Viscoelasticity is an important characteristic of gussasphalt mixtures. The aim of this study is to find the correct viscoelastic material parameters of the novel gussasphalt applied in the 4th Yangtze River Bridge based on the modified Burgers model. This study firstly derives the explicit Prony series form of the shear relaxation modulus of viscoelastic material from Laplace transformation, to fulfill the parameter inputting requirements of commonly used finite element software suites. Secondly, a kind of uniaxial penetration creep experiment on the gussasphalt mixtures is conducted. By fitting the creep compliance, the viscoelastic parameters characterized by the modified Burgers model are obtained. And thirdly, based on the viscoelastic test data of asphalt mixtures, the Prony series formula derived in this study is verified through the finite element simulation. The comparison results of the relative errors between the finite element simulation and the theoretical calculation confirm the reliability of the Prony series formulas deduced in this research. And finally, a stress-correcting method is proposed, which can significantly improve the accuracy of model parameters identification and reduce the relative error between the finite element simulation and the experimental data.

<p>The influence of vehicle load on the force state of the paving layers for orthotropic steel decks in different seasons was studied in the research. To begin with, by applying the fourth Nanjing Yangtze River Bridge as the research object, this research established the model for the half cross-section of steel box beam (MHCSBB) using the ANSYS finite element software. Then, the finite element method was used to calculate the position which is most adverse for the force of the pavement layers under loading at different positions. Meanwhile, the influences of varying temperatures in different seasons and different overload proportions (30%, 50%, 70% and 100%) on the force state of the pavement layers were taken into account. Based on this, this research comprehensively analyzed the characteristics of the varying forces of the orthotropic steel deck under different vehicle loads. Finally, it was obtained that vehicle overloading should be effectively controlled under the conditions of low and high temperatures, so as to improve the force state and thus lengthen the service life of the pavement layer of the steel deck.</p>

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<p>This paper investigated the flexural performance of the UHPC deck based on Fifth Nanjing Yangtze River Bridge which is the first long-span cable-stayed bridge in China utilizing reinforced UHPC with basalt. Two types of the specimens were used to reveal the longitudinal and transversal flexural performance of the UHPC deck, respectively. The load (stress)-deflection curves and load (stress)- crack width curves of the specimens were obtained from the experimental and theoretical studies. The results showed that the UHPC deck in the elastic stage exhibited adequate bending stiffness and cracking strength. In addition, the formulas in the recommendation of AFGC were used to calculate the maximum cracks width of the UHPC deck. It showed that the formulas were not applicable to UHPC structures with coarse aggregates. Thus, there is a necessity to revise the formulas for UHPC structures with coarse aggregates.</p>