Floor vibration, although not a safety concern, is a prevalent performance complaint in multi-story structures. With the increasing use of mass timber construction, various types of long-span timber floors (LSTFs), including plain cross-laminated timber (CLT), CLT with secondary beams (ribbed-deck), and hybrid systems such as timber–concrete composite (TCC) and CLT on-steel-support beams, are gaining popularity. However, due to limited knowledge regarding their vibration characteristics and acceptance criteria, these construction types are often overlooked during the design stage by architects, engineers, and builders. Existing standards and guidelines primarily calibrated for steel and concrete floors lack a validated and calibrated method for evaluating the vibration performance of LSTFs. Nonetheless, it is essential for structural engineers to address vibration concerns during the design stage and potentially investigate excessive vibration in existing buildings, providing mitigation solutions. This article provides a comprehensive overview, discussion, and analysis of the measurement, analysis, design, perception, and acceptability of vibration of timber floors as outlined in international standards and commonly used guidelines. Experimental and theoretical case studies, including vibration measurements of a CLT floor and a comparison of vibration acceptability in lightweight timber floors using different methods, are reported. The results highlight discrepancies between simplified equation calculations and modal analysis observations, underscoring the limitations of relying solely on simplified equations. Furthermore, it is observed that current modal superposition methods tend to be conservative in predicting floor acceleration and velocity responses. Recommendations are provided for future research in the field to enhance floor vibration assessment techniques, aiming for improved design optimization and occupant comfort.

To be commercialised, glued laminated timber must typically conform to a strict bond integrity assessment. While the associated testing protocols vary slightly from standard to standard, the general method consists of a series of swelling (water immersion) and shrinkage (drying) cycles. The approach is independent of the species and adhesive type. Those cycles strain the gluelines to a level depending on the species’ moisture uptake, timber dimensional movement and modulus of elasticity, as well as adhesive layer elasticity. High density and high modulus of elasticity materials frequently fail within the glueline regions rather than within the timber and therefore fail the bond integrity assessment. To better understand the mechanisms that lead to glueline failure, glulam samples were manufactured using three prominent Australian commercial timbers of various densities (Radiata pine—Pinus radiata, Southern pine—Pinus caribaea/Pinus elliottii, and Spotted gum—Corymbia citriodora) and two structural adhesive types (resorcinol formaldehyde and polyurethane). Using advanced measurement techniques (digital image correlation and strain gauges), the response of the different species and adhesive types to moisture swelling and shrinkage, as well as times at which glueline separation occurs, were captured. A relationship was observed between moisture uptake and delamination percentages with spotted gum producing significantly higher levels of delamination and significantly lower moisture uptake values, compared to both Radiata pine and Southern pine. While the polyurethane glued samples on average produced higher levels of delamination, the digital image correlation data indicates that the time at which this delamination occurs is later than the samples glued with resorcinol formaldehyde.

Finger jointing has long been a method of extending the longitudinal span of short-length timber pieces through a tooth-like profile of a nominated length and bonded with adhesive. With the high-density hardwood resource in the sub-tropics, local industries have found it difficult to obtain adequate bond integrity for high moisture areas and outdoor applications, where a good bond is governed by the dry modulus of rupture (MOR) and the percentage of wood fibre present in the separated joint after exposure to water impregnation. This paper presents the finger joint performance in terms of MOR, stiffness (MOE), and wood fiber amount (WFA) under different variables, joint profile (10 and 20 mm long fingers) using two structurally rated adhesives (a single-component polyurethane (1C-PUR) and resorcinol formaldehyde (RF)) on spotted gum (Corymbia citriodora) and Darwin stringybark (Eucalyptus tetrodonta) jointed boards. Dry bending strength or MOR testing indicated the 20 mm joints with the PUR adhesive had the best performance across both tested species compared to the RF adhesive. The measured MOE of the joints showed the RF samples to have higher MOE (7% to 13%) than the PUR samples for both joint sizes and species. Testing of joint durability through water impregnation resulted in MOR and MOE values decreasing by up to 50% for the RF and PUR joints. Conversely, the performance of water-impregnated joints after being allowed to re-condition to a 12% equilibrium moisture content produced a regain of MOR for the PUR joints across both species of 30% to 40%. Furthermore, it was found that the WFA increased for the PUR samples between the water-impregnated samples and the re-conditioned samples.

Cross-laminated timber (CLT) panels are commonly used in mass-timber multistorey constructions due to their prefabrication, construction flexibility, environmental credentials and weight-to-strength ratio advantages compared to competing building materials. However, the long-term durability and service life of these mass timber panels require further understanding of their performance when exposed to free water. Wetting and drying trials were conducted by exposing Radiata pine (Pinus radiata) CLT sections to either free water (pooling on a single surface) or submerged water (all directions exposed) saturation, followed by either ambient or fan drying. The panels exposed to water pooling only reached MC above the FSP up to 40 mm of the panel depth. For submerged panels, the MC reached values above the fibre saturation point (FSP) at depths of 30 to 40 mm penetration on both panel faces. When comparing the ambient and fan-drying panel sections over the same time period, a less uniform MC profile was observed for the ambient drying, whereas the fan-dried panels fell below the FSP faster and with a more consistent MC profile. A complementary study was conducted on a standalone 3.0 × 3.0 m CLT room, where the room was wetted during a simulated pipe burst event. The moisture monitoring of wall and floor panels during fan drying of the room showed that an MC reduction from an excess of 40% to below 20% could be reached in less than 96 h for the panels’ surface; however, the middle sections of the panels dried slower than the surface sections. The CLT structure fan drying required a longer drying time than the CLT sections tested due to the closed sections (overlaps and connected faces) and a lower rate of airflow. The study of drying CLT sections highlighted the product reaching and maintaining MC higher than FSP points and the need for further drying applied to minimise long-term decay development. Further study is recommended to investigate the effects of closed sections (connected faces) and the duration of drying needed for semi-finished and finished buildings.

This paper presents an investigation on the influence of various factors on rolling shear (RS) properties of timber feedstock for cross laminated timber (CLT) available from Australian plantation forest resources. Comparison of RS properties between three softwood species namely southern pine, radiata pine and hoop pine are presented. Furthermore, the effect of modulus of elasticity (MOE), equilibrium moisture content (EMC), aspect ratio, knots and projection length on rolling shear behaviour were investigated. Mean RS modulus for radiata pine, southern pine and hoop pine samples were 74.7 MPa, 87.1 MPa and 99.7 MPa, whilst the RS strength of those species were 2.6 MPa, 3.1 MPa and 3.7 MPa, respectively. Radiata pine samples exhibited the lowest values for RS modulus and strength, almost 30% less than those of hoop pine samples. The study confirmed that the density and MOE had a very weak correlation with RS properties for all pine species. There was an obvious decrease in RS modulus (by 18%) when the woods’ conditioned EMC changed from 8% to 12%. A further 33% decrease was observed when the woods’ conditioned EMC increased from 12% to 16%. However, the percentage increase in RS strength was found to be 23% higher in wood with 12% conditioned EMC while compared against wood conditioned to 16% EMC. RS strength improved with increased aspect ratio; however, RS modulus remained almost unaffected. Moreover, the projection length that resulted in the load passing through the centroid of the specimen resulted in lower RS modulus values, but the presence of knots improved both RS strength and modulus for all three tested species.

Transverse modal analysis of timber panels is a proven effective alternative method for approximating a material's elastic constants. Specific testing configurations, such as boundary conditions (BC) and location of sensor and impact, play a critical role in the accuracy of the results obtained from the experimental assessment. This article investigates signal-specific details, such as the signal quality factor, that directly relate to the damping properties and internal friction as well as frequency shifting obtained from six different BCs. A freely supported (FFFF), opposing minor sides (shorter length) simply supported, and major sides (longest length) free (SFSF), as well as the reverse of the SFSF configuration with minor sides free and major lengths simply supported (FSFS) and all sides simply supported (SSSS) setup, are investigated. Variations into the proposed methods used to achieve an FFFF supported system are also considered. A combination of experimental testing in parallel with finite element analysis was conducted to re-create the setup that would be used within a manufacturing facility for nondestructive assessment of full-size cross-laminated timber panels. The differences between all BC configurations for their resonance frequency quality and location indicate that a freely supported system provides higher-resolution results, good comparison of less than 10 percent error with the finite element analysis and experimental results, and advantages in a simple experimental setup for the intended application.