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In the paper the modern measurement methods of structural deformation using GOM optical measuring systems based on digital image processing were presented. First part of the work demonstrates the results of measurement of initial geometrical imperfections of steel structural elements using the Tritop optical 3D coordinate measuring machine. The met...
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... of "Blachy Pruszynski" Σ200x70x2 cross-section with span 3 m and grade of steel S350GD were tested. The beams were examined in a four-point bending scheme. The spacing of supports was 270 cm and the distance between two concentrated loads was 135 cm. The supports used in the experiment mapped theoretical fork support. The test stand is shown in Fig. 7. During the laboratory test, displacements and deformations of the beam were measured using the Aramis system, and strains were controlled using electrofusion strain gauges placed in the middle of the beam span in the upper, lower flange and in the web. Laboratory tests were preceded by the measurement of initial geometric ...
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Determining the geometric characteristics of even complex cross-sections of steel beams is not a major challenge nowadays. The problem arises when openings of various shapes and sizes appear at more or less regular intervals along the length of the beam. Such alternations cause the beam to have different stiffnesses along its length. It has differe...
Citations
... They were also used for displacements analyses of the tested beams in the GOM Correlate program (GOM, GmbH, Braunschweig, Germany). The method and scope of the application of the Tritop and Aramis systems are discussed in detail in [23]. Laboratory tests were carried out to determine the strength parameters of steel. ...
... The Tritop system enables the assessment of initial geometric imperfections. The measurement points also enable the generation of one reference coordinate system for two coupled devices in the Aramis system [23]. They were also used for displacements analyses of the tested beams in the GOM Correlate program (GOM, GmbH, Braunschweig, Germany). ...
... They were also used for displacements analyses of the tested beams in the GOM Correlate program (GOM, GmbH, Braunschweig, Germany). The method and scope of the application of the Tritop and Aramis systems are discussed in detail in [23]. ...
The presented research is a part of a broader study of strengthening methods closely associated with cold-formed sigma steel beams with tapes made of Carbon Fiber Reinforcement Polymer/Plastic (CFRP). The presented results are a continuation and extension of the tests described in previous work by the authors and refer to high-slenderness thin-walled steel sigma beams subjected to a significant large rotation. The main idea of this expanded study was to identify the effectiveness of CFRP tapes with respect to different locations, namely at a bottom-tensioned or upper-compressed flange. Six beams with a cross-section of an Σ140 × 70 × 2.5 profile by “Blachy Pruszyński” and made of S350GD steel with a span of L = 270 cm were tested in the four-point bending scheme. Two beams, taken as reference, were tested without reinforcement. The remaining beams were reinforced with the use of a 50-mm wide and 1.2-mm thick Sika CarboDur S512 CFRP tape, with two beams reinforced by placing the tape on the upper flange and two with tape located on the bottom flange. The CFRP tape was bonded directly to the beams (by SikaDur®-30 adhesive). Laboratory tests were aimed at determining the impact of the use of composite tapes on the limitation of displacements and deformations of thin-walled structures. In order to perform a precise measurement of displacement, which is, in the case of beams subjected to large rotations, a very difficult issue in itself, the Tritop system and two coupled lenses of the Aramis system were used. Electrofusion strain gauges were used to measure the deformation. In the next step, numerical models of the analyzed beams were developed in the Abaqus program. Good compliance of the results of laboratory tests and numerical analyses was achieved. The obtained results confirm the beneficial effect of the use of tapes (CFRP) on the reduction in displacements and deformations of steel cold-formed elements.
... In this article, the presented study describes one of the stages of the research program concerning the reinforcement of sigma beams with CFRP tapes subjected to four-point bending. The preparation of the beams and the description of the measuring systems used in laboratory tests are discussed in [18]. ...
... This adhesive was characterised by minimum compressive strength of 75 MPa after 7 days, a modulus of elasticity under compression of 9600 MPa, a minimum tensile strength after 7 days of 26 MPa, a deboning strength The first step of the samples' preparation consists of degreasing and matting with sandpaper and cleaning the places where CFRP tapes were foreseen to be bonded. Detailed description of the preparation of samples for testing is provided in [18]. ...
... Such points were detected at the support region (Figure 3a), where the hot-rolled C profile was used, and at the point of application The first step of the samples' preparation consists of degreasing and matting with sandpaper and cleaning the places where CFRP tapes were foreseen to be bonded. Detailed description of the preparation of samples for testing is provided in [18]. ...
In this paper, the retrofitting method of thin-walled, cold-formed sigma beams using bonded carbon fibre reinforced polymer (CFRP) tapes is proposed. The effectiveness of the presented strengthening method is investigated by the means of laboratory tests and numerical analysis conducted on simply supported, single-span beams made of 200 × 70 × 2 profile by “Blachy Pruszyński” subjected to a four-point bending scheme. Special attention is paid to the evaluation of possibility to increase the load capacity with simultaneous limitation of beams displacements by appropriate location of CFRP tapes. For this purpose, three beams were reinforced with CFRP tape placed on the inner surface of the upper flange, three with CFRP tape on the inner surface of the web, three beams with reinforcement located on the inner surface of the bottom flange, and two beams were tested as reference beams without reinforcement. CFRP tape with a width of 50 mm and a thickness of 1.2 mm was used as the reinforcement and was bonded to the beams by SikaDur®-30 adhesive. Precise strain measurement was made using electrofusion strain gauges, and displacement measurement was performed using two Aramis coupled devices in combination with the Tritop machine. Numerical models of the considered beams were developed in the Finite Element Method (FEM) program Abaqus®. Experimental and numerical analysis made it possible to obtain a very high agreement of results. Based on the conducted research, it was proved how important is the impact of the applied reinforcement (CFRP tapes) in thin-walled steel structures, with respect to the classic methods of strengthening steel building structures.
In the paper the effectiveness of strengthening of thin-walled, cold-formed sigma beams using glued steel tapes is investigated. Special attention is paid to the evaluation of the possibility of increase the load capacity with simultaneous limitation of beams displacements by appropriate location of steel tapes on the sigma cross-section. The study is based on laboratory tests and numerical analysis results. The laboratory test were conducted on eight simply supported, single-span beams made of Σ200x70x2 profile by “Blachy Pruszyński”. Two beams were reinforced with steel tape placed on the inside surface of the upper flange, two with steel tape glued on the inside surface of the web, two beams with reinforcement located on the inside surface of the bottom flange, and two beams were tested as reference beams without reinforcement. Steel tape with the width of 50 mm and thickness of 1.5 mm, made of steel S235 was used as the reinforcement and was glued to the beams with SikaDur®-30 adhesive. Precise strain measurement was made using electrofusion strain gauges and displacements measurement was performed using two lenses of Aramis software with combination with the Tritop machine. Numerical models of the considered beams were developed in the program Abaqus. Work completes the comparative analysis and conclusions.
