MPC Research Reports
Report Details

Title:	Composite Repair of Full-Scale Timber Bridge Chord Members through the Process of Shear Spiking
Authors:	Travis Burgers, Richard Gutkowski, Donald Radford, and Jeno Balogh
University:	Colorado State University
Publication Date:	Dec 2005
Report #:	MPC-05-173
Project #:	MPC-249
TRID #:	01030697
Keywords:	bridge members, degradation (thermodynamics), epoxy resins, fiberglass, flexural strength, glass fiber reinforced plastics, load tests, polymers, railroad bridges, reinforcement (engineering), shear reinforcement, shear strength, spikes, stiffness

Abstract

Investigations into the effects of the addition of vertically-oriented shear spikes with fiberglass reinforced polymer rods have shown that the shear spikes increased the effective stiffness of the stringers of a full-scale timber bridge chord specimen. This was previously found to be true on dimension lumber and medium-sized timber. This report presents the results found from the flexural load testing of a full-scale timber bridge chord laboratory specimen. The bridge chord specimen was intentionally damaged to simulate degradation. Reinforcement was provided with 19 mm (3/4-inch) diameter fiberglass reinforced polymer shear spikes bonded to the wood by an epoxy resin. Shear spikes were installed in pairs vertically from the top of the member into pre drilled holes to provide horizontal shear resistance and to improve the flexural effective stiffness. Results from the testing showed that with the insertion of five sets of shear spikes an average effective stiffness of 91.6 percent was recovered in the four stringers of the chord.