Fatigue and dynamic load measurements on modular expansion joints

Abstract

Modular expansion joints are commonly used on bridges with expansion and contraction movements in excess of 127 mm. These joints ensure a serviceable bridge surface, and protect the structure and substructure against water damage. However, these joints are dynamically loaded by truck wheels crossing the joint, and severe fatigue damage has been noted. The various types of modular joints are discussed, and fatigue damage on one joint is described. Analytical studies considering the static and dynamic behaviour of the joint are summarized, and the results are correlated to fatigue design methods. Preliminary results from an experimental study of field measurements of joint behaviour are provided. The results indicate that the load spectrum is a very important element in the fatigue life of these joints. Acceleration and braking of the truck traffic induces large horizontal forces on the joint, and is a primary contributor to the fatigue damage.