Laboratory Investigation of Steel Tie Performance

UTK Project Information


NuRail Project IDNURail2013-UTK-R07
Project TitleLaboratory Investigation of Steel Tie Performance
UniversityUniversity of Tennessee at Knoxville
Project ManagerDave Clarke
Principal InvestigatorBaoshan Huang
PI Contact Information
Funding Source(s) and Amounts Provided (by each agency or organization)$80,000 NURail Funding; $48,000 R01-1334-323; $32,000 R01-1313-233
Total Project Cost$160,000
Agency ID or Contract NumberDTRT13-G-UTC52 (Grant 2)
Start Date2014-01-01
End Date2017-08-31
Location
Brief Description of Research ProjectThe objectives of the proposed research is to utilize the test pit (9m  9m, located in the UTK CEE department John Tickle Engineering Building) to (1) investigate into the performance of steel railway crossties in conjunction with different ballasts and (2) to explore ways to improve steel tie performance and to reduce track maintenance cost.Crossties are a very important component of conventional railway track structure. They hold rails to the correct gage (i.e., distance apart), maintain rail surface and alignment, and transfer loads from the rails into the ballast. There are three predominant crosstie material types: timber; precast, pre-stressed concrete;and steel. Steel crossties are gaining acceptance due to (1) promise of a longer service life compared with timber, (2) comparable purchase cost to timber and less than concrete, (3) ease of transport and distribution, (4) recyclability and environmental friendliness, (5) stiffness compatibility with timber; and (6) resistance to gage widening forces. However, steel crossties need special tamping to ensure good contact between tie and ballast, leading to higher installation and possibly maintenance cost than the other two ties. Steel is also susceptible to corrosion. Finally, the impact of increased tie contact pressures on ballast life is unquantified at present.In the proposed research, multiple combinations of steel ties with different ballasts will be evaluated in the laboratory test pit. The tests will simulate the traffic loading and real track environment in a realistic manner. The tests will focus on determining the optimal ballast gradation to improve contact between tie and ballast. In the meantime, numerical models utilizing discrete element method (DEM) or finite element method (FEM) will be developed to analyze the deterioration of ballast under steel crosstie loading and to verify and explain the results and findings from the laboratory tests.
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