As a Civil Engineer, I often hear people blame concrete cracking and failure on inadequate strength. In my 40 years of experience it has always happened due to poor joint detail which in turn causes stresses from inadequate allowance for expansion, not strength issues.
I've seen concrete-layers who have been in the trade for years spend so much time and effort in producing a nicely finished surface, but have neglected to put in adequate expansion-strips, so within a year there's cracks or spalling in the slab!
Great video! Another consideration when looking at temperature effects on a structure is when there is a significant thermal gradient through the thickness of the beam--where one side is expanding more than the other side. Not as common with steel beams where the thermal conductivity is high, but can be a problem with concrete or wood beams.
I've seen concrete-layers who have been in the trade for years spend so much time and effort in producing a nicely finished surface, but have neglected to put in adequate expansion-strips, so within a year there's cracks or spalling in the slab!
Length change in wood due to moisture absorption is greater than that due to an increase in heat? Really? I'm surprised. I expect significant changes dimension across the grain, due to moisture level but significant changes in dimension measured with the grain, due to moisture absorption, I thought would be near to zero. It would be interesting to know the linear change (with the grain) of heat vs moisture.
ruclips.net/video/UXQugQPSLmA/видео.html Rails for the 300kph TVG in France are made in 300 meter lengths and welded together with aluminum. What keeps them from buckling? ruclips.net/video/UXQugQPSLmA/видео.html According to the documentary the solution is to use 'very heavy rails weighing 60kg per meter so they won't lift'. What am I missing?
@GeeKayKayGee I don't know of the specific case of TVG in France but I believe some train tracks are pre-stressed, like heated up to a high temperature before they are laid out and being safely secured. Then when the track heats up by intense summer sun the already built-in compressive stress will just be reduced instead of the tracks buckling. Pre-stretching the tracks when they are laid out should have the same effect. It is similar to a pre-stressed concrete element which is designed with compression stresses.
Hello, could you please post a lecture vedio about hygroscopic expansion coefficients (Beta) for the case of cement that is internally cured in a soil (oil well case) and how chemical shrinkage occurs due to curing process with respect of Temperature and Moisture and how thermal stress work for 3-D when the cement is poured in between rock formation and steel casing (constrained) in the oil well?
Thank you for the video. I am always so amazed how many variables Engineers have to include to build a structure. It's amazing that anything stays standing.
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As a Civil Engineer, I often hear people blame concrete cracking and failure on inadequate strength. In my 40 years of experience it has always happened due to poor joint detail which in turn causes stresses from inadequate allowance for expansion, not strength issues.
I've seen concrete-layers who have been in the trade for years spend so much time and effort in producing a nicely finished surface, but have neglected to put in adequate expansion-strips, so within a year there's cracks or spalling in the slab!
@@stevie-ray2020 Inadequate or badly placed.
@@gregessex1851 I've seen cases of both, but it's usually large areas concreted with little or no expansion-strips at all!
Great video! Another consideration when looking at temperature effects on a structure is when there is a significant thermal gradient through the thickness of the beam--where one side is expanding more than the other side. Not as common with steel beams where the thermal conductivity is high, but can be a problem with concrete or wood beams.
I really enjoyed this one. And yes please make a video on moisture expansion.
love your videos on explaining the concept and appreciate a follow up video on how to solve the problem!!
Absolutely, a video on wood and moisture causing expansion.
Hey nice audio, glad you improved it over time!
I've seen concrete-layers who have been in the trade for years spend so much time and effort in producing a nicely finished surface, but have neglected to put in adequate expansion-strips, so within a year there's cracks or spalling in the slab!
def interested in wood & moisture, and how people mitigate moisture intrusion if they are restricted to using wood as structural material
Cool videos!
These videos are amazing
I would love to see a video on wood vs moisture!
Interesting video! Would be nice to have a more detailed follow-up video on countermeasures.
I would like to see how Roman concrete differs as modern concrete has a 100 year life and Roman concrete is still solid.
Length change in wood due to moisture absorption is greater than that due to an increase in heat? Really? I'm surprised. I expect significant changes dimension across the grain, due to moisture level but significant changes in dimension measured with the grain, due to moisture absorption, I thought would be near to zero. It would be interesting to know the linear change (with the grain) of heat vs moisture.
My favorite subject is hipars hyperbolic parabala which is the most efficient ie strength per material shape
ruclips.net/video/UXQugQPSLmA/видео.html
Rails for the 300kph TVG in France are made in 300 meter lengths and welded together with aluminum. What keeps them from buckling?
ruclips.net/video/UXQugQPSLmA/видео.html According to the documentary the solution is to use 'very heavy rails weighing 60kg per meter so they won't lift'.
What am I missing?
@GeeKayKayGee
I don't know of the specific case of TVG in France but I believe some train tracks are pre-stressed, like heated up to a high temperature before they are laid out and being safely secured. Then when the track heats up by intense summer sun the already built-in compressive stress will just be reduced instead of the tracks buckling. Pre-stretching the tracks when they are laid out should have the same effect.
It is similar to a pre-stressed concrete element which is designed with compression stresses.
Hello,
could you please post a lecture vedio about hygroscopic expansion coefficients (Beta) for the case of cement that is internally cured in a soil (oil well case) and how chemical shrinkage occurs due to curing process with respect of Temperature and Moisture and how thermal stress work for 3-D when the cement is poured in between rock formation and steel casing (constrained) in the oil well?
Chemincal explansion Joints
anything without an expansion joint is susceptible. need not be in the sun. a heated tile floor in a basement can do the same.
Agreed. Thanks for the comment. How did you find this video? It doesn't premiere for 2 hours still! (Except for to you apparently, hah!)
@@TheEngineeringHub the algorithm works in mysterious ways lol. it was set as will premier in x hrs
The answer is: "Hardly"!
Those railtracks show they were not installed properly, they either have no expansion joints or were installed by incompetent workmen.
Thousands of an inch,inch’s,feet,yards,miles.
Thank you for the video. I am always so amazed how many variables Engineers have to include to build a structure. It's amazing that anything stays standing.
0:42 Do materials stretch the same at different temperatures?
Is it the same between -15/-10 and +25/30 because dL=5 in both?
This is the nerd content I need. Keep em coming and please explain the role of water in thermal stresses in a future video.
Thank you!
Excellent content 👌