Semester

Spring

Date of Graduation

2004

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Civil and Environmental Engineering

Committee Chair

Hota V. S. GangaRao.

Abstract

This study involves the rehabilitation and load testing of 50 + year old open deck timber railroad bridges on the South Branch Valley Railroad (SBVR) in Moorefield, WV. The rehabilitation involved repairing substructure elements including a "Pile cap/pile" joint and an above ground pile with Glass Fiber Reinforced Polymer (GFRP) composite wraps, in combination with phenolic formaldehyde adhesives. Static and dynamic testing was performed to determine the dynamic behavior and the live load distribution of the superstructure. This research study is the second phase of a two-phase study with an ultimate objective to investigate the rehabilitation of timber railroad bridges using GFRP composite materials. The rehabilitation associated with Phase I of this research program involved the superstructure and substructure elements also, and had a beneficial affect on the overall performance of the bridge as noted by a 40% reduction in deflection.;Static and dynamic load test data were acquired using an 80-ton locomotive supplied by SBVR. The test results show an improvement in load distribution in the rehabilitated pile bent. Dynamic load allowance (DLA) factors were also obtained and in several cases were found to increase in value with increasing locomotive speed.;To verify bonding capabilities of creosote treated 50+ year old timber with GFRP composite wraps and evaluate the recovery of strength of repaired timber beams, four full scale (8&inches; x 16&inches; x 12&feet;) timber stringers were tested in a controlled laboratory setting in four point bending configuration. Two control specimens were tested to failure in bending. The specimens were then repaired using GFRP composite wraps applied in the area of maximum moment. A second pair of control specimens was also tested to failure in shear, and also repaired using GFRP composite wraps applied in the maximum shear zones. All of the repaired beams were then retested in four point bending. All repaired test specimens showed significant signs of strength regain. The results from testing the creosote treated southern pine beams before and after repair with GFRP are presented.

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