ABSTRACT
Working engineers, led by code writers and researchers, are inclined to separate arch bridges into digestible elements and ignore those which they cannot understand. Much careful research will be needed to overcome this problem, but a first stage is to identify and delineate the boundaries where behaviour may need further study. The authors have spent many hours discussing implications of certain aspects of arch construction. Recent journeys have exposed them to new bridges and new ideas. The view of system behaviour expressed reflects observation of structures where established views on behaviour are obviously not tenable.
