Thermo-mechanic Damage Analysis And Optimization Design Of Snow-melting Heated Pavement And Bridge Deck

Compared with other snow-melting methods,the electric snow-melting method has many advantages,such as high efficiency of snow-melting,and convenient and so on.In recent years,many scholars in Europe,American and Japan,have done a lot of research on the numerical simulation and heat transfer model of the electric snowmelting method.Meanwhile,the electric snow-melting method have been applied in practical projects.However,there are a little research on temperature damage which caused by the electric snow-melting method.This study combined with the practical project,according to the different structure of snow-melting heated pavement and bridge deck,the finite element models are established respectively.Based on the snow-melting performance and temperature damage,the structures are optimized.The work which has been carried out is as follows:(1)The working mechanism of snow-melting heated pavement and bridge deck was analyzed.Its working process is divided into two stages: heat transfer analysis and damage calculation.What’s more,the basic theory of heat transfer and the derivation process of concrete constitutive relation were analyzed.Based on that,a method of establishing the thermo-mechanic damage finite element model was obtained.(2)The thermo-mechanic damage finite element model of snow-melting heated pavement was established.It is concluded that the temperature load is the main factor of pavement damage.The effects of pavement structure and external conditions on pavement damage were analyzed.The relationship between pavement damage and the 5 factors had been proposed.Meanwhile,based on the elevated temperature,the simplified pavement damage relationship and the cumulative damage prediction model are obtained.(3)The small full scale slab of snow-melting pavement was formed,and the thermodynamic properties of the small full scale slab were analyzed.The surface temperature distribution is wavy.The strain was related to distance with heat pipes and unrelated to the depth of the heat pipe.(4)The thermo-mechanic damage finite element model of snow-melting heated bridge deck was established.The influence of the thickness of the thermally conductive layer and the spacing of the cable on the snow-melting heated bridge surface was analyzed.A structure optimization method based on surface temperature and damage was proposed.The optimum thickness of the thermally conductive layer is 0.5cm,and the optimum spacing of the cable is 6cm.(5)The construction technology and relevant measures are carried out based on the Fuxin Highway Bridge Engineering in Anhui province.The surface temperature increases with the increasing of heating time,and the heating process mainly includes three stages.The strain increases with the increasing of heating time,and the strain in the center is maximum.