Mono Rail attachment to ceiling with expansion anchors 3

[kaffy]

Good evening fellow engineers,

I am working on a project where I need to provide a 6' long beam with a capacity of 1 tonne (short load duration). As a beam trolley will be used on the beam, I will be following CMAA. The beam will be attached to ceiling(8in concrete) with post installed anchors. I will be doing the following checks
1: Beam size (Mono rail beam analysis)
2: Post installed anchors size (6 anchors, tension load on each anchor = 2800/6 = 466lb,I will use profis to determine the embedment depth, size and type) (2800 lb = capacity + approx weight of beam)
3: I will add the plates on ends to acts as a stopper

As it is overhead application and only anchors will be holding the beam and weight, I want to make sure I am not missing anything. Do I need to check anything else?

Thank You
Newbie

 

[driftLimiter]

Just be caution for anchors with sustained tension. There are additional requirements for those. The failures at the 'Big Dig' led us to realize sustained tension is a special case. Hilti has developed the Undercut anchor to help with that (HDA).

 

[dik]

You should use a non-creep adhesive. The problem at the Big Dig was caused by creep failure of the anchors. If really short term, undercut anchors are not likely necessary, but they are safer for sustained loading. Do you have 6 anchors at each support? Can you get by with 2 or even 4? Critical spacing will 'force' a larger anchorage plate, and fewer anchors will minimise this. Also for hoists, I prefer adhesive anchors; I don't like mechanical anchors for hoists. Just a personal quirk...

Sorry, I looked at your picture and you are anchoring the top flange to the concrete... pretty much the same, but 6 ancors could be OK. Check for prying action of the flange connection.

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

 

[OldDawgNewTricks]

I'm not sure what type of loading you are designing for, but fatigue and impact loading are often important considerations for crane and hoist supports. From a quick glance at Hilti's catalog it does not look like they list any of their products as "suitable" for fatigue or impact loading, only "may be suitable". Their footnotes say that there is only reference data available based on European testing, so you might want to look into whether it is compatible with your design criteria.

 

[kaffy]

thank you very much guys

 

[XR250]

I'd be careful dividing the demand by the number of anchors. Unless the beam is infinitely stiff, the anchors closest to the trolley wheels will be working the hardest. I'd consider 1/2 tonne per anchor or more.
Also, it is difficult to mount an i-beam as shown without drilling diagonally. Perhaps consider adding top plates that are wider than the section so the holes can be drilled vertically.

 

[human909]

THIS ==>>

I'd be careful dividing the demand by the number of anchors. Unless the beam is infinitely stiff, the anchors closest to the trolley wheels will be working the hardest. I'd consider 1/2 tonne per anchor or more.
Also, it is difficult to mount an i-beam as shown without drilling diagonally. Perhaps consider adding top plates that are wider than the section so the holes can be drilled vertically.

So much of THIS.

No offense but I would question the expertise of somebody who would think that it is appropriate to size up the anchors based on the monorail LOAD/6 when it is configured as the diagram shows. What load path could ever load those bolts equally!? Even LOAD/2 needs to be considered with respect to prying and lateral load.