Cross-laminated Timber Floor Research Articles

Cross laminated timber elements in contemporary timber structures of buildings: Application and design

This work analyses cross laminated timber (CLT), contemporary building material produced of dried wooden elements - laminates. Laminates in CLT panels are equally wide and timber fibers are rectangularly plated within layers. Paper shows basic physical - mechanical characteristics of CLT panels and analytic models that are most commonly used in designing of CLT floor and wall construction elements. Advantages and disadvantages of this new construction system are stated according to contemporary requirements in designing environmentally and ecologically acceptable constructions.

Fire Tests on Loaded Cross-laminated Timber Wall and Floor Elements

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.

Prediction of bending stiffness and moment carrying capacity of sugi cross-laminated timber

Cross-laminated timber (CLT) panels consist of several layers of lumber stacked crosswise and glued together on their faces. Prototype sugi CLT floor panels were manufactured and bending tests were carried out under the different parameters of lumber modulus of elasticity (MOE), number of layers, thickness of lumber and thickness of CLT panels. On the basis of above tests, bending stiffness and moment carrying capacity were predicted by Monte Carlo method. MOE of lumber was measured by using grading machine and tensile strength of lumber was assumed to be 60 % of bending strength based on the obtained bending test. Bending stiffness EI of CLT panels could be estimated by adopting composite theory and equivalent section area. Experimental moment carrying capacity showed 12 % higher value than the calculated moment carrying capacity by average lumber failure method, and also showed 45 % higher value than the calculated moment carrying capacity by minimum lumber failure method due to the reinforcement of the outer layer by the neighboring cross layer.

Fire Resistance of Cross-Laminated Timber Panels Loaded Out of Plane

AbstractThis paper describes bending tests at ambient temperature and large-scale fire tests of cross-laminated timber (Xlam) floor panels. Three specimens exposed to standard fire curve were loaded out-of-plane with different levels of uniformly distributed load, and in two cases collapse was reached. Other unloaded panels were protected using different cladding systems with the aim to investigate their thermal behavior. Experimental data obtained from the tests and discussed within the paper includes modulus of elasticity and bending strength at ambient temperature, temperature distribution, charring depth, charring rate, residual cross section, midspan deflection, and time to failure in fire conditions. This data was compared with numerical results obtained by implementing a finite-element model in Abaqus software package for sequential thermal and structural analyses, demonstrating the accuracy of the model. The overall fire performance of the Xlam panels was satisfactory; times to failure of 99 and 1...

Numerical Investigation of the Fire Resistance of Protected Cross-Laminated Timber Floor Panels

Several experimental investigations have been performed on timber elements to determine their fire resistance. However, the numerical modelling is nowadays an effective and inexpensive alternative method to investigate the behaviour of timber structures during fire. Once validated on experimental data, finite element models can be used to understand more in detail the experimental behaviour and then used to carry out parametric studies in which geometrical, mechanical and thermal properties are varied.After an extensive discussion on the state of the art in numerical modelling of timber members and connections during fire, the paper presents a two- dimensional model implemented in the ABAQUS software package to simulate fire tests of cross-laminated timber (XLAM) floor panels protected with different cladding systems. The temperature distribution within the XLAM cross section and the fire resistance of panels loaded out of plane were predicted through thermal and thermo-mechanical analyses, respectively. Since the stiffness and strength degradation of wood with temperature is still a subject of research, a parametric study with different degradation laws was conducted. Numerical predictions were compared with experimental results showing acceptable accuracy, particularly when the degradation laws of the EN 1995-1-2 were used. The comparisons also show the need to model correctly the failure of the protective cladding for an accurate prediction of the thermal behaviour.

Constitutive equations for engineering materials

The Cross-Laminated Timber (CLT) concrete composite floor can successfully address the issues of conventional wood product and become an attractive alternative material for conventional reinforced concrete floors in mid to high-rise building. The purpose of this research was to fully evaluate the capacity of this novel hybrid composite material under both dynamic and static conditions, before such this hybrid system becomes widely employed. This was achieved by performing a full-scale testing of five floor specimens. One specimen was designed according to Eurocode 5 to satisfy the design load for common office buildings, and four specimens were prepared with a concrete topping with different connector types, connector angles, and connector spacing. The test results illustrated that the CLT–concrete floor specimens had excellent structural performance in terms of strength capacity, 3 –5 times higher than the conventional CLT floor. The vibration performances of this composite floors were also enhanced, resulting in a remarkably effective use of this innovative materials.