Question

The New River Gorge Bridge in West Virginia is a steel arch bridge 518 m in length. How much does the total length of the roadway decking change between temperature extremes of –20.0°C and 35.0°C? The result indicates the size of the expansion joints that must be built into the structure.

Answer 1

Answer:

$\Delta l=93.24\ mm$

Explanation:

Given:

length of steel arch bridge, $l=518\ m$

temperature difference, $\Delta T=35-20=15^{\circ}C$

We have,

coefficient of linear expansion of steel, $\alpha = 12\times 10^{-6}\ ^{\circ}C^{-1}$

So, the change in length of the bridge:

$\Delta l=l.\alpha.\Delta T$

$\Delta l=518\times 12\times 10^{-6}\times 15$

$\Delta l=93240\times 10^{-6}\ m$

$\Delta l=93.24\ mm$

Above value must be the size of expansion joints.