Woodframe Seismic Response Analysis — Benchmarking with Buildings Damaged during the Northridge Earthquake

The 1994 Northridge Earthquake provided the impetus for much research in the field of seismic performance of woodframe residential buildings, resulting, in part, in specialized analytical software and an array of laboratory test data. Utilization of these new tools and data permit detailed analysis of the response of woodframe buildings to any arbitrary ground motion. While the software has been, and continues to be, benchmarked against laboratory studies of particular damage mechanisms (by virtue of design and construction details of the specimens), these tools have not, as yet, been benchmarked against the seismic performance of real woodframe buildings subjected to actual earthquake ground shaking. This paper presents the results of a series of analyses utilizing the new software (SAWS and SAPWood) and laboratory test data (COLA, CUREE-CalTech, CUREE-EDA) to hind cast the performance of two real woodframe buildings with documented damage due to the Northridge Earthquake. Comparison of predicted wall finish damage based on calculated drift estimates to field observations demonstrates that good correlation can be attained if the data and software are used judiciously. Using the analytical software benchmarked to the actual performance of these buildings, the paper also presents results of an analytical evaluation wherein one of the buildings is subjected to suites of ground motions that, on average, represent 10% and 2% probability of exceedance in 50 years for Los Angeles.