Practical considerations regarding results from static and dynamic load testing of bridges

Bridge tests are a helpful tool for bridge assessment and evaluation. Both in the case of a static and dynamic load testing, each element of the test: the load selection and application, the creation of a numerical model to follow the progress of the test or to check the validity of the test results, the measurement process itself and the comparative analysis of experimental results and calculations could be a source of errors in the bridge final evaluation if these errors and uncertainties are not properly considered. The article presents some of the most important factors that may bring errors in the interpretation of the test results and their comparison to targeted values or values derived from a numerical model. This, at the end, may result in the adoption of decisions that are not accurate and appropriate. The selected sources of feasible errors are presented with the division into static and dynamic loading tests. The presented examples of bridge load testing show how the use of improper test methods could lead to significant errors in bridge assessment and evaluation and, consequently, to wrong decisions.Peer ReviewedPostprint (published version

Generation: The Model and Dynamics of Change (on the Basis of Works of 19th-Century Russian Authors)

В статье на материале русской литературы XIX – начала XX веков рассмотрено становление модели поколения и ее динамика. На основании анализов сделаны следующие выводы: в изображении русских писателей модель поколения образовалась не столько на возрастной основе, сколько на почве общности исторического и культурного опыта. Модель поколения трансформировалась под влиянием важных исторических событий, интересов (искусство/наука), модных идеологий. Наиболее выразительный облик у поколений сороковых и шестидесятых годов – литературных отцов и детей. Отношение к этим двум традициям и тенденция освободиться от них стали основой идентификации очередных поколений: 1880-х, 1890-х и начала XX века. Внешним проявлением поколенческих отличий стал стиль жизни.The paper presents an attempt to reconstruct a generational model and brings some reflections on the dynamics of its changes. The following conclusions have been drawn from the analysis of a selection of works: – the model of a generation was not age-related, but emerged in the consciousness of Russian writers on the basis of a shared social, cultural and historical experience; – the ways in which individuals make sense of the past and establish generational identities are manifest in their attitude towards the prevailing values and norm systems of older generations, as well as in references to the literary images – in this case particularly to those of the 1840s and 1860s generations, of ‘fathers and sons’ – through acceptance or rejection thereof; – members of the post-1880s generation rejected the legacy of their fathers, without offering anything in return, thus becoming a generation at the crossroads. The turn-of-the-century generation was characterized by an ambivalent attitude towards their predecessors: – the generational model evolved under the impact of historical events, fashionable ideologies and fascinations for art or science, which offered a common generational experience; – the style of life came to be the outward manifestation of generational differences

Restriction mapping and infectivity of cloned geminivirus DNA

Includes bibliographical references.The bipartite ‘geminivirus -Squash Leaf Curl Virus (SLCV) has been the subject of several recent studies. Occuring in several strains, the strain known as SLCV-C is the object of this study. Since the virus is familiar to the discipline of plant virology but has not been largely considered in an experimental capacity when present in this isolate, this study endeavored to determine to which of the previously-studied strains SLCV-C appears most similar. Major aspects of the study were concerned with the determination of the physical nature of the strain, including the construction of a restriction endonuclease map and a test of the spectrum of the species to which SLCV-C proves infectious. Plasmids containing the cloned DNA of SLCV-C were isolated and purified from long-term storage, and cleaved with eighteen available restriction endonucleases such that an accurate restriction map could be produced. After a dimeric clone of the virus was produced to facilitate infection of plant tissues by rolling-circle replication, infectivity assays were performed. The results of the restriction map and infectivity assays with subsequent southern analysis show that SLCV-C possesses similar restriction sites and infects tissues in a capacity and range most similar to SLCV-R, a narrow-host-range strain characterized in previous studies.B.S. (Bachelor of Science

Podziemna Solidarność w propagandzie stanu wojennego

Praca wyłoniona w wyniku konkursu ECS/OBH na najlepszą pracę magisterską dotyczącą tematyki związanej z historią Solidarności i opozycji demokratycznej w Polsce w latach 1970–1990. Książka zarysowuje obraz podziemnej Solidarności w propagandzie stanu wojennego. Przedstawiono w niej, jak rządzący dyskredytowali działaczy związku w oczach społeczeństwa […]. Warto bliżej przyjrzeć się kreowanemu wówczas przez aparat propagandy obrazowi wroga. Sposób jego opisywania z jednej strony może powiedzieć o polityce twórców stanu wojennego, z drugiej pokazać, w jakiej atmosferze działać przyszło ludziom tworzącym solidarnościowe podziemie.Magdalena Jedlick

„Chwilami nadmiernie sophisticated”. Roman Zimand i Zniewolony umysł

W artykule przeanalizowany został szkic Romana Zimanda poświęcony Zniewolonemu umysłowi Czesława Miłosza. Główną część artykułu stanowi próba odczytania go w kontekście doświadczeń biograficznych autora. W artykule przedstawione zostało tło jego wygłoszenia oraz polemika podjęta przez Andrzeja Walickiego.The article analyzes Roman Zimand’s sketch on Czesław Miłosz’s The Captive Mind. The former mainly focuses on the latter’s biographical experience. The article presents the background of the sketch’s public reading and the polemic undertaken by Andrzej Walicki

Badanie skutków oddziaływań bocznych na wiadukcie kolejowym leżącym na łuku

In the report some investigations of bridge structure, connected with the adaptation of the railway line to speeds up to 200 km/h for conventional trains and up to 250 km/h for tilting trains were presented. A railway track is the characteristic feature of tested viaduct, because the truck is curved over the whole length of span with radius of R = 2600 m. The tests of the viaduct required the verification of influence of the dynamic effects on the ultimate limit states which corresponded to the safety of structure, as well as the serviceability limit states, related to the safety of driving and the travellers’ comfort. In frames of investigations, a special train comprised of two locomotives and four passenger cars, was used with speeds in the range between 10 and 200 km/h. The report focuses on the problems addressing the influence of horizontal actions in the case of bridge with curved truck. The measurements of the horizontal and vertical displacements as well as the accelerations of span, and the speed of crossing test train were executed. The measured and theoretically calculated chosen courses of displacements and accelerations were introduced. The degree of divergence between measured and calculated values was analysed.W referacie przedstawiono badania konstrukcji mostowej związane z dostosowywaniem linii kolejowej do dużych prędkości: vmax ≤ 200 km/h dla taboru konwencjonalnego i vmax ≤ 250 km/h dla taboru z wychylnym pudłem. Charakterystyczną cechą badanego obiektu jest tor kolejowy leżący na łuku o promieniu R = 2 600 m. Zbadanie obiektów wymagało sprawdzenia wpływu efektów dynamicznych na stany graniczne nośności – bezpieczeństwo konstrukcji oraz stany użytkowności związane z bezpieczeństwem jazdy i komfortem podróżnych. W ramach badań wykonano jazdy taborem próbnym (dwie lokomotywy i cztery wagony pasażerskie) z prędkościami dochodzącymi do 200 km/h. W referacie skoncentrowano się na zagadnieniach związanych ze skutkami odziaływań bocznych, wywoływanych przez tabor kolejowy, wynikających z położenia obiektu na łuku. Prowadzono pomiary pionowych i poziomych przemieszczeń oraz przyspieszeń przęsła i prędkości przejeżdżającego taboru. Przedstawiono wybrane zmierzone i obliczone teoretycznie przebiegi przemieszczeń i przyspieszeń. Przeanalizowano stopień rozbieżności zmierzonych i obliczonych wartości przemieszczeń i przyspieszeń wynikający z występowania sił odśrodkowych

Intake of folic acid by Polish women with higher education — a survey research: can we do more?

Objectives: The objective of the study is to determine efficacy of the Primary Prevention Program of Neural Tube Defects in Polish women with higher education in 5-year interval. Material and methods: Survey research was conducted twice (in 2008 and 2013) in 630 female students of universities: 305 female medical students and 325 female non-medical students. The survey was also done among women aged 27– 35 who graduated from medical or non-medical universities and have at least one child. Questions concerned knowledge about prophylaxis and periconceptional folic acid intake. Chi square test was used to assess the significance. Results: Knowledge concerning prophylaxis was significantly higher in female medical students comparing to non-medical ones, both in 2008 (p < 0,001), and in 2013 (p < 0,001). 92.9% in 2008 and 93.9% in 2013 of medical students knew about the necessity of periconceptional folic acid intake. Awareness of female non-medical students was lower (2008 — 35.3% and 2013 — 41.1%) and did not change in the 5-year long period (p = 0.3). There was no significant difference in preconceptional folic acid intake among mothers with medical and non-medical education (53.3% vs. 45% p = 0.4). However, the highest folic acid intake was among mothers –medical doctors who treat children with neural tube defect. Conclusions: Difference between medical and non-medical students shows that better educational programs may improve knowledge about prophylaxis. Aside from knowledge, compliance with recommendations of Primary Prevention Program of Neural Tube Defects is unsatisfactory

Virtual vibration measurement using KLT motion tracking algorithm

This paper presents a practical framework and its applications of motion tracking algorithms applied to structural dynamics. Tracking points (“features”) across multiple images is a fundamental operation in many computer vision applications. The aim of this work is to show the capability of computer vision (CV) for estimating the dynamic characteristics of two mechanical systems using a non contact, marker less and simultaneous Single Input Multiple Output (SIMO) analysis. KLT (Kanade-Lucas-Tomasi) trackers are used as virtual sensors on mechanical systems video from high speed camera. First we introduce the paradigm of virtual sensors in the field of modal analysis using video processing. To validate our method, a simple experiment is proposed: an Oberst beam test with harmonic excitation (mode 1). Then with the example of helicopter blade, Frequency Response Functions (FRFs) reconstruction is carried out by introducing several signal processing enhancements (filtering, smoothing). The CV experimental results (frequencies, mode shapes) are compared with classical modal approach and FEM model showing high correlation. The main interest of this method is that displacements are simply measured using only video at FPS (Frame Per Second) respecting the Nyquist frequency

Measuring sub-mm structural displacements using QDaedalus: a digital clip-on measuring system developed for total stations

The monitoring of rigid structures of modal frequencies greater than 5 Hz and sub-mm displacement is mainly based so far on relative quantities from accelerometers, strain gauges etc. Additionally geodetic techniques such as GPS and Robotic Total Stations (RTS) are constrained by their low accuracy (few mm) and their low sampling rates. In this study the application of QDaedalus is presented, which constitutes a measuring system developed at the Geodesy and Geodynamics Lab, ETH Zurich and consists of a small CCD camera and Total Station, for the monitoring of the oscillations of a rigid structure. In collaboration with the Institute of Structural Engineering of ETH Zurich and EMPA, the QDaedalus system was used for monitoring of the sub-mm displacement of a rigid prototype beam and the estimation of its modal frequencies up to 30 Hz. The results of the QDaedalus data analysis were compared to those of accelerometers and proved to hold sufficient accuracy and suitably supplementing the existing monitoring techniques