Nagavinothini Ravichandran
@chula.ac.th
Senior Postdoctoral Researcher, Center of Excellence in Interdisciplinary Research for Sustainable Development, Faculty of Engineering
Chulalongkorn University
I am a researcher currently working on earthquake engineering and structural control.
My research interests include dynamic analysis of structures, analysis of structures under extreme events, floating structures, and computer-aided analysis of structures.
EDUCATION
Ph.D. Ocean Engineering (2019), IIT Madras, Chennai, India
Specialization: Offshore structures
M.E. Structrual Engineering (2014), ACCET, Karaikudi, India
First rank holder and Gold medalist
B.E. Civil Engineering (2012), SRIT, Coimbatore, India
University first rank holder and Gold medalist
RESEARCH, TEACHING, or OTHER INTERESTS
Civil and Structural Engineering, Ocean Engineering, Renewable Energy, Sustainability and the Environment, Multidisciplinary
FUTURE PROJECTS
Design of novel floating structures for photovoltaic systems
Applications Invited
Numerical modelling of masonry structures
Applications Invited
Dynamic response analysis of structures under extreme loads
Applications Invited
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Nagavinothini Ravichandran, Daniele Losanno, Maria Rosaria Pecce, and Fulvio Parisi
Springer Science and Business Media LLC
AbstractThe present-day road traffic with the persistent change in the type and volume of vehicles needs to be specifically investigated for effective safety management of aging highway infrastructures. Actual traffic data can be implemented in refined procedures for stochastic simulation of road infrastructure performance, structural health monitoring (SHM), definition of weight limits on highways, and traffic-informed structural safety checks. While weigh-in-motion (WIM) systems had been widely used in many countries, their installation on Italian highways was mostly discussed and carried out only after the catastrophic collapse of the Polcevera bridge in 2018. This study presents a statistical data analysis, probabilistic models, and a simulation procedure for highway traffic, based on measurements of two WIM systems located along European route E45 close to Naples, Italy. Different limitations to maximum gross vehicle weight (GVW) were enforced at the locations of the two WIM systems, according to the Italian road code and the Italian guidelines for risk classification, safety assessment and monitoring of existing bridges, respectively. WIM data sets were filtered to exclude erroneous traffic data and vehicle classes defined according to the number of axles and axle distance were statistically characterised, allowing the derivation of probabilistic models for all traffic parameters of interest. A simulation methodology to generate random traffic load from the WIM data is also presented for its possible use in probabilistic performance assessment and traffic informed SHM of road infrastructures such as bridges.
Nagavinothini Ravichandran and Butsawan Bidorn
MDPI AG
Freak waves are characterized by extreme wave height, irregular wave shape, high peak energy, short duration, and formidable destructive potential, posing a significant threat to offshore structures. Therefore, analyzing dynamic responses exhibited by advanced offshore platforms such as the offshore triceratops under the influence of freak waves holds paramount importance. However, the response analysis of offshore triceratops under freak waves has not been explored so far in the literature. Hence, the present study aims to investigate the dynamics of offshore triceratops intended for ultradeep waters under the impact of freak waves. Initially, the dual superposition model was utilized to generate the freak waves, and the numerical model of the platform was developed using ANSYS AQWA. Subsequently, the dynamic response characteristics of offshore triceratops under the influence of freak waves were analyzed in the time domain. The results demonstrate the effects of freak waves on the surge, heave, and pitch responses of the deck and buoyant legs were substantial, leading to a significant increase in maximum responses and variations in mean shift and standard deviations. The innovative insights derived from this study can serve as a benchmark for validating the effective performance and design of offshore triceratops.
Balamurugan Panneerselvam, Nagavinothini Ravichandran, Umesh Chandra Dumka, Maciej Thomas, Warit Charoenlerkthawin, and Butsawan Bidorn
Elsevier BV
Balamurugan Paneerselvam, Nagavinothini Ravichandran, Peiyue Li, Maciej Thomas, Warit Charoenlerkthawin, and Butsawan Bidorn
Elsevier BV
Nagavinothini Ravichandran, Balamurugan Paneerselvam, and Nagananthini Ravichandran
Oxford University Press (OUP)
Abstract Floating photovoltaic systems (FPVs) are one of the emerging renewable-energy technologies suitable for implementation in land-scarce areas around the world. The installation of FPVs in water bodies in highly populated countries such as India will improve renewable-energy production with added advantages in terms of efficiency, water savings and reduced carbon emissions. In this context, the present study aims to identify suitable reservoirs for solar energy production using FPV technology in Tamil Nadu, India using geographic information system techniques. A total of 118 reservoirs located in the study area were considered. The results have shown that the implementation of FPV systems will significantly improve the production of renewable energy. The most suitable reservoirs with hydroelectric power plants for hybrid FPV implementation and their potential to reduce water evaporation and carbon emissions are presented. The results reveal that hybrid systems will generate 1542.53 GWh of power annually and also save 36.32 × 106 m3 of water every year. The results of this investigation will aid in fulfilling sustainable energy production in India, and the methodology presented may be useful for the analysis and prioritization of reservoirs for the implementation of FPV all over the world.
Balamurugan Panneerselvam, Nagavinothini Ravichandran, Shunmuga Priya Kaliyappan, Shankar Karuppannan, and Butsawan Bidorn
MDPI AG
The continuous intake of contaminated drinking water causes serious issues for human health. In order to estimate the suitability of groundwater for drinking and irrigation, and also conduct human risk assessments of various groups of people, a total of 43 sample locations in the semi-arid southern part of India were selected based on population density, and we collected and analyzed groundwater from the locations for major anions and cations. The present study’s novelty is integrating hydrochemical analysis with the entropy water quality index (EWQI), nitrate pollution index (NPI) and human health risk assessment. The results of the EWQI revealed that 44.19% of the sample locations need to be treated before consumption. About 37.20% of the study region has a high concentration of nitrate in the groundwater. NPI revealed that 41.86% of the samples had moderate or significant pollution levels. The non-carcinogenic risk evaluation showed that 6–12-year-old children are at a higher risk than teenagers, adults and elderly people in the study area. The natural sources of nitrate and other contamination of groundwater are rock–water interaction, weathering of rock, dissolution of carbonate minerals and evaporation processes, and the anthropogenic sources are the decomposition of organic substances in dumping yards, uncovered septic tanks and human and animal waste. The results suggest taking mitigation measures to reduce the contamination and improve the sustainable planning of groundwater management.
Daniele Losanno, Nagavinothini Ravichandran, and Fulvio Parisi
Wiley
Unreinforced masonry (URM) buildings are highly vulnerable to seismic ground motion, calling for quantitative risk assessment and mitigation programmes in different earthquake‐prone countries to reduce future losses. Despite the effectiveness of base isolation technology in reducing seismic response of buildings, the high costs of conventional isolators prevent their application to low‐cost housing in developing countries. Fiber‐reinforced elastomeric isolators (FREIs) have been recently developed as low‐cost isolators suitable for application to URM buildings. The structural performance assessment of base isolated URM buildings using FREIs can be a sustainable solution for a large‐scale mitigation of seismic risk. In this context, the present study presents the seismic fragility analysis of both fixed‐base and base‐isolated URM buildings. Five URM building archetypes were considered to account for variation in geometry and building configuration. A number of static pushover analyses and nonlinear time history analyses were carried out to assess the capacity and demand of the selected buildings, respectively, while considering the uncertainties associated with material properties, capacity model, damage state and earthquake ground motion. The fragility curves were developed for both fixed‐base and base‐isolated configurations of the different archetypes. The results show that the probability of slight to moderate damage to fixed‐base URM buildings is significantly higher than their base‐isolated counterparts, demonstrating that FREIs significantly improve their seismic performance. These outcomes address further research in promoting the development of FREIs to reduce the vulnerability of URM buildings in developing countries.
Balamurugan Panneerselvam, Kirubakaran Muniraj, Chaitanya Pande, and Nagavinothini Ravichandran
Informa UK Limited
Suresh Sundaramurthy, Shashi Bala, Anil Kumar Sharma, Jyoti Verma, Sasan Zahmatkesh, S. Arisutha, Sarika Verma, Mika Sillanpaa, Nagavinothini Ravichandran, and Balamurugan Panneerselvam
MDPI AG
Paver blocks are manufactured from zero-slump plain concrete, which is small element used for outdoor applications and flexible road surfaces. IS:15658 (2006) permits the use of 33- grade ordinary Portland cement (OPC) as the minimum for manufacturing paver blocks, but the usage of this type of cement is restricted in India nowadays. In this context, we have studied OPC 43-grade cement replaced by 30% Class F-grade fly ash and the addition of 0.0% and 0.5% polypropylene fibre (PPF) to evaluate the suitability of paver blocks in terms of the climatic conditions, movement of vehicles and road surfaces in India. The synergistic effect of the mechanical properties of paver blocks revealed that a 30% replacement of OPC with fly ash and 0.3% PPF is more suitable for the manufacturing of paver blocks. The obtained results from the reference mixes indicated that the mechanical properties of paver blocks have increased with respect to the age of the blocks. The present study is important for paver block manufacturers as it fulfils the mix design, strength and durability requirements for Indian roads associated with the utilization of waste materials such as fly ash. Additionally, the study will help the national economy increase by 20% in the future, along with the sustainability of virgin materials.
Balamurugan Panneerselvam, Kirubakaran Muniraj, Chaitanya Pande, Nagavinothini Ravichandran, Maciej Thomas, and Shankar Karuppannan
Springer Science and Business Media LLC
The primary goal of this study is to evaluate the groundwater quality and conduct a non-carcinogenic risk assessment of nitrate contamination in an industrialized and high-density region of South India. A total of 40 sampling sites were identified in and around the industrial area, and samples were collected during the pre-monsoon and post-monsoon seasons. Piper and Gibbs’ diagram shows that rock-water interaction, lithological characteristics and ion-exchange processes are the primary factors determining groundwater quality. The novel entropy water quality index (EWQI) indicated that 32 and 37.5% of the water in the study area were unsuitable for drinking purposes during both the pre-monsoon and post-monsoon seasons, respectively. Due to landfill leachate and modern agricultural activity, the nitrate concentration in groundwater post-monsoon had increased by 17.11%. The nitrate pollution index (NPI) value of groundwater exceeded the contaminated level by 22.77%. The non-carcinogenic human health risk assessment revealed that 35 and 40% of adult males, 37.5 and 52.5% of adult females and 42.5 and 55% of children during the pre-monsoon and post-monsoon periods were exposed to an increased concentration of nitrate in groundwater. The non-carcinogenic risk level to the exposed population in the study region descends in the following order: children > > females > males. The study suggests that low body weight in children is a direct result of consumption of low-quality water and that adult men and women suffer less severe consequences.
Nagananthini Ravichandran, Nagavinothini Ravichandran, and Balamurugan Panneerselvam
Elsevier BV
Chaitanya B. Pande, Balamurugan Panneerselvam, Kirubakran Muniraj, and Nagavinothini Ravichandran
Springer International Publishing
Kirubakaran Muniraj, Balamurugan Panneerselvam, Nagavinothini Ravichandran, and Chaitanya Baliram Pande
Springer International Publishing
N. Ravichandran, N. Ravichandran, and B. Panneerselvam
Springer Science and Business Media LLC
AbstractFloating photovoltaic system for reservoirs is a recent innovative technology that is highly advantageous in reducing evaporation while generating solar power. In addition, the integration of floating photovoltaic systems with the existing hydroelectric power plants will increase renewable power production. The present study aims to assess the electrical performance of floating photovoltaic systems in major reservoirs with existing hydroelectric power plants in India. The reservoirs with large water surface area were selected for the study, and a model floating photovoltaic system with a 5-MW capacity was designed for the selected reservoirs. The numerical analysis showed that installing floating photovoltaic systems will result in an annual energy yield of 160 GWh. Further, the systems also save 1.40 million cubic meters of water per day and also help in generating additional energy of 514.80 MWh/day from the saved water through its integration with hydroelectric power plants. A single-axis tracking mechanism to the floating photovoltaic systems will increase the annual energy generation by 11%. The detailed cost analysis and carbon emission analysis were also carried out. The results indicate that the tracking mechanisms increase the total installation cost of the systems. The annual carbon emission reduction from the floating photovoltaic systems accounts for about 3.30 million tons of CO2. The obtained results highlight the suitability of this innovative technology for installation in Indian reservoirs and its effectiveness in reducing evaporation and carbon emission. Graphic abstract
Nagananthini Ravichandran, Nagavinothini Ravichandran, and Balamurugan Panneerselvam
Springer Singapore
Daniele Losanno, Nagavinothini Ravichandran, and Fulvio Parisi
Elsevier BV
K. Shunmugapriya, Balamurugan Panneerselvam, Kirubakaran Muniraj, Nagavinothini Ravichandran, P. Prasath, Maciej Thomas, and Karunanidhi Duraisamy
Elsevier BV
Deterioration of water and soil quality, poor infrastructure facilities and improper maintenance are the major factors that govern aquaculture growth and production in major part of India. In the present study aims to identify the suitable land for aquaculture growth and suggest the sustainable practice to improvise the growth of aquaculture in study region. With use of analytical hierarchy process (AHP) the various significant parameters such as geology, pH, salinity, soil media, slope, geomorphology, land use land cover, distance to water, settlement and road networks were analyzed and based on these characteristics, thematic maps were prepared. The results are revealed that, that 882.13 km2 area was most suitable, 1264.88 km2 area was suitable and 14.00 km2 area was unsuitable for aquaculture in the study region. The study results will helpful to decision makers and to make a design plan for aquaculture growth in the study region.
Balamurugan Panneerselvam, Kirubakaran Muniraj, Maciej Thomas, Nagavinothini Ravichandran, and Butsawan Bidorn
Elsevier BV
Quality of water for the purposes of irrigation is a serious threat to the sustainable development of the agriculture sector. The main objective of this study is to evaluate the suitability of groundwater for irrigation purposes using various irrigation indices such as: Sodium Absorption Ratio (SAR), Residual Sodium Carbonate (RSC), Percentage Sodium (%Na), Magnesium Hazards (MH), Permeability Index (PI), Potential Salinity (PS), Residual Sodium Bicarbonate (RBSC), Kelly's Ratio (KR), Synthetic Harmful Coefficient (K), and Exchangeable Sodium Percentage (ESP). A total of 30 samples were collected from the bore well of agricultural farmland and analysed for cations and anions. MH reveal that 53.33 % of samples exceed the permissible level. PS shows that 43.33 % of samples are marginally affected and 33.33 % of samples are unsuitable for use in irrigation. About 76 % of the groundwater samples were suitable for irrigation and the remainder require treatment before use. Automatic Linear Modelling (ALM) is used to predict the major influence parameter for MH and PS are RBSC, RSC and K value of groundwater. ALM shows that excess magnesium concentration and salinity are the primary factors that affect the suitability of groundwater for irrigation use. This integrated technique showed that water from approximately 25 % of the sample locations would require treatment before use. This study will improve the pattern of irrigation, identify sources of contamination and highlight the importance of organic fertilizers to develop and enhance the sustainable practices in the study region.
Nagavinothini Ravichandran, Daniele Losanno, and Fulvio Parisi
Springer Science and Business Media LLC
AbstractAll around the world, non-engineered masonry constructions (NECs) typically have high vulnerability to seismic ground motion, resulting in heavy damage and severe casualties after earthquakes. Even though a number of computational strategies have been developed for seismic analysis of unreinforced masonry structures, a few studies have focussed on NECs located in developing countries. In this paper, different modelling options for finite element analysis of non-engineered masonry buildings are investigated. The goal of the study was to identify the modelling option with the best trade-off between computational burden and accuracy of results, in view of seismic risk assessment of NECs at regional scale. Based on the experimental behaviour of a single-storey structure representative of Indian non-engineered masonry buildings, the output of seismic response analysis of refined 3D models in ANSYS was compared to that of a simplified model based on 2D, nonlinear, layered shell elements in SAP2000. The numerical-experimental comparison was carried out under incremental static lateral loading, whereas nonlinear time history analysis was performed to investigate the dynamic performance of the case-study structure. Analysis results show that the simplified model can be a computationally efficient modelling option for both nonlinear static and dynamic analyses, particularly in case of force-based approaches for design and assessment of base isolation systems aimed at the large-scale seismic vulnerability mitigation of NECs.
Nagananthini Ravichandran, Nagavinothini Ravichandran, and Balamurugan Panneerselvam
Oxford University Press (OUP)
Abstract Floating photovoltaic (FPV) systems are one of the globally emerging technologies of renewable energy production that tend to balance the water–energy demand by effectively saving the evaporated water from reservoirs while generating electrical power. This study presents the performance analysis of a model FPV plant in an Indian reservoir. The Mettur dam reservoir located in Tamil Nadu, India with a hydroelectric power plant of 150-MW capacity is considered as a test case. The preliminary design of the FPV plant is proposed based on a detailed study of the key design elements and their suitability for Indian reservoirs. The proposed plant is numerically analysed for various tilt angles, mounting systems and tracking mechanisms in order to assess its potential power generation. A flat-mount system in landscape orientation was found to exhibit a high performance ratio. Further, a fixed-tilt FPV system with a panel slope of 10° and an FPV system with single-axis tracking were found to be suitable for the Mettur reservoir. Further, cost analysis of the FPV system is also presented along with the carbon-footprint estimation to establish the economic and environmental benefits of the system. The results show that the total potential CO2 saving by a FPV system with tracking is 135 918.87 t CO2 and it is 12.5% higher than that of a fixed-mount FPV system.
Balamurugan Panneerselvam, Kirubakaran Muniraj, Maciej Thomas, and Nagavinothini Ravichandran
Springer International Publishing
Daniele Losanno, Nagavinothini Ravichandran, Fulvio Parisi, Andrea Calabrese, and Giorgio Serino
Elsevier BV
Abstract Unreinforced masonry (URM) buildings are one of the most common type of constructions in developing countries, due to their reduced cost and ease of fabrication. However, the traditional non-engineered nature of these buildings combined with the poor mechanical performance of their structural materials pose a major threat to their earthquake performance, often resulting in heavy damage and losses. This study investigates the possibility of improving the response of typical URM buildings in developing countries, using a novel low-cost fibre reinforced elastomeric isolators (FREIs) developed with recycled rubber (RR). Detailed three-dimensional finite element analyses were carried out on the fixed-base (FB) and base-isolated (BI) configurations of the prototype building subjected to a set of strong recorded ground motions, considering both the design basis earthquake (DBE) and maximum considered earthquake (MCE). The numerical model of the URM building was developed using non-linear shell elements and bilinear springs that respectively simulated the hysteretic behavior of masonry walls and RR-FREIs. Numerical results show a significant reduction in both the accelerations and inter-story drifts of the BI configuration when compared to the response of the FB building. The global elastic response and corresponding enhanced seismic performance of the BI building under DBE confirm the effectiveness of the proposed base isolation system in protecting non-engineered URM buildings from seismic events with medium-to-high intensity.
Nicolò Vaiana, Daniele Losanno, and Nagavinothini Ravichandran
Elsevier BV
Abstract This paper presents a novel family of multiple springs models capable of reproducing the nonlinear response typical of mechanical systems and materials having a biaxial kinematic rate-independent hysteretic behavior. In such a formulation, the generalized force vector, representing the output variable, is computed by summing the contribution of n springs, respectively made up of a nonlinear elastic spring in parallel with a rate-independent hysteretic one. In particular, the generalized force of each spring is computed as a function of the related generalized displacement and history variable. Two isotropic biaxial hysteretic models are derived from the proposed general formulation: the Multiple Springs Bilinear Model and the Multiple Springs Exponential Model. The former is an algebraic model that is illustrated to clearly explain the meaning of the parameters and variables adopted in the formulation. Conversely, the latter is a transcendental model that is presented not only to demonstrate the potentiality of the family in terms of accuracy and computational efficiency, but also to show the possibility of developing models that can reproduce different types of biaxial hysteretic behavior with few parameters having a clear mechanical significance. Such a sophisticated model is validated through numerical and experimental tests.
Nagavinothini Ravichandran
Institute of Structural Analysis and Antiseismic Research National Technical University of Athens
In common practice, uncoupled hysteretic models, that is, models that do not consider the bi-axial interaction between the restoring forces along two generic orthogonal transverse directions, are typically employed to perform nonlinear time history analyses of base isolated structures. However, such models do not suitably reproduce the exact response of the structure when the system is subjected to external excitation in two orthogonal directions. Thus, the selection of suitable phenomenological model and the time integration method is important while carrying out nonlinear time history analysis (NLTHA) of base isolated structures. In the present study, a detailed investigation is carried out to assess the effectiveness of two hysteretic models to reproduce the hysteretic behaviour of the elastomeric bearings. A three-dimensional base-isolated reinforced concrete building is analysed under earthquake excitations, by employing a novel biaxial phenomenological model denominated Multiple Springs Exponential Model (MSEM) and Biaxial Bouc-Wen model (BBWM). Numerical accuracy and the computational efficiency of these methods are assessed through NLTHA. The results show that the novel method is advantageous and computationally efficient in comparison with BBWM.