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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
211

Klimato įtakos automobilių kelių asfalto dangos konstrukcijos stipriui tyrimai ir vertinimas / Researches and Evaluation of Climate Influence on the Structural Strength of Road Asphalt Pavement

Paliukaitė, Miglė 01 July 2010 (has links)
Analizuojama asfalto dangos konstrukcijos elgsena Lietuvos klimato sąlygomis, įvertinant temperatūros ir drėgnio, kaip vienų iš svarbiausių klimato veiksnių, įtaką kelio asfalto dangos konstrukcijos stipriui. Pateikta krintančio svorio deflektometro matavimo metodikų apžvalga kitose šalyse. Atlikta temperatūros ir drėgnio kiekvienos dienos pokyčių analizė, įvertinant jų įtaką dangos konstrukcijai. Nustatyta kelio dangos stiprio ir Eo modulio priklausomybė nuo dangos temperatūros, matuojant kelio dangos įlinkius krintančio svorio deflektometru. Kai asfalto dangos stipris matuojamas skirtingu metų laiku ar įvairiu paros metu, tai Eo modulio reikšmės turi būti redukuojamos priimtai standartinei temperatūrai. Eksperimentiniame asfalto dangų konstrukcijų ruože atliktu tyrimu patikslintas temperatūrinis redukcijos koeficientas, kuris leidžia krintančio svorio deflektometru nustatytas asfalto dangos sluoksnių Eo modulio vertes redukuoti standartinei +20 °C temperatūrai. / This final master thesis performs asphalt pavement structural behavior of the Lithuanian climate conditions, taking into account the temperature and moisture, as one of the most important climatic factors that influence the road asphalt pavement structural strength. The Falling Weight Deflectometer (FWD) measurement methods used in other countries are presented. The temperature and moisture changes in the day are analysed, evaluating their impact on pavement design. The strength of asphalt pavement layers, as well as Eo modulus values, measured using the falling weight deflectometer, strongly depend on the pavement temperature. When we use deflectometer for measuring asphalt pavement strength at different environmental conditions and in different season, the values of Eo modulus should be reduced to the assumed standard temperature. So during this research at the experimental asphalt pavement structure the temperature correction factor was revised. The use of this factor enables to adjust the Eo modulus values of asphalt pavement layers measured by the Falling Weight Deflectometer to the standard temperature of +20 °C.
212

Dangos asfaltbetonio fizinių – mechaninių ir kitų rodiklių įtakos svarbiausių Lietuvos magistralinių kelių eksploatacinėms savybėms tyrimai / Study on the influence of asphalt concrete pavement physical – mechanical and other incices on the transport – operation properties of the main Lithuanian highways

Baltrušaitis, Andrius 13 June 2005 (has links)
The main aim of this thesis paper is to determine the influence of physical and mechanical indices of asphalt concrete pavement on the operational properties of Lithuanian highway pavement as well as on the functional lifetime of road pavement. The analysis of pavement condition of Lithuanian highways is presented. The classification regarding the damage and deformation of material used for the construction of asphalt concrete pavement and of road pavement structure is provided. The causes of the afore-mentioned damages and deformations are also explained and rectification methods which can be applied to eliminate these causes are described. The operational conditions of the road pavement and its structure as well as the applicable methods are theoretically justified. In addition, the physical and mechanical indices of asphalt concrete pavement of the highway Vilnius – Kaunas - Klaipėda (A1) and of pavement roughness in accordance with IRI research data are given. The analysis of the data allowed the correlation between the two items to be determined. The research material was processed by means of the statistical software package “Statgraphics 5.1 Plius”. Standardized physical and mechanical indices of asphalt concrete pavement which affect the functional lifetime of pavement structure are presented. The conclusions and recommendations are provided.
213

Sudėtingų sankryžų funkcionavimo įvertinimas / Evaluation of functioning of complicated junctions

Žemaitis, Domas 20 June 2005 (has links)
Purpose of the thesis – evaluate flows capacity of T. Narbuto st. – Laisvės ave. junction Identify existing problems and critical streams in the junction. Propose reasoned solutions for the existing problems, using Lithuanian and foreign countries methods, examples and experience. During preparation of Master thesis were calculated: flows of the vehicles, existing signalising cycles, traffic delays and statistical research. After analysis and research the proposals for new cycles were made for the T. Narbuto st. – Laisvės ave. and for the Justiniškių st. – Laisvės ave. Durations of new cycles were calculated, stage and phrase diagrams were calculated. Changes to existing organisation of traffic movements in the junctions were proposed. During peak hours linking proposals were made and calculated. Master thesis consists of explanatory text and following drawings: Existing and calculated signalising cycles for the Justiniškių st. – Laisvės ave. junction. Existing and calculated signalising cycles for theT. Narbuto st. – Laisvės ave. junction. Calculated signalising cycles for theT. Narbuto st.. – Laisvės ave. junction Traffic flows during morning peak hour. Traffic flows durin non peak hour. Traffic flows during evening peak hour. Changes to existing traffic organisation in the junctions.
214

Iš anksto įtemptųjų gelžbetoninių elementų įtempių ir deformacijų apskaičiavimo sluoksnių modelis / Layer Model for Stress and Strain Analysis of Prestressed Concrete Members

Zamblauskaitė, Renata 11 November 2005 (has links)
Application of refined ultimate state theories and use of high strength materials have resulted in longer spans and smaller depths of reinforced and prestressed concrete structures. Consequently, the condition of the limiting deflection rather than the strength requirement often is the governing design criterion. Long-term deflections might be up to 3 to 4 times larger than the short-term deflections. Such increments are caused by complex physical effects such as concrete creep, shrinkage and cracking, bond defects, etc. Long-term concrete creep and shrinkage deformations govern prestress losses. Structural analysis can be carried out either by traditional design code methods or numerical techniques. Although design code methods ensure safe design, they have significant limitations. Different techniques are used for strength, deflection, crack width and prestress loss analyses. Besides, most of the simplified approaches do not assess such factors as concrete shrinkage, cracking or tension stiffening. Based on a large number of empirical expressions and factors, they lack physical interpretation and do not reveal the actual stress-strain state of cracked structures. On the other hand, numerical techniques are universal and can take into account each physical effect. However, inadequacies made in the prediction of each effect might lead to significant inaccuracies when integral magnitudes such as deflection are to be assessed. Consequently, the predictions by the numerical... [to full text]
215

Visuomeninių pastatų renovacijos daugiakriterinė internetinė sprendimų paramos sistema / Multiple Criteria Web-Based Decision Support System for Refurbishment of Public Buildings

Gulbinas, Andrius 20 February 2006 (has links)
The aim of the disertation is to improve the efficiency of the of the refurbishment process of the public buildings by using methods of multiple criteria analysis, the developed model for integrated analysis of the negotiations process for refurbishment of buildings and the Multiple Criteria Decision Support System for Refurbishment of Public Buildings developed on the basis of these models.
216

Visuomeninių pastatų renovacijos daugiakriterinė internetinė sprendimų paramos sistema / Multiple Criteria Web-Based Decision Support System For Refurbishment of Public Buildings

Gulbinas, Andrius 21 February 2006 (has links)
The aim of the dissertation is to improve the efficiency of the refurbishment process of public buildings by using methods of multiple criteria analysis, the developed model for integrated analysis of the lifecycle of a public building, the model for integrated analysis of the negotiations process for refurbishment of buildings and the Multiple Criteria Decision Support System for Refurbishment of Public Buildings developed on then basis of these models.
217

Statybos rangos sutarčių vertinimo sprendimų paramos sistema internete / Internet decision support system for construction contracts evaluation

Trinkūnienė, Eva 15 December 2006 (has links)
Object of the research. The research object includes a CCA and a model of a web-based decision support system developed by integrating basic knowledge in the sphere of construction management, civil law, mathematical methods and advanced computer technologies; the model system enables effective implementation of aims of various parties of a CCA. Aim and tasks of the work. The main aim of the dissertation is to develop a theoretical model of a web-based decision support system for legal regulation of CCAs, taking in to consideration principles of construction management, improvement of effectiveness of legal regulation of CCAs, employing computer technologies, theoretical assumptions related to development of e-business systems, and etc. In order to make an effective theoretical model of a web-based decision support system for legal regulation of CCAs, the following tasks are stated: • To analyse importance of e-business in improvement of effectiveness of preparation of CCAs. • To make a feasibility study of the potential of e-business principles, of factors determining effectiveness and of decision support measures in preparation of CCAs. • To analyse principles of operating decision support systems intended for construction, law and agreement preparation. • To prepare several models for evaluation of CCAs and to select the best. • To analyse the potential of application of currently used multiple criteria analysis methods in a web-based decision support system for legal... [to full text]
218

Sunkiasvorio transporto įtaka automobilių kelių asfaltbetonio dangos funkcionavimo trukmei / Impact of Heavy Weight Vehicles on Duration of Service Life of Asphalt Concrete Road Pavement

Butkevičius, Saulius 04 December 2007 (has links)
Pastaraisiais metais Lietuvoje ženkliai padidėjęs sunkiasvorio transporto eismas sąlygoja ankstyvą daugumos šalies kelių dangų suirtį, nes jau nepakanka esamo jos stiprio. Įvairios asfaltbetonio dangos pažaidos rodo, kad ardoma ne tik danga, bet ir jos konstrukcija – tai didina išlaidas kelių remontui bei priežiūrai, mažėja eismo saugumas bei komfortiškumas. Iki šiol Lietuvoje dar nėra metodikos, kurią taikant būtų galima pakankamai tiksliai įvertinti sunkiasvorio transporto poveikį kelių dangai. Šiame darbe ištirta sunkiasvorio transporto eismo ardomojo poveikio, įvertinant Lietuvos klimato sąlygas, įtaka kelių dangos asfaltbetonio sluoksnių stipriui ir funkcionavimo trukmei. Pateikta metodika sunkiasvorio transporto eismo ir apkrovų ardančio poveikio Lietuvos kelių dangai, priklausomai nuo eismo sezoniškumo, jos stiprio, asfaltbetonio sluoksnių likutinio stiprio bei kelių dangos įtempto-deformuoto būvio kitėjimo, įvertinti. Pasiūlytas kelių dangos asfaltbetonio sluoksnių likutinio stiprio ir funkcionavimo trukmės likutinio resurso modelis. Modelis įvertina apkrovos parametrus bei jos poveikio intensyvumą, automobilių srauto sudėtį, kelių dangos sluoksnių medžiagų bei jai stiprinti naudojamų medžiagų projektines savybes, kelių dangos sluoksnio medžiagos stiprio kitėjimą, atsižvelgiant į jos suirties mastą, kelių dangos darbą, esant įvairioms vietovės klimato sąlygoms, skirtingiems žemės sankasos gruntams ir vietovės hidroterminiams rėžimams, remonto darbų kainą bei ekonominį... [toliau žr. visą tekstą] / The marked increase of heavy weight vehicle traffic in Lithuania in recent years is the reason for early deterioration of majority road pavements of the country due to inadequate strength of road pavements. Various kinds of damages in asphalt concrete pavements indicate that damage is made not only to a pavement but to its construction as well, which increases costs for road repair and maintenance and reduces road safety and comfort. There is no methodology in Lithuania that would allow to evaluate the impact of heavy weight vehicles on a road pavement with adequate preciseness. This study analyses the impact of damaging effect of heavy weight vehicle traffic on the strength and duration of service life of asphalt concrete layers in a road pavement taking account of climate conditions of Lithuania. A methodology to evaluate the damaging effect of heavy weight vehicle traffic and loads on road pavements in Lithuania depending on seasonal peculiarities of traffic, its strength, remaining strength resource of asphalt concrete layers and changes in stressed or deformed state of a road pavement is presented. A model of remaining strength of asphalt concrete layers in a road pavement and remaining resource of service life was proposed. The model evaluates load parameters and intensity of its impact, composition of vehicle flow, design characteristics of materials in layers of a road pavement and materials used when strengthening it, changes in the strength of layer material in a... [to full text]
219

Grunto stipruminių ir deformacinių savybių tyrimas triašio slėgio aparate bei jų tikimybinis vertinimas / Research of soil shear strength in triaxial test and probabilistic assesment of obtained results

Dirgėlienė, Neringa 07 February 2008 (has links)
Projektuojant ir statant įvairius pramoninius ir civilinius pastatus, visada reikalingi duomenys, kurie apibūdintų gruntų, sudarančių pastatų pagrindus, fizines ir mechanines savybes. Tokia projektuotojams ir statybos specialistams būtina informacija gaunama tiriant gruntų fizines, mechanines savybes kiekvienoje statybų aikštelėje. Šių savybių rodikliai ir pagal juos apskaičiuotas pagrindo stiprumas nustatomi su tam tikromis paklaidomis. Atskleidus tų paklaidų priežastis, šalinami tyrimo prietaisų trūkumai, tobulinami tyrimo duomenų apdorojimo metodai, tiksliau nustatomi grunto stiprumo rodikliai, ekonomiškiau projektuojami pamatai. Šiuo metu grunto kerpamojo stiprumo rodikliai dažniausiai nustatomi laboratorijose triašio slėgio ir tiesioginio kirpimo aparatais. Šių savybių rodikliai nustatyti įvairių konstrukcijų prietaisais gaunami skirtingi. Įtempimų ir deformacijų būvis grunto pagrinde geriau modeliuojamas triašio slėgio aparatu nei tiesioginio kirpimo aparatu, todėl triašio slėgio aparatas šiuo metu yra plačiai naudojamas pasaulyje nustatant grunto kerpamojo stiprumo savybių rodiklius. Daroma prielaida, kad bandinys bandymo metu deformuojasi vienodai. Šis teiginys yra pagrindinė triašio bandymo idėja. Tačiau dažniausiai bandinys deformuojasi nevienodai dėl grunto bandinio viršaus ir apačios horizontalių poslinkių suvaržymo, bandinio aukščio, nepakankamo drenavimo, guminės membranos poveikio, jo savojo svorio ir kt. Baigtinių elementų metodo analizė taip pat rodo, kad... [toliau žr. visą tekstą] / Necessary information about soil properties, which is needed for designers and constructors, is obtained in each construction site while examining physical and mechanical properties of soils. Soil strength parameters and using them determined soil bearing resistance usually are defined with some errors. If we know the reasons of errors, disadvantages of testing equipment could be eliminated, methodology of data evaluation could be developed, soil parameters could be determined more precisely and foundation designed more economically. At present triaxial and direct shear tests are the most common tests for determination of soil shear strength parameters in laboratories. Different values of soil shear strength parameters are determined using laboratory equipment of various types. Triaxial test is the most widely used method for determination of soil shear strength parameters. This is one of the most reliable methods to model stress-strain state of ground. It is assumed that soil sample deforms uniformly during the triaxial test. But it is not often the case that a sample in triaxial apparatus deforms uniformly. Questions arise, what is stress-strain distribution in soil sample, when a load is transmitted in a prescribed way? What influence does a non-uniformity have on the soil strength parameters and on foundation size calculated using determined soil strength parameters? Why sandy soil strength parameters obtained from triaxial test are bigger than the one’s, obtained... [to full text]
220

Vilniaus m. automobilių stovėjimo vietų informacinės sistemos kūrimas / Development of the information system of parking lots in Vilnius city

Palevičius, Vytautas 21 July 2008 (has links)
Magistro baigiamojo darbo tikslas – sudaryti automobilių stovėjimo aikštelių ir atskirų automobilių stovėjimo vietų informacinę sistemą Vilniaus mieste. Taip pat sudaryti geoinformacinę sistemą, kurią naudojant galima parodyti automobilių aikštelių ir informacinių stendų išsidėstymą tarp atskirų rajono dalių, bei jų tipų ir automobilių aikštelių užimtumą. Magistro darbe analizuojama ir įdiegiama keturių lygmenų informacinė sistema t.y. Vilniaus miesto priemiesčiuose ties įvažiavimais, centrinėje miesto dalyje, gyvenamuosiuose rajonuose ir atskirose automobilių stovėjimo aikštelėse. Panaudojant GIS, sukurta automobilių aikštelių informacinės sistemos duomenų bazė, kuri leidžia lengviau susisteminti duomenis. / The goal of this paper is to create an informational system generalizing information on distribution of car parking in Vilnius. As well as this, to create a geoinformational system which could be used to visually demonstrate distribution of car parking information system between separate parts of Vilnius area and analysis of distribution of their types and car parking busy. In the paper the full analysis and instal car parking four level informational system of the town near entry, of the town centre, living district. Using GIS was created car parking information basis.

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