Chilled Water Line Hanger Rods
Chilled Water Line Hanger Rods
(OP)
I am dealing with the following situation on one of the projects we designed. During punch list, we noticed that contractor supported chilled water pipes to the bottom of a sloping roof beam (the beam span is perpendicular to the roof slope; the beams are 16 inches on center). The contractor bent the all-threaded rod and bolted it to the bottom flange.
The detail we supplied utilizes an angle that is bolted to three roof beam bottom flanges and the all-thread rods were to bolt to the angle and we called for beveled washer under the nuts.
I do not think what the contactor did is a good practice since it will introduce bending to the rod. Our company is being challenged by the contractor and owner to leave it as is.
As I look, all I can find is the 2004 RCSC specification section 6.1.1 which reads as follows:
"Sloping Surfaces: When the outer face of the joint has a slope that is greater than 1:20 with respect to a plane that is normal to the bolt axis, an ASTM F436 beveled washer shall be used to compensate for the lack of parallelism."
I would like to get my hands on a documented reference (established one such as AISC manual or publication) so I can show them written documentation why they should change it. Does any one have more details or references?
Please feel free to comment on this situation as well.
The detail we supplied utilizes an angle that is bolted to three roof beam bottom flanges and the all-thread rods were to bolt to the angle and we called for beveled washer under the nuts.
I do not think what the contactor did is a good practice since it will introduce bending to the rod. Our company is being challenged by the contractor and owner to leave it as is.
As I look, all I can find is the 2004 RCSC specification section 6.1.1 which reads as follows:
"Sloping Surfaces: When the outer face of the joint has a slope that is greater than 1:20 with respect to a plane that is normal to the bolt axis, an ASTM F436 beveled washer shall be used to compensate for the lack of parallelism."
I would like to get my hands on a documented reference (established one such as AISC manual or publication) so I can show them written documentation why they should change it. Does any one have more details or references?
Please feel free to comment on this situation as well.
Regards,
Lutfi






RE: Chilled Water Line Hanger Rods
RE: Chilled Water Line Hanger Rods
Regards,
Lutfi
RE: Chilled Water Line Hanger Rods
Regards,
Lutfi
RE: Chilled Water Line Hanger Rods
RE: Chilled Water Line Hanger Rods
RE: Chilled Water Line Hanger Rods
RE: Chilled Water Line Hanger Rods
smb4050 is right. Hanger rods subject to axial tension and bending do not follow classical mechanics. If you have any expansion/contraction of your piping system, the bending stresses can skyrocket under tension.
Bending a rod at the thread is such a bad idea, you may have trouble finding anything written on it. First of all, the machining of the thread has created a stress concentration around the circumference of the bar. OK, so there are zillions of threaded parts doing just fine. But bending the threaded bar into a permanent set means the material has been strained beyond yield across the stress concentration. Unless the material was properly heated before bending, I would expect there to be cracks at the root of the threads.