295 Polson G DGPS.pdf

UNITED STATES COAST GUARD

Delivery Order No. HSCG88-08-J-623223

Site No. 227 Polson 295' Guyed DGPS Antenna

Polson, MT

C O N T E N T S

Page LIST OF PHOTOGRAPHS...................................................................... i

EXECUTIVE SUMMARY

INSPECTION PHOTOS AND NOTES

RECOMMENDED MAINTENANCE

ESTIMATED MAINTENANCE COST

VERTICALITY TABULATION AND PLOTS

GUY TENSION TABULATIONS

TOWER TWIST PLOTS

APPENDIX A:

CHRONOLOGICAL NARRATIVE ............................................................... I

APPENDIX B:

EXCERPTS FROM CG TOWER MANUAL ................................................ II

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LIST OF PHOTOGRAPHS

√ A photo reference is checked if there is a related work item in the

Recommended Maintenance section of the report.

No. Description Page

295' Guyed Tower 1 Overall 2, 3 Overall views of tower base and compound areas 4 √ Base insulator with overspray 5 Overall of tower base area 6 √ Base insulator with overspray, inspectors tightened loose nuts 7 √ Loose leg splice bolt at bottom of Section 1, Leg B 8 Overall view of isolation transformer 9, 10 Inspectors tightened a loose nut at a isolation transformer support arm 11 Typical Face A panel 12 √ Deflected diagonal in Panel 1-9, Face C 13 Typical leg splice in satisfactory condition 14 √ Deflected diagonal in Panel 3-6, Face B 15, 16 Different views of first guy level connections in satisfactory condition 17, 18 Inspectors cleaned and painted corroded areas on the tower legs 19 √ Loose Leg A splice bolt between Section 3 and 4 20 √ Loose Leg C splice bolt between Section 7 and 8 21 Overall of view of top two tower section 22 Top TLE connections in satisfactory condition 23 Overall of top strobe 24 Close up view of top strobe tag 25 View down the tower from the top 26 Typical Anchor A 27 Typical Anchor B 28, 29 Typical light corrosion at structural anchor rods below grade, no action 30, 31 Typical satisfactory condition of TLE anchors 32, 33 Typical light corrosion at TLE anchor rods below grade, no action 34 Wire caught around middle insulator on 4-B2 guy wire 35 Typical good porcelain break up insulator

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21' Reference Masts 36, 37 Different views of the reference masts and equipment shelters 38 Overall of Reference Mast No. 1 39 Overall of Reference Mast No. 2 40 √ Loose splice bolt on Reference Mast No. 1, 11' level 41 √ None of the coax lines were grounded at reference masts 42, 43 √ Plastic ties used to support coax at both reference masts 44, 45 √ Inspectors cleaned and painted corrosion on reference masts, no top caps ...27

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EXECUTIVE SUMMARY

The 295' DGPS antenna in Polson, MT was inspected on 30 April, 1 May, and 4 May 2009 by

Philip Nickels and Jody' O'Neal. The weather was overcast to partly cloudy with temperatures in the 40s°F and winds calm to 5 mph.

The DGPS antenna consists of a 295' Stainless G-25 guyed tower and two 21' self-supporting reference masts. The Stainless tower is guyed in three directions at five levels and in twelve directions at the top. The lacing consists of solid members welded to the tower legs. This tower is an energized tower and sits on top of a base insulator. Downtime is required to climb this tower.

The two 21' reference masts are similar to a Rohn 45G. They each support three antennas.

The GPS coordinates for this site are:

47° - 39.771' N

114° - 6.885' W

STRUCTURAL MEMBERS — The inspectors checked all the leg splice bolts for tightness and documented three loose bolts. Each bolt was painted red for future replacement within one year. Their locations are located in the following table:

Table 1: Leg Splice Bolt Replacement Schedule Location Size Leg Photo No.

Between base insulator and Section 1 1" diameter x 4" A325 B 7

Between Section 3 and 4 1" diameter x 2.25" A325 A 19

Between Section 7 and 8 1" diameter x 2.25" A325 C 20

The inspectors documented two deflected diagonals both of which should be reinforced within one year. Their locations are Panel 1-9, Face C (Photo No. 12) and Panel 3-6, Face B (Photo No.

14).

Site No. 227 Polson

The inspectors measured the coating thickness of the galvanizing throughout the tower. The average thickness per section varied between 7.3 and 13.1 mils. There were a few isolated areas of corrosion that were treated by the inspectors during the course of the inspection (Photos No.

17 and 18). Upon final inspection, the tower was free of corrosion.

BASE INSULATOR — Three of the four bolts securing the base insulator to the concrete pier had loose nuts. The inspectors tightened the loose nuts and ensured the locking nuts were tight as well (Photo No. 6). No further action is required.

There was overspray on the base insulator from previous rust preventive measures at the anchor bolts (Photos No. 4 and 6). Within one year the insulator should be cleaned and paint removed.

OBSTRUCTION MARKING AND LIGHTING — The 295' tower was equipped with one white flashing strobe at the top of the tower. The light fixture was a Flash Technology Electro

Flash FH 308 manufactured in 09-1999. The power to the light is fed through an isolation transformer at the base of the tower. The inspectors tightened an anchor bolt that secures the lower isolation transformer ring support arm to the concrete pier (Photos No. 9 and 10).

The Raytheon technicians reported the strobe had produced alarms in the past however the light appeared to operate correctly during the inspection.

GUY SUBSYSTEM — All guy connection hardware was free of corrosion. The inspectors excavated each anchor rod at least 12" below grade and documented only light cases of corrosion on the rods (Photos No. 28, 29, 32, and 33). No action is required.

GUY TENSIONS AND VERTICALITY — Upon initial inspection most of the wires were within their specified range of ±5% of the design values and the tower was leaning 3" at the fourth guy level. The inspectors adjusted the tensions to bring the tower closer to true vertical and to within the required tension tolerance levels. Upon finial inspection the largest deviation from true vertical was 2.25" at the top of the tower.

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ANTENNA SYSTEM — The inspectors examined all the break up insulators and corona rings with a high power scope. There was one abnormality on the 4-B2 guy wire where there was a piece of wire caught around the middle break up insulator (Photo No. 34). This appeared to be trash that had been discarded from the tower. No action is required at this time.

REFERENCE MASTS — The loose 7/16" bolt at the 10' level splice on Reference Mast #1 should be replace within one year (Photo No. 40). Both masts should be equipped with top caps within the next year (Photos No. 44 and 45). None of the antenna lines were grounded and coax ground kits should be installed within one year (Photo No. 41). The plastic ties supporting the coax lines should be replaced with stainless steel fasteners within one year (Photos No. 42 and

43).

MAINTENANCE ACCOMPLISHED — The inspectors coated isolated areas of corrosion with a cold galvanizing compound in areas throughout the tower (Photos No. 17, 18, 44, and 45).

The inspectors tightened loose anchor bolts at the base insulator and at the isolation transformer support arm (Photos No. 6, 9, and 10).

OSHA STANDARDS — This tower was not equipped with a ladder but it did have horizontal lacing members in the climbing face and a safety cable climb system. The safety climb system was in satisfactory condition.

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Photo No. 1

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Photo No. 2

Photo No. 3

Photos No. 2 and 3 are overall views of the tower base and compound areas.

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Photo No. 4

Photo No. 5

There was overspray on the base insulator from previous rust preventive measures at the anchor bolts (Photo No. 4). Within one year the insulator should be cleaned and the paint removed.

Photo No. 5 is an overall view of the tower base area.

Site No. 227 Polson

Photo No. 6

Photo No. 7

Three of the four bolts securing the base insulator to the concrete pier had loose nuts. The inspectors tightened the loose nuts and ensured the locking nuts were tight as well (Photo No. 6).

No further action is required. The leg splice bolt at the bottom of Section 1 on Leg B was loose and should be replaced within one year (Photo No. 7).

Site No. 227 Polson

Photo No. 8

Photo No. 8 is an overall view of the isolation transformer.

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Photo No. 9

Photo No. 10

The inspectors tightened a loose nut at the isolation transformer support arm anchor (Photos No.

9 and 10).

Site No. 227 Polson

Photo No. 11

Photo No. 12

Photo No. 11 shows a typical panel on Face A. The deflected diagonal in Panel 1-9, Face C should be reinforced within one year (Photo No. 12).

Site No. 227 Polson

Photo No. 13

Photo No. 14

Photo No. 13 shows a typical leg splice in satisfactory condition. The deflected diagonal in Panel 3-6, Face B should be reinforced within one year (Photo No. 14).

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Photo No. 15

Photo No. 16

Photos No. 15 and 16 are different views of the first guy level connections. All guy connections were in satisfactory condition.

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Photo No. 17

Photo No. 18

The inspectors cleaned isolated areas of corrosion and coated those areas with a cold galvanizing compound (Photos No. 17 and 18).

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Photo No. 19

Photo No. 20

The loose bolts that the inspectors painted red at the Section 3-4 Leg A splice (Photo No. 19) and Section 7-8 Leg C splice (Photo No. 20) should be replaced within one year.

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Photo No. 21

Photo No. 22

Photo No. 21 is an overall view of the top two sections of the tower. Photo No. 22 is a closer view of the tower top showing TLE connections in satisfactory condition.

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Photo No. 23

Photo No. 24

Photo No. 23 is an overall view of the top strobe. Photo No. 24 shows a close view of the top strobe tag.

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Photo No. 25

Photo No. 25 is a view down the tower from the top.

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Photo No. 26

Photo No. 27

Photos No. 26 and 27 show the typical construction and condition of the A and B Anchors, respectively.

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Photo No. 28

Photo No. 29

Photos No. 28 and 29 show typical light corrosion at the structural anchor rods below grade. No action is required at this time.

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Photo No. 30

Photo No. 31

Photos No. 30 and 31 show the typical satisfactory condition of the TLE anchors.

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Photo No. 32 Photo No. 33

Photos No. 32 and 33 show the typical condition of light corrosion on the TLE anchor rods below grade. No action is required at this time.

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Photo No. 34

Photo No. 35

The inspectors examined all the break up insulators and corona rings with a high power scope.

There was one abnormality on the 4-B2 guy wire where there was a piece of wire caught around the middle break up insulator (Photo No. 34). This appeared to be trash that had been discarded from the tower. No action is required at this time. Photo No. 35 shows a typical porcelain break up insulator in good condition.

Site No. 227 Polson

Photo No. 36

Photo No. 37

Photos No. 36 and 37 are different views of the reference masts and equipment shelters.

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Photo No. 38 Photo No. 39

Photos No. 38 and 39 are overall views of Reference Mast No.1 and No. 2, respectively.

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Photo No. 40

Photo No. 41

The loose 7/16" bolt at the 10' level splice on Reference Mast #1 should be replaced within one year (Photo No. 40). None of the antenna lines were grounded and coax ground kits should be installed within one year (Photo No. 41).

Site No. 227 Polson

Photo No. 42 Photo No. 43

The plastic ties supporting the coax lines on the reference masts should be replaced with stainless steel fasteners within one year (Photos No. 42 and 43).

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Photo No. 44 Photo No. 45

The inspectors cleaned isolated areas of corrosion on the reference masts (Photo No. 44) and coated the prepped areas with a cold galvanizing compound (Photo No. 45). Neither of the reference masts were equipped with top caps to prevent water from entering the legs (Photos No.

44 and 45). Caps should be installed within one year.

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RECOMMENDED MAINTENANCE

Deficiencies observed on this tower may have an effect on the structural integrity. It is necessary to perform the recommendations outlined below in the suggested time frame to avoid more serious and costly repairs in the future.

WITHIN ONE YEAR:

1) Clean the base insulator and removed the overspray (Photos No. 4 and 6).

2) Replace the leg splice bolts as described in Table No. 1.

3) Reinforce the deflected diagonals in Panel 1-0, Face C and Panel 3-6, Face B (Photos

No. 12 and 14).

4) Replace the 7/16" Rohn splice bolt at the 11' level on Reference Mast No. 1 (Photo No.

40).

5) Install coax ground kits on the antenna lines at both reference masts (Photo No. 41).

Mechanically connect the coax leads to the tower structure.

6) Remove the plastic ties that support the antenna lines on the reference masts and install stainless steel hangers for the ½" lines and support the smaller diameter cables with tape installed using the method described in Appendix B (Photos No. 42 and 43).

7) Install caps at the top of the reference masts to prevent water from entering the 1.5" OD legs (Photos No. 44 and 45).

COST ESTIMATING Sheet 1 of 2

WORKSHEET CONTRACT NUMBER:

HSCG88-08-D-623111

ACTIVITY: LOCATION: TOWER HEIGHT & DESIGNATION:

CEU Oakland Site No. 227 Polson 295' Guyed DGPS Antenna

PROJECT:

ITEM (OR FEATURE) DESCRIPTION NO. OF UNIT UNIT

UNITS UNIT COST COST COST COST

1) Remove the overspray and clean the insulator 4 MH $102.50 $410

Paint remover 1 GAL $15.00 $15

2) Replace leg splice bolts 4 MH $102.50 $410

1" x 4" Galv (A325) bolt, nut, lockwasher 1 EA $13.00 $13

1 x 2 1/4" Galv (A325) bolt, nut, lockwasher 2 EA $11.00 $22

3) Reinforce the deflected diagonals on Face C

Panel 1-10 and Face B Panel 3-6 8 MH $102.50 $820

L 3 x 3 x 1/4 2 EA $95.00 $190

1/2" u-bolt, nuts, lockwashers 4 EA $7.00 $28

4) Replace splice bolt at the 11' level of

Reference Mast No. 1 4 MH $102.50 $410

7/16" Galv Rohn bolt 1 EA $5.00 $5

5) Install coax ground kits at both antenna masts 4 MH $102.50 $410

Universal ground kit 4 EA $35.00 $140

6) Support the coax with SS hangers and tape per USCG specifications 6 MH $102.50 $615

Round member adapter with standoff 2 BOX $45.00 $90

SS hanger 2 BOX $25.00 $50

Electric tape 1 ROLL $10.00 $10

Fillament tape 1 ROLL $15.00 $15

Continued

Project Management

Mobilization

Equipment APPROVED BY: TITLE: DATE: Subtotal

LABOR COST $3,075

Neal Bayless 5-Jul-09 Subtotal

MATERIAL COST $578

Subtotal

COST (EST.) $3,653

Vice President

To Be Completed Within One Year

D13 Tower inspection and Minor Maintenance

DEPARTMENT OF HOMELAND SECURITY

LABOR COSTQUANTITIES MATERIAL COST

COST ESTIMATING Sheet 2 of 2

WORKSHEET CONTRACT NUMBER:

HSCG88-08-D-623111

ACTIVITY: LOCATION: TOWER HEIGHT & DESIGNATION:

CEU Oakland Site No. 227 Polson 295' Guyed DGPS Antenna

PROJECT:

ITEM (OR FEATURE) DESCRIPTION NO. OF UNIT UNIT

UNITS UNIT COST COST COST COST

7) Install leg caps on the reference masts 4 MH $102.50 $410

Leg caps 6 EA $5.00 $30

Project Management $1,000

Mobilization $5,000

Equipment $2,500

APPROVED BY: TITLE: DATE:

LABOR COST $3,485

Neal Bayless 5-Jul-09

MATERIAL COST $608

TOTAL COST (EST.) $12,593

Vice President

DEPARTMENT OF HOMELAND SECURITY

To Be Completed Within One Year (Con't)

D13 Tower inspection and Minor Maintenance

QUANTITIES MATERIAL COST LABOR COST

Drawn By: PEN Sheet No. 31Date: 05-1-09 Delivery Order No: HSCG88-08-J-623223

DHS, UNITED STATES COAST GUARD

CIVIL ENGINEERING UNIT - OAKLAND

OAKLAND, CA

VERTICALITY TABULATIONS

295ʼ DGPS GUYED TOWER

POLSON, MTPO Box 709 Muskogee, Oklahoma 74401 Telephone: (918) 683-8915 Fax: (918) 683-0888

DATE:

TIME:

TEMP:

WIND:

WEATHER:

INSPECTORS:

FINAL READINGS

Elevation Description1 2

DATE:

TIME:

TEMP:

WIND:

WEATHER:

INSPECTORS:

30 APRIL 2009

11:00 AM

38°F 0-5 mph

OVERCAST

P. Nickels

INITIAL READINGS

Elevation Description

Transit Position Deviation (in.)

North

= Transit Position

1 2

Transit Position Deviation (in.)

30 APRIL 2009

12:30 PM

38°F

CALM

PARTLY CLOUDY

P. Nickels

PLOT PLANGUY LEVELS

Drawn By: PEN Sheet No. 32Date: 5-1-09 Delivery Order No: HSCG88-08-J-623223

DHS, UNITED STATES COAST GUARD

CIVIL ENGINEERING UNIT - OAKLAND

OAKLAND, CA

STRUCTURAL GUY TENSION TABULATIONS

295' DGPS GUYED TOWER

POLSON, MT

PO Box 709 Muskogee, Oklahoma 74401 Telephone: (918) 683-8915 Fax: (918) 683-0888

North

DATE:

TIME:

TEMP:

WIND:

WEATHER:

INSPECTORS:

FINAL READINGS

DATE:

TIME:

TEMP:

WIND:

WEATHER:

INSPECTORS:

INITIAL READINGS

30 APRIL 2009

8:00 AM

38°F 0-5 mph

OVERCAST

P. Nickels, J. O’Neal

30 APRIL 2009

11:00 AM

42°F

CALM

OVERCAST

P. Nickels, J. O’Neal

PLOT PLANGUY LEVELS

Drawn By: PEN Sheet No. 33Date: 5-1-09 Delivery Order No: HSCG88-08-J-623223

DHS, UNITED STATES COAST GUARD

CIVIL ENGINEERING UNIT - OAKLAND

OAKLAND, CA

TLE TENSION TABULATIONS

295' DGPS GUYED TOWER

POLSON, MT

PO Box 709 Muskogee, Oklahoma 74401 Telephone: (918) 683-8915 Fax: (918) 683-0888

North

DATE:

TIME:

TEMP:

WIND:

WEATHER:

INSPECTORS:

FINAL READINGS

DATE:

TIME:

TEMP:

WIND:

WEATHER:

INSPECTORS:

INITIAL READINGS

30 APRIL 2009

8:00 AM

38°F 0-5 mph

OVERCAST

PO Box 709 Muskogee, Oklahoma 74401 Telephone: (918) 683-8915 Fax: (918) 683-0888

Level: Twist:

positive values = clockwise twist negative values = counter clockwise twist

Level: Twist:

Level: Twist:

Drawn By: PEN Sheet No. 34

DHS, UNITED STATES COAST GUARD

CIVIL ENGINEERING UNIT - OAKLAND

OAKLAND, CA

TWIST PLOTS

295ʼ DGPS GUYED TOWER

POLSON, MT

= Tower position at specified level

= Tower position at base x y

Twist = = arctan(x/y)

Elevation Description

Elevation (ft.) x (ft.) y (ft.) (°)

Twist Elevation Description

Elevation (ft.) x (ft.) y (ft.) (°)

Twist

Date: 05-4-09 Delivery Order No: HSCG88-08-J-623223

Level: Twist:

Level: Twist:

Level: Twist:

DATE:

TIME:

TEMP:

WIND:

WEATHER:

INSPECTORS:

4 MAY 2009

10:30 am 45°F SW 0-5 mph

PARTLY CLOUDY

Site No. 227 Polson

I

Appendix A: Chronological Narrative

Date: 30 April 2009 Weather Conditions: Overcast, 40-55°F, 0-5 mph winds

Time Work Performed 8:00 am – 3:30 pm Measured and adjusted tensions and verticality. Inspected anchors.

Date: 1 May 2009 Weather Conditions: Partly Cloudy, 48-45°F, calm winds

Time Work Performed 8:00 am – 9:30 am Examined insulators and corona rings. Inspected reference masts.

Date: 4 May 2009 Weather Conditions: Partly Cloudy, 40°F, 0-5 mph

Time Work Performed 8:30 am – 11:30 am Performed climbing inspection.

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II

Appendix B: Excerpts from USCG Tower Manual

9.E.9 - Lighting System Inspection and Maintenance