Potawatomi Tower Client: Sturgeon Bay Historical Society

Potawatomi Tower

Client: Sturgeon Bay Historical Society

PREPARED AND PRESENTED BY:

Dan Tingley

PhD | PEng (CA) | MIEAust | CPEng | RPEQ (AU)

10476 Sunnyside Rd. SE

Jefferson, O.R., 97352

503-990-7462

woodrandd.com

Final Inspection and Condition State Report

Ma

rch

7th

, 2

019

Final Inspection and Condition State Report | Potawatomi Tower March 7, 2019

Project No. 9001 Page 2 of 40

ABSTRACT

Wood Research and Development (WRD) was commissioned by the Sturgeon Bay Historical Society

(SBHS) to complete an inspection of the columns of the Potawatomi Tower (PT). The PT is currently

closed to the public pending the outcome of inspection reports from various agencies.

It is the understanding of WRD that the United States Department of Agriculture Forest Products

Laboratory has already performed a cursory inspection of the structure which utilizing a Stress-Wave

Timer testing. However, at the request of the SBHS to provide a second opinion on the PT, WRD carried

out additional Non-destructive Testing (NDT), including Through Compression Wave testing using the

EPHOD® Inspection Methodology (Electronic Pulse Highlight and Outline Diagnostics), to determine

the state of the main timber structural elements (columns) in the PT. The NDT testing was conducted in

typical locations where bore sounding would normally have been performed. However, the NDT testing

matrix at these locations involved many more readings than are typically recovered by bore sounding such

that the accuracy of the condition assessment at these locations was significantly better than that achieved

by bore sounding.

The five main Tower Columns were tested and two of the corner columns were found to be in poor

condition with the bottom 4 feet of the columns in heavily degraded state causing an overall

Condition State Rating (CSR) of 4 for these two columns. The center column is in good condition

with a CSR of 2. The two other corner columns have a CSR of 3. The CSR of 4 for the two corner

columns, southeast and southwest, is primarily governed by isolated areas in the columns that can

easily be restored in situ. These two columns and the short length of heavily decayed wood on the

bottom of both columns is the primary reason for the CSR of 4 for the tower. Recommendations

for repairs were outlined in Section 6.0. The structure should remain closed to the general public

until repairs have been made.



TABLE OF CONTENTS

ABSTRACT ............................................................................................................................................................................ 2

TABLE OF CONTENTS ........................................................................................................................................................... 3

1.0 INTRODUCTION .......................................................................................................................................................... 4

2.0 CURRENT CONDITION STATE RATING ......................................................................................................................... 5

3.0 FINDINGS – VISUAL INSPECTION ................................................................................................................................. 6

3.1 VISUAL INSPECTION – GENERAL............................................................................................................................................. 6 3.2 VISUAL INSPECTION – STAIRS, HANDRAILS AND PLATFORMS ....................................................................................................... 7 3.3 VISUAL INSPECTION – NORTHEAST TOWER LEG ........................................................................................................................ 8 3.4 VISUAL INSPECTION – SOUTHEAST TOWER LEG ........................................................................................................................ 9 3.5 VISUAL INSPECTION – SOUTHWEST TOWER LEG ..................................................................................................................... 10 3.6 VISUAL INSPECTION – NORTHWEST TOWER LEG ..................................................................................................................... 12 3.7 VISUAL INSPECTION – CENTER TOWER LEG ............................................................................................................................ 13

4.0 FINDINGS – STRESS WAVE TIME TESTING ................................................................................................................. 14

4.2 SWT SUMMARY - NORTHEAST TOWER LEG ........................................................................................................................... 15 4.3 SWT SUMMARY - SOUTHEAST TOWER LEG ........................................................................................................................... 16 4.4 SWT SUMMARY - SOUTHWEST TOWER LEG .......................................................................................................................... 17 4.5 SWT SUMMARY - NORTHWEST TOWER LEG .......................................................................................................................... 18 4.6 SWT SUMMARY - CENTER TOWER LEG ................................................................................................................................ 19 4.7 SWT SUMMARY - DRAWING .............................................................................................................................................. 20

5.0 CORE SAMPLE TEST RESULTS ......................................................................................................................................... 23

5.1 TIMBER CORES ................................................................................................................................................................. 23

6.0 RECOMMENDATIONS .................................................................................................................................................. 27

7.0 CONCLUSION ............................................................................................................................................................ 28

APPENDIX .......................................................................................................................................................................... 30

APPENDIX A – SWT SUMMARY DRAWINGS .................................................................................................................................... 31 APPENDIX B – SWT DATA ........................................................................................................................................................... 32



1.0 INTRODUCTION

An inspection of the Potawatomi Tower was completed by Wood Research and Development (WRD)

Level II Certified Inspection Technicians during the week of January 14th, 2019. The objective of the

investigation was to establish the general condition of the primary substructure elements. Visual

inspection and non-destructive testing were used in this investigation. An assortment of instruments were

utilized to complete the non-destructive tests, including; EPHOD™ Stress Wave Technology,

psychrometer, moisture meter, and digital camera. This final inspection report has been prepared by Dan

Tingley Ph.D., P.Eng. (Canada), MIEAust, CPEng, RPEQ, senior engineer and wood technologist for

WRD.

Potawatomi Tower (PT) is a 3-tiered structure standing approximately 75 feet tall located in Potawatomi

State Park near Sturgeon Bay, MI. The Tower is currently closed to the public. The structure is comprised

of four wood pole columns situated at the four corners of a square with a fifth column in the center. Each

column is positioned butt down resting on a concrete foundation with the 4 exterior columns angled toward

the interior of the structure. Several wood shim-like elements positioned at the base of each exterior

column help maintain the inward slant of the columns. They are positioned in between the column element

and the concrete foundation. The grain of these wood elements is parallel to the concrete footing with the

end grain facing outwards. Stairs wrap around the central wood pole column to provide access to three

observation levels. The first level is at approximately 25 feet, the second at 50 feet and the top level at 75

feet. The top observation level is open with handrails and used as a viewing platform. The tower is located

on top of Government Bluff a limestone quarry. It provides excellent views of Potawatomi State Park in

the State of Wisconsin.

The PT has a long history of service to the community. Its construction began with the tower design in

1929 at the beginning of the great depression and was completed in 1931with the help of the Sawyer

Commercial Club when they extended a $500 dollar grant for its construction. Money was hard to come

by in those days and the Tower represented a great way forward for the people in the community as it

provided a way to look out over the beauty of the land beyond all obstacles. To be free, to see, and to

dream. Much the same way as the people of the day gained strength to face the future by seeing how things

would be beyond the days of the great depression! The community and United States persevered, through

world wars, economic booms and busts, through it all the country grew. During all this time the tower also

persevered! It stood the test of time. When steel and concrete towers were falling down and being torn

down and taken out of service the Potawatomi Tower stood! When the experts said that timber towers

don’t last, only steel and concrete ones do, the timber Potawatoni Tower stood and still stands today!

This report contains the findings of WRD Level II Certified Timber Structures Inspection Technicians,

certified laboratory technicians and professional engineers who have worked on this project over a two

month period. The nomenclature used in this report is gathered from the USDA Forest Service. The

columns are labelled with their corresponding cardinal direction: Northwest, Northeast, Southwest,

Southeast, and Center. See the ‘Supplemental Documentation’ file for technical information on

deterioration, fungal decay, non-destructive testing, and methods of preventing decay. In addition, this

supplement document contains papers by Tingley on the difference between bore sounding, global

stiffness inspection methods and an elemental strength NDT equipment system like the EPHOD™ system

used in this inspection, amongst other topics.

Section 6.0 of this report outlines the proposed repair strategies for elements which require remediation.



2.0 CURRENT CONDITION STATE RATING

The Condition State Rating system in Table 2-1 has been developed by Wood Research and Development,

through timber inspection experience, to clearly describe the condition of the elements inspected. While

similar rating systems are found in other inspection manuals, the ratings outlined in this report are more

specific to the element. The definitions of the various Condition State Ratings used in this report are as

follows:

Table 2-1: Condition State Rating Descriptions

Condition

State

Subjective

Rating

Estimated

Remaining Life

Span Descriptions

1 Good 100% 80

Years Like new condition and free of defects.

2 Fair 80% 64

Years

Free of defects affecting structural performance, integrity and durability.

Deterioration of a minor nature in the protective coating and/or parent

material is evident.

3 Poor 30% 24

Years

Defects affecting the durability/serviceability which may require

monitoring and/or remedial action or inspection by a structural engineer.

Component or element shows marked and advancing deterioration

including loss of protective coating and minor loss of section from the

parent material is evident. Intervention is normally required.

4 Very Poor 5% 4 Years

Defects affecting the performance and structural integrity of the structure

which require urgent action as determined by a detailed structural

engineering inspection. Component or element shows advanced

deterioration, loss of section from the parent material, signs of

overstressing or evidence that it is acting differently to its intended design

mode or function.

5 Unsafe 1%

Less

Than

2 Years

Structure should be closed. Structural integrity is severely compromised,

and the structure must be taken out of service until a structural engineer

has inspected the structure and recommended the required remedial

action.

1. Typically a structure may be defined as defective when greater than 25% of principal components are rated as

Condition State 4 in a single abutment, pier or span group.



3.0 FINDINGS – VISUAL INSPECTION

A visual inspection of a timber structure is an essential step in evaluating its condition. The visual data

gathered from the inspection is used to determine structural defects that the non-destructive testing will

not, such as missing or failed elements, cracks and splits, cavities, connection details as well as other vital

information. Gathering this information is critical for completing an inclusive and comprehensive

investigation, which takes into account the surroundings in addition to the main structural elements

3.1 Visual Inspection – General

Figure 3-1: The foundations for the Potawatomi Tower are concrete and appear to be in fair

condition. The Tower consists of five timber legs and is currently closed to the general public.



3.2 Visual Inspection – Stairs, Handrails and Platforms

Figure 3-2: Photographs of the stairs, handrails and platforms revealing signs of heavy wear and

Ultra Violet (UV) deteriorations of the timber components. The timber handrails, along with the

stair and platform planks are sagging due to the moist environment and there are cracks at the ends

of some of the larger horizontal support elements near the nails and fasteners. Most of these

components are past their life expectancy and should be replaced, however they are not considered

primary structural elements nor significant cost maintenance items. Note the use of heavy percent

(over 29%) solids paint on large dimension timbers. Timber with a minimum dimension of greater

than 2 inches shouldn’t be coated and encapsulated with heavy person solids paints containing over

29% solids as these coatings trap moisture in the timbers which leads to decay.



3.3 Visual Inspection – Northeast Tower Leg

Photo 1 Photo 2 Photo 3 Photo 4

Figure 3-3: Photographs of the Northeast Tower Leg, from left to right, around 73 feet, 54 feet, 47 feet and 22 feet up from the

ground. The Tower leg shows signs of shrinkage cracks and UV weathering at most locations and, except for around 45 feet to 46

feet otherwise appears to be in fair condition. At about 54 feet and 22 feet, there are noticeable areas of surface treatment with a

coal tar-like substance; presumably repairs made after outer portions of the column were lost. Such repairs were observed

throughout the entirety of the structure either in large portions of the column, as seen in the above images, or in response to more

localized animal activity. Note the raised surface at the location of the knots which have exposed end grain which is more

weather/UV resistant than tangential grain around them.



3.4 Visual Inspection – Southeast Tower Leg

Photo 1 Photo 2 Photo 3

Figure 3-4: Photographs of the Southeast Tower Leg, from left to right, around 72 feet, 54 feet, and 23 feet up from the ground.

The Tower leg shows also shows signs of shrinkage cracks and UV weathering at most locations and appears to be in fair condition.

The outer most portion of all columns was found to be malleable and easily indented when struck with the hammer from the stress

wave timer. This property can clearly be seen in Photo 2 at an elevation of 47.5 feet, where light scraping revealed a previously

unexposed portion of wood. Photo 1 at an elevation of 72 feet, shows an instance of where the coal tar sealant was applied to a

small cavity presumably from avian activity. Several such cavities were found throughout the structure. Note the nut with

inadequate exposed threads (3 to 5 threads should be exposed in a properly torqued nut and bolt combination) in Photo 3.



3.5 Visual Inspection – Southwest Tower Leg

Photo 1 Photo 2 Photo 3 Photo 4

Figure 3-5: Photographs of the Southwest Tower Leg, from left to right, around 72 feet, 47 feet, 23 feet and 2 feet above the

ground. The Tower leg also shows signs of shrinkage cracks at most locations and appears to be in fair condition. A coal tar

surface treatment applied to cavities can be seen in photo 2 at an elevation of 23 feet. While the base of the Tower leg itself

appeared to be in good condition, the wood shims beneath it were soft to the touch with some apparent degradation. Follow-up

stress wave times and core samples yielded strong evidence for an internal void at the base of the column.



Figure 3-6: Photograph of the Southwest column above the first platform at an approximate elevation of 28 feet. The collar

supporting the tie-rods shows signs of having shifted after the exterior of the column compressed on the southwest side, leaving a

gap on the opposite face. The use of collars for tie rod fixing to the columns is an excellent detail as compared to a through bolt

connection particularly an angled downward through bolt connection. These connections lead to decay from moisture infiltration

into the center of the column.



3.6 Visual Inspection – Northwest Tower Leg

Photo 1 Photo 2

Figure 3-7: Photographs of the Northeast Tower Leg, from left to right, around 54 feet and 2 feet up from the ground. The

Tower leg appears to be in fair condition with some radial shrinkage cracks, as with the rest of the columns, the exterior was

easily malleable as seen in photo 1.



3.7 Visual Inspection – Center Tower Leg

Photo 1 Photo 2

Figure 3-8: Photographs of the Northeast Tower Leg, from left to right, around 75 feet and 60 feet up from the ground. The

Tower leg also appears to be in fair condition. The round column terminates at 50 feet with a square 7 ½ inch by 7 ½ inch

square posting for the remainder of elevation.



4.0 FINDINGS – STRESS WAVE TIME TESTING - EPHOD® SYSTEM

This inspection included the use of non-destructive test equipment identified as EPHOD™ (Electronic

Pulse Highlight and Outline Diagnostic) through compression wave technology. The EPHOD™

Equipment was utilized to complete the through compression stress wave measurements along with other

WRD techniques to locate internal decay in a non-destructive nature.

Stress wave time readings were recorded on all of the accessible main timber structural elements.

Appendix B shows the stress wave time readings for all of the elements tested. When the stress wave time

readings (adjusted against a 300mm gauge length) exceed 700 microseconds (μs) but are below 1000μs

the readings are classified as Yellow and typically indicate the early stages of decay that are significant

enough to reduce structural capacity appreciably. This level of degradation will have begun to affect the

structural attributes of the timber element. These are areas where the element would support its own dead

weight and an unknown live load. Readings which exceed 1000μs are classified as Red and typically

indicate decay has significantly reduced structural properties such that the element in that zone could not

support its own dead weight. Readings in excess of 2200 μs indicate cavities are present and 3200μs values

are typically indicative of severe decay as well as cavities within the member and severely reduced

structural properties such that collapse could occur under the structures own dead weight. Figure 4-1

depicts the drawing key for the SWT scale and provides an illustration on the SWT reading configuration

for elements tested. A clock orientation is used to describe the cross-section orientation of the element for

which the reading was recorded through. For the Potawatomi Tower inspection, 12 always refers to the

northern direction, 3 to the east, 6 to the south, and 9 to the west. As an example, in Figure 4-2, a reading

of 540 μs was recorded at 15 feet at 3/9 o’clock. This refers to the reading on the Northeast Tower leg

which was taken 15 feet above the ground with the stop of the stress wave timer placed on either the

eastern or western face of the column and the hammer striking the opposite side. Figure 4-2 and 4-6

exemplify typical recordings conducted on elements throughout the centre. Figure 4-7 shows the

summary drawings for the typical condition of the timber elements tested.

Figure 4-1: SWT Reading Designations and Results Drawing Key



4.2 SWT Summary - Northeast Tower Leg

Figure 4-2: Example of SWT readings recovered from Northeast Tower Leg. The entire length of the Tower leg was tested

and the overall SWT values were promising. However, many locations are close to the Yellow threshold for SWT Values. The

Tower leg will need to preserved or treated to prevent the leg from deteriorating further. Salt rod diffusers would provide this

level of protection. The salt rod depletes a salt brine that neutralizes the acidic PH wave of the decay causing fungal colony.

Length : 75.00 feet

End 1 Dia. : 17.00 inches


0 1.17 2.58 3.83 6 9 12 15 18 21 22 23 - -

17.0 16.9 16.8 16.6 16.4 16.2 15.9 15.6 15.3 15.0 14.9 14.9 - -

6/12 Adjusted 440 420 401 406 337 365 539 545 549 489 458 - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted 443 - 447 - - - - - - - 522 507 - -

3/9 Adjusted - - - - 405 400 407 540 633 586 459 528 - -

4/10 Adjusted 428 - 356 - - - - - - - 569 549 - -

5/7 Adjusted - - - - - - - - - - - - - -

Length : 75.00 feet



28 31 34 37 40 43 46 47 - - - - - -

14.4 14.1 13.8 13.5 13.3 13.0 12.7 12.6 - - - - - -

6/12 Adjusted 455 506 462 454 490 665 685 - - - - - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted - - - - - - 542 481 - - - - - -

3/9 Adjusted 492 443 532 500 685 550 492 528 - - - - - -

4/10 Adjusted - - - - - - 760 470 - - - - - -

5/7 Adjusted - - - - - - - - - - - - - -

Length : 75.00 feet



54 57 60 63 66 69 72 74 - - - - - -

12.0 11.7 11.4 11.1 10.8 10.6 10.3 10.1 - - - - - -

6/12 Adjusted 947 632 565 423 641 540 481 - - - - - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted - - - - - - 561 - - - - - - -

3/9 Adjusted 655 817 467 628 530 592 609 289 - - - - - -

4/10 Adjusted - - - - - - 490 - - - - - - -

5/7 Adjusted - - - - - - - - - - - - - -

Comments :

Log Member Geometry : Round

Location (feet) :

Diameter (inches) :

Location | Number : Tier 2 Component Number : Northeast Visual Condition

Component : Column Location (Sequence #) :Poor

Type :

Location (feet) :

Diameter (inches) :

Comments :


Type : Log Member Geometry : Round


Location (feet) :

Diameter (inches) :

Comments :






4.3 SWT Summary - Southeast Tower Leg

Figure 4-3: Example of SWT readings recovered from Southeast Tower Leg. The base of the Tower leg has several Red SWT

readings which correspond to small voids that were detected while recovering core samples. There is an approximate 2inch to

3inch void found during the increment bore process. The remaining portion of the Tower leg is scattered with Yellow SWT

readings indicating the condition of the column warrants repair and treatment.

Length : 75.00 feet



0 1.17 2.58 3.83 6 9 12 15 18 21 22 23 24 -

18.0 17.9 17.7 17.6 17.4 17.0 16.7 16.4 16.1 15.8 15.7 15.5 15.4 -

6/12 Adjusted 1347 987 622 485 422 425 504 490 826 688 651 - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted 1071 1223 471 509 432 - - - - - 695 675 475 -

3/9 Adjusted - - - - 313 368 431 589 697 695 586 506 737 -

4/10 Adjusted 420 1494 1304 423 576 - - - - - 468 341 459 -

5/7 Adjusted - - - - - - - - - - - - - -

Length : 75.00 feet



26.5 28 30 31 33 36 39 42 45 46 47.5 - - -

15.2 15.0 14.8 14.7 14.5 14.2 13.8 13.5 13.2 13.1 12.9 - - -

6/12 Adjusted 633 452 438 403 643 814 804 712 521 389 - - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted - - - - - - - - - 569 680 - - -

3/9 Adjusted 602 561 432 483 664 471 346 525 767 622 897 - - -

4/10 Adjusted - - - - - - - - - 417 800 - - -

5/7 Adjusted - - - - - - - - - - - - - -

Length : 75.00 feet



54 57 60 63 66 69 70 71 72 - - - - -

12.2 11.9 11.6 11.3 11.0 10.6 10.5 10.4 10.3 - - - - -

6/12 Adjusted 678 780 576 534 655 476 500 389 - - - - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted - - - - - - - - 621 - - - - -

3/9 Adjusted 413 807 697 487 660 451 457 563 583 - - - - -

4/10 Adjusted - - - - - - - - 471 - - - - -

5/7 Adjusted - - - - - - - - - - - - - -

Location | Number : Tier 1 Component Number : Southeast Visual Condition



Location (feet) :

Diameter (inches) :

Comments :




Location (feet) :

Diameter (inches) :

Comments :




Location (feet) :

Diameter (inches) :

Comments :



4.4 SWT Summary - Southwest Tower Leg

Figure 4-4: Example of SWT readings recorded from Southwest Tower Leg. The base of the Tower leg also has several Red

SWT readings but the values do not suggest there are voids present. The remaining portion of the Tower leg is scattered with

Yellow SWT readings indicating the condition of the pile warrants repair and treatment.

Length : 75.00 feet



0 1.17 2.58 3.83 6 9 12 15 18 21 22 23 - -

18.0 17.9 17.7 17.6 17.4 17.0 16.7 16.4 16.1 15.8 15.7 15.5 - -

6/12 Adjusted 1539 2323 829 480 419 321 665 604 784 477 497 - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted 2366 2791 884 456 404 - - - - - 520 - - -

3/9 Adjusted - - - - 384 380 580 491 622 406 543 464 - -

4/10 Adjusted 1089 681 800 432 487 - - - - - 474 554 - -

5/7 Adjusted - - - - - - - - - - - - - -

Length : 75.00 feet



28 31 34 37 40 43 46 47 - - - - - -

15.0 14.7 14.4 14.1 13.7 13.4 13.1 13.0 - - - - - -

6/12 Adjusted 865 256 531 587 624 527 573 - - - - - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted - - - - - - 629 475 - - - - - -

3/9 Adjusted 954 797 530 708 509 547 648 904 - - - - - -

4/10 Adjusted - - - - - - 543 515 - - - - - -

5/7 Adjusted - - - - - - - - - - - - - -

Length : 75.00 feet



54 57 60 63 66 69 71 72.5 - - - - - -

12.2 11.9 11.6 11.3 11.0 10.6 10.4 10.3 - - - - - -

6/12 Adjusted 377 576 801 655 423 650 569 - - - - - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted - - - - - - 310 - - - - - - -

3/9 Adjusted 975 689 832 537 630 664 473 341 - - - - - -

4/10 Adjusted - - - - - - 464 - - - - - - -

5/7 Adjusted - - - - - - - - - - - - - -

Location | Number : Tier 1 Component Number : Southwest Visual Condition



Location (feet) :

Diameter (inches) :

Comments :




Location (feet) :

Diameter (inches) :

Comments :




Location (feet) :

Diameter (inches) :

Comments :



4.5 SWT Summary - Northwest Tower Leg

Figure 4-5: Example of SWT readings recorded from Northwest Tower Leg. Overall the SWT values were good. However,

many locations are creeping close to the Yellow threshold for SWT Values. The Tower leg will need to preserved or treated to

prevent the leg from deteriorating any more.

Length : 75.00 feet



0 1.42 2.58 3.83 6 9 12 15 18 21 22 23 - -

17.5 17.4 17.2 17.1 16.9 16.6 16.3 16.0 15.7 15.4 15.3 15.2 - -

6/12 Adjusted 559 305 396 437 473 421 417 425 397 533 442 - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted 385 - 390 - - - - - - - 562 585 - -

3/9 Adjusted - - - - 439 436 495 551 600 598 544 703 - -

4/10 Adjusted 311 - 352 - - - - - - - 479 521 - -

5/7 Adjusted - - - - - - - - - - - - - -

Length : 75.00 feet



28 31 34 37 40 43 46 47 - - - - - -

14.7 14.4 14.1 13.8 13.5 13.2 12.9 12.8 - - - - - -

6/12 Adjusted 613 381 482 505 524 472 395 - - - - - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted - - - - - - 621 543 - - - - - -

3/9 Adjusted 622 596 500 450 476 504 540 661 - - - - - -

4/10 Adjusted - - - - - - 512 577 - - - - - -

5/7 Adjusted - - - - - - - - - - - - - -

Length : 75.00 feet



54 57 60 63 66 69 72 - - - - - - -

12.1 11.8 11.5 11.2 10.9 10.6 10.3 - - - - - - -

6/12 Adjusted 632 473 788 414 701 464 482 - - - - - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted - - - - - - - - - - - - - -

3/9 Adjusted 710 713 343 431 455 680 562 - - - - - - -

4/10 Adjusted - - - - - - - - - - - - - -

5/7 Adjusted - - - - - - - - - - - - - -

Location | Number : Tier 1 Component Number : Northwest Visual Condition



Location (feet) :

Diameter (inches) :

Comments :




Location (feet) :

Diameter (inches) :

Comments :




Location (feet) :

Diameter (inches) :

Comments :



4.6 SWT Summary - Center Tower Leg

Figure 4-6: Example of SWT readings recorded from the Center Tower Leg. Overall the Tower leg is fair to good condition.

Length : 51.00 feet



0 1.17 2.58 3.83 5.25 9 12 15 18 21 24 - - -

14.5 14.4 14.3 14.2 14.0 13.7 13.4 13.2 12.9 12.6 12.4 - - -

6/12 Adjusted 396 418 442 535 - 350 341 316 410 454 439 - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted 329 - 514 - - - - - - - - - - -

3/9 Adjusted - - - - 468 368 316 310 366 318 487 - - -

4/10 Adjusted 407 - 457 - - - - - - - - - - -

5/7 Adjusted - - - - - - - - - - - - - -

Length : 51.00 feet



27 30 33 36 39 42 45 50 - - - - - -

12.1 11.9 11.6 11.3 11.1 10.8 10.5 10.1 - - - - - -

6/12 Adjusted 342 492 367 397 399 391 441 359 - - - - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted - - - - - - - 307 - - - - - -

3/9 Adjusted 418 435 367 380 381 317 301 641 - - - - - -

4/10 Adjusted - - - - - - - 487 - - - - - -

5/7 Adjusted - - - - - - - - - - - - - -

Length : 24.00 feet

Height : 7.50 inches

Width : 7.50 inches

51.5 54 57 60 63 66 69 72 75 - - - - -

- - - - -

6/12 Adjusted 410 272 426 432 258 258 555 470 528 - - - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted - - - - - - - - - - - - - -

3/9 Adjusted 456 338 630 645 616 590 394 454 470 - - - - -

4/10 Adjusted - - - - - - - - - - - - - -

5/7 Adjusted - - - - - - - - - - - - - -

1

Comments :

Tier Component Number : Center Visual Condition

Column Location (Sequence #) :

RoundLog Member Geometry :Poor

Location | Number :

Component :

Location | Number : Tier 2 Component Number :

Type :

Location (feet) :

Diameter (inches) :

Center Visual Condition



Location (feet) :

Diameter (inches) :

Comments :

Location | Number : Tier 3 Component Number : Center Visual Condition


Type : Log Member Geometry : Rectangular

Location (feet) :

Comments :



4.7 SWT Summary - Drawing

Figure 4-7: The SWT results for the Potawatomi Tower at the North and South Elevations.



Figure 4-8: North Elevation view of the Potawatomi Tower SWT readings.



Figure 4-9: South Elevation view of the Potawatomi Tower SWT readings.



5.0 CORE SAMPLE TEST RESULTS

5.1 Timber Cores

Core samples were retrieved at six different locations in the timber structure. The samples were returned

to WRD’s International Accreditation Services (IAS) (TL193 and AA644) approved laboratory to be

tested for Moisture Content (MC) and Specific Gravity (SG) utilizing ASTM standard methods. Table 5-

1 below shows the analysis of the samples retrieved. Figure 5-1 shows a series of microscope photos

utilized to identify the species of wood found in the columns.

Table 5-1: Results of Moisture Content and Specific Gravity Testing

Two samples were retrieved from areas deemed through visual and SWT inspection to be in good condition, two

samples from marginal areas, and two from areas deemed to be in poor condition. Analysis of the cores retrieved

Project Number : 9001 Equip ID Cali. Due 217.0° F

Start Date for Tests : Jan/21/2019 121 Aug-19 74.7° F

End Date for Tests : Jan/22/2019 123 Aug-19 34.0%

Recorded by : WTH 21 Aug-19 0.2 in

Jan/21/2019 Jan/21/2019 Jan/22/2019 Jan/22/2019

10:45 14:45 8:30 12:45

Specimen Location SWT Reading IDInitial Weight

(grams)

Initial Length

(inches)

Final Length

(inches)

Weight

(grams)

Weight

(grams)

Weight

(grams)

Final Volume

(in^3)

Calculated

Moisture

Content

Specific

Gravity

Smp.1 Out.1 0.385 1.905 1.901 0.341 0.341 - 0.060 13% 0.35

Smp.1 In. 1 0.525 2.359 2.320 0.463 0.462 - 0.073 14% 0.39

Smp.1 In. 2 0.417 1.986 1.931 0.371 0.370 - 0.061 13% 0.37

Smp.1 Out.2 0.428 2.069 2.008 0.387 0.388 - 0.063 11% 0.37

Smp.2 Out.1 0.897 - - 0.798 0.794 - - 13% -

Smp.2 In. 1 0.326 1.351 1.341 0.291 0.292 - 0.042 12% 0.42

Smp.2 In. 2 0.401 1.620 1.701 0.358 0.358 - 0.053 12% 0.41

Smp.2 Out.2 0.786 2.193 3.009 0.701 0.701 - 0.095 12% 0.45

Smp.3 Out.1 0.215 1.037 1.042 0.194 0.193 - 0.033 11% 0.36

Smp.3 In. 1 0.601 - - 0.525 0.524 - - 15% -

Smp.3 In. 2 0.478 1.722 1.967 0.415 0.414 - 0.062 15% 0.41

Smp.3 Out.2 0.664 1.801 2.441 0.580 0.579 - 0.077 15% 0.46

Smp.4 Out.1 0.358 1.693 1.708 0.327 0.325 - 0.054 10% 0.37

Smp.4 In. 1 0.263 1.190 1.198 0.241 0.241 - 0.038 9% 0.39

Smp.4 In. 2 0.351 1.185 1.477 0.311 0.310 - 0.046 13% 0.41

Smp.4 Out.2 0.565 1.880 2.186 0.508 0.507 - 0.069 11% 0.45

Smp.5 Out.1 0.132 0.694 0.691 0.128 0.120 0.120 0.022 10% 0.34

Smp.5 In. 1 0.292 - - 0.268 0.260 0.258 - 13% -

Smp.5 In. 2 0.188 0.928 0.938 0.176 0.169 0.168 0.029 12% 0.35

Smp.5 Out.2 0.159 0.798 0.848 0.148 0.141 0.141 0.027 13% 0.32

Smp.6 Out.1 0.268 1.292 1.267 0.238 0.238 - 0.040 13% 0.36

Smp.6 In. 1 0.595 2.593 2.600 0.521 0.522 - 0.082 14% 0.39

Smp.6 In. 2 0.212 - - 0.188 0.188 - - 13% -

Smp.6 Out.2 0.548 1.597 2.142 0.477 0.476 - 0.067 15% 0.43

Notes / Comments : Average 13% 0.39

Std. Dev 2% 0.04

Median 13% 0.39

Robust C.O.V 9% 9%

Measurement Method E

Increment Cores Method E

The overall value of the MOISTURE CONTENT was determined to be 13% based on the tests of 24 specimens conducted in accordance with Moisture Content -- ASTM D 4442(Method

B Oven drying secondary). The expanded uncertainty of ±12% is based on a coverage factor of 1.96 (95% confidence) calculated in accordance with the GUM.

-- The yellow fields under 'Increment Cores Method E' contain date and times of readings.

Sample 2 Out 1, Sample 3 In 1, Sample 5 In 1, and Sample 6 In 2 were received as numerous small pieces. SG data from these samples

was not recovered

MOISTURE CONTENT

Relative Humidity (RH) :

Increment Bore Diamter :

SPECIFIC GRAVITYThe overall value of the SPECIFIC GRAVITY was determined to be 0.390 based on the tests of 20 specimens conducted in accordance with Specific Gravity ASTM D 2395(Method E) /

ASTM D 2395 (Method B). The expanded uncertainty of ±0.139 is based on a coverage factor of 1.97 (95% confidence) calculated in accordance with the GUM.

Moisture Content -- ASTM D 4442(Method B Oven drying secondary)

Specific Gravity ASTM D 2395(Method E) / ASTM D 2395 (Method B)

Oven Temperature :

Lab Temperature :

Measuring Equipment

Length measurement WRD#

Weight measurement WRD #:

Temperature measurement WRD #:

NE Pile 6' @6-12

Center Pile 15' @3-9

4158

2226

1182

1107

462

340

SW Pile 1'-2"@2-8

SE Pile 1'-2"@4-10

SW Pile 2'-7"@4-10

SE Pile 18' @6-12



aligns with the visual and SWT inspections, areas determined to be in poor condition are truly in poor condition and

areas determined to be in fair to good condition are in fair to good condition. Analysis of the cores also revealed the

Specific Gravity (ratio of density of wood to the density of water, unit less value) of the samples is close to, and slightly

greater than, the Specific Gravity (SG) expected in western red cedar (0.33). While retrieving the core samples of the

Southern columns, a 2.5 inch void was detected in the Southeast column, and a 3.0 inch void was detected in the

Southwest column. Each of these regions allowed the increment borer to slide easily, without effort through the center

of the column for the stated distances. This data, in conjunction with the Specific Gravity measurements and stress

wave times, show that the annulus of the wood surrounding the void has not decayed while the center of the columns

has decayed. Figure 5-1 shows a typical summary Form for one of the core samples. The SWT data correlated well

with the SWT values. The balance of the core data can be found in Appendix C.

The structure core samples revealed moisture contents (MC) that were generally higher inside than outside which is

typical in outdoor timber structures. Typically timber structures have an average MC value of 14.2% when under

closed decks or awnings and 16. 4% when open to the weather. The average value of the moisture content found

matched similar findings for outdoor structures at 13%. Wood begins to decay at MC values over 22%, oxygen over

21% and temperatures between 40 and 120 F. Thus, localized areas in the timber elements in the tower will proceed

to decay when these conditions are present and if anyone of these environmental conditions are not present the wood

will not decay. Clearly there are areas in the tower related to such moisture generating features as metal fasteners and

proximity to concrete that have decayed. These areas that have exhibited reduced SG due to decay are in suspension

and not decaying when the MC values are below 22%. Wood is hygroscopic meaning that it breathes in and out

moisture and equibulates with the surroundings. Thus, as Relative Humidity (RH) and temperature change around the

wood structure the wood MC values change. It is the areas around fasteners, adjacent concrete (concrete holds

moisture at levels that will lead to decay in wood thus the bases should have malthoid barriers between the wood shims

creating tower leg angles and the concrete base pads) and other moisture accumulation areas that decay will proceed

due to localized increases in MC. Metal fasteners condensate daily (dew point) with temperature change and this

condensation fuels higher MC values in and around these fasteners and thus there is more decay found in the wood

around metal fasteners typically. This is particularly true of vertical fasteners that originate from the top faces of timber

connection systems. In such cases these metal fasteners not only lead to condensation that creates elevated MC in the

local wood zones but also allows ambient water to gain access to the inner zones of the timber elements where

evaporation does not occur as fast as outside zones and subsequent higher MC values will lead to accelerated decay

in and around metal fasteners. The use of salt rods in and around metal fasteners will help extend life in the timber by

neutralizing the PH wave.

The use of metal fasteners that are not galvanized or are not manufactured using stainless steel will lead to ferric

degradation. This is the case with the old metal fasteners found in the tower. Ferric degradation is the black/grey

staining found in the wood around raw rusting steel fasteners. This ferric degradation is caused by ferric ions

embrittling the lignin in the wood. This leads to a shrinkage of the wood around the metal fastener shanks and

subsequent loosened joints and in the case of vertical fasteners the allowance of more ambient moisture to the center

regions of the wood elements and subsequent accelerated decay. There is no such thing as dry rot. Dry rot is an

oxymoron, it is impossible to have decay without adequate moisture content in wood.

The outside annulus of the Western Red Cedar columns were found to have better SG values than the center zones of

the columns. This characteristic has been caused by the zone of the column that has a MC value high enough to allow

decay to proceed. Typically around a cavity in wood the SG loss due to decay is adequate to lead to loses in bending

strength, horizontal shear and compression perpendicular to grain of 65 to 80% up to 6 inches away from the cavity.



The radius of reduced strength around extensive decay cavities or zones in timber is generally determined by the

location of treatment zones or zones of reduced MC. In the tower columns the outer zones of wood in the columns are

evaporating water and thus the MC value is lower outside (witnessed in the core samples) than inside. The sound

annulus thickness is determined by the MC gradient from outside to inside the column. The point at which the MC

value exceeds 22% MC working from outside towards the inside is the point at which decay will stop. This

characteristic is also present around condensating metal fasteners. Alternatively the point at which the wood has some

sort of adequate treatment will be the point at which decay is no longer function.



Figure 5-1: Core sample identification microscope photos. Additional photos can be found in

the Appendix



6.0 RECOMMENDATIONS

The tower can be repaired in-kind or with fiber reinforcement and epoxies. The in-kind repair option will

be more involved and will require the tower to temporarily shored when removing and replacing sections

of the tower legs. The fiber reinforcement repair can be completed without shoring the tower. The scope

of the inspection did not cover the platforms and the stairs. These elements should be inspected more

closely to determine which elements should be replaced. However, replacement of stair treads and landing

floor boards and support elements is not a major structural works and would not justify the removal of the

whole tower. In addition steel fasteners that are heavily rusted should be replaced and the wood shims at

the bottom of each column that are forming the angle of the column should be replaced with non-organic

material that does not condensate or decay and acts as not only and angle shim but a moisture damp

proofing agent to prevent moisture from gaining access to the column bottoms, eg. Neoprene with

durometer of 70 or more.

The following charts summarize the restoration work, separated into in-kind and fiber reinforcement

categories, for PT.

Table 6-1: In-kind Repair

Element Location on Element Repair Description

Northeast Tower Leg Entire Length Diffuse with Borate Salt Rods

Southeast Tower Leg Bottom 4 feet Post the Tower leg

Southeast Tower Leg Entire Length Diffuse with Borate Salt Rods

Southwest Tower Leg Bottom 4 feet Post the Tower leg

Southwest Tower Leg Entire Length Diffuse with Borate Salt Rods

Northwest Tower Leg Entire Length Diffuse with Borate Salt Rods

Center Tower Leg Entire Length Diffuse with Borate Salt Rods

Four Main Corner Columns Column Segments with SWT

readings over 800 μs

Segment Post with Fixed End

Moment Connection

Table 6-2: Advanced Fiber Reinforcement Repair Methods

Element Location on Element Repair DescriTowerion

Northeast Tower Leg Entire Length Diffuse with Borate Salt Rods

Southeast Tower Leg Bottom 4 feet Wrap Tower leg with

highstrength fiber

Southeast Tower Leg Entire Length Diffuse with Borate Salt Rods

Southwest Tower Leg Bottom 4 feet Wrap Tower leg with

highstrength fiber

Southwest Tower Leg Entire Length Diffuse with Borate Salt Rods

Northwest Tower Leg Entire Length Diffuse with Borate Salt Rods

Center Tower Leg Entire Length Diffuse with Borate Salt Rods

Four Main Corner Columns Column Segments with SWT

readings over μs

Wrap Column Segments with

High Strength Fiber Wraps



7.0 CONCLUSION

Wood Research and Development was commissioned by the Sturgeon Bay Historical Society to complete

a Condition Assessment of the Potawatomi Tower. The Tower is currently closed to the general public.

The five main Tower Columns were tested and two of the corner columns were found to be in poor

condition with the bottom 4 feet of the columns in heavily degraded state causing an overall

Condition State Rating (CSR) of 4 for these two columns. The center column is in good condition

with a CSR of 2. The two other corner columns have a CSR of 3. The CSR of 4 for the two corner

columns, southeast and southwest, is primarily governed by isolated areas in the columns that can

easily be restored in situ. These two columns and the short length of heavily decayed wood on the

bottom of both columns is the primary reason for the CSR of 4 for the tower. Recommendations

for repairs were outlined in Section 6.0. The structure should remain closed to the general public

until repairs have been made.

Preventative maintenance for the existing timber structure, such as the elimination of vertical connectors

and diffusing of all timber elements will extend the life of the bridge to 50 years, and maintain the Overall

Condition State Rating to 2 based on the following assumptions:

a) Overall Condition State Rating 1 – 100% Remaining Life (80 years)

b) Overall Condition State Rating 2 – 80% Remaining Life (64 years)

c) Overall Condition State Rating 3 – 30% Remaining Life (24 years)

d) Overall Condition State Rating 4 – 5% Remaining Life (4 years)

e) Overall Condition State Rating 5 – 1% Remaining Life (< 2 years)

The maintenance items listed above can be completed at a significant cost savings compared to allowing

the structure to deteriorate and then installing a replacement or alternatively having to demolish it. The

maintenance items for the structure can be completed while the Tower is still erect with minimal site

disturbance. In addition to the cost savings, using advanced timber restoration techniques to repair a

structure in-situ also has the following benefits over new construction;

Reduced site disturbance and excavation work

Reduced potential for erosion or vegetation damage.

Preserves a landmark for the community.

Extends the life of existing assets and utilizes these assets more effectively.

Finally, it is highly recommended that all structural elements be diffused with borate salt rods to prevent

further deterioration during any decision making process as to the future life of the structure. All exposed

bright wood should be treated with Copper Naphthenate and seal end-grain with a paraffin wax sealant in

order to prevent further damage from decay.

In summary the Potawatomi Tower has stood the test of time for nearly 90 years. It has weathered and

contains conventional UV section loss as well as non-structural cracks and splits in some elements. The

tower has two columns with advanced decay and cavities in the bottom four feet. However, well over 80%

of the structure is capable of continuing on in its service to the community with the help of remedial

treatments that can be implemented as the tower stands. It has served the community for decades and

deserves the opportunity to continue to do so. The cost of remedial work is a fraction of the cost of



replacement. The cost of tearing down and disposing of the tower will be of the same magnitude as

repairing the worst of the heavily degraded zones. The best option working forward is to restore the tower

and extend its life utilizing advanced strategies. Clearly, advanced non-destructive testing and assay

sample testing by an IAS certified test laboratory has shown that the vast majority of the primary structural

elements are in a condition suitable for continued service. Proper maintenance will extend life. The

implementation of proper repairs will bring the structure back to proper occupancy capacity. With these

actions the Potawatomi Tower can go on to serve the community for another 90 years.

Dan Tingley Ph.D., P. Eng. (Canada), MIEAust, CPEng, RPEQ

Senior Wood Technology/ Structural Engineer

Wood Research and Development



APPENDIX

Appendix A – SWT Summary Drawings

Appendix B – SWT Data

Appendix C – Core Data



Appendix A – SWT Summary Drawings



Appendix B – SWT Data

Color GA Length

Length : 51.00 feet



0 1.17 2.58 3.83 5.25 9 12 15 18 21 24 - - -

14.5 14.4 14.3 14.2 14.0 13.7 13.4 13.2 12.9 12.6 12.4 - - -

6/12 Adjusted 396 418 442 535 - 350 341 316 410 454 439 - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted 329 - 514 - - - - - - - - - - -

3/9 Adjusted - - - - 468 368 316 310 366 318 487 - - -

4/10 Adjusted 407 - 457 - - - - - - - - - - -

5/7 Adjusted - - - - - - - - - - - - - -

Length : 51.00 feet



27 30 33 36 39 42 45 50 - - - - - -

12.1 11.9 11.6 11.3 11.1 10.8 10.5 10.1 - - - - - -

6/12 Adjusted 342 492 367 397 399 391 441 359 - - - - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted - - - - - - - 307 - - - - - -

3/9 Adjusted 418 435 367 380 381 317 301 641 - - - - - -

4/10 Adjusted - - - - - - - 487 - - - - - -

5/7 Adjusted - - - - - - - - - - - - - -

Length : 24.00 feet

Height : 7.50 inches

Width : 7.50 inches

51.5 54 57 60 63 66 69 72 75 - - - - -

- - - - -

6/12 Adjusted 410 272 426 432 258 258 555 470 528 - - - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted - - - - - - - - - - - - - -

3/9 Adjusted 456 338 630 645 616 590 394 454 470 - - - - -

4/10 Adjusted - - - - - - - - - - - - - -

5/7 Adjusted - - - - - - - - - - - - - -

Length : 75.00 feet



0 1.42 2.58 3.83 6 9 12 15 18 21 22 23 - -

17.5 17.4 17.2 17.1 16.9 16.6 16.3 16.0 15.7 15.4 15.3 15.2 - -

6/12 Adjusted 559 305 396 437 473 421 417 425 397 533 442 - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted 385 - 390 - - - - - - - 562 585 - -

3/9 Adjusted - - - - 439 436 495 551 600 598 544 703 - -

4/10 Adjusted 311 - 352 - - - - - - - 479 521 - -

5/7 Adjusted - - - - - - - - - - - - - -

Location (feet) :

Diameter (inches) :

Comments :

Visual Condition



Location | Number : Tier 1 Component Number : Northwest

Location (feet) :

Comments :

3 Component Number : Center Visual Condition


Type : Log Member Geometry : Rectangular

Location | Number : Tier

Location (feet) :

Diameter (inches) :

Comments :

Center Visual Condition



Location | Number : Tier 2 Component Number :

Type :

Location (feet) :

Diameter (inches) :

SWT Chart - Color Code Key

Sturgeon Bay, Wisconsin Description

Clock Direction :

12 inUS Units

Jan/14/2019 - Jan/16/2019

Adjusted SWT Data

YELLOW

Structure Name :Location (City, St./Prov.) :

Location (Country) :

RoundLog Member Geometry :

SWT values over 1000 - Immediate restoration or replacment

SWT values between 700 and 999 - Elements require caution in use and

Frequent Inspection12 in

Unit of Measure :

Date(s) of Inspection :

12 = North

United StatesRED

Poor

Location | Number :

Component :

1

Comments :

Tier Component Number : Center Visual Condition

Column Location (Sequence #) :



Length : 75.00 feet



28 31 34 37 40 43 46 47 - - - - - -

14.7 14.4 14.1 13.8 13.5 13.2 12.9 12.8 - - - - - -

6/12 Adjusted 613 381 482 505 524 472 395 - - - - - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted - - - - - - 621 543 - - - - - -

3/9 Adjusted 622 596 500 450 476 504 540 661 - - - - - -

4/10 Adjusted - - - - - - 512 577 - - - - - -

5/7 Adjusted - - - - - - - - - - - - - -

Length : 75.00 feet



54 57 60 63 66 69 72 - - - - - - -

12.1 11.8 11.5 11.2 10.9 10.6 10.3 - - - - - - -

6/12 Adjusted 632 473 788 414 701 464 482 - - - - - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted - - - - - - - - - - - - - -

3/9 Adjusted 710 713 343 431 455 680 562 - - - - - - -

4/10 Adjusted - - - - - - - - - - - - - -

5/7 Adjusted - - - - - - - - - - - - - -

Length : 75.00 feet



0 1.17 2.58 3.83 6 9 12 15 18 21 22 23 - -

17.0 16.9 16.8 16.6 16.4 16.2 15.9 15.6 15.3 15.0 14.9 14.9 - -

6/12 Adjusted 440 420 401 406 337 365 539 545 549 489 458 - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted 443 - 447 - - - - - - - 522 507 - -

3/9 Adjusted - - - - 405 400 407 540 633 586 459 528 - -

4/10 Adjusted 428 - 356 - - - - - - - 569 549 - -

5/7 Adjusted - - - - - - - - - - - - - -

Length : 75.00 feet



28 31 34 37 40 43 46 47 - - - - - -

14.4 14.1 13.8 13.5 13.3 13.0 12.7 12.6 - - - - - -

6/12 Adjusted 455 506 462 454 490 665 685 - - - - - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted - - - - - - 542 481 - - - - - -

3/9 Adjusted 492 443 532 500 685 550 492 528 - - - - - -

4/10 Adjusted - - - - - - 760 470 - - - - - -

5/7 Adjusted - - - - - - - - - - - - - -

Length : 75.00 feet



54 57 60 63 66 69 72 74 - - - - - -

12.0 11.7 11.4 11.1 10.8 10.6 10.3 10.1 - - - - - -

6/12 Adjusted 947 632 565 423 641 540 481 - - - - - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted - - - - - - 561 - - - - - - -

3/9 Adjusted 655 817 467 628 530 592 609 289 - - - - - -

4/10 Adjusted - - - - - - 490 - - - - - - -

5/7 Adjusted - - - - - - - - - - - - - -

Comments :


Location (feet) :

Diameter (inches) :



Type :

Comments :


Location (feet) :

Diameter (inches) :



Type :

Location (feet) :

Diameter (inches) :

Comments :




Location (feet) :

Diameter (inches) :

Comments :




Location (feet) :

Diameter (inches) :

Comments :






Length : 75.00 feet



0 1.17 2.58 3.83 6 9 12 15 18 21 22 23 - -

18.0 17.9 17.7 17.6 17.4 17.0 16.7 16.4 16.1 15.8 15.7 15.5 - -

6/12 Adjusted 1539 2323 829 480 419 321 665 604 784 477 497 - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted 2366 2791 884 456 404 - - - - - 520 - - -

3/9 Adjusted - - - - 384 380 580 491 622 406 543 464 - -

4/10 Adjusted 1089 681 800 432 487 - - - - - 474 554 - -

5/7 Adjusted - - - - - - - - - - - - - -

Length : 75.00 feet



28 31 34 37 40 43 46 47 - - - - - -

15.0 14.7 14.4 14.1 13.7 13.4 13.1 13.0 - - - - - -

6/12 Adjusted 865 256 531 587 624 527 573 - - - - - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted - - - - - - 629 475 - - - - - -

3/9 Adjusted 954 797 530 708 509 547 648 904 - - - - - -

4/10 Adjusted - - - - - - 543 515 - - - - - -

5/7 Adjusted - - - - - - - - - - - - - -

Length : 75.00 feet



54 57 60 63 66 69 71 72.5 - - - - - -

12.2 11.9 11.6 11.3 11.0 10.6 10.4 10.3 - - - - - -

6/12 Adjusted 377 576 801 655 423 650 569 - - - - - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted - - - - - - 310 - - - - - - -

3/9 Adjusted 975 689 832 537 630 664 473 341 - - - - - -

4/10 Adjusted - - - - - - 464 - - - - - - -

5/7 Adjusted - - - - - - - - - - - - - -

Length : 75.00 feet



0 1.17 2.58 3.83 6 9 12 15 18 21 22 23 24 -

18.0 17.9 17.7 17.6 17.4 17.0 16.7 16.4 16.1 15.8 15.7 15.5 15.4 -

6/12 Adjusted 1347 987 622 485 422 425 504 490 826 688 651 - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted 1071 1223 471 509 432 - - - - - 695 675 475 -

3/9 Adjusted - - - - 313 368 431 589 697 695 586 506 737 -

4/10 Adjusted 420 1494 1304 423 576 - - - - - 468 341 459 -

5/7 Adjusted - - - - - - - - - - - - - -

Length : 75.00 feet



26.5 28 30 31 33 36 39 42 45 46 47.5 - - -

15.2 15.0 14.8 14.7 14.5 14.2 13.8 13.5 13.2 13.1 12.9 - - -

6/12 Adjusted 633 452 438 403 643 814 804 712 521 389 - - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted - - - - - - - - - 569 680 - - -

3/9 Adjusted 602 561 432 483 664 471 346 525 767 622 897 - - -

4/10 Adjusted - - - - - - - - - 417 800 - - -

5/7 Adjusted - - - - - - - - - - - - - -

Comments :


Location (feet) :

Diameter (inches) :



Type :

Location (feet) :

Diameter (inches) :

Comments :




Location (feet) :

Diameter (inches) :

Comments :




Location (feet) :

Diameter (inches) :

Comments :




Location (feet) :

Diameter (inches) :

Comments :






Length : 75.00 feet



54 57 60 63 66 69 70 71 72 - - - - -

12.2 11.9 11.6 11.3 11.0 10.6 10.5 10.4 10.3 - - - - -

6/12 Adjusted 678 780 576 534 655 476 500 389 - - - - - -

1/11 Adjusted - - - - - - - - - - - - - -

2/8 Adjusted - - - - - - - - 621 - - - - -

3/9 Adjusted 413 807 697 487 660 451 457 563 583 - - - - -

4/10 Adjusted - - - - - - - - 471 - - - - -

5/7 Adjusted - - - - - - - - - - - - - -

Location (feet) :

Diameter (inches) :

Comments :








Appendix C – Core Test Data Results

Date :

Analyzed by : W. Harding D. Tingley

Thuja plicataScientific Name :

Species Identification Results

Project Name :

Project Number :

Specimen Number :

Specimen Location : Center Pile

Potawatomi Tower

9001

1

Common Name : Western Red Cedar

Figure C: Tangential View | Tangential sections yield a lack of longitudinal

parenchyma in the early wood. Parenchyma cells, if they are present, are normally sparse or absent in early wood portions of Western

Red Cedar

Figure D: Radial View | Radial sections illustrate taxodioid cross-field pits which help

to positively identify the species as Wester Red Cedar.

Figure A: Transverse View 1 | An abrupt transition from early wood to late wood along with the noticable lack of resin canals as seen

from the transverse section supports the identification as a variety of Cedar

Figure B: Transverse View 2 | A higher magnification transverse section highlights

the abrupt late wood to early wood transistion as well as the medium texture of

the sample

Figure A: Specimen 1|Western Red Cedar sample exhibited gross features typical of the species, including a cedar odor and reddish-

brown coloration



Date :




Project Name :

Project Number :

Specimen Number :

Specimen Location : Northeast Column

Potawatomi Tower

9001

2

Feb/21/2019


Figure C: Radial View | Inspection of ray cells in show that rays consist of ray parenchyma

without ray tracheids

Figure D: Radial View | Rows of 1 to 2 bordered pits on radial walls of longitduinal

parenchyma in conjuction with the other minute features positively identify the

species as Western Red Cedar

Figure A: Transverse View | Transverse sections show a

lack of longitudinal and horizontal resin canals

Figure B: Tangential View 1 | Tangential sections show

sparse or absent parenchyma cells

Figure A: Specimen 2|Retrieved core sample 2

from the Northeast Column



Date :




Project Name :

Project Number :

Specimen Number :

Specimen Location : Southeast Column

Potawatomi Tower

9001

3 & 5

Feb/21/2019




Figure D: Radial View | Rows of 1 to 2 bordered pits on radial walls of

longitduinal parenchyma in conjuction with the other minute features positively identify the species as Western Red Cedar



Figure B: Tangential View 1 | Tangential sections show absent parenchyma cells

Figure A: Specimen 3 & 5|



Date :




Project Name :

Project Number :

Specimen Number :

Specimen Location : Southwest Column

Potawatomi Tower

9001

4 & 6

Feb/21/2019




Figure D: Radial View | Rows of 1 to 2 bordered pits on radial walls of

longitduinal parenchyma in conjuction with the other minute features positively identify the species as Western Red Cedar



Figure B: Tangential View 1 | Tangential sections show absent parenchyma cells

Figure A: Specimen 4 & 6|

Documents

Potawatomi Tower Client: Sturgeon Bay Historical Society