摘要: |
The technique of rejuvenating wood and timber members by shear spiking (vertically inserting fiberglass reinforced polymer rods into deteriorated members) evolved over several years of laboratory research at Colorado State University (CSU). Specimens, including layered or split nominal 2 x 4 members, full-scale wood railroad ties, intentionally damaged individual railroad bridge stringers, a full-scale three span bridge chord, and deteriorated/damaged bridge stringers and chords obtained from the field were successfully enhanced in stiffness by the application. The successful stiffening of such members in the laboratory led to the need to examine the application of the technique in actual bridges in the field. This report details the outcomes of shear spiking two open-deck, timber trestle railroad bridges and examining the effectiveness under applied loading. The bridges were made available to the researchers by the Union Pacific Railroad and were located in their Southern Region. The first site was located in the vicinity of Houston, Texas, specifically in Eagle Lake a region of typically hot, humid climate, albeit being cool, damp, and sometimes rainy, conditions at the time of the study. The second site was located in the vicinity of Midland, Texas, specifically Stanton, Texas in an extremely hot, dry climate at the time of the study. Each bridge was multi-span, but only one span was shear spiked in each case. Also, each was located along an in-service mainline railroad track and, due to rated physical condition, were scheduled to have their stringers replaced, making them available for experimentation but on a relatively fast-fuse basis. |