Open AccessUsing Differential Shear Strain Measurements to Monitor Crosstie Support Conditions in Railroad Tracks
Author(s) -
Dani Johnson
Publication year - 2022
Language(s) - English
Resource type - Dissertations/theses
DOI - 10.18122/td/1911/boisestate
Subject(s) - strain gauge , subgrade , structural engineering , ballast , stiffness , shear (geology) , finite element method , differential (mechanical device) , engineering , calibration , geotechnical engineering , geology , physics , electrical engineering , petrology , quantum mechanics , aerospace engineering
This thesis details a comprehensive numerical analysis of load determination, and crosstie support assessment and monitoring using strain gauges to measure differential rail shear strain in ballasted railroad tracks due to applied railcar wheel loads. These differential shear strain measurements can be related to applied wheel loading and crosstie support reactions through the geometric and constitutive properties of a given rail section. The basic theory behind the measurement technique was reviewed and investigated using finite element models of varying complexity. The impact of field conditions such as differential ballast and subgrade support, track stiffness, crosstie spacing, gauge installation location, and circuit calibration methods were explored, as well as the nature of the interaction between vertical and lateral loads on accurate load determination. The results of this theoretical study indicate that differential shear strain measurements are a robust method for load and crosstie support assessment and monitoring and can be used for accurate measurement of both vertical and lateral loads.