Hanging platform to structural beam connection
Hanging platform to structural beam connection
(OP)
I am looking at adding a work platform for some control valves at one of our facilities. After several iterations, I am going with a hanging platform that is supported by existing structural steel roof beams. This appears to be the best solution based on congestion in the area. That said, I am undecided on welding the vertical supports or using a bolted connection to attach the vertical supports to the W12/W16. The vertical supports are W6 beams that I plan to attach to the bottom flange of the existing beams. Most of the reference material I have covers beam to beam connections using the web and then beam to column connections using the flanges. Anyone have any insight or advice for this particular application.










RE: Hanging platform to structural beam connection
In addition to this, you need to:
RE: Hanging platform to structural beam connection
Appreciate the response:
1: I have the original drawings and plan to review loading in more detail. The main beams (W30x108) carry the roof load. There is a packaged cooling tower on the roof which sits on the W16s. My initial review shows that there should be no issue with the additional loading.
2. Already verified. Deflection and stress are well within safe limits. These platforms are each ~ 6 sq feet. They are for a single I&C tech to work on the actuators. Actual load is very low.
3. Currently plan to use .625" bolts for connections.
4. I plan to include some diagonals for bracing, but they are not reflected in my model yet.
RE: Hanging platform to structural beam connection
RE: Hanging platform to structural beam connection
RE: Hanging platform to structural beam connection
RE: Hanging platform to structural beam connection
You'd generally use a piece of a WT and bolt (on gauge) with the bottom flange above. Prying action would need to be checked. (AISC's manual has equations for that.)
RE: Hanging platform to structural beam connection
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Hanging platform to structural beam connection
RE: Hanging platform to structural beam connection
Hmm, can't say I have seen those in practice. Any manufacturers you know of that provide something for this application?
Edit: Looks like Kee Klamp (or an affiliated company) have something that might work. They offer BeamClamp BL Flange Clamp. Need to do some research on this option.
RE: Hanging platform to structural beam connection
I think Lindapter still does. Their website: http://www.lindapter.com/
And that is a good point hokie raises: whatever you do, be sure the manufacturer allows it in that area. I've worked with people where you can't do any cutting in certain areas (let alone welding).
RE: Hanging platform to structural beam connection
RE: Hanging platform to structural beam connection
RE: Hanging platform to structural beam connection
Look at a few of the pictures for this one.
http://www.lindapter.com/Products/Girder_Clamp/1/T...
It makes me slightly nervous, but would also be wonderful to have a rated item that can be used in this application for low load supports for piping or electrical utilities.
RE: Hanging platform to structural beam connection
RE: Hanging platform to structural beam connection
Depending on the type of flexibility you want to have in your piping you should probably go with clipped connections such as what KootK recommended, Since you don't want to create eccentric forces on your roof beams. Usually allow flexibility in the lateral directions while theoretically only supporting the pipe vertically. For DETstru's solution you can use some lifting lug analyses for this type of situation.
If you use clips that Warose helped you out with you are going to have to detail it pretty good because it would require a funky plate size. I wouldn't do it honestly in that situation. I've seen railroad beams tied down with those types of clips but the beams have a very stiff surface to bear on.
Industry standard - PIP - Galvanized A325 bolts. Also use more than one bolt per faying surface. OSHA and AISC both specify atleast 2 bolts for all steel to steel connections. Also, Consider overhead welding being difficult and expensive. The minimum center to center distance between bolt holes is 2.67*nominal diameter. Also, make sure you do a tension and block analysis on the connection. Check your bolt strength for a 5/8" diameter bolt. If you are using modeling software make sure you set supports as pinned.
RE: Hanging platform to structural beam connection
These platforms will not connect to or support piping in any way. They are only for a technician to work from when servicing the control valves. Due to the congested area, we are spending $8,000 plus on scaffolding every time they need service.
RE: Hanging platform to structural beam connection
RE: Hanging platform to structural beam connection
1. Use welded lugs in accordance with DETstru's suggestion. Specify that attaching the lugs be performed by a welder certified for structural overhead welding.
2. For the overhead welding, require continuous inspection per Nor Cal SE's suggestion.
3. Design each (6 ft2?) platform for live load of at least 1000 lb. or 100 lb/ft2, whichever is greater.
4. Design each of the (4?) hangers supporting a platform to support far more than 1/4 of the total load.
Don't want to send unsuspecting workers (fellow employees, in my case) onto a suspended platform... with their (heavy) tools... and perhaps (heavy) replacement valves, etc. This is not a time for a "minimum" or "cheap" design.
www.SlideRuleEra.net
www.VacuumTubeEra.net
RE: Hanging platform to structural beam connection
3. I used 1000 pounds for my design load.
4. Each hanger (5 total) is capable of supporting significantly more than 1/4 load. I put a lot of safety factor into any platform I design. I keep stresses and deflections very low (since I know that maintenance guys will inevitably use these platforms for more than what the should have been designed for). Usually I target a single support being capable of the carrying the entire load.
That said, I looked at the loading on the roof beams in more detail and it is a little closer than I like. I am currently evaluating supporting it from the floor and may go that route instead ( it will end up cantilevered, but should be a safer overall design).
RE: Hanging platform to structural beam connection
IMHO, hanging platforms are to be avoided unless absolutely essential.
www.SlideRuleEra.net
www.VacuumTubeEra.net
RE: Hanging platform to structural beam connection