Thermal conductivity and stress field analysis of reinforced concrete using an equivalent parameter approach

In major projects such as wind turbine bearing platforms, temperature-induced stress cracking of massive reinforced concrete foundations poses a core hazard to the safe service of structures, and traditional analysis methods struggle to accurately quantify the regulatory effect of reinforcing bars on temperature and stress fields. This paper proposes a method for calculating the effective thermal conductivity tensor of reinforced concrete considering the heat conduction effect of rebars from the perspective of isothermal flow rate. Additionally, a method is introduced to calculate the equivalent mechanical parameters considering reinforcement bars deformation. Based on these equivalent parameter calculation methods, combined with finite element simulation, an accurate assessment of the thermodynamic performance evolution of mass reinforced concrete is conducted. By comparing the finite element simulation results obtained from detailed modeling methods and those obtained from equivalent parameter methods, the effectiveness of this approach in predicting temperature and stress field changes in reinforced concrete is demonstrated. Real-time monitoring of temperature changes in 15 wind turbine bearing platform foundations reveals the temperature development pattern and cracking risk of foundation concrete. Furthermore, based on design drawings, this paper reconstructs the three-dimensional structure of reinforcement bars in foundation and couples it with the solid model of foundation concrete using the aforementioned equivalent method for a quantitative analysis of the impact of rebars on foundation concrete temperature and stress fields. Simulation results show that under the influence of rebars, the heat exchange rate of foundation increases, and the maximum temperature rise of local concrete can be reduced by over 8°C. Moreover, the maximum tensile stresses on the surface and inside of the concrete are reduced by 0 to 0.82 MPa and 0 to 1.89 MPa, respectively, thereby reducing the risk of cracking.