Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

Register Log in
  • Congratulations KootK on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Crane Rail Fixture

Status
Not open for further replies.
SJBombero

SJBombero

Structural
Dec 1, 2014
174
I fabricated a fixture to perform crane rail surveys but it doesn't seem to be as accurate as I had hoped. My process is to place the aluminum bar on the rail and rotate it until the dowel pins make contact with each side of the rail. Then use the bubble level on the prism to level it out before taking a shot with a 3 deg total station. The client is claiming that the numbers are off. I can't see what source of error I am missing unless the technician holding the fixture is just doing a sloppy job. On the most recent project, the rail was about 20 ft up, 40 ft span and 150 ft runway length. The station was set up about 2/3 the runway length. After the survey, the client straightened the runway with a piano wire and calibrated tape measure. I surveyed it again and it still didn't meet specifications. I'm starting to wonder if my process is flawed.
 
 https://files.engineering.com/getfile.aspx?folder=294faeeb-91a7-4b64-83ef-d5e8fe831bf3&file=Crane_Rail_Fixture.pdf
Replies continue below

Recommended for you

Sort by date Sort by votes
I'm not into surveying, but there are so many possible sources for error that I would think that it would be difficult to get a repeatable reading. Can you not secure a small bent plate (steel or aluminum), that wraps around the rail, to the bottom of a total station 'rod'?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Do you feel any better?

-Dik
 
Upvote 0 Downvote
SJBombero said:
Then use the bubble level on the prism to level it out before taking a shot with a 3 deg total station.
Click to expand...

1. Bubble levels to prisms are one source of error. Depending on the brand, some are accurate to only 40".

2. Did you mean your total station has a 3" angle measurement accuracy, not 3 deg?

What was the difference between your measurement/s and your clients?

 
Upvote 0 Downvote
Bending it in a channel section helps with the stiffness...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Do you feel any better?

-Dik
 
Upvote 0 Downvote
Status
Not open for further replies.

Part and Inventory Search

Sponsor

Back
Top Bottom