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原文传递 Effects of Environmental Exposure on Timber Railroad Bridge/Track Members and Connectors.

题名：	Effects of Environmental Exposure on Timber Railroad Bridge/Track Members and Connectors.
作者：	burgers, t. balogh, j. gutkowski, r.
关键词：	bridges(structures),structural timber,loads(forces),railroad tracks,bridge chords
摘要：	A pilot experimental study examined the time-dependent mechanical effects of moisture, temperature and humidity on a particular connection detail of open-deck timber trestle railroad bridge chord. A full-scale specimen was conceived to include the standard inter-connections of the steel rail to wood cross-tie to multi-ply chord member. The full-scale section of a timber trestle railroad bridge was tested to observe the time-dependent mechanical effects of temperature and humidity on timber trestle railroad bridge connections by analyzing the load-sharing effects of the plies through the transverse connector rods. The three-ply test specimen was built using full-scale members. The specimen spanned 67 inches and was composed of seven wood crossties. It was ramp tested on each of its three plies and vertical displacement measurements were taken. The test specimen was then subjected to changes in temperature and humidity in an environmental chamber and then it was ramp tested again. The results of the test were unexpected as the midspan deflection of the east ply increased 82 percent while its load increased 1.1 percent; the midspan deflection of the west ply increased by 7 percent while its load decreased 0.8 percent. Despite the changes in deflection, the load sharing through the plies remained nearly unchanged.
报告类型：	科技报告