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Aiming at the high-speed railway (HSR)-China Railway Track System III (CRTS III) slab ballastless track (SBT)-simply-supported bridge system, the mapping relationship between girder deformation and rail deformation had been deduced theoretically, and then, the additional irregularity of the rail was obtained. A dynamic model of the high-speed train-track-bridge (TTB) coupling system was established according to existing theory on the high-speed TTB dynamic interactions. Combined with the mapping relationship, taking the superposition of the additional irregularity and the random irregularity as excitation, the dynamic response of two train models (CRH2 and ICE3 trains) was analysed by using the high-speed TTB coupling system model. The recommended thresholds of girder deformation were given based on running safety and ride comfort indicators. The results show that the sensitivities of the two train models exposed to girder deformation were different, and the CRH2 train was more sensitive to the lateral girder deformation. The non-uniform dislocation deformation of multiple girders exerted a slightly more significant effect on the dynamic characteristics of two train models than the dislocation deformation of single girder. Under the same amplitude of girder deformation, the influences of vertical girder dislocation and vertical girder rotation on the running safety and ride comfort of trains were significantly greater than that of lateral girder dislocation and lateral girder rotation. Acceleration and wheel-rail force increase rapidly in the area of girder deformation. To guarantee running safety and ride comfort of trains, this paper proposes suggested values for girder deformation thresholds. [ABSTRACT FROM AUTHOR]

The variation law of concrete surface resistivity is studied in this paper, by changing five different factors such as fine aggregate type, fly ash and slag powder content, water-cement ratio, ambient temperature and curing method, which lays the foundation for the application of surface resistivity in concrete engineering. The research results show that: under the same age and the same maintenance mode, the change of fine aggregate type has basically no effect on the surface resistivity of concrete; the change in the amount of fly ash and slag powder has some influence on the concrete surface resistivity, but the degree of influence is small; changes in water-cement ratio and ambient temperature have a greater effect on the concrete surface resistivity. The change law of resistivity varies with the age, whether it is in the wet curing mode or the dry curing mode, and the curing mode has a great influence on the concrete surface resistivity. [ABSTRACT FROM AUTHOR]