ABSTRACT
The design and construction of the piers for overwater bridges present a series of demanding criteria. In service, the pier must be able to support the dead and live loads successfully, while resisting environmental forces such as current, wind, wave, sea ice, and unbalanced soil loads, sometimes even including downslope rock fall. The design loadings for overwater piers are generally divided into two limit states, one being the limit state for those loadings of high probability of occurrence, for which the response should be essentially elastic. The second limit state is that of low-probability events, often termed the “safety” or “extreme” limit state. Construction of overwater bridge piers has an unfortunate history of delays, accidents, and even catastrophes. Open caissons are effective but costly, due to the large quantity of material required and the labor for working at the overwater site.
