Backup Documents 03/11/2011 Item #15DHillerGeorgia
From: schrzanowski2 @comcast.net Gnu V+
Sent: Friday, March 04, 2011 11:30 AM
To: HillerGeorgia
Subject: Clam Pass / Bay boardwalk drawbridge
Attachments: 026.JPG; Pile splicesJpg; 100_1435.JPG; 100_1429.JPG; 035.JPG
Dear Commissioner Hiller:
150-
i *In &
The attached (dated) pictures from 2008 and 2010 show the underside and supports for the Clam
Pass Boardwalk Bridge that is the route for many trams full of people daily from the Clam Pass public
parking to the Clam Pass beach.
Please note the three horizontal wood fenders on each side of the bridge segment under the
aluminum drawbridge. All of those fenders should be parallel to each other and to the water surface.
The ones on the east side (nearer the mangroves) are parallel to the water surface (at least
reasonably horizontal). The ones to the west are not reasonably horizontal. That's because the piles
at that one end rotted out where a splice was done in the middle of the water column . One pile leans
noticeably. There's a large concrete - filled corrugated metal collar at the water line of that pile and the
metal around the collar is beginning to corrode.
Also please refer to the attached pile splice drawing.
It appears to me that when they were driving the pile, it apparently wasn't long enough, so they
spliced another pile on to it. The type of splice they used is indicated on the attached drawing on
figures 1, 2, and 3. They sawcut longitudinally down the center axis and then halfway through the pile
from either side (figure 1). They do the same with the pile extension (figure 2) and then install
through bolts with washers to hold the splice together. The end product looks like what's in figure 3. 1
think they did this with, at least, all four piles that support both ends of the drawbridge.
The problem with this splice method is that the Chromated Copper Arsenate preservative doesn't
penetrate to the center of the pile so the sawcut left the heart of the pile exposed to marine
organisms. It rotted out. About 4 or 5 years ago (maybe more) the rotting was so bad that I could
stick my hand into the middle of the splice and open it up and wave it around. The through bolts were
totally corroded through. The pile was headed toward the type of failure shown in figure 4.
Parks and Rec had noticed the settlement of the deck and were monitoring it. A fellow engineer,
Terry Kepple, and I were a little more concerned and we investigated the pile and found the condition
shown above. We canoed that area almost weekly for years. We called it to the county's attention
and their solution was the collar. We were told that the collar was temporary for a couple of years
and that a permanent fix would be planned and done.
It has been a few years, and I have a few concerns.
The drawbridge acts as a pile driver against the piles under its west end support. The constant
impact loading of the fully loaded trams over the duration of years puts forces on the collar and
splice. It is not a stationary load.
If you look at figure 4 on the attached drawing... picture two wedges sliding past eac o�eat's an
efficient way to multiply the force exerted on a member. I worry that we can't see what's going on
inside the collar and under the collar.
I see money being spent for new projects and wonder why money can't be allocated to a permanent
repair for this project.
When they did the repair they didn't jack the bridge level. They didn't plumb the pile.. They didn't
take the bows out of the cross bracing. They just put on a collar. As a constituent and a member of
the public who kayaks and canoes under this bridge on a regular basis, I'd like to know if the proper
repair and /or replacement of this bridge is on anyone's to -do list.
Thanks for your consideration in this matter.
Stan Chrzanowski
2504 Sailors Way
Naples, Florida
P.S. Has that drawbridge ever been opened to let a craft pass through? How long ago? Is a log
kept? If the drawbridge is never used, maybe it's not needed.
Feel free to forward this to any and all concerned parties.
,WUN
\\!§ .�\
\ �� � \ `� � ^ �' �
I
L-.-m
k;
16
, » w��\ �� \ \ \ .� �: \
I
SL,, -1 ^
I ia
t
4
--AFP
11
If
�q
o
I.J
3
15 0 • t�4#
-.-0%-, -- -A%P
r, I