Search

Fiber-reinforced polymer–reinforced ballastless track slabs not only improve the insulation performance but also have advantages in their mechanical properties. The objective of the article is to propose a corresponding design method of the ballastless track slabs considering different parameters by a finite element analysis model. The deformation performance of the ballastless track slabs, as well as the prediction results of several models, was studied considering the different prestress levels, reinforcement ratios, and prestressed materials. The results show that ACI 440.4R-04 and Bischoff models are suggested for predicting the deflection of a ballastless track slab when the prestress level is between 30% and 60% and the Brown and Bartholomew model is suitable for those with a prestress level below 30%.

This paper presents experimental and theoretical investigations on the flexural utilised of FRP (fibre-reinforced polymer) rebar-reinforced ECC (engineered cementitious composite) beams subjected to freeze–thaw cycles. Eight FRP-reinforced specimens after subjected to 0, 50, 100 and 150 cycles of freeze–thaw were tested to failure under flexural loading. Experimental results show that the moment capacity decreases with the increase of freeze–thaw cycles regardless of the material used, but the decreasing rate of the reinforced ECC specimen is lower than that of the conventional reinforced concrete specimen. The bearing capacity, deflection and crack width of the reinforced ECC specimens under quasi-permanent combination of moments are 1.13 ~ 1.21, 0.66 ~ 0.90 and 0.71 times of those of the conventional reinforced concrete specimens, respectively. Due to the excellent tensile and durability performance of ECC materials, bearing capacity, stiffness and crack resistance of FRP-reinforced ECC beams are enhanced compared with their conventional counterparts, particularly with more freeze–thaw cycles. Based on the formulae from ACI 440 and GB 50608, taking into account of the contribution of ECC material and balanced reinforcement ratio, the simplified formulae are developed to estimate the moment capacity and stiffness of the FRP-reinforced ECC beams. The results predicted on the moment capacity and deflection are in good agreement with the corresponding experimental measurements.

An iterative framework is introduced in this present study to detect seismic isolation precursors of the shortcut calculation method for the isolated benchmark high-speed railway RC bridge....

In order to cope with the increasing volume of transportation, many railway bridges are in need of being strengthened especially for the reinforced concrete lightweight pier bridge. An orig...

Experimental and theoretical investigations on the flexural performance of steel reinforced ECC-concrete composite beams subjected to freeze–thaw cycles are presented in this paper. Four groups of reinforced composite beams with different ECC height replacement ratios subject to 0, 50, 100 and 150 cycles of freeze–thaw were physically tested to failure. Experimental results show that the bending capacity decreases with the increase of freeze–thaw cycles regardless of ECC height replacement ratios. However, the ultimate moment, stiffness and durability of ECC specimens and ECC-concrete composite specimens are greater than those of traditional concrete specimens, owing to the excellent tensile performance of ECC materials. With the increase of ECC height, the crack width and average crack spacing gradually decrease. According to materials’ constitutive models, compatibility and equilibrium conditions, three failure modes with two boundary failure conditions are proposed. Simplified formulas for the moment capacity are also developed. The results predicted by the simplified formulas show good agreement with the experimental moment capacity and failure modes. A parametric analysis is conducted to study the influence of strength and height of ECC, amount of reinforcement, concrete strength and cycles of freeze–thaw on moment capacity and curvature ductility of ECC-concrete composite beams.