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1

Zachowanie okapowego węzła ramy portalowej z kształtowników giętych na zimno na podstawie pomiarów techniką DIC

Budziński Rafał, Ślęczka Lucjan

Inżynieria i Budownictwo

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2023

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R. 79, nr 9-10

452--457

PL

Węzły ram portalowych z kształtowników giętych na zimno mają inną budowę strukturalną niż węzły z kształtowników walcowanych na gorąco. Z tego powodu są zwykle klasyfikowane jako podatne i o niepełnej nośności. W artykule zwrócono uwagę na fazy pracy takich węzłów wynikające z zastosowania śrubowych połączeń zakładkowych kategorii A, przedstawiono źródła ich deformacji oraz zaprezentowano poszukiwania chwilowego środka obrotu obu składowych połączeń w węźle. Wszystkie te cechy węzłów obserwowano podczas badań doświadczalnych, a szczegółowe pomiary tych właściwości umożliwiała technika optycznej korelacji obrazu (DIC). Podczas badań wyznaczano zależności M-ϕ węzłów ram, w których schodziły się rygiel i słup wykonane ze zdwojonego kształtownika ceowego o wymiarach 450x80x4, ze stali gatunku S355.

EN

The joints of the portal frames made of cold-formed profiles have a different structural form compared to the joints made of hot-rolled rolled sections. For this reason, they are usually classified as semi-rigid and partial strength. The paper draws attention to the phases of joint behaviour resulting from the use of category A bolted lap joints, presents the sources of their deformation, and searches for the instantaneous centre of rotation of both connections in the joint. All these characteristics were observed during experimental tests and detailed measurements were made using digital image correlation (DIC) techniques. The M-ϕ response of two moment-resisting joints was investigated, where back-to-back channel sections with dimensions 450x80x4 were applied, with steel grade S355.

2

Structural performance of cold-formed steel cross-arm structure at elevated temperature

Davoudian Amir, Zeynalian Mehran, Abbasi Mehran

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 1

art. no. e66, 2023

EN

Nowadays, cross-arm truss structures made by cold-formed steel sections are used in power distribution networks. Although cold-formed steel structures have some advantages such as being lightweight and fast operation, they suffer from relatively low resistance against heat. This paper investigates the effect of elevated temperature on structural performance of cross-arm cold-formed steel structure based on experimental studies and additional numerical modeling. Furthermore, temperature-time curves of the structures were compared against thermal loading standards ISO834 and ASTM E119. For this purpose, the temperature-rotation curve of the structures and the effect of the initial vertical load before thermal loading on this curve were investigated. Also, temperature-rotation curves obtained in the laboratory as well as numerical modeling were studied and compared against each other.

3

Effect of corrosion on the buckling behaviour of cold‑formed steel channel section columns under axial compression

Nie Biao, Xu Shanhua, Chen Huapeng, Wang Youde

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 2

art. no. e70, 2023

EN

This paper presents an experimental and numerical investigation on the buckling behaviour of corroded cold-formed steel (CFS) channel section columns under axial compression. 7 stub columns and 7 medium long columns were accelerated corrosion by the outdoor periodic spray test. Prior to compression tests, the mass, residual thickness, surface morphology and initial geometric imperfection of the corroded CFS columns were measured. The failure modes, load-strain curves and load-axial displacement curves obtained from axial compression tests were discussed. Based on the corrosion morphology, the non-linear finite element (FE) model for the corroded CFS columns was then developed. Finally, the calculation method for corroded CFS channel section columns was proposed. The results indicated that with the increasing mass loss rate, the irregularity of residual thickness increased rapidly at first, and then increased slowly due to uniform corrosion. The failure mode of the corroded specimens may change from distortional buckling to local buckling as the mass loss rate increased. With the increase in mass loss rate, the buckling critical load, ultimate load, post-buckling strength and axial displacement corresponding to ultimate load decreased. The failure positions of distortional buckling and local buckling were mainly related to the corrosion degree of the flange and web, respectively. The FE results were compared against the experiment results showing a good match in terms of both the ultimate strength and failure modes.

4

Zastosowanie taśm CFRP do wzmacniania stalowych elementów profilowanych na zimno

Szewczak Ilona, Reszut Katarzyna

Przegląd Budowlany

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2020

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R. 91, nr 11

55--60

PL

W niniejszej pracy przedstawiono wybrane zagadnienia związane ze wzmacnianiem stalowych elementów profilowanych na zimno taśmami CFRP. W pierwszej części pracy dokonano przeglądu literatury i przedstawiono podstawowe informacje dotyczące stalowych elementów cienkościennych profilowanych na zimno oraz materiałów kompozytowych CFRP, podkreślając zalety i wady wykorzystania ich do wzmacniania konstrukcji stalowych. Następnie przedstawiono opublikowane, własne badania naukowe dotyczące wpływu długości zakotwienia taśm CFRP i ich lokalizacji na nośność i efektywność wzmacniania stalowych belek cienkościennych typu sigma.

EN

This paper presents selected issues related to the reinforcement of cold-formed steel elements with CFRP tapes. In the first part of the work, the literature was reviewed and basic information on cold-formed thin-walled steel elements and CFRP composite materials, emphasizing the advantages and disadvantages of using them to reinforce steel structures was presented. Moreover, published, own scientific research on the influence of effective anchorage length of the CFRP tape and their location on the load capacity and on the effectiveness of strengthening thin-walled steel beams of the sigma type with CFRP composites was presented.

5

Seismic response investigation and analytical model of light polymer material-filled CFS shear walls

Wang Wanqian, Wang Jingfeng, Guo Lei, Shen Qihan

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 2

423--436

EN

The light polymer material (LPM), prepared with suitable mix proportion and physical method, is a type of low-carbon and environmental-friendly material. Recently, the LPM is developed as structural material for cold-formed steel (CFS) structures to cover the shortages of traditional CFS shear wall. In this paper, material properties of gypsum-based and cement-based LPM including compressive strength, elastic modulus and thermal property were explored by tests. Experimental results demonstrate that LPM exhibits excellent thermal insulation, and the thermal insulation and compressive strength of LPM satisfy the demand of bearing capacity and thermal insulation property of shear walls. To explore the effect of LPM on seismic response and failure modes of CFS shear walls, three specimens are manufactured and tested under cyclic loading. The existence of LPM in CFS shear wall would restrain the failure of wall studs to some extent. Due to the restriction effect of LPM on wall studs and self-drilling screws and the bond-slip performance between LPM and studs, the shear walls exhibit better seismic behavior than traditional CFS shear walls. At last, a modified equivalent bracing model is employed to predict the lateral stiffness of LPM-filled CFS shear walls considering the effect of filling materials, rib lath, and sheathing. The lateral stiffness obtained by the proposed method is compared to the experimental results in this paper and other researches, and the proposed model is proved to supply a conservative result which is safe to be adopted in the design and application of the LPM-filled CFS shear wall.

6

Research on self-drilling screwed lap connections in steel diaphragms and the design models

Gryniewicz Marcin, Szlendak Jerzy K.

System Safety : Human - Technical Facility - Environment

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2019

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Vol. 1, nr 1

299--306

EN

In this paper, the results of a research on thin-plate single-lap connections are presented. Such type of connections is popular in steel roofs made of trapezoidal plates and other thin-walled elements. In case of a building safety it is necessary to ensure that materials with proper durability and ductility are used. Connections are one of the most important components in such structures, particularly when in-plane strength of a roof is taken into account. So far, in many existing regulations, only general calculations of such connections are conducted. However recently, discrete and computational methods can be used to build new, expanded mathematical design models, such as those presented here. Such models could be useful in an advanced design where a static analysis is combined with the safety assessment of the connections in a structural system. This is difficult when sheeting is utilized as a structural in-plane shear diaphragm. These require to take into consideration the important interactions of structure with covering and covering with another covering elements. The research is an effect of authors works on practical design approaches. Such methods can be effectively used for structural designs of buildings where the stressed skin diaphragm action is involved. Finally, practical input values about connections can be acquired from the presented data.

7

The preliminary uniaxial compression behavior of corrugated cold formed steel members

Kiliç Mahmut, Maali Mahyar, Aydin Abdulkadir Cüneyt

Architecture Civil Engineering Environment

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2019

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Vol. 12, no. 2

105--116

EN

The modern basic civil engineering concept is to design simplistic structures, by using innovative brand new manufacturing and assemblage concepts. As a result of this concept, arch type steel plates are used like the corrugated coatings. The main purpose of this work is to describe the Roll Form Machine (RFM) technology as used for the structures, especially for the roofs. Cold formed arch type steel structures may be fast and simple. These types of structures were used for temporary buildings in the US Army. Nowadays, this technology becomes popular and gets in consideration for civil life. However, the design concept of this technology does not have a theoretical model, and the calculations are evaluated according to the United States Standards. The uniaxial compressive behaviors of corrugated arch type steel members are observed, experimentally within this work.

8

Investigating the effect of the number of end-panel studs on the seismic properties of cold-formed light-steel shear-panel braces

Tafti M. R. J., Behnamfar F.

Archives of Civil Engineering

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2013

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Vol. 59, nr 2

197--214

EN

Detailed investigation of the effect of the number of end-panel studs on the seismic properties of light-steel shear-panel braces in cold-formed steel frames and in particular the associated response modification coefficients (R) factor, are presented in this paper. A total of 6 full-scale 1200×2400 mm specimens are considered, and the responses investigated under a standard cyclic loading regime. Of particular interest are the specimens’ maximum lateral load capacity and deformation behavior as well as a rational estimation of the seismic response modification factor. The study also looks at the failure modes of the system and investigates the main factors contributing to the ductile response of the tested shear-panel braces in order to suggest improvements so that braces respond plastically with a significant drift and without any risk of brittle failure, such as connection failure or stud buckling.