Faculty Publications
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Item The limit of limits(School of Engineering and Technology, 2006) Babu Narayan, K.S.B.Throughout the history structural engineering has wrestled with the forces of nature and has accomplished the inspiring, daring and amazing feats of innovating structures of gigantic proportions. The tallest building on earth has crossed the 500m barrier and heights exceeding 800m are being ambitiously contemplated. Mind boggling spans for bridges are being suggested and possibilities are being investigated. At this most-happening juncture of time, this paper envisages to explore, with simple and familiar concepts, the limits of possibilities and the hurdles to be cleared to extend the limits. © 2006 by School of Engineering and Technology, Asian Institute of Technology.Item Application of Proper Orthogonal Decomposition in Concrete Performance Appraisal(Springer Science and Business Media Deutschland GmbH, 2021) Manoj, A.; Babu Narayan, K.S.B.Mould ability of concrete has made it the most versatile and popular material of construction. Workability, strength and durability of concrete are very important characteristics that depend on a large number of variables like cement and aggregate type, mix proportioning, method of mixing, conveying, placing and curing and environmental conditions of exposure like temperature, humidity, wind velocity and insolation. The degrees to which workability, strength and durability characteristics vary, and also interplay and conflicts make decision on consideration of independent variables that influence concrete performance, make the job of analysts very complex. Proper Orthogonal Decomposition (POD) is a tool that has great usage potential in reorganizing and rationalizing vast data to understand dependence, interdependence and independence of variables that affect the concrete characteristics. This paper presents the utility of Proper Orthogonal Decomposition in concrete performance appraisal. © 2021, Springer Nature Singapore Pte Ltd.Item Assessment of Pushover Response Parameters Using Response Surface Methodology(Springer Science and Business Media Deutschland GmbH, 2021) Panandikar, N.; Babu Narayan, K.S.B.Pushover analysis is a non-linear static method used for the seismic assessment of structures. The simplicity, efficiency in modelling and less computational time make this method popular. Lot of researchers has worked on conventional pushover analysis and after knowing deficiencies of the method have made efforts to improve it. From the literature, it is evident that actual experimental test results carried out so as to verify the analytically obtained pushover results are hardly available. Stress–strain models adopted for modelling of concrete and reinforcement greatly influences both the ultimate load and ultimate displacement for the structure under pushover loads. This paper focuses on assessment of pushover response parameters using response surface methodology (RSM). A three-storied RCC framed structure is tested and the experimental pushover results are available. Uncertain parameters considered include the concrete strength, steel strength, reinforcement cover and hinge location, which are randomly generated by performing stochastic analysis and their effect on responses, which include base shear and displacement is studied. Using Monte Carlo simulation in Sap-2000 design matrix is generated. Modelling and analysis of response parameters are carried out using RSM so as to obtain the characteristics of the pushover curve. The effect of material strength variation, hinge locations and hinge lengths, geometric modelling have been studied, incorporating confined model for concrete. The coefficients and equations that can be used to predict the responses are carried out by performing multiple regression analysis. The validation results demonstrated that the confined model is better than the unconfined. © 2021, Springer Nature Singapore Pte Ltd.Item The Need for Unsaturated Soil Mechanics: A Brief Review(Springer Science and Business Media Deutschland GmbH, 2021) Ujwala Shenoy, K.; Babu Narayan, K.S.B.; Sunil, B.M.Soils exhibit seasonal saturation and desiccation, often resulting in varying degrees of moisture content. In practice, soil is seldom fully saturated. When it is completely dry or wet, it behaves as a two-phase system. Otherwise, the moisture content within the interstices of soil vary, leading to partially saturated conditions. Unsaturated soil condition has significant influence on soil behaviour. This paper presents a brief review of the emergence of unsaturated soil mechanics and its applications. © 2021, Springer Nature Singapore Pte Ltd.Item Stability Analysis of Lift Shaft Tower with Guys for Wind Load(Springer Science and Business Media Deutschland GmbH, 2023) Shreekiran; Babu Narayan, K.S.B.Petroleum refinery produces coke and is one product that is enjoying huge clientele. Access to various levels of the coke-drum unit is provided by lifts and stairway. The steel tower accommodating the lift shaft and stairway is connected to the coke-drum structure proper at discrete locations. Vibration due to coke-drum operations is being transmitted to the lift/stairway shaft because of the connection, which is of concern for long-term strength, stability, and serviceability requirements. Analysis has revealed, and detachment of the shaft from coke-drum proper makes it inadequate for lateral loads. This paper presents the investigation on the possibility of employing guys to make it resistant against wind load. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Shape optimization of steel reinforced concrete beams(Techno Press, 2007) Babu Narayan, K.S.B.; Venkataramana, K.Steel reinforced concrete is perhaps the most versatile and widely used construction material. The versatility is attributed to mouldability of concrete to any conceivable shape. The inherent property of cracking of concrete is the reason for its low tensile strength and hence the design approach of RCC sections in flexure adopts the cracked section theory where in concrete in tension zone is ignored. Means, modes and methods of exploitation of concrete strength by conceiving shapes other than rectangular whereby ineffective concrete in tension zone is reduced and incorporated in compression zone where it is effective needs consideration. Shape optimization of beams is attempted in this analytical investigation employing Sequential Unconstrained Minimization Technique (SUMT). The results clearly show that trapezoidal beams happen to be less costlier than their rectangular counterparts, their usage needs serious reconsideration by the designers.Item Load-moment interaction envelopes for design of tall stacks - A limit state approach(2007) Babu Narayan, K.S.B.; Yaragal, S.C.Chimneys act as an indirect and effective means of air pollution control and have been popular from time immemorial. Environmental protection agencies have been forced to frame, implement and monitor stringent pollution control policies. With control regulations becoming more stringent, chimneys of heights over 400 m are being erected and used. Design of reinforced concrete tall stacks for load and wind induced moments by trial and error technique involves rigorous computational efforts. Availability of interaction envelopes help reduce computational time. This paper presents such design aids for tall stacks.Item Feasibility of gurpur river at Malavoor as a sink for Bajpe town domestic waste disposal - A case study(2009) Babu Narayan, K.S.B.; Kumar, J.P.; Yaragal, S.C.; Shrihari, S.Mangalore is one of the fast growing cities in Karnataka with improved infrastructure taking place in recent days. In view of rapid development in and around Mangalore city, the sub urban or rural areas around the city have started developing at a rapid rate. One such place is Bajpe where the town is growing very fast due to the expansion of activity of Bajpe Airport and upcoming SEZ projects. An attempt has been made to find out the load on River Gurupur, if the Bajpe town domestic waste is assumed to be disposed to River Gurupur at Malavoor bridge point downstream without any treatment. Experiments were conducted to find the parameters used to find out the dissolved oxygen (DO) consumption and replenishment in teh river body using BOD-DO river quality model developed by Streeter-Phelps (1925). Model formulation, analysis and the results obtained are discussed in the paper. Copyright © Enviromedia.Item The utility of proper orthogonal decomposition for dimensionality reduction in understanding behavior of concrete(Techno-Press, 2021) Manoj, A.; Babu Narayan, K.S.B.Properties of wet and set concrete are influenced by a wide range of variables. With new formulations being tried and adopted, understanding workability, strength and durability characteristics of these formulations is of utmost importance. From among the wide range of variables that affect properties of concrete, identification of the most vital, interplay between variables, quantification of influence, for judicious manipulation of mix proportioning, placement, compaction and curing, to get the desired and targeted end results can vastly be improved by employing the state of the art data handling tools. Group method of data handling (GMDH), a set of mathematical algorithms, is of great usage potential in multi-variable data modeling, optimization and pattern recognition. Proper Orthogonal Decomposition (POD) a subset of GMDH, a technique for systematic dimensionality reduction and pattern recognition, is of great importance in studying complex datasets. This paper presents the need for adoption of GMDH techniques in concrete technology with an account of trends in this direction and also provides an illustration of POD’s utility as a valid decision-making tool in dimensionality reduction and projection of behavior of concrete subjected to elevated temperature. © 2021 Techno-Press, Ltd.Item Utilization of Discrete Element Method in Multi-phase Soil Modeling for Soil Slope Stability Analysis(Institute for Ionics, 2023) Ujwala Shenoy, K.U.; Babu Narayan, K.S.B.; Sunil, B.M.Failure of slopes is often hydrodynamic in nature. Most of the failures are due to water infiltration and movement in the matrix of an otherwise dry soil mass. Consideration of multi-phase aspect of soil behavior is appropriate for logical judgments that culminate in appropriate solutions for slope stability problems. The mesh-free Discrete Element Method has been employed for understanding soil behavior. Different particle sizes and packing have been considered for analysis. Force networks, strain deviators, kinetic energy evolution have been extracted and interpreted and their utility in slope failure prediction has been highlighted. Results show that suction has considerable influence on the behavior of soil at the micro-scale. The soil suction manifests in the form of additional cohesion resulting in arresting the deformations due to applied load as evidenced by the obtained strain deviator plots, thereby aiding in the stability of the soil mass. The changes and fluctuations in kinetic energy can be an indicator of system instability. The research helps to adopt a particle-level approach toward real-time monitoring of stability of unsaturated slopes. © 2022, King Fahd University of Petroleum & Minerals.