Abnormality estimation apparatus, abnormality estimation method, and computer-readable recording medium

An abnormality estimation method comprising:

• detecting a vibration response when a vehicle passes over an expansion and contraction apparatus, using vibration information indicating vibration that occurs in a bridge;
• calculating a first index for determining the presence or absence of an abnormality in the expansion and contraction apparatus, using the vibration response;
• and
• estimating the presence or absence of an abnormality in accordance with a change in the first index.

A non-transitory computer-readable recording medium that includes a program recorded thereon, the program including instructions that cause a computer to:

• detect a vibration response when a vehicle passes over an expansion and contraction apparatus, using vibration information indicating vibration that occurs in a bridge;
• calculate a first index for determining the presence or absence of an abnormality in the expansion and contraction apparatus, using the vibration response;
• and
• estimate the presence or absence of an abnormality in accordance with a change in the first index.