Trilight Apex

[Dazzler]

Thanks for the replies. I just want to read them so I have a point of reference really, it's always good to have vague idea of what people are talking about when you're discussing the rigging of a show.

 

Dazzler

[andy_s]

I'll endorse the above comments - both books are well worth reading, although there is a bit of dupilcation between them - I guess Mr Higgs has to assume that some readers won't have read both.

 

There's also a book called "structural design for the stage" (I think - the book is in the office) which has a pretty informative about truss design in a general way, and about other structural engineering as well.

[Russ247]

To be honest Trilite is a very light duty truss so there is probably little diff apex up or down but I would recommend apex up if any weight is hung as it does need to be shared across the chords so 1 light upstage & 1 downstage etc. The importartant thing to remember with the spec sheets is to read the small print! The Trilite one states this is for a single span i.e. an 8m span is made of 1 x 8m piece not 4 x 2m sections. It is weakened a lot by connections. Comfort should not really come into it, I wouldn't recommend climbing around on a lot of it anyway.

Apex side usage is mostly used for screen surrounds as is more pleasing to the eye & negates the need for goalpost corners (apex on the inside of the corner). They have lots of variations of corners (apex up, down, side etc) as it is more for architectural usage rather than substantial weight. Hope this helps!

 

Good to see some familiar faces (colin monk & chris higgs)

Chris' books are a very good read & very informative. Have asked his advice on many a project when doing something odd as he knows his stuff.

 

All the best

Russ

[gil-galad]

I think it would be more beneficial if we don't talk about tension, compression, torsion and all the other forces than can be on a truss. Instead her are some handy notes.

 

1. Read the maunfacturers documentation.

 

2. If your triangle truss is apex up then both cords should ideally be evenly loaded within the manufacturers recommendations.

 

3. If your triangle truss is apex down then you have only one cord and life is easier as long as you keep within the manufacturers recommendations.

 

4. If your triangle truss is apex in/out then it is effectively a ladder truss and the load capacity of the truss will be reduced and you should seek approval from the manufacturer first with load data to cover the use.

 

 

The mathematics involved with the forces in truss are complicated. Manufacturers give guidance notes and load data sheets to make life easier.

 

If you want to learn more about trussing then Peter Hinds book about Aluminium structures is very good and give all the theory about forces in trusses.