Influence of incompatibility of thermomechanical parameters of bearing layers of a bridge structure on its thermo-stressed state

Viktor Gaidaichuk,Olena Bilobrytska,Liudmyla Shevchuk

doi:10.32347/2410-2547.2021.107.301-311

Viktor Gaidaichuk, Olena Bilobrytska + Show 1 more

Open Access

https://doi.org/10.32347/2410-2547.2021.107.301-311

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Abstract

On the basis of the theory of thermoelasticity, the problem of the thermally stressed state of a two-layer fragment of a bridge structure, consisting of a metal base and an asphalt-concrete upper layer, under conditions of a change in the ambient temperature at different values of the coefficients of thermal linear expansion of the layers is considered. Using the finite element method, the fields of thermal stresses, deformations and displacements are constructed for various values of the thermomechanical characteristics of the layers. The analysis of the influence of the values of thermomechanical parameters on the stress-strain state of the system is carried out. It is shown that with an increase in the incompatibility of these characteristics, the intensities of stresses and strains increase. The zones of concentration of these functions are found. It is recommended to use materials with close values of their thermomechanical parameters when designing bridges to avoid their premature destruction.

Highlights

In thermomechanics of substantially heterogeneous structures consisting of composite materials and layered massifs, the heterogeneity of thermal stress fields, their concentration and system strength largely depend on the inhomogeneity and incompatibility of their thermomechanical parameters
In [1] it is shown that an attempt to strengthen the asphalt concrete layer of the road surface with metal and nonmetallic reinforcing rods with different thermomechanical parameters can lead to unexpected negative effects associated with an increase in thermal stresses in the conjugation zones of contacting bodies
A special case in the thermomechanics of layered media arises if the medium has a low coefficient of thermal conductivity, and the ambient temperature changes rapidly over time

Summary

Introduction

In thermomechanics of substantially heterogeneous structures consisting of composite materials and layered massifs (for example, in road construction), the heterogeneity of thermal stress fields, their concentration and system strength largely depend on the inhomogeneity and incompatibility of their thermomechanical parameters (thermal conductivity coefficients, thermal linear expansion coefficients, moduli of elasticity, Poisson's ratios, etc.). It can be argued that the intensity of the indicated interlayer tangential stresses is primarily determined by the difference in the values of the coefficients of thermal linear expansion and the thickness of the asphalt concrete layer, which affect the incompatibility of deformations and displacements of contacting structural fragments that are subjected to alignment. In this case, the thickness of the metal layer of the bridge structure obviously plays a lesser role due to the low elastic deformability of steel. Calculations have confirmed the opinion that with an increase in the coefficient Т of asphalt concrete, the maximum values of shear stresses (c)

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Conclusions