Probabilistic assessment of deterioration and strength of concrete bridge beams and slabs
A probabilistic based assessment procedure for the prediction of the remaining service life of reinforced concrete bridge beams and slabs subject to reinforcement corrosion has been developed. By modelling the corrosion of reinforcement as a two stage process consisting of an initiation period and a...
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Imperial College London
2002
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| Online Access: | http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540519 |
| Summary: | A probabilistic based assessment procedure for the prediction of the remaining service life of reinforced concrete bridge beams and slabs subject to reinforcement corrosion has been developed. By modelling the corrosion of reinforcement as a two stage process consisting of an initiation period and a propagation period, analytical methods have been developed and used to estimate the probability of failure with time for a number of limit states. The most common form of deterioration has been identified as the corrosion of reinforcement due to the ingress of chloride ions from de-icing salts applied during the winter period. Fick's second law of diffusion has been used to model the transportation mechanism of chloride ions in concrete. Usually the effect of any spatial variation that may be exhibited by the model parameters is neglected. However in this instance the probability of the onset of corrosion with time has been evaluated using random field theory. This allows the spatial variability exhibited by some of the model parameters to be incorporated into the analysis. Subsequent to the onset of corrosion the loss of the steel cross-sectional area and eventual spalling of the concrete will adversely affect the structural performance of the bridge elements. An algebraic formulation based on simple material properties has been proposed to evaluate the load bearing capacity of reinforced concrete beams subject to general or localized corrosion. In each case the resulting probability of failure with time for a number of limit states has been evaluated. One of the most commonly used methods of assessing the load bearing capacity of slabs is yield line theory. In conventional yield line analysis the development of inplane membrane forces is neglected. However, laterally restrained bridge deck slabs have been known to support loads well in excess of the design loads. Hence an analytical model has been formulated to predict the enhanced ultimate load bearing capacity of laterally restrained concrete slabs. Using the proposed model the reliability of a deteriorating solid bridge deck slab spanning in one direction and clamped at both ends has been evaluated. Various degrees of reinforcement corrosion and available surround stiffness have been considered. |
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