Damping Assessment of Lightweight Timber Floors Under Human Walking Excitations

Abstract

Vibrations on timber floors are among the most common serviceability problems in social housing projects. The presence of low damping levels on these floors could cause excessive vibrations in a range of frequency and amplitude that generate discomfort in users. This study focuses on the influence of the damping ratio in the dynamic serviceability of social housing timber floors due to walking excitations. More than 60 human-walking vibration tests were conducted on both laboratory and in-situ timber floors. The floors were instrumented with accelerometers, and fundamental modal damping ratios were estimated by applying Enhanced Frequency Decomposition Domain (EFDD) and Subspace Stochastic Identification (SSI) methods. The vibration dose value (VDV) was used to estimate the dynamic serviceability of floors. The results indicated that timber floors had an impulsive-type vibration response, with fundamental damping ratios between 1.9% and 14.8%, depending on their constructive characteristics. The in-situ floors had damping ratios between two to three times greater than the laboratory floors due to the presence of non-structural elements. Finally, it was possible to demonstrate that the floors with the highest damping ratios reached lower vibration dose values and, therefore, a better dynamic serviceability performance.

Non-Destructive Assessment of the Dynamic Elasticity Modulus of Eucalyptus nitens Timber Boards

“…Previous research [ 32 ] has shown that Operational Modal Analysis (OMA) is useful for estimating the dynamic properties of structural timber elements from vibration response measurements only, both in laboratory and in-situ construction contexts. Over the years, several OMA methods have been developed, classified as parametric and non-parametric.…”

Investigating Vibration Characteristics of Cross-Laminated Timber Panels Made from Fast-Grown Plantation Eucalyptus nitens under Different Support Conditions

“…In residential buildings, vibrations and the consequent noise caused by footsteps are the major source of human discomfort and often manifest as short-term transient oscillations. Hence, several studies have conducted vibration tests of floors by employing real footfalls as the excitation source [23,[25][26][27]. However, assuming that for small-amplitude vibrations the response is linear, the response of the floor to a footfall can be obtained by convolution of the temporal profile of a footfall with the impulse response of the floor.…”

Special Feature Vibration-Based Structural Health Monitoring

“…Probability density functions were used to evaluate the vibration responses. Opazo-Vega et al [7] proposed a experimental method to estimate damping of lightweight timber floors. Damping is an important parameter to be identified accurately.…”