4 ms·

I don't want to doubt you, but this sounds like 'folk wisdom' or 'common sense' logic, rather than fact. You are not seriously claiming that every piece of land

I don't want to doubt you, but this sounds like 'folk wisdom' or 'common sense' logic, rather than fact. You are not seriously claiming that every piece of land is hit by earthquakes or hurricanes once every 50 years? While they get lots of attention my guess would be this is a shark attack-like phenomenon: its so unusual that its news worthy, which is why people think it is more frequent than it is. There are certainly earthquake (and hurricane) areas but the majority of the US population does not live in those. I'd need some risk/benefit analysis and actual data before believing they are even a factor in the equation for most people and areas. I can think of 100 other possible reasons (eg historically people moved frequently, or it was simply cheaper to rebuild than maintain as building standards/expectations change frequently, or in the cities you anyway expect someone to come in and buy up old building stock and rip it all down to put something bigger in, or ... ).

Enginerrrd 5y ago
OP is exaggerating a bit, but mostly spot on. There's a wealth of information this. See ASCE 7-16 Minimum Design Loads and Associated Criteria for Buildings and Other Structures, For wind: Chapters 26-31 for 144 pages of wind load design criteria. (California Building Code and International Building Codes recognize and point to that standard) Of particular note, is a concept called "Basic Wind Speed" which is derived from mapped values. What you'll find is that its intimately correlated with hurricane landing. Most people live on the coast in the US where the wind speed is highest. Depending on the risk category of the building, a typical value on the West coast is ~105 mph. On the east coast, it vaires by latitude from ~115-200 mph, increasing in all the areas that get hit by hurricanes. To address your skepticism, I assure you things like hurricanes are undeed a significant design concern. The seismic load is similar. Both loads are fundamentally designed to give a defined risk of failure from storms and earthquakes with particular recurrence intervals ranging from 50-100 years. (Offhand, I believe this value is ~1% for total collapse with a much higher risk of damage.). It is indeed carefully weighted and considered balance between risk reduction and feasibility, and indeed, having less than 1% risk for intervals over 100 years starts to get rather difficult. We still require it for schools, police stations, and emergency gathering locations and the like, but not normal houses.

Enginerrrd 5y ago

OP is exaggerating a bit, but mostly spot on. There's a wealth of information this. See ASCE 7-16 Minimum Design Loads and Associated Criteria for Buildings and Other Structures, For wind: Chapters 26-31 for 144 pages of wind load design criteria. (California Building Code and International Building Codes recognize and point to that standard) Of particular note, is a concept called "Basic Wind Speed" which is derived from mapped values. What you'll find is that its intimately correlated with hurricane landing. Most people live on the coast in the US where the wind speed is highest. Depending on the risk category of the building, a typical value on the West coast is ~105 mph. On the east coast, it vaires by latitude from ~115-200 mph, increasing in all the areas that get hit by hurricanes. To address your skepticism, I assure you things like hurricanes are undeed a significant design concern. The seismic load is similar. Both loads are fundamentally designed to give a defined risk of failure from storms and earthquakes with particular recurrence intervals ranging from 50-100 years. (Offhand, I believe this value is ~1% for total collapse with a much higher risk of damage.). It is indeed carefully weighted and considered balance between risk reduction and feasibility, and indeed, having less than 1% risk for intervals over 100 years starts to get rather difficult. We still require it for schools, police stations, and emergency gathering locations and the like, but not normal houses.