Articles written in Sadhana

    • Comparative study of wind induced mutual interference effects on square and fish-plan shape tall buildings


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      This paper deals with comparative study of wind-induced mutual interference effects on twin Square and Fish- plan shape building models having equal volume. Wind induced pressure and force is measured through experiments under boundary layer wind tunnel for interference and isolated wind incidencecondition with building model of scale 1:300. For isolated condition’s study two wind incidences i.e. 00 and 1800 is considered whereas; for interference conditions five different orientation of twin interfering building models are considered. The distance between the twin building models is fixed at 10% of the height of principal model. The variation of coefficient of wind pressure on different surfaces of the model is shown by contour plots. To examine the mean variation along the faces Face-Average Cp has been calculated, plotted and discussed to a great extent. The interference study is done in order to understand the effects of different conditions that can arise in real life situations and the differences associated with them. The concluding remarks states the dominance of Drag and Lift forces at isolated 00 and 1800 wind incidences for Fish- plan shape model and at isolated 00 wind direction at Square shape model. Also, the overall efficiency in terms of Base shear of principal building is enhanced due to interference effect; with maximum efficiency exhibited by Back-to-Back wind interferencen condition when only Fish- plan shape model is considered. Overall, maximum efficiency in terms of induced wind pressure and base shear is exhibited by Square- plan shape model at Full Blockage condition.

    • Effect of wind load on irregular shape tall buildings having different corner configuration


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      Tall buildings are mainly designed to resist wind loads because wind-induced vibration is more critical for occupant’s comfort level on top of the building. Therefore, evaluation of wind-generated pressure is must for such type of tall buildings. Investigation of response due to wind loads on tall buildings is possible by employing numerical modelling such as computational fluid dynamic tools. Regular plan shape structure can be designed for wind load using various international standards and available literatures. In this research comparisonis made between four models in which model-A and B is having the regular shape while model-C and D are of irregular shape. These study is useful for the designer to evaluate the response of structures under strong wind conditions. The grid sensitivity and validation study are performed for rectangular shape tall buildings. Validation of the study shows that numerical simulation results are more or less identical with experimental results. In present research work selected building models have equal cross-sectional area and height. Numericalstudy performed by employing the k-ε turbulence model and the results are compared with the experimental findings. Out of all the four models, the Y-shape model with round in corners has a minimum base moment and the least coefficient of drag.

    • Heavy metals concentrations and risk assessment in the sediment of Ganga River between Kanpur and Prayagraj, U.P., India


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      This study analyses the heavy metal contamination in freshly deposited sediment of 210 km stretch of River Ganga between Kanpur and Prayagraj, Uttar Pradesh (U.P.), India. As per APHA (2012)30 digested samples were prepared after collecting from 10 sampling sites. Then the samples were analyzed for 8 heavymetals namely Cadmium (Cd), Chromium (Cr), Copper (Cu), Iron (Fe), Manganese (Mn), Nickel (Ni), Lead (Pb), and Zinc (Zn) by Atomic Absorption Spectroscopy (AAS) (Shimadzu AA-6300). Risk assessment was done by employing four pollution indices. The average values of contamination factor (CF) indicate that the level of contamination by Pb is moderate (1<CF<3) and significant by Cd (3<CF<6). Whereas, the average value of Geo-accumulation index (Igeo) indicates that the sediments are uncontaminated or in a moderate level of contamination by Pb (0<Igeo<1) and in a moderate level of contamination by Cd (1<Igeo<2), which may have harmful effects on Ganga River ecology. The values of Pollution load index (PLI) indicate that the Ganga River sediment has a low level of contamination. Based on various pollution indicators, it has beenobserved that concentrations of Cd and Pb in the river sediment is a matter of concern and may lead to further deterioration of sediment quality in near future due to increasing anthropogenic activities in the river basin, hence proper management strategies should be taken to control the direct dumping of both domestic and industrial wastewater in the river.

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