Integration Research Of Material And Structure Of Double-Layer SMA Steel Bridge Deck Pavement

SMA steel bridge deck pavement often adopts double layer structure to provide sufficient strength and deformation coordination.However,cracks,rutting and other diseases still occur in the SMA steel bridge deck pavement due to the complex internal stress action of the pavement layer and limitations of material properties.In this paper,the finite element simulation of double-layer SMA steel bridge pavement is carried out to analyze the influence of material parameter variation on structural mechanical response.In order to guide the material composition design of pavement layer,and recommend the combination type of double-layer SMA steel bridge deck pavement structure.The finite element model of double-layer SMA orthotropic steel bridge deck pavement structure was established by ABAQUS,and the dynamic modulus change of pavement layer is analyzed to the mechanical response of pavement structure The influence of nominal maximum particle size,binder type,gradation and other factors on the dynamic modulus of SMA was studied,and the mixture composition was designed based on the mechanical response law of pavement structure.The applicability of the mixture on the upper and lower of pavement was evaluated by weighted ranking,and then the high-temperature stability and low-temperature crack resistance of the composite type of steel bridge deck pavement was studied.Combined with the results of the performance research of the pavement combination of steel bridge,steel bridge deck pavement combination type is recommended.The main research conclusions are as follows:(1)The most unfavorable load was determined to be above the joint between the U-rib and the steel deck at the center of the two adjacent diaphragms.With the decrease of the dynamic modulus of the upper layer of pavement and the increase of the dynamic modulus of the lower layer of pavement,the tensile stress and shear stress of the pavement structure decrease,and the possibility of pavement structure disease is reduced.(2)The dynamic modulus of the mixture increases with the increase of the nominal maximum size;In the same nominal maximum particle size,the gradation of the mixture is finer,and the dynamic modulus increases;The dynamic modulus of SBS modified asphalt mixture is lower;The dynamic modulus of the mixture decreases with the increase of temperature and increases with the increase of loading frequency.According to the mechanical response law of pavement structure,SMA13(course)and SMA-10(fine)were selected as the optimal SMA mixture for steel bridge deck pavement.(3)The pavement performance of asphalt mixture suitable for the upper layer of pavement was ranked as SMA-13(SBS)>SMA-10(SBS)>SMA-13(RST)> SMA-10(RST).The pavement performance of asphalt mixture suitable for the bottom layer of pavement was ranked as SMA-10(SBS)>SMA-13(SBS)>SMA-10(RST)>SMA-13(RST).(4)The steel bridge deck pavement structure combination type of upper layer SMA-13(SBS)+ lower layer SMA-10(SBS)is recommended.