| Due to the rapidly increasing traffic and vehicle loading in recent years, the live load level of highway concrete bridge has been increased obviously. Currently, the cover thickness of exsiting bridge deck slabs, which was built in the past, was relatively small and the corrosion of internal reinforcement was evident due to the application of de-icing salts. Therefore, the structural performance of the existing reinforced bridge deck slabs was deteriorated seriously. Until now, the major research works of strengthening method for the concrete deck slabs was focused on the flexural strengthening. However, numbers of research in the literatures reveals that the dominant failure mode of concrete deck slab without shear reinforcement can be shear failure other than bending failure. Consequently, it is necessary to develop a study of the effective strengthening method for the support location in concrete deck slabs.In recent years, more and more attention has been paid in the research field of strengthening method by using fibre-reinforced polymer(FRP) materials, such as method of externally bonded(EB) strengthening scheme and near surface mounted(NSM) strengthening scheme. However, those strengthening method is unavailable for shear strengthening in concrete deck slabs. Therefore, a promising strengthening method named as embedded through-section(ETS) is adopted as shear strengthening method for concrete deck slabs in this study. In addition, FRP bars are uses as strengthening materials. Currently, the study related to the ETS strengthening method,particularly for concrete deck slabs, is rather limited.As discussed above, A series of experimental tests of concrete deck slab carried out to study the shear behaviour of concrete slab strips in this thesis. Several structural parameters were varied to investigate the influence on the structural behaviour. Those variables includes ETS strengthening material, spacing of ETS bars, diameter of ETS FRP bars and the existing of drilling holes. In this study, the data of structural deformation, strain, loading-carrying capacity and failure mode is measured, observed and analysed. The influence of the different structural parameters on the structural behaviour is evaluated by the comparison of different test specimens.A commercial finite element software named as ABAQUS was used in the numerical analysis of the experimental model. The accuracy of the proposed finiteelemental model is validated by the comparison between numerical and experimental results. Thereafter, a series of parametric study was conducted and the results were presented and discussed.A theoretical prediction model for the shear capacity contribution of ETS strengthening bars was used in this study, which considered the bond-slip behaviour of ETS FRP and concrete. A modified BPE model bond-slip was used in this theoretical model. In the comparison of the results from the experimental and theoretical study, this predicted capacity of the proposed model showed good agreement with the test results.Additionally, the failure model can also be predicted by this method. This theoretical model can be used as an effective tool in the future study. |
