This article presents a test method that was developed to screen adhesive formulations for finger-jointed lumber. The goal was to develop a small-scale test that could be used to predict whether an adhesive would pass a full-scale ASTM E119 wall assembly test. The method involved loading a 38-mm square finger-jointed sample in a four-point bending test inside of an oven with a target sample temperature of 204°C. The deformation (creep) was examined as a function of time. It was found that samples fingerjointed with melamine formaldehyde and phenol resorcinol formaldehyde adhesives had the same creep behavior as solid wood. One-component polyurethane and polyvinyl acetate adhesives could not maintain the load at the target temperature measured middepth of the sample, and several different types of creep behavior were observed before failure. This method showed that the creep performance of the onecomponent adhesives may be quite different than the performance from short-term load deformation curves collected at high temperatures. The importance of creep performance of adhesives in the fire resistance of engineered wood is discussed.
Timber buildings made with Cross-laminated Timber (CLT) panels are becoming wide spread in Europe. The fire resistance of CLT panels depends upon several parameters, including the number of layers and their thickness. At the present, EN 1995-1-2:2004 does not provide specific information on the fire design of CLT panels. Several fire resistance tests of CLT panels were performed in different scales by furnace testing using the standard fire curve according to ISO 834-1:1999, however the large number of possible combination of CLT products makes testing too complicated and expensive as a tool for the verification of the fire resistance of several combinations. In this report are presented nine small-scale tests carried-out at SP Wood Technology (Technical Research Institute of Sweden). The tests consisted in specimens of CLT and massive timber exposed at a two steps of constant heat flux in a cone calorimeter (50 and 75 kW/m2). Some specimens were exposed with two different types of fire protection (gypsum plasterboard type F and plywood) and some were tested unprotected. Later, thermal simulations with the same set-up of tests were implemented on the finite element software package in Safir 2007, with the time-temperature curve given by ISO 834 as input; also the analytical calculation of the charring depth following the Eurocode 5 part 1-2 was done. The target of this thesis is to compare performed CLT furnace tests with the smallscale cone calorimeter tests carried out, the numerical results of the thermal model and the analytical results obtained.
A large-scale fire test was conducted on a compartment constructed from cross laminated timber (CLT). The internal faces of the compartment were lined with non-combustible board, with the exception of one wall and the ceiling where the CLT was exposed directly to the fire inside the compartment. Extinction of the fire occurred without intervention. During the fire test, measurements were made of incident radiant heat flux, gas phase temperature, and in-depth temperature in the CLT. In addition, gas flow velocities and gas phase temperatures at the opening were measured, as well as incident heat fluxes at the facade due to flames and the plume leaving the opening. The fuel load was chosen to be sufficient to attain flashover, to achieve steadystate burning conditions of the exposed CLT, but to minimize the probability of uncertain behaviors induced by the specific characteristics of the CLT. Ventilation conditions were chosen to approximate maximum temperatures within a compartment. Wood cribs were used as fuel and, following decay of the cribs, selfextinction of the exposed CLT rapidly occurred. In parallel with the large-scale test, a small scale study focusing on CLT self-extinction was conducted. This study was used: to establish the range of incident heat fluxes for which self-extinction of the CLT can occur; the duration of exposure after which steady-state burning occurred; and the duration of exposure at which debonding of the CLT could occur. The large-scale test is described, and the results from both the small and large-scale tests are compared. It is found that selfextinction occurred in the large-scale compartment within the range of critical heat fluxes obtained from the small scale tests.
The work presented in this thesis deals with the investigation of the dynamic performance of timber only and TCC flooring systems, which is one of the sub-objectives of the research focus at UTS. In particular, the presented research assesses the dynamic performance of long-span timber and TCC flooring systems using different experimental und numerical test structures. For the experimental investigations, experimental modal testing and analysis is executed to determine the modal parameters (natural frequencies, damping ratios and mode shapes) of various flooring systems. For the numerical investigations, finite element models are calibrated against experimental results, and are utilised for parametric studies for flooring systems of different sizes. Span tables are generated for both timber and TCC flooring systems that can be used in the design of long-span flooring systems to satisfy the serviceability fundamental frequency requirement of 8 Hz or above.
To predict the fundamental frequency of various TCC beams and timber floor modules (beams), five different analytical models are utilised and investigated. To predict the cross-sectional characteristics of TCC systems and to identify the effective flexural stiffness of partially composite beams, the “Gamma method” is utilised.
[...] two novel methods are developed in this thesis that determines the degree of composite action of timber composite flooring systems using only measurements from non-destructive dynamic testing. The core of both methods is the use of an existing mode-shape-based damage detection technique, namely, the Damage Index (DI) method to derive the loss of composite action indices (LCAIs) named as LCAI1 and LCAI2. The DI method utilises modal strain energies derived from mode shape measurements of a flooring system before and after failure of shear connectors. The proposed methods are tested and validated on a numerical and experimental timber composite beam structure consisting of two LVL components (flange and web). To create different degrees of composite action, the beam is tested with different numbers of shear connectors to simulate the failure of connection screws. The results acquired from the proposed dynamic-based method are calibrated to make them comparable to traditional static-based composite action results. It is shown that the two proposed methods can successfully be used for timber composite structures to determine the composite action using only mode shapes measurements from dynamic testing.
Structural solutions involving the mechanical interaction of timber and glass load-bearing members showed a progressive increase in the last decade. Among others, a multipurpose hybrid facade element composed of Cross-Laminated Timber (CLT) members and glass panels interacting by frictional contact mechanisms only was proposed ion the framework of the VETROLIGNUM project. While demonstrating enhanced load-bearing and deformation capacity performances under seismic loads, facade elements are known to represent a building component with multiple performance parameters to satisfy. These include energy efficiency, durability, lightening comfort and optimal thermal performance. In this paper, a special focus is dedicated to the thermal performance assessment of CLT-glass facade modules under ordinary operational conditions. Based on the thermal-chamber analysis of small-scale prototypes, reliable Finite Element numerical models are developed and applied to full-scale VETROLIGNUM solution. Sensitivity analyses are hence carried out to explore the actual thermal performance of these novel hybrid systems.
Timber-Concrete Composite (TCC) systems are comprised of a timber element connected to a concrete slab through a mechanical shear connection. A large number of T-beam configurations currently exist; however, the growing availability of panel-type engineered wood products (EWPs) in North America in combination with a concrete topping has offered designers and engineers greater versatility in terms of architectural expression and structural and building physics performance. The focus of this investigation was to experimentally determine the properties for a range of TCC systems in several EWPs. Strength and stiffness properties were determined for different TCC configurations based on small-scale shear tests. Eighteen floor panels were tested for elastic stiffness under a quasi-static loading protocol and measurements of the dynamic properties were obtained prior to loading to failure. The tests confirmed that calculations according to the -method can predict the basic stiffness and dynamic properties of TCC floors within a reasonable degree of accuracy. Floor capacities were more difficult to predict, however, failure occurred at loads that were between four and ten times serviceability requirements. The research demonstrated that all selected connector configurations produced efficient timber-concrete-composite systems.