:

AUTOMATIC SPT DROP HAMMER

Geoprobe 77DT DRILLING METHOD: 3.5" Geoprobe rods

HELPER:

0 ft 2 ft

2 ft 4 ft

4 ft 6 ft

6 ft 8 ft

8 ft 10 ft

10 ft 15 ft

15 ft 17 ft

17 ft 20 ft

20 ft 22 ft

CORING DEVICE: 2" x 24" 2:20 PM

Land, Air, Water Environmental Services, Inc.

DRILLER'S LOGS

BORING#: B-2

April 26, 2017

DEPTH DRILLED: feet DEPTH TO WATER: 1

WELL/BORING GROUTED : NO

DRILL RIG / GEOPROBE TYPE:

DRILLER: S. Pedersen C. Pedersen

DEPTH

FROM TO RECOVERY

BLOWS / 6

INCHES SAMPLE DESCRIPTION

16 inches 1-1-2-2 Light brown/dark brown sand, coarse to fine, trace of gravel, (SW), wet, top 6" topsoil

17 inches 2-2-3-4 Tan/light brown sand, coarse to medium, trace of gravel, (SW), wet

3 inches 1-1-1-1 Light brown/tan sand, coarse to medium, trace of gravel, (SW), wet

18 inches 1-1-2-3 Tan sand, coarse to medium, trace of gravel, (SW), wet

14 inches 5-8-8-9 Tan sand, coarse to medium, 20% gravel, (SW), wet

Direct Push Rod Advancement

18 inches 10-14-23-27 Slight grey sand, coarse to fine, (SW), wet

Direct Push Rod Advancement

15 inches 26-23-24-21 Slight grey sand, fine to medium, (SW), wet, some brown laminations, refusal

The boring / well has been finished at grade as contracted. It is the responsibility of the client and / or property owner to maintain the boring / well and have it legally abandoned when decommissioning is required.

APPENDIX B

SOIL BEARING STRENGTH

Boring Performed April 26, 2017

B-1

Blows N Bearing

From To (per 6") Strength (TSF)

0 2 12 DTW

3 1'-0"

2 5 0.25

2 4 2

2 4 0.20

4 6 2

2 5 0.25

6 8 1

PUSH

1 1 0.05

8 10 3 7 10 0.50

15 17 8 23 38 1.89

20 22 14 22 40 1.99

25 27 9 17 32 1.59

DTW - DEPTH TO WATER

APPENDIX B

Land, Air, Water, Environmental Services (LAWES)

503 Bayberry Walk Ocean Beach, NY 11770

Sample Depth (ft bg)

Ocean Beach Pump Station 5

Consulting Engineers

Boring Performed April 26, 2017

B-2

Blows N Bearing

From To (per 6") Strength (TSF)

0 2 1 DTW

1 1'-0"

2 3 0.15

2 4 2

3 5 0.25

4 6 1

1 2 0.10

6 8 1

2 3 0.15

8 10 5 8 16 0.80

15 17 10 23 37 1.84

20 22 26 24 47 2.34

DTW - DEPTH TO WATER

APPENDIX B

Land, Air, Water, Environmental Services (LAWES)

Ocean Beach Pump Station 5 503 Bayberry Walk

Ocean Beach, NY 11770

Sample Depth (ft bg)

Consulting Engineers

APPENDIX C

USGS SEISMIC SUMMARY REPORT

Design Maps Summary Report

Building Code Reference Document

Site Coordinates

Site Soil Classification

Risk Category

Design Maps Summary Report User–Specified Input

2012/2015 International Building Code (which utilizes USGS hazard data available in 2008)

40.64743°N, 73.15587°W

Site Class E – “Soft Clay Soil”

I/II/III

USGS–Provided Output

SS = 0.182 g SMS = 0.455 g SDS = 0.304 g

S1 = 0.059 g SM1 = 0.205 g SD1 = 0.137 g

For information on how the SS and S1 values above have been calculated from probabilistic (risk-targeted) and deterministic ground motions in the direction of maximum horizontal response, please return to the application and select the “2009 NEHRP” building code reference document.

Although this information is a product of the U.S. Geological Survey, we provide no warranty, expressed or implied, as to the accuracy of the data contained therein. This tool is not a substitute for technical subject-matter knowledge.