Cyclic Testing of Weldable Shear Connectors for Glulam Decks on Bridge Griders

摘要

The overall objective of the research reported was to determine the residual shear strength and stiffness of weldable shear studi-epoxy grout connector system for attaching glulam decks to steel bridge girders after long term (15M cycles) cyclic shear loading. Specific objectives were to determine the load-slip characteristics of the connector system after 15M load cycles and to prepare an appropriate addendum to the Pennsylvania Department of Transportation's BLC-560M, Standard plans for Hardwood Glulam Highway Bridges, based on the measured residual strength and stiffness after 15 M load cycles. Ten test specimens, five with load parallel to the wood grain and five with load perpendicular to the wood grain, were loaded cyclically to 2,200 pounds of shear load. Shear strength and stiffness were measured after one and 15 M cycles of load from static tests on a Universal Testing Machine. Secondary measures of shear stiffness were measured after 1000, 10,000, 100,000, 400,000 1M, 2M, 4M, 6M, 8M, 10M, 12M, 14M and 15M load cycles. One specimen failed prematurely after approximately 6.9 M load cycles. The failure mode for this specimen was combined bending and shear failure of the steel stud due to faulty specimen mounting in the test jig. All other specimens were still sound after 15 M load cycles.