scholarly journals Geotechnical Problems Of The Foundation Of Road Embankments By The Bridge Structures

2019 ◽  
Vol 41 (4) ◽  
pp. 272-281
Author(s):  
Andrzej Batog ◽  
Elżbieta Stilger-Szydło

AbstractThis work presents the geotechnical problems occurring in the interaction area between road embankments and the bridge structures in case a subsoil characterised by complex and complicated geological and engineering conditions. These significant problems that occur during the design, performance and exploitation of the abutment structures, are illustrated on the example of engineering practice in Lower Silesia, concerning a road embankment that constitutes access to the bridge. The results of numerical analyses concerning the process of consolidation of low-strength soils and their impact on the settlements of road embankment indicate the need to carry out such analyses also in the cases, when the soft soils occur in the direct geotechnical layer under the designed embankment. The Authors included in this article a discussion regarding other effective actions and solutions that can be used in the design and performance phase, leading to the elimination or reduction of problems concerning the connection of engineering structures with road embankments, which have been recurring for years, ultimately resulting in the improvement of quality, comfort and safety of road exploitation.

Author(s):  
Amar Amavasai ◽  
Jean-Philippe Gras ◽  
Nallathamby Sivasithamparam ◽  
Minna Karstunen ◽  
Jelke Dijkstra

2000 ◽  
Author(s):  
Winfred M. Phillips

Abstract Great engineering achievements, from the Aqueducts of Rome and Hausman’s Sewer System for Paris to the Boeing 757 and the Space Shuttle, have always benefitted from international influence and content. The reliability of engineering structures and systems has always engendered the confidence of international users. U.S. citizens drive European automobiles with confidence and Europeans drive across U.S. bridges without pause. Today, international content is extensive, often formalized and regulated and a permanent part of tomorrow’s engineering. Engineers both participate in their profession worldwide and evaluate and accommodate international content at home. Multinational companies demand multinational engineering practice. “Credentials without borders” is desired. Accreditation is key to quality assurance.


2021 ◽  
Vol 15 (58) ◽  
pp. 21-32
Author(s):  
Rafael Cunha ◽  
Camila Vieira ◽  
David Amorim

Reinforced concrete structures may need repair in order to ensure the designed durability. Such necessity vary in cause and effect, but the structural diagnosis serves as the basis for adopting intervention measures. The assessment of the structural condition usually is made in loco, but sometimes numerical analyses are required as a low cost and effective preliminary diagnosis. In general, numerical analyses use hundreds or thousands of finite elements and nonlinear theories that are not often used in engineering practice. As an alternative, lumped damage mechanics (LDM) uses key concepts of classic fracture and damage mechanics in plastic hinges throughout well-known quantities such as ultimate moment and cracking moment. Such theory describes the concrete cracking by a damage variable, which can be used as a diagnosis criterion. Therefore, this paper presents LDM as a diagnosis tool to analyse actual structures. The case studies presented in this paper are a former bridge arch tested in China and a balcony that collapsed in Brazil. The results show that LDM numerical response of those structures are quite close to laboratory observations (former bridge arch) and in loco measurements (balcony).


2011 ◽  
Vol 217-218 ◽  
pp. 1758-1762
Author(s):  
Tao Chang

As the most potential member in the textile composite material, stitched textile composites have already been paid a lot attention. By the simply technology form and relatively low cost, stitched composites had attracted many domestic and foreign researchers, and were gradually used in various engineering practice. This paper using 3D micro-finite element method researches the mechanical behavior and performance of stitched composites, establishing a 3D micro-finite element model for the stitched composites under the improved locking suture way. Through analysis, it shows that each material’s stress distribution characteristics under external loading and finds that the results of this paper’s finite element data results matching well with previous studies’ results, proving the feasibility of this study, so it can be used for forecasting the mechanical properties of a variety of practical stitched composites.


2020 ◽  
Vol 10 (23) ◽  
pp. 8731
Author(s):  
Ján Erdélyi ◽  
Alojz Kopáčik ◽  
Peter Kyrinovič

Weather conditions and different operational loads often cause changes in essential parts of engineering structures, and this affects the static and dynamic behavior and reliability of these structures. Therefore, geodetic monitoring is an integral part of the diagnosis of engineering structures and provides essential information about the current state (condition) of the structure. The development of measuring instruments enables deformation analyses of engineering structures using non-conventional surveying methods. Nowadays, one of the most effective techniques for spatial data collection is terrestrial laser scanning (TLS). TLS is frequently used for data acquisition in cases where three-dimensional (3D) data with high resolution is needed. Using suitable data processing, TLS can be used for static deformation analysis of the structure being monitored. For dynamic deformation measurements (structural health monitoring) of bridge structures, ground-based radar interferometry and accelerometers are often used for vibration mode determination using spectral analysis of frequencies. This paper describes experimental deformation monitoring of structures performed using TLS and ground-based radar interferometry. The procedure of measurement, the analysis of the acquired spatial data, and the results of deformation monitoring are explained and described.


2015 ◽  
Vol 769 ◽  
pp. 252-259
Author(s):  
Jan Bencat ◽  
Maria Stehlikova ◽  
Milan Skarupa

Full–scale dynamic testing of bridge structures can provide valuable information on the service behavior and performance of structures. With the growing interest in the structural condition of highway bridges, dynamic testing can be used as a tool for assessing the integrity of bridges. From the measured dynamic response, induced by instructed passing trucks, modal parameters (natural frequencies, mode shapes and modal damping values) and system parameters (stiffness, mass and damping matrices) are obtained. These identified parameters can then be used to characterize and monitor the service of the bridge structure in the future. Analytical models of the structure can also be validated using these parameters [1,2]. The paper presents a procedure for estimating the traffic load bearing capacity of the steel arch highway viaduct Bridge Structure 205 (DC1–9, 755 m) constructed on Highway D1 in Nord Slovakia (Fig. 1) over the natural hollow basin via dynamic tests of the viaduct structures.


Author(s):  
Rohan Prabhu ◽  
Scarlett R. Miller ◽  
Timothy W. Simpson ◽  
Nicholas A. Meisel

Abstract Additive manufacturing (AM) enables engineers to improve the functionality and performance of their designs by adding complexity at little to no additional cost. However, AM processes also exhibit certain unique limitations, such as the presence of support material, which must be accounted for to ensure that designs can be manufactured feasibly and cost-effectively. Given these unique process characteristics, it is important for an AM-trained workforce to be able to incorporate both opportunistic and restrictive design for AM (DfAM) considerations into the design process. While AM/DfAM educational interventions have been discussed in the literature, limited research has investigated the effect of these interventions on students’ use of DfAM. Furthermore, limited research has explored how DfAM use affects the performance of students’ AM designs. This research explores this gap through an experimental study with 123 undergraduate students. Specifically, participants were exposed to either restrictive DfAM or dual DfAM (both opportunistic and restrictive) and then asked to participate in an AM design challenge. The students’ final designs were evaluated for (1) performance with respect the design objectives and constraints, and (2) the use of the various aspects of DfAM. The results showed that the use of certain DfAM considerations, such as minimum feature size and support material mass, successfully predicted the performance of the AM designs. Further, while the variations in DfAM education did not influence the performance of the AM designs, it did have an effect on the students’ use of certain DfAM concepts in their final designs. These results highlight the influence of DfAM education in bringing about an increase in students’ use of DfAM. Moreover, the results demonstrate the potential influence of DfAM in reducing build time and build material of the students’ AM designs, thus improving design performance and manufacturability.


Author(s):  
Damian Beben

The paper characterizes the problem of preservation of wildlife animals in connection with extension of transportation road systems. The constantly evolving transportation infrastructure in Europe, especially in its Midwestern part, on one hand connects, making it easier for people to travel and ship goods, but on the other hand it irreversibly divides and leaves a painful impress on virgin natural areas (fragmentation of the environment). The paper briefly presents the European Ecological Network Nature 2000 as the European Union program concerning the environmental protection. It enumerates possible types of animal crossings together with their characteristics. Some examples of underpasses, overpasses and crossings on the road surface are also presented. It also presents specificity and phases of designing engineering structures of this type, as well as the most common design errors and their influence over the use of such structures by animals. Finally the soil-steel bridge structures made from corrugated plates are characterized in their function as crossings for animals. The conclusion mentions complexity of the problem of animal crossing construction, which can be of use to designers and constructors of this type of engineering structures. Santrauka Straipsnyje apžvelgtos laukinės gyvūnijos išsaugojimo problemos, susijusios su besiplečiančiu transporto tinklu. Nuolat besivystanti transporto infrastruktūra Europoje, ypač Vidurio vakaruose, viena vertus, jungia ir palengvina žmonių mobilumą,sukuria jungtį su uostais, tačiau, kita vertus, daro didelę žalą natūraliai aplinkai (aplinkos fragmentacija). Straipsnyje trumpai pristatoma Europos ekologinio tinklo ,,Natura 2000“ ES programa, skirta aplinkos apsaugai. Išvardyti galimi gyvūnų perėjų tipai su jiems būdingomis charakteristikomis. Pateikiami požeminių, virš kelio ir perėjų per patį kelią pavyzdžiai. Straipsnyje taip pat apžvelgiama inžinerinių struktūrų projektavimo specifika ir fazės, aptariamos dažniausiai pasitaikančios projektavimo klaidos ir jų įtaka gyvūnams. Galiausiai apibūdinamas dirvos ir plieninių tiltų struktūros, pagamintos iš gofruotų plokštelių, naudojimas gyvūnų perėjoms. Išvadose aptariamas gyvūnų perėjų konstrukcijų problemų kompleksiškumas, į kurį turėtų atkreipti dėmesį gyvūnų perėjas konstruojantys inžinieriai ir dizaineriai. Резюме Анализируются проблемы охраны диких животных в связи с расширяющейся транспортной сетью. Постоянно развивающаяся транспортная инфраструктура в Европе, особенно на западе центральной части Европы, с одной стороны, объединяет людей, облегчает их мобильность, открывает доступ к портам, с другой – наносит непоправимый вред натуральной природе. В статье вкратце представлена программа Европейской экологической сети – Natura 2000, касающаяся охраны окружающей среды. Перечислены возможные типы переходов для животных с их типичными характеристиками. Представлены примеры подземных переходов, переходов над дорогой и по самой дороге. Проанализирована специфика и фазы проектирования инженерных структур, а также часто совершаемых ошибок при проектировании и их влияние на животных. Охарактеризовано применение для переходов животных почвенностальных структур мостов из гофрированных пластин. Проанализирована комплексность проблем, касающихся конструкций для переходов животных, на которые следует обратить внимание инженерам и дизайнерам при констру ировании переходов для животных.


Author(s):  
Jong-Sik Oh

As the second part of the author’s study, off-design behavior of the design and performance parameters in the low-solidity cascade diffuser in a centrifugal compressor is investigated. The experimental flange-to-flange compressor map serves the validity of application of the present CFD work to the detailed investigation of the low-solidity cascade diffuser. Some meanline design and performance parameters as well as three-dimensional internal secondary flow fields are studied when the flow rate is changed from deep choke to stall.


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