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Results: 1 - 3 of 3 Z-Spike Rejuvenation to Salvage Timber Railroad Bridge Members (Dec. 2008, MPC-08-208, Project #275) Nathan J. Miller, Richard M. Gutkowski, Jeno Balogh, and Don W. Radford This research study examined the effectiveness of the fiber reinforced polymer (FRP) spikes in repairing naturally damaged and deteriorated railroad bridge chords. Past research has shown that this process can be quite effective in improving the effective stiffness of railroad chord members that were intentionally damaged. This shear spiking process involves inserting the FRP spikes vertically into railroad bridge members. The spikes are held in place by an adhesive and are intended to repair horizontal cracks that develop in the members over the course of their lifespan.
This study included three specimens that were of varying size and damage conditions. In each case, the spiking technique as well as the overall improvement in specimen stiffness was analyzed. This report summarizes the spiking process used in each specimen as well as the results. It was found that the increase in the stiffness of the specimens was highly dependent on the initial condition of the specimens. The last specimen in the study showed the most promising results as it was also the most damaged. The spikes were installed in slightly oversized holes with epoxy resin as the adhesive. This specimen experienced a 267% increase in the initial effective stiffness when loaded to 15 kips. After a test to 39 kips, this increase was reduced to 179%. This result confirms the potential for shear spiking as a highly effective tool for in situ repair of damaged or deteriorated railroad bridge beams. Keywords: fiber composites, railroad bridges, rejuvenate, shear spike, timber  | Integrating Security into Small MPO Planning Activities (Jul. 2008, MPC-08-199, Project #295) Mark Lofgren MPOs are beginning to consider implications of the 2005 Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU) legislation that requires specific attention for security elements in transportation planning. This most recent federal transportation bill extracts and differentiates safety planning and security planning as two distinct elements in MPO planning activities. "Security planning includes activities and products developed in response to identified criminal threats to high value, vulnerable elements of the transportation system" (Federal Highway Administration 2006). Safety may be distinguished from security, but the two elements are often highly interrelated in the activity scope of smaller MPOs. The difference between the two is that security places an emphasis on being protected from manmade and naturally occurring dangers or hazards. The MPO role in security may take many forms including facilitator, participant, or leader in the security-related activities. In many instances, these security activities may be related to other planning factors such as safety, accessibility, and efficiency. This paper outlines the process for establishing the security element in the long range transportation plan for a bi-state MPO with an urbanized area population of 160,000. Keywords: security, planning, MPO, emergency preparedness | Composite Repair of Full-Scale Timber Bridge Chord Members through the Process of Shear Spiking (Dec. 2005, MPC-05-173, Project #249) Travis Burgers, Richard Gutkowski, Donald Radford, and Jeno Balogh 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. Keywords: fiber composites, shear spike, timber, bridges, railroad, repair  | | | |
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