So are you saying that 2 scaffold boards can be used instead of a Catnic woody?I've gone cross eyed.
Ideally yes, otherwise it would be a trip hazard.So are you saying that 2 scaffold boards can be used instead of a Catnic woody?
Sometimes Woody its best to follow your mothers stock answer to inquisitive questions " because thats why" than try to understand the intricacies of what is being askedI've gone cross eyed.
All things being equal, strength & deflection have a cubic relationship to depth. So a 100x140 lintel is ~8 times stronger/stiffer than a single 100x65mm lintel. Whereas doubling them up (which is pretty much the same size and cost as the 100x140) is only twice as strong/stiff.Interesting conclusion, if I had a lintel that was taking a load y then the deflection would be 10mm( say) if I halved the load the deflection would be 5mm. I then take the load away and place a similar lintel underneath the original one and reapply the load y. The top lintel deflects as does the bottom one in equal measure. When the top lintel has deflected 5mm it will be resisting a load of y/2, similarly the bottom one will be resisting a load of y/2 hence the total load resisted will be y. Taking this through to a deflection of 10mm then each lintel will be resisting a force of y giving a total resisting force of 2y. The lintel weights are ignored for this simplification. To me it is the same as put a scaffolding plank on top of another which makes things less bouncy which reflects the decrease in loading per board. Obviously a single lintel of twice the depth increases the available resisting force more than 2 laid together. Thoughts?
What?Sometimes Woody its best to follow your mothers stock answer to inquisitive questions " because thats why" than try to understand the intricacies of what is being asked
I think it's quite simple.All things being equal, strength & deflection have a cubic relationship to depth. So a 100x140 lintel is ~8 times stronger/stiffer than a single 100x65mm lintel. Whereas doubling them up (which is pretty much the same size and cost as the 100x140) is only twice as strong/stiff.
So I was being pessimistic saying it'd only be load distribution, but you are relying on the mortar bed giving a good load transfer between them. If the load was too much for a single 65mm, I'm not aware of any manufacturer who'd instruct you to stack up as opposed to just using a larger lintel.
Totally agree but it doesn't matter if there is a mortar bed or not, the load will still be transferred by numerous contact points between the upper and lower lintel.All things being equal, strength & deflection have a cubic relationship to depth. So a 100x140 lintel is ~8 times stronger/stiffer than a single 100x65mm lintel. Whereas doubling them up (which is pretty much the same size and cost as the 100x140) is only twice as strong/stiff.
So I was being pessimistic saying it'd only be load distribution, but you are relying on the mortar bed giving a good load transfer between them. If the load was too much for a single 65mm, I'm not aware of any manufacturer who'd instruct you to stack up as opposed to just using a larger lintel.
Sorry Woody I didn't know you had a cold and square eyes, hope you do find the causeWhat?
But sitting in front of the TV did not give me square eyes, and I did not catch a cold by not wearing my big coat when I went outside.
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