tensile strength tube

hi all, great site, im new , and just saw this thread, and would like to ask if the maximum load on the standard is dictated by the lifts heights - such has -1.5m or 2m lift heights? etc.
 
worldwidescaff said:
hi all, great site, im new , and just saw this thread, and would like to ask if the maximum load on the standard is dictated by the lifts heights - such has -1.5m or 2m lift heights? etc.
Click to expand...

Hi Worldwidescaff
I'm sure the max load on a standard is dictated by the tie points
 
World,

Partly..

The axial load capacity of a standard is dependant upon its effective length (when assessing it using TG20:08). Effective length of the standard is defined as the length between points of effective lateral restraint (e.g. nodes, ties, braces etc)

What actually constitutes a 'point of restraint' is up for debate...

Anyway, the best place to look is TG20, if you start reading at page 139 section 39.7 and read to the end of page 143 that will help explain things.

Note: TG20 is based on permissible stress analysis method and uses a system of effective lengths to simplify the procedure for calculating axial load capacity. This is the way it has been done in the UK since 5973 was first introduced. Its not the only way by any means, but is the most common here.
 
Thanks jakdan,

---------- Post added at 02:11 PM ---------- Previous post was at 01:19 PM ----------

if the table says - that the s.w.l of the standard is 30kn fixed at 2m centres.

is this saying the standard has a S.W.L of 30kn on every 2 lift or is the S.W.L of the standard 30kN in total from top to bottom providing it is supported every at 2m centers?

thanks guys
 
WWS,

The safe working load of BS 1139 tube (as this still most common, not EN39) with a 2000mm effective length is 28.2kN.

That is total load, NOT per lift. The cumulative load in the bottom lift say, from all those above must not exceed this figure.

If using TG20 be careful when calculating the effective length. You have to specifically justify effective length if you are not going to take the vertical tie interval as the determining factor.

Consider also the worst case is often not just the lift height but also includes a consideration of the bit of standard forming the kicker. It is seen as a cantilevered projection down from the first lift. The best explanation of this is on page 238: Appendix D.

B.
 
morning ben, wots the turn around time for a set of drawings at the moment
 
I like your understanding and explanation . I work with two boys who would not know compressive strength if it sat on them,
 
Would you class a transom on doubles a restraint or just the tie spacing? And if the ties are on the braced pair of standards what would he effective length be on the unbraced standard?
 
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