Journal Articles
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Item Numerical investigations on the strength of L-shaped short reinforced concrete columns subjected to combined axial load and bending were undertaken for the purpose of providing design aids for structural engineers. The use of a computer lends itself naturally to the solution of the problem which generally requires an iterative process. Therefore, an attempt has been made in this paper to computerize the analysis procedure for L-shaped sections and in the accompanying paper (part II)‡ for T-shaped column sections. The ACI-318, CP-110 and IS-456 codes presented design aids only for square/rectangular and circular columns. Apparently this study constitutes the first to present the interaction curves for L-shaped and T-shaped column sections with the limit state analysis. © 1992.(Computer aided analysis of reinforced concrete columns subjected to axial compression and bending-I L-shaped sections) Mallikarjuna; Mahadevappa, P.1992Item Hydrodynamics characterization of a counter-current spray column for particulate scrubbing from flue gases(2008) Biswas, S.; Rajmohan, B.; Meikap, B.C.Growing environmental concern and tightening of the regulations for particulate emission from various sources force us to think of an alternative technology for their control, which is cost effective and of high performance. A spray column using a wet process to control the particulates offers design simplicity, and has various other advantages over other conventional equipment used in industry. This work presents the hydrodynamic study of the spray column for the removal of particulates from gaseous wastes. Experiments were carried out to quantify pressure drop (?P), for varied gas and liquid rates ranging from 3.084 × 10-3 to 5.584 × 10-3 Nm3/s and 8.35 × 10-6 to 33.34 × 10 -6 m3/s, respectively with QL/QG ratio ranging from 1.59 to 10.81 m3 per 1000 ACM (actual cubic meter). The maximum pressure drop incurred in the column is 327 N/m3, which is at a gas rate of 5.584 × 10-3 Nm3/s, liquid rate of 33.34 × 10-6 m3/s, and an inlet solid loading range of 0-2.5 kg/m3. This is quite low compared to other wet process-based equipment, thus making it a low power loss scrubber. These results have further demonstrated the impact of solid dust (particulates) on the pressuredrop-hydrodynamics. A correlation was put forward for prediction of the overall pressure drop in the column. The experimental values agreed well with the predicted values, with minimum percentage error and standard deviation. © 2008 Curtin University of Technology and John Wiley & Sons, Ltd.Item Performance of granular columns in dispersive soils(Thomas Telford Services Ltd ttjournals@ice.org.uk, 2014) Nayak, S.; Dheerendra Babu, M.R.; Shivashankar, R.; James, N.The soils found abundantly along the Konkan belt in peninsular India are lateritic soils and lithomargic clays. The locally available lithomargic clayey soils are problematic in the sense that their strength reduces drastically under saturation conditions, which is typical behaviour of the dispersive type of soil. Most foundations are placed on this soil layer. This paper presents results from a series of laboratory plate load tests carried out in unit cell tanks to investigate the behavior of granular columns in these weak (lithomargic clay) grounds. Tests are carried out with two types of loading: with the entire area in the unit cell tank loaded, to estimate the stiffness of the improved ground; and with only the granular column area loaded, to estimate its limiting axial capacity. Investigations were carried out by varying the area ratio (or spacing), diameter of granular columns, end condition and column configuration. The load-settlement behaviour, stiffness and bulging behaviour of granular columns are analyzed. It is found that the ground treated with granular columns exhibits a high load-carrying capacity and stiffness, and a significant reduction in settlement, compared with the untreated ground. © Ice publishing: All rights reserved.Item Shear Response of Pervious Concrete Column Improved Ground(Springer, 2021) Rashma, R.S.V.; Shivashankar, R.; Jayalekshmi, B.R.This study deals with numerical analysis of the shearing resistances of pervious concrete column improved ground vis-à-vis ordinary stone column improved ground. Analysis is done by numerically simulating a large shear test model, representing pervious concrete column improved ground. The parameters varied in this study are the depth of pervious concrete column/pile, floating and end-bearing piles, diameter, single pile and two-pile group and distance from the edge of loading area in the model. The shear response of improved ground is quantified by the applied strain controlled vertical load to the entire width of large shear test model that induces shear movements within the tank model. It is observed that the pervious concrete column improved ground shows better shear performance than ordinary stone column improved ground. It is also found that the pervious concrete column undergoes very small lateral deflections. It is also observed that more number of pervious concrete columns, and closer they are to the loaded area, better is the shear performance. © 2020, Indian Geotechnical Society.Item Liquefaction Mitigation Potential of Improved Ground Using Pervious Concrete Columns(Springer, 2022) Rashma, R.S.V.; Jayalekshmi, B.R.; Shivashankar, R.In this study, liquefaction mitigation potential of improved ground using pervious concrete column is being investigated. The seismic performance of pervious concrete column improved ground is compared with conventional stone column improved ground. Three-dimensional finite element analysis using OpenSeesPL software is conducted to study the ground lateral deformation and excess pore water pressure generation of pervious concrete column improved ground on a mildly sloping soil strata of infinite extent under seismic loading. The soil strata considered is fully saturated sand with an inclination of 4°. The parameters influencing seismic performance of improved ground like area ratio, founding depth of columns, diameter of columns and hydraulic conductivity of columns are considered. It is found from various response parameters that the pervious concrete column improved ground has better seismic performance than conventional stone column improved ground. The lateral deformation profile of pervious concrete column is found to be similar to that of concrete pile, allowing excess pore water pressure to dissipate through the pores of pervious concrete column. It is also concluded that pervious concrete columns could be used as an alternative to conventional stone columns to mitigate liquefaction to a larger extent. © 2021, Indian Geotechnical Society.Item Simplified Method to Predict Residual Strength of Reinforced Concrete Columns Under Natural Fire Conditions(Springer, 2024) Akkannavar, C.; Prashanth, M.H.; Joshi, C.Studies on the Reinforced Concrete (RC) columns under natural fire conditions are critical since the failure of columns leads to progressive failure of the building. Many experimental and analytical studies have been conducted to investigate the columns under fire conditions. Most studies have investigated fire conditions by utilizing standard time–temperature relationships such as ISO-834, ASTEM E119, and other nominal fire curves. This paper presents a simplified method to evaluate the axial capacity of RC columns subjected to natural or realistic fires. A parametric natural fire model is developed from EN.1991.1.2.2002 guidelines, considering important parameters into account to define the natural fire curve. Thermal analysis is carried out using the finite element software SAFIR to determine the temperature distribution within the column’s cross-section. The mechanical properties of concrete and steel change with an increase in temperature. The reduction factors for the compressive strength of concrete and the yield strength of steel at elevated temperatures are derived from Eurocodes. Using updated temperature-dependent strength parameters for concrete and steel, the capacity of a column is estimated. The proposed methodology can be used to estimate the residual strength of RC columns for realistic fire situations. © The Institution of Engineers (India) 2024.Item Predicting joint shear in beam–column connections using convolutional neural networks(Springer Science and Business Media B.V., 2025) Sidvilasini, S.; Palanisamy, T.Predicting joint shear at beam-column junctions (BCJ) is essential in structural engineering to ensure the safety and reliability of systems. Current methodologies using empirical calculations may rely on simplistic assumptions and insufficiently account for the many geometric factors and material properties that influence shear in BCJ. This research introduces a novel approach using Convolutional neural networks (CNNs) to predict joint shear. The collection comprises 515 joints, categorized into 210 exterior joints and 305 interior joints, characterized by 14 fundamental factors delineating their form and material properties. The predictive performance of the CNN model has been evaluated using known engineering codes, including ACI 318-19, NZS 3101:1-2006, IS 13920:2016, and several other data-driven models in the domain. Furthermore, it has been contrasted with an ensemble regression method. The study includes a thorough sensitivity analysis using a gradient-based method to determine the relative importance of input factors in predicting shear stress. The findings demonstrate the effectiveness of CNN in identifying complex relationships among joint parameters, thereby enabling precise predictions of joint shear. This method offers a promising alternative to traditional empirical formulas and enhances the understanding of structural behavior in BCJ. This study integrates contemporary machine learning algorithms with structural engineering concepts to optimize design processes and augment the safety and reliability of built environments. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2024.Item Residual strength estimation of RC columns subjected to elevated temperatures from stress block parameters(Emerald Publishing, 2025) Akkannavar, C.S.; Prashanth, M.H.Purpose: In structural fire engineering, the design of columns is done either by prescriptive approaches or by empirical equations derived from experimental research. Performance-based design is the emerging methodology for designing structures under fire, which is case-specific. There is a need to develop design equations from first principles to design/find the residual strength of the column at elevated temperatures. The present study aims to develop equations from stress block parameters to find the residual strength of reinforced concrete (RC) columns subjected to elevated temperatures. Design/methodology/approach: The stress-strain variation across the cross-section of the RC column is determined at elevated temperatures. Based on the updated stress distribution diagram, stress block parameters are derived for various depths of neutral axis (NA) and different temperatures. Using updated stress block parameters, Pu-Mu interaction curves are generated for elevated temperatures. The results are verified against conventional methods and experimental results. Findings: The load-carrying capacity calculated from the proposed methodology is analogous to the experimental results. The methodology can be utilized to estimate the residual strength of RC columns subjected to elevated temperatures. Originality/value: The work done here attempts to develop the equations to estimate the residual strength of the column. The work involves calculating the strength of columns subjected to fire curves. © 2024, Emerald Publishing Limited.Item Local buckling strength enhancement due to non-slender flanges in web perforated plain channel columns(Elsevier Ltd, 2025) Francis, R.; Shabhari, A.; Jeyapragasam, V.V.K.; Chandrasekar, D.Cold-formed steel columns are the primary compression members in housing and industrial storage racks, with discrete holes or closely spaced web perforations. The element slenderness and web perforations influence the local buckling capacity. This study examines the local buckling capacity of slender web plain channel cross-sections with non-slender or slender flanges in the presence of web perforations. Fourteen plain channel stub column tests were conducted on two cross-section aspect ratios, two perforation shapes, with three perforation orientations. Further, a comprehensive parametric study was conducted using validated Finite Element models. The local buckling strength of unperforated and web-perforated cold-formed plain channel columns is evaluated using the Direct Strength Method (DSM) and Modified Direct Strength Method (MDSM). The increase in local buckling strength due to non-slender flanges becomes significant, depending on the aspect ratio and non-dimensional local buckling slenderness ratio of the plain channel cross-section. This research provides the scope to expand the applicability of DSM and MDSM design strength predictions from cold-formed steel design to general thin-walled steel sections, where the welded thin-walled steel sections can have different element thicknesses. As the element thickness plays a crucial role in element slenderness and inter-element interaction, the local buckling capacity prediction available for uniform cross-section thickness can be unduly conservative. This study highlights the significance of element slenderness and effective area reduction due to perforation shape and orientation in the local buckling strength of cold-formed plain channel sections. © 2025 Institution of Structural Engineers. Published by Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.