There is a need to demonstrate how novel timber-concrete composite floors can span long distances and be a practical alternative to other traditional structural systems. Better understanding of the fire behaviour of these hybrid systems is essential. To achieve this, the fire-resistance of a timber-concrete composite floor assembly, using BC wood products, will be evaluated in accordance with CAN/ULC-S101 . A 2 hr fire resistance rating will be targeted, as this is the current requirement in high-rise buildings for floor separations between occupancies.
The structural behaviour of this type of system will also be assessed from conducting pull-out tests of the shear connectors.
In conjunction with previous test data, the results of this test will be used to develop an analytical model to assess the structural and fire-resistance of timber-concrete composite floors.
This project assesses the fire resistance of laminated timber structural systems as wall and floor assemblies. Full-scale tests were conducted to assess structural fire resistance and charring behaviour. This research could be used to expand current fire design provisions and support inclusion of these types of assemblies into Annex B of CSA O86.
Cross-laminated timber (CLT) panels are relatively new engineered wood products that can be used as load bearing walls, floors and roof elements in innovative and high quality modern timber structures. The fire behavior of cross-laminated timber panels requires careful evaluation to allow the expansion of CLT elements usage in buildings. A University of British Columbia study has been conducted at the Trees and Timber Institute CNR-IVALSA in San Michele all’Adige, Italy to experimentally evaluate the fire performance of Canadian CLT panels. In total, ten loaded fire tests were performed using standard fire curves (ULC/ASTM and ISO) to study the influence of different cross-section layups on the fire resistance of floor and wall elements and to investigate the influence of different anchors on the fire behavior of wall elements. This paper presents the main results of the experimental analyses and discusses in particular the charring rate, one of the main parameters in fire design.
Fire-testing data, such as charring rates and failure modes of structural elements exposed to ISO-standard fires, for unprotected cross-laminated timber (CLT) panels made of domestic timber were investigated to apply the reduced-cross-section method to CLT panels. For the charring rates, a series of fire tests without loading was conducted...
A set of novel structural fire tests on axially loaded cross-laminated timber (CLT) compression elements (walls), locally exposed to thermal radiation sufficient to cause sustained flaming combustion, are presented and discussed. Test specimens were subjected to a sustained compressive load, equivalent to 10 % or 20 % of their nominal ambient axial compressive capacity. The walls were then locally exposed to a nominal constant incident heat flux of 50 kW/m2 over their mid height area until failure occurred. The axial and lateral deformations of the walls were measured and compared against predictions calculated using a finite Bernoulli beam element analysis, to shed light on the fundamental mechanics and needs for rational structural design of CLT compression elements in fire. For the walls tested herein, failure at both ambient and elevated temperature was due to global buckling. At high temperature failure results from excessive lateral deflections and second order flexural effects due to reductions the walls’ effective crosssection and flexural rigidity, as well as a shift of the effective neutral axis in bending during fire. Measured average one-dimensional charring rates ranged between 0.82 and 1.0 mm/min in these tests. As expected, the lamellae configuration greatly influenced the walls’ deformation responses and times to failure; with 3- ply walls failing earlier than those with 5-plies. The walls’ deformation response during heating suggests that, if a conventional reduced cross section method (RCSM), zero strength layer analysis were undertaken, the required zero strength layer depths would range between 15.2 mm and 21.8 mm. Deflection paths further suggest that the concept of a zero strength layer is inadequate for properly capturing the mechanical response of fire-exposed CLT compression elements.
Use of structural composite lumber products is increasing. In applications requiring a fire resistance rating, calculation procedures are used to obtain the fire resistance rating of exposed structural wood products. A critical factor in the calculation procedures is char rate for ASTM E 119 fire exposure. In this study, we tested 14 structural composite lumber products to determine char rate when subjected to the fire exposure of the standard fire resistance test. Char rate tests on 10 of the composite lumber products were also conducted in an intermediate-scale horizontal furnace. The National Design Specification/Technical Report 10 design procedure for calculating fire resistance ratings of exposed wood members can be used to predict failure times for members loaded in tension. Thirteen tests were conducted in which composite lumber products were loaded in tension as they were subjected to the standard fire exposure of ASTM E 119. Charring rates, observed failure times in tension tests, and deviations from predicted failure times of the structural composite lumber products were within expected range of results for sawn lumber and glued laminated timbers.
This thesis studies the fire behaviour of Cross Laminated Timber (CLT) panels in partially protected rooms. A one-dimensional heat transfer model was developed to determine the fire resistance of CLT floor and wall panels. During this study, three room fire tests were conducted at Carleton University Fire Research Laboratory to determine the maximum percentage of unprotected CLT surface area that will yield similar results to that of a fully protected room. The rooms had a single opening and were constructed entirely using 3-ply, 105 mm thick CLT panels. A non-standard, parametric fire using furniture and clothing as fuel was used and 2 layers of gypsum board were used to cover the ceiling and the protected walls. The Heat Release Rate, temperature, charring rate and gypsum falloff time of each test was collected. The results obtained from the room test were then compared to the numerical heat transfer model to evaluate its accuracy.
At the Institute of Structural Engineering (IBK) of ETH Zurich, the fire behaviour of timber-concrete composite slabs made with beech laminated veneer lumber (LVL) (BauBuche) was investigated. This composite slab is made of a thin plate (depth: 40 mm or 80 mm) using beech LVL and a concrete layer on top (depth: 160 mm or 120 mm). The beech plate acts both as formwork and as tensile reinforcement. This innovative slab system was implemented for the first time in the ETH House of Natural Resources at ETH Zurich. This paper summarizes the results of two largescale fire tests on loaded timber-concrete composite slabs exposed to standard ISO fire. Both fire tests show that the timber-concrete composite slab using beech LVL reaches sufficient fire resistance and integrity for 90 min and 60 min, respectively.