Effects of material uncertainties on vibration performance of cross laminated timber floors

Abstract

Variety of wood species and complexity of their structure make the reliable material properties of cross-laminated timber (CLT) difficult to obtain, which can lead to inaccurate prediction of CLT behavior. Due to high stiffness-to-weight ratio, CLT floors can suffer from vibration serviceability issues. This paper aims to quantify the uncertainties induced by material properties and investigate their effect on vibration performance of CLT floors. Analysis based on Monte Carlo simulations, considering material properties as random variables, is developed. Based on the conducted analysis, appropriate conclusions have been derived.

Evaluating Laboratory Measurements for Sound Insulation of Cross-Laminated Timber (CLT) Floors: Configurations in Lightweight Buildings

“…Such discrepancies in acoustic performance can be easily explained though. Deviations may occur between CLT floors of similar type and thickness considering variations in the wood type as a raw material [21,31,42]. Changes in wood material have a high probability of shifting eigenfrequencies [43], which can consequently affect the sound insulation results in 1/3 octave bands.…”

“…It utilizes full configurations, as combined materials, hence specific material behavior is not analyzed extensively. Secondly, it employs a single CLT floor component, without testing other similar samples for deviations that are reported to be significant [21,32]. Further, laboratory measurements record the insulation performance of the tested sample, while in situ measurements take into account flanking transmission and the interactions of the surrounding structure [13,34,38].…”

“…Thus, the obligatory limit from 100 Hz in ISO 717 −1 and −2 [19,20] is under debate. The same applies to regulations, threshold values, and the lack of harmonization [15,21], while in Nordic countries, the extended frequency range from 50 Hz has been adopted [22].…”

“…However, limited measurement data for sound insulation of massive CLT floors have been published and no reliable prediction models for sound transmission in CLT structures have been found [2,3,5,10,25]. Although several approaches for modeling sound insulation of CLT floors have been developed, including analytical models [8,11,26], finite element methods [4,21,27,28], wave propagation modeling [26], statistical energy analysis [25], and modeling with neural networks [29], to estimate the acoustic performance of CLT floors, acousticians still rely on field or laboratory measurements, which still provide only indications [3,8,10,21].…”

“…Moreover, reference data are provided for concrete or wooden joist floors in ISO 10140-5 [30], but not for massive CLT floors, while this necessity has been reported [9,31]. This problem amplifies considering variations between the similar sample structures from different wood types (base material), manufacturers, and productions [21,32]. There is also limited characterization with acoustic descriptors for CLT components, while studies focus mostly on structural behavior [25,33].…”