K.s Jagadish | Indian Institute of Science (original) (raw)

Papers by K.s Jagadish

THE DYNAMIC RESPONSE OF A HIGHWAY BRIDGE UNDER MOVING LOADS IS USUALLY STUDIED BY TREATING THE BR... more THE DYNAMIC RESPONSE OF A HIGHWAY BRIDGE UNDER MOVING LOADS IS USUALLY STUDIED BY TREATING THE BRIDGE AS A BEAM. SUCH A TREATMENT WOULD BE SATISFACTORY IF THE SPAN/WIDTH RATIO OF THE BRIDGE IS LARGE. HOWEVER, A MAJORITY OF HIGHWAY BRIDGES MAY HAVE SPANS COMPARABLE TO THE WIDTHS. FOR SUCH BRIDGES, THE BEAM THEORY IS NOT ADEQUATE AND A SUITABLE TWO- DIMENSIONAL THEORY WILL HAVE TO BE ADOPTED TO CONSIDER THE INFLUENCE OF THE TRANSVERSE FLEXIBILITY OF THE BRIDGE ON ITS RESPONSE. IN THIS PAPER THE DYNAMIC RESPONSE OF SIMPLE-SPAN BEAM AND SLAB HIGHWAY BRIDGES SUBJECTED TO A MOVING CONCENTRATED FORCE IS STUDIED. THE HIGHWAY BRIDGE IS TREATED AS AN ORTHOTROPIC PLATE, AND THE NORMAL MODE METHOD IS USED IN THE RESPONSE ANALYSIS. NUMERICAL RESULTS ARE PRESENTED FOR TYPICAL CASES IN THE FORM OF AMPLIFICATION SPECTRA AND HISTORY CURVES. /AUTHOR/

Lecture Notes in Civil Engineering, 2021

SN Applied Sciences, 2020

Journal of The Institution of Engineers (India): Series A, 2020

Journal of Engineering Mechanics, 1989

In this paper, a single-story, bilinear-hysteretic structure, square in plan and supported on fou... more In this paper, a single-story, bilinear-hysteretic structure, square in plan and supported on four columns, subjected to two horizontal ground motions is studied. The model is assumed to possess three degrees of freedom, viz., translational displacements along the two horizontal orthogonal directions and a rotation about the vertical axis. Interaction of the bending moments in the two perpendicular directions has been considered.

Applied Scientific Research, 1964

Earthquake Engineering & Structural Dynamics, 1979

Two storey bilinear hysteretic structures have been studied with a view to exploring the possibil... more Two storey bilinear hysteretic structures have been studied with a view to exploring the possibility of using the dynamic vibration absorber concept in earthquake‐resistant design. The response of the lower storey has been optimized for the Taft 1952, S69°E accelerogram with reference to parameters such as frequency ratio, yield strength ratio and mass ratio. The influence of viscous damping has also been examined.

International Journal of Applied Earth Observation and Geoinformation, 2004

Journal of the Indian Society of Remote Sensing, 2003

Urban growth identification, quantification, knowledge of rate and the trends of growth would hel... more Urban growth identification, quantification, knowledge of rate and the trends of growth would help in regional planning for better infrastructure provision in environmentally sound way. This requires analysis of spatial and temporal data, which help in quantifying the trends of growth on spatial scale. Emerging technologies such as Remote Sensing, Geographic Information System (GIS) along with Global Positioning System (GPS) help in this regard. Remote sensing aids in the collection of temporal data and GIS helps in spatial analysis. This paper focuses on the analysis of urban growth pattern in the form of either radial or linear sprawl along the Bangalore-Mysore highway. Various GIS base layers such as builtup areas along the highway, road network, village boundary etc. were generated using collateral data such as the Survey of India toposheet, etc. Further, this analysis was complemented with the computation of Shannon's entropy, which helped in identifying prevalent sprawl zone, rate of growth and in delineating potential sprawl locations. The computation Shannon's entropy helped in delineating regions with dispersed and compact growth. This study reveals that the Bangalore North and South taluks contributed mainly to the sprawl with 559% increase in built-up area over a period of 28 years and high degree of dispersion. The Mysore and Srirangapatna region showed 128% change in built-up area and a high potential for sprawl with slightly high dispersion. The degree of sprawl was found to be directly proportional to the distances from the cities.

Proceedings of the Indian Academy of Sciences Section C: Engineering Sciences

An attempt is made in this paper to arrive at a methodology for generating building technologies ... more An attempt is made in this paper to arrive at a methodology for generating building technologies appropriate to rural housing. An evaluation of traditional] ' modern' technologies currently in use reveals the need for alternatives. The lacunae in the presently available technologies also lead to a definition of rural housing needs. It is emphasised that contending technologies must establish a 'goodness of fit' between the house form and the pattern of needs. A systems viewpoint which looks at the dynamic process of building construction and the static structure of the building is then suggested as a means to match the technologies to the needs. The process viewpoint emphasises the role of building materials production and transportation in achieving desired building performances. A couple of examples of technological alternatives like the compacted soil block and the polythene-stabilised soil roof covering are then discussed. The static structural system viewpoint is then studied to arrive at methodologies of cost reduction. An illustrative analysis is carried out using the dynamic programming technique, to arrive at combinations of alternatives for the building components which lead to cost reduction. Some of the technological options are then evaluated against the need patterns. Finally, a guideline for developments in building technology is suggested.

Curr Sci, 2004

We present here the research, development and dissemination activities on efficient wood-burning ... more We present here the research, development and dissemination activities on efficient wood-burning devices conducted at ASTRA, Indian Institute of Science, Bangalore. The fuel-efficient ASTRA stove, with a thermal efficiency of 44%, was developed and about 1.5 million stoves disseminated in Karnataka. The level of acceptance was around 60%. The technical performance of the stoves in the field as well as the research, development and dissemination challenges are presented. The analysis highlights the need for (i) more stove designs to cater to the diverse cooking practices in different regions; (ii) clean combustion with improved efficiency and no adverse impacts on global environment, and (iii) development of cost-effective and participatory dissemination modules based on pilot field experiments.

The two recent earthquakes of Latur (1993) and Kachchh (2001) in India have caused large-scale da... more The two recent earthquakes of Latur (1993) and Kachchh (2001) in India have caused large-scale damage to buildings and in particular to un-reinforced masonry buildings. In this paper an attempt is made to understand the behaviour of masonry buildings during earthquakes based on post earthquake survey. These studies have revealed the inadequacies in the current provisions for earthquake resistant design. The paper also reports the results of the dynamic analysis of typical Indian brick masonry buildings subjected to three different earthquake ground motions. The stress distributions obtained from this analysis have shown that out-of-plane flexural stresses and in-plane shear stresses exceed their strength limits. Based on stress analysis and observed damage patterns of masonry buildings, it may be concluded that out-of-plane flexural failure of walls is primarily responsible for collapse of masonry buildings during earthquakes. In order to prevent this kind of failure and to improve ...

Load bearing masonry walls of a building, when subjected to earthquake experience in plane and ou... more Load bearing masonry walls of a building, when subjected to earthquake experience in plane and out of plane forces which may lead to sudden collapse. Since a state of pure shear leads to diagonal tension and compression, Split tension tests are conducted on masonry panels to obtain the tensile strength of masonry. The tensile strength of masonry is determined with masonry bed joints as horizontal and with bed joints inclined at 45o to the horizontal. Stress analysis has been carried out using finite element analysis. Both isotropic and orthotropic cases were considered. Split tensile strength of masonry is evaluated from the formula obtained by finite element analysis and the experimental failure loads.

Technologies and Innovations for Development, 2012

The housing sector is generating worldwide substantial environmental impacts. In fact, it contrib... more The housing sector is generating worldwide substantial environmental impacts. In fact, it contributes to about half of the total energy consumption of high income countries and is responsible of a major share of greenhouse gas emissions also in development and transition (D&T) nations. Scientific data on environmental impacts of building materials and technologies in D&T countries are rather limited and it is difficult to make informed choices aiming at reducing such impacts. The study aims at filling a gap in the assessment and documentation of environmental impacts of building technologies in India and in D&T countries in general. It is based on a detailed analysis of various walling technologies used in single family houses of Kutch District, Gujarat State, India, including traditional, modern and alternative new technologies. Based mainly on primary data, the impacts have been assessed including the production chain of materials, their transportation on site, all construction procedures as well as the maintenance activities over fifty years, whereas the impacts due to demolition of the structures at the end of their life cycle have been evaluated through qualitative analysis. Environmental impacts are represented through indicators such as the total energy consumption (embodied energy), the share of non renewable energies (NRE), the corresponding amount of CO 2 emissions and the consumption of water. Various phases of production processes (construction, transport and maintenance) are represented separately in order to inform on their respective quantitative relevance.

Open Journal of Energy Efficiency, 2017

It is well-known that a product or a system is sustainable if it is economically viable, socially... more It is well-known that a product or a system is sustainable if it is economically viable, socially acceptable and environmentally friendly. Load bearing masonry is one such example which is quite sustainable, especially if the masonry units are locally available. It is important to quantify the environmental benefits and cost, if an alternative to an existing technology is to be suggested. Of course the issues related to acceptance have to be discussed and addressed. This paper presents the quantification of embodied energy and cost of limepozzolana-cement (LPC) geopolymer based masonry units made using locally available bulk ingredients viz. tank-bed soil (TBS) and brick-powder (BP). The masonry adobe units developed have achieved the target performance in terms of strength, low water absorption and relative ease of production. Simultaneously the issues related to cost are also discussed in this paper. The studies have revealed that the bulk contributor to embodied energy and cost of geopolymer adobes are the alkaline materials viz sodium hydroxide and sodium silicate. However, the embodied energy and cost per unit strength appears to be better than that of conventional table moulded bricks in south India, especially when alkaline solution at 2M concentration is used with LPC.

Building and Environment, 1987

Erosion resistance of pressed soil blocks used for wall construction is discussed. The spray eros... more Erosion resistance of pressed soil blocks used for wall construction is discussed. The spray erosion test using a standardized shower spray is discussed. Spray erosion behaviour of pressed soil blocks made out of five different soils is presented. Results of laboratory and field tests are compared. Effect of clay content of the soil and density of the pressed soil block on erosion are discussed. Also the effect of water-proof coatings on erosion of soil blocks is presented. Erosion resistance of soil blocks stabilized with organic (jaggery syrup and starch) or inorganic binders is also discussed.

Electronic Journal of Structural Engineering

The aim of present study is to determine the mechanical properties of hollow concrete block mason... more The aim of present study is to determine the mechanical properties of hollow concrete block masonry externally bonded with coir and glass textile reinforced mortar composites. The properties of textile composites were determined by testing TRM Coupons. A total number of 39 prisms were cast. The block masonry prisms were externally bonded with coir and glass textile fibre mesh with mortar. The elastic properties of block masonry, shear and flexural strength were determined for both unreinforced and strengthened specimens. The results showed that increasing the number of layers of textile fibers, enhanced the flexural capacity of TRM coupons. The provision of connectors also enhanced flexural strength. The stiffness of unreinforced masonry prisms was found to increase by strengthening with textile reinforcements even though the increase in compressive strength is marginal. There is a significant enhancement in flexural strength and shear bond strength when compared to unreinforced mas...

This paper deals with an experimental investigation on the strength of stone and stone masonry. G... more This paper deals with an experimental investigation on the strength of stone and stone masonry. Granitoidgneiss is commonly used for masonry construction in India. The compressive strength of stone has been determined through 80 mm size cubes. It has been found that the compressive strength of granitoid-gneiss is greater when the load is parallel to the mineral bands. The compressive strength of stone masonry was studied through masonry prisms using 1:4 and 1:8 cement mortars. These tests have revealed that masonry strength is higher when the load applied is parallel to the mineral bands. The f lexural bond strength of stone masonry walls was studied through full-scale tests. Flexural bond strength appears to play a major role in the failure of stone masonry walls.

Energy and Buildings, 2003

Considerable amount of energy is spent in the manufacturing processes and transportation of vario... more Considerable amount of energy is spent in the manufacturing processes and transportation of various building materials. Conservation of energy becomes important in the context of limiting of green house gases emission into the atmosphere and reducing costs of materials. The paper is focused around some issues pertaining to embodied energy in buildings particularly in the Indian context. Energy consumption in the production of basic building materials (such as cement, steel, etc.) and different types of materials used for construction has been discussed. Energy spent in transportation of various building materials is presented. A comparison of energy in different types of masonry has been made. Energy in different types of alternative roofing systems has been discussed and compared with the energy of conventional reinforced concrete (RC) slab roof. Total embodied energy of a multi-storeyed building, a load bearing brickwork building and a soil-cement block building using alternative building materials has been compared. It has been shown that total embodied energy of load bearing masonry buildings can be reduced by 50% when energy efficient/alternative building materials are used.