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Number of results: 13
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Abstract

Reliable estimation of geotechnical parameters is often based on reconstruction of a complete loading process of subsoil on a specimen in laboratory tests. Unfortunately laboratory equipment available in many laboratories is sometimes limited to just a triaxial apparatus
– the use of which generates diffi culties whenever a non-axisymmetric problem is analysed.

The author suggests two simple operations that may be done to improve the quality of simulation in triaxial tests. The fi rst one is based on the use of triaxial extension along the segments of the stress path p’-q-θ for which the Lode’s angle values are positive. The second one consists in a mod-ifi cation of the equivalent stress value in such a way that the current stress level in the specimen complies with results of FEM analysis.

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Authors and Affiliations

M. Kowalska
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Abstract

Glass-aluminum building facades, as well as glazed walls intended to construct internal partitions of various types with glass doors, the purpose of which is to create fire zones, must satisfy certain fire resistance requirements stated in the codes. The offer of domestic and foreign manufacturers consists of system fire resistant partitions manufactured in the EI 30 to EI 180 fire resistance classes. Fire retardant properties of such partitions are verified experimentally, and the technical approvals are issued based on the results of such tests. In this paper the results of fire tests performed on selected partitions made by the leading domestic maker of glass-aluminum systems and representative for the whole commercial offer of Aluprof S.A. are presented. Fire resistance of doors and partitions made of aluminum sections with fire protecting insulation in one or several chambers and Polflam glazing panes differing in thickness of swelling gel have been tested. In this paper a comparative analysis of the temperature increase curves obtained on the external surface of glass panes and aluminum sections forming the tested partitions has been performed. The relationships between the internal structure of aluminum sections and glazing panes and the shape of empirical curves have been indicated. A mixed tangent-secant linearization of these curves has been proposed as well as presentation of the experimental results in the non-dimensional coordinates. Such presentation form of final experimental results allows for a clear interpretation of laboratory tests with reliable documenting of nominal fire resistance requirements.
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Authors and Affiliations

Marian Gwóźdź
1
ORCID: ORCID
Michał Marcinowski
2
ORCID: ORCID
Patrycja Antonik-Popiołek
1
ORCID: ORCID

  1. University of Bielsko-Biala (ATH), Department of Civil Engineering, ul. Willowa 2, 43-309 Bielsko-Biała, Poland
  2. Aluprof S.A.„ ul. Warszawska 153, 43-300 Bielsko-Biała, Poland
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Abstract

The paper presents numerical and experimental research on glulam delamination in a double lap connection with predominant shear stresses. Laboratory tests and wide literature survey enabled to determine timber and glue joint parameters. Cohesive zone theory, generally used for epoxy matrix and fiber reinforced composites, was adopted to modelling glue layer delamination in glulam elements. Numerical models were validated with laboratory tests.

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Authors and Affiliations

B. Kawecki
J. Podgórski
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Abstract

In the paper, a new model of friction coupling in rolling friction is presented. Apart from slips related to elastic and plastic deformation in the area of actual contact of two bodies, the mechanism includes also inertia forces related to tangential deformations. Research concerning a model of coupling mechanism of variable ratio friction wheels is described. The main objective or the investigation was to prove that the force acting along the contact line of friction wheels is significantly affected by the shape of the contact area which had not been taken into account in the relations applied so far. A new model of the coupling mechanism was suggested and verified experimentally.
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Authors and Affiliations

Czesław Koziarski
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Abstract

W strap is a crucial surface support component for underground coal mine roadways. In this study, the failure characteristics of the W strap in the field are discussed, and the loading characteristics of the strap and the faceplate are numerically and experimentally analysed. Afterwards, a loading apparatus capable of reappearing the loading environment of the strap in the field is fabricated. This loading device, combined support systems consisting of a bolt, faceplate and strap is tested under different simulated strata conditions. Failure patterns of the strap are evaluated by the 3D scanning method, and proper selection of a faceplate is explored. Results indicate that a domed faceplate can achieve a favourable supporting effect on strata, and thus it is favoured compared with a square domed faceplate. In addition, rock cavity and rock integrity beneath the strap are essential factors determining the servicing life of the overall supporting system.
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Authors and Affiliations

Xiaowei Feng
1
ORCID: ORCID
Fei Xue
2
ORCID: ORCID
Xiaotian Feng
3
ORCID: ORCID
Tongyang Zhao
2
ORCID: ORCID

  1. China University of Mining and Technology, China
  2. Shaoxing University, Key Laboratory of Rock Mechanics and Geohazards of Zhejiang Province, China
  3. Xi’an University of Architecture and Technology, Politecnico di Milano, China
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Abstract

Aviation testing is intrinsically connected with rotary telemetry, which enables engineers to measure and verify parameters of high-speed aircraft engines components during laboratory testing. The main purpose of this article is to propose new design concept of smart telemetry module for temperature measurements, which could be easily adapted to various demands of high-speed rotary components tests and is more handful, functional and affordable than other solutions on the market. The result of the work is a telemetry system in form of light weight, PCB-based, wireless powered, smart transducer. Article presents state of art analysis, design and manufacturing steps, test results and conclusions.
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Authors and Affiliations

Tomasz Kabala
1
Jerzy Weremczuk
2

  1. Łukasiewicz Research Network – Institute of Aviation, Poland
  2. Faculty of Electronics and InformationTechnology, Warsaw University of Technology, Poland
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Abstract

This paper presents the results of preliminary tests for estimating the modulus of elasticity of wooden beams from firs reinforced with PBO fiber mesh. The tests were carried out in the Materials Strength Laboratory at the Kielce University of Technology in Kielce, Poland with PN-EN 408:2004. The wooden elements were subjected to a four-point bending test with the aim of estimating the elastic modulus when bending, assuming the loading velocities of the loading forces of 5 mm/min. The obtained results show a significant increase in the load-bearing capacity of beams reinforced with PBO mesh.

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Authors and Affiliations

P. Sokołowski
ORCID: ORCID
P.G. Kossakowski
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Abstract

This paper presents a design of a tracked in-pipe inspection mobile robot with an adaptive drive positioning system. The robot is intended to operate in circular and rectangular pipes and ducts, oriented horizontally and vertically. The paper covers a design process of a virtual prototype, focusing on track adaptation to work environment. A mathematical description of a kinematic model of the robot is presented. Operation of the prototype in pipes with a cross-section greater than 210 mm is described. Laboratory tests that validate the design and enable determination of energy consumption of the robot are presented.

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Authors and Affiliations

Michał Ciszewski
Michał Wacławski
Tomasz Buratowski
Mariusz Giergiel
Krzysztof Kurc

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Abstract

In the Upper Silesian Coal Basin (Poland), numerous former workings have been left unprotected after the liquidation of mines in the 19th and the beginning of the 20th century. The workings have been located at low depths. The paper presents the results of strength tests of wood samples acquired from linings in former workings, and the obtained results have been compared to the results achieved in tests of samples of wood intended to be used in a reconstruction of a historic gallery. The tests consisted in determining the bending strength of wood in compliance with the applicable Polish standard. The results showed that the wood from historic mines was characterised by high variability of bending strength – usually much lower than that of the wood intended for construction. Too low bending strength of timber may result in caving in shallow excavation and lead to sinkhole creation on the surface.
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Authors and Affiliations

Piotr Strzałkowski
1
ORCID: ORCID
Grzegorz Dyduch
1
ORCID: ORCID

  1. Silesian University, Faculty of Mining, Safety Engineering and Industrial Automation, 2 Akademicka Str., 44-100 Gliwice, Poland
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Abstract

In this article, the issue of mining impact on road pavements and subgrade is presented, taking into account the interaction between geosynthetic reinforcement and unbound aggregate layers. Underground mining extraction causes continuous and discontinuous deformations of the pavement subgrade. Structural deformations in the form of ruts are associated with the compaction of granular layers under cyclic loading induced by heavy vehicles. Horizontal tensile strains cause the loosening of the subgrade and base layers. The granular layers under cyclic loading are additionally compacted and the depth of ruts increases. Moreover, tensile strains can cause discontinuous deformations that affect the pavement in the form of cracks and crevices. Discontinuous deformations also affect the pavement in the fault zones during the impact of mining extraction. The use of geosynthetic reinforcement enables the mitigation of the adverse effects of horizontal tensile strains. Horizontal compressive strains can cause surface wrinkling and bumps. Subsidence causes significant changes in the longitudinal and transverse inclination of road surface. Both examples of the laboratory test results of the impact of subgrade horizontal strains on reinforced aggregate layers and the selected example of the impact of mining deformation on road subgrade are presented in this article. The examples show the beneficial impact of the use of geosynthetic reinforcement to stabilize unbound aggregate layers in mining areas.

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Authors and Affiliations

Magdalena Zięba
ORCID: ORCID
Piotr Kalisz
Marcin Grygierek
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Abstract

Resilient under sleeper pads (USPs) are vibration isolators used in the ballasted track structure to improve the dynamic performance of the track, reduce vibrations and protect the ballast layer. Being permanently connected with the rail supports (sleepers or turnout bearers), the pads must exhibit a proper value of the pull-off strength, which ensures that they do not separate from the supports while being transported to the construction site or during many years of exploitation. This study focuses on the experimental determination of the pull-off strength of USPs attached to full scale prestressed concrete sleepers. Three variants are tested: two pads equipped with different anchor layers attached to the sleepers in the production plant and one pad glued to the sleeper in the laboratory. Some of the tested USPs are made of recycled styrene-butadiene rubber (SBR). An important part of the work is specification of the requirements for the pull-off strength of USPs, as well as the requirements for sleepers and turnout bearers equipped with resilient pads.
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Authors and Affiliations

Cezary Kraskiewicz
1
ORCID: ORCID
Artur Zbiciak
1
ORCID: ORCID
Henryk Zobel
1
ORCID: ORCID
Anna Al Sabouni-Zawadzka
1
ORCID: ORCID

  1. Warsaw University of Technology, Faculty of Civil Engineering, Al. Armii Ludowej 16, 00-637 Warsaw
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Abstract

Under sleeper pads (USPs) are resilient elements used in the ballasted track structures to improve dynamic behaviour of the track, reduce vibration and protect the ballast against fast degradation. As the elements permanently connected to the sleepers or turnout bearers, the pads must have an appropriate level of pull-off strength, so that they do not separate from the rail support (here: sleeper) during their transportation to the construction site or during many years of operation. In this paper, results of pull-off tests performed on four selected USP samples are presented: three samples made of SBR (styrene-butadiene rubber) granulate and one made of polyurethane. Moreover, details of the pad’s attachment to the rail support are discussed, and the requirements for the USP properties are specified, focusing on the pull-off strength determined after the weather resistance test. It is shown that only two out of four considered USP samples fulfilled the requirements specified by the authors.
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Authors and Affiliations

Cezary Kraśkiewicz
1
ORCID: ORCID
Artur Zbiciak
1
ORCID: ORCID
Jarosław Medyński
1
ORCID: ORCID
Anna Al Sabouni-Zawadzka
1
ORCID: ORCID

  1. Warsaw University of Technology, Faculty of Civil Engineering, Al. Armii Ludowej 16, 00-637 Warsaw, Poland
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Abstract

This article presents a study of a wall cladding system composed of stainless steel subframe and composite, fibre-reinforced concrete cladding panels, which was been installed on a high-rise public building. The study focused on the assessment of strength, safety and durability of design through laboratory tests and numerical analyses. The laboratory tests were conducted using a threedimensional tests stand and a full-scale mock-up of the wall cladding system built at the laboratory using the actually used materials and cladding panels. The boundary conditions and the test loads corresponded to the values of actions determined during the engineering phase of the high-rise building under analysis. Noteworthy, wind actions were verified by supplementary wind tunnel testing. In addition, the stainless steel was also tested to determine the strength properties of the material actually used in construction. These test were carried out just before commencement of the curtain wall installation. The 3D model was constructed with the application of the finite element method (FEM) to obtain adequate representation of geometry, material performance and structural behaviour of the analysed wall cladding system. Particular attention was paid to determination of the parameters defining the behaviour of the cladding system sub-frame from the angle of plastic deformations of the stainless steel and the resulting failure mechanisms of the members of the structure itself. To this end, the stainless steel was subjected to appropriate performance tests to determine material properties including the values of the proportionality limit and yield strength.
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Authors and Affiliations

Maciej Cwyl
1
ORCID: ORCID
Stanisław Wierzbicki
1
ORCID: ORCID
Rafał Michalczyk
1
ORCID: ORCID

  1. Warsaw University of Technology, Faculty of Civil Engineering, Al. Armii Ludowej 16, 00-637 Warsaw, Poland

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