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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.
81

Preliminary design and multi-criteria analysis of solutions for widening an existing concrete bridge : Case of the Bridge of Chaillot in Vierzon (France)

Fline, Pierre January 2011 (has links)
Europe experienced the destruction of numerous infrastructures during World War II, followed by a reflation and a strong economic growth during the next two decades allowing a more perennial and durable situation. A classical bridge lasting in general around 80 years, one should observe that these constructions built after the war will have to be either replaced either seriously strengthened in a few years. Besides, since the needs also vary over time, transportation infrastructures built during those years might not be adapted to the actual needs anymore – some bridges might thus have to be widened. A case study has been chosen in order to simulate under which conditions the widening of such a bridge can be performed. This road bridge, located in Vierzon in France, is rather simple since it is made of simply supported prestressed concrete beams and of reinforced concrete piers. It has been chosen in particular for its reduced size – three spans of 30 m each and two road lanes – that corresponded well to this project. Based on some data provided when the bridge was initially built and on a visual inspection, this project suggests six technical solutions to double the actual amount of lanes. An evaluation of the performance of the solutions according to three criteria – durations of works, cost of the works, and environmental impact – is made in order to give recommendations regarding the optimal solution. The results show that in spite of being installed quickly, adding steel beams is more expensive and has a greater impact on the environment than adding prestressed concrete beams. Regarding the modification of piers, the solution suggesting widening the existing piers is preferable than adding new extra piers according to all the criteria. Consequently, among all the solutions analysed, the optimal one is also the simplest one. Finally, the limits of the study and some suggestions for improvements are indicated.
82

Náklady životního cyklu budovy / Building Life Cycle Costs

Bohadlová, Darina January 2012 (has links)
This diploma thesis deals with the life-cycle cost of the building for teaching and research. The theoretical part deals with the introduction of life-cycle cost method. A description ofdetermining life-cycle cost and procedure of processing. In the practical part of the budgetis prepared surveyed the building, which is divided into functional parts and the fixed costs of repair and reconstruction over the lifetime of the building. At the end of life are roughlydetermined the cost of demolition and waste removal. This whole process is summarized in the table, which sets the cost of operating the building throughout its life.
83

Strengths and limitations of bioretention sorbent amendments to simultaneously remove metals, PAHs, and nutrients from urban stormwater runoff

Esfandiar, Narges, 0000-0002-1528-7943 January 2022 (has links)
Bioretention is increasingly being employed as a stormwater management tool in urban areas, with the intent of using infiltration to address both water quantity and quality concerns. However, bioretention soil media (BSM) has limited removal capacity for dissolved contaminants; hence, amendments may be justified to improve performance. In this study, the potential of five low-cost sorbents as BSM amendments – waste tire crumb rubber (WTCR), coconut coir fiber (CCF), blast furnace slag (BFS), biochar (BC) and iron coated biochar (FeBC) – were investigated for removing several classes of contaminants from simulated stormwater (SSW). The contaminated SSW contained a mixture of metals (Cr, Cd, Cu, Pb, Ni and Zn), nutrients (ammonium, nitrate, and phosphate) and PAHs (pyrene (PYR), phenanthrene (PHE), acenaphthylene (ACY) and naphthalene (NAP)). First, batch studies were used to investigate the sorption capacities, kinetics, and the effects of different water quality parameters on sorbents performance. Then, a long-term vegetated column study was conducted to investigate the performance of three amendments (CCF, WTCR, and BFS) under intermittent runoff condition considering different runoff intensities and antecedent dry periods (ADP). The long-term effects of amendments on plant health and infiltration rate of all media were also investigated. Finally, HYDRUS-1D and a cost model were used to investigate longevity and cost-effectiveness of all BSM. Batch test results revealed that among all sorbents, BC and FeBC were only effective for removing PAHs; CFF had high sorption capacity for both metals and PAHs; BFS was very effective for metals; and WTCR was effective for some of metals and PAHs. Metal removal by BFS occurred primarily via precipitation was due to the BFS mineral structure and high/alkaline pH. The effectiveness of CCF for removing both metals and PAHs was due to its lignocellulose structure and diverse functional groups. CCF could remove metals through several mechanisms including cation exchange, complexation, and electrostatic attraction, and remove PAHs through hydrophobic interaction. Biochar in this study had a highly aromatic structure with less O-containing functional groups, and PAHs were sorbed through hydrophobic pi-pi interactions. The selectivity orders of sorbents for the removal of different metals and PAHs were Cr~Cu~Pb > Ni > Cd > Zn and PYR > PHE > ACY > NAP. This selectivity was mainly caused by differences in properties of metal ions (e.g., ionic radius, hydrogen energy, etc.) and PAHs (e.g., hydrophobicity). Phosphate was removed by BFS due to its Al, Fe and Ca contents, but the other sorbents were ineffective for nutrient removal. Metals sorption capacity of sorbents was greater at higher pH, lower salinity and lower DOC; however, PAHs sorption capacity of sorbents was generally not sensitive to water quality parameters. Column experiments showed that almost all amended and non-amended BSM were able to remove > 99% of influent metals over the 7-month experiment period (except Zn in WTCR media). Cu and Cr effluent concentrations in all media (except BFS media) increased to ~ 10% of influent concentrations during heavy rainfall which was probably due to decomposition of Cu/Cr-organic matter complexes. All bioretention columns removed > 99% of PHE and PYR (higher molecular weight PAHs) regardless of rain intensity and ADP, while the performance of different media for removing the lower molecular weight PAHs (NAP and ACY) varied with the rain intensity, and removal decreased when larger storms were experimentally simulated. For nutrients, among all media, BFS-amended media had high phosphate removal capacity (> 90%). Nitrate removal in all columns was notably affected by changes in stormwater intensity and ADP, likely due to difference in degree of saturation and the potential that anoxic conditions were created, which are favorable for denitrification. All media were ineffective in ammonium removal, and ammonium production occurred throughout experiment which might be due to the lack of nitrifiers in the media. Hydraulic properties of all media were appropriate over the entire experiment. BFS-amended media had the greatest negative effect on plant health, while CCF-amended media was supportive for plants. The transport model results showed that the predicted metal breakthrough times (according to EPA criteria) for different media were 6 years for non-amended media, 7 years for WTCR media, 25 years for CCF media, and 70 years for BFS media. Modeling PAHs, nutrients and some metals (Cr and Cu) under intermittent flow conditions are complicated and other processes and models need to be investigated as future study. Finally, cost analysis results showed that among all bioretention media, CCF- and BFS-amended media with the lowest capital and maintenance costs were the most cost-effective BSM. This research will improve our understanding of BSM amendments that will improve water quality while simultaneously support bioretention system hydrologic function as well as estimating costs of bioretention systems for a long-term application. / Civil Engineering
84

Val av ventilationssystem för kontorsverksamhet : En kostnadsjämförelse / Choice of ventilation system for office operations : A cost comparison

Johansson, Tom, Ryberg, Viktor January 2014 (has links)
Enligt Folkhälsomyndighetens uppgifter påstår 18 procent av den vuxna populationen att de lider av symtom relaterat till inomhusmiljön. Symtomen kan beröra alldagliga ohälsor däribland trötthet och huvudvärk till allvarliga åkommor såsom cancer (Folkhälsomyndigheten, 2013). Då ventilationens huvuduppgift är att tillgodose kraven på inomhusklimatet och därmed förebygga ohälsa, berör detta examensarbete problematiken kring ventilationssystemets utformning och dess ekonomiska konsekvenser. Syftet med arbetet var att identifiera vilken luftflödesprincip som är kostnadseffektivast för kontorsverksamhet utifrån två skilda typplanlösningar. Tre luftflödesprinciper har studerats, där slutligen ett CAV-, VAV- och DCV- system har utformats och dimensionerats utifrån realistiska förutsättningar och krav berörande inomhusklimatet. Ventilationssystemen utformas på skilda sätt med avseende på vilken luftflödesprincip som används, vilket bidrar till ekonomiska för- och nackdelar. Den ekonomiska undersökningen utförs genom jämförelser utifrån respektive ventilationssystems livscykelanalys, där luftflödesprinciper med likartade förutsättningar studeras i förhållande till varandra. Rapporten hanterar generella problem och tillvägagångssätt gällande problematiken kring dimensionering och utformning av ventilationssystem. De ekonomiska analyserna har resulterat i tydliga skillnader gällande investering-, drift- och underhållskostnader för respektive system. Resultatet påvisar att investeringskostnaden är den viktigaste faktorn vid val av ventilationssystem. / According to Folkhälsomyndigheten, 18 precent of the adult population claims they experience symptoms related to the indoor environment. These symptoms can consist of both common illnesses, such as fatigue and headache, to more serious diseases such as cancer (Folkhälsomyndigheten, 2013). The main task of a ventilation system is to satisfy the requirements regarding the indoor climate and thereby consequently prevent poor health. This report focuses on the complex problems regarding ventilation systems design and it´s economic consquences. The purpose with this report is to identify which airflow principle is the most cost effective for office operations basad on two distinct floor plans. Three airflow principles have been studied; consist of the CAV-, VAV- and DCV-principle. All principles were designed and dimensioned based on realistic conditions and the specific requirement regarding the indoor environment. Each ventilation system was designed differently depending on the applied airflow principle, which led to different economic pros and cons for each ventilation system. The airflow principle´s life cycle cost has been compared in an economic analysis. The economic analysises were based on comparisons between each ventilation system’s life cycle cost and it´s reigning conditions. The report deals with general problems and processes regarding the dimensioning and designing of the ventilation systems. The economic comparisons resulted in a substantial difference in investment- , operation- and the maintenance cost for each system. The results proved that the investment cost is the key factor when comparing the airflow principle´s life cycle cost.
85

Sustainable Material Solution for Flexible Pavements; Performance Evaluation and Impact Assessment of Utilizing Multiple Recycled Materials in HMA

Golestani, Behnam 01 January 2015 (has links)
The demand for pollution-free and recyclable engineering materials has been increased as the cost of energy and environmental concerns have risen. Green material design can lead to better environmental quality and sustainability of civil infrastructure. Road construction is one of the largest consumers of natural resources. Beneficial utilization of recycled materials can result in an important opportunity to save the mining and use of virgin materials, to preserve energy, and to save landfill space. Two main research questions addressed in this study are: (1) How much pollution, energy, natural resources, time and money can be salvaged by applying recycling materials to Hot-Mix Asphalt (HMA)?, (2) What are the optimum mix designs for those recycled materials in HMA?, and (3) Can multiple recycled materials be used at the same time to compensate each other*s drawbacks? This study evaluates the structural performance and environmental-economical cost and benefit by substituting one or a combination of three recycled materials in HMA. The three recycled materials are Recycled Asphalt Shingle (RAS), Municipal Solid Waste Incineration (MSWI) Bottom Ash, and Recycled Concrete Aggregate (RCA). Performance evaluation of the HMA including those recycled materials has been performed by a series of laboratory experimental tests while the environmental impact was investigated by the Life Cycle Assessment (LCA). In addition, Life Cycle Cost Analysis (LCCA) method has been employed to evaluate the benefit of the aforementioned recycled materials. In 2008, the Florida Legislature established a new statewide recycling goal of 75% to be achieved by the year 2020. The impact of this research aligns with this policy as it introduces a sustainable HMA that reduces the necessity of virgin aggregate and asphalt binder to 50% and 20%, respectively. In terms of environmental and economic impacts, in comparison with the regular HMA, it generates 25% less greenhouse gas emission, and for a period of 20 years, the cost of construction and maintenance would be 65% less.
86

Incorporating Resilience in Infrastructure Investment Decisions: Developed Framework, Specifications, Estimations, and Evaluation

Knost, Benjamin 07 December 2022 (has links)
No description available.
87

LCA and LCCA in the design of geotechnical engineering works

Samuelsson, Ida January 2023 (has links)
Geotechnical engineering works are part of almost all construction and infrastructure projects. The geotechnical engineering work contributes to the impact on the environment and gives rise to costs throughout its life cycle. Life Cycle Assessment (LCA) and Life Cycle Cost Analysis (LCCA) are established methods for evaluating a product's environmental impact and costs. However, the use of these methods is not extensive for geotechnical engineering works. A literature review showed that there is published research, but as the research topic is relatively new, there are many research gaps. A few topics in geotechnical engineering are better investigated than others and the entire life cycle is often not evaluated, usually only the production and construction stages. Although LCA and LCCA are established methods, the methodology for evaluating geotechnical engineering works needs further development to increase the evaluation work of sustainability aspects. In this licentiate thesis, a methodology is presented of how LCA and LCCA can be integrated into the geotechnical design process. The integration enables changes to the geotechnical design to further reduce the LCA and LCCA result, which is presented in the methodology. The methodology also presents a way to evaluate the possible geotechnical designs to select the most sustainable design based on the LCA and LCCA results. The thesis also presents the performance of LCA and LCCA for geotechnical engineering works and solutions to several difficulties that the geotechnical engineer may encounter during the evaluation of environmental impact and costs. / Geotekniska konstruktioner är en del av i stort sett alla konstruktions- och infrastrukturprojekt. Den geotekniska konstruktionen bidrar till påverkan på miljön samt ger upphov till kostnader under hela sin livscykel. Livscykelanalys (LCA) och livscykelkostnadsanalys (LCCA) är etablerade metoder för att utvärdera en produkts miljöpåverkan respektive kostnader. Användningen av dessa metoder är dock inte stor för geotekniska konstruktioner. En litteraturgenomgång visade att det finns publicerad forskning men då forskningsämnet är relativt nytt finns det många forskningsluckor. Ett fåtal ämnen inom geoteknik är bättre utredda än andra och hela livscykeln är oftast inte utvärderad utan vanligtvis endast produktions- och konstruktionssteget. Trots att LCA och LCCA är etablerade metoder behöver metodiken för utvärdering av geotekniska konstruktioner utvecklas för att öka utvärderingsarbetet av hållbarhetsaspekter. I denna licentiatuppsats presenteras en metodik för hur LCA och LCCA kan integreras i den geotekniska designprocessen. Integreringen möjliggör ändringar av den geotekniska designen för att ytterligare reducera LCA- och LCCA-resultatet vilket presenteras i metodiken. Metodiken redovisar även ett sätt för att utvärdera de möjliga geotekniska designerna för att utifrån LCA- och LCCA-resultaten välja den mest hållbara designen.  Uppsatsen redovisar även utförandet av LCA och LCCA för geotekniska konstruktioner och lösningar på ett flertal svårigheter som geoteknikern kan påträffa under utvärderingen av miljöpåverkan och kostnader. / <p>QC 230313</p>
88

Energy performance evaluation and economic analysis of variable refrigerant flow systems

Kim, Dongsu 09 August 2019 (has links)
This study evaluates energy performance and economic analysis of variable refrigerant flow (VRF) systems in U.S. climate locations using widelyepted whole building energy modeling software, EnergyPlus. VRF systems are known for their high energy performance and thus can improve energy efficiency in buildings. To evaluate the energy performance of a VRF system, energy simulation modeling and calibration of a VRF heat pump (HP) type system is performed using the EnergyPlus program based on measured data collected from an experimental facility at Oak Ridge National Laboratory (ORNL). In the calibration procedures, the energy simulation model is calibrated, according to the ASHRAE Guideline 14-2014, under cooling and heating seasons. After a proper calibration of the simulation model, the VRF HP system is placed in U.S. climate locations to evaluate the performance variations in different weather conditions. An office prototype building model, developed by the U.S. Department of Energy (DOE), is used with the VRF HP system in this study. This study also considers net-zero energy building (NZEB) design of VRF systems with a distributed photovoltaic (PV) system. The NZEB concept has been considered as one of the remedies to reduce electric energy usages and achieve high energy efficiency in buildings. Both the VRF HP and VRF heat recovery (HR) system types are considered in the NZEB design, and a solar PV system is utilized to enable NZEB balances in U.S. climate locations by assuming that net-metering available within the electrical grid-level. In addition, this study conducts life cycle cost analysis (LCCA) of NZEBs with VRF HP and HR systems. LCCA provides present values at a given study period, discounted payback period, and net-savings between VRF HP and HR systems in U.S. climate locations. Preliminary results indicate that the simulated VRF HP system can reasonably predict the energy performance of the actual VRF HP system and reduce between 15-45% for HVAC site energy uses when compared to a VAV system in U.S. climate locations. The VRF HR system can be used to lower building energy demand and thus achieve NZEB performance effectively in some hot and mild U.S. climate locations.
89

MECHANISTIC-BASED PERFORMANCE PREDICTION AND LIFE CYCLE COST ANALYSIS TOOLS: AN APPLICATION TO THE OHIO ROUTE 50 TEST PAVEMENT

TALLAPRAGADA, PAVAN KUMAR 13 July 2005 (has links)
No description available.
90

Förvaltning av betongbroar : Miljö- och kostnadsanalys av åtgärder på kantbalken

Ringqvist, Felix, Wollin, Erik January 2022 (has links)
Rådande beslutsfattande för broar fokuserar mestadels på de tekniska, ekonomiska och säkerhetsrelaterade perspektiven. Dessa perspektiv är viktiga men samtidigt råder det på samhällsnivå en vilja och ett krav på byggsektorn att minska sin miljöpåverkan.Detta arbete identifierar metoder, arbetssätt och strategier som leder till en ökad livslängd av betongbroar. En ökad livslängd hos vårt befintliga bestånd av betongbroar undviker stora samhällsekonomiska kostnader och är önskvärt ur ett hållbarhetsperspektiv.En miljö- och kostnadsanalys har gjorts på riskkonstruktionen kantbalken. Kantbalkens valdes för analys då konstruktionsdelen visat sig vara särskilt problematisk. Analysen jämför fyra olika förvaltningsstrategier på kantbalken på en bro vars kantbalks byts efter 40 år. Strategierna som jämförs är: byte till en kantbalk med rostfri armering, byte till en kantbalk med rostfri tvärkraftsarmering, byten till en kantbalk i standardutförande och senare installation av olika katodiska skydd. Skiljande underhållsåtgärder för dessa strategier jämförs med hänsyn till ägarkostnader och användarkostnader. Miljöpåverkan för strategierna jämförs med miljöindikatorn Global Warming Potential i produktskedet.Resultatet visar att användandet av rostfri armering i kantbalken sparar mycket på användarkostnader sett till hela livslängden på bron men med en ökad miljöpåverkan i produktskedet. Dessutom kan galvaniskt katodiskt skydd med sprutad zink vara en lovande kostnadseffektiv lösning för att förlänga livslängden på kantbalkar. / Current decision-making for bridges focuses mainly on the technical, economical and safety related perspectives. These perspectives are of course important but at the same time there exists a will on societal level and a demand on the building sector to reduce their environmental impact.This report identifies methods, ways of working and strategies that lead to an increased life-span of concrete bridges. An increased life-span of our existing stock of concrete bridges avoids large socio-economic costs and is desirable from a sustainability perspective.A life-cycle analysis and life-cycle cost assessment has been done on a construction part at risk, the edge beam. The edge beam was chosen for analysis as it was shown to be a particularly problematic part of the construction. The analysis compares four different management strategies for the edge beam of a bridge where the edge beam is replaced after 40 years. The compared strategies are: replacing the edge beam for one with stainless steel reinforcement, replacing the edge beam for one with stainless steel shear reinforcement, replacing the edge beam to a standard one and later installing different cathodic protection solutions. The differing life-cycle measures for these strategies are compared with regards to owner-costs and user-costs. Environmental impact for the strategies is compared using the environmental impact indicator Global Warming Potential in the product stage.The results show that the use of stainless reinforcement in the edge beam saves a lot on user-costs over the whole life-span of the bridge but with an increased environmental impact in the product stage. Additionally, the use of galvanic cathodic protection in the form of sprayed zinc seems to be a promising cost-effective solution to increasing the life-span of edge beams.

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