National Repository of Grey Literature 15 records found  previous11 - 15  jump to record: Search took 0.02 seconds. 
The numerical assessment of a full-scale truss reconstructed employing a traditional all-wooden joints
Milch, J. ; Tippner, J. ; Sebera, V. ; Kunecký, Jiří ; Kloiber, Michal ; Navrátil, M.
The assessment of mechanical behaviour of all-wooden joints used in historical timber structures such as churches, castles etc. is currently paid a big attention in the Czech Republic, and Central Europe as a whole. The reasons are (a) a high number of such structures; (b) their significance to the national cultural heritage and maintenance for preserving their cultural value; and (c) missing information about global mechanical behaviour of joints and whole truss structures when loaded. Generally, valuable historical monuments need to be evaluated as regards the structure and safety of all timber elements in the structure for their future preservation [1]. The present paper shows a novel methodology for virtual assessment of mechanical behaviour used in a historically valuable gothic truss structure of St. James's Church in Brno, which is very valuable from both structural and architectural points of view. The church was constructed between1220 and 1724, the used styles including the Romanesque, the Gothic and the Neogothic. Also carpentry master Anton Ebenberger participated [2]. The aim of this paper was to describe the real loading of a joint that corresponds to the real function of a joint in the truss structure during the loading owing to new positions of replacement joints in the truss. Currently, the truss of St. James’s church shows large defects including decayed members; therefore, renovation is needed. The restoration of the truss should be carefully implemented in the structure and analyzed beforehand. Therefore, the numerical approaches based on FEM were used to evaluate the mechanical behaviour of the beam truss with a detailed 3D solid joint.
Analysis of wood behaviour in the surroundings of a pin being pushed for the diagnostics of constructional elements of buildings
Kloiber, Michal ; Tippner, J. ; Hrivnák, J. ; Vichrová, Gábina ; Valach, Jaroslav
The technical solution of this diagnostic device for in-situ and laboratory measuring of conventional strength and the module of deformation by opening clamps in a drilled hole belongs to the field of quality and material property testing, especially concerning timber. In dependence on the specific technical solution, the device can be used for an establishment of conventional strength and the module of deformation of any material by opening clamps in a drilled hole in the examined volume. It also finds application in the situations when resistance drilling cannot be used and the mechanical properties of timber need to be established through the entire section of the examined element. Its main advantages are its speed and simple operation without a need for power distribution network.
Diagnostic methods for evaluation of construction timber
Heřmánková, V. ; Kloiber, Michal ; Tippner, J. ; Anton, O.
In the present time, there is an effort in the Czech Republic to increase the share of realization of wooden structures. For this reason the necessity to pay higher attention to wood as building material, to learn how to inspect its quality before starting the building as well as of the already bulit-in wood is evident. The paper performs diagnostic methods for evaluation of construction timber being used at the workplaces of the authors. The methods are sorted according to the kind of invasiveness onto non-destructive, semi-destructive and destructive.
The effect of chemical degradation of surface layers on mechanical properties of wood
Drdácký, Miloš ; Kloiber, Michal ; Frankl, Jiří ; Bryscejn, Jan ; Tippner, J.
The aim of the research was the determination of the effect of chemical degradation on the surface layers of wooden constructional elements and their mechanical properties and also the depth which the damage reaches. The degradation of wood surface layers was caused by chemical reactions of some compounds contained within fire-prevention coatings applied repeatedly on wooden constructions of historic buildings in the past. These include e.g. ammonium sulphate and ammonium phosphate. This paper presents experimental procedures and results obtained through measuring of mechanical properties in the damaged layer of fibrillated wood and in wood without damage. The observed properties were wood compressive and tensile strength and wood hardness. The results proved a loss in cohesion and changes in mechanical properties only in a thin surface layer.
Mechanical characteristic of timber damaged by chemical anti-fire agents
Kloiber, Michal ; Frankl, Jiří ; Drdácký, Miloš ; Tippner, J. ; Kučerová, I. ; Bryscejn, Jan
The article presents the results of a research focused on determination of effect of chemical degradation of wooden construction elements on their mechanical characteristics. The damage of wood was caused by chemical reactions of basic substances of wood mass with compounds contained in anti-fire coatings. This kind of corrosion is called surface defibering of wood.

National Repository of Grey Literature : 15 records found   previous11 - 15  jump to record:
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1 Tippner, J.
1 Tippner, Jan
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