993002025 林祐民 作業三

Hello, everyone. My name is Lin Yong Min. Today I’d like to give a speech. The topic is about engineering for earthquake. This bridge is a steel arch. Because it’s a test for earthquake. All that I can do is make it stronger. So I add some safety feature like bearing、ductile materials、shock absorbers.

Now let’s use the earthquake with magnitude of 8.5 on Richter scale to text this arch. Oh no! It’s destroyed. What happened to it? I think, maybe, the connection of steel and concrete mass the stress so that it is easy to be destroyed .

Then, this is cantilever truss. When I used the earthquake with the same magnitude to text this truss, it was also destroyed. Why? I think, maybe, the earthquake is so powerful that the cantilever off of its pier.

And then, these bridges called suspension and cable stay are stronger. When earthquake happened, the part of these bridges farther from the epicenter is damaged. Why? I suppose that the earthquake made these bridges wave. But the shock is so powerful that these bridges can’t bear the shock. Like tsunami, it is only wave in the beginning, but as time goes on, it forces the water into a giant wave. So it is so powerful that it can destroy everything.

This bridge is called beam girder. Only this type of bridge can bear the earthquake with magnitude of 8.5 on Richter scale. So I draw a conclusion that the beam girder is the strongest bridge of all types. Think you for listening.