Question

The New River Gorge Bridge is 3030 feet long. The bridge is designed to withstand a temperature range of -40 ̊F to 140 ̊F. How much is the bridge going to expand and contract if the bridge is made of cement?

Answer 1

Change in length due to temperature change is given by:

dL = L0*alpha*dT

L0 = original length of bridge = 3030 feet = 923.54 meter

alpha = linear expansion coefficient = 13.5*10^-6

(Check this value in your reference book, as it can vary according to different sources and let me know if it's different)

dT = Tf - Ti

Tf = 140 F = 60 C

Ti = -40 F = -40 C

dT = 60 - (-40) = 100 C

Now

dL = 923.54*13.5*10^-6*100

dL = 1.2467 m

dL = expansion in length of bridge = 1.25 m = 4.1 ft

Please Upvote.

Again check the value of alpha in your reference book and let me know if it's different.