Jana Daňková

Stiffness analysis of glued connection of the timber-concrete structure

Abstract This paper presents results of experimental and mathematical analysis of stiffness characteristics of a composite timber-concrete structure. The composite timberconcrete structure presented herein is non-typical compared to similar types of building structures. The interaction between the timber and concrete part of the composite cross-section is not based on metal connecting elements, but it is ensured by a glued-in perforated mesh made of plywood. The paper presents results of experimental and mathematical analysis for material alternatives of the solution of the glued joint. The slip modulus values were determined experimentally. Data obtained from the experiment evaluated by means of regression analysis. Test results were also used as input data for the compilation of a 3D model of a composite structure by means of the 3D finite element model. On the basis of result evaluation, it can be stated that the stress-deformation behaviour at shear loading of this specific timber-concrete composite structure can be affected by the type of glue used. Parameters of the 3D model of both alternative of the structure represent well the behaviour of the composite structure and the model can be used for predicting design parameters of a building structure.

Verification of Mineral Particles Deposition in Wooden Construction Elements by Thermal Analysis

Wooden construction elements are exposed to many degradation factors during their use that result in structural changes. Structural changes, such as mineral particle depositions, also occur in contact with mineral solutions, which is typical for wooden elements that are partly or completely infiltrated by mine water. In this article, a mine timbering obtained from historical mining galleries in the area of Zlaté Hory is examined to verify specimen authenticity based on mineralization quantification by thermal analysis.

Application of Thermal Analysis for the Quantification of Mineralization in Surface Wooden Layers

Natural and artificial wooden mineralization leads to mineral particles deposition which positively affects certain properties. An evaluation of mineral content is therefore important. This study is focused on the application of thermal analysis for quantification of mineral content in surface wooden layers. Suitability of methodology used for specimen preparation and testing, and also derived relationships are confirmed by the example of artificial mineralized wood by organosilane.

Bonded Joints in Water-Repellent Timber Structures

Water in liquid and gaseous form is the main factor which significantly affects degradation processes in the wood. The mechanism and rate of wooden degradation processes can be effectively influenced by appropriate methods and technologies for its protection. However new knowledge, based on the possibilities of application of modern physical and chemical analytical methods, confirms that most well-known and previously commonly used protective equipment damages wooden structure. Many chemical substances, which are included in preservatives such as organic and inorganic biocides, or also flame retardants, are declared to be environmentally unacceptable. Nowadays, environmentally friendly treatment technologies of wood have increased attention to the above reasons. Wooden treatment by silicones ranks among the technologies which repellent, fire resistant and corrosion effectiveness is demonstrated by many authors. This article presents results of the experimental study that deals with the mechanical properties of bonded joints in the wood treated by silicones.

The Existing Timber Structures – Possibilities and Limits of Diagnostic Methods in Assessment Process

The wood is traditionally been applied as the building material in building and bridge construction. The number of applications of wood in building structures increases in recent years. According with this trend, the emphasis is on the development of diagnostic and monitoring methods for existing wood structures. In the paper, published results of a survey of existing wood structures in relation to the evaluation of qualitative and quantitative characteristics of the investigated structures. There are finally discussed the possibility to reproduce the results of non-destructive measurement relative to evaluate the strength characteristics of wood.

Utilization of Wood Modification for the Purpose of Moisture Volume Changes Reduction

Application of timber structures in civil engineering is completely traditional technology. On the other hand, the materials with better durability characteristics are preferred in present construction. Increased or fluctuating moisture of wood is a significant limiting factor of its life. Wood modification, which results in water intake reduction and also serves to maintain the low equilibrium moisture, may significantly improve the properties of wood, reduces the caused volumetric changes and extends its durability. Utilization of partial or total wood mineralization is just one of the material modification possibilities. This method seems to be promising due to so far gathered results, namely the anti swelling efficiency was greater than 65% for tested wooden species.

Modeling of Historical Timber Roof Truss of Želiv Monastery

Historical timber roof trusses are illustration of carpentry skills of an old era. Complexity of created structures is problem even in nowadays full usage of computer aided design. Especially in area of modeling joints and interaction of structural elements are ambiguities and inaccurate interpretations. The above issue is illustrated on 300 years old timber roof truss in Želiv monastery. The structure is Queen post shape with main trusses and secondary trusses. Especially static modeling of main trusses is problematic and difficult with utilization of beam or truss elements. Complex static model shows stiffness properties of joints as well as resistance of the whole truss structure against to climate loads and loads from rehabilitation intervention like replacement of roofing.