PhD Theses (Civil Engineering)


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Now showing 1 - 20 of 227
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    Snow/Glacier Dynamics of Himalayan Ranges and Associated Hazards
    (2023) Mondal, Sandeep Kumar
    The Himalayan cryosphere, also termed “the Third Pole, " acts as a natural storehouse to several mega river systems, such as the Ganges, Indus, and Brahmaputra, serving billions of people with fresh water. However, the high mountain ranges of the Himalayas are also susceptible to various categories of hazards, such as snow/rock-ice avalanches, landslides, earthquakes, and glacial lake outburst floods (GLOFs). The present study attempts to perform a series of investigations to better understand the dynamics of snow/glaciers in the Himalayan region and their contribution to perennial river streams. It also includes studying the major types of Himalayan hazards that have occurred in the recent past.
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    Assessment and Modelling of River Water-Sediment Pollution Load based on Spatial and Temporal Variations
    (2022) Goswami, Ankit Pratim
    This doctoral thesis attempts to understand the interrelationship between the two critical components of river ecosystem, i.e., its surface water and benthic sediments, as sediments are said to source and sink many contaminants in a river. In order to fully understand the aspects of the river ecosystem, the study has been divided into five objectives to get a better understanding of pollution load in surface water and benthic sediments, their sources and the need for monitoring and treatment. In the first part of Objective I, a survey of the probable catchment area of the river was carried out to select the sampling locations from which surface water and benthic sediment samples were collected. Sampling and analysis of surface water were carried out for 21 parameters at 18 different sites, whereas sampling and analysis of benthic sediments were carried out for 9 parameters, particularly heavy metals, at 9 different sites. The analysis of surface water samples revealed that with respect to pollution load, heavy metals present a higher risk to the consumer of surface water of Kolong river. The aim of the second part of Objective I was to use the analysed surface water samples to evaluate the drinking water quality using fuzzy logic and information entropy. Fuzzy logic based index, i.e., fuzzy water quality index (FWQI) results are more stringent than information entropy based index, i.e., entropy weighted water quality index (EWQI), as it is more sensitive to parameter variation. The aim of Objective II was to assess the benthic sediment quality or load in the river using total metal concentration and metal speciation fractions based indices. Total metal concentration based indices include geoaccumulation index (Igeo), pollution load index (PLI), enrichment factor (EF), potential ecological risk of individual metal (Eir), potential ecological risk index (PERI), and metal speciation fractions based indices, include pollution index (IPOLL), mobility factor (MF), individual (ICF) and global contamination factors (GCF), modified ecological risk index (MRI). After comparing both types of indices, it was found that the speciation-based index quantifies the risk associated with heavy metal contamination better as the indices developed using this approach gave consistent results and gel well with the variation of the
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    Global Damage Indices for RC Structures: A Numerical Response-Driven Training Approach
    (2024) Naskar, Subhadip
    Any seismic damage index model can be used to compute earthquake-induced structural damage of a building. Most researchers prefer combined damage index models (e.g., modified Park and Ang-type damage indices) due to their ability to consider the effect of both maximum and cyclic deformations on structural damage. All such combined damage models require section-level responses through nonlinear time-history analysis and cannot compute the global damage index (GDI) using global-level responses alone. Utilising the structural dynamic responses recorded by modern sensors, there is a scope for developing a new combined GDI evaluation method which uses such recorded data and avoids the requirement of numerically obtained sectional responses. On the other hand, the acceptability of the computed damage of a building utilising any damage index model through the output of a representative finite element model depends on the authenticity of the experimental data with which the finite element model is calibrated. The lateral output of any finite element model is usually calibrated with experimental results of axially loaded cantilever columns subjected to unidirectional horizontal quasi-static loading. For most of the conventional experimental setups, the true lateral behaviour of a cantilever column is altered because of the undesirable orientations of the actuators and the fixing arrangements between the actuator heads and the column tip. Therefore, the results obtained from such experiments must be rectified to generate true lateral load-deformation behaviour before being used directly for the calibration of any finite element model. Many previous research works also emphasised the need to rectify such experimental data. Therefore, a novel mechanics-based formulation to reproduce the true lateral load-deformation curve of cantilever columns from experimental data and a novel combined GDI evaluation method incorporating recorded floor-displacement responses for instrumented RC buildings during any seismic event are explored in the present study. Using the new GDI evaluation methodology, four different GDI formulae based on either displacement ductility or curvature ductility of columns are introduced to estimate the damage to 2D frames and 3D buildings. Explicit expressions of global damage coefficients available in those formulae are formulated in terms of some basic structural properties and local soil conditions. For wider applicability of the new GDI formulae, the limiting ranges of computed GDI values associated with post-earthquake restoration-based different global damage states (e.g., no damage, repairable, irreparable and collapse) are also studied
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    Study of biogeochemical and climatological impacts on spatial and seasonal variability of air-sea CO2 fluxes over the Indian Ocean
    (2023) Lekshmi, K
    The role of oceans in regulating the global climate is significantly affected by the spatial and seasonal variations in CO2 gas exchange process at the marine-atmosphere interface. The concentrations of CO2 gas in the atmosphere and ocean surface are the chief factor determining the flux direction, and are regulated by the physical, chemical and biological processes in the marine environment. These processes and their impacts vary regionally and seasonally, thereby impacting the spatial and seasonal trends in the CO2 fluxes. The Indian Ocean, with its contrasting flux trends in the western and eastern counterparts, plays a unique role in the CO2 transfer process. While the Arabian Sea acts as a net annual CO2 source, the Bay of Bengal serves as a net sink. Being an under explored oceanic region, the exact reasons behind this contrasting behavior are yet to be understood.
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    Study of Pedestrians’ Unsafe Road Crossing Behaviour at Signalised Intersection Crosswalks
    (2022) Raonia, Rahul
    The association between pedestrians' risk-taking behaviour and fatal crash frequency necessitated an understanding of pedestrians' risky road crossing behaviour at signalised intersections. Four objectives were formulated to fulfil research gaps, and data were gathered from 10 signalised intersections across Kolkata city. Under the first objective, the Impact of social and non-social factors on signal violation was studied. The second objective analysed the distracted road crossing behaviour using a questionnaire and video graphic survey. The waiting behaviour at signalised intersections was investigated using survival analysis to fulfil the third objective. Finally, pedestrian-vehicle interaction was studied using the pedestrian safety margin approach (fourth objective).
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    (A) few analytical solutions for predicting one-dimensional steady infiltration in heterogeneous soils
    (2022) Talukdar, Jagadish
    Analytical solutions are worked out for the general one-dimensional steady state infiltration equation for a heterogeneous soil column with the sink term of the equation being treated as any valid root-water uptake function along the length of an infiltrating space. Solutions are being obtained for the governing equation (Richards’s equation) considering both the Gardner as well as van-Genuchten conductivity functions. The validity of the developed solutions is being checked by comparing with the analytical works of others for a few simplified infiltration situations; also, a few numerical checks and experimental comparisons on them have also been carried out. These solutions can predict infiltration behavior through any arbitrarily inclined soil column and can also accommodate any valid spatial variations of the root-water extraction function and the soil hydraulic parameters of the infiltration equation, along the length of an infiltrating column. The study shows that infiltration on a heterogeneous Gardner or van- Genuchten soil is a highly complex process involving many variables and the spatial variations of these variables in such a soil may greatly influence the infiltration mechanics associated with it; this is true both when a root-water function is present in an infiltrating space and when it is absent. It has also come out of the study that infiltration hydraulics related to a heterogeneous Gardner or van-Genuchten soil is mostly due to the combined effect of all the players of the system and is not due to one or two infiltration variables of the system alone. As there is currently no analytical solution to either the Gardner or van-Genuchten-based infiltration equation for a heterogeneous soil with or without the sink term, it is hoped that the proposed solutions will be worthwhile additions to the collection of analytical solutions on the subject. Keywords: Analytical solution; Gardner’s conductivity function; van Genuchten’s conductivity function; Root-water extraction function; Soil heterogeneity.
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    Hydro-Chemical Evaluation of Bentonite-Fly ash Mix as Liners in Near Surface Waste Disposal Facility
    (2023) Gupt, Chandra Bhanu
    Hazardous industrial wastes are contained in engineered shallow near-surface disposal facilities or landfills. To minimize the migration of waste from landfills and protection of geoenvironment and groundwater, low permeable compacted liners are provided, which act as hydraulic and contaminant barriers. In normal practice, bentonite-sand (B-S) mixtures are recommended as liner material. Due to shortage, there is a need to explore the possibility of using alternate waste materials like fly ash (FA) as a substitute for sand (S). To ensure its application in compacted liner, the B-FA mixes should qualify hydro-chemical requirements laid out by different regulatory bodies like Environmental Protection Agency (EPA). The detailed hydro-chemical evaluation includes hydraulic conductivity determination, contaminant retention properties, adequate strength and volumetric shrinkage characteristics. Additionally, when two reactive materials (B and FA) are mixed together, it is important to ensure its compatibility over a period of time. A detailed study is needed to make sure that there are no undesirable interactions between B and FA leading to poor performance of liner. This necessitate long-term interaction studies of B-FA mixes for vital properties such as hydraulic conductivity and contaminant retention. This study investigated in detail the hydraulic conductivity of B-FA mixes under constant volume (swelling completely restricted) and free swelling conditions at time (t) varying from 0 days (immediately after compaction) to four years of interaction. Every measurement was carried out for extended duration of 90 days to ensure steady state condition.
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    Erosion Mitigation via Bio-Mediated Soil Improvement
    (2022) Dubey, Anant Aishwarya
    Existing soil erosion mitigation practices that focus on cement-based hard structures and chemical grouts have limitations in terms of their environmental impact and effectiveness. Recently bio-mediated soil improvement has been proposed by several researchers as a promising eco-friendly solution for mitigating erosion. However, the bio-mediated soil improvement techniques have their own limitations, such as bacteria transportation to the site, non-uniform distribution of bio-precipitates, and generation of ammonia as a by-product.
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    Assessment of speed variability on the horizontal curves using vehicle trajectories for geometric design consistency and safety evaluation of a two-lane rural highway passing through mountainous terrain
    (2023) Kumar, Anna Venkata Anjeneya Bharat
    Horizontal curves play a crucial role in providing a smooth and safe transition from one tangent to the successive tangent. But, the crash data corresponding to Indian highways shows that the crashes on curves went up by 46.05% on average between 2016 to 2021. In this scenario, evaluating the consistency of horizontal curves is important to improve safety. There are various consistency measures that are classified based on parameters such as operating speed, driver workload, alignment indices, side friction, and driving dynamics for assessing geometric design consistency. Among these measures, Lamm’s criteria developed based on operating speed, is widely accepted across the world and used for consistency evaluation. However, in evaluating the consistency using the Lamm’s criteria, past studies estimated operating speed (V85) using spot speed data collected at the center of the curve. Recent studies with driving simulators and GPS instrumented vehicles found that speed is varying on the curve, and collected minimum operating speed on the curve for modeling operating speed reduction models. Majority of the operating speed reduction models that were developed are meant for rural highways in plain terrain and these models are not applicable to the highways passing through mountainous terrain. Besides, none of the studies have attempted to study the design and operating speed consistency for the horizontal curves of two-lane highways passing through mountainous terrain.
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    Studies on the Use uf Thermoalkali Treated Rice Straw as Carbon Source for Oxyanions Removal by Biological Process
    (2022) Bhande, Ranjeeta
    Rice straw is one of the most abundant, renewable lignocellulosic biodegradable crop residues, but a waste material all over the world. Burning in situ, rice straw leads to air pollution. Hence, it is the uttermost requirement to sustainably utilize agricultural waste such as its use as a carbon source in biological oxyanion removal process. Oxyanions such as sulfate, nitrate, arsenate, etc. are some of the common water pollutants. Utilization of rice straw has been reported for various purposes such as bio-ethanol production, H+ production, and methane generation. Despite having great potential, its performance on oxyanion removal has not been explored so far. In the present study, the utilization of rice straw as a carbon source in biological systems for the removal of oxyanions has been studied. The target oxyanions in this study are sulfate, nitrate, and arsenic.
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    Study of the Process-form Relationships in Continuum of Braided Channel Patterns
    (2022) Pradhan, Chandan
    The braided rivers are governed by complex, unstable river networks formed due to the interaction of high flow energy and intense sediment transport. The generation of complex morphological adjustments over a braided corridor is a response to the changes in flow and sediment supply. Understanding braided river behavior and underlying concepts through field-based studies, modeling, analysis and cloud computing can be beneficial for their effective management. The present thesis provides a comprehensive understanding of the process-form relationships and associated management approaches along the continuum of braided channels.
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    Detection and Management of Virus Sources in an Aquifer under Equilibrium and Kinetic Sorption
    (2023) Gandhi, Bandaru Goutham Rajeev
    The thesis focuses on detecting virus sources in an aquifer followed by managing the sources to remediate the aquifer. The work is divided into five objectives, each of which accomplishes a different goal and is linked to remediating the aquifer. The first objective is to develop a Darcy-scaled model directly applicable to field-scaled numerical simulations. The developed model uses the Finite Volume Method (FVM), and it can handle the parameters that are spatially and temporally variable. The model is validated with MODFLOW and MT3DMS models by the end of the first objective. The second objective is to develop a pore-scaled model representing a Representative Elementary Volume (REV) in the Darcy scaled model. The pore-scaled model is developed using the traditional methods along with an addition of estimating the isotropic parameters of the aquifer as a result of the Pore Network Model (PNM). The generated PNM is optimized with the pore sizes appropriately to accomplish the desired parameters using an optimization model, Shuffled Frog Leaping Algorithm (SFLA) by the end of this objective. The flow through a single pore is solved in the third objective using the Hagen-Poiseuille law, and the velocities along each pore throat are identified. The correlation equations of a single pore are used to estimate the upscaled parameters as a function of nine pore-scaled parameters. By the end of this objective, the sensitivity of these parameters for temperature is ranked first, followed by the radius of pore throats and the virus particles, and the last is the velocity in a pore. The fourth objective focuses on the identification of virus sources in the aquifer. For this objective, a new methodology is proposed to use the information from the observation wells to reduce the search space to probable locations near the source. The methodology proposed in this objective identifies the number of sources as well as the locations of those sources with the probability of finding the locations as the initial step. Later, a modified genetic algorithm combined with a gradient-based search method is used to identify the source locations and source strengths with high accuracy. The thesis's fifth and final objective focuses on managing the virus sources by injecting hot water into the aquifer. The dependencies of the parameters on the temperature are taken from existing evidence and the result from the second and third objectives of the research. The dependencies are modeled by solving the heat transport equation and incorporating the results as time-dependent parameters using the first objective of the research. The final condition of the aquifer is obtained as a result of the fourth objective, by modeling the aquifer for virus transport. The locations, schedule, and injection discharge are obtained as a result of an optimization model solved using gradient-based and pattern search methods. Three solutions are proposed by the end of this objective, to inject the hot water at the highest virus concentration location, into the existing wells, and into the existing observation wells. All the three solutions are found to have the field applicability as the aquifer could be remediated by 97-99% by the end of the remediation period.
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    (A) study on influence of control parameters on strength, durability and microstructure of fly ash-ground granulated blast furnace slag based geopolymer mortar and concrete
    (2023) Prusty, Jnyanendra Kumar
    Ordinary Portland cement (OPC) has been extensively used as the primary binding material in the preparation of concrete. However, over last few decades, Portland cement manufacturing industry has become one of the major contributors of emission of large volume of CO2 during the manufacturing process. On the other hand, the management of industrial waste in limited landfill space creates a massive challenge for the developing countries. To mitigate these issues, since last few decades, extensive research work has been undertaken to explore new alternate and more sustainable construction materials. In this line, there is a widespread use of industrial wastes in the production of concrete. Geopolymer concrete (GPC) has gained popularity as a potential alternative of Portland cement concrete due to its better mechanical properties and environmental benefits. The major challenges associated with the geopolymer composites are the variations in the physicochemical properties of precursor materials depending upon their sources, requirement of heat curing for the development of geopolymer composites with low calcium bearing precursor materials, limited availability of efficient and systematic mix design methodologies etc. Furthermore, the limited research works on durability performance of geopolymer composites in various aggressive environment is hindering the practical application of this material.
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    Proactive Safety Assessment of Mixed Traffic on Rural Highways Using Extreme Value Theory
    (2023) Kar, Pranab
    Assessing the safety of mixed traffic on rural highways is essential since the traffic fatalities on such road facilities are disproportionately higher. Still the safety studies are very limited, especially analyzing the detailed driver behavior that leads to crashes. This study addresses the challenge of road traffic safety by utilizing naturalistic driving data collected through unmanned aerial vehicles (UAVs) and fixed video cameras on divided and undivided rural highways passing through flat and mountainous terrain, particularly in low- and middle-income countries (LMICs) like India. Surrogate safety measures (SSMs) are employed to assess safety by identifying conflicts as observable noncrash events. A multidimensional conflict indicator called anticipated collision time (ACT) is used to capture various conflict types associated with mixed traffic. The analysis reveals that sideswipe conflicts are more of a safety concern than rear end conflicts on low-volume multilane rural highways, while run-off-road (ROR) conflicts involving single vehicles are more of a safety concern on the curved segments of undivided highways in mountainous terrains. Crash risk is estimated using extreme value theory (EVT) by extrapolating crashes from severe traffic conflicts. Powered two-wheelers (PTWs) exhibit significantly higher sideswipe crash risk on multilane highways, emphasizing their vulnerability in mixed traffic conditions. Heavy commercial vehicles (HCVs) experience a significant ROR crash risk on rural curved segments of undivided mountainous highways. Microscopic variables such as evasive actions are incorporated to enhance crash risk estimates, showing the influence of braking and steering rates on sideswipe crash risk. Various road geometry factors are incorporated to improve the ROR crash risk estimates. The findings highlight the need for appropriate infrastructure design, considering the specific characteristics of different conflict types and vehicle types, to improve road safety.
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    (A) Frequency Domain based Inverse Ground Response Analysis Framework for the Determination of Dynamic Soil Properties
    (2023) Mondal, Joy Kumar
    Effect of local soil in amplifying bedrock motion during earthquakes (EQs) is an important phenomenon, and is observed globally. As a result, the bedrock motion at times increases manifold while reaching the surface. Such amplification in ground motions due to local soil is termed as local site effect (LSE), and can numerically be quantified by performing ground response analysis (GRA). Understanding the effect of local soil requires information about subsoil type as well as shear strain dependent behaviour of each subsoil layer (known as dynamic soil properties curves or DSPCs). Literature suggests that DSPCs of local soil are not readily available at regional level. Due to this reason, while attempting to estimate LSE, majority of site-specific studies consider DSPCs developed for other region's soils. DSPCs, though can be determined using existing inverse GRA methodologies, critical review done in this work highlighted that most of the frequency domain studies target to determine change in shear modulus (G) with shear strain (γ) but no to very limited studies target to determine damping ratio (β) variation with γ (or β curve). Additionally, these methodologies are limited to finding out soil properties for the surficial layer only. During an EQ excitation however, each of such soil layers will behave distinctively
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    Hydrological Modelling of River Basin and Strategic Management of Watershed under Different Anthropogenic and Climate Change Scenarios: A Case Study of Genale Catchment, Ethiopia
    (2022) Negewo, Tufa Feyissa
    It is important to estimate the quantity and quality of water resources in terms of spatial and temporal variability to utilize it sustainably. Change in future climate conditions affects the availability of water resources by modifying the magnitude of precipitation, groundwater recharge, surface runoff, actual evapotranspiration, lateral flow, water yield, the river flows, and provoke water stress in the downstream. Local government authority around the globe is also emphasizing water resources project exploration, design, planning, and management aspect within the river basin.
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    Utilisation of Basic Oxygen Funace Steel Industry Slag in Open Graded Asphalit Friction Course Mises
    (2022) Pathak, Santanu
    Open graded asphalt friction course (OGAFC) is a special purpose bituminous mix applied as a surface course for improved skid resistance and road safety especially under wet weather conditions. These mixes are characterised by high air voids content, generally greater than 18% of the mix volume, which are achieved through a uniform aggregate gradation that predominantly comprises of coarse aggregates. For adequate load transfer in OGAFC mixes through proper stone-on-stone contact these mixes demand comparatively good quality road. The increasing cost and the shortage of good quality natural aggregates, have compelled researchers and practitioners to explore alternate aggregate materials to attain sustainability in road construction. Steel slag is an industrial bylco-product obtained during the conversion of pig iron or steel scrap to industrial quality steel. Steel slag is classified as ether basic oxygen furnace (BOF) slag or electric-arc fumace (EAF) slag, depending on the fumace/process employed in its conversion.
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    Investigation of engineering properties and vegetation performance of biochar-amended soil for the application in the bioengineered structures
    (2022) Hussain, Rojimul
    Soil bioengineered structures are comprised of soil for stability and vegetation for protection. These structures are commonly adopted because of their multiple beneficial impacts. The stability and performance of these structures depend on the soil engineering properties and vegetation performance. Further, the vegetation performance i.e., the vegetation growth and health status are interrelated to the soil engineering properties. The vegetation in these structures provides additional stability and protection from erosion and failure. The vegetation roots act as soil reinforcement by anchoring or bridging the soil particles together through mobilization of its tensile strength. The root water uptake by the roots induces suction in soil that in turn increases soil shear strength or stability in terms of apparent cohesion. Further, the above ground mass of vegetation protects the soil surface from erosion along with the aesthetic view. Therefore, suitable growth and health status of vegetation are utmost important for the effective functioning of bioengineered structures. Many a times soil does not provide suitable condition for the growth and health status of vegetation and therefore several amendments have been adopted for improving the vegetation performance. Among these amendments, biochar has been regarded as more suitable soil amendment due to their stable structure i.e., microbial non-degradable and organic nature. Biochar is a carbon-rich material obtained after pyrolysis of biomass under oxygen deficit condition. The conversion of biomass into biochar is also the sustainable way of managing wastes, mitigating climate change and producing energy. Biochar as soil amendment is often used for soil carbon sequestration, improving the soil fertility as well as crop growth and yield, and removing the organic and inorganic pollutants from soil. Application of biochar as soil amendment majorly focused on loose agricultural soil. Soil in bioengineered structures is different from the agricultural soil i.e., often compacted for achieving stability and subjected to a prolong drying due to the irregular irrigation pattern. Therefore, the engineering properties of biochar-amended soil (BAS) and the vegetation performance in BAS need to be investigated under compacted state for ensuring effective stability and performance of bioengineered structures. In the present thesis work, the engineering properties i.e., the hydro-mechanical and physicochemical properties of biochar-amended compacted soil and the vegetation (grass species) growth and health status in biochar-amended compacted soil have been investigated for potential application in bioengineered structures. The results revealed that the amendment of biochar improved the soil engineering properties by increasing the soil pH, CEC, water retention capacity, shear strength and load bearing capacity, and decreasing the dry density, infiltration rate, saturated hydraulic conductivity, unsaturated hydraulic conductivity and desiccation crack potential. Further, the biochar amendment found to be improved the vegetation performance by increasing the vegetation (roots and shoot mass) growth, delaying the wilting (higher permanent wilting point), decreasing the stomatal conductance (pathogen resistance or good health) and allowing complete photosynthetic activity at relatively large suction. The amendment of different types biochar found to be exhibited variable responses on the soil engineering properties and vegetation performance. Adversely, the undrained shear strength or UCS of the soil was found to be decreased after biochar amendment which needs to be further investigated. However, the magnitude of UCS obtained for 5% (w/w) biochar amendment rate was found to be higher than the minimum (200 kPa) required strength for most of the bioengineered structures and suggested by the united state environmental protection agency (USEPA). Based on the present thesis work, it is suggested to use 5% BAS in bioengineered structures; however, considering field trials before application would add more reliability.
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    (A) Time Domain Approach for Bridge Fatigue Considering the Effect of Multiple Vehicles at Random Passing Rate
    (2022) Pillai, Anjaly J
    Bridges are lifeline structures in transportation network. Smooth flow of traffic through bridges is important consideration for socio-economic development of any regions. The bridges are generally designed with high factor of safety to cater for uncertainty in live load and material properties. With time, the structures may show various forms of degradation. This is mostly common where traffic growth is unexpectedly high and the structures are exposed to aggressive environment, which necessitates a more elaborate approach to estimate fatigue life in design phase itself. Burden of in-situ monitoring of crack growth may thus be reduced.
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    Seismic performance evaluation of RBS-CFT connections with bidirectional bolts under cyclic loads
    (2022) Paul, Subhra
    This thesis presents experimental investigation on evaluation of performance of a new type of steel reduced beam section (RBS), designated as V-cut, and on its role in improving overall safety of RBS-CFT connections subjected to cyclic load. Detailed design steps adopted for design of the V-cut RBS with lower depth of cut, as compared to that in the conventional radius cut RBS, are reported in this paper. Behavior of four types of steel RBS and concrete filled tube (CFT) connections with bidirectional bolts were examined. An experimental study was performed to compare the performance of V-cut RBS with that of the other conventional radius cut RBS under cyclic loading. It exhibited improved hysteretic behavior, and the new RBS-CFT connection is found to be semi-rigid in nature. Test results show that the energy dissipation in the composite steel connections with V-cut RBS is higher than that with radius cut RBS. The application of V-cut steel flange beam effectively enhanced ductility and reduced the residual torsional deformation. It reached a rotational capacity of 0.04 radians without any damage in the joint panel region, and thereby meets the seismic provisions of the AISC as a special composite moment-resisting frame. Detailed and simplified nonlinear finite element analysis of RBS-CFT connections with bidirectional bolts was performed using the general-purpose software ABAQUS and OpenSees respectively. The failure patterns of the connections were obtained by the ABAQUS software. Simplified model was proposed in OpenSees to regenerate the hysteresis loops as obtained from the experimental study. Finally, seismic vulnerability assessment has been done by developing experimental fragility curves.