450 Beams (1 Viewer)

AshReactive

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Gents and unlikely ladies,

Can anybody find any reference to 450 Alloy beams in TG20:13.

I had a quick gander through a clients and whilst there seems to be more in the way of technical data and Technical Pictionary there seems to be less in the way of the most common beam in use.

I did however notice a section in the first book that gave an example for ladder beams and unit beams, which stated as long as the capacity was greater than the stated the beam was fair to use, problem i see with that is the 450 beam falls in the lower category with a bending capacity or 12.5knm to 29.1knm meaning that the 450 beam can only be used for supporting 2 bay spans.

I'd like to confirm this is not a complaint or anything, i'm just making sure i have understood the guidance as everyone else has.

Also will this mean that any span greater than 4m with a 450 beam will have to be designed?

Also does anybody actually specify 610 unit beams anymore?
 
Still use unit beams on some jobs. Depends on the job and the client.

I would have thought the document should point to you towards the manufacturers specs for the alloy beams rather than trying to compare them to "generic" ladder/unit beams.
 
At the previous round of NASC meetings, the demonstration version of the eguide showed the shear and bending values of the 2 and 3 bay bridges dependent on the number of lifts above them so you could check if a particular type of ali beam was ok to use, such as a 450 beam in a single lift 3 bay bridge.

This doesn't seem to have made it into the final version of the eguide so it will be necessary to do a design for anything outside of a 2 bay ladder / 450 beam bridge, or 3 bay unit / 750 beam bridge.
 
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