The Earthquake Engineering Online Archive

Strength of timber roof connections subjected to cyclic loads

Gülkan, Polat; Mayes, Ronald L.; Clough, Ray W.

UCB/EERC-78/17, Earthquake Engineering Research Center, University of California, Berkeley, 1978-09-01, 131 pages (515/G85/1978)

This report examines the behavior of typical timber roof connections used in single-story masonry residential construction subjected to cyclic loads. In order to assess the adequacy of connections in transferring roof inertia loads developed during earthquake ground motions, five basic types of roof-to-masonry wall connection mock-ups comprising a total of 19 models were subjected to displacement controlled load tests using both in-plane (along the wall) and out-of-plane (transverse to wall) forces. The five types of connections contained load bearing and non-load bearing connection details of both gabled truss and flat roof construction. Behavior of the connections is described in terms of the deformations of the various components comprising the assembly. By examining the mode of failure and the code-allowable loads on bolted and nailed connections, the margin of safety inherent in current code requirements is determined. From the test results, it appears that the connection of the truss rafters to bearing and non-bearing walls, as implemented in the program, is adequate. However, for connections employing ledgers, supplementary anchorage devices need to be used since bolts tend to fail by pulling out of the face shell of the masonry units and ledgers fail easily when subjected to cross grain tension.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-78-17.pdf (35 MB)