engleski

Maintenance and Reliability of the Krk Bridge

The paper describes deterioration, maintenance and rehabilitation planned and performed on the Krk Brigde. The bridge connects the island of Krk with the Croatian mainland with two large reinforced concrete arch spans of 390 and 244 m. The former is the 2nd and the latter is the 15th largest reinforced concrete arch span in the world. It was completed in 1980. The bridge is located in an extremely aggressive maritime environment with frequent high winds spraying sea-salt on the exposed surfaces. Combination of these harsh environmental conditions, exceptionally small concrete cover, minimal statically admissible cross-sectional dimensions of structural members, inadequate detailing of the superstructure supports and poor maintenance led to the bridge&#8217 ; s premature deterioration. Severe cracking, peeling and splitting off of concrete with exposed corroded reinforcement was identified and after 20 years of service the Krk Bridge is in a need of an immediate repair, particularly the structural members of its smaller span. Some repairs have already been performed, a lot of protective systems evaluated and rehabilitation design for superstructure supports has been developed and carried out on some supports. The structural performance was evaluated on a basis of detailed dynamic analyses and &#8220 ; in-situ&#8221 ; testing under controlled traffic loads and wind loads. These revealed that in some aspects the bridge behaviour does not conform to the design assumptions. Therefore, bridge rehabilitation planning and design should take into account the test-determined parameters of the bridge&#8217 ; s dynamic performance. The premature deterioration of this bridge of remarkable size and significance is a lesson to be taken seriously, both in the design of new bridges and maintenance planning of existing ones in order to avoid repair and rehabilitation works of exceptionally high cost and doubtful result.

Reinforced Concrete Arch Bridge; Bridge Maintenance; Rehabilitation; Supports; Dynamic Analysis; Bridge Reliability

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