Journal Articles
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/19884
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Item Performance enhancement of RC frames using welded wire fabrics - An experimental investigation(2010) Prashanth, M.H.; Chinnagiri Gowda, H.C.; Babu Narayan, K.S.; Ramana, K.V.The paper presents the performance enhancement of RC frames using welded wire fabrics to appraise beneficial effects of welded wire fabrics as lateral reinforcement in Reinforced Concrete elements. The RC frames subjected to lateral loading have been simulated to rhombus frame with vertical loading. The experimental investigation has been done on rhombus frame with vertical loading. Experimental program involved details of test specimens, test set-up and instrumentation. Comparison of conventional bare frames has been done for frame with welded wire fabrics as lateral reinforcement at discrete zone and frame with welded wire fabrics as lateral reinforcement throughout the length for the same volume fraction. Results of Experimental investigation have been reported from which the discussions and conclusions had been drawn. © 2010 Cafet-Innova Technical Society.Item Performance enhancement of preloaded RC beams using CFRP sheets(CAFET INNOVA Technical Society cafetinnova@gmail.com 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2012) Prashanth, M.H.; Suraj, K.; Babu Narayan, K.S.; Ravikumar, C.M.Retrofitting concrete structures with Carbon Fiber Reinforced Polymer (CFRP) has grown widely in most parts of the world today. The main reason for the wide spread application of FRP is that it is possible to obtain an effective strengthening with a relative small work effort. Furthermore it is possible to carry out strengthening work without changing the current appearance or dimension of the structure. To strengthen and increase the ductility of the structure, CFRP has become an innovative material in to the field of structural strengthening and rehabilitation. In the present experimental investigation, RC beams were preloaded up to 0 to 50% of the ultimate capacity and were applied with CFRP sheets at the soffit of the beams were compared with control beam. The Load vs deflection, and crack mechanism are studied. The use of CFRP sheets in the soffit of the beam has resulted in enhanced strength and ductility. © 2012 CAFET-INNOVA TECHNICAL SOCIETY.Item Experimental studies on Iron-ore tailing based interlocking paver blocks(2012) Ravi Kumar, C.M.; Anil, A.; Prashanth, M.H.; Venkat Reddy, D.Interlocking concrete block pavers (ICBP) has been extensively used in many of the countries due to concern with durability. They are utilized in a variety of commercial, municipal and industrial applications. The superior engineering properties, low maintenance, ease of placement and removal, aesthetic appeal and immediate availability are the primary reasons for choosing concrete block pavement over other paving surfaces. ICBP are colored using iron oxide pigments. The present investigation details the properties of ICBPs mixed with iron ore tailings as a partial replacement for cement. The paper discusses the experimental studies on strength characteristics and water absorption of iron ore tailings based concrete paver blocks by considering actual area and plan area and results has been compared with that of conventional concrete paver blocks. © 2012 Cafet-innova technical society. © 2012 Cafet-Innova Technical Society.Item Experimental investigation of RC frames using CFRP sheets(2013) Prashanth, M.H.; Babu Narayan, K.S.; Venkataramana, K.; Sajith, M.Reinforced Concrete frames are the main load resisting systems used in practice all over the world. These frames will be subjected to sway, due to lateral loading most of the times by either earthquake or wind. Ductility and energy dissipation capacity of the frame are the key parameters for better performance under the action of the sway loading. Retrofitting using the new generation material such as carbon fiber reinforced plastic sheets (CFRP) shows much enhancement in these properties of laterally loaded frames. Frames subjected to lateral loading introduce collapse mechanism due to the formation of the plastic hinges at critical hinge locations. An experimental investigation of partially and fully CFRP wrapped reinforced concrete (RC) frames when compared to conventional(bare) frame has been carried out, to bring out the importance of critical engineered locations to be wrapped. © 2013 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item Role of longitudinal reinforcement on the behavior of under reinforced concrete beams subjected to fatigue loading(Elsevier Ltd, 2019) Prashanth, M.H.; Singh, P.; Chandra Kishen, J.M.C.In this work, the role of steel reinforcement in under reinforced concrete beams when subjected to flexural fatigue loading is studied using the acoustic emission (AE) technique. Three-point bend notched beams of three different sizes and with varying reinforcement ratios are subjected to step-wise increasing variable amplitude fatigue loading. The crack mouth opening displacement (CMOD) and AE parameters are analyzed to study the evolution of damage, load carrying and failure mechanisms in under reinforced concrete beams. It is concluded that the presence of reinforcement substantially increases the fatigue life. Further, the CMOD could be used as a criterion for failure in reinforced concrete beams under fatigue loading. © 2019 Elsevier LtdItem Flexural behavior of reinforced high performance self-compacting alkali activated slag concrete beams(Associated Cement Companies Ltd., 2020) Manjunath, R.; Prashanth, M.H.; Narasimhan, M.C.; Bala Bharathi, U.K.The present manuscript discusses the results of a series of tests conducted to study, in detail, the performance of reinforced, alkali activated slag concrete beams in terms of their flexural behavior. The present authors have developed and evaluated the performance of a new class of high-performance, self-compacting, alkali-activated slag concrete (HPAASC) mixes, using three industrial by-products, all from the iron and steel industry. While these HPAASC mixes have higher compressive strengths (around 70-90 MPa), reasonable splitting and flexural strengths along with moduli of elasticity, here, in this investigation, reinforced concrete beams made of these mixes are evaluated for their flexural performances in order to promote their applicability in large-scale infrastructural applications. Twelve under-reinforced concrete beams, were cast and were tested. Their flexural behaviors were experimentally evaluated in terms of loads at first crack, ultimate loads, strain-distributions, their load-deflection characteristics along with ductility values. Results of the present study indicate that, all the reinforced beams made of HPAASC mixes exhibit comparable flexural performances, as compared to that of beams cast with a reference OPC-based concrete mix, making a strong case for the possible application of these HPAASC mixes as structural elements in large-scale infrastructure projects. © 2020, Associated Cement Companies Ltd.. All rights reserved.Item Experimental study on shear reinforced and shear deficient RC beams subjected to preloading and wrapping with CFRP sheets(Elsevier Ltd, 2023) Prashanth, M.H.; Manjunath, R.; Koppad, A.; B, B.; Kuttagola, I.An experimental work has been carried out to study the shear reinforced and shear deficient RC beams which are subjected to preloading and wrapping with CFRP sheets. Shear reinforced beams were wrapped with CFRP sheets and subjected to 0% and 50% preloading. Shear deficient beams were wrapped with CFRP sheets and subjected to 0, 50% and 70% of preloading. CFRP wrapped beams of shear reinforced (A2, A3) and shear deficient (B2 B3 B4) show substantial improvement in ductility and an increased ultimate load carrying capacity when compared to respective control beams. Due to preloading, ductility remains same with the marginal decrease in ultimate load carrying capacity when compared to respective 0% preloaded beam specimens. CFRP wrapping is found to be very effective in arresting initiation and development of cracks with and without preloading. © 2023Item Numerical study on the effect of steel fibers on fracture and size effect in concrete beams(Elsevier Ltd, 2023) Yadav, D.; Prashanth, M.H.; Kumar, N.The construction sector uses concrete extensively all around the world. Concrete contains a lot of microcracks even before it is loaded. When a tensile force is applied, these microcracks attempt to open up. While designing, the strength of concrete in its tensile zone is ignored. The strength and ductility of the concrete can be improved due to the addition of steel fibers. Steel fibers use a bridge mechanism to restrict the micro-cracks spread. This study uses ABAQUS to numerically analyze the behaviour of the Steel Fiber Reinforced Concrete (SFRC) beams. Two grades of concrete are studied, M20 and M60, for varying volumetric percentages of steel fibers. It was observed from the study that the ultimate load increases by around 52% and 41% for M25 and M60 grade concrete, respectively, by adding 1% of steel fiber. Fracture properties such as fracture toughness and fracture energy are calculated. The addition of steel fibers enhanced fracture toughness and energy significantly. Adding 1% fiber increases fracture toughness by around 56% and 34% and fracture energy by around 169% and 136% for M25 and M60 concrete, respectively. The size effect on SFRC beams is studied to determine the size-independent fracture parameters. © 2023Item Direct estimation of fractal dimension for an irregular surface using the roughness parameter approach(Elsevier B.V., 2024) Raj S, P.; Prashanth, M.H.The fracture process of any material is a natural response towards external loading. These fracture surfaces exhibit a fractal pattern that can be analyzed quantitatively by measuring its fractal dimension (FD). Subsequently, this FD value can be correlated with different properties of the material. Various versions of the cubic covering method (CCM) can accurately describe the fractal patterns present on irregular surfaces with minimum approximation. However, these methods are not direct methods for determining the FD, as they rely on the covering process of cubes rather than considering the irregular surface area. Considering this, a new approach known as the Roughness Parameter Method (RPM) was studied. This method involves the surface area of an irregular surface to measure surface roughness parameters for the direct estimation of the FD. Comparative analysis between direct and indirect methods to measure FD was carried out using Takagi surfaces and real-world irregular surfaces. © 2024 Elsevier LtdItem 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.