Date of Award

2017

Document Type

Open Access Thesis

Department

Civil and Environmental Engineering

Sub-Department

College of Engineering and Computing

First Advisor

Dimitris Rizos

Abstract

This study focuses on the performance assessment of prestressed concrete railroad ties made of a newly developed High Strength Reduce Modulus (HSRM) concrete. The HSRM material has been developed by researchers at the University of South Carolina laboratories. The HSRM material was originally considered as a high-performance concrete for highway bridge girders, but it was rejected because it shows very low modulus of elasticity. A current project at USC proposed to use this HSRM material in prestressed concrete railroad ties. The experimental tests during the material development phase of the project showed that the HSRM-HPC has a reduced Modulus of elasticity as much as 50 % compared to conventional high strength concrete. The hypothesis is that a more resilient concrete tie will better distribute the loads and delay the initiation of cracking. This work discusses the qualification of the new HSRM concrete tie according to the guidelines of the American Railway and Maintenance of Way Association (AREMA) requirements and assesses its performance by comparing its performance to the equivalent Standard prestressed concrete ties currently in use in order to validate the hypothesis. To this end, a number of prototype HSRM ties and Standard concrete ties have been fabricated at a major US concrete tie manufacturer and tested in the structures laboratories at the University of South Carolina. Conventional instrumentation, as well as state of the art laboratory instrumentation based on vision system, is employed in these studies. Experimental investigations have shown that the newly developed of HSRM ties not only satisfy the requirements of the design guidelines but also have shown superior structural performance to the Standard ties under static and cyclic load tests. The higher flexibility of the HSRM ties leads to normalized stress fields, reduced stress amplitudes in critical areas, and better post cracking performance and ultimate strength as compared to the Standard ties.

Rights

© 2017, Ali Haider Abdulqader

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