About bridges. Just curious???

Question

I wonder how do they know the load limit on bridges?
Can you help me with this.

Thanks a lot.

Answer 1

engineers know the properties of the materials used. They also know the construction techniques used. They may calculate load limits bases on theoretical assumptions or they may construct a model bridge, put a load on it and increase the load until the bridge breaks. Knowing the characterists of the model, they can predict the characteristics of the real bridge.

Sometimes things can go wrong
--> http://www.enm.bris.ac.uk/anm/tacoma/tacnarr.mpg

Answer 2

First, the bridge undergoes a detailed inspection where all the geometric and material properties are determined and recorded. Then, a structural analysis is performed (computer model) and the bridge is assigned a load rating. The code which governs the loading criteria is put out by AASHTO.

Answer 3

There is "code" governing the construction and rating of bridges. Any time there is public safety involved, there is generally a requirement to comply to code and have that compliance inspected and certified.

Code was developed from trial and error, analysis of failures and through theoretical calculations. Even as complex an assembly as a bridge is, it is possible to calculate the amount of load it is able to take.

Answer 4

um idk my geometry teacher told us it had to do with the arch and materials used..... does that help? hope so...