April $13,2023$

CE $411$ Structural Dynamics and Earthquake Eng. Midterm

Q$1(10$ Points$)$: Engineers drew the graph shown below to understand the possible reasons of unexpected severe damage seen after an earthquake. Briefly discuss what might have caused such a damage pattern.

In the figure $x$ axis shows number of stories and $y$ axis represents the number of collapsed buildings

Stories

Q$2(5$ Points$)$: Which one is better in terms of mathematical accuracy, mode superposition or time history analysis why?

Q$3(5$ Points$)$: Which one is better in terms of statistical accuracy, mode superposition or time history analysis why?

Q$4(10$ Points$)$: Which one is easier to use acceleration spectrum or displacement spectrum, why? How do we convert displacement spectrum to acceleration?

Q$5(10$ Points$)$ What is liquefaction? How can we avoid destructive effects of liquefaction?