5.2 HPSR 07-16-2015 Jackson Street Water Tower
City of Elk River
Condition Assessment
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Prepared By
COLLABORATIVE DesignGroup,inc.
100 PORTLAND AVENUE SOUTH, SUITE 100
MINNEAPOLIS, MINNESOTA 55401
PHONE: 6 1 2.332.3654 FAX 61 2.332.3626
Project Number 15010.00
July 1,2015
COLLABORATIVE I#t .t .i i 3,l )
4[4
Architecture
Engineering
Interiors
Planning
July 1, 2015
Zack Carlton
City of Elk River
13065 Orono Parkway
Elk River, MN 55330
Re: City of Elk River Jackson Street Water Tower Condition Assessment
CDG Project #15010
Dear Zack,
We have completed the Condition Assessment for the Jackson Street Water Tower as proposed.
This report summarizes our evaluation procedures, along with our observations, conclusions
regarding the current condition of the water tower, and recommendations for repairs.
The services performed in evaluating this assessment and in preparing this report have been in
accordance with the level of skill and care normally used for this type of project. The
conclusions and recommendations discussed in this report are our best professional opinions
based on our knowledge of current design and repair of this type of building. No warranties are
expressed or implied.
It has been a pleasure to perform this service for you. If you have any questions, or if we can be
of further assistance, please feel free to call.
Very truly yours,
Collaborat' Design Group
C IMilkert, PE
Principal
100 Portland Avenue South, Suite 100
Minneapolis, Minnesota 55401
t 612 332/3654 f 332 3626
Affirmative Action, Equal Opportunity Employer www collaborativedesigngroup.com
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project#15010.00
TABLE OF CONTENTS
EXECUTIVE SUMMARY 1
INTRODUCTION 2
SCOPE OF REPORT 2
Review of Documents 2
Discussions with City of Elk River Personnel 2
Observations 3
DISCUSSION AND CONCLUSIONS 28
Introduction 28
General Discussion 28
RECOMMENDATIONS 30
PRIORITIES AND ESTIMATE OF PROBABLE COSTS 30
CCOLLABORATIVE DesignGroup,;nc.
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project#15010.00
EXECUTIVE SUMMARY
From a structural standpoint, all components of the Water Tower appear to be performing
well. Besides some more superficial issues, such as the presence of chipped paint, rust, and
lichen, all steel components are in average condition, especially for their age. The legs are
securely bolted to the concrete footings. There are no noticeable problems with any of the
tie rods, horizontal girders, or lattice work on the legs.
Two issues were observed, both located on the legs, which will need further maintenance
beyond the obvious painting. The first issue relates to some corrosion of the steel at the base
of the legs. This condition is hidden by the concrete that was installed to drain water from the
legs. It would be important to investigate the condition of the steel behind the concrete
further during the painting project by removing a portion of the concrete infill and inspecting
the steel. If the corrosion is worse than what is observed presently, some remedial action may
need to be done to strengthen the base, such as the addition of steel plates to replace the
loss of cross sectional area due to corrosion.
The second potential concern involves the steel splice plates connecting the leg sections.
Some of the plates are bowing as result of rust jacking, which occurs when the backside of
the metal rusts and expands, causing the front of the panel to move outward. Further
investigation and testing is recommended to confirm the severity of the corrosion and
determine the proper remedial action.
Paint is chipping on the Water Tower's legs, tie rods, and horizontal girders; the surface of
much of the exposed steel is covered in rust. The condition of the underside of the tank and
its surrounding walkway platform was observed to be similar to that of the legs, tie rods, and
girders, with a significant amount of weathered paint and rust. The sides of the tank
appeared to be in good condition relative to the rest of the Tower, but the roof and cap are
weathered with rust stains present from seams in the roof panels.
Considering that the Water Tower structure is no longer supporting the weight of water in a full
tank, maintenance and periodic observation will be all that is required in the future, and no
major structural modifications will be necessary. Some minor modifications may be necessary
as identified above.
All of the Tower's surfaces should be painted, including areas that may not be easily visible
from the ground, such as any exposed areas of steel angles, the inside of legs, and the
walkway platform. A new coat of paint will not only return it to its original appearance, but it
will also protect the steel from further rusting and deterioration.
The two potential structural issues should be further investigated with a more in depth study of
the areas in question. We recommend that a portion of concrete from one of the leg bases
be removed to get a better understanding of the condition of the steel. The bowing steel
splice panels should also be closely observed and tested to determine the extent of
damage.
COLLABORATIVE I)esignGroup,,n,.
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project #15010.00
INTRODUCTION
The Jackson Street Water Tower was built in 1920 by the Minneapolis Steel & Machinery
Company as part of a water works project that developed a fire protection program for the
City of Elk River. The Water Tower consists of a 100,000 gallon tank on a four leg, lattice-girder
trestle tower and stands approximately 129 feet tall. The Tower is currently coated with paint
that is assumed to be lead-based, and displays a non-historic City of Elk River logo, which
differs from the original silver tank and red conical roof. The structure was added to the
National Register of Historic Places on May 23, 2012.
The City of Elk River and the Elk River Heritage Preservation Commission have plans to restore
this structure. The intent of this Condition Assessment is to provide an understanding of the
required restoration work, along with the associated costs.
SCOPE OF REPORT
Review of Documents
Available documents regarding the Jackson
Street Water Tower were limited, but the
National Register of Historic Places
Registration Form was reviewed to gain an
understanding of the structure's construction
and history. This paperwork informed us that
kVi o
besides cleaning and painting of the Water
Tower, no alterations had been made to the
structure since its construction. -
F
Discussions with City of Elk River Personnel
The Jackson Street Water Tower is an iconic „"`Wi=t f t
landmark, and provides an important piece
of the identity and heritage of the City of Elk
River. The historic paint colors were silver for •
the main structure and tank, and red for the
sloped roof. Simple black lettering spelled
out "Elk River' on the side of the tank. ,
The water tank structure was constructed in
1920 by the Minneapolis Steel and Machinery
Company. The tank was constructed initially '
as a response to the many fires that occurred
in the downtown area. These fires were
difficult to fight since the railroad line created
a barrier between the downtown and the
river. After the construction of newer water
tanks in other locations, the Jackson Street
Water Tower was de-commissioned in 1960. «.
2
`COLLABORATIVE I)esignGroup,;n�.
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project#15010.00
Observations
Initial, ground-level observations were made on January 30, 2015. A more thorough site visit
was made on March 12, 2015 to further document the structure from both the ground and
the top of the Tower.
The following rating system was used in assessing the condition of the structure components:
• Good: The component is new, with no apparent defects.
• Average: The component is able to perform its originally intended function in
its current condition. Any defects are minor and do not affect the
performance of the component.
• Poor: The component is unable to perform its originally intended function
in its current condition. The component has major defects, but is
repairable.
• Unacceptable: The component is unable to perform its originally intended function
in its current condition, and cannot be economically repaired.
Replacement of the component is required.
Visual observations of the building are recorded below.
OBSERVATIONS REFERENCE PHOTO
1. Each of the Water 1st.'
Tower's legs consists
of two parallel steel
channels,which are Fkfi
bracketed on the
outside with a flat r 110 3%
•
steel plate,and on
the inside with small , ,.\
latticed bars.
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til
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3 COLLABORATIVE I)esignGroup,;nc.
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project#15010.00
OBSERVATIONS REFERENCE PHOTO
2. The Water Tower �-
was constructed in 14#
1920. _ Li, `
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I+'
Still
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3. The Water Tower - 't,
has four concrete .., .
footings with " tA �
'
varying amounts of
exposure due to the i<
surrounding t
landscape. All -
footings appear to a ,f w
be in average i ,
condition,with no "'
significant
deficiencies noted. u -.. „,.: o, pp 7.:-
�+�y�' �yJ�
y�q�'"IIS` '� pr" ��a,[e"� J. ± . ..+ -t YS a.klt t
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4 COLLABORATIVE DesignGroup,inc.
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project#15010.00
OBSERVATIONS REFERENCE PHOTO
4. The legs are . -
�' �
connected onto a P
steel base plate at
each footing with � #
steel angles,all of = , "j
which appear to be a 4
in average wf
condition.
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5. The steel base plate = �' ?
at the bottom of � '
each leg is bolted $.
into the concrete 4, 8 'r 9,,. ,
99 4
footings. These
f
bolts show no
significant ' ..
deterioration, and
are in average ti_.
_.
condition. `
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9..
1 . 3.
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`COLLABORATIVE DesignGroup,inc.
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project#15010.00
OBSERVATIONS REFERENCE PHOTO
6. The inside of the
base of each leg
has been filled with
concrete.
7. The sloped surface
of the concrete
allows water to
drain from the base
of the legs, but
water that flows to
sides of the legs has
begun to rust and deteriorate the . �
steel.
6 COLLABORATIVE ►esignGroup,inc.
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project#15010.00
OBSERVATIONS REFERENCE PHOTO
8. Water flows out of
the legs along the
steel at the edge of
the concrete,which
has caused the
steel to corrode.
Loss of cross-
sectional area of
the steel is '.
occurring on the
steel channels due
to corrosion. _ m
9. Loss of cross-
sectional area of
the steel is t°
occurring on the
steel channels due
to corrosion. fit;
'
COLLABORATIVE I)esignGroup,inc.
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project #15010.00
OBSERVATIONS REFERENCE PHOTO
10. Steel tie rods are ,
connected to the ._ s N
base of each leg. ... .
Steel legs and tie ,c ,
rods are covered 'f " .#
with a significant I
amount of rust and m
chipped paint.
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4 A A i _
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1 1. Rust and chipped <, ` ,
paint are prevalent `
' 4
on all steel tie rods
and legs.
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8
46'COLLABORATIVE 1)esigI it i oup,.:
City of Elk River
Jackson CDG Pro j
Street ect #Water 15010.00 Tower Condition Assessment July 1,2015
OBSERVATIONS REFERENCE PHOTO
12. Diagonal 4,-, .
re in overall tie rods
are
average condition ,a .r j
and are performing ' �' . `,
1
well, but are
showing a
t ° t
significant amoun `
iltr
of chipped paint \' .
and rust. ,
s�k:is k.. s`
13. Diagonal tie rods
/V are in overall P 111
average condition �
and are performing
well, but are
showing a 7 I ,'
significant amount "�
of chipped paint
ll1�
and rust.
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9 COLLABORATIVE I)esignGroup,mc.
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project#15010.00
OBSERVATIONS REFERENCE PHOTO
14. Tie rods are
connected with
steel turnbuckles.
Like the tie rods,
these turnbuckles
are covered with
rust and chipping
paint, but their
performance is
unaffected.
N.
15. A ladder extends
up the northwest
leg of the Water
Tower. Surface rust
and peeling paint '.
are visible in some a
areas, but no to ,
Ate w,
functional concerns k,,—/.1 1 2:, .l
regarding the ' : i '
ladder were of- *.,.
observed. ' Va4 tMO8
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, , k_ 100
10
COLLABORATIVE DesignGroup,inc.
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project #15010.00
OBSERVATIONS REFERENCE PHOTO
16. Lichen (organic s' ;`* , •sle,• . '
growth) is growing a ..• ,• " . .0.••
on the legs in some b .�1' ,�i . i•-•■
areas. ;,. •; ;
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r s pro " # •
s�Y fir . ii' .7 �. . .,.
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17. The lattice girder ��������......,,,,,,,,,
legs appear to be in
average condition,
with no structural
deficiencies
observed. Lattice
surfaces generally
seem to be in better . a� ,�;
condition than the
1#1.4.-A7 r � i' " f
flat sides of the legs, ., i�
with considerably
ile'
less chipped paint, ;;-�� #e
rust,and lichen. ► _ _4/
lip
Y,.
11
COLLABORATIVE
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project#15010.00
OBSERVATIONS REFERENCE PHOTO
18. The paint on the flat *=„
sides of the legs isf,
weathered;lichen
a
f 11444•44644.,
nd corrosion was
observed in some a
areas. ,� *•
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19. Each of the Water
Tower's legs is
essentially made up
of three sections, ,sue;,
with the longest at
the bottom and the
shortest at the top. ,, `"
The leg sections are ° , i
connected with i
steel splice plates '
on all four sides, /•
with some platesi _
inside the legs and ''',,,,,v
some outside. Note +
the two exterior +
plates indicated in w
the photo.
git 411,
12 0 COLLABORATIVE
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project#15010.00
OBSERVATIONS REFERENCE PHOTO
5 .r' r 1 0`
20. The presence of w
bolts and rivets r
within the leg _._.• / I •",
1
channels indicates �t •
that there is a steel °" `~-r1
F �
plate inside the leg, 41`, ,w(,
the condition of
which could not be r ! '�;�"
ascertained from. """�• �� ' 9
ground level. The k"� 1�•` d.
steel bracket r i 4,0 a" ,-
connecting the " 1 horizontal girder is r w r v; +i
•rusting and the t "�
bottom of the a k
exterior plate is /"" ��
expanding outward 1:P
slightly. 1 I
21. A steel plate is
attached to the �+
legs just above the .►
connection to the -+_ `'
horizontal girders. ' '� ">'
Each of these plates � ` .. ,v r
(eight total) appear 4' f
:a.
to be in average " &- 1
t
y
i
13 COLLABORATIVE I)esign Group,in,.
City of Elk River
Jackson CDG Street Water Tower
10.00 Condition Assessment
Project #150 July 1,2015
OBSERVATIONS REFERENCE PHOTO
22. The plates on the
outside of the Water
Tower are in
average to poor
condition,with vl
some showing
significant rust and
expansion.
/11
i
23. Close up of one of
the outside steel
plates. It appears
as though water
has corroded the 4.
backside of the ' �,
plate,causing the ; 1:_
steel to expand and
bow outward, a
condition known as f,'
rust jacking. ' ' t
14 COLLABORATIVE I)esignGroup,;n,.
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project#15010.00
OBSERVATIONS REFERENCE PHOTO
24. Another instance of Z
Ili
4
rust jacking. While 4.
r
this plate is in better 4 +
condition than
tib
others,it can be
expected to N t w
continue to • j
degrade. .
A& ilk
ork
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A rt
4 Ai
AL AiIt
A
A
Alk AL
25. A horn sits on a a -
platform perched
atop two horizontal
steel girders, %- -
requiring an .M.
electrical conduit
running up the -
northwest leg from
the ground- The
horn and platform ' ',;
contain surface rust " ►
and weathered
paint,but no major
deficiencies. It is
unknown if the horn
is functional. 1 �1
15
4 COLLABORATIVE DesignGroup,,nt.
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project#15010.00
OBSERVATIONS REFERENCE PHOTO
26. Horizontal girders
are connected to !� r r the legs with steel {` .1
/1/$17 "
angles and rivets.
There are eight total ,
girders,connected
just below the
seams between leg ' :, r+L
sections. All girders ;
appear to be in ;•_
average condition,
with just some rust, fp.
weathered paint,
and lichen noted 4
on their surfaces.
* 44444 ''' 4(14' -
27. Lichen is growing on
horizontal girders.
16 COLLABORATIVE
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project #15010.00
OBSERVATIONS REFERENCE PHOTO
28. Rust and chipped Ipplir
paint is evident on
the surface of
horizontal girders.
29. At the epicenter of
the four Tower legs
is vertical steel tube
that encloses an
eight inch stand
pipe connecting
the tank to the
water system. Eight
tie rods connect the
center tube to the
Tower's legs.
4
17
`COLLABORATIVE DesignGroup,gin,.
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project#15010.00
OBSERVATIONS REFERENCE PHOTO
30. An access hatch
leads underground -
underneath the -.
Water Tower. K
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Y _
ir,
•
31. A small hatch allows '50'
access to the
enclosed stand
pipe.
18 COLLABORATIVE ,)esignGroup,inc.
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project#15010.00
OBSERVATIONS REFERENCE PHOTO
32. Some minor rusting1;
and weathered '�;
paint were _
observed on the
vertical tube. y
i ` "..�} 4{y' �t.. 'z ye�.��i/ :-.,.1''';'- 'i''''} 1r'kWy,,�"'C * id
,•*'•,e ...• • '''•',z- .-'••-A "s'` -F7,---%'*,,P, i,,,,(4 ,i,.,,,,
,. ,, A' -."., ,.....,,,,,'"*.N=1,, j ,...r 4: k,c,,,,,,i,$ki I/I..' �—r ,}--�`,:nej, a':_- ^ } ,� 1y. t,* 4.r} *1'
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ss��`���a..-ate '� �s� ,'�`Y�` x ve>'�,_'-,..,%7:-. � w
33. The vertical tube is
bolted into a
concrete pad. The
surfaces of the bolts
are covered withr
rust and dirt, but are
performing well.
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' '.if) ' . ,1 ,.*4 7 )'1,, ;4, 4, , ', ,
M•
, ,.,,,,, ,....- •-• .c. Ic ---‘......1',A'.`" : I -
''''." ' A ,i4 0,4.,
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19 COI 1 ABC)RATIVE
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project #15010.00
OBSERVATIONS REFERENCE PHOTO
34. The standpipe P.I."--
h
enclosure extends /���
from the ground to s, z `5
the underside of the
tank. if r f
at
4.
35. The underside of the
•tank is in average ` `, f:
condition,with
some rusting and ; . , Y
weathered paint.
1 f
20 COLLABORATIVE
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project#15010.00
OBSERVATIONS REFERENCE PHOTO
36. The walkway .vj ' '° . '. �
platform ,; {
surrounding the F f 1...`;‘,'4.
tank is in average ,.\ ,pr.
condition,with p \ � ' fit" ,
!
weathered aint. y��! .'-! 1,-•.'' ', /
1 % ' .44'46A'r ", .
44 J 'ice, i` ;*1
a ♦,: .,R}lit.
s. i �, i
ye e 5 ; ,
cc ;? '� ‘,.,;,-. t._,..
37. Sections of the steel "="
plate walkway are V ! ,
riveted to steel - t `,.t.,
. -,
splice plates
beneath the t ..
.
platform. , ,, .},
t ` S t .
411' a , -''',1,'T -t 0'.) q j'.
*, � try , ,,�.
21 C COLLABORATIVE i)esignGroup,mc.
City of Elk River
Jackson Street Water Tower Condition Assessment July 1.2015
CDG Project#15010.00
OBSERVATIONS REFERENCE PHOTO
38. Steel plates and
rivets beneath the
walkway platform
connect the
>xT
sections of steel
walkway plates.
The walkway has a
latticed steel .....,:...-7-----7,_„_. �' ___. _�..
guardrail,which- / �-.'= "` ° :~�"
like the platform-is /° T, - ��'"' #
weathered but in , 'r/ ,; _
average condition. s' -
/ ./
.
39. The latticed / \ ,
handrail around the
tank is in average -%__ E
condition overall, 3 '""
but features many _ , '',- , �
areas of chipped
paint and rust. t
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Ii
4 irj'
t.
- y t,
1611,( )'' ‘"‘\., ' 8*i. '',,' . •\''' '''"°' -:\:: '
___
.4 L h
22 COLLABORATIVE DesignGroup,inc.
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project #15010.00
OBSERVATIONS REFERENCE PHOTO
40. The latticed - " '"
f op
handrail around the . 0.,... 3 X
tank is in average 1
condition overall,
but features many �'
areas of chipped �` {.', ,,,
paint and rust. • �,
fir ! • 4s, 4 '
1 .,,,-,.., rl • ::..: -: z...:;,,...
Ai ‘i. ,„, ( „4.' 7 ' )
41. The four legs extend
inside the walkway
platform and are (..
connected with
d
steel angles and C t ;
rivets to the vertical
surface of the tank. ,4rFlot,
Ifrfr
• s
.... • ,e. ....,
I ,
,,
N
4
23 COLLABORATIVE I)esignGroup,inc.
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project #15010.00
OBSERVATIONS REFERENCE PHOTO
42. View looking down
inside of one of
the Water Tower's
legs. .� r
I ,
43. The side of the tank
is in average
condition.
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24
CO COLLABORATIVE I)esignGroup,inc.
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project #15010.00
OBSERVATIONS REFERENCE PHOTO
44. The side of the tank
is in average
condition.
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- 1.111101711 4440,11111111# ,IL:1111111, 4
lor 41
dor
45. A second ladder j>
rises along the side
of the tank. Like the i—
ladder along the 4
northwest leg,this :� �
ladder features
surface rust and .��
chipped paint,but
is performing well
and has a good
connection to the "F
Water Tower.
25 COLLABORATIVE DesignGroup,inc.
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project#15010.00
OBSERVATIONS REFERENCE PHOTO
46. A third ladder
allows access to the
conical roof of the
tank and the cap
'4\\\\
on the very top of
the Water Tower.
This ladder can dis- t
connect from the
second ladder, and
pivot around the t
cap at the top to -�
provide access =�.
around the entire t
circumference of = r
the roof. -� a
4-04 t
47. Some minor rusting
and water staining
was observed at
seams and the
edge of the tank on
the underside of the
eave.
°,.
26 COLLABORATIVE I)esignGroup,inc.
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project #15010.00
OBSERVATIONS REFERENCE PHOTO
48. The conical roof is ,'
rusting at panel
seams.
z, �•
Y ` •
4r
•
49. The conical roof is Notigeit
rusting at panel
seams. •
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}
•
27 COLLABORATIVE DDesignGroup,in<.
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project#15010.00
OBSERVATIONS REFERENCE PHOTO
50. The cap atop the A ,
roof appears to be
in average
condition.
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DISCUSSION AND CONCLUSIONS
Introduction
This condition assessment focuses on two main points concerning the Jackson Street Water
Tower: the overall structural condition of the Tower, and the requirements to preserve the
Tower to maintain its integrity and value. Part of the preservation plan is to restore the water
tower to its original appearance,which will require extensive work to clean and remove old
paint, rust, and growing lichen. A few rusting areas, such as at connecting splice plates on
the outside of the legs and deteriorating areas within leg bases also present a concern from a
structural standpoint.
General Discussion
From a structural standpoint, all components of the Water Tower appear to be performing
well. Besides some more superficial issues, such as the presence of chipped paint, rust, and
lichen, all steel components are in average condition, especially for their age. The legs are
securely bolted to the concrete footings. There are no noticeable problems with any of the
tie rods, horizontal girders, or lattice work on the legs.
The Water Tower's legs consist of two steel channels sitting parallel to each other and riveted
to a long, flat steel plate on the edges on the outside perimeter of the Tower and small
28 COLLABORATIVE
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project#15010.00
latticed bars on the inside edges. Put together, these pieces form a square leg that rises to
the tank in three sections. Each section is connected with four steel splice plates, two of
which are bolted and riveted inside the legs, and two that are bolted on the legs' exterior
surfaces.
Two issues were observed, both located on the legs, which will need further maintenance
beyond the obvious painting. First, the base of each leg is filled with concrete that promotes
the drainage of water out of the leg assembly. It appears that water naturally flows to the
sides of this concrete and along the edge of the inside of the legs,which has resulted in some
deterioration and loss of cross sectional area of the steel. The thickness of the steel channels
is important, as this is what transfers the load of the water tower to the foundation. At this
time, the condition of the steel is behind the concrete is unknown. It would be important to
investigate the condition of the steel behind the concrete further during the painting project
by removing a portion of the concrete infill and inspecting the steel. If the corrosion is worse
than what is observed presently, some remedial action may need to be done to strengthen
the base, such as the addition of steel plates to replace the loss of cross sectional area due
to corrosion.
If it is determined that additional steel needs to be added, a sample of the steel should be
taken and tested to determine its physical properties. Steel produced during the time of the
construction of this water tower did not have the same physical properties of modern day
steel, and may not be able to be welded. This testing information will inform the design of the
connection of any additional steel members, if needed.
The second potential concern involves the steel splice plates connecting the leg sections.
Some of the plates are bowing as result of rust jacking,which occurs when the backside of
the metal rusts and expands, causing the front of the panel to move outward. This appears
to be happening exclusively on the eight plates on the outside perimeter of the Tower, which
is not surprising since the slope of these surfaces allows water to travel down the legs and flow
behind the connection plates. Since these plates hold the legs together, they are integral to
the structural integrity of the Tower. If the plates continue to corrode, the connection
between each section will weaken and the structural capacity of the legs will diminish.
Paint is chipping on the Water Tower's legs, tie rods, and horizontal girders; the surface of
much of the exposed steel is covered in rust. A significant amount of lichen is also growing on
some of these surfaces.
The condition of the underside of the tank and its surrounding walkway platform was
observed to be similar to that of the legs, tie rods, and girders, with a significant amount of
weathered paint and rust. The sides of the tank appeared to be in good condition relative to
the rest of the Tower, but the roof and cap are weathered with rust stains present from seams
in the roof panels.
Considering that the Water Tower structure is no longer supporting the weight of water in a full
tank, maintenance and periodic observation will be all that is required, and no major
structural modifications will be necessary. Some minor modifications may be necessary as
identified above.
29
COLLABORATIVE DesignGroup,..
City of Elk River
Jackson Street Water Tower Condition Assessment July 1,2015
CDG Project #15010.00
RECOMMENDATIONS
It is the City of Elk River's intent to restore the Water Tower to its original appearance,which
consisted of mostly silver painted steel except for black lettering and a red roof. In order to
do so, chipped paint, lichen, and rust will need to be removed to provide for the adhesion of
the new paint. Because the paint is likely to contain lead, all removed paint will need to be
captured by qualified workers and properly disposed of. It will not be necessary to strip all of
the paint off of the water tower down to bare steel. Any lead based paint that is adhered
well can be encapsulated with the new paint. Proper cleaning and preparation of all
surfaces will need to be performed prior to cleaning.
All of the Tower's surfaces should be painted, including areas that may not be easily visible
from the ground, such as any exposed areas of steel angles, the inside of legs, and the
walkway platform. A new coat of paint will not only return it to its original appearance, but it
will also protect the steel from further rusting and deterioration.
The two potential structural issues should be further investigated with a more in depth study of
the areas in question. We recommend that a portion of concrete from one of the leg bases
be removed to get a better understanding of the condition of the steel. Areas of rust and
deterioration are present on the exposed steel just above the concrete, and the possibility
exists that water has been able to seep between the metal and concrete and cause unseen
damage to the steel. The bowing steel splice panels should also be tested to determine the
extent of damage.
PRIORITIES AND ESTIMATE OF PROBABLE COSTS
Description Estimated Cost
Additional Testing $ 4,000
Steel repair (if required) $ 5,000
Painting $60,000
Sub Total $69,000
Contingency, 15% $10,350
Design Fees, 8% $ 5,525
Total $84,875
30
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