This project aims to support the construction of tall wood buildings by identifying encapsulation methods that provide adequate protection of mass timber elements; the intention is that these methods could potentially be applied to mass timber elements so that the overall assembly could achive a 2 h fire resistance rating.
The superior fire performance of timber can be attributed to the charring effect of wood. As wood members are exposed to fire, an insulating char layer is formed that protects the core of the section. Thus, beams and columns can be designed so that a sufficient cross section of wood remains to sustain the design loads for the required duration of fire exposure. A standard fire exposure is used for design purposes. In North America, this exposure is described in the standard fire resistance test ASTM E 119 [2]. Many other countries use a comparable test exposure found in ISO 834 [3]. In spite of the difference between standard dire resistance tests, experimental charring rates measured in various parts of the world appear to be consistent. This justifies the use of such data for design, regardless of origin.
There has been no research to date exploring whether timber products can provide effective thermal capacitance in residential or commercial construction. This research is exploring the use of unique mass-timber products to provide a new form of thermal performance capacitance
within the built fabric of new and existing homes. The development of mass timber products is a new paradigm in material and building science research in Australia, requiring the accounting for carbon emissions, carbon sequestration, material embodied energy and material thermal properties for this renewable resource. This paper focuses on the results from preliminary building simulation studies encompassing house energy rating simulations and a comparative analysis of embodied energy and carbon storage for a series of house plans in Australia.
International Conference on Performance-based and Life-cycle Structural Engineering
Research Status
Complete
Notes
December 9-11, 2015, Brisbane, Australia
Summary
Tall timber building designs have utilized cross-laminated timber (CLT) significantly over the past decade due the sustainable nature of timber and the many advantages of using an engineered mass timber product. Several design methods have been established to account for the composite action between the orthogonally adhered timber plies. These methods assume perfect bonding of the adjacent plies by the adhesive. CLT designs methods for timber in fire have also been formulated. These methods rely on the relatively constant charring rate of timber to calculate a sacrificial layer to be added onto the cross-sectional area. While these methods focus on the timber failure mode of reduced cross section by charring, the failure mode of ply delamination is often overlooked and understudied. Due to the reduction of shear and normal strength in the adhesive, the perfect bond assumption can be questioned and a deeper look into the mechanics of CLT composite action and interfacial stress needs be conducted. This paper seeks to highlight the various design methods for CLT design and identify the failure mode of delamination not present in the current design codes.
Figure 1 shows a floor plan and elevation along with the preliminary shear wall locations for a sixstorey wood-frame building. It is assumed some preliminary calculations have been provided to determine the approximate length of wall required to resist t...
The paper examines the behaviour of structural timber members subjected to axial compression or combined axial compression and bending. Based on experimental and numerical investigations, the accuracy of the existing approach in Eurocode 5 for the design of timber members subjected to axial compression or combined axial compression and bending is assessed and modifications are suggested. By means of extensive experimental investigations, a data base was created for the validation of calculation models and for the assessment of design concepts. In order to assess the behaviour of timber members subjected to axial compression or combined axial compression and bending, strain-based calculation models were developed.
The investigations indicate that the existing approach of Eurocode 5 based on 2nd order analysis can lead to an overestimation of the load-bearing capacity. Hence, a modified design approach was developed which agrees with the results of the Monte Carlo simulations very well and thus ensures a safe and economical design of timber members subjected to compression or combined compression and bending.
During the last few years, the merging of timber building tradition with the application of new
technologies has produced new prefabricated building systems in Europe and North America. Mid-rise buildings present a unique opportunity to apply new timber technologies. Chile has shown sustained growth of buildings construction during the past decades but little further
development in the use of wood. To establish the feasibility of timber systems applied to the Chilean context this research considered social aspects, technical aspects and local standards related to the manufacture and construction using timber components. A project proposal is used to analyze the architectural applications of timber systems according to the Chilean context. The design considers the case of densification in the city of Santiago and investigates the possibility of developing mid-rise structures using the structural properties and features of timber systems. So far only two systems applied to mid-rise structures have been tested for seismic resistance on full scale prototypes: Midply and Cross Laminated Timber.
