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Polyurethane concrete (PUC), as a new type of steel bridge deck paving material, the bond-slip pattern at the interface with the steel plate is not yet clear. In this study, the mechanical properties of the PUC and steel plate interface under the coupled action of temperature, normal force and tangential force were explored through shear tests and numerical simulations. An analytical model for bond-slip at the PUC/steel plate interface and a predictive model for the shear strength of the PUC/steel plate interface were developed.

The new shear test device designed in this paper overcomes the defect that the traditional oblique shear test cannot test the interface shear performance under the condition of fixed normal force. The universal testing machine (UTM) test machine was used to adjust the test temperature conditions. Combined with the results of the bond-slip test, the finite element simulation of the interface is completed by using the COHENSIVE unit to analyze the local stress distribution characteristics of the interface. The use of variance-based uncertainty analysis guaranteed the validity of the simulation.

The shear strength (τ_f) at the PUC-plate interface was negatively correlated with temperature while it was positively correlated with normal stress. The effect of temperature on the shear properties was more significant than that of normal stress. The slip corresponding to the maximum shear (D₁) positively correlates with both temperature and normal stress. The interfacial shear ductility improves with increasing temperature.

Based on the PUC bond-slip measured curves, the relationship between bond stress and slip at different stages was analyzed, and the bond-slip analytical model at different stages was established; the model was defined by key parameters such as elastic ultimate shear stress τ₀, peak stress τ_f and interface fracture energy G_f.

The fatigue problems of the carriageway slabs of reinforced concrete rib-beam bridges were studied. The analysis of the carriageway slabs could not achieve the actual stress state.

Based on this characteristic, the reinforced concrete T-beam group structure system was taken as the research object. Four scale models of the carriageway slabs of reinforced concrete ribbed bridges were designed. The fatigue failure modes and actual fatigue resistance of the carriageway slabs with different length-to-side ratios were systematically studied through static load and fatigue experiments. Based on this, the concrete damage plasticity model (CDP model) was combined with numerical simulation analysis to study the influence of the length-to-short-side ratio of the carriageway slab on the fatigue performance and the remaining bearing capacity.

The results show that the fatigue failure of the carriageway slab is a three-stage failure; the ratio of the long and short sides has a significant effect on the fatigue performance of the carriageway slab. Under the same fatigue load level, the smaller the ratio of the long and short sides of the carriageway slab.

The fatigue resistance of the unidirectional board is significantly lower than that of the bidirectional board. It is recommended to use the bidirectional board in actual engineering design.

The effects of fatigue load level and plate thickness on the fatigue performance of reinforced concrete T-beam bridges.

Fatigue load tests were performed based on the fatigue damage theory of reinforced concrete, combined with finite element model analysis. The other conditions are controlled separately, and the fatigue performance of the T-beam bridge carriageway slab under different fatigue load levels and different plate thicknesses is studied.

The fatigue process of the carriageway slab of a reinforced concrete T-beam bridge is divided into three stages: fatigue damage generation, fatigue damage development and fatigue failure. Under certain other conditions, as the fatigue load level increases, the fatigue damage of the carriageway slab accelerates; as the thickness of the carriageway slab increases, the fatigue resistance of the carriageway slab improves.

Tests and simulations have been carried out, but have not been applied to actual engineering for the time being.

Increasing the thickness of the carriageway slab in actual engineering is conducive to improving the fatigue performance of the bridge, and heavy-duty traffic has a greater impact on the durability of the bridge.

It has certain reference value for bridge design, inspection and subsequent maintenance and reinforcement.

The originality of this article lies in designing and carrying out static and cyclic load tests separately, while introducing material damage models based on a large number of references and combining finite element analysis to consider the impact of a specific factor on fatigue performance. The test and analysis results can provide reference for bridge design and inspection.