Дисертації з теми "Construction Engineeing"
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1
Anumba, Chinemelu Jidenka. "Construction engineering and informatics :." Thesis, Loughborough University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430239.
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Bowron, John. "Re-engineering the project procurement process through concurrent engineering." Thesis, Loughborough University, 2002. https://dspace.lboro.ac.uk/2134/6811.
Повний текст джерелаАнотація:
The construction industry in the United Kingdom is a multi-billion pound business that contributes, on average 10% of the UK Gross Domestic Product (GDP). However, it is seen by many to be underachieving in terms of service delivery and investment opportunities. Projects are frequently late and over budget much to the disappointment of those involved in the industry and especially clients. Many investigations have been commissioned and resulting reports have suggested improvements in the way the industry is organised. Procurement of construction projects in the main are undertaken using methods that support fragmentation and adversarial relationships. However, with the introduction of partnering and prime contracting some improvements have been made. Procurement of a construction project begins with the strategies developed during briefing and is only complete when the facility is handed over to the client, some contract strategies allow for the facility to be completed once it is in operation, has been maintained and eventually is demolished. Costings and programmes are then related to life-cycle issues and aspects such as maintenance have to be taken into account during the facility development stages. The adoption of Concurrent Engineering (CE) is seen to offer the construction industry a way forward. Having been adopted extensively by manufacturing in its product development stages a similar adoption by the construction industry would go some way to achieving the 30% improvement in real terms suggested by Latham [1994] and Egan [1998]. The research described in the thesis aims to develop a new procurement method for the delivery of construction projects. The approach adopted was to identify current methods of procurement and the problems associated with each method. Then using Concurrent Engineering as a basis, a new procurement model was developed that offered potential improvements in the construction process between the stages of Clients Briefing and Detailed Design. The resulting model was evaluated through the application of CE principles into the process and by the presentation and discussion of the method with a number of industry participants, followed by the completion and assessment of a questionnaire. The model was shown to fulfil the principles of CE and could be adopted into construction. It offers a new approach to procurement which in turn would save costs and time and potentially improve the quality of the final construction product.
3
Poolvoralaks, Suriyon. "Groupware system in construction engineering." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/41365.
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4
Champion, Ronan. "Acceleration in construction and engineering contracts." Thesis, King's College London (University of London), 2005. https://kclpure.kcl.ac.uk/portal/en/theses/acceleration-in-construction-and-engineering-contracts(caf6065f-f99b-40b6-aa76-73dada69ad47).html.
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5
Riley, Michael John. "Re-engineering the construction procurement process." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395375.
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Demacopoulos, Alexander Christos. "International engineering and construction business environments." Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/52894.
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Conocimiento, Dirección de Gestión del. "Journal of Construction Engineering & Management." ASCE Library, 2004. http://hdl.handle.net/10757/655334.
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Aboulezz, Mohamed A. "Mapping the construction engineering and management discipline." Link to electronic thesis, 2003. http://www.wpi.edu/Pubs/ETD/Available/etd-0210103-120659.
Повний текст джерелаАнотація:
Thesis (M.S.)--Worcester Polytechnic Institute.Keywords: Discipline mapping; Construction engineering and management; Bibliometric study; JME; Research methods. Includes bibliographical references (p.88-91).
9
Yemane, Samiel, and Hjalmar Eriksson. "Projekteringsverktyget “Value Engineering” i byggprojekt." Thesis, Tekniska Högskolan, Jönköping University, JTH, Byggnadsteknik och belysningsvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-50189.
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10
Majani, Ruby. "Gut construction : scaffolds for intestinal tissue engineering." Thesis, University of Nottingham, 2009. http://eprints.nottingham.ac.uk/29319/.
Повний текст джерелаАнотація:
Forming tissues in the laboratory to replace diseased or dysfunctional tissue or act as models for drug treatment is the goal of tissue engineering. The large intestine epithelium (colon surface) is a tissue which could benefit from both diseased and non-diseased models for the purpose of tackling colon cancer causes and treatments. Scaffolds (cell supports) are a pivotal part in many tissue engineering strategies. This thesis describes the design and production of two separate scaffolds based on the degradable polymer poly(lactic-co-glycolic acid) (PLGA). The first was a two dimensional scaffold to mimic the intestinal basement membrane which was modified with an oxygen plasma. The changes to the surface due to plasma and the degradation properties of the scaffold were extensively studied with SEM, XPS, AFM and GPC. The data showed that the oxygen plasma induced surface porosity and associated changes to surface roughness. The surface chemistry as detected by XPS was unchanged by both plasma treatment and degradation in buffered solution. The plasma treatment did lead to a dramatic loss in molecular weight but the degradation profile of both the untreated and etched films was similar. Extensive cell studies with SEM, live/dead, alamarBlue and Hoechst DNA assays showed that intestinal cells on the plasma treated scaffold was enhanced in terms of morphology, metabolic activity and proliferation. Finally, a two dimensional co-culture model using epithelial and myofibroblasts cell lines on the modified PLGA scaffold was achieved. The second scaffold was a three dimensional scaffold bearing the crypt like architecture of the colon. An accurate mould produced through electron beam lithography using dimensions measured from mouse histological sections. PLGA particles were used to fill the mould and sintered to produce the scaffold. A unique cell seeding approach using cell sheets was used. The cell sheets were produced on plasma polymers of acrylic acid and the discharge power was shown to affect surface wettability, chemistry and cell viability. The cell sheet approach proved to enhance cell attachment to the scaffold compared to individual cell seeding. Finally, a bilayer scaffold with model protein to mimic Wnt protein presence in the lower half of the crypt was studied with ToF-SIMS.
11
Naito, Seiji 1969. "Strategic alliances of engineering & construction firms." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/10102.
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Sidaross, Monique. "Ethical Decision-Making in Construction Engineering Projects." ScholarWorks, 2018. https://scholarworks.waldenu.edu/dissertations/4889.
Повний текст джерелаАнотація:
Problems exist with ethical decision-making in U.S. construction engineering projects.
The purpose of this study was to explore factors that affect ethical decision-making in engineering construction in the United States. The general concepts of marketing ethics, Kohlberg's discussion of ethical and moral reasoning development, and Gillian's discussion of ethical care served as the basis of the conceptual framework. Factors that inhibit ethical decision making were addressed in the research questions. The resulting narrative framework included implementable initiatives based on these factors that could improve the quality of ethical decision-making and the impact of these initiatives on the cost and quality of construction engineering projects. The use of qualitative grounded theory design led to findings from the research questions and enabled the development of a theory to explain the phenomenon. The research was based on data collected from interviews with a purposive sample of 12 civil engineers with 15 to 45 years of forensic and managerial experience with construction engineering projects. The constant comparative method was used to analyze the data. The principal finding from the research was that unethical decision-making in the legal and political systems undermines the image and authority of construction engineers in the United States. The findings of the study may cause social change by indicating how to enhance the ethical behavior of individuals involved in decision-making within the U.S. construction engineering industry, leading to improvements in the cost and quality of construction projects that benefit individual stakeholders as well as society.
13
Chavez, Jose O. "Notes on foundation engineering." Thesis, Kansas State University, 1985. http://hdl.handle.net/2097/9827.
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14
Edgren, Fredrik. "Physically Based Engineering Models for NCF Composites." Doctoral thesis, Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3927.
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15
Olivier, A. H. "Supporting consistency in linked specialized engineering models through bindings and updating." Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/697.
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16
Simpkins, William J. "Value engineering in government and private sector construction." Thesis, Springfield, Va. : Available from National Technical Information Service, 2000. http://handle.dtic.mil/100.2/ADA383401.
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17
Ramokolo, Bruce Sabelo Mpumelelo. "The capacity of emerging civil engineering construction contractors." Thesis, Nelson Mandela Metropolitan University, 2009. http://hdl.handle.net/10948/873.
Повний текст джерелаАнотація:
Construction management competencies are essential to realise sound practices among and to realise optimum performance by, inter alia, emerging civil engineering contractors. Such competencies enable a clear focus on the business of construction and the management of projects, with increased efficiency and reduced costs as a benefit. The objective of the MSc (Built Environment) treatise study were to determine the current practices and performance of emerging civil engineering construction contractors operating in the Nelson Mandela Bay Metropole. The descriptive method was adopted in the empirical study. The salient findings of the study are: most of the emerging civil engineering construction contracting organisations lack construction management competencies; construction resources are inappropriately managed leading to construction failures; most of the emerging civil engineering construction contracting organisations lack adequate supervision resulting to poor workmanship; there is a shortage of skilled labour amongst emerging civil engineering construction contractors; procurement processes are inappropriate leading to under capacitated emerging civil engineering construction contracting organisations being awarded contracts; most emerging civil engineering construction contracting organisations lack the requisite aptitude for construction; there is a lack of capacity at all management levels of emerging civil engineering construction organisations in managing the business of construction and that of projects; the nine functions of organisations are not comprehensively represented, and self-ratings indicate inadequacy relative to the management function of control, and relative to certain activities of the organising function. Conclusions include that emerging civil engineering construction contracting organisations need to be comprised of technical teams that possess adequate competencies and that use the construction technology to its full use enabling their organisations to stay abreast of their competitors. Recommendations that can contribute towards improving the status quo include: formal civil engineering and construction management education, resources must be present and training should be promoted throughout the industry at all levels of management to ensure proper supervision and correct use of adequately trained labour, skilled or semi-skilled, incapacitated emerging civil engineering construction contractors should be awarded contracts through appropriately and structured procurement procedures, adequate aptitude in construction should be promoted and enhanced in order to realise conceptualisation and visualisation capabilities, comply with legislation, maintain records and communicate using state of the art technology, optimally manage the finances, have the requisite resources and undertake the work efficiently, interact with the respective publics, and market the organisation to ensure sustainability thereof.
18
Willmer, Gillian. "Development of risk models for engineering construction projects." Thesis, Online version, 1988. http://ethos.bl.uk/OrderDetails.do?did=1&uin=uk.bl.ethos.327826.
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19
Jones, Barry Kenneth. "A model for collaborative engineering the construction industry." Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266868.
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20
Empie, Laurel E. "Measuring and interpreting civil engineering vibrations." Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/21430.
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21
Fung, Leung Pik-wah. "Strategic human resources management in a civil engineering/construction company /." [Hong Kong] : University of Hong Kong, 1991. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13055045.
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22
Burroughs, Gary Leslie. "The response to environmental economic drivers by civil engineering contractors in South Australia." Title page, contents and abstract only, 2000. http://web4.library.adelaide.edu.au/theses/09ENV/09envb972.pdf.
Повний текст джерелаАнотація:
Bibliography: leaves 91-93. Examines the response of two civil engineering construction contractors in South Australia to environmental economic conditions and market requirements using primarily an action research methodology whilst the researcher was engaged as the environmental manager at both corporations.
23
Garcia, Maria-José. "Engineering rubber bushing stiffness formulas including dynamic amplitude dependence." Licentiate thesis, KTH, Aeronautical and Vehicle Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4017.
Повний текст джерелаАнотація:
Engineering design models for the torsion and axial dynamic stiffness of carbon black filled rubber bushings in the frequency domain including amplitude dependence are presented. They are founded on a developed material model which is the result of applying a separable elastic, viscoelastic and friction rubber component model to the material level. Moreover, the rubber model is applied to equivalent strains of the strain states inside the torsion or axial deformed bushing previously obtained by the classical linear theory of elasticity, thus yielding equivalent shear moduli which are inserted into analytical formulas for the stiffness. Therefore, unlike other simplified approaches, this procedure includes the Fletcher-Gent effect inside the bushing due to non-homogeneous strain states. The models are implemented in Matlab®. In addition, an experimental verification is carried out on a commercially available bushing thus confirming the accuracy of these models which become a fast engineering tool to design the most suitable rubber bushing to fulfil user requirements. Finally, they can be easily employed in multi-body and finite element simulations
24
G, Hemanth Kumar. "Eexperimental and numerical studies on behaviour of frp strengthened deep beams with openings." Thesis, 2012. http://ethesis.nitrkl.ac.in/3912/1/E_thesis__Hemanth.pdf.
Повний текст джерелаАнотація:
Reinforced concrete deep beams are widely used as transfer girders in offshore structures and foundations, walls of bunkers and load bearing walls in buildings. The presence of web openings in such beams is frequently required to provide accessibility such as doors and windows or to accommodate essential services such as ventilating and air conditioning ducts. Enlargement of such openings due to architectural/mechanical requirements and/or a change in the building’s function would reduce the element’s shear capacity, thus rendering a severe safety hazard. Limited studies have been reported in the literature on the behavior and strength of RC deep beams with openings. When such enlargement is unavoidable adequate measures should be taken to strengthen the beam and counteract the strength reduction.The present experimental investigation deals with the study of deep beams containing openings and the validation of results with FEM model using ANSYS. A total of 5 deep beams with openings are casted without shear reinforcements and are tested under three-point loading. Test specimen has a cross section of 150x460 mm and a total length of 1200 mm. Two circular openings, one in each shear span, are placed symmetrically about the mid-point of the beam. The structural response of RC deep beams with openings was primarily dependent on the degree of the interruption of the natural load path. Externally bonded GFRP shear strengthening around the openings was found very effective in upgrading the shear strength of RC deep beams. The strength gain caused by the GFRP sheets was in the range of 68–125%. Finite element modeling of RC deep beams containing openings strengthened with GFRP sheets is studied using ANSYS and the results are compared with experimental findings.
25
Tudu, Chhabirani. "Study of torsional behaviour of rectangular reinforced concrete beams wrapped with GFRP." Thesis, 2012. http://ethesis.nitrkl.ac.in/3914/1/CHHABI-THESIS.pdf.
Повний текст джерелаАнотація:
Fiber Reinforced Polymer (FRP) as an external reinforcement is used extensively to deal with the strength requirements related to flexure and shear in structural systems. But the strengthening of members subjected to torsion is explored only recently. Torsion failure is an undesirable brittle form of failure which should be avoided specially in the earthquake prone areas. In the present work, the behaviour and performance of rectangular reinforced concrete beams strengthened with externally bonded Glass Fibre Reinforced Polymer (GFRP) fabrics subjected to combined flexure and torsion is studied experimentally.
Rectangular RC beams externally bonded with GFRP fabrics were tested to failure using an arrangement which transfer torque to the central part of the beam through two opposite cantilevers called moment arms. Each arm is subjected to equal static loading during the experiment. Total nine RC beams were cast and tested for the study. All the beams were designed to fail in torsion. One of the beam was used as a control beam and eight beams were strengthened using different configurations and different types of GFRP fabrics. The study is restricted to continuously wrapped GFRP fabrics.
Experimental data on ultimate & first cracking loads, angle of twist and failure modes of each of the beams were obtained. The effect of different types and configuration of GFRP on first crack load, ultimate load carrying capacity and failure mode of the beams were investigated.
The experimental results have been validated with finite element analysis by using ANSYS software and found to be in good agreement with analytical values. The experimental results show that externally bonded GFRP can increase the torsional capacity of the beam significantly. The results also indicate that the most effective configuration is the full-wrap of GFRP fabrics. In addition GFRP applied in 450 with axis of the beam gives more strength than GFRP applied in 900 with the axis of the beam.
26
Panda, Saleema. "Nonlinear Finite Element Static and Dynamic Analyses of Stiffened Plates." Thesis, 2018. http://ethesis.nitrkl.ac.in/9452/1/2018_PhD_SPanda_513CE1028_Nonlinear.pdf.
Повний текст джерелаАнотація:
In the present work, finite element method is used to study the behaviour of arbitrary shaped thin stiffened plates. The nonlinear static and dynamic analyses are carried out for both bare as well as stiffened plates. The formulation is generalised using a mapping technique so that the analysis is performed in a square domain. It uses a superparametric element in which the displacement field is defined by the shape functions of an ACM plate bending element along with in-plane displacements and geometry by cubic serendipity shape functions. The concentric and eccentric stiffeners, whether straight or curvilinear are ideally modelled so that they can be placed anywhere on the plate and not necessarily along the mesh grids as usually presented in the conventional methods. The formulation accommodates different
boundary conditions which can be applied along the curved/straight boundary of the plate and for various types of loadings. To account for the nonlinearity, von Karman’s large deflection theory is used, and the formulation is performed in the total Lagrangian coordinate system. The nonlinear equations of large deformation are solved using Newton Raphson technique whereas the nonlinear equations of large amplitude free flexural vibration are solved by direct iteration method that uses the linear mode shape as a starting vector. The time-dependent equation in the transient analysis is solved using the average acceleration
method of Newmark’s scheme. Various numerical examples of arbitrary shapes and boundary conditions are presented to show the versatility of the formulation and its efficacy
is validated with the published results. Some new results obtained by the proposed method are also presented.
27
Pramod, Chaudhari Saurabh. "A Comparative Analysis on Factors Affecting Functioning of Airports in India." Thesis, 2018. http://ethesis.nitrkl.ac.in/9486/1/2018_MT_216CE3069_CSPromod_Comparative.pdf.
Повний текст джерелаАнотація:
Airport is one of the most complex facilities which link various business units to achieve their roles within the air transport industry. Individuals travel frequently as they get wealthier. That means economic fortune causes more demand for travel. In the case of aviation industry, this pattern is enhanced by propel innovation, cost efficiencies and solid rivalry inside the business, which have conveyed air travel inside the compass of numerous individuals.
The chief objective of this study is to examine the factors affecting functioning of Mumbai, Pune, Lucknow, Kanpur, Ranchi and Rourkela airports in India and recognize opportunities for improving airport performance. The multiple regression model is applied to find the relationship between demands i.e. number of passengers and its determinants. As the coefficients of factors such as Economic condition, occupation and Income of passenger, Population of the place, Connectivity to other cities, Accessibility to the airport and Safety and security at the airport gets higher values, they affects more in functioning of the airport. In similar way the coefficients of factors such as Place of Residency, Air fares, No. of Airlines in function, Frequency of flights, Airport Infrastructure, psychological parameters (fear of flying, willingness to pay, attitude, etc) gets low values, they affects less in functioning of the airport.
The findings of this study suggest that air transport demand can be enhanced significantly when the price of competing service, population and income increases and airfare decreases. Thus the administrative associations (Airport Authority of India) ought to have a consolidated arrangement to upgrade the benefit acquired through the advancement of the national economy and the population development.
28
V, Akhila. "Application of Artificial Intelligence Techniques in Calibration of Ground Penetrating Radar." Thesis, 2018. http://ethesis.nitrkl.ac.in/9496/1/2018_MT_216CE1039_AkhilV_Application.pdf.
Повний текст джерелаАнотація:
Ground penetrating radar(GPR),an instrument that works by the principle of electromagnetic wave propagation,is of great use for in-situ ground analysis. Its potential uses in the field of geotechnical engineering are not fully explored with sufficient vigour,probably due to economic reasons and highly heterogeneous nature of soil. Taking this into account, if the instrument can be calibrated specifically for geotechnical purposes, it can reduce the number of experimental analyses that needs to be carried on soil and can also reduce the necessity of undisturbed samples of soil to a good extend. The present study discusses the calibration of GPR, through clay content of soil with some of its properties like particle density, bulk density, porosity, void ratio with the dielectric permittivity and peak wave frequency which are obtained from GPR data. Based on the database available in literature, the detection of clay content in three different grades of soil A1,A2 and A3, classified as per American Association of State Highway and Transportation Officials(AASHTO) are done using some recently developed AI techniques, multigene genetic programming (MGGP) and feature selection using NSGA-II, multivariate adaptive regression splines (MARS), Gaussian process regression (GPR)and Support Vector Machine (SVM). The predictive capabilities of these methods are discussed through coefficient of correlation(R2), Nash Sutecliffe coefficient of efficiency (E) root mean square
error(RMSE), average absolute error (AAE) and maximum absolute error(MAE). Based on above statistical parameters, the methods were ranked, for best fit, minimum error and least deviation of mean of actual to predicted values from 1. A combined rank was taken based on these three. It was observed that NSGA –II algorithm trained using ANN is showing better capability for predicting the clay content, with R2 value of 0.97 for both test and train data the least RMSE of 0.77 and 0.65 for test and train data, respectively.Though,the number of data points are limited, the AI methods used could predict the values with very good accuracy.
29
Patnaik, Ashish Kumar. "Entry Capacity Modelling of Roundabouts under Heterogeneous Traffic Flow Conditions." Thesis, 2018. http://ethesis.nitrkl.ac.in/9765/1/2018_PHD_AKPatnaik_513CE1011_Entry.pdf.
Повний текст джерелаАнотація:
The objectives of this study is to develop entry capacity models for both un-signalized and signalized roundabouts under heterogeneous traffic flow conditions. Required data have been collected from 27 un-signalized and 15 signalized roundabouts spanning across 11 states of India. To develop the entry capacity model for un-signalized roundabouts, initially two types of models are developed namely, empirical models and gap acceptance based models. Empirical models are based upon statistical approach whereas gap acceptance models rely on the driver’s behaviour and vehicle-to-vehicle interactions. An empirical model is developed by taking geometric variables and circulating flow as explanatory variables, while the gap acceptance based model is developed by employing critical gap, follow up time and circulating flow as explanatory variables. To reflect the driver behavioral habits and site conditions in a single model, semi-analytical model is developed in this study. In order to reflect the actual driver behavioral habits under local conditions,critical gap and follow up time are estimated by using proposed Influence area for gap acceptance (INAGA) method in this study. The critical gap values found to be varying from 0.54 s to 2.87 s, which are nearly half the values (4 s to 4.6 s) of developed nations like USA and European countries. To ascertain the applicability of proposed INAGA method, the said method is compared with traditionally followed raff and equilibrium of probabilities method. It is observed that the critical gap values estimated by equilibrium of probabilities method differs from corresponding values estimated by INAGA method by 2.10 to 27.03 %. While the values obtained by raff method are quite similar and differ by 0.41 to 3.27 % only. Models based on Artificial intelligence techniques such as Artificial Neural Network (ANN), Generic Programming (GP), Adaptive Neuro Fuzzy Inference Systems (ANFIS) are also developed for un-signalized roundabouts. A comparative study on all developed models is carried out. Also signalized roundabout entry capacity model is developed by using the concept of signalized analogy in which geometric variables and signalization variables are taken as explanatory variables. It has been observed from the collected data set that the Composition of traffic varies as (0.14 to 55.07)%, (10.52 to 78.9)%, (6.84 to 77.9)%, (0.06 to 36.51)%,(0.04 to 7.49)% for heavy vehicles (HV), light motor vehicles (LMV), Motorcycles (MC)/scooters, Bicycles (BC) and Animal drawn vehicles (ADV)/Human drawn vehicles (HDV) respectively at selected un-signalized roundabouts. Similarly, the Composition of traffic varies as(18.92-77.18)%, (2.92- 33.28)%, (11.84-57.58)%, (1.71-11.63)%,(0.41-13.48)%, (0.14-0.78)% and (2.27-26.54)% for two wheelers (2W), Three wheelers (3W), Cars, Light commercial vehicles (LCV), Bus, Truck and Cycle at selected signalized roundabouts respectively. The co-efficient of determination (R2) value of empirical based model and gap acceptance based model are found to be 0.93 and 0.78 respectively. And the p-value in the test of Analysis of variance (ANOVA) is found to be 0.00 (p-value<0.05) for both empirical and gap acceptance based model, which signifies that the models are statistically fit at 95% confidence level. By developing the semi-analytical model, the R2 and p-value in the test of ANOVA are found to be 0.92 and 0.00 respectively. And from the significance test, the value of Nash-Sutcliffe co-efficient (E), mean (μ) and standard deviation (σ) are found to be (0.91, 0.99, 0.13) and (0.87, 0.93, 0.11) respectively which signifies that the proposed semi-analytical model is statistically significant at 95% confidence level. It is observed that Bayesian regularization back propagation training function (TrainBR), in combination with hyperbolic tangent sigmoid transfer function (Tansig) based ANN model has highest R2 value of 0.97 and lowest root mean square error (RMSE) value of 167.89 among all ten models developed. Therefore, this model is chosen for the capacity prediction in this study. Among three developed models such as Genetic Programming (GP), Age layered population structure Genetic Programming (ALPS GP) and Grammatical Evolution Genetic Programming (GEGP); GEGP model is found to be best fit by employing modified rank index (MRI) among these GP based models. By applying multiple non-linear regression analysis (MNLR), the proposed signalized roundabout capacity model is found to be best fit at 95 % confidence level in which the R2 is measured to be 0.95. Sensitivity analysis reported that weaving section variables such as weaving length (Wl), weaving width (WW) and signal phase variable such as green time (G) are major variables for the determination of signalized roundabout entry capacity. Among the proposed un-signalized roundabout entry capacity models such as semi-analytical model, ANN model, GEGP model and ANFIS model; ANFIS model placed in 1st rank, whereas both ANN and GEGP model are placed in 2nd rank and Semi-analytical model is placed in 3rd rank respectively. It is ascertained from statistical test that ANFIS model holds good for roundabout capacity estimation. But from practical application point of view, this model seems to be poor as expression of the equation could not be built up. Whereas, in comparison to ANFIS model, Semi-analytical model can be widely acceptable for its simplicity and manageability. Hence Semi-analytical model is recommended for the estimation of roundabout entry capacity under heterogeneous traffic flow conditions. Regression based models are simple from application point of view but these models have shown higher prediction error in comparison to Artificial intelligence based models. Sensitivity analysis reports that critical gap is the prime variable and sharing 18.43 % in the semi-analytical based roundabout entry capacity model. As compared to Girabase formula (France), Brilon wu formula (Germany) and HCM 2010 models, the proposed semi-analytical model is quite reliable under low to medium range of traffic volumes. The proposed model is suggested for application in the field by practitioners because the model provides unique equation for prediction. The priority of explanatory variables can be easily examined in the proposed model. The model can be easily modified by inclusion or exclusion of geometric variables. The model can be widely acceptable for its simplicity and manageability. Sensitivity analysis is quite useful for planning and design prospective because of major contributing variables are easily identified in the proposed model. The common PCU factors are determined to convert the heterogeneous traffic into homogeneous one, thus it give a reliable estimation of roundabout entry capacity. These findings will be helpful for the researchers, planners and designers for making key decision.
30
Sahu, Roma. "Studies on Ultimate Bearing Capacity of Shallow Foundation Resting over Geogrid-Reinforced Sand under Centric Inclined and Eccentric Vertical Load." Thesis, 2018. http://ethesis.nitrkl.ac.in/9785/1/2018_PHD_RSoma_513CE1003_Studies.pdf.
Повний текст джерелаАнотація:
Since the original work by Binquet and Lee (1975), a number of studies have been conducted to evaluate the possibility of constructing shallow foundations on reinforced soil to increase their load-bearing capacity and reduce settlement. Results of several laboratory model test studies have been published relating to the improvement of the load-bearing capacity of shallow foundations supported by sand reinforced with various materials such as geogrids, geotextiles, metal strips, metal bars, rope fibers etc. The use of geogrid for soil-reinforcement has increased greatly, primarily because geogrids are dimensionally stable and combine features such as high tensile modulus (low strain at high load), open grid structure, positive shear connection characteristics, lightweight and long service life. The open structure provides enhance soil-reinforcement interaction.
Most of the previous studies relate to using geogrid as reinforcement in the soil under foundations subjected to centric and vertical load to evaluate the ultimate and allowable bearing capacities. Based on the review of the existing literature , it appears that no attention has been paid on the load carrying capacity of shallow foundations resting over geogrid-reinforced soil subjected to inclined and eccentric loadings. The objective of this thesis is to study the two aspects namely (i) the effect of load inclination on the load carrying capacity of shallow strip foundation resting over reinforced sand and (ii) the effect of load eccentricity on the load carrying capacity of rectangular foundations.
In order to arrive at the objective and to quantify certain parameters, two sets of extensive laboratory model tests have been conducted. In the first set the ultimate bearing capacity of shallow strip foundation resting over geogrid-reinforced sand bed subjected to inclined load has been determined. These tests have been conducted on dense and loose sand at relative densities of 69% and 35% respectively. The load inclination with respect to the vertical () has been varied from 0 to 20 with increments of 5, whereas the number of geogrid layers (N) varied from 1 to 4. The embedment ratio (Df /B; Df = depth of foundation, B = width of foundation) has been varied from 0 to 1 with increments of 0.5. Based on the model test results, an empirical non-dimensional reduction factor has been developed to estimate the ultimate inclined load per unit area of the foundation under inclined loading if the ultimate bearing capacity under vertical loading is known.
The second set of laboratory model tests have been conducted to determine the ultimate bearing capacity of a surface rectangular foundation resting over multi-layered geogrid reinforced sand with varying width-to-length (B/L; B, L = width and length of the foundation respectively) ratio subjected to eccentric vertical loading. The load eccentricity ratio e/B (e = eccentricity) has been varied from 0 to 0.15 with increments of 0.05, width-to-length ratio (B/L) has been varied as 0, 0.33, 0.5 and 1. Number of geogrid layers varied as 2, 3 and 4. Based on the model test results, an empirical non-dimensional reduction factor has been developed for each (B/L) ratio. A generalized empirical equation has been developed to estimate the ultimate bearing capacity of rectangular foundations resting on geogrid-reinforced sand subjected to eccentric load.
Numerical modelling based on finite element analysis by using plaxis 3D has been conducted to study the effects of number of geogrid layers, relative density of soil, load inclination, load eccentricity, failure mechanism, displacements, plastic flow on the behavior of inclinedly loaded strip foundation and eccentrically loaded rectangular foundation supported by reinforced sand. A close agreement between the experimental and numerical results is observed.
An equation has been developed for reduction factor obtained by ANN that can be used to estimate the ultimate bearing capacity for two different cases of experiments. The results from ANN analysis have been compared with model test results and appear to be good. Based upon the sensitivity analysis important input parameters is findout.
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Giri, Jyoti Prakash. "Development and Evaluation of Bituminous Paving Mixtures Containing Treated and Untreated Recycled Concrete Aggregates." Thesis, 2018. http://ethesis.nitrkl.ac.in/9797/1/2018_PHD_JPGiri_513CE1012_Development.pdf.
Повний текст джерелаАнотація:
With the rapid depletion of resources for natural aggregates, recycling has become very essential for the construction industries. Recycling and resource protection is being encouraged in construction industries, but its application is limited due to several constraints. In the bituminous paving industry, some innovative materials and technologies have been explored to determine their suitability for the design, construction and maintenance of the pavements. Demolition of concrete structures creates a large amount of debris and waste, which is generally called construction and demolition (C&D) waste. The debris that remains after demolition needs to be appropriately reused and not disposed of in landfills. When these C&D wastes are recycled and turned into aggregates for new construction works, these are known as recycled concrete aggregates (RCA).
Use of recycled concrete aggregate in bituminous paving mixtures is limited mainly because of its high water absorption. Therefore, in this study, an attempt has been made to pre-treat the RCA using bituminous emulsion to reduce its water absorption characteristics, which is referred to in this study as pre-treated recycled concrete aggregates (PRCA). Similarly polyethylene is widely used as a packaging material for many items in day-to-day life which after use are converted into waste. One good use of polyethylene is found mainly in packaging of milk. Due to inadequate alternatives for recycling, a large percentage of polyethylene wastes are sent to landfills, which adversely impact the environment because they are not readily biodegradable. Considering the above, an attempt has been made to explore the use of recycled concrete aggregates and waste polyethylene collected from milk packaging (WPMP) in bituminous paving mixtures. In this study, the dense bituminous macadam (DBM) mixtures were prepared using PRCA, RCA and natural aggregate (NA) as coarse aggregates, with two different types of filler, i.e. cement (CM) and stone dust (SD), and with WPMP. The mixtures thus developed were evaluated in terms of various engineering properties such as Marshall test parameters, indirect tensile strength, moisture susceptibility, dynamic modulus, flow number and rutting effects using wheel tracking test. It was observed that the PRCA and RCA mixtures, in general, satisfy the requirements in terms of Marshall test parameters and moisture susceptibility. From the dynamic modulus tests conducted and master curves developed at reference temperature of 21ºC, mixtures with PRCA and WPMP (PRCAP) show higher stiffness values compared to samples prepared with NA and RCA. Also in resilient modulus test, the maximum modulus value has been observed for mixtures prepared with PRCA and cement, modified by WPMP at all three test temperatures. This is followed by mixtures with RCA and cement, modified by WPMP. Cement as filler is found to result in somewhat better engineering properties compared to stone dust. In the present study, after observing various engineering properties of different mixtures, it is concluded that the mixtures with pre-treated recycled concrete aggregates and cement as filler produce comparable results as that with natural aggregates. Further, mixtures prepared with PRCA and cement or stone dust as filler can be used for paving applications considering the superior engineering properties observed through this study. Based on the Indian Roads Congress (IRC) method of flexible pavement design, it is observed that there has been reduction in thickness of bituminous layer made with RCA and/or waste polyethylene. As a result, it is observed that there is a cost saving of 8-10% by using RCA/PRCA and/or waste plastic modification, in respect of a pavement designed on the basis of assumed design inputs for a period of 30 years. Maximum saving is achieved when the DBM mixtures with PRCA are modified by waste polyethylene.
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Mourya, Vishal Kumar. "Non-linear Behaviour of Masonry Infill RC Frame: Influence of Masonry Mechanical Properties." Thesis, 2018. http://ethesis.nitrkl.ac.in/9846/1/2018_MT_216CE2045_VKMourya_Non-linear.pdf.
Повний текст джерелаАнотація:
Unreinforced masonry infilled reinforced concrete frame s are a widespread as part of structural system worldwide. It is common practice to treat the infill as non-structural elements, even the damages noticed during previous earthquakes highlight the effect of masonry infills on the seismic performance of structures . The infills are constructed using a large variety of materials and different construction techniques The detailed literature review has revealed that there are a number infilled RC framed pre-code buildings those are constructed before the seismic code has been introduced. Performance of these gravity load-designed buildings are require d to be assessed considering the effect of infilled masonry. However, the research effort in this direction is found to be limited. Also, the properties of brick masonry are variable in nature as the constituent materials are developed from natural sources involving different types of uncertainty. However, detailed literature review did not reveal adequate research attention to address this issue. Based on the above discussion the main objective of present study are defined as to study the behaviour of gravity load designed infilled RC framed buildings due to change in mechanical properties of infill masonry with and without openings. The result from the present study shows, by keeping value of shear strength of infill masonry constant and increasing its young modulus, the maximum base shear is reached at smaller top displacement and it assumes lower value. The maximum of infilled frame increases with increase in value of for constant. In case of opening, result obtained showing reduction in value of Vb on increasing percentage of opening.
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Mishra, Biraja Prasad. "NURBS-Augmented Finite Element Method for Static, Dynamic and Stability Analyses of Arbitrary Stiffened Plates." Thesis, 2019. http://ethesis.nitrkl.ac.in/10123/1/2019_PhD_BPMishra_513CE1001_NURBS.pdf.
Повний текст джерелаАнотація:
In the present work, a new method coined as NURBS-Augmented Finite Element Method (NAFEM) has been proposed for the static, free vibration and buckling analyses of bare as well as stiffened plates of arbitrary geometries. The idea behind the present formulation originated from the concepts of Isogeometric Analysis (IGA) and NURBS-Enhanced Finite Element Method (NEFEM). In IGA, the geometry and the displacement fields are repre-sented with the NURBS basis function. As the NURBS basis functions are non-interpolating in nature they do not satisfy the Kronecker-Delta property which leads to the difficulty in enforcing the essential boundary conditions. In NEFEM, only the geometry of the elements which are at the boundaries of the plate are represented by NURBS basis function whereas the displacement function of the boundary elements are taken as piecewise polynomials. The rest of the elements which are not intersecting the boundaries are dealt with usual classical finite element techniques. Here in this present work, the NURBS basis functions are incor-porated to represent the geometry and its weakness for representing the field variables is avoided by adopting classical finite element known as ACM (Adini, Clough and Melosh) plate bending basis functions for the field variables. The efficacy of the method is shown by considering examples of various geometrical shapes and boundary conditions for all the analyses of the bare and stiffened plates.
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Samantasinghar, Subhashree. "Utilization of Industrial Solid Wastes for Synthesis of Inorganic Polymer as a Soil Stabilizer." Thesis, 2020. http://ethesis.nitrkl.ac.in/10153/2/2020_PhD_SSamantasinghar_514CE1007_Utilization.pdf.
Повний текст джерелаАнотація:
Soils need to be stabilized to improve its geo-engineering properties before any construction of infrastructures. Conventional soil stabilizers such as cement and lime have environmental issues and uneconomical. Geopolymers are the new generation binder that has attracted considerable interest in modern construction industries due to their high engineering performance, less environmental impacts and cost-effectiveness. An investigation is made to explore the efficacy of geopolymer prepared by sodium hydroxide activated fly ash-slag in stabilizing the granular soil through a set of experimental studies.
The physical, mechanical and chemical properties of geopolymers are greatly influenced by the synthesis parameters. The fresh and hardened properties such as normal consistency, setting time, soundness, drying shrinkage, flow and compressive strength of the geopolymer paste and mortar are reported. The influence of synthesis parameters on the unconfined compressive strength of the geopolymer; synthesized under different processing conditions is investigated. The microstructural analysis is also made to correlate the reaction products with the observed strength. Statistical analyses are carried out to check the significance of the factors affecting the synthesis process. Also, mathematical relationships are established for factors influencing the mechanical behavior of the synthesized geopolymer. The compaction characteristics, unconfined compressive strength, bearing resistance, permeability characteristics, durability under wetting-drying, freezing thawing cycles and decay under chemical attacks of geopolymer modified granular soil are investigated experimentally in order to assess its suitability as a geotechnical construction material. Also, the effect of delayed compaction on density and strength has also been studied. Microstructural analysis has been carried out and correlated with the strength development.
The test results reveal that the dissolution of alumino-silicates is highly influenced by the alkali content and the reactive component of the source material. The experimental results indicated that the physico-mechanical properties of geopolymer binders are similar to that of conventional cement and are greatly influenced by the composition of the source material, concentration of the activator and processing conditions. The major reaction products were the hydrates of calcium and/or sodium based alumino-silicates and those were intensified with curing temperature and duration. Raw materials are optimized by the design of experiment and the fitted model shows a good relation with the experimental data. Based on the test results of geopolymer stabilized soil, a maximum unconfined compressive strength of about 7 MPa is attained. California bearing ratio ranging from 52 to 416% are obtained at different geopolymer contents and curing conditions. The geopolymer stabilized granular soil showed excellent stability against repeated wetting-drying, freezing-thawing cycles, slaking fluid and aggressive chemical environment. The microstructural developments in geopolymer stabilized granular soil are greatly influenced by the geopolymer content and curing period signifying the formation of hydration and geopolymeric reaction products.
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Mamillapalli, R. S. "Impact of Fire on Steel Reinforcement of R.C.C Structures." Thesis, 2009. http://ethesis.nitrkl.ac.in/1546/1/raja_sekhar.pdf.
Повний текст джерелаАнотація:
With the increased incidents of major fires in buildings; assessment, repairs and rehabilitation of fire damaged structures has become a topical interest. This is a specialized field involves expertise in many areas like concrete technology, material science and testing, structural engineering, repair materials and techniques etc. Research and developmental efforts are being carried out in this area and other related disciplines. In this topic the experience of real life problems are presented which add immense value to this. This topic also gives a
comprehensive knowledge on the overall strategy for the restoration of fire damaged buildings and also presents a critical appraisal of the assessment procedures by different non destructive techniques, specifications and execution of repair techniques.
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Bose, Shivam. "Development of an open source toolbox and three dimensional analysis of frame structure under arbitrary loading." Thesis, 2012. http://ethesis.nitrkl.ac.in/3291/1/Thesis.pdf.
Повний текст джерелаАнотація:
As the height of buildings goes on increasing in this modern era, it has become increasingly important to understand their behavior in real life situations. Under such conditions, the building which is idealized as a simple frame comes under various loads and acts both statically and dynamically.Commercial available software package such as STAAD-PRO offers methods and mechanisms to study the behavior of structures under various types of loads which simulate the real-life conditions. The main drawback of such commercial software packages is their high-costs and the inability to modify them according to our own use. The main reason behind the latter is the closed source nature of the software in question.This project aims to perform static analysis on simple frame using the toolbox developed in the MATLAB environment. The project also aims to develop an open source toolbox based in MATLAB environment to perform static and earthquake analysis on simplified frame structures. All the data obtained from the toolbox are compared to that obtained from STAAD-PRO
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Subhash, A. K. "Damage detection in beams." Thesis, 2014. http://ethesis.nitrkl.ac.in/5840/1/212CE2042-2.pdf.
Повний текст джерелаАнотація:
Identification of crack location and depth in structural elements such as beams, columns, and slabs, etc., subjected to time varying loads will help them to retrofit before failure thereby its life and structural capabilities can be greatly improved. It is not always possible to detect the initial cracks by visual inspection. Laboratory test results of isotropic simply supported beam and Cantilever beams with different crack location and crack depths data are collected from literatures as in terms of system natural frequencies and crack locations for single crack and multi cracks. Different models are developed for crack detention using Natural frequencies as Input and Crack Depth and locations as Output. At first an attempt made for simply supported beam having a Single crack detection using Artificial Neural Network (ANN) Model. Different ANN models are developed using different training functions and found Levenberg-Marquartd (LM) fits best among others which is evaluated in terms of R-square value. The Comparison has been made between developed ANN models and regression models. It shows that the ANN models can perform well than regression models. Further the simple equation has been presented for evaluation of crack depth based on the performance of the models developed. Secondly, the problem involves detection of multi crack damage in a Cantilever beam using ANN Model and Response Surface Method (RSM). To achieve better results in RSM higher degree equation is used. The final performances of each model are evaluated in terms of R- value. And, it is found that ANN fits the equation reasonably good. Crack Depth and Crack location can be detected using ANN approaches which may be helpful in retrofitting the structures.
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D, C. Haran Pragalath. "Reliability Based Seismic Design of Open Ground Storey Framed Buildings." Thesis, 2015. http://ethesis.nitrkl.ac.in/6686/1/511CE105_PDF.pdf.
Повний текст джерелаАнотація:
Open Ground Storey (OGS) framed buildings in which the ground storey is kept open without providing any infill walls and mainly used for parking, are increasingly common in urban areas. Vulnerability of this type of buildings has been exposed in the past earthquakes.
OGS buildings are conventionally designed considering a bare frame analysis, ignoring the stiffness of the infill walls present in the upper storeys, which under-estimates the inter-storey drift and the force demand in the ground storey columns. To compensate this, a multiplication
factor (MF) is introduced by various international codes while calculating the design forces (bending moments and shear forces) in the ground storey columns. Present study focuses on the evaluation of seismic performances of OGS buildings designed with alternative MFs through performance-based design approach using a probabilistic
framework. The probabilistic seismic demand models and corresponding fragility curves for all the selected OGS buildings are developed for different performance levels. Reliability curves are developed for the OGS building frames against the seismic hazard associated with
maximum seismic zone of India (Zone-V of IS 1893, 2002). Similar analyses are also carried out on bare frames and fully infilled frames for reference. It is found from the present study that the application of MF only in ground storey, as suggested by many literatures and design codes (including Indian standards), is not an appropriate solution for design of OGS buildings as it leads to vulnerable adjacent storey. This study proposes an effective scheme of MF for design of OGS buildings that yields acceptable levels of reliability index.
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Routray, Sharmili. "Shear Behaviour of BFRP Strengthened RC T-Beams." Thesis, 2015. http://ethesis.nitrkl.ac.in/6972/1/2015_Sharmili__Mtech(R)_612CE3006.pdf.
Повний текст джерелаАнотація:
Deterioration in reinforced concrete structures is a major issue faced by the infrastructures and bridge industries all over the world. Since complete replacement of these structures requires high investment, strengthening has become the suitable solution to modify and improve the performance of the structures. Previously steel plates were used as external reinforcement to strengthen deficient RC structures, but in the last fifteen years or so on, FRP composites have been used to replace steel because of their superior properties. RC T-section is the most common shape of beams and girders in buildings and bridges. Shear failure of RC T-beams is identified as the most disastrous failure mode as it does not give any advance warning before failure. The shear strengthening of RC T-beams using externally bonded (EB) FRP composites has become a popular structural strengthening technique, due to the well-known advantages of FRP composites such as their high strength-to-weight ratio and excellent corrosion resistance. This study explores the result of an experimental investigation for enhancing the shear capacity of reinforced concrete (RC) T-beams with shear deficiencies, strengthened with Basalt
Fiber Reinforced Polymer (BFRP) sheets which are a relatively new and economic alternative to more expensive fibers commonly used in strengthening of RC beams. A total of 22 numbers of concrete T-beams are tested and various sheet configurations and layouts are studied to
determine their effects on the shear capacity of the beams. One beam of the beams is considered as control beam, while other beams are strengthened with externally bonded BFRP sheets/strips.
To accommodate essential services like electricity cables, natural gas pipes, water and drainage
pipes, air-conditioning, telephone lines, and computer network transverse web opening are necessary in modern building construction. Hence, the present study investigates the shear behaviour of RC T-beams with different types of transverse web openings. The various
parameters investigated in this study included BFRP amount and distribution, bonded surface, number of layers of BFRP, fiber orientation, transverse web openings of different shape (i.e., circular versus square versus rectangular) and end anchor. The experimental results demonstrated that the use of the new mechanical anchorage scheme comprising of laminated composite plates increases the shear capacity of the beams significantly by preventing the debonding of BFRP sheets, so that the full strength of the BFRP sheets get utilized. An analytical study is also carried out to validate the experimental findings.
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Sahoo, Kirtikanta. "Studies on Concrete Made of Recycled Materials for Sustainability." Thesis, 2016. http://ethesis.nitrkl.ac.in/8478/1/2017-PhD-KSahoo-512CE1005.pdf.
Повний текст джерелаАнотація:
Construction industry uses Portland cement which is known to be a heavy contributor to the CO2 emissions and environmental damage. Incorporation of industrial wastes like demolished old concrete, silica fume (SF) and fly ash (FA) as supplementary cementing materials (SCMs) could result in a substantial reduction of the overall CO2 footprint of the final concrete product. However, use of these supplementary materials in construction industry especially in the making of concrete is highly challenging. Significant research efforts are required to study the engineering properties of concrete incorporating such industrial wastes. Present research is an effort to study the properties of concrete incorporating industrial wastes such as demolished concrete, SF and FA.
Recycled coarse aggregate (RCA) concrete construction technique can be called as ‘green concrete’, as it minimizes the environmental hazard of the concrete waste disposal. Indian standard recommends target mean compressive strength of the conventional concrete in terms of water cement ratio (w/c). The behaviour of RCA concrete, prepared from two samples of parent concrete having different age groups, is investigated, to propose the relationship of compressive strength with water cement ratios, in the present study. Number of recycling may influence the mechanical properties of RCA concrete. The influence of age and number of recycling on the properties such as capillary water absorption, drying shrinkage strain, air content, flexural strength and tensile splitting strength of the RCA concrete are examined. While the compressive strength reduces with number of recycling gradually, the capillary water absorption increases abruptly, which leads to the conclusion that further recycling may not be advisable.
Previous studies show that the properties of RCA concrete are inferior in quality compared to NCA concrete. The improvement of properties of RCA concrete with the addition of two ureolytic-type bacteria, Bacillus subtilis and Bacillus sphaericus to enhance the properties of RCA concrete. The experimental investigations are carried out to evaluate the improvement of the compressive strength, capillary water absorption and drying shrinkage of RCA concrete incorporating bacteria. The compressive strengths of RCA concrete are found to be increased by about 20% and 35% at the cell concentrations of 106 cells/ml for the two bacteria. The capillary water absorption as well as drying shrinkage of RCA are reduced when bacteria is incorporated. The improvement of RCA concrete is confirmed to be due to the bacterial mineral precipitation as observed from the microstructure studies such as EDX, SEM and XRD.
The mechanical properties, such as compressive, flexural and tensile splitting strength, of SF concrete considering the 10% additional quantity of cement as recommended by International codes, by partial replacement of slag cement on low to medium strength concrete, have not been investigated so far. The present study investigates the mechanical properties of medium strength SF concrete made as per this construction practice by partial replacement of slag cement. Effect of SF on compressive, flexural and tensile splitting strength of hardened concrete is examined. Seven concrete mixes are prepared using Portland slag cement (PSC) partially replaced with SF ranging from 0 to 30%. The mix proportions were obtained as per Indian standard IS: 10262-2009 with 10% extra cement when SF is used as per the above the construction practice. Optimum dosages of SF for maximum values of compressive strength, tensile splitting strength and flexural strength at 28 days are determined. Results of the present study are compared with similar results available in literature associated with Portland cement. Relationships, in the form of simplified equations, between compressive, tensile splitting and flexural strengths of SF concrete are proposed.
Several studies related to sustainable concrete construction have encouraged the usage of industrial waste products such as SF and FA. Design of structures, made using such SF and FA concrete, for an acceptable level of safety, requires the probabilistic descriptions of its mechanical properties. For this purpose, an extensive experimental programme was carried out on compressive strength, flexural strength and tensile splitting strength properties of SF and FA concrete. The probability distribution models are proposed based on the three goodness-of-fit tests such as Kolmogorov-Sminrov, Chi-square and log-likelihood tests. The proposed probability distributions are used to study performance of typical buildings made of SF and FA concrete through seismic fragility curves and reliability indices.
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Behera, Baishnu Bhusan. "Assessment of lime stabilized slag- fly ash mixes as a highway material." Thesis, 2017. http://ethesis.nitrkl.ac.in/8726/1/2017_MT_BBBehera.pdf.
Повний текст джерелаАнотація:
The objective of the thesis is to use industrial wastes rather than natural soil, aggregates, etc. in roads and highway construction after enhancing its strength, stability and durability. Conventionally, soil, stone aggregates, sand, bitumen, cement etc. are used in construction of roads and highway. Characteristic materials being limited in nature and thereby need of alternate materials is necessary. Gigantic quantities of soil are utilized as a part of the development of street and parkway yet adequate quantity of soil of required quality is not available effectively. To meet this demand extensive deforestation is being done which cause deforestation, soil disintegration and loss of rich soil which hampers in the farming efficiency. Additionally, cost of procurement of suitable quality of material is increasing. Worried about this, the researchers are searching for option materials for thruway development, and modern waste item is one such class. Stabilization method highlighted in this thesis is mainly to enhance the inherent strength of wastes like fly ash and crushed blast furnace slag (CBFS). This will automatically reduce the use of natural soil in addition to mitigate the disposal problems of industrial solid wastes in a great way. Fly ash and blast furnace slag was collected from Rourkela steel plant (RSP). Tests were conducted by blending fly ash and blast furnace slag in different proportions. The compaction characteristics, strength properties and the bearing value of different mixes are determined. From the compaction tests the optimum moisture content and the maximum dry density are determined for respective mixes. The strength parameters that are the unconfined compressive strength and CBR value for different mixes compacted to their respective MDD at OMC are evaluated. Further these mixes are blended with lime varying as 0%, 2%, 4%, and 8% and the UCS values are determined after a curing period of 0, 7 and 28 days. Similarly, the soaked CBR values of lime stabilized mixes at 0%, 2%, 4%, and 8% are determined after a curing period of 0 and 28 days. The effect of lime, curing period, fly ash and slag content with the unconfined compressive strength values and California bearing ratio values were studied. From the experimental study, it was observed that with addition of blast furnace slag to fly ash- slag mixes, the MDD increases and thereby decreases its OMC value linearly. It was also observed that the UCS value of the fly ash- slag mixes increases with the addition of slag up to slag content of 80% and there after the same decreases with further increases in slag content. The mix with 80% slag shows higher value as compared to 100% slag in the mix. Similar trend was observed for the CBR value for the fly ash- slag mixes, and it was seen that with increase with the slag content the CBR values also increases. However, for 100% slag the CBR shows a lesser value. Higher UCS and CBR values were reported at 8% lime content having a curing period of 28 days. The objective of the present study is to access the suitability of lime stabilized fly ash- blast furnace slag mixes as a highway construction material. So it is concluded that appropriate blending of fly ash with slag gives a better strength compared to individual materials. Further the desired strength required for different component of road can be achieved by stabilizing the mix with appropriate amount of lime.
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Mallick, Monalisa. "Experimental and Numerical Investigation of Wind Induced Pressure on C-shaped Building Models." Thesis, 2020. http://ethesis.nitrkl.ac.in/10152/1/2020_PhD_MMallick_514CE1014_Experimental.pdf.
Повний текст джерелаАнотація:
Wind induced forces are significant for buildings and therefore their impact on such structures is essientally required during their design and analysis. For analytical solution of the wind load, estimations of the wind pressure coefficients on its faces are the pre requisite. Generally, there are three primary methods which are used to estimate pressure coefficient: full-scale building tests, model test in wind tunnel and parametric equations derived from experiments. Buildings shapes are changing with emerging demands of several aesthetical features. Developments of new building materials and construction techniques have enabled us to build new building, which are tall and unsymmetrical (irregular) but unfortunately such structures are susceptible to more complex wind loads. Thus, it becomes necessary to estimate the wind loads with higher degree of confidence. Although ample information regarding wind load on symmetrical and regular structure is available in various international codes, but they lack the study of wind forces on unsymmetrical structures.
Literature provides some information on L, T, E, Y, N, Plus (+) and also on U-shaped building plans with flat surface only i.e., without curvature. Although, there are many C-shaped buildings that exist in real practice, no work has been reported for C-shaped building models with variation in curvature. Wind pressure on the structures is affected by its geometry, the nature of the corner (with or without curvature), incidence angle of wind and flow features. The present work focuses on the outcome of experimental investigation of mean pressure coefficients on different faces of C-shaped building models. Distribution of wind pressure coefficient on the surfaces of C-shaped buildings models (irregular plan) through numerical and physical modelling are attempted. Experiments have been carried out on the different C-shaped building models with and without corner curvature along considering some other variables such as the angle of incidence, side ratio, frontal ratio and aspect ratio in a subsonic open circuit wind tunnel. All the experiments have been carried out at the Aerodynamics laboratory of the Department of Aerospace Engineering, Indian Institute of Technology Kharagpur (IITKGP), India.
One way to accurately estimate the wind pressure coefficients on the surfaces of C-shaped building is their model testings in a wind tunnel. The building models were made of 5 mm thick Perspex sheets. Recorded data of pressure at the located pressure taping points enabled to determine the pressure coefficient variation on the surfaces with wind angles and corner curvature. It has been observed that the pressure coefficient at a location on a surface varies significantly with the angle of incidence and the curvature of the surfaces. Also, the extent of (xii)
maximum and minimum pressure zones, and their locations have been observed to change with the curvature and the wind direction.
This work also presents numerical analysis through Computational Fluid Dynamics (CFD) technique to calculate wind effect used C-shaped buildings with varying aspect ratio and its optimization caused by the alteration of angle of incidence of the wind forces ranging from 00 to 1800 at an interval of 300. Further, results obtained through numerical simulation have been validated with the corresponding experimental results. Numerical analysis has been carried out using ANSYS Fluent with k-ε model of turbulence. This suggests the applicability of this technique to predict the wind pressures on the surfaces of the prototype building more accurately.
Further, analytical equations are developed for determining surface mean pressure coefficient (𝐶𝑝̅̅̅) on the face of the building structures using relevant experimental data obtained from laboratoary experiments. Various data driven techniques or artificial intelligence techniques such as group method of data handling neural network (GMDH-NN), multivariate adaptive regression spline (MARS) and gene-expression programming (GEP) approach are used to develop model equations of surface mean pressure coefficient (𝐶𝑝̅̅̅) using the non-dimensional parameters such as the side ratio, height ratio, curvature ratio, and wind incidence angle. Influence of each parameter for predicting the surface mean pressure coefficient on the surfaces of different C-shaped building models by the developed equations are tested through sensitivity analysis. Performance of all the developed models are evaluated by means of various statistical measures such as coefficient of determination (R2), root-mean-square-error (RMSE), mean absolute error (MAE), the mean absolute percentage error (MAPE), coefficient of efficiency (E), Akaike Information Criterion (AIC), and Scatter index (SI) and uncertainty analysis to determine the best predictable model equation. These developed model equations through GMDH-NN, MARS and GEP approaches can be used as a practical tool for the prediction of surface mean pressure coefficient (𝐶𝑝̅̅̅) on the face of the prototype buildings.
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Kamalakkannan, S. "Utilisation of Fly Ash in Structural Concrete for Sustainable Construction." Thesis, 2016. http://ethesis.nitrkl.ac.in/9178/1/2016_MT_SKamalakkannan.pdf.
Повний текст джерелаАнотація:
Our industrial world produces huge quantities of fly ash, which is a waste and need to be disposed safely or else it can cause disastrous consequences. The disposal of fly ash has been causing a headache to the environmentalists across the globe. Fly ash is a high pozzolanic industrial waste which has the substantial potential to substitute Portland cement, a major producer of CO2 and thereby decreasing greenhouse gas emissions. The production of fly ash is increasing in every year but the utilisation of fly ash is not even half of the production of fly ash. The effective utilisation of fly ash is restricted only to manufacture of bricks, producing fly ash based pozzolanic cement and use in pavements. To utilise the fly ash in high volume the innovative idea is fly ash used as a replacement material for cement and fine aggregate in structural concrete like RCC beam, concrete paver blocks, making fly ash pellets and fly ash angular aggregate.
Concrete paver blocks are being used for various purposes like paving of approaches, paths, parking places and footpaths. They also find their application in roadways or pavements. The increasing costs of construction or building materials and the need to meet sustainable development, different alternative construction methods, techniques and materials are being used extensively to replace old conventional methods. So as to enhance and improvise the applications of concrete paver blocks, proper knowledge and understanding of the products produced with materials, which are available locally and mineral admixtures, which are produced indigenously is essential.
This paper discusses sand replacement with fly ash, coarse aggregate replacement with fly ash pellets in low grade concrete, cement and sand replacement with fly ash in high grade concrete paver blocks. For low grade of concrete, the mix design was prepared for M20 concrete as per IS method. Sand was replaced partially with fly ash up to 60% by weight. To know the effect of sand replacement compressive strength, flexural strength, split tensile strength at 7 and 28 days are studied and optimum percentage of replacement noted. Then RCC beam casted with optimum percentage of sand replacement for flexure failure and behaviour compared with control concrete beam. Again the 10mm coarse aggregate were replaced up to 100% and compressive strength of cubes were studied. The mix design was done for M20 grade of concrete for light weight concrete beam with fly ash pellets without granite aggregate, compressive strength of cubes and behaviour of flexural failure of RCC beam studied and compared with conventional concrete beam.
Finally, the mix design was done for high grade concrete paver block by considering medium traffic. For the medium traffic the grade of concrete considered is M40. The shapes of the paver block considered in this project are Zig zag (60mm), Zig Zag(80mm), Dumbel (60mm), Rectangle(60mm), I(60mm), Pentagon(80mm). Sand replaced by fly ash source of steel plant sambalpur up to 40% and the corresponding 7 and 28 days compressive and flexural strength, water absorption, Durability (Freeze thaw test) characteristics were studied and compared with conventional control mix concrete. Similarly cement replaced by fly ash source of steel plant Dhenkanal up to 40% and the corresponding 7 and 28 days compressive and flexural strength, water absorption, characteristics were studied and compared with conventional control mix concrete.
The experimental results indicate there is significant improve in strength characteristics over control concrete when sand replaced by fly ash source of Bushan steel plant sampalbur up to 30% in low grade concrete and sand replaced by fly ash source of Bushan steel plant sampalbur upto 30% and cement replaced by fly ash source of Bushan steel plant Dhenkanal up to 40% in high grade concrete paver block. Since the fly ash is used for sand replacement it reduces the depletion of mineral resources and used for cement replacement it reduces the production greenhouse and makes sustainable environment.
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Swain, Janaki Ballav. "Streamflow Estimation in Ungauged Catchments through the Process of Regionalization." Thesis, 2018. http://ethesis.nitrkl.ac.in/9398/1/2018_PhD_JKSwain_513CE1007_Streamflow.pdf.
Повний текст джерелаАнотація:
Precise and dependable long-term streamflow record is a vital component in the modelling of hydrologic cycle. Quantitative and qualitative information regarding streamflow is needed for several practical application intended at various locations. However, lack of historical streamflow records makes its prediction in ungauged catchments a daunting task. Most of the catchments present across the globe are either partially gauged or completely ungauged. The scenario worsens in case of developing countries. The subject of ‘prediction in ungauged basins’ (PUB) is not prevalent in India. Regionalization is an alternative way for streamflow prediction in ungauged catchments. The present study deals with few regionalization approach for daily streamflow estimation in thirty-two identified catchments located in the Eastern and Southern India. The first category of regionalization i.e. hydrologic model-dependent approach is carried out using spatial proximity [Inverse Distance Weighted (IDW), Kriging and Global mean], regression analysis and physical similarity in conjunction with Soil and Water Assessment Tool (SWAT) for streamflow estimation in each catchment considered as ungauged in turn. The other type is hydrologic model-independent regionalization which is carried out using Flow Duration Curve (FDC). Area-Index, IDW, Kriging and regression analysis are the techniques used for information transfer from donor to receiver catchments. IDW and Kriging are the two techniques based on geographical distance between gauged and ungauged catchments produced superior results among all the implemented techniques in terms of Nash-Sutcliffe efficiency (NSE), Root Mean Square Error (RMSE)-observations standard deviation ratio (RSR) and Percent Bias (PBIAS). SWAT based regionalization techniques displayed better capability for capturing the variation in daily streamflow than regional FDC based approach. However, Information transfer between dissimilar catchments is likely to produce inaccurate results. Hence, linear [Principal Component Analysis (PCA) along with K-means clustering] and nonlinear [Self-Organizing Map (SOM) and Kernel PCA] classification techniques are executed to distribute the thirty-two catchments into few homogeneous groups based on the catchment attributes. SOM techniques performed best among all in classifying the catchments into four suitable groups. The potential impact of catchment classification on
streamflow regionalization is checked using the best two techniques i.e. IDW and Kriging on both classified and unclassified catchments. Half of the catchments exhibited more than 10% improvement in results when regionalization techniques are applied on classified catchments rather than unclassified ones. The overall outcome of the study proposes that application of suitable hydrological model, regionalization approach and catchment classification technique in an organized manner may produce reliable results in ungauged catchments with less uncertainty. Application of regionalization approaches considering the peripheral environment stationary may produce erroneous results. Thus, the impact of ever-changing Land use/Land cover and variable climate on streamflow regionalization is explored using IDW and Kriging technique in conjunction with SWAT. The outcomes suggest a substantial impact of these two factors on streamflow prediction. Hence, it is recommended to consider the non-stationary factors during the course of regionalization.
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Singh, Anshuman. "A Parametric Study of Slope Stability and Comparison of Breach Parameter for Different case of Earthen Dam." Thesis, 2018. http://ethesis.nitrkl.ac.in/9487/1/2018_MT_216CE1037_ASingh_Parametric.pdf.
Повний текст джерелаАнотація:
The slope stability analysis of earthen dam for every aspect is very crucial because huge risk is related to dam at every stage of construction and working period. The very huge volume of water stored in reservoir by dam, which is very hazardous to downstream location for worst-case scenarios at time of breach in dam. Therefore, stability of dam and breach scenarios is very important to analyze for better solution for dam construction technique. Stability of dam depend upon stress occur in different loading condition, strength of material, geometric parameter, type of foundation and equipment installed. In this study, comparison of downstream slope stability by varying material property of dam and slope of downstream of dam. The effect of core seize, shape, inclination and position on stability of dam. Factor of safety obtained from limit equilibrium and finite element method are compared for various case of dam. In addition, dam break analysis is done for comparing the effect of different breach parameter equation on downstream breach flood. In breach analysis of dam, type of dam and failure mechanism of dam also effect downstream breach flood is also studied.
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Gurmaita, Shival Kumar. "An Experimental Investigation on Braided Channel Pattern Due to Variation in Discharge." Thesis, 2018. http://ethesis.nitrkl.ac.in/9488/1/2018_MT_216CE4082_SKGurmaita_Experimental.pdf.
Повний текст джерелаАнотація:
Sediment transport rate is measured in a laboratory flumeand measurements are evaluated and compared with previous studies.Sediment transport rate is highly variable withtemporally, despite the constant water discharge and Some valueare repeatedregularity in the timing of fluctuations. Sediment transport rate also varied with discharge but this variation is not linear variations. After comparing the sediment transport rate value measured in the laboratory, and sediment transport rate is computed with the different approaches Einstein modal is moreor less similar.Experimental investigation has been carried out in an open channel flow with sand bed surface of grain size of D50values 0.75 mm bed load conditions.We observedthat total braided intensity is always more than active braided intensity and with increase the discharge both are increases .in channel, onlysome parts are active in which sediment bed load moves. New small channels are formedwith time by erosion,sedimentation andchanges in sinuosity of main active channel to forms braided network. Due to regime properties of river both total braided intensity and active braided intensity become stablefor a given channel forming discharge. When we increase discharge, movementof sediment also increases due to this active braided intensity adjusts quickly. We find that the ratio of active braided intensity and total braided intensity gradually approaches to stable value 0.4-0.5 means that at a time both branches havewater butsediment transported in one branch.
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Sunil, Pidathala. "Gate Operations of Multi-Purpose Rengali Dam for Flood Management in Downstream Areas." Thesis, 2018. http://ethesis.nitrkl.ac.in/9543/1/2018_MT_216CE4092_PSunil_Gate.pdf.
Повний текст джерелаАнотація:
Problems and opportunities change over time. Just as the goals of managing and using water change over time, so do the processes of planning to meet these changing goals. Planning processes evolve not only to meet new demands, potential and objectives, but also in response to new insights of how to plan reservoir and gate operation more effectively.
Reservoir operation is a multifarious problem that involves many decision variables, multiple objectives as well as considerable risk and uncertainty (Oliveira
and Loucks, 1997). In addition, the incompatible objectives lead to significant challenges for operators when making operational decisions. Traditionally, reservoir operation is based on heuristic measures, embracing rule curves and prejudiced judgements by the operator. This provides general operation strategies for reservoir releases according to the current reservoir level, hydrological conditions, water demands and the time of the year.
Established rule curves, however, do not allow a fine-tuning (and hence optimization) of the operations in response to changes in the widespread conditions. Therefore, it would be
valuable to ascertain an analytic and more systematic approach to reservoir operation, based not only on traditional probabilistic/stochastic analysis, but also on the information and prediction of extreme hydrologic events and advanced computational technology in order to increase the reservoir's efficiency for balancing the demands from the different users.The main contribution of the thesis is the development of the MIKE 11 Structure Operation (SO) module is being set up to describe the present and future reservoir operation of the Rengali Dam in the Bramhani river basin. The SO module is applied whenever the flows through spillways and sluice gates are regulated by operation of movable gates or controlled directly as in turbines and pumps. The operation rules are applied via a number of logical statements combined with Control Strategies as per the existing operation rule curves.
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Das, Bhabani Shankar. "Non-uniform flow modelling in compound channels with non-prismatic floodplains." Thesis, 2018. http://ethesis.nitrkl.ac.in/9777/1/2018_PHD_BSDas_514CE1015_Nonuniformpdf.pdf.
Повний текст джерелаАнотація:
This research examines the flow in compound channels with non-prismatic floodplain through physical and mathematical modelling which are significant for understanding the non-uniform flow and its behaviour. Accounting the momentum exchange at the junctions of a non-prismatic compound channel is a complex task in order to develop an improved model for predicting stage-discharge relationship, distribution of the flow in subsections, resistance relationship, water surface profile variation and depth averaged velocity distribution.
In literature, much of experimental research works are found to be investigated on prismatic compound channels and less for non-prismatic cases whereas very rare works has been done particularly in non-prismatic compound channel with diverging floodplains. So experiments have been conducted on diverging compound channels in order to investigate the variation of depth averaged velocity distribution, boundary shear stress distribution, stage discharge relationships, flow resistance coefficient, water surface profile and flow distributions in floodplain and main channel (both upper and lower main channel) with different geometric and hydraulic parameters. With these channels, both converging and diverging compound channels have been analysed by studying the data of other researchers. The effectiveness of Manning’s n, Darcy- Weisbach f and Chezy’s C are analysed for the different flow configurations of a non-prismatic compound channel. Manning’s roughness coefficient considered to depend on the non-dimensional parameters like width ratio, aspect ratio, relative flow depth, angles (diverging and converging angles), relative distance, bed slope, Reynolds number and Froude number. A multivariable regression model has been developed by taking care of the aforementioned geometric and hydraulic parameters to predict the Manning’s roughness coefficient for non-prismatic compound channels. The non-linear regression models are developed using relevant experimental data obtained from laboratory experiments and the data from other researchers on the compound channel with non-prismatic floodplains. The present model is found to provide satisfactory results as compared to other approaches for different experimental channels and field data by providing less error.
In a compound channel, vertical apparent shear exists on the interface between the main channel and the floodplain, which generally accelerates the flow on the floodplain and resists the flow in the main channel. In addition, a horizontal apparent shear stress also occurs on the interface between the upper and lower main channels, which generally accelerates the flow in the lower one and resists the flow in the upper one. Therefore, it is essential to consider the exchanges of momentum at both vertical and horizontal shear layer regions. In this thesis, an attempt is made to extended the classical independent subsection method (ISM) to determine the magnitudes of flow and velocities in both upper and lower main channels. Four subsections are created in improved ISM according to the vertical and horizontal division lines that correspond to the vertical interface between the main channel and floodplain and the horizontal interface between upper and lower main channels respectively. The extended ISM consists in a set of four coupled 1D momentum equations (instead three equations of classical ISM) for subsections and a mass conservation equation for the total cross-section. The computed results show that the method is well capable of predicting the discharge distributions in the floodplain and main channel (both at upper and lower main channel) of non-prismatic compound channels.
The use of lateral distribution method (LDM) and its modifications in the computation of depth-averaged velocity distribution in a compound channel for both diverging and converging floodplains has also been performed. The modification of LDM has been done considering the friction slope and secondary current effect. Finite difference scheme has been used for discretizing the Modified LDM. MATLAB tool is used to write the code to compute the depth averaged velocity. Different non-prismatic compound channels having converging and diverging flood plains have been considered to evaluate the strength of Modified LDM over other numerical approaches like LDM and Shiono-Knight method (SKM).
Water level determination during flood is always a challenging task for river engineers. As the floodplain width of a non-prismatic compound channel, changes gradually and moves away from the main channel. Therefore, the prediction of water surface profile becomes complicated. The dependency of water surface profiles on five different non-dimensional parameters such as diverging angle, relative depth, relative distance, width ratio, and aspect ratio are analysed. A multivariable regression model has been developed to predict the water surface profile for diverging compound channels. Using the relevant experimental data, non-linear regression has been performed. The results obtained from the present water surface profile model shows good agreement with the observed data and the other researcher’s data-sets. Various statistical error analyses are performed to verify the reliability of the developed multivariable regression model. Water surface profile prediction is an important task in flood risk management in the urban area. In the present research, based on the principle of the momentum balance a numerical method is investigated to predict the water surface elevations in compound channels with both diverging and converging floodplains. Experimental data series of such channel are collected from literature for different geometry and flow conditions to verify the present model. Various existing flow distributions equations are used in the developed numerical method to estimate the water surface elevation. Finite difference method is used to solve the numerical model using MATLAB tool. The results obtained from the simulation show a good agreement with the experimental datasets. Statistical error analysis has been performed to verify the strength of the present model and the other prevailing water surface profile models. As in many cases the predictive capability of mathematical models fails especially in complicated river geometry cases, so the popular soft computing techniques such as ANN and ANFIS has also been successfully tested. Among these two models the ANFIS model is found to provide a higher value of coefficient of correlation and minimum error in terms of mean square error, mean absolute percentage error.
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Kumar, Abhishek. "Studies on Effect of Wind Induced Pressure on Varying Front and Lateral Faces of ‘C’ Shape of Building." Thesis, 2018. http://ethesis.nitrkl.ac.in/9864/1/2018_MT_216CE4086__AKumar_Studies.pdf.
Повний текст джерелаАнотація:
Due to unavailability of land and considering the architectural aspect now a days buildings are constructed as irregular in plan. The wind force act in a different manner according to the plan of the buildings. So it is the prime concern to study wind force or more precisely the wind pressure on irregular plan shaped tall buildings. To solve this issue comprehensive study has been carried out in this research paper. This paper demonstrates the variation of pressure coefficient on C plan shape model with varying frontal and lateral dimension. This study has been carried out experimentally on C shape model made of perpex sheet in a subsonic low speed wind tunnel .The numerical analysis is carried out with the help of CFD. Mean wind pressure coefficient on different faces of the buildings for different angle of incidence between 0 ͦ to 180 ̊at an interval of 30 ̊ are determined using wind tunnel test. Fluctuating values of wind pressures are measured at various tapping points on all surfaces of models and mean, maximum and minimum values of pressure coefficients are evaluated. The accuracy of the numerically predicted results is measured by comparing results predicted by CFD with experimental results and it seems to have a good agreement with wind tunnel results. Besides wind pressures, wind flow patterns are also obtained by CFD for all the wind incidence angles. These flow patterns predict the behaviour of pressure variation on the different faces of the building. For better comparison of the results, pressure contours on all the faces are also predicted by both the methods. Certain faces were subjected to peculiar pressure distribution due to irregular formation of eddies caused by the separation of wind flow. k-є models were used for numerical study to simulate the wind flow. . The position and magnitude of the measured peak pressure co-efficient vary considerably with wind direction. It is also observed that varying the plan dimensions considerably affects the wind pressure distributions on different faces of the building models.The effectiveness of the model shape in varying the surface pressure distributions is assessed over an extended range of wind directions.
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Pradhan, Arpan. "Stage-Discharge Modelling of Meandering Compound Channels with Differential Roughness." Thesis, 2019. http://ethesis.nitrkl.ac.in/10065/1/2019_PhD_APradhan_514CE1001_Stage.pdf.
Повний текст джерелаАнотація:
Laboratory experimentations concerning stage-discharge and bed shear stress distribution have been carried out in two sets of meandering compound channels with crossover angles 110_ and 60_ constructed by ‘sine-generated’ curves over a flume of width 4 m. The 110 channel has a very high sinuosity of 4.11, much higher than the available maximum sinuosity of 2.54 in literature. The bed roughness in the floodplain and main channel of the 110 meandering channel is each varied twice in order to obtain a combination of three differential roughness conditions. Variation in bed material is undertaken, not just for the floodplain as is usually provided in literature but also for the meandering main channel.
Velocity profiles across the meander path of the 110_ meandering channel are observed, to analyse the effect of different bed roughness on the profiles. Bed shear stress distribution at the apex section of the 110_ channel is examined for the three different roughness combinations. Shear stress along an entire meander path for the floodplain condition of60_ channel is also analysed. The boundary shear stress study illustrates the position of maximum shear along the apex section as well as across the meander path. These variations are observed for different flow depth. The percentage of shear force shared by the main channel and floodplains is studied with respect to the effect of flow depth and the change in bed roughness which aids in determining apparent shear stress along with the momentum transfer between the main channel and floodplains.
Discharge prediction methodologies have been evaluated in this thesis based on
three different approaches; i.e. by determination of the overall roughness coefficient in meandering compound channel; by evaluation of the percentage of shear force shared by the floodplains, and by balancing the forces acting on the different zones of a compound meandering cross-section. Stage-discharge modelling of a meandering compound channel is complex as compared to a straight compound or simple meandering channels. So an attempt has been made to model the overall roughness coefficient in meandering compound channels. The overall roughness coefficient is observed to be dependent on parameters such as relative flow depth, width ratio, Reynold’s number, Froude number, sinuosity, roughness ratio between the floodplain and the main channel and bed slope. Two methodologies are adopted for the prediction of overall roughness coefficient, i.e. by dimensional analysis and the other by a computational methodology, Multi-Gene Genetic Programming (MGGP). The dimensional analysis model provides a dimensionally homogeneous equation undertaking different parameters while the MGGP model provides an expression for Manning’s n with excellent predictability. These models have been compared with other methods of discharge prediction and even validated with river datasets.
The percentage of shear force carried by the main channel and floodplains for the case of meandering compound channels with percentage of apparent shear force at the various interfaces is studied. A model is developed to further predict the percentage of shear force carried by the floodplain which is employed in an improved channel division method to predict the discharge capacity for the case of meandering compound channels with differential roughness.
The momentum transfer coefficient at the interacting interfaces of a meandering compound channel is analysed. The meandering compound channel is divided into four zones with respect to the interfaces, i.e. the horizontal interface between the lower main channel and the floodplain; and the two vertical interfaces at the meander belt width dividing the outer floodplains from the belt. Force balance in these zones is analysed and, the zonal velocity is obtained, which helps in the evaluation of the individual discharge of the zones.
Momentum transfer coefficient of value, _T =0.01 is proposed for meandering compound channels with respect to the datasets undertaken. Procedure for the calibration of _T is also illustrated for the case where stage-discharge data is known. MGGP technique is used to model an expression for _T , for the undertaken datasets from literature. Within the range of datasets used, this model expression is proposed to predict the momentum transfer coefficient for meandering compound channels for different geometric and hydraulic parameters which in turn has been used to predict the discharge capacity as well as the discharge distribution between the channel subsections.
Popular conveyance prediction models along with the proposed model are applied to the experimental datasets to substantiate predictability of the MGGP model. Validation of the model is done for the new experimental data as well as in natural rivers to justify its predictability in field study.