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goal post truss weight loadings

#1 User is offline   brownie 

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Posted 12 February 2009 - 08:21 PM

Hi All
Help required!,
my minds thrown a blank, when using a truss on a pair of wind-up stands, how is the total weight loading calculated?

for example...

8m span of truss, supported on a pair of wind ups, each windup is capable of max loading of 180KG (assuming an evenly distributed load)

Thanks

#2 User is offline   tokm 

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Posted 13 February 2009 - 01:41 AM

Look at the load figures for the truss your using. It will say what the UDL (as well as CPL, TPL, etc..) is @ 8m.. Or at least it should do!

That's the figure to go off, obviously if this is more than the capacity of the stands, or in fact the other way around, well.. you work to the lower rating.

T

#3 User is offline   j_b 

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Posted 13 February 2009 - 12:00 PM

Don't forget the weight of the 8m of truss itself!

Not to mention the consequences of one of the stands being strapped to a speaker stack and tied in the middle to the false ceiling to stop it sagging, and someone 'dancing into' one of the speaker stacks.

#4 User is offline   tokm 

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Posted 15 February 2009 - 08:22 PM

Quote

Don't forget the weight of the 8m of truss itself!
IIRC, most loading spec's include the weight of the spans themselves in the calc's for what UDL/CPL you can apply to the truss, so this isn't usually an issue.

I'm sure there's some that don't, so check on any paperwork to see if it mentions the spans own weight.. if not speak to the truss manufacturer!

T

#5 User is offline   Boggy 

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Posted 17 February 2009 - 01:31 AM

I would have thought that the weight of the truss was important when checking that the capacity of the windups is not exceeded.
Boggy,
From Australia

#6 User is offline   AndyJones 

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Posted 17 February 2009 - 03:28 AM

Also take into account the cabling you are putting onto the truss allowing a certain percentage extra on one stand allowing for the cable drop on one end.

AndyJones
Andy Jones | Zeal Events
www.ZealEvents.com
Andy.Jones@ZealEvents.com

#7 User is offline   Stuart91 

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Posted 17 February 2009 - 07:51 PM

View PostBoggy, on 17 Feb 2009, 1:31 AM, said:

I would have thought that the weight of the truss was important when checking that the capacity of the windups is not exceeded.


The other thing to look out for is that if it is wound up unevenly there can be significantly more weight placed on one of the stands.
I'm selling some bargain priced LED parcans, also still got some Trilite truss junctions available.

#8 User is offline   sleah 

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Posted 17 February 2009 - 08:07 PM

View Postj_b, on 13 Feb 2009, 12:00 PM, said:

Don't forget the weight of the 8m of truss itself!

Not to mention the consequences of one of the stands being strapped to a speaker stack and tied in the middle to the false ceiling to stop it sagging, and someone 'dancing into' one of the speaker stacks.



View Posttokm, on 15 Feb 2009, 8:22 PM, said:

Quote

Don't forget the weight of the 8m of truss itself!
IIRC, most loading spec's include the weight of the spans themselves in the calc's for what UDL/CPL you can apply to the truss, so this isn't usually an issue.

I'm sure there's some that don't, so check on any paperwork to see if it mentions the spans own weight.. if not speak to the truss manufacturer!

T


I think j_b meant when calculating the loading of the wind up stands, in which case you do need to factor in the weight of the actual truss.
Simon Leah

Grumpy Old Man

#9 User is offline   Tobydare 

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Posted 19 February 2009 - 01:43 PM

Given that you are inside and on an even floor, you need to add up the weight of all your componants, and dveide evenly over the two stands. however you probebly need to offset the loading to one side to allow for the cable coming off on one end andallow for the weight of the cable drop.

If in doors make sure that the height of the structure is no more that three times the smallest dimension of the footprint of the stands. The more weight you add the more top heavy the overall structure can become. This can be rectified by adding weight to the bottom of the stands, which is probbly not a bad idea anyway.

#10 User is offline   j_b 

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Posted 27 February 2009 - 11:23 AM

View PostTobydare, on 19 Feb 2009, 1:43 PM, said:

If in doors make sure that the height of the structure is no more that three times the smallest dimension of the footprint of the stands.


So, you wouldn't wind a typical manfrotto stand up then?

#11 User is offline   Seano 

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Posted 27 February 2009 - 12:25 PM

View Postj_b, on 27 Feb 2009, 11:23 AM, said:

So, you wouldn't wind a typical manfrotto stand up then?

I don't think they make one, but perhaps you can enlighten me: which stand in Manfrotto's range has a max height greater than 3x the max width of its base?

#12 User is offline   Duncan Wood 

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Posted 27 February 2009 - 03:42 PM

View PostSeano, on 27 Feb 2009, 12:25 PM, said:

View Postj_b, on 27 Feb 2009, 11:23 AM, said:

So, you wouldn't wind a typical manfrotto stand up then?

I don't think they make one, but perhaps you can enlighten me: which stand in Manfrotto's range has a max height greater than 3x the max width of its base?


Type 19, Type 40 etc.
Or from others Supertower's go 4:1, & if you're being anal a Doughty Zeniths over 3:1

#13 User is offline   LampTramp 

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Posted 19 March 2009 - 01:35 AM

If your using Prolyte truss get their product book and all the loading tables are in it!!!! start there me thinks
on a 9 meter lenth of H30v you can get around 199Kgs but an 8 meter span on 2 stands.........your looking at 80+Kgs for the truss before loading....
Look at the truss manufactuer and their loading charts........
If all the world's a stage..I want better lighting!

#14 User is offline   david.elsbury 

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Posted 19 March 2009 - 06:56 AM

Lamptramp, you're a month behind. Look at the dates....
David Elsbury
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"Technician like ninja... live in shadow... move in silence"

#15 User is offline   LampTramp 

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Posted 21 March 2009 - 10:37 AM

Oh yeah!! opps
If all the world's a stage..I want better lighting!

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