ABSTRACT
The rotational angles and expansion displacements at girder ends of cable-stayed bridges under thermal variation and trains are so remarkable that they could affect the serviceability of the track structures and even endanger running safety of the trains.
Reasonable track-bridge interaction (TBI) analysis is required to find good solutions for these problems. However, former investigations usually ignored the effect of loading history of various loads, leading to investment waste. It is a common practice to install rail expansion devices on cable-stayed bridges with continuously welded rails (CWRs).
This paper presents a finite element (FE) model based on a cable-stayed bridge on Shanghai metro line, employing both the conventional linear superposition method and the more realistic loading history approach. A loading history approach used in TBI analysis is introduced, in which a double-spring model is employed to simulate the resistance change in the connection elements in different loading cases. A case study is conducted to establish the numerical models of a 300-m cable-stayed bridge and a seven-span simply supported approach on each side associated with the track structure applying both the loading history approach and conventional method to investigate the difference between the two calculation methods. And the structure responses were checked according to various design criteria to determine the necessity of rail expansion device.
Considerable differences are found in the results of the two calculation methods on the relative track-bridge displacements and the relative longitudinal displacements between beam ends due to braking. The rail strength analyzed via more realistic loading history approach is sufficient according to the more reasonable Chinese code. And the check on additional rail stresses tends to be too conservative. The controlling factor for this cable-stayed bridge lies in the longitudinal displacements at beam ends due to bending. Schematic planar model using the FE method (a) the conventional TBI analysis; (b) the proposed TBI model allowing for loading-history effects. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig313_1.tif"/> Overall rail stresses obtained using the loading history approach and conventional method. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig313_2.tif"/>
