Inspection survey of 150 expansion joints in road bridges

摘要

Expansion joints are current equipment applied to almost every type of bridge with relatively high maintenance costs. Furthermore, their service life is generally short (often below 10 years) and lower than the bridge expected service life (over 50 years). In this paper, the results of an inspection campaign of 150 expansion joints in road bridges, the first comprehensive survey of the kind, are presented. They allow knowing and characterizing more properly the expansion joints installed in Portuguese roads and highways, namely in terms of their typology, pathology and rehabilitation. It was concluded that: (a) some types of joints have been systematically replaced (open joints, nosing joints with poured sealant, buried joints under continuous surfacing, steel sliding plates); (b) made-to-order joints are no longer prescribed; (c) the transition strip and the anchorage cavities need more maintenance and more frequent rehabilitation than other parts; (d) installment errors and lack of maintenance are the most frequent causes of pathology; (e) direct or indirect visual observation is still the best diagnosis method; and (f) the importance of the defects found depends a lot on the type of joint and of the defect.