Keiichi KIKUCHI
Problems in inspection and estimation for repair design and proposal of countermeasures based on LCC
Takumi SHIMOMURA
In Japan, a large number of bridges located near coastal areas are seriously deteriorated as a consequence of airborne salt attack. And maintenance is required in order to repair these structures. However, there are several problems to be solved in the inspection and repair design. Furthermore, in the near future, maintenance in many bridges will be necessary. So the development of a simplified maintenance planning method is required.The objective of this study is to solve the problems concerning the inspection and estimation of maintenance work and to propose a simplified maintenance planning method based on LCC comparison which considers the deterioration prediction.
First, after identifying common problems clarified in previous research works and interviews, proper countermeasures methods were proposed.
Then, a simplified maintenance method was proposed applying repair countermeasures to a virtual bridge. The effect of salt damage environments in maintenance methods was considered using different values of surface chloride ion concentrations, thus separating the results into different deterioration cases.
The accuracy of the method was confirmed by comparing the degradation estimation and repair cost based on the proposed method to information obtained from an actual bridge.
In cases with severe salt environments, a preventive maintenance management is recommended. On the other hand, for cases with mild salt environments, maintenance management after degradation helps to minimize the LCC of structures.
Finally, measurement of airborne salt in the coastal area of Niigata Prefecture was conducted. From these results, a maintenance management strategy for bridge in the coastal area of Niigata was proposed.As a result, it is possible to make rational maintenance plan in terms of LCC reduction according to each structure type (RC bridge or PC bridge) and the distance from the coast. Taking preventive maintenance measures under severe environments or giving maintenance to the bridge after the structure deteriorates in case of mild salt environment can help reducing LCC and increasing the bridge¡Çs service life
Please use "previous botton" to return the previous page