Wood floor vibrational performance as affected by MSR vs. VSR lumber E-distribution

A simulation study was conducted to investigate the effect of the coefficie nt of variation of the modulus of elasticity (Omega(E)) on the predicted vi brational performance of joist floor systems. Four floor cases were studied and two types of lumber were considered: MSR and VSR lumber where Omega(E) is 0.11 and 0.25, respectively, as defined by the National Design Specific ation (NDS) (1). The predicted floor vibrational performance of MSR versus VSR lumber joists with and without load sharing included in the analyses wa s evaluated by: 1) the probability that the fundamental frequency is less t han 10 Hz; and 2) the ratio of the first percentile of predicted fundamenta l frequency of MSR to VSR lumber. Overall, MSR lumber (Omega(E) = 0.11) flo or systems exhibited improved predicted vibrational performance over VSR fl oor systems (Omega(E) = 0.25) based on the two measures of floor performanc e studied.