End columns anchored to foundations are exactly plumb only when the steel is at ______ temperature.

End columns anchored to foundations are exactly plumb only when the steel is at ______ temperature.

• A. Cold
• B. Room
• C. Hot
• D. Normal

Answer: (D)

The key idea is that steel changes length with temperature. A column’s vertical alignment will differ depending on whether it’s hot, cold, or at normal operating temperature. If you tighten and plumb the end column while the steel is hot, it will shrink as it cools to normal temperature and can move out of plumb. If you plumb it cold, heating later will lengthen the member and can cause misalignment. Therefore, end columns anchored to foundations are set to be exactly plumb at normal (operating) temperature so that their alignment stays true when the structure reaches its typical temperature in service.

The key idea is that steel changes length with temperature. A column’s vertical alignment will differ depending on whether it’s hot, cold, or at normal operating temperature. If you tighten and plumb the end column while the steel is hot, it will shrink as it cools to normal temperature and can move out of plumb. If you plumb it cold, heating later will lengthen the member and can cause misalignment. Therefore, end columns anchored to foundations are set to be exactly plumb at normal (operating) temperature so that their alignment stays true when the structure reaches its typical temperature in service.