Scanning our way up two tall towers

Discuss all Oil & Gas Industry related issues here.
Post Reply
User avatar
jcoco3
Global Moderator
Global Moderator
Posts: 1393
Joined: Sun Mar 04, 2012 5:43 pm
Full Name: Jonathan Coco
Company Details: Forte and Tablada
Company Position Title: AMM Division Leader
Country: USA
Linkedin Profile: Yes
Has thanked: 1 time
Been thanked: 4 times
Contact:

Scanning our way up two tall towers

Post by jcoco3 » Tue May 27, 2014 2:57 am

Just thought I would share this story about one of our last adventures to help anyone who may attempt such work, and ask if anyone else with similar experience can share and propose some better, less stressful workflows.

We were recently asked to scan two petrochemical towers and provide all geometry related to the ladders and platforms for a replacement project. They were nearing the end of their useful life and were showing signs of decay. They were not so bad that we were in any real danger, but they were considered dilapidated enough that we were the last to be granted permission to climb them. After an incredibly long safety meeting about fatigue and potential harness tie-off points, everyone gave us their blessing and permission to climb over the red barricade tape around the first ladders.

The short tower was 110' tall and the other tower 250'. At first I didn't consider these heights being very high since I have jumped from many thousands of feet before just for fun...in this instance I was wrong :shock: For the necessary density, accuracy, and line of sight, scanning from the ground was not sufficient. It was necessary to scan at each platform all the way up to capture the top of the platform I was standing on, the next ladder, and the bottom of the platform above me. I started by climbing about halfway up the taller of the two, placing spheres with clamps at specific points to tie the two towers together and make ties available between scans on the shorter tower. The spheres and clamps were carried in a large backpack. While I was climbing, my co-worker was placing some checkerboards for any return visits and making the first scans around the bottom of both towers. After these scans were complete, I stuffed our Faro scanner in another backpack with the Gitzo tripod strapped to the side and began the climb of the short tower. Because of the awkwardness of wearing a harness and backpack while climbing through ladder cages, I had to wear the backpack in front of me. This was more comfortable and made climbing easier. The first tower went without much trouble, and spheres that we placed at ground level were visible almost all the way to the top. I also placed additional spheres on my way up. By the time I made my way down it was time for lunch and a short break. After getting a belly full of food, which I regretted later, I began my climb of the tall tower. The first half of the 250' tower also passed by without much trouble, but after a few more platforms things got interesting. We had been battling wind direction and steam all morning, and during a couple of the longer ladder climbs I had to stop midway because I could not see my hands in front of my face gripping the ladder rungs. I took breaks along the way at each platform, but I knew there was much further to go. When I was about 85% complete with the tall tower climb, fatigue started to set in, and my arms started to get very heavy. The weight from all the safety gear and the scanner strapped to my chest finally started to take its toll. My legs were now doing most of the work and my hands and arms were working more or less like fixed metal hooks with just enough strength to grasp the next rung confidently. Most of the ladders on the top half were somewhere between 35' and 40' in length which felt like a mile while climbing. Another unanticipated feeling that I became aware of was the lack of objects in my peripheral vision as I climbed higher and higher. It is a very strange feeling, and while the tower in front of my face was very large in diameter, by the time I was nearing the top it looked like a broomstick that I was climbing into the stratosphere. You know how people always say, "Don't look down"? Now I say don't look up either. When you look up at the top of a tall static object, the clouds moving in the background can make you feel like you are moving relative to the tower. It is not a pleasant feeling :( The second to last platform had a slight downward tilt which was a little un-nerving. By now I was already hugging the tower at each level so it didn't matter much. Finally at the last platform I got to take a long break and enjoy the view, which was incredible. 250' up might as well have been a thousand feet! From that perspective the top of the 110' tall tower, which I previously thought was pretty high, looked like it was sitting directly on the ground. I could also see well-known buildings far off in the horizon which were approximately 22 miles away according to google earth. At the top I signaled my co-worker to start gathering up the spheres from the first tower, while I began my decent gathering my share of spheres. The climb down was flawless and easy, and I almost kissed the ground when I reached it.

There is definitely something to be said about scanner and tripod portability. I doubt we would have even attempted this project with a larger scanner, and I have since purchased a more compact tripod. For the next project I am considering building some new prism adapters for our scanner that allows the prism to tilt downward making it possible to shoot them from the ground at a reasonable angle with a total station. See this post for reference pictures: http://www.laserscanningforum.com/forum ... =10#p26344

Here are some screenshots from our project to put the height into perspective:
iso.PNG
elevation.PNG
section.PNG
top.PNG
Notice the bad registration in the last picture? We fixed it, but it is worth noting that on the top half of the tall tower we were unable to place any targets, so all upper level registration was performed by finding mean contrast points and corner points on adjacent towers.

I know there must be many people who have done this before or even more exciting projects, but I just wanted to pass along this experience to the rest of the non-daredevils so that they are a little more prepared for some of the strange phenomena they may encounter when dealing with such heights.
You do not have the required permissions to view the files attached to this post.

User avatar
Jason Warren
Administrator
Administrator
Posts: 3145
Joined: Thu Aug 16, 2007 9:21 am
Full Name: Jason Warren
Company Details: Laser Scanning Forum Ltd
Company Position Title: Co-Founder
Country: UK
Skype Name: jason_warren
Linkedin Profile: Yes
Location: Retford, UK
Has thanked: 3 times
Contact:

Re: Scanning our way up two tall towers

Post by Jason Warren » Tue May 27, 2014 7:43 am

Nice one Jonathan... that's one type of job I wouldn't be in a hurry to do! :D
Jason Warren

Mikolajczyk
I have made 50-60 posts
I have made 50-60 posts
Posts: 55
Joined: Tue Jan 24, 2012 2:49 pm
Full Name: Marcin Mikolajczyk
Company Details: MM Survey ApS
Company Position Title: Technical
Country: Denmark
Linkedin Profile: Yes

Re: Scanning our way up two tall towers

Post by Mikolajczyk » Tue May 27, 2014 7:54 am

Really nice job. I discovered last year that I would not be able to climb it. For me it was not the height but I could feel the movement of the tower and that felt unpleasant.

Sometimes instead of a tripod I use 1,5 inch pipe with 3/8 thread.
https://www.dropbox.com/s/luxw30ph0stdt ... 083933.jpg

This, plus clamp can fit into a pocket and you will be able to fix a scanner. I guess that every metal workshop will be able to make it.

User avatar
jcoco3
Global Moderator
Global Moderator
Posts: 1393
Joined: Sun Mar 04, 2012 5:43 pm
Full Name: Jonathan Coco
Company Details: Forte and Tablada
Company Position Title: AMM Division Leader
Country: USA
Linkedin Profile: Yes
Has thanked: 1 time
Been thanked: 4 times
Contact:

Re: Scanning our way up two tall towers

Post by jcoco3 » Tue May 27, 2014 8:04 am

Marcin,

I know that feeling, but fortunately these towers were very stout and did not sway a all. I am curious about the 1.5 inch pipe. I saw your picture, but I don't understand how your use it. Do you clamp it to handrails or does it fit in something else? I might consider using something like this next time.

Oatfedgoat
Global Moderator
Global Moderator
Posts: 1039
Joined: Mon Oct 06, 2008 8:31 pm
Full Name: Matthew McCarter
Company Details: Costain
Company Position Title: BIM Manager
Country: England
Linkedin Profile: Yes
Has thanked: 1 time

Re: Scanning our way up two tall towers

Post by Oatfedgoat » Tue May 27, 2014 8:15 am

Great story, thanks for sharing.

Have you ever thought about starting a blog for such tales? I am sure you would be suprised at the number of reads they get.

User avatar
blazaj
V.I.P Member
V.I.P Member
Posts: 465
Joined: Tue Jan 26, 2010 1:07 pm
Full Name: Jiri Blazek
Company Details: BW precision systems sro
Company Position Title: Managing Director
Country: Czech Republic
Linkedin Profile: No
Contact:

Re: Scanning our way up two tall towers

Post by blazaj » Tue May 27, 2014 8:27 am

Great laserscanning story Jonathan!

User avatar
jcoco3
Global Moderator
Global Moderator
Posts: 1393
Joined: Sun Mar 04, 2012 5:43 pm
Full Name: Jonathan Coco
Company Details: Forte and Tablada
Company Position Title: AMM Division Leader
Country: USA
Linkedin Profile: Yes
Has thanked: 1 time
Been thanked: 4 times
Contact:

Re: Scanning our way up two tall towers

Post by jcoco3 » Tue May 27, 2014 8:30 am

Thanks guys,

Matthew,
Actually, the thought had crossed my mind. I was a little worried that this post was too long and possibly abnoxious. I guess in the absence of a place to blog I just wrote it down here so the experience didn't go to waste :ugeek: It brings up another point though. How long is too long for a post? I have another post I have been working on that I will probably have to pdf and attach due to length but it is difficult to insert video and allow for easy quoting and response in a pdf.

Mikolajczyk
I have made 50-60 posts
I have made 50-60 posts
Posts: 55
Joined: Tue Jan 24, 2012 2:49 pm
Full Name: Marcin Mikolajczyk
Company Details: MM Survey ApS
Company Position Title: Technical
Country: Denmark
Linkedin Profile: Yes

Re: Scanning our way up two tall towers

Post by Mikolajczyk » Tue May 27, 2014 8:36 am

Jonathan

Here two more pictures to clarify
https://www.dropbox.com/s/92is76ggow9bp ... 092444.jpg

https://www.dropbox.com/s/ugwgfszwhdsoc ... 092520.jpg

Yes, I mount it on a handrail. You will find that clamp on every plant.
Sometimes I will use that metal pipe from the picture to clamp it on a handrail and then scanner will be clamped outside handrail to scan the facade.

User avatar
jcoco3
Global Moderator
Global Moderator
Posts: 1393
Joined: Sun Mar 04, 2012 5:43 pm
Full Name: Jonathan Coco
Company Details: Forte and Tablada
Company Position Title: AMM Division Leader
Country: USA
Linkedin Profile: Yes
Has thanked: 1 time
Been thanked: 4 times
Contact:

Re: Scanning our way up two tall towers

Post by jcoco3 » Tue May 27, 2014 8:42 am

Ah now I understand. That's a scaffold clamp. What a great idea! I will have to get one and fabricate a little stub pipe just like your mount. Thanks for sharing, I know this will help me in the future :)

User avatar
IngSayyad
V.I.P Member
V.I.P Member
Posts: 239
Joined: Thu Dec 19, 2013 12:10 pm
Full Name: shahzad sayyad
Company Details: Ingenieurbuero Drecoll
Company Position Title: Entwicklungsingenieur
Country: Germany
Skype Name: shah.baba_2012
Linkedin Profile: No
Location: Hannover
Contact:

Re: Scanning our way up two tall towers

Post by IngSayyad » Tue May 27, 2014 8:44 am

It's really a nice work but I'm not comfortable to do it due to height feeling.
Dr.-Ing. Shahzad Sayyad

Post Reply

Return to “Oil & Gas Industry”