Seismic Damage Thresholds for Gypsum Wallboard Partition Walls

A series of 11 tests of full-scale partition walls were conducted to determine the behavior of nonstructural gypsum wallboard partition walls during lateral deformation as might be expected during a major earthquake. The partition walls were constructed as double-sided, 1/2 in. (13 mm) gypsum wallboard partition walls with wood stud framing. The walls deformed laterally in one of two ways: either as a joint-failure mode with racking of the individual gypsum wallboard panels, or by a pier-rotation mode where all the gypsum wallboard panels in a pier rotated as a unit. In all of the tests, the fasteners failed by pulling through the back of the wallboard panel, cutting of the gypsum, or tearing out through the edge of a wallboard panel. In some tests, the strength of the tape and compound was seen to provide adequate support to cause the walls to roll as a single unit, especially when the spacing of fasteners was large. The maximum load resisted varied from 512 N/m (378 lb/ft) to 1,177 N/m (869 lb/ft) and occurred at drifts between 0.68 and 1.87%. The drift when specific damage thresholds occurred was monitored during testing. Damage initiated with slight cracking of the panels at the wall opening at drifts of 0.25%, followed by increasing damage up to drifts of 2%, and minimal additional damage at drifts above 2%. Damage thresholds for cyclic loading often occurred at lower drifts than comparable specimens under monotonic loading.