Dynamic Characteristics of Wood and Gypsum Diaphragms

Wood diaphragms are used in low-rise, wood-framed buildings to resist the lateral forces produced by wind and earthquakes. Since wood buildings are known to be efficient in absorbing the energy produced by these loadings, it is of importance to more fully understand the dynamic behavior of their components. Presented in this paper are the results from an experimental study performed to measure the dynamic characteristics of ten plywood and gypsumboard-sheathed diaphragms. Four walls, three floors, and three ceilings were tested to determine natural frequencies and damping ratios. Results indicate that natural frequencies for the diaphragms proportions tested range from 8-29 Hz and vary depending on diaphragm displacement level. Using results of regression analysis, natural frequencies for various diaphragms may be predicted. Damping ratios were calculated and were found to range from 0.09-0.34.