Some problems with arch bridge assessment and potential solutions

摘要

Arches with low dead load, and therefore low prestress may be susceptible to traffic damage under loads currently applied. Using current assessment rules these bridges appear to be safe. Using a distribution model which is more in line with anticipated behaviour is capable of yielding results which allow an engineer to differentiate effectively between bridges which are safe and those which may be in danger. A true representation of behaviour is not yet possible and may never be. It is a matter of some urgency that the potential for over estimation of capacity is acknowledged and research put in hand to investigate the causes thoroughly and test the models proposed here. In the meantime, it is unsafe, and therefore inadmissible to suggest that the current model should be used until a better one is proved. It would be better to give no guidance at all, and allow individual engineers to make their own judgments than to continue to offer guidance which is known to be, at best, flawed.