What is the safety factor when building bridges. If it's rated at eg. 1000 lbs, what would it be tested to. 1.5 times - 2 times etc?
- Adam DLv 72 months ago
In short, it's complicated.
Modern bridge design (in the United States) utilizes the Load Factor Resistance Factor (LRFD) method. In LRFD, each type of load (self weight, vehicular live load, wind load, etc.) has a specific factor applied which has been statistically calibrated based on years of data. Different combinations of loads, called load cases, have been developed (also using statistics), and a particular load could have different load factors in different cases.
The resistance of each component to a particular stress (it's strength) also gets a statistically calibrated factor. The same component may have a number of different resistance factors, one for each stress it must handle (bending, shear, tension, etc.)