No more rivets - computerized steel fabrication

Submitted by Jeff Buster on Fri, 11/04/2011 - 22:14.

using air impact wrench to pre tighten structural steel bolts followed by torque wrench at 475 foot pounds 

Here is a steel pedestrian bridge spanning a highway being connected to the wheel chair slope compliant ramp on one side of the highway.  

The bridge was pre-assembled at the steel fabricator to confirm the fit of the bolts.  (475ft/pds torque)

This is a spectacular curved connection with double (inside and outside) bolt plates on both the web and the flanges. 

This is where the computers come in to play:  on these curved surfaces the bolt hole spacing on the outside radius plate is greater than on the inside plate.  Not much greater - and the computer can calculate the difference in the circumference and precisely locate the holes in the outside plate, the beam, and the inside plate so that all the bolts slide through all three steel membranes.  

Night work.

Very cool.


Other issues:

1. Why spend money for pedestrian infrastructure?

2. Why do many publicly bid contracts go way over budget with extras?

3. Did the General Contractor on this job have to sent a representative to the steel fabricating sub contractor to ensure that the sub fabricated this structure and did not work on another job with the pedestrian bridge steel stock?  (answer, "YES") 

Tighten-Up-P1550292.jpg91.24 KB
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