Editor's comment

摘要

Long-span bridges have always held a fascination for structural engineers - and indeed, for the general public - with the longest bridges of each type generally categorised by their worldwide rating. When a new record is set, as seems to happen on a regular basis, the latest title-holder is accorded great publicity and guaranteed an audience around the world. But as our supplement makes clear, the biggest challenges in long-span bridge engineering are not necessarily the record-breaking structures. These may be challenging when they are under construction - particularly if they are being built in regions which experience extreme weather conditions - but often they employ tried and tested design approaches and construction technologies, with the longer spans generally driven by topography or other project-specific criteria.