Performance of Drywall Shear Walls: UC Irvine Tests

A wealth of data has become available since 2001 about the performance of drywall shear walls under cyclic loading. Drywalls and stucco are the only earthquake lateral force resisting system in many existing residential buildings, especially single-family homes built in 1970's and earlier. This paper takes a closer look at the actual laboratory cycle by cycle data from two test programs (CoLA-UCI and CUREE W-25 Reports) and uses them to clarify the meaning of significant damage in regards to gypsum sheathed shear walls. This paper can be viewed as an extension of the valuable information in the reports by the original authors with a focus on the interpretation and use of the test data for the evaluation of damage to existing wood-frame buildings. Analysis of the data considers the strength loss observed between the initial and later cycles when the wall is loaded to a certain displacement and shows that a loss of strength does occur. In this regard the paper can also be valuable to others working on performance based design development.