Study On Durability Index System For Structural Elements Of Concrete Bridges

Recent years, based on practice of bridge engineering and research on structuraldurability of concrete bridge, The lacking of durability assessment technology based oncomponent is the direct reason for concrete bridge durability becomes more serious.After the index system for durability evaluation being studied through the existingconcrete bridge components, the durability evaluation method has been put forwardbased on the components. The method not only can reveal the potential danger andmake decision timely to maintain or dismantle to prevent major accidents, but also canbe directly used to guide structure design to obtain great economic and social benefits.Rely on the project, this paper has done the research as follows:(1) Based on the research results domestic and abroad, this paper studied structureof reinforced concrete bridge’s deterioration mechanism and its model, it alsosummarized the relationship between the factors which influence the durability.(2) Through the analysis and research on durability parameters and experimentresult of concrete component in and abroad, durability evaluation index for in-serviceconcrete bridge is given. Durability evaluation index limit is proposed with fullconsideration of stress characteristics, structural factor and partial environmental factor.This paper also establish the durability index system in different environment.(3) Based on several possibilities of touch the limit value, this paper put forwardsingle index evaluation and multiple indexes evaluation to evaluate the durability ofconcrete. Proposed using relative value of bearing capacity to be the evaluating index,analyzed the relationship between steel corrosion, concrete crack, spalling and bearingcapacity. Derived after corrosion bending capacity formula of typical section anddiscussed the quantitative relationship between corrosion rate and reduction of capacityunder two calculation models.Through the analysis of law of calculation, this paperproposed the range of capacity decrease in multiple indexes evaluation.At last, appliedsingle index evaluation to evaluate a bridge, the evaluating results match well with thetest,it proved the method is feasible.