ABSTRACT
The rail–bridge interaction is an important parameter in railway bridge design. Therefore, measurement campaign together with nonlinear model calibration was performed to investigate the interaction process and for prediction of longitudinal stress in the rail and the concrete slab track. The longitudinal stress of continuously welded rails (CWR) needs to be controlled. Stress in rail is caused by the temperature changes in rail, bending of the bridge deck, braking and acceleration of trains and also by temperature changes in bridge transferred via rail–bridge interaction. An essential parameter for quantifying the effects of the interaction between rail and substructure is the free expansion length of the bridge, defined as the distance between the thermal reference point and the flexible end point of the supporting structure.
For investigation of rail–bridge interaction and for prediction of longitudinal stress in the rail due to temperature loading a nonlinear FEM model of L110 bridge in Austria has been developed and calibrated with respect to experimental measurements and code specifications (see Fig. 1). The whole system has been modeled in ATENA software (Červenka et al. 2007). Detailed spring stiffness calibration based on results of in-situ measurements was carried out. Calibration of the rail clamp for non-ballasted track: a) horizontal loading, b) vertical loading. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig212_1.tif"/>
A numerical study using calibrated model was carried out in order to capture the effect of bridge temperature loading on stress induced in a rail due to track–bridge interaction which should not exceed the admissible stress capacity. Effect of various bridge free lengths for both non-ballasted as well as ballasted track was studied. The temperature of the structure was within the range of 0 and 30°C, and the temperature of the rail was 0, 28 and 50°C. Results show that admissible stress neither in tension (92 MPa for both tracks) nor in compression (72 MPa for ballasted track, see Fig. 2, and 92 MPa for non-ballasted track), was not exceeded for all studied cases. Maximum compressive stress (admissible stress for ballasted track <italic>σ</italic> <sub>compression</sub> = 72 N/mm<sup>2</sup>) in individual parts of the rail for different values of free length <italic>L</italic> – ballasted track. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig212_2.tif"/>
