WEBVTT

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My name is Austin Nelson . I'm a

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structural engineer , subject matter

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expert with the Inland Navigation

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Design Center . Uh We're replacing the

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existing gates at the Black Rock Lock

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because they reached their fatigue life .

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Uh Essentially as you bend a paper clip ,

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think of the paper clip eventually

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breaking after you bend it so many

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times . And that's why we're placing

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the gates .

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The existing motor gates are

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horizontally framed , meaning the

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primary load carrying members are

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horizontal girders , transferring the

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load lock walls . The new gates are

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vertically framed , meaning the primary

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load carrying members are vertical and

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transfer the load into the sill and

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then into a large top grader that then

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transfers the load into the wall .

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The new motor gates are designed for

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100 year fatigue life . So ideally ,

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they will not get replaced for the next

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100 years .