4 ms·

Theres a whole field of structural reliability, and it's where they come up with load and resistance factors for design equations, and material testing requirem

by ggcdn 8y ago

Theres a whole field of structural reliability, and it's where they come up with load and resistance factors for design equations, and material testing requirements. I believe the targets are such that the probability of collapse of any structural component over it's lifetime is less than 10%, if it was designed for a utilization of 1.0. In reality, sizes are bumped up so the probability should be even less. In countries with strong regulatory requirements, you generally don't have to worry about builders 'diluting' because it is inspected by the design engineer and tested by 3rd party testing companies. It is in the engineers best interest to ensure compliance because they are legally liable in that regard. You can actually be suspended from practicing engineering if you do not comply with field review requirements. If our design calls for 35MPa concrete, samples are taken at the job site, tested, and reported back to the contractor and designer. If they come up short, it gets remediated.

donavanm 8y ago
The issue is that components dont build systems. Sure, maybe that get concrete that tests to 35Mpa. But was the embedded steel reinforcement coated properly, or will it rust? Were the balconies and doors sealed? Did anyone wash grout down the drains? And then imagine someone finds a problem, like “leaks” in a sibling comment. Do they revisit the strucutral issues that led to it? Or do they patch it up with a new 3rd party tradie and walk away? The idea being that your point inspection are finite. And the responsibility will be laundered behind a legal or organizational structure. Youre not going to reach anyone “responsible” for systemic issues. And as soon as you do that youll dampen all relevant investment activity. See the Washington State Condominium Act for a great example.
stevekemp 8y ago
And yet the UK continues to have mini-scandals : https://www.bbc.com/news/business-46454844 https://www.bbc.com/news/business-46454844
- ggcdn 8y ago
  Not sure about UK, but where I'm from this type of single family home construction discussed in the article doesn't normally require a structural engineer. In that case, you really are depending on the reputation of the builder.

by ggcdn 8y ago

donavanm 8y ago

The issue is that components dont build systems. Sure, maybe that get concrete that tests to 35Mpa. But was the embedded steel reinforcement coated properly, or will it rust? Were the balconies and doors sealed? Did anyone wash grout down the drains? And then imagine someone finds a problem, like “leaks” in a sibling comment. Do they revisit the strucutral issues that led to it? Or do they patch it up with a new 3rd party tradie and walk away? The idea being that your point inspection are finite. And the responsibility will be laundered behind a legal or organizational structure. Youre not going to reach anyone “responsible” for systemic issues. And as soon as you do that youll dampen all relevant investment activity. See the Washington State Condominium Act for a great example.

stevekemp 8y ago

And yet the UK continues to have mini-scandals : https://www.bbc.com/news/business-46454844 https://www.bbc.com/news/business-46454844

ggcdn 8y ago
Not sure about UK, but where I'm from this type of single family home construction discussed in the article doesn't normally require a structural engineer. In that case, you really are depending on the reputation of the builder.