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Number of results: 4
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Abstract

The paper presents a method of structural monitoring using measurement of vertical displacements realized optically by horizontally directed laser beam. A measuring device with an integrated rangefinder and inclinometer sensor was developed. Inclinometer sensor are used to correct measurement results of the rangefinder in order to eliminate errors resulting from spatial position changes of the laser beam. Such a solution was adopted as an alternative to a more complex and demanding method, which is the stabilization of the laser beam orientation. The proposed inclinometric correction method allows in a simple and clear way to eliminate a serious problem of the displacement measurement method with a perpendicularly directed laser beam, which is inevitable in practice the lack of permanent stability of the measuring device position. The developed measuring device is wireless, both in terms of power supply and communication with other elements of the monitoring system. In order to verify the correctness of measurements carried out by the developed device, on site tests were carried out in two industrial-warehouse buildings with functioning monitoring systems using other measurement methods, earlier verified. The tests confirmed compliance with the indications of the existing system at a level completely sufficient for structural monitoring system purposes. The conducted research show that the proposed method of displacements measurement with inclinometric correction of errors, provides accurate and reliable results, allowing also to obtain additional information about the behaviour of the structure in the place of installation of the measuring device.
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Authors and Affiliations

Stanisław Wierzbicki
1
ORCID: ORCID
Zbigniew Pióro
2 3
Marcin Osiniak
3

  1. Warsaw University of Technology, Faculty of Civil Engineering, Al. Armii Ludowej 16, 00-637 Warsaw, Poland
  2. Warsaw University of Technology, Faculty of Electronics and Information Technology, Nowowiejska15/19, 00-665 Warsaw (retired professor)
  3. WiSeNe Sp. z o.o., Taneczna 27, 02-829 Warsaw, Poland
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Abstract

The paper presents a method of structural monitoring with the use of angular and linear displacement measurements performed using inclinometer and laser measuring devices. The focus is mainly on the inclinometer measurement method, which is a solution free from the basic disadvantages of optical methods, such as sensitivity to any type of visibility restrictions, pollution or influence of weather conditions. Testing of this method was carried out in practical application in an wireless monitoring system, installed in a large-area industrial building. The measurement results performed using the inclinometers were compared with simultaneous measurements of linear displacements performed with the use of proven methods based on laser rangefinders. The research and analysis show that the method of measuring angular displacements using the inclinometers with MEMS sensors of appropriate quality is a very good, better than typical optical methods, solution of structural monitoring systems that allows to obtain accurate and reliable results.

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Authors and Affiliations

Stanisław Wierzbicki
ORCID: ORCID
Zbigniew Pióro
Marcin Osiniak
Edward Antoszkiewicz
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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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Abstract

The research focuses on the properties of foam glass, popular insulation material used in various industries and applications, including construction, chemistry and defence, after several years of use under varying load, thermal and humidity conditions. The material used as an insulating sub-base underneath industrial steel tank, which had failed with a threat of leakage of the stored high-temperature medium (200°C), was tested. After macroscopic and material evaluation of the foam glass samples, their compressive strength, water absorption, and behaviour under complex conditions including loading, high temperature, and moisture were examined experimentally. Absorption of water considerably affects reducing the foam glass performance. Investigations show that the foam glass generally does not reach the declared compressive strength. If this surface is additionally heated to high temperature, the foam glass undergoes destruction by chipping or crushing just at stresses several times lower than the limits for this material, and even with no applied load. The test results show that foam glass exposed to simultaneous action of water and high temperature undergoes progressive deterioration, resulting in a decrease in declared parameters and losing its usability. Therefore, effective and durable protection from water is of critical importance to ensure reliability of foam glass exposed to high temperatures.
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Authors and Affiliations

Stanisław Wierzbicki
1
ORCID: ORCID
Mirosław Siennicki
1
ORCID: ORCID
Marian A. Giżejowski
1
ORCID: ORCID

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

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