Antonín Lokaj

Application of Laboratory Tests Results of Dowel Joints in Cement-Splinter Boards VELOX into the Fully Probabilistic Methods (SBRA Method)

The aim of this paper is determination of selected strength characteristics of dowel joints in cement-splinter boards VELOX on the basis of destructive testing and application of these results into the fully probabilistic SBRA method (Simulation Based Reliability Assessment).

Round Timber Bolted Joints with Mechanical Reinforcement

This paper presents the results of static tests of round timber bolted joints with inserted steel plates. All round timber joints static tests in tension were carried out on pressure machine EU 100 in laboratory of the Faculty of Civil Engineering VŠB-TU Ostrava. At first, timber specimens were tested without reinforcement. Based on these results, mechanical reinforcement methods were proposed: using modified washers and boost with screws. These samples were also tested. Rate of improvement in tensile strength was established for used reinforcement method.

Carrying Capacity of Round Timber Bolted Joints with Steel Plates under Cyclic Loading

Aim of this article is in presentation of results of dynamic tests of round timber bolted connections with slotted in steel plates. Multicyclic dynamic (fatigue) tests in tension were made with round timber joints on pulsator INSTRON in laboratory of ITAM CAS Prague. Results of laboratory tests have been statistically evaluated and completed with graphical records of deformation response to loading.

Behavior of the Spruce and Birch Wood from the Fire Safety Point of View

In the presented paper is comprehensively assessed the behavior of spruce and birch wood during fire. Samples were loaded by heat flux of 20, 35 and 50 kW/m2 in apparatus according to ISO 5657. The duration of the test was up to 30 min. The behavior of the samples was evaluated on the basis of charring rate and concentrations of carbon monoxide in smoke. Charring rate was rising with increasing heat flux density and decreasing linearly with increasing density of the samples. The maximum concentration of CO in the smoke for spruce and birch wood was observed just before the end of the test, during the phase of char layer burning.

Reliance of Embedment Strength on Dowel Diameter in Joints of Cement-Splinter Boards

The aim of this paper is determination of embedment strength of cement-splinter boards in dowel dual-shear joints on the base of destructive laboratory measurements of these joints with selected diameters. Reliance of embedment strength on dowel diameter is determined.

The Bearing Capacity of One-Shear Nail Joints in Cement-Splinter Boards

The aim of this article is in description of behavior and bearing capacity of one-shear nail joints in joints of cement-splinter boards with middle solid wood element on the base of destructive laboratory testing according to valid European standards [1]. The second part of this paper describes typical damage of these joints and comparison of these results with bearing capacity of the same way arranged and loaded joints, where however instead of cement-splinter board solid wood boards were used.

Experimental and Numerical Analysis of Steel Joints in Round Wood

Abstract The paper analyses a drawn steel joint in round logs for which several types of reinforcements have been proposed. The load-carrying capacity of the reinforcements have been tested in laboratories. At the same time, numerical modelling has been performed - it has focused, in particular, on rigidity of the joints during the loading process. Physical and geometrical nonlinearities have been taken into account. The Finite Element Method and 3D computation models have been used in the numerical calculations.

Reinforced Round Timber Joints under Static and Cyclic Loading

Aim of this article is in presentation of results of static and cyclic tests of round timber bolted joints with inserted steel plates. At first, timber specimens were tested without reinforcement. Based on static tests results, mechanical reinforcement methods were proposed and tested: using modified washers and boost with screws. Rate of improvement in tensile strength was established for used reinforcement method. Static tests in tension were carried out on pressure machine EU 100 in laboratory of the Faculty of Civil Engineering VŠB-TU Ostrava. Round timber joints multi cyclical dynamic (fatigue) tests in tension were made in laboratory of ITAM AS CR Prague and in TRI Žilina.

Carrying Capacity of Round Timber Bolted Joints with Steel Plates Under Static Loading / Únosnost Svorníkových Spojů Kulatiny S Vloženými Ocelovými Plechy Při Jednorázovém Statickém Namáhání

Abstract Aim of this article is in presentation of results of static tests of round timber bolted connections with steel plates. Round timber connections tests in tension were made on pressure machine EU100 in laboratory of the Faculty of Civil Engineering VSB-TU Ostrava. Results of laboratory tests have been statistically evaluated and completed by graphical records of deformation response on loading. Abstrakt Obsahem příspěvku je prezentace výsledků statických testů svorníkových spojů dřevěné kulatiny s vloženými ocelovými styčníkovými plechy. Testy spojů vzorků kulatiny v tahu byly prováděny staticky v lisu EU100 v laboratoři FAST VŠB-TU Ostrava. Výsledky testů byly statisticky vyhodnoceny a doplněny o grafické záznamy deformační odezvy spoje na zatížení.

Comparison of behaviour of laterally loaded round and squared timber bolted joints

In the current European standards for design of timber structures, the issue of timber-to-timber joint type is addressed only to squared timber, which makes the pinpointing of the round timber bolted joints load carrying capacity near-unfeasible due to the insufficient support in the current standards. There have been made series of tests of round timber joints in different inclinations of the loading force and also the reference tests of squared timber joints to compare the behaviour of this type of joints. Mechanical behaviour of the round and the squared timber bolted joints was tested in the laboratory of the Faculty of Civil Engineering in Ostrava. This paper presents results of static tests in tension at an angle of 0°, 90° and 60° to the grain of squared and round timber bolted joints. Load carrying capacity was determined according to the applicable standards and theories of fracture mechanics. The test results of laboratory tests were then compared with the results of theoretical calculations.