Wyniki wyszukiwania - BazTech

1

Elaboration of an expert system for sizing, designing and verifying flexible pavements

Bouacha Nadjet, Belachia Mouloud

Civil and Environmental Engineering Reports

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2020

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Vol. 30, no. 3

94--121

EN

The use of expert systems in the world of civil engineering, and in particular for roads, has become a necessity for the reason of the particularity, complexity, and diversity of the influencing parameters at the level of the design calculation, the latter of which represents the major source of subsequent degradation. This system consists of proposing a tool for helping the user firstly to size the body of the roadway, with several analytical methods and models (Pre-project, Boussinesq, Westgaard, and Burmister), and secondly, to offer different design possibilities (thickness and type of the material) that make up the layers. Lastly, it is to calculate the stresses and strains in order to compare them with admissible limits. The management of a knowledge base of complex natures (words, sentences, numbers, symbols, tables, calculation methods, equations, conditions, etc.) requires an adequate methodology which goes beyond the simple use of the technology but enables you to imagine the process of regrouping this mass of complex data and classifying the data, which can then be integrated into a database or spreadsheets and external programs designed with code compatible with the expert system generator. Our contribution relates initially to the formulation, organization, and preparation of the algorithms, and then the starting of the programs in order to conceive fully executable programs, the latter of which we can call the expert system. The validation of such a system was made as the work progressed, changes were made in the formulation of the rules, and the order and orientation of the data in the knowledge that the advantage of this type of system is the possibility of permanently reinforcing the database with human expertise in the field, or in books, especially so that we can avoid data loss due to illnesses, retirement, etc.

2

Performance analysis of flexible pavement with reinforced ash

Subash S. M., Mahendran N., Manoj Kumar M., Nagarajan M.

Archives of Civil Engineering

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2017

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Vol. 63, nr 3

149--162

EN

Coal ash produced from thermal power plants as a substitute for conventional construction material has increased considerably in recent years. In the past, studies on partial replacement of soil were carried out with a single type of ash. Because of the insufficient evidence, limited research has been initiated on the productive usage of Fly and Bottom Ashes. This paper aims to study the properties of these materials and investigate their efficacy in road construction. Laboratory investigations were conducted to assess chemical and physical properties and mechanical performance to evaluate both ash types in pavement construction. The rutting factor is calculated for various combinations of coal ash materials with the addition of polypropylene fiber as a reinforcement in increments of 0.1% of its total weight with an aspect ratio of 200. The analytical tool ANSYS is used to validate the service life, vertical strain and quality of reinforced ash materials.

PL

Niniejsze opracowanie zostało poświęcone zastosowaniu podczas budowy dróg materiałów wzmocnionych popiołem jako zamienników pierwotnych surowców. Badania były prowadzone przez ostatnie cztery lata w skuteczny sposób w celu uzyskania pozytywnego wyniku. Wskazówki kolegów oraz doświadczonych profesorów pomagają wypracować właściwe podejście do badań. Ponadto, studenci z PSNACET również odegrali istotną rolę w przeprowadzaniu badań laboratoryjnych. Materiały zastosowane w badaniu obejmowały: popiół denny, popiół lotny oraz włókna polipropylenowe (PPF). Popiół denny jest produktem ubocznym pozyskiwanym w przemyśle energetycznym w wyniku spalania węgla w piecu. Ma kolor czarny oraz szorstką konsystencję ze śladowymi ilościami klinkieru żwiru. Popiół lotny składa się z drobnych cząstek, które są wyjmowane z kotła wraz z gazami spalinowymi. Materiały te są bezpłatnie pozyskiwane od „Neyveli Lignite Corporation”. Włókno polipropylenowe jest polimerem termoplastycznym o wysokiej odporności na działanie substancji chemicznych, kwasów i zasad. Wykorzystywane do badań włókno o współczynniku kształtu wynoszącym 200 pozyskiwane jest z Tashi Reinforcements, Nagpur.

3

Selected aspects of design lifespan of flexible pavement with anti-fatigue course

Nagórska M., Nagórski R., Błażejowski K.

Archives of Civil Engineering

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2015

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Vol. 61, nr 1

103--118

EN

The aim of the study is to compare flexible pavement design lifespans and the main factors which create their values for a standard structure and one with an anti-fatigue course AF at different parameter values of pavement and its load, relevant to their design processes. Depending on the mixture used for the anti-fatigue course or the course thickness, durability improvement of the pavement (compared to the durability of a standard structure) can be obtained by extending the design lifespan of the asphalt base course or by extending the design lifespan of the AF course. On sections with predominantly slow traffic, the lifespan decreases significantly compared to sections with typical vehicle speed - the relative decrease is greater if anti-fatigue course is applied.

4

Finite element analysis of airfield flexible pavement

Leonardi G.

Archives of Civil Engineering

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2014

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Vol. 60, nr 3

323--334

EN

The paper presents a numerical study of an aircraft wheel impacting on a flexible landing surface. The proposed 3D model simulates the behaviour of flexible runway pavement during the landing phase. This model was implemented in a finite element code in order to investigate the impact of repeated cycles of loads on pavement response. In the model, a multi-layer pavement structure was considered. In addition, the asphalt layer (HMA) was assumed to follow a viscoelastoplastic behaviour. The results demonstrate the capability of the model in predicting the permanent deformation distribution in the asphalt layer.

5

On a certain method of selection of domain for finite element modelling of the layered elastic half-space in the static analysis of flexible pavement

Nagórska M.

Archives of Civil Engineering

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2012

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Vol. 58, nr 4

477-501

EN

In the flexible road pavement design a mechanistic model of a multilayered half-space with linear elastic or viscoelastic layers is usually used for the pavement analysis. This paper describes a domain selection for the purpose of a FE model creating of the linear elastic layered half-space and boundary conditions on borders of that domain. This FE model should guarantee that the key components of displacements, stresses and strains obtained using ABAQUS program would be in particular identical with those ones obtained by analytical method using VEROAD program. It to achieve matching results with both methods is relatively easy for stresses and strains. However, for displacements, using FEM to obtain correct results is (understandably) highly problematic due to infinity of half-space. This paper proposes an original method of overcoming these difficulties.