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Concurrent effects of the shear-lag and warping torsion on the performance of non-rectangular RC shear walls

Tabiee Mohammad, Abdoos Hatef, Khaloo Alireza

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 2

art. no. e138, 2023

EN

This paper aimed at analytically investigating the simultaneous effects of the shear-lag and warping torsion on the performance of non-rectangular reinforced concrete (RC) shear walls. Under the concurrent action of shear and axial loadings, the induced warping deformation due to the shear-lag as well as the warping torsion has been accounted for in the elastic region. On the strength of the minimum potential energy principle, a general formulation has been derived for the stress distribution of non-rectangular RC shear walls. By introducing the appropriate geometrical assumptions, the established formulations have then been re-written for conventional T-, U-, and L-shapes RC shear walls. The veracity of the results is ascertained through a comparative study employing finite element simulations for a U-shaped wall, and good agreement has been achieved to an extent that the proposed analytical formulation is capable to, respectively, predict the axial deformation and stress distribution with an accuracy of 95 and 90%. Also, the findings for the U-shaped wall indicate that the shear-lag can significantly affect the axial stress distribution and cracking load, and neglecting the influence of this phenomenon can lead to an inaccurate and a non-conservative design. Moreover, the contribution of the shear-lag and warping torsion has separately been highlighted for the U-shaped RC wall considered in this study.

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Propagacja wiedzy o krajobrazie kulturowym jako permanentny element programu olimpiady geograficznej

Podgórski Zbigniew

Prace Komisji Krajobrazu Kulturowego

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2020

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nr 44 (2)

51-71

PL

Olimpiada Geograficzna upowszechnia wiedzę geograficzną wśród młodzieży szkolnej od 1974 r. Szczególną rolę w tym procesie odgrywają prace pisemne wykonywane przez uczniów w zawodach I stopnia. Na podstawie danych z wybranych edycji Olimpiady Geograficznej ustalono zainteresowanie zawodników problematyką krajobrazu kulturowego. Stwierdzono, że w zawodach XIX-XLVI uczniowie przygotowali ok. 17 tys. prac pisemnych, które zawierały stosowne charakterystyki. Wynik analizy zakresu merytorycznego wytycznych do wykonania prac I stopnia dowodzi, że sugerowany zakres charakterystyki krajobrazu wymagał opisania jego genezy, struktury, funkcji, czynników kształtujących, fizjonomii oraz organizacji przestrzennej. Za ważny fakt uznano umieszczanie w pracach różnorodnych zobrazowań graficznych oraz przykładów ukazujących różne aspekty wykorzystania krajobrazu zgodnie z ideą zrównoważonego rozwoju, jak i działalności sprzecznej z jej celami i zasadami. Olimpiada Geograficzna, popularyzując wiedzę geograficzną, odwołuje się do roli człowieka w historycznym procesie formowania i zagospodarowania krajobrazów.

EN

The Geography Olympiad is a contest aimed at disseminating geographical knowledge among school youth since 1974. A special role in this process is assigned to works written by students during the first-level contest. Data from selected editions of the Geography Olympiad was used in order to determine the degree of the contestants’ interest in issues related to cultural landscape. In the contests numbered XIX-XLVI the students wrote about 17 thousand works containing relevant characteristics. The result of the analysis of the contents of work instructions for the first-level contest shows that the suggested scope of a landscape characteristic required a description of its origin, structure, functions, drivers, physiognomy and spatial organization. An important fact was that, students’ papers contained various graphic images and examples illustrating different aspects of using landscape in line with the concept of sustainable development, as well as examples of activities contrary to its objectives and principles. The Geography Olympiad, promoting geographical knowledge, makes reference to the role of humans in the historical process of landscape formation and development.

3

Analytical, FEM-numerical and experimental studies of bending of a sandwich plate-strip with metal foam core

Magnucki Krzysztof, Alsdorf Dennis, Lewiński Jerzy, Kowalski Michał, Richter Alexander, Zbierski Andrzej

Pojazdy Szynowe

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2020

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Nr 3

1--10

EN

The subject of the study is a sandwich plate-strip subjected to a four-point load. An analytical model of the strip was developed, taking into account the classical zig-zag theory, namely the broken line hypothesis. Three parts of the plate-strip are distinguished: two of them are the edge parts, where bending and the shear effect is considered, the third one is the middle part subjected to pure bending. The total maximum deflection of the plate-strip and the maximum deflection of the selected middle part of the plate-strip are calculated. The FEM-numerical study is carried out similarly to the analytical approach. The experimental study was carried out on the test stand in the Institute of Rail Vehicles TABOR. The analytical, numerical and experimental results are compared each with other. The sandwich panels can be used as parts of the floor or rail vehicle paneling.

4

Analityczne, numeryczne (MES) i doświadczalne badanie zginania trójwarstwowego pasma płytowego z rdzeniem z pianki metalowej

Magnucki Krzysztof, Alsdorf Dennis, Lewiński Jerzy, Kowalski Michał, Richter Alexander, Zbierski Andrzej

Pojazdy Szynowe

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2020

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Nr 3

11--19

PL

Przedmiotem badań jest trójwarstwowe pasmo płytowe poddane czteropunktowemu zginaniu. Opracowano analityczny model tego pasma, korzystając z klasycznej teorii linii łamanej nazywanej teorią Zig-Zag. W paśmie tym wyróżniono trzy przedziały: dwa brzegowe, w których występuje zginanie i ścinanie oraz jeden środkowy, w którym występuje czyste zginanie. Wyznaczono całkowite ugięcie maksymalne pasma płytowego oraz maksymalne ugięcie odcinka środkowego. Przeprowadzono obliczenia numeryczne metodą elementów skończonych (MES) dla takiego samego modelu pasma, jak wyżej wspomniany model analityczny. Próbę doświadczalną przeprowadzono na stanowisku badawczym w Instytucie Pojazdów Szynowych. Porównano wyniki badań analitycznych, numerycznych i doświadczalnych. Analizowane płyty warstwowe mogą być stosowane, m. in. jako części podłogi lub poszycia pojazdu szynowego.

5

Localized failure analysis of internally pressurized laminated ellipsoidal woven GFRP composite domes: Analytical, numerical, and experimental studies

Gohari Soheil, Sharifi Shokrollah, Burvill Colin, Mouloodi Saeed, Izadifar Mohammadreza, Thissen Peter

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 4

1235--1250

EN

This paper presented a systematic approach toward localized failure inspection of internally pressurized laminated ellipsoidal woven composite domes. The domes were made of thin glass fiber reinforced polymer (GFRP) woven composite layups [0,0,0], [0,30,0], [0,45,0], and [0,75,0]. The analytical results demonstrated that the circumferential regions near meridian w = 458 in prolate ellipsoidal domes and near meridian w = 908 in oblate ellipsoidal domes sustain the highest deformation under internal pressure. This observation was then confirmed by the numerical and experimental results. In addition, the numerical and experimental results showed localized rather than uniform failure in those regions, irrespective of changes in laminate stacking sequence. It was observed that localized failure occurs since the woven fibers configuration in some areas of woven remains in initial geometry (square shape), while the rests are deformed into the rhombic shape. In other words, by moving along the circumferential direction from the area close to u = 08 to u = 458 and u = 458 to u = 908, the shape of woven fibers gradually changes from square (strong area) to rhombic (weak area), and rhombic to square, respectively. Thus, to minimize failure pressure, the meridian region vulnerable to failure must initially be identified. Afterwards, the rhombic regions in the circumference corresponding to that meridian must be strengthened.

6

Analytical study of the reflection and transmission coefficient of the submarine interface

Zhang G., Hao C., Yao C.

Acta Geophysica

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2018

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Vol. 66, no. 4

449--460

EN

The analytical study of the reflection and transmission coefficient of the seafloor interface is essential for the characterization of the ocean bottom in marine seismic exploration. Based on the boundary conditions of the seafloor interface, the analytical expression of the reflection and transmission coefficient at the submarine interface is derived in this study by using the steady-state wave solution of the elastic wave in a homogeneous, isotropic medium. With this analytical expression, the characteristics of the reflection and transmission coefficient at the submarine interface are analysed and discussed using critical angles. The results show that the change in the reflection and transmission coefficient with the incidence angle presents a ‘‘segmented’’ characteristic, in which the critical angle is the dividing point. The amplitude value and phase angle of the coefficient at the submarine interface change dramatically at the critical angle, which is related to the P- and S-wave velocities in the seabed layer. Compared with the stiff seabed, the soft seabed has a larger P-wave critical angle and an absence of the converted S-wave critical angle, owing to the low P- and S-wave velocities in the solid seabed layer. By analysing and discussing the special changes that occur in the coefficient values at the critical angle, the reflection and transmission characteristics of the different incident angles are obtained. Synthetic models of both stiff and soft seafloors are provided in this study to verify the analytical results. Finally, we compared our synthetic results with real data from the Gulf of Mexico, which enabled the validation of our conclusions.

7

Studium analityczne warunków projektowych węzła dwupoziomowego z rondem

Kacprzak D., Sołowczuk A.

Inżynieria i Budownictwo

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2015

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R. 71, nr 5

237--240

PL

Przedstawiono studium analityczne możliwości zastosowania zalecanych promieni wyokrąglających wlot i wylot na rondo przy różnych zakresach kąta krzyżowania się obu dróg. Zaprezentowano również korzystne skutki stosowania wydłużonej wyspy środkowej ronda, co pozwala na projektowanie węzłów przy mniejszym kącie krzyżowania się dróg i zastosowanie zalecanej średnicy zewnętrznej ronda, przy jednoczesnej mniejszej powierzchni zajętości terenu.

EN

The paper presents an analytical study of possibility of using the recommended entry and exit radii for various ranges of the road crossing angle. The analysis demonstrates also how desirable it is to use an elongated roundabout central island, as it enables not only interchange design with smaller road crossing angle, but also using the recommended roundabout outer diameter while reducing the surface required for interchange construction.