Evaluation of the structural integrity of timber bridges

Timber bridges are used on all types of rail lines including important main transcontinental rail lines. A combined structural dynamic and ultrasonic inspection approach is proposed for testing these bridges. This paper presents results of preliminary field tests. Dynamic excitation of the system is used to identify suspect elements in the bridge. Ultrasonic inspection is used to evaluate the suspect elements identified from global testing. The potential for on-site evaluation based on two different dynamic excitations is investigated. Testing of a bridge member using dry coupled ultrasonics is shown to demonstrate this technique on aged timber.