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Seismic performance evaluation of a proposed buckling-restrained brace for RC-MRFS

Ebanesar Arunraj, Cruze Daniel, Noroozinejad Farsangi Ehsan, Seenivasan Vinscent Sam Jebadurai, Mohammad Adil Dar, Abdul Rashid Dar, Gladston Hemalatha

Civil and Environmental Engineering Reports

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2019

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Vol. 29, no. 3

164--173

EN

This paper presents a novel buckling-restrained brace (BRB) where the inner core is restrained by a concrete infilled Expanded Polystyrene Sheet (EPS) instead of the conventional concrete infilled tube section, to resist inner core buckling. It serves two purposes, firstly, the EPS is a ductile material, which is favourable in terms of seismic performance and, secondly, the outer construction material has better corrosion resistance. Thus, the life of the steel core can be prolonged. In this study, 6 BRB specimens were prepared, of which 3 BRB specimens were infilled with concrete and the remaining 3 BRB specimens with concrete and EPSs, in order to study their performance under cyclic loading. Three different core heights, all with the same core thickness, were adopted. The test results indicate that the load-carrying capacity of this novel BRB is higher than the conventional BRB. Further, the length of the steel tube also affects the strength of the seismic disaster mitigation system. Lastly, a numerical study on a single bay RC frame, with and without BRB subjected to time history analysis, was conducted to check the global performance of this novel system. It was found that the structural responses had substantially decreased.

2

The World's First Road Truss Welded Bridge in the Light of NDTs

Hołowaty J., Wichtowski B.

Biuletyn Instytutu Spawalnictwa w Gliwicach

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2018

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Vol. 62, No. 6

27--33

EN

December 2018 marks the 90-th anniversary of the construction (l 928) of the world's first road truss welded bridge (put into operation in August 1929). The bridge designed by Professor Stefan Bryły is a truss bridge with the deck below the arch, having a span length of 27 metres. The article discusses the technical condition of the bridge during non-destructive acceptance tests performed in 1929 and the results of diagnostic tests performed in 1958 and 1960 by the Gdańsk University of Technology and the West Pomeranian University of Technology in Szczecin.

PL

W grudniu 2018 roku mija 90 lat od zakończenia w 1928 roku montażu konstrukcji stalowej pierwszego na świecie drogowego kratownicowego mostu spawanego, który do eksploatacji oddano w sierpniu 1929 roku. Obiekt projektu profesora Stefana Bryły ma konstrukcję kratową z jazdą dołem o rozpiętości przęsła 27 m. W artykule opisano jego stan techniczny w trakcie nieniszczących badań odbiorczych w 1929 r. oraz badań diagnostycznych przeprowadzonych w latach 1958 i 1960 przez Politechnikę Szczecińską i Gdańską.

3

Fatigue assessment procedure for old riveted road bridges

Kużawa M., Kamiński T., Bień J.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 4

1259--1274

EN

The paper proposes a comprehensive, experimentally supported fatigue evaluation procedure dedicated to old riveted road bridges. The presented fatigue assessment of old riveted structures, very often of high historical value, is performed according to general assumptions of the Eurocodes [1], [2] and the European Recommendations for Estimation of Remaining Fatigue Life of Existing Steel Structures [3]. Essential input data used for estimation of the fatigue damage accumulation in critical bridge components as well as for prediction of residual lifetime of the whole structure is based on experimental vibration tests performed under real live loads. An original approach related to the experiment-based adaptation of the standardised fatigue loads [1], [2] to the individual operating conditions of each structure is proposed and defined in details. Its practical implementation is described in a case study of a typical historical 80-year-old road bridge crossing the Vistula River in Puławy in Poland. In the previous decades, the bridge despite of its advanced age and historical value was intensively exploited by heavy vehicles. Thus, taking into account the age of the structure and intensity of the traffic crossing the bridge the remaining fatigue resistance of the bridge critical members was evaluated by means of the proposed procedure.

4

Experimental research of the loading system for an induction motor with the use of a double-fed machine

Qawaqzeh M.Z., Kalinov A., Lotous V., Zagirnyak M.

Przegląd Elektrotechniczny

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2017

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R. 93, nr 1

173--176

EN

The performed analysis of different systems for testing induction motors under load with the use of a frequency converter enables choosing the most rational variant taking into consideration the specific conditions of the production. The specific character of use of a double-fed machine in generator mode for testing induction motors with different number of ports in loading operating modes was investigated. Conducted experimental research confirms a possibility of creation of a loading mode for induction motors with different number of ports using double-fed machines with recuperation of both active and reactive power into supply mains.

PL

Przedstawiono analizę różnych systemów testowania silników indukcyjnych pod obciążeniem z wykorzystaniem przetwornika częstotliwości, który umożliwia wybranie najbardziej racjonalnego wariantu z punktu widzenia specyficznych warunków produkcyjnych. Przebadany został specyficzny charakter wykorzystania podwójnie zasilanej maszyny w modzie generatorowym do testowania silników indukcyjnych. Przeprowadzone badania eksperymentalne potwierdziły możliwość utworzenia modu obciążenia silnika indukcyjnego z różną liczbą wejść w sytuacji kiedy liczba wejść jest różna przy użyciu podwójnie zasilanych maszyn z odzyskiwaniem zarówno energii biernej jak i czynnej do zasilających jednostek.

5

Validation of numerical models of concrete box bridges based on load test results

Bień J., Kużawa M., Kamiński T.

Archives of Civil and Mechanical Engineering

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2015

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Vol. 15, no. 4

1046--1060

EN

A Results of experimental load tests are used for the validation of numerical models applied in analyses of the concrete box bridges by means of the Finite Element Method. Six different models were used in the analyses: two created of 1-dimensional finite elements in a 2- and 3-dimensional space and four hybrid models composed of 1- and 2-dimensional elements in a 3-dimensional space. Validation of the theoretical models was based on the case of a cable-stayed bridge structure (max. span length 256 m) and a continuous multi-span beam structure (max. span length 60 m). Details of the numerical models, results of static and dynamic analyses as well as the procedure and effects of static and dynamic load tests are presented, compared and discussed.

6

Changes in properties of clay surrounding cast in-situ piles

Ghataora G. S., Ling U. K., Lee L.

Studia Geotechnica et Mechanica

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2010

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Vol. 32, nr 4

3-15

EN

For piles in clay soils, the major contribution to working load capacity is from the shaft resistance, which is influenced by the types of piles used and construction methodology adopted. In the case of preformed piles, the time-related response relates to changes in pore water pressure. However, in the case of cast-in-situ concrete piles it is anticipated that changes in soil chemistry due to migration of ions from the concrete would have an effect on soil/pile interaction. A laboratory- scale test conducted to investigate change in soil chemistry with time and its impact on load carrying capacity of cast in-situ piles in Oxford clay showed that there was a short-term increase in moisture content of soil adjacent to the piles. It also showed that there was an increase in both hydroxyl and calcium ion concentration. These also affected adhesion factor, which increased with time to a limiting value.