12_Supplemental_Utility_Locating_Services.pdf

VIA EMAIL: janis.cooper@cityarchriver.org

March 19, 2014 J017065.14

Ms. Janis Cooper City Arch River 2015 Foundation Gateway Tower, Suite 700 One South Memorial Drive St. Louis, Missouri 63102

Re: Supplemental Utility Locating Services at North Service Center

CAR 2015

Jefferson National Expansion Memorial St. Louis, Missouri

Dear Ms. Cooper:

Geotechnology, Inc. has completed supplemental utility locating services for the Jefferson National Expansion Memorial Project CAR 2015 North Service Center Building located in St. Louis, Missouri. The project was performed in general accordance with original proposal number P017065.09 revised dated December 13, 2013 and the Work Authorization dated February 18, 2014. The project scope was comprised of locating utilities at six locations in the vicinity of the southeast corner of the North Service Center. Utility drawings provided by Michael Van Valkenburgh Associates, Inc.

(MVVA) were reviewed. In general, site utilities included electric and water lines.

Geophysical surveys were performed to locate utilities in the vicinity of the six locations previously staked by the project surveyor, Engineering Design Source, Inc. (EDSI). The surveys were performed on February 25 through February 29, 2014 using a GSSI SIR 3000 ground penetrating radar unit with a 400 MHz antenna, Radiodetection RD-4000 meter, Pipehorn 800 Pipe and Cable locator, and EM31 frequency domain electromagnetic unit. Utilities were marked on site using pin flags.

Vacuum excavations were performed at eight locations. Observations made during excavation activities are summarized in Table 1. Field reports with site sketches are presented in Appendix A and photographs are presented in Appendix B.

Electric lines were observed at six locations. In four of these locations the electric lines were encased within a concrete duct. The depth to the top of the electric lines ranged between approximately 18 inches and 60 inches. Water lines were observed at two location locations and appeared to be constructed of steel or PVC. The depth of the water lines ranged between approximately 34 inches and 46 inches.

Geotechnology’s geophysical crew coordinated with Engineering Design Source, Inc. (EDSI) survey crews who surveyed vacuum excavation locations. Coordinates of vacuum excavation locations, as provided by EDSI, are included in the summary table. Refer to EDSI for the utility location drawing.

TABLE 1

UTILITY LOCATING SERVICES

JEFFERSON NATIONAL EXPANSION MEMORIAL

NORTH SERVICE CENTER

ST. LOUIS, MISSOURI

VACUUM EXCAVATION SUMMARY

J017065.14

Size Type Material Northing Easting Elevation at

Ground Surface (ft-msl)

Depth to Top of Utility

(in)

Elevation at Top of Utility

(ft-msl)

Condition of Utility

PH-1 None Silty Clay NA NA NA 14038596.04 2444255.85 445.60 NA NA NA Utility not observed at this location PH-2 None Silty Clay 2" Electric Plastic 14038577.86 2444257.52 445.57 18 444.07 Good PH-3 None Silty Clay NA NA NA 14038586.21 2444264.02 445.41 NA NA NA Utility not observed at this location

PH-3A None Silty Clay 36" Electric Concrete Duct 14038585.37 2444267.62 445.45 60 440.45 Good PH-4 None Silty Clay 2" Electric Plastic 14038583.45 2444272.95 445.32 24 443.32 Good

PH-4A None Silty Clay 2" Electric Plastic 14038579.07 2444264.94 445.70 20 444.03 Good 2 utilities observed in PH-4A PH-4A None Silty Clay 36" Electric Concrete Duct 14038579.07 2444264.94 445.70 58 440.86 Good 2 utilities observed in PH-4A PH-5 None Silty Clay 2" Water PVC 14038589.34 2444275.38 445.24 34 442.41 Good 2 utilities observed in PH-5 PH-5 None Silty Clay 36" Electric Concrete Duct 14038589.69 2444275.32 445.30 37 442.21 Good 2 utilities observed in PH-5 PH-6 None Silty Clay 6" Water Steel 14038571.50 2444285.33 446.31 46 442.48 Good Electric not observed in this location.

Pavement Thickness/T ype Comments

Test Hole

Utility Information

Soil/Fill Material doc/proj/del/J017065.14 Vac Exc TH Data2.xls

APPENDIX A

FIELD REPORTS

APPENDIX B

EXCAVATION PHOTOGRAPHS

CAR 2015 - Jefferson National Expansion Memorial J017065.14 Utility Locating Services

Photograph 1 - PH-2: View of plastic electric line.

Photograph 2 - PH-3A: View of hole with concrete duct bank exposed.

Photograph 3 - PH-4: View of plastic electric line.

Photograph 4 - PH-4A: View of concrete covering electric line. Plastic electric line is also visible.

Photograph 5 - PH-5: View of PVC water line above concrete duct bank.

Photograph 6 - PH-6: View of steel water line exposed. Electric line was not exposed in this excavation.

APPENDIX C

LIMITATIONS OF REPORT

UTILITY SURVEYING LIMITATIONS

1. This report was prepared for the exclusive use of the owner, architect, and engineer for evaluating the project as it relates to the technical aspects discussed herein. It can be made available to prospective contractors for information on factual data only and not as a warranty of subsurface conditions included in this report. Unless other contractual agreements were made, the services described in this report were carried out in accordance with the Terms for Geotechnology's Services that were attached to the proposal.

2. Geotechnology endeavored to perform the utility surveying in accordance with generally accepted practices of other consultants undertaking similar studies at the same time and in the same geographical area. The findings and conclusions stated herein must be considered not as scientific certainties, but rather as professional opinions concerning the significance of the limited data gathered during the course of the survey. No warranty, express or implied, is made.

3. The geophysical analyses and conclusions contained in this report are based on the site conditions, project layout, grid size, geophysical data, and interpretive procedures described herein and are for preliminary planning purposes only. Geotechnology can make no interpretation as to the presence of underground features at locations beyond the survey lines.

4. The possibility exits that abandoned, forgotten, non-tonable utilities or utilities without a tracer wire, utilities buried excessively deep beyond detection limits of standard geophysical survey methods, or undocumented utilities may be missed using standard utility surveying services. Geophysical exploration methods are non-intrusive, indirect, and potentially influenced by a variety of natural or man-made conditions. The potential for detecting the presence or absence of underground objects or voids is based on the quality of the recorded data as limited by site conditions, and on the interpretation of the data received;

hence, there will always be the potential of not observing a subsurface object or interpreting the presence of a subsurface object where one does not exist.