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CRTS III (China Railway Track System III) slab ballastless track structure is one of the high-speed railway ballastless track structures which has Chinese independent intellectual property rights. The mechanical performance of CRTS III slab ballastless track structure under temperature load has not been clear yet. Therefore, through temperature field model and temperature load values selected by statistics analysis based on long-term meteorological data, the mechanical performance of ballastless track structure is studied under two typical working conditions with different safety probability. It is found that the daily extreme values of monthly axial uniform temperature and the daily maximum temperature gradient obey certain statistical laws. In addition, the maximum tensile stress of the self-compacting concrete layer is located in the middle and edge of the slab bottom and the side of the slab. The maximum tensile stress of the base plate is located at the edge of the surface of the layer and the inner edge of the limiting groove. The interface normal tensile stress is located at the end and corner of the interface. Furthermore, maximum stress increases with the increase of safety probability.

This paper develops a novel dry connection utilizing high-strength bolts and introduces the corresponding low-rise precast wall panel structure system. To investigate the seismic performance of the structure system with full bolt connections, monotonic loading tests of the connection joint and cyclic lateral loading tests of three full-scaled precast shear walls are both conducted. Based on the test data, axial and shear mechanical models of the connection are given. Meanwhile, experimental results show that the failure mode of the connection is dominated by anchored rebar ductile rupture, and the precast structure system presents a stable energy dissipation capacity and a good seismic ductility. The numerical model of the precast shear wall is then developed and validated by the cyclic loading test. Also a simplified calculation method to predict the lateral strength of the precast shear wall is proposed. According to the calculation results, the distance between the center of the connection and the edge of the shear wall is suggested to be 150 mm, while the wall thickness is recommended to be 120 mm or 150 mm. Finally, a three-story precast wall panel structure is employed to assess the collapse performance of the proposed precast structure system by using the presented numerical model. The results indicate that the proposed structure system with full bolt connections has high stiffness and high seismic resistance against collapse.

Experimental investigations on self-compacting concrete (SCC) under uniaxial monotonic and cyclic compression taking into account the stochastic constitutive relationship were reported and conducted. By introducing a practical method on plasticity characterization into the fiber bundle-plastic chain model, a new constitutive model based on the statistic damage approach for describing the stochastic mechanical responses of SCC under uniaxial compression was proposed. The comparison between the experimental results and the predictions demonstrated that the proposed model was able to characterize the salient features for SCC under both uniaxial monotonic and cyclic compression. Furthermore, the stochastic evolution (SE) of SCC under uniaxial compression and a comparison between the SCC and normally vibrated concrete (NVC) in certain aspects were analyzed and discussed; it was concluded that the stochastic constitutive relationship of SCC under compression can be understood by a media process of transition from microscale to macroscale.