A wood-concrete composite deck is presented, where wooden beams are placed in the compression side and the concrete layer is in the tension side. The main motive for this unusual setup is the better fire resistance of the system. The composite system was investigated under fire conditions. Experimental investigations were conducted on a small section of the structure in order to analyze the behaviour of the system. The specimen was subjected to the ISO-834 standard temperature-time curve with the concrete slab exposed to fire. Subsequently, the experiment was modeled using a commercial software package, and a transient thermal analysis was performed with temperature dependent material properties. The temperature profiles for all the materials are adequately comparable from both the investigations, i.e. experimental and numerical. The validated numerical model allows modifying geometrical parameters and determining fire-resistance ratings of different system configurations.
This paper presents an experimental evaluation of the fire resistance of glued-in rod timber joints using epoxy resin, with and without modification. A heat-resistant modified resin was designed by adding inorganic additives into the epoxy resin, aiming to improve the heat resistance. Joints that were made using the modified epoxy resin at room temperature showed a bearing capacity comparable to those with commercial epoxy resin. Twenty-one joint specimens with the modified epoxy resin and six with a commercial epoxy resin were tested in a fire furnace to evaluate the fire resistance. The main failure mode was the pull-out of the rod, which is typical in fire tests of this type of joints. As to the effects of the test parameters, this study considered the effects of adhesive types, sectional sizes, stress levels, and fireproof coatings. The test results showed that the fire resistance period of a joint can be evidently improved by modifying the resin and using the fireproof coating, as the improvements reached 73% and 35%, respectively, compared with the joint specimens with commercial epoxy resin. It was also found that, for all specimens, the fire resistance period decreased with an increase in the stress level and increased with an increase in the sectional sizes.
Glued laminated timber (glulam) is manufactured by gluing and stacking timber lamellas,
which are sawn and finger-jointed parallel to the wood grain direction. This results in a
sustainable and competitive construction material in terms of dimensional versatility and
load-carrying capacity. With the proliferation of glued timber constructions, there is an
increasing concern about safety problems related to adhesive bonding. Delaminations are
caused by manufacturing errors and in service climate variations simultaneously combined
with long-sustained loads (snow, wind and gravel filling on flat roofs). Several recent
building collapses were related to bonding failure, which should be prevented in the future
with a timely defect detection. As an outlook, the feasibility of air-coupled ultrasound tomography was demonstrated with numerical tests and preliminary experiments on glulam. The FDTD wave propagation model was excited by the difference of the time-reversed sound fields transmitted through a test and a reference (defect-free) glulam cross-section. Both datasets were obtained with the same SLT setup. Wave convergences then provided a map of bonding defects along the height and width of the inspected glulam cross-sections. Further
research is envisaged in this direction
The advantages of the two different building construction materials, timber and concrete, can be used effectively in adhesive-bonded timber-concrete composite constructions. The long-term behavior was investigated experimentally on small-scale shear and bond specimens under artificial, alternating climatic conditions and on fullscale specimens under natural climatic conditions for an application in construction practice. The development of the shear strength and the deformation behavior under permanent loads were studied, focusing on the different material behavior of wood and concrete regarding changes in temperature and moisture. The general applicability of adhesivebonded timber-concrete composites in construction practice was proved in the investigations.
The advanced calculation methods for wood structural elements in fire situations proposed by EN1995-1-2 provide reduction factors of wood strength according to the temperature. The values of these reduction factors given for compression and tension strength are relatively well documented. However, the reduction factors of wood shear strength with temperature were not studied. This study concerns experimental investigations conducted to characterize the evolution with temperature of the shear strength of wood. The tests are realized using a specific original specimen specially developed for this study. The experimental results allow evaluating the values given in EN1995-1-2.
The outcomes of an experimental study aimed to investigate the structural behaviour of wood-steel-wood glulam frame moment-resisting connections that were subjected to static bending are presented in this paper. Each frame test assembly was consisted of two glulam beams simply supported at their far ends and were connected to an inversely-loaded...
The concept of combining folded thin steel plates and glued laminated timber in the beam element to gain increased structural and fire performances was developed at the Institute of Structural Design and Timber Engineering (ITI) in Vienna University of Technology...