Vibrational Modal Frequencies and Shapes of Two-Span Continuous Timber Flooring Systems

Based on classic vibrational bending theory on beams, this paper provides comprehensive analytical formulae for dynamic characteristics of two equal span continuous timber flooring systems, including frequency equations, modal frequencies, and modal shapes. Four practical boundary conditions are considered for end supports, including free, sliding, pinned, and fixed boundaries, and a total of sixteen combinations of flooring systems are created. The deductions of analytical formulae are also expanded to two unequal span continuous flooring systems with pinned end supports, and empirical equations for obtaining the fundamental frequency are proposed. The acquired analytical equations for vibrational characteristics can be applied for practical design of two-span continuous flooring systems. Two practical design examples are provided as well

Dynamic serviceability design of attic room floors in modern timber frame houses

In this paper, the vibrational performance of roof trusses for constructing the attic room floors with various geometric configurations was investigated using commercial finite element software – SAP2000. Vibrational parameters included the mid-span deflections of the bottom chord under dead loads and unit point load, and modal frequencies up to 40 Hz and modal shapes. This study confirmed that increasing the bottom chord size and including composite bottom chord and fully composite roof truss members could largely enhance the dynamic serviceability performance of the attic room floors in timber frame houses