Browsing by Author "Muthukumar, G ."

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Analytical modeling of damping
(Indian Concrete Journal, 2014) Muthukumar, G .; Kumar, Manoj
Damping is a desirable property of a structure from the earthquake resistant point of view. Thus, in dynamic analysis of structures, the modeling of damping plays a crucial role in achieving the safe response of structure. Any deviation in the representation of damping from the actual damping in the analytical model may result anything between small failure and catastrophic collapse, thus highlighting the importance of damping in a dynamic analysis of structures. Unlike mass and stiffness matrices, damping cannot be determined analytically thus bringing dynamic analysis in a state of uncertainty. Various representations of damping have evolved over the period of years which are tailor-made to specific problems. It has been generally accepted that there is no single universally accepted method for the representation of damping in an analytical manner. In this paper, an attempt has been made in reviewing the various damping models that are currently in practice.
Behaviour of shear wall with openings – A review
(Indian Concrete Journal, 2017) Muthukumar, G .; Kumar, Manoj
A Brief Review of Structural Aspects of IS 16700:2017
(Springer, 2020) Muthukumar, G .; Mittal, Ravi Kant
Rapidly increasing urbanisation and subsequently ascending shortage of land in the urban areas has pushed the design engineers to switch to the utilisation of the vertical spaces in the form of high-rise buildings and reduce the horizontally vast design popular in the previous era. However, this step not only enhances the criticality of the design processes but also increases our dependency on design codes. Talking specifically about India, the dependency of Indian design community was majorly on international codes due to the non-availability of a design code for tall buildings. It also gave rise to a wide gap in the design community about different provisions. However, recently Bureau of Indian Standards has launched First Tall Building Code of India, IS 16700:2017 “Criteria of Structural Safety of Tall Concrete Buildings.” Despite a good effort of bringing the Indian design community at the same base scale, this code still lacks in a clear depiction of certain aspects. It is also felt that commentary of this code may be provided in a similar fashion as of ASCE 07:2016, ACI 318:2014 to facilitate the adoption of the code. As a first step to it, this study is mainly aimed towards understanding some of the critical structural aspects of the code so as to develop a better understanding in practitioners and design engineers about it. Moreover, some critical clauses are also highlighted through a comparison of the same with various existing international standards.
Economic input-output LCA of precast corundum-blended ECC overlay pavement
(Elsevier, 2022-09) Muthukumar, G .; Lahoti, Mukund
Many studies have explored the prospect of using Engineered Cementitious Composites (ECC) in rigid pavements by looking at aspects such as mechanical performance, temperature susceptibility, cost, and environmental impact. Although ECC is an excellent choice because of its high tensile capacity, its major drawback for pavement applications is that it lacks roughness because of no coarse aggregates. Recently, an ECC mix containing corundum fine aggregates has shown remarkably higher skid resistance and drainage performance for pavement applications. The current study attempts to perform a comprehensive Economic Input-Output Life Cycle Analysis (EIO-LCA) of a concrete pavement having a precast corundum-blended ECC overlay. This LCA is compared with the LCA of a conventional rigid pavement and a full-depth conventional ECC pavement. The study includes both an inventory analysis using EIO-LCA and an impact assessment at midpoint and endpoint level on selected impact categories. It is found that the pavement having a precast corundum-blended ECC overlay is more economically and environmentally sustainable than the full-depth concrete and ECC pavements, and also has lower life-cycle impacts overall.
Failure criteria of concrete- A review
(TechnoPress, 2014-11) Muthukumar, G .; Kumar, Manoj
Concrete is a versatile construction material used in many engineering structures. The design of concrete structures requires a thorough understanding of their material properties under various loading conditions. Several experimental investigations have been carried out to examine the behavior of concrete. This paper is an attempt to summarize the behavioral aspects of concrete under different loading conditions. Failure models developed out of these experimental investigations are reported in this paper with their merits and demerits.
Influence of Opening Locations on the Structural Response of Shear Wall
(Hindawi Publishing Corporation, 2014) Muthukumar, G .; Kumar, Manoj
Shear walls have been conferred as a major lateral load resisting element in a building in any seismic prone zone. It is essential to determine behavior of shear wall in the preelastic and postelastic stage. Shear walls may be provided with openings due to functional requirement of the building. The size and location of opening may play a significant role in the response of shear walls. Though it is a well known fact that size of openings affects the structural response of shear walls significantly, there is no clear consensus on the behavior of shear walls under different opening locations. The present study aims to study the dynamic behavior of shear walls under various opening locations using nonlinear finite element analysis using degenerated shell element with assumed strain approach. Only material nonlinearity has been considered using plasticity approach. A five-parameter Willam-Warnke failure criterion is considered to define the yielding/crushing of the concrete with tensile cutoff. The time history responses have been plotted for all opening cases with and without ductile detailing. The analysis has been done for different damping ratios. It has been observed that the large number of small openings resulted in better displacement response.
Influence of Openings on the Structural Response of Shear Wall
(Hindawi Publishing Corporation, 2014) Muthukumar, G .; Kumar, Manoj
Shear walls have been conferred as a major lateral load resisting element in a building in any seismic prone zone. It is essential to determine behavior of shear wall in the preelastic and postelastic stage. Shear walls may be provided with openings due to functional requirement of the building. The size and location of opening may play a significant role in the response of shear walls. Though it is a well known fact that size of openings affects the structural response of shear walls significantly, there is no clear consensus on the behavior of shear walls under different opening locations. The present study aims to study the dynamic behavior of shear walls under various opening locations using nonlinear finite element analysis using degenerated shell element with assumed strain approach. Only material nonlinearity has been considered using plasticity approach. A five-parameter Willam-Warnke failure criterion is considered to define the yielding/crushing of the concrete with tensile cutoff. The time history responses have been plotted for all opening cases with and without ductile detailing. The analysis has been done for different damping ratios. It has been observed that the large number of small openings resulted in better displacement response.
Nonlinear finite element dynamic analysis of squat shear wall with openings
(Springer, 2013-11) Muthukumar, G .
Shear wall has been considered as a major lateral load-resisting element inmultistoried building located in wind- or earthquake-prone zone. The behavior ofshear wall under various loading conditions has been the subject of intenseresearch for the last few decades. The behavior of shear walls without openingsis completely well understood and well documented in literature. The use ofsquat shear wall has been found in many low-rise buildings. On the other hand,squat shear walls may also be provided with openings due to the functionalrequirement such as placement of doors/windows in the building. The size andlocation of the opening play a significant role in the response of the shearwall. Even though it is intuitively known that the size of opening hassignificant effects on the behavior of a shear wall, it is desirable to know thelimiting size of opening in the shear wall, beyond which the shear walls mayfail or become unserviceable, especially when subjected to severe earthquakeground motions. In this study, the materially nonlinear dynamic response of theshear wall, with and without openings for different damping ratios, subjected toEL Centro earthquake has been captured. For dynamic analysis, constantacceleration Newmark β method of direct time integration has been used.From the study, it was observed that the presence of opening results in severedisplacements and stresses on the shear wall and also results in stressconcentration near the opening tip. Hence, the presence of damping has beenconsidered to be vital for large opening under severe dynamic loadingconditions.
A Relook on Dosage of Basalt Chopped Fibres and Its Influence on Characteristics of Concrete
(Springer, 2020) Muthukumar, G .
In recent years, the need for sustainable yet economically viable structural materials has drawn special attention of the construction industry apart from the traditional parameters concerning safety and serviceability. One such material of interest gaining popularity in the twentieth century is the basalt fibre, due to its cost-effectiveness and desirable engineering properties, especially with respect to fire resistance. Basalt fibres are formed from basalt rocks and hence fulfil the concept of sustainable design and green building. Basalt can commonly be used as a structural reinforcing material in the form of bars, sheets, chopped fibres, etc. Talking specifically about chopped basalt fibres, the dosage of fibre plays an important role in its case. This paper mainly highlights the existing studies on the optimum dosage of chopped basalt fibres with respect to strength aspect and points out several critical comments on the relation of fibre content with workability through experimental testing.