Strength Capacities and Behavior of New Composite Timber-Steel Connector

Abstract

This paper examines the strength properties of a new timber connector that consists of a sectioned steel tube embedded into the end grain of heavy-timber structural members using a vinyl-ester based mortar. The steel cap of the connector features a threaded hole that allows for the attachment of a variety of connecting steel elements. Connectors were tested in tension and compression in spruce glulam and in tension in parallel strand lumber. Lateral loading tests were performed on single and double connector arrangements with different edge distances and member sizes using spruce glulam members. An additional test series was conducted on specimens exposed to changing climatic environments over a period of 18 weeks prior to tension tests. Results of the tension and compression tests showed a low variation in strength and stiffness. Tension specimens showed an abrupt and brittle failure, indicating the requirement for a more controlled and ductile steel-element failure. Ductile behavior was observed in the compression tests resulting from the deformation characteristics of the wood. In addition, the connection showed a small reduction in strength after the climate cycles. A relationship between edge distance and lateral load capacity was established.