450ml alloy beam calcs.

Anyone got the loadings to hand for 450 alloy beams,some graduate as drawn them in as steel ladder beams,as its for use as a checker under an existing lift i am argueing that these alloys will suffice as the loadings are the same,how do they compare?steel v alloy?

---------- Post added at 06:47 PM ---------- Previous post was at 05:29 PM ----------

surely some of the designers on here know the loadings of steel v alloy

bigfish said:

Anyone got the loadings to hand for 450 alloy beams,some graduate as drawn them in as steel ladder beams,as its for use as a checker under an existing lift i am argueing that these alloys will suffice as the loadings are the same,how do they compare?steel v alloy?

---------- Post added at 06:47 PM ---------- Previous post was at 05:29 PM ----------

surely some of the designers on here know the loadings of steel v alloy

Click to expand...

be patient bigfish, them boys only work mon- fri 9 till 5:laugh:

you could move the post to the design thread? they're that daft they only look for the one heading

bigfish said:

Anyone got the loadings to hand for 450 alloy beams,some graduate as drawn them in as steel ladder beams,as its for use as a checker under an existing lift i am argueing that these alloys will suffice as the loadings are the same,how do they compare?steel v alloy?

---------- Post added at 06:47 PM ---------- Previous post was at 05:29 PM ----------

surely some of the designers on here know the loadings of steel v alloy

Click to expand...

I am NO designer.
But i have a rare quality that most designers lack... common sense.

Im almost certain that Alloy beams are as strong, if not stronger than Steel ones.
But, without the calcs, i cant say for 110% certain.
Id pick Alloy over Steel anyday and not just because they are lighter.

99% coz they are light and 1% because they are silver in colour, lol.

alloy beams r stronger than steel just dont know the calcs

All depends on the type of 450mm beam, and the application it is being used for - they are usually stronger in bending than a steel ladder beam, but weaker in shear. Often in instances with large loads over short spans, ladder beams will be specified because of this shear capacity.

If the engineer has shown ladder beams, you will need confirmation from him to substitute them for anything else.

i cant believe i am agreeing with Mark

OK the hook was in the water and I have bitten,
Mark is indeed correct in his statement not all 450's are the same strength but most are around equivalent to a ladder beam in bending. Shear as Mark has said is a different matter.
An Engineer would need more information on the beams being supplied before he could commit to the change.
If possible most Engineers would specify the alloy beams, unless they meet a scaff who give them gyp then the old adage of “if in doubt double it” comes into play.:blink1:

Stay lucky guys
regards
Alan

Call them lattice beams and this may help your eng.

Tension force in the spigot connection is 39kN, on average.

Load capacities do vary dependent on manufacturer, but are on average, 10 ftspan, point load 13 kN, UDL 5 kN when top chord is braced at 4 ft centres.

20 ft span , point 6kN, UDL 1.4 kN at 4 ft centres on top chord braced, bottom chord at 7 ft centres, section brace the same.

Or just pay a proper eng, and pass it on to client.

Celtic

I did pay a proper designer,but this firm have their own engineer who checks the design and then signs them off as fit for purpose,but he keeps making amendments which are making the job unworkable:wondering:

Bigfish,

We have a layher technical document on their beams, pm me with your email address and i will forward it onto you for your designer to use.

Celtic

Morning Bigfish
For the disbelievers amongst you it is 05:30 Sunday Morning and yes I have been at work for an hour.
Sorry Celtic, lattice beam covers a wide variety of beam from 450 to 750 deep in both steel and Alloy. I would not recommend you work to an average beam capacity as the quality and capacity will depend upon the supplier but the Engineer should be working to give you the best result which will entail the beam working to capacity.
For information purposes only:
A Haki 450 Has a BM of 15.7kNm with Permissible shear of 12.7kN
A Ladder beam has a BM of 13.5kNm with a Permissible shear of 18kN
As stated in earlier posts it’s not all about bending.

Hard choices…. Design
A scaffold design is prepared for “The Scaffold Contractors” use in the erection of the structure.
You have supplied the drawing to the client as an indication of what you intend to build and “take responsibility” for. The client is responsible for ensuring it is suited to the purpose i.e. it is on the right building and gives suitable access, cover etc.
Provided you are content your Designer/Engineer has carried out his task adequately and in accordance with the relevant codes and manufacturers guidelines (no cock ups) you are within your rights to advise your client that he will need to pay any additional costs for both the design work and the additional input to the structure.
You should also be advising your client that you will now be erecting the structure to “His Design” and as such responsibility for the design will be his.

Why is that hard choices?
Because he may well tell you to pack up and move on.
Your choice is to stand your ground or to do as your client asks.
regards
Alan

Bigfish

I have technical date sheet for 450mm Haki beams for various lenghts of beams ,ie 4.0m , to 12.0m should you require it pm me your e-mail address and i will forward on to you and anyone else who would like a copy .