Question

Two concrete spans,of a 250m long bridge,are placed end to end so that there is no room allowed for expansion.If a temperature increase of 20.0°C occurs,what is the height y to which the spans rise when they buckle?

Answer 1

After the temperature rises by 20°C, the new length of a 125-m-long span is

$$L_f=L_i (1+αΔT)=125.03\text{ m}.$$

By the Pythagorean theorem:

$$\Delta h=\sqrt{L_f^2-L_i^2}=2.74\text{ m}.$$