4 ms·

Structural engineers are weird. They want to be able to guarantee that a structure can withstand a certain load. Eg. They'll calculate the maximum load the floo

Structural engineers are weird. They want to be able to guarantee that a structure can withstand a certain load. Eg. They'll calculate the maximum load the floors will take (eg. if its an office and filled with filing cabinets) and then multiply that by a safety factor of 10 and design the structure to support that, at the very least. They'll probably make it even stronger so the structure never even flexes (which is not unsafe but it can just unsettle people) The goal is, it is impossible for this structure to fail under any likely conditions, so eg. any kind of wind load thats been experienced in so many decades.

DrPhish 8y ago
We do this with dimension lumber. There are a couple of different processes of assessing the strength of a piece of lumber, but the designation is MSR (Machine Stress Rated) "is intended for any engineered application where low variability in strength and stiffness properties is primary product consideration" (1). It looks like there have been attempts to do the same thing with bamboo, starting with adapting existing lumber grading machinery (2) I don't see why it would be impossible to use bamboo in engineering applications as long as the physical properties of a given grade of bamboo stock could be guaranteed. I assume treatment for pests, rot and fungus would also need to be applied to guarantee that those properties remain inviolate, but am no expert on bamboo. (1) - https://www.wwpa.org/western-lumber/structural-lumber/machine-stress-rated-(msr) https://www.wwpa.org/western-lumber/structural-lumber/machin... (2) - https://www.researchgate.net/publication/313531323_Grading_of_Bamboo https://www.researchgate.net/publication/313531323_Grading_o...
greggyb 8y ago
How is this incompatible with a product that comes with minimum guarantees? Say we have a way to grade bamboo (this is the question mark in my argument). Grade X bamboo would support the floor in question. Grade 10X bamboo would support 10x the floor in question. For the floor in question, use Grade 10x bamboo. I mean, it seems like something similar must be going on in structural lumber. Take 2x4s for example. This is one piece of wood out of a tree. There must be natural variation across the population of trees providing wood for these. How do we handle that except by saying that this piece of lumber meets minimum guarantees but may be stronger than that minimum, and is statistically likely to exceed the minimum.

DrPhish 8y ago

We do this with dimension lumber. There are a couple of different processes of assessing the strength of a piece of lumber, but the designation is MSR (Machine Stress Rated) "is intended for any engineered application where low variability in strength and stiffness properties is primary product consideration" (1). It looks like there have been attempts to do the same thing with bamboo, starting with adapting existing lumber grading machinery (2) I don't see why it would be impossible to use bamboo in engineering applications as long as the physical properties of a given grade of bamboo stock could be guaranteed. I assume treatment for pests, rot and fungus would also need to be applied to guarantee that those properties remain inviolate, but am no expert on bamboo. (1) - https://www.wwpa.org/western-lumber/structural-lumber/machine-stress-rated-(msr) https://www.wwpa.org/western-lumber/structural-lumber/machin... (2) - https://www.researchgate.net/publication/313531323_Grading_of_Bamboo https://www.researchgate.net/publication/313531323_Grading_o...

greggyb 8y ago

How is this incompatible with a product that comes with minimum guarantees? Say we have a way to grade bamboo (this is the question mark in my argument). Grade X bamboo would support the floor in question. Grade 10X bamboo would support 10x the floor in question. For the floor in question, use Grade 10x bamboo. I mean, it seems like something similar must be going on in structural lumber. Take 2x4s for example. This is one piece of wood out of a tree. There must be natural variation across the population of trees providing wood for these. How do we handle that except by saying that this piece of lumber meets minimum guarantees but may be stronger than that minimum, and is statistically likely to exceed the minimum.