Support Stiffness and Two-span Continuity Effects on Static Deflection and Fundamental Natural Frequency of Mass Timber Floors

Abstract

Static deflection at mid-span under a concentrated load and fundamental natural frequency are two important vibration serviceability design parameters for mass timber panel (MTP) floor systems. Current design procedures for the two parameters tend to be conservative and over-simplified. To quantify the effects of rotational stiffness of connection, flexural stiffness of supporting beam, and two-span continuity on the two design parameters, an experiment program was conducted on 49 narrow MTP floor panel specimens at University of Alberta. Six analytical expressions are proposed to calculate the static deflection and fundamental natural frequency of two-span floor with restrained connections, one-span floor with restrained connections and supported by beams, and two-span floor with restrained connections and supported by beams. The analytical expressions were verified against the test results and a relatively good agreement was found. Sensitivity analyses were conducted to simplify the analytical expressions. Conclusions were drawn based on the comparisons and discussions. The recommended stiffnesses of supporting beams are proposed to reach satisfactory fundamental natural frequencies for both one-span and two-span floors with varies support conditions.