Well he is right. Structural glass is "stronger" than concrete (based on mechanics of materials) since its modulus of elasticity is higher than that of concrete. . However, each material suffer weakness some how. In concrete, it is tensile strength (this is why concrete is reinforced with steel). In glass, it is imperfections in the material itself that causes stress concentration at loads close to failure. Furthermore, glass is brittle material.
About 9 years ago I met the structural engineer who designs Apple stores glass structures in a conference about transparency in tall buildings. He told amazing things about the glass as structural material. Long story short, the structure is well designed and will perform as well as any other building in earthquake or during high winds.
Well, he isn't right. Neither are you. Especially based on the mechanics of materials. In your instance, I am correcting you respectfully because you are generally respectful.
First of all, we cannot use a single parameter to compare their "strength". Some will, again, accuse me of spouting tripe. But if we are invoking mechanics of materials, we should do it correctly. Second, Young's modulus is a measure of stiffness. In a general context, it may seem intuitive to believe that stiffness is strength. But is it that simple in the context of the durability of a building? Furthermore, what is the Young's modulus for glass? What is it for concrete? That's like asking how tall are buildings? And which direction are you measuring Young's modulus in? Like the perceived brightness of the sun, direction matters.
And we haven't even gotten into yield strength, tensile strength, compressive strength, fatigue, impact ... There is a reason the field is called mechanics of materials and not simply strength of materials.
I am going to resist sneering at your mention of meeting the dude who designed the glass structures at Apple. And again I mean that respectfully. Why do people mention these things? I went to a WHO concert, but I'd never tell anyone how to play a guitar. I saw Michael Jackson but still don't have a sense of rhythm.
There is no single structural engineer who designs Apple stores. If you met the guy who gets the credit, then you probably met James O'Callaghan. But I doubt he would say "he" designed the glass structures at Apple Stores. At least, I hope he didn't say it that way. For sure, if he heard you say that he told you, "structural glass is stronger than concrete." He'd ask you to stop because that would be a careless and incorrect generalization. I am no O'Callaghan but, for your sake, I suggest you stop repeating the same generalization, and respect the complexity of engineering. What engineers can do with glass is remarkable. But advances in concrete is no less so. In fact, you'd be amazed what happens when the two are mixed.
Finally, if you are so sure structural glass is stronger than concrete, please take a picture next time you are in a skyskraper where all the load bearing columns are made of glass alone. And if you really believe glass is stronger than steel, please take a video next time you see a construction crew drive glass piles into the ground to support a new building or bridge. Please wear safety glasses when you do this
Well, he isn't right. Neither are you. Especially based on the mechanics of materials. In your instance, I am correcting you respectfully because you are generally respectful.
First of all, we cannot use a single parameter to compare their "strength". Some will, again, accuse me of spouting tripe. But if we are invoking mechanics of materials, we should do it correctly. Second, Young's modulus is a measure of stiffness. In a general context, it may seem intuitive to believe that stiffness is strength. But is it that simple in the context of the durability of a building? Furthermore, what is the Young's modulus for glass? What is it for concrete? That's like asking how tall are buildings? And which direction are you measuring Young's modulus in? Like the perceived brightness of the sun, direction matters.
And we haven't even gotten into yield strength, tensile strength, compressive strength, fatigue, impact ... There is a reason the field is called mechanics of materials and not simply strength of materials.
Sure and this is why I said "However, each material suffer weakness some how...". By the way, mechanics of materials and strength of materials are the same subject. It just that some call it strength and some call it mechanics.
I am going to resist sneering at your mention of meeting the dude who designed the glass structures at Apple. And again I mean that respectfully. Why do people mention these things? I went to a WHO concert, but I'd never tell anyone how to play a guitar. I saw Michael Jackson but still don't have a sense of rhythm.
If we were talking about music and WHO concert and your meeting has something to do about this discussion then sure, why not bring it up. We are here at public discussion forum where people share their knowledge and experiences.
There is no single structural engineer who designs Apple stores. If you met the guy who gets the credit, then you probably met James O'Callaghan.
It was Tim Macfarlane of Dewhurst Macfarlane and Partners. James O'Callaghan used to work for him before leaving to start his own business. He did not tell me HE designed Apple stores. He mentioned during his keynote that their office designed the NY Apple store among other projects. My conversation with him was about general engineering design issues.
For sure, if he heard you say that he told you, "structural glass is stronger than concrete." He'd ask you to stop because that would be a careless and incorrect generalization. I am no O'Callaghan but, for your sake, I suggest you stop repeating the same generalization, and respect the complexity of engineering.
Can you point to me where I said he told me "structural glass is stronger than concrete."? There is large number of research related to structural glass. It is even included in building codes. You can find all the information you need about properties of structural glass. I am not going to link to online resources (Wikipedia and others) here because as an engineer I don't use these resources professionally. But if you want you can.
What engineers can do with glass is remarkable. But advances in concrete is no less so. In fact, you'd be amazed what happens when the two are mixed.
I know all about concrete. My dissertation and funded research are related to concrete
Finally, if you are so sure structural glass is stronger than concrete, please take a picture next time you are in a skyskraper where all the load bearing columns are made of glass alone. And if you really believe glass is stronger than steel, please take a video next time you see a construction crew drive glass piles into the ground to support a new building or bridge. Please wear safety glasses when you do this
You are implying that I said since glass is stronger than concrete then glass is the ultimate material. I never said that. In fact if you read my post again you will notice that I said that glass have its flaws.
You are implying that I said since glass is stronger than concrete then glass is the ultimate material. I never said that. In fact if you read my post again you will notice that I said that glass have its flaws.
But it should not be said that structural glass is stronger than concrete ... period.
Quote:
Originally Posted by NasserAE
I know all about concrete. My dissertation and funded research are related to concrete
And I was on your thesis committee and voted to fail you because you used Young's modulus as the sole parameter to compare strength, and erroneously thought mechanics of materials is only about strength of materials. But seriously, how the hell do such declarations bring meaning to a discussion? Are you going to bring up your grandmother's credentials too? Did she mislead you about mechanics and strength of materials being the same thing? That's like saying the sky and clouds are the same thing.
Your arguments, such as this one, read like they're straight out of the Wikipedia page on mechanics of materials.
This just proof that you don't know about the subject and tried to use Wikipedia. But since my statement is right and you couldn't proof otherwise you accuse me of using Wikipedia as a source. Nice try.
Well, he isn't right. Neither are you. Especially based on the mechanics of materials. In your instance, I am correcting you respectfully because you are generally respectful.
First of all, we cannot use a single parameter to compare their "strength". Some will, again, accuse me of spouting tripe. But if we are invoking mechanics of materials, we should do it correctly. Second, Young's modulus is a measure of stiffness. In a general context, it may seem intuitive to believe that stiffness is strength. But is it that simple in the context of the durability of a building? Furthermore, what is the Young's modulus for glass? What is it for concrete? That's like asking how tall are buildings? And which direction are you measuring Young's modulus in? Like the perceived brightness of the sun, direction matters.
And we haven't even gotten into yield strength, tensile strength, compressive strength, fatigue, impact ... There is a reason the field is called mechanics of materials and not simply strength of materials.
I am going to resist sneering at your mention of meeting the dude who designed the glass structures at Apple. And again I mean that respectfully. Why do people mention these things? I went to a WHO concert, but I'd never tell anyone how to play a guitar. I saw Michael Jackson but still don't have a sense of rhythm.
There is no single structural engineer who designs Apple stores. If you met the guy who gets the credit, then you probably met James O'Callaghan. But I doubt he would say "he" designed the glass structures at Apple Stores. At least, I hope he didn't say it that way. For sure, if he heard you say that he told you, "structural glass is stronger than concrete." He'd ask you to stop because that would be a careless and incorrect generalization. I am no O'Callaghan but, for your sake, I suggest you stop repeating the same generalization, and respect the complexity of engineering. What engineers can do with glass is remarkable. But advances in concrete is no less so. In fact, you'd be amazed what happens when the two are mixed.
Finally, if you are so sure structural glass is stronger than concrete, please take a picture next time you are in a skyskraper where all the load bearing columns are made of glass alone. And if you really believe glass is stronger than steel, please take a video next time you see a construction crew drive glass piles into the ground to support a new building or bridge. Please wear safety glasses when you do this
@NasserAE: ; Making the generalization that glass, or any other material, is "stronger" that concrete is ludicrous without qualifying under what circumstances it is "stronger". Reinforced concrete relies on a specific recipe developed for that use and then multiple types of tests to prove the performance of the actual product used on site. (Cylinders are compressed to test the compressive strength, beams are broken to test the flexural strength, a slump cone is done to measure its workability before placing, the reinforcing steel is tested and graded before it is ever delivered. My point is that one would need to specify the actual grade of concrete required (usually specified by numbers of sacks of cement per yard, slump, additives, special aggregate, etc… but ultimately by its compressive and flexural strength at given times after placing and curing under same conditions (typically 7 and 28 days and less a quick set batch is called for). Similars types of standards would apply to structural glass used in a building (although delivered ready to place). I cannot speak to the specifics of the standards for describing the structural properties of glass but do know they exist (and vary widely depending on the formula for the glass and how it is produced).
Sure and this is why I said "However, each material suffer weakness some how...". By the way, mechanics of materials and strength of materials are the same subject. It just that some call it strength and some call it mechanics.
If we were talking about music and WHO concert and your meeting has something to do about this discussion then sure, why not bring it up. We are here at public discussion forum where people share their knowledge and experiences.
It was Tim Macfarlane of Dewhurst Macfarlane and Partners. James O'Callaghan used to work for him before leaving to start his own business. He did not tell me HE designed Apple stores. He mentioned during his keynote that their office designed the NY Apple store among other projects. My conversation with him was about general engineering design issues.
Can you point to me where I said he told me "structural glass is stronger than concrete."? There is large number of research related to structural glass. It is even included in building codes. You can find all the information you need about properties of structural glass. I am not going to link to online resources (Wikipedia and others) here because as an engineer I don't use these resources professionally. But if you want you can.
I know all about concrete. My dissertation and funded research are related to concrete
You are implying that I said since glass is stronger than concrete then glass is the ultimate material. I never said that. In fact if you read my post again you will notice that I said that glass have its flaws.
I guess he didn't realize he was replying to an engineer who actually is required to know this information to be able to do their jobs.
"Strict, but not necessarily good for surviving earth quakes. I know a geologist who was having a house built in an area where the bedrock was relatively close to the surface. He wanted to sink pylons down into the bedrock so that the house would be immune from the liquefaction that would occur if there was an earthquake."
I can't not comment on this. Your friend was building a house where the bedrock was close to the surface and he was afraid of liquifaction if an earthquake happened?? Uh, which is it? It can't be both. Liquifaction happens where there is filled land and weak soil types, *not* in areas close to bedrock.
And a comment about earthquake safety where there's a lot of glass: seismic codes are designed to minimize as much as possible loss if life and injury. A glass structure may seem dangerous, but the point is to design the structure so people aren't hurt or killed. This determines the kind of glass that's allowed. Think of a large store window or even a car windshield. The glass will break if damaged or broken, but won't cause injury. I'd rather be hit by pieces of falling safety glass than by a large beam, but no one worries about beams.
Comments
Quote:
Originally Posted by NasserAE
Well he is right. Structural glass is "stronger" than concrete (based on mechanics of materials) since its modulus of elasticity is higher than that of concrete. . However, each material suffer weakness some how. In concrete, it is tensile strength (this is why concrete is reinforced with steel). In glass, it is imperfections in the material itself that causes stress concentration at loads close to failure. Furthermore, glass is brittle material.
About 9 years ago I met the structural engineer who designs Apple stores glass structures in a conference about transparency in tall buildings. He told amazing things about the glass as structural material. Long story short, the structure is well designed and will perform as well as any other building in earthquake or during high winds.
Well, he isn't right. Neither are you. Especially based on the mechanics of materials. In your instance, I am correcting you respectfully because you are generally respectful.
First of all, we cannot use a single parameter to compare their "strength". Some will, again, accuse me of spouting tripe. But if we are invoking mechanics of materials, we should do it correctly. Second, Young's modulus is a measure of stiffness. In a general context, it may seem intuitive to believe that stiffness is strength. But is it that simple in the context of the durability of a building? Furthermore, what is the Young's modulus for glass? What is it for concrete? That's like asking how tall are buildings? And which direction are you measuring Young's modulus in? Like the perceived brightness of the sun, direction matters.
And we haven't even gotten into yield strength, tensile strength, compressive strength, fatigue, impact ... There is a reason the field is called mechanics of materials and not simply strength of materials.
I am going to resist sneering at your mention of meeting the dude who designed the glass structures at Apple. And again I mean that respectfully. Why do people mention these things? I went to a WHO concert, but I'd never tell anyone how to play a guitar. I saw Michael Jackson but still don't have a sense of rhythm.
There is no single structural engineer who designs Apple stores. If you met the guy who gets the credit, then you probably met James O'Callaghan. But I doubt he would say "he" designed the glass structures at Apple Stores. At least, I hope he didn't say it that way. For sure, if he heard you say that he told you, "structural glass is stronger than concrete." He'd ask you to stop because that would be a careless and incorrect generalization. I am no O'Callaghan but, for your sake, I suggest you stop repeating the same generalization, and respect the complexity of engineering. What engineers can do with glass is remarkable. But advances in concrete is no less so. In fact, you'd be amazed what happens when the two are mixed.
Finally, if you are so sure structural glass is stronger than concrete, please take a picture next time you are in a skyskraper where all the load bearing columns are made of glass alone. And if you really believe glass is stronger than steel, please take a video next time you see a construction crew drive glass piles into the ground to support a new building or bridge. Please wear safety glasses when you do this
Quote:
...Foster + Partners, the design firm Apple has tapped to revamp the look of its retail chain....
Not really the right metaphor, IMO, until Apple starts selling shoes--which may be on the horizon! Shoe-phone anyone?
...missed it by THAT much!
Sure and this is why I said "However, each material suffer weakness some how...". By the way, mechanics of materials and strength of materials are the same subject. It just that some call it strength and some call it mechanics.
If we were talking about music and WHO concert and your meeting has something to do about this discussion then sure, why not bring it up. We are here at public discussion forum where people share their knowledge and experiences.
It was Tim Macfarlane of Dewhurst Macfarlane and Partners. James O'Callaghan used to work for him before leaving to start his own business. He did not tell me HE designed Apple stores. He mentioned during his keynote that their office designed the NY Apple store among other projects. My conversation with him was about general engineering design issues.
Can you point to me where I said he told me "structural glass is stronger than concrete."? There is large number of research related to structural glass. It is even included in building codes. You can find all the information you need about properties of structural glass. I am not going to link to online resources (Wikipedia and others) here because as an engineer I don't use these resources professionally. But if you want you can.
I know all about concrete. My dissertation and funded research are related to concrete
You are implying that I said since glass is stronger than concrete then glass is the ultimate material. I never said that. In fact if you read my post again you will notice that I said that glass have its flaws.
Quote:
Originally Posted by NasserAE
You are implying that I said since glass is stronger than concrete then glass is the ultimate material. I never said that. In fact if you read my post again you will notice that I said that glass have its flaws.
But it should not be said that structural glass is stronger than concrete ... period.
Quote:
Originally Posted by NasserAE
I know all about concrete. My dissertation and funded research are related to concrete
And I was on your thesis committee and voted to fail you because you used Young's modulus as the sole parameter to compare strength, and erroneously thought mechanics of materials is only about strength of materials. But seriously, how the hell do such declarations bring meaning to a discussion? Are you going to bring up your grandmother's credentials too? Did she mislead you about mechanics and strength of materials being the same thing? That's like saying the sky and clouds are the same thing.
BTW, no one but no one knows all about concrete.
Your arguments, such as this one, read like they're straight out of the Wikipedia page on mechanics of materials.
Quote:
Originally Posted by ankleskater
Your arguments, such as this one, read like they're straight out of the Wikipedia page on mechanics of materials.
This just proof that you don't know about the subject and tried to use Wikipedia. But since my statement is right and you couldn't proof otherwise you accuse me of using Wikipedia as a source. Nice try.
I see that a lot of tech giants are constructing a wonderful physical presence. Floating roof, hmmm
Quote:
Originally Posted by stelligent
Well, he isn't right. Neither are you. Especially based on the mechanics of materials. In your instance, I am correcting you respectfully because you are generally respectful.
First of all, we cannot use a single parameter to compare their "strength". Some will, again, accuse me of spouting tripe. But if we are invoking mechanics of materials, we should do it correctly. Second, Young's modulus is a measure of stiffness. In a general context, it may seem intuitive to believe that stiffness is strength. But is it that simple in the context of the durability of a building? Furthermore, what is the Young's modulus for glass? What is it for concrete? That's like asking how tall are buildings? And which direction are you measuring Young's modulus in? Like the perceived brightness of the sun, direction matters.
And we haven't even gotten into yield strength, tensile strength, compressive strength, fatigue, impact ... There is a reason the field is called mechanics of materials and not simply strength of materials.
I am going to resist sneering at your mention of meeting the dude who designed the glass structures at Apple. And again I mean that respectfully. Why do people mention these things? I went to a WHO concert, but I'd never tell anyone how to play a guitar. I saw Michael Jackson but still don't have a sense of rhythm.
There is no single structural engineer who designs Apple stores. If you met the guy who gets the credit, then you probably met James O'Callaghan. But I doubt he would say "he" designed the glass structures at Apple Stores. At least, I hope he didn't say it that way. For sure, if he heard you say that he told you, "structural glass is stronger than concrete." He'd ask you to stop because that would be a careless and incorrect generalization. I am no O'Callaghan but, for your sake, I suggest you stop repeating the same generalization, and respect the complexity of engineering. What engineers can do with glass is remarkable. But advances in concrete is no less so. In fact, you'd be amazed what happens when the two are mixed.
Finally, if you are so sure structural glass is stronger than concrete, please take a picture next time you are in a skyskraper where all the load bearing columns are made of glass alone. And if you really believe glass is stronger than steel, please take a video next time you see a construction crew drive glass piles into the ground to support a new building or bridge. Please wear safety glasses when you do this
@stelligent: Couldn't agree more.
@NasserAE: ; Making the generalization that glass, or any other material, is "stronger" that concrete is ludicrous without qualifying under what circumstances it is "stronger". Reinforced concrete relies on a specific recipe developed for that use and then multiple types of tests to prove the performance of the actual product used on site. (Cylinders are compressed to test the compressive strength, beams are broken to test the flexural strength, a slump cone is done to measure its workability before placing, the reinforcing steel is tested and graded before it is ever delivered. My point is that one would need to specify the actual grade of concrete required (usually specified by numbers of sacks of cement per yard, slump, additives, special aggregate, etc… but ultimately by its compressive and flexural strength at given times after placing and curing under same conditions (typically 7 and 28 days and less a quick set batch is called for). Similars types of standards would apply to structural glass used in a building (although delivered ready to place). I cannot speak to the specifics of the standards for describing the structural properties of glass but do know they exist (and vary widely depending on the formula for the glass and how it is produced).
Quote:
Originally Posted by NasserAE
Sure and this is why I said "However, each material suffer weakness some how...". By the way, mechanics of materials and strength of materials are the same subject. It just that some call it strength and some call it mechanics.
If we were talking about music and WHO concert and your meeting has something to do about this discussion then sure, why not bring it up. We are here at public discussion forum where people share their knowledge and experiences.
It was Tim Macfarlane of Dewhurst Macfarlane and Partners. James O'Callaghan used to work for him before leaving to start his own business. He did not tell me HE designed Apple stores. He mentioned during his keynote that their office designed the NY Apple store among other projects. My conversation with him was about general engineering design issues.
Can you point to me where I said he told me "structural glass is stronger than concrete."? There is large number of research related to structural glass. It is even included in building codes. You can find all the information you need about properties of structural glass. I am not going to link to online resources (Wikipedia and others) here because as an engineer I don't use these resources professionally. But if you want you can.
I know all about concrete. My dissertation and funded research are related to concrete
You are implying that I said since glass is stronger than concrete then glass is the ultimate material. I never said that. In fact if you read my post again you will notice that I said that glass have its flaws.
I guess he didn't realize he was replying to an engineer who actually is required to know this information to be able to do their jobs.
I can't not comment on this. Your friend was building a house where the bedrock was close to the surface and he was afraid of liquifaction if an earthquake happened??
Uh, which is it? It can't be both. Liquifaction happens where there is filled land and weak soil types, *not* in areas close to bedrock.
And a comment about earthquake safety where there's a lot of glass: seismic codes are designed to minimize as much as possible loss if life and injury. A glass structure may seem dangerous, but the point is to design the structure so people aren't hurt or killed. This determines the kind of glass that's allowed. Think of a large store window or even a car windshield. The glass will break if damaged or broken, but won't cause injury. I'd rather be hit by pieces of falling safety glass than by a large beam, but no one worries about beams.